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1
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Koloi S, Ganguly I, Singh S, Dixit S. Whole genome re-sequencing reveals high altitude adaptation signatures and admixture in Ladakhi cattle. Gene 2025; 933:148957. [PMID: 39306203 DOI: 10.1016/j.gene.2024.148957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 08/19/2024] [Accepted: 09/18/2024] [Indexed: 10/01/2024]
Abstract
Ladakhi cattle, native to the high-altitude region of Ladakh in northern India (ranging from 3,000 to 5,000 m above sea level), have evolved unique genetic adaptations to thrive in harsh environmental conditions, such as hypoxia, extreme cold, and low humidity. This study explored the genome of Ladakhi cattle to investigate genetic structure, selection signatures, and adaptive mechanisms. Whole genome sequencing reads, generated on Illumina NovaSeq 6000 platform, were aligned to the Bos taurus reference genome with BWA-MEM. SNPs were identified and filtered using GATK and bcftools, and functionally annotated with SnpEff. For population genomic analysis, PCA and admixture modeling assessed genetic structure, while Neighbor-Joining trees, LD decay, nucleotide diversity (π), and FST evaluated phylogenetic relationships and genetic variation. Selective sweeps were detected using RAiSD, and gene-set enrichment and protein-protein interaction analyses were conducted to explore functional pathways related to adaptation. The study revealed 3,759,279 unique SNPs and demonstrated that Ladakhi cattle form a distinct genetic cluster with an estimated admixture of 68 % Bos indicus and 32 % Bos taurus ancestry. Key findings include rapid linkage disequilibrium decay, low inbreeding level, and the identification of selection signatures and genes associated with hypoxia response, energy metabolism, and cold adaptation. Mean nucleotide diversity (π, 0.0037) and FST values indicated moderate genetic differentiation from other breeds. The analysis highlighted selection signatures for genes like HIF1A, ENO4, ANGPT1, EPO, NOS3, MAPK3, HMOX1, BCL2,CAMK2D, MTOR, AKT2,PIK3CB, and MAP2K1, among others, including various keratin and heat shock proteins. The interaction between genes associated with hypoxia signaling (HIF-1) and other enriched pathways such as PI3K, mTOR, NFκB, ERK, and ER stress, reveals a complex mechanism for managing hypoxic stress in Ladakhi cattle. These findings offer valuable insights for breeding programs aimed at enhancing livestock resilience in extreme environments and enhance understanding of mammalian adaptation to high-altitude conditions.
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Affiliation(s)
- Subrata Koloi
- Division of Animal Genetics, ICAR-National Bureau of Animal Genetic Resources, Karnal 132001, India; Division of Animal Genetics and Breeding, ICAR-National Dairy Research Institute, Karnal 132001, India
| | - Indrajit Ganguly
- Division of Animal Genetics, ICAR-National Bureau of Animal Genetic Resources, Karnal 132001, India.
| | - Sanjeev Singh
- Division of Animal Genetics, ICAR-National Bureau of Animal Genetic Resources, Karnal 132001, India
| | - Satpal Dixit
- Division of Animal Genetics, ICAR-National Bureau of Animal Genetic Resources, Karnal 132001, India.
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2
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Harrington CT, Sotillo E, Dang CV, Thomas-Tikhonenko A. Tilting MYC toward cancer cell death. Trends Cancer 2021; 7:982-994. [PMID: 34481764 PMCID: PMC8541926 DOI: 10.1016/j.trecan.2021.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 12/12/2022]
Abstract
MYC oncoprotein promotes cell proliferation and serves as the key driver in many human cancers; therefore, considerable effort has been expended to develop reliable pharmacological methods to suppress its expression or function. Despite impressive progress, MYC-targeting drugs have not reached the clinic. Recent advances suggest that within a limited expression range unique to each tumor, MYC oncoprotein can have a paradoxical, proapoptotic function. Here we introduce a counterintuitive idea that modestly and transiently elevating MYC levels could aid chemotherapy-induced apoptosis and thus benefit the patients as much, if not more than MYC inhibition.
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Affiliation(s)
- Colleen T Harrington
- Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Elena Sotillo
- Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Chi V Dang
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA; Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, PA 19104, USA; Ludwig Institute for Cancer Research, New York, NY 10017, USA
| | - Andrei Thomas-Tikhonenko
- Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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3
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Ahmadi SE, Rahimi S, Zarandi B, Chegeni R, Safa M. MYC: a multipurpose oncogene with prognostic and therapeutic implications in blood malignancies. J Hematol Oncol 2021; 14:121. [PMID: 34372899 PMCID: PMC8351444 DOI: 10.1186/s13045-021-01111-4] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/12/2021] [Indexed: 12/17/2022] Open
Abstract
MYC oncogene is a transcription factor with a wide array of functions affecting cellular activities such as cell cycle, apoptosis, DNA damage response, and hematopoiesis. Due to the multi-functionality of MYC, its expression is regulated at multiple levels. Deregulation of this oncogene can give rise to a variety of cancers. In this review, MYC regulation and the mechanisms by which MYC adjusts cellular functions and its implication in hematologic malignancies are summarized. Further, we also discuss potential inhibitors of MYC that could be beneficial for treating hematologic malignancies.
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Affiliation(s)
- Seyed Esmaeil Ahmadi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Samira Rahimi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Bahman Zarandi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Rouzbeh Chegeni
- Medical Laboratory Sciences Program, College of Health and Human Sciences, Northern Illinois University, DeKalb, IL, USA.
| | - Majid Safa
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran.
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran.
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4
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Goat Genomic Resources: The Search for Genes Associated with Its Economic Traits. Int J Genomics 2020; 2020:5940205. [PMID: 32904540 PMCID: PMC7456479 DOI: 10.1155/2020/5940205] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/30/2020] [Accepted: 07/24/2020] [Indexed: 11/25/2022] Open
Abstract
Goat plays a crucial role in human livelihoods, being a major source of meat, milk, fiber, and hides, particularly under adverse climatic conditions. The goat genomics related to the candidate gene approach is now being used to recognize molecular mechanisms that have different expressions of growth, reproductive, milk, wool, and disease resistance. The appropriate literature on this topic has been reviewed in this article. Several genetic characterization attempts of different goats have reported the existence of genotypic and morphological variations between different goat populations. As a result, different whole-genome sequences along with annotated gene sequences, gene function, and other genomic information of different goats are available in different databases. The main objective of this review is to search the genes associated with economic traits in goats. More than 271 candidate genes have been discovered in goats. Candidate genes influence the physiological pathway, metabolism, and expression of phenotypes. These genes have different functions on economically important traits. Some genes have pleiotropic effect for expression of phenotypic traits. Hence, recognizing candidate genes and their mutations that cause variations in gene expression and phenotype of an economic trait can help breeders look for genetic markers for specific economic traits. The availability of reference whole-genome assembly of goats, annotated genes, and transcriptomics makes comparative genomics a useful tool for systemic genetic upgradation. Identification and characterization of trait-associated sequence variations and gene will provide powerful means to give positive influences for future goat breeding program.
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Li T, Xu XH, Guo X, Yuan T, Tang ZH, Jiang XM, Xu YL, Zhang LL, Chen X, Zhu H, Shi JJ, Lu JJ. Activation of notch 3/c-MYC/CHOP axis regulates apoptosis and promotes sensitivity of lung cancer cells to mTOR inhibitor everolimus. Biochem Pharmacol 2020; 175:113921. [PMID: 32201213 DOI: 10.1016/j.bcp.2020.113921] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 03/17/2020] [Indexed: 02/06/2023]
Abstract
The mammalian target of rapamycin (mTOR) pathway converges diverse environmental cues to support the lung cancer growth and survival. However, the mTOR-targeted mono-therapy does not achieve expected therapeutic effect. Here, we revealed that fangchinoline (FCL), an active alkaloid that purified from the traditional Chinese medicine Stephania tetrandra S. Moore, enhanced the anti-lung cancer effect of mTOR inhibitor everolimus (EVE). The combination of EVE and FCL was effective to activate Notch 3, and subsequently evoked its downstream target c-MYC. The blockage of Notch 3 signal by the molecular inhibitor of γ-secretase or siRNA of Notch 3 reduced the c-MYC expression and attenuated the combinational efficacy of EVE and FCL on cell apoptosis and proliferation. Moreover, the c-MYC could bind to the C/EBP homologous protein (CHOP) promoter and facilitate CHOP transcription. The conditional genetic deletion of CHOP reduced the apoptosis on lung cancer cells to the same degree as blockage of Notch 3/c-MYC axis, providing further evidence for that the Notch 3/c-MYC axis regulates the transcription of CHOP and finally induces apoptosis upon co-treatment of FCL and EVE in lung cancer cells. Overall, our findings, to the best of our knowledge, firstly link CHOP to Notch 3/c-MYC axis-dependent apoptosis and provide the Notch 3/c-MYC/CHOP activation as a promising strategy for mTOR-targeted combination therapy in lung cancer treatment.
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Affiliation(s)
- Ting Li
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Xiao-Huang Xu
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Xia Guo
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Tao Yuan
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zheng-Hai Tang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Xiao-Ming Jiang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Yu-Lian Xu
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Le-Le Zhang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Xiuping Chen
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Hong Zhu
- Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jia-Jie Shi
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Jin-Jian Lu
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China.
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DNA methyltransferase inhibitors induce a BRCAness phenotype that sensitizes NSCLC to PARP inhibitor and ionizing radiation. Proc Natl Acad Sci U S A 2019; 116:22609-22618. [PMID: 31591209 DOI: 10.1073/pnas.1903765116] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
A minority of cancers have breast cancer gene (BRCA) mutations that confer sensitivity to poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis), but the role for PARPis in BRCA-proficient cancers is not well established. This suggests the need for novel combination therapies to expand the use of these drugs. Recent reports that low doses of DNA methyltransferase inhibitors (DNMTis) plus PARPis enhance PARPi efficacy in BRCA-proficient AML subtypes, breast, and ovarian cancer open up the possibility that this strategy may apply to other sporadic cancers. We identify a key mechanistic aspect of this combination therapy in nonsmall cell lung cancer (NSCLC): that the DNMTi component creates a BRCAness phenotype through downregulating expression of key homologous recombination and nonhomologous end-joining (NHEJ) genes. Importantly, from a translational perspective, the above changes in DNA repair processes allow our combinatorial PARPi and DNMTi therapy to robustly sensitize NSCLC cells to ionizing radiation in vitro and in vivo. Our combinatorial approach introduces a biomarker strategy and a potential therapy paradigm for treating BRCA-proficient cancers like NSCLC.
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7
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Chen Y, Li Y, Peng Y, Zheng X, Fan S, Yi Y, Zeng P, Chen H, Kang H, Zhang Y, Xiao ZX, Li C. ΔNp63α down-regulates c-Myc modulator MM1 via E3 ligase HERC3 in the regulation of cell senescence. Cell Death Differ 2018; 25:2118-2129. [PMID: 29880857 DOI: 10.1038/s41418-018-0132-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 04/20/2018] [Accepted: 05/08/2018] [Indexed: 12/31/2022] Open
Abstract
p63 and c-Myc are key transcription factors controlling genes involved in the cell cycle and cellular senescence. We previously reported that p63α can destabilize MM1 protein to derepress c-Myc, resulting in cell cycle progress and tumorigenesis. However, how the proteasomal degradation of MM1 is facilitated remains unclear. In the present study, we identified a novel E3 ligase, HERC3, which can mediate ubiquitination of MM1 and promote its proteasome-dependent degradation. We found that ΔNp63α transcriptionally up-regulates HERC3 and knockdown of HERC3 abrogates ΔNp63α-induced down-regulation of MM1. Either overexpression of MM1 or ablation of HERC3 induces cell senescence, while knockdown of MM1 rescues cell senescence induced by deficiency of either ΔNp63α or HERC3, implicating the involvement of the ΔNp63α/HERC3/MM1/c-Myc axis in the modulation of cell senescence. Additionally, our Oncomine analysis indicates activation of the ΔNp63α/HERC3/MM1/c-Myc axis in invasive breast carcinoma. Together, our data illuminate a novel axis regulating cell senescence: ΔNp63α stimulates transcription of E3 ligase HERC3, which mediates ubiquitination of c-Myc modulator MM1 and targets it to proteasomal degradation; subsequently, c-Myc is derepressed by ΔNp63α, thereby cell senescence is modulated by this axis. Our work provides a new interpretation of crosstalk between p63 and c-Myc, and also sheds new light on ΔNp63α-controlled cell senescence and tumorigenesis.
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Affiliation(s)
- Yonglong Chen
- Center of Growth, Metabolism and Aging, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, China
| | - Yimin Li
- Center of Growth, Metabolism and Aging, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, China
| | - Yougong Peng
- Department of General Surgery, The Second People's Hospital of Jingmen, Jingmen, 448000, Hubei, China
| | - Xuan Zheng
- Center of Growth, Metabolism and Aging, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, China
| | - Shijie Fan
- Center of Growth, Metabolism and Aging, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, China
| | - Yong Yi
- Center of Growth, Metabolism and Aging, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, China
| | - Peng Zeng
- Center of Growth, Metabolism and Aging, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, China
| | - Hu Chen
- Center of Growth, Metabolism and Aging, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, China
| | - Han Kang
- Center of Growth, Metabolism and Aging, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, China
| | - Yujun Zhang
- Center of Growth, Metabolism and Aging, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, China
| | - Zhi-Xiong Xiao
- Center of Growth, Metabolism and Aging, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, China
| | - Chenghua Li
- Center of Growth, Metabolism and Aging, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, Sichuan, China.
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8
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Cui F, Hou J, Huang C, Sun X, Zeng Y, Cheng H, Wang H, Li C. C-Myc regulates radiation-induced G2/M cell cycle arrest and cell death in human cervical cancer cells. J Obstet Gynaecol Res 2017; 43:729-735. [DOI: 10.1111/jog.13261] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 10/10/2016] [Accepted: 11/08/2016] [Indexed: 12/26/2022]
Affiliation(s)
- Fengmei Cui
- Department of Radiation Medicine, School of Radiation Medicine and Protection; Medical College of Soochow University; Suzhou China
- Collaborative Innovation Center of Radiation Medicine; Jiangsu Higher Education Institutions; Suzhou China
| | - Jun Hou
- Department of Pathology; Zhongshan Hospital, Fudan University; Shanghai China
| | - Chengcheng Huang
- Department of Radiation Medicine, School of Radiation Medicine and Protection; Medical College of Soochow University; Suzhou China
- Collaborative Innovation Center of Radiation Medicine; Jiangsu Higher Education Institutions; Suzhou China
| | - Xiujin Sun
- Department of Radiation Medicine, School of Radiation Medicine and Protection; Medical College of Soochow University; Suzhou China
- Collaborative Innovation Center of Radiation Medicine; Jiangsu Higher Education Institutions; Suzhou China
| | - Yanan Zeng
- Department of Radiation Medicine, School of Radiation Medicine and Protection; Medical College of Soochow University; Suzhou China
- Collaborative Innovation Center of Radiation Medicine; Jiangsu Higher Education Institutions; Suzhou China
| | - Huiying Cheng
- Department of Radiation Medicine, School of Radiation Medicine and Protection; Medical College of Soochow University; Suzhou China
- Collaborative Innovation Center of Radiation Medicine; Jiangsu Higher Education Institutions; Suzhou China
| | - Hao Wang
- Department of Oncology; the First Affiliated Hospital, Medical University of Anhui; Hefei China
| | - Chao Li
- Department of Radiotherapy and Oncology; Suzhou Kowloon Hospital, Shanghai Jiao Tong University School of Medicine; Suzhou China
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Vaughan L, Clarke PA, Barker K, Chanthery Y, Gustafson CW, Tucker E, Renshaw J, Raynaud F, Li X, Burke R, Jamin Y, Robinson SP, Pearson A, Maira M, Weiss WA, Workman P, Chesler L. Inhibition of mTOR-kinase destabilizes MYCN and is a potential therapy for MYCN-dependent tumors. Oncotarget 2016; 7:57525-57544. [PMID: 27438153 PMCID: PMC5295370 DOI: 10.18632/oncotarget.10544] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 06/01/2016] [Indexed: 02/07/2023] Open
Abstract
MYC oncoproteins deliver a potent oncogenic stimulus in several human cancers, making them major targets for drug development, but efforts to deliver clinically practical therapeutics have not yet been realized. In childhood cancer, aberrant expression of MYC and MYCN genes delineates a group of aggressive tumours responsible for a major proportion of pediatric cancer deaths. We designed a chemical-genetic screen that identifies compounds capable of enhancing proteasomal elimination of MYCN oncoprotein. We isolated several classes of compound that selectively kill MYCN expressing cells and we focus on inhibitors of PI3K/mTOR pathway in this study. We show that PI3K/mTOR inhibitors selectively killed MYCN-expressing neuroblastoma tumor cells, and induced significant apoptosis of transgenic MYCN-driven neuroblastoma tumors concomitant with elimination of MYCN protein in vivo. Mechanistically, the ability of these compounds to degrade MYCN requires complete blockade of mTOR but not PI3 kinase activity and we highlight NVP-BEZ235 as a PI3K/mTOR inhibitor with an ideal activity profile. These data establish that MYCN expression is a marker indicative of likely clinical sensitivity to mTOR inhibition, and provide a rationale for the selection of clinical candidate MYCN-destabilizers likely to be useful for the treatment of MYCN-driven cancers.
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Affiliation(s)
- Lynsey Vaughan
- Division of Clinical Studies, The Institute of Cancer Research, Sutton, Surrey, UK
- Present address: Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK
| | - Paul A. Clarke
- Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, Signal Transduction and Molecular Pharmacology Team, The Institute of Cancer Research, Sutton, Surrey, UK
| | - Karen Barker
- Division of Clinical Studies, The Institute of Cancer Research, Sutton, Surrey, UK
| | - Yvan Chanthery
- Department of Neurology, Pediatrics, Neurosurgery, Brain Tumor Research Center and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - Clay W. Gustafson
- Department of Neurology, Pediatrics, Neurosurgery, Brain Tumor Research Center and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - Elizabeth Tucker
- Division of Clinical Studies, The Institute of Cancer Research, Sutton, Surrey, UK
| | - Jane Renshaw
- Division of Clinical Studies, The Institute of Cancer Research, Sutton, Surrey, UK
| | - Florence Raynaud
- Cancer Research UK Cancer Therapeutics Unit, Clinical Pharmacology and Trials Team, Sutton, Surrey, UK
| | - Xiaodun Li
- Division of Clinical Studies, The Institute of Cancer Research, Sutton, Surrey, UK
- Present address: MRC Cancer Unit, University of Cambridge, Cambridge, UK
| | - Rosemary Burke
- Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, Target Selection and Hit Discovery Team, The Institute of Cancer Research, Sutton, Surrey, UK
| | - Yann Jamin
- Cancer Research UK & Engineering and Physical Sciences Research Council Cancer Imaging Centre, The Institute of Cancer Research, Sutton, Surrey, UK
| | - Simon P. Robinson
- Cancer Research UK & Engineering and Physical Sciences Research Council Cancer Imaging Centre, The Institute of Cancer Research, Sutton, Surrey, UK
| | - Andrew Pearson
- Division of Clinical Studies, The Institute of Cancer Research, Sutton, Surrey, UK
| | - Michel Maira
- Novartis Pharma AG, Basel, Switzerland
- Present address: Basilea Pharmaceutica International AG, Basel, Switzerland
| | - William A. Weiss
- Department of Neurology, Pediatrics, Neurosurgery, Brain Tumor Research Center and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - Paul Workman
- Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, Signal Transduction and Molecular Pharmacology Team, The Institute of Cancer Research, Sutton, Surrey, UK
| | - Louis Chesler
- Division of Clinical Studies, The Institute of Cancer Research, Sutton, Surrey, UK
- Cancer Research UK Cancer Therapeutics Unit, The Institute of Cancer Research, Signal Transduction and Molecular Pharmacology Team, The Institute of Cancer Research, Sutton, Surrey, UK
- The Royal Marsden NHS Trust, Children and Young People's Unit, Sutton, Surrey, UK
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10
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Abstract
Apoptosis is a regulated form of cell death that proceeds by defined biochemical pathways. Most apoptosis is controlled by interactions between pro-survival and pro-apoptotic Bcl-2 family proteins in which death is often the consequence of permeabilization of the mitochondrial outer membrane. Many drugs affect this equilibrium to favor apoptosis but this process is not completely understood. We show that the chemotherapeutic drug cisplatin initiates an apoptotic pathway by phosphorylation of a pro-survival Bcl-2 family member, Bcl-xL, by cyclin-dependent kinase 2. The phosphorylation occurred at a previously unreported site and its biologic significance was demonstrated by a phosphomimetic modification of Bcl-xL that was able to induce apoptosis without addition of cisplatin. The mechanism of cell death induction was similar to that initiated by pro-apoptotic Bcl-2 family proteins, that is, phosphorylated Bcl-xL translocated to the mitochondrial membrane, and formed pores in the membrane. This initiated cytochrome c release and caspase activation that resulted in cell death.
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11
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Cui F, Fan R, Chen Q, He Y, Song M, Shang Z, Zhang S, Zhu W, Cao J, Guan H, Zhou PK. The involvement of c-Myc in the DNA double-strand break repair via regulating radiation-induced phosphorylation of ATM and DNA-PKcs activity. Mol Cell Biochem 2015; 406:43-51. [PMID: 26049366 DOI: 10.1007/s11010-015-2422-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 04/20/2015] [Indexed: 10/23/2022]
Abstract
Deregulation of c-Myc often occurs in various human cancers, which not only contributes to the genesis and progression of cancers but also affects the outcomes of cancer radio- or chemotherapy. In this study, we have investigated the function of c-Myc in the repair of DNA double-strand break (DSB) induced by γ-ray irradiation. A c-Myc-silenced Hela-630 cell line was generated from HeLa cells using RNA interference technology. The DNA DSBs were detected by γ-H2AX foci, neutral comet assay and pulsed-field gel electrophoresis. We found that the capability of DNA DSB repair in Hela-630 cells was significantly reduced, and the repair kinetics of DSB was delayed as compared to the control Hela-NC cells. Silence of c-myc sensitized the cellular sensitivity to ionizing radiation. The phosphorylated c-Myc (Thr58/pSer62) formed the consistent co-localisation foci with γ-H2AX as well as the phosphorylated DNA-PKcs/S2056 in the irradiated cells. Moreover, depression of c-Myc largely attenuated the ionizing radiation-induced phosphorylation of the ataxia telangiectasia mutated (ATM) and decreased the in vitro kinase activity of DNA-PKcs. Taken together, our results demonstrated that c-Myc protein functions in the process of DNA double-strand break repair, at least partially, through affecting the ATM phosphorylation and DNA-PKcs kinase activity. The overexpression of c-Myc in tumours can account for the radioresistance of some tumour cell types.
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Affiliation(s)
- Fengmei Cui
- Department of Radiation Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, 215123, China
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12
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Wirth M, Stojanovic N, Christian J, Paul MC, Stauber RH, Schmid RM, Häcker G, Krämer OH, Saur D, Schneider G. MYC and EGR1 synergize to trigger tumor cell death by controlling NOXA and BIM transcription upon treatment with the proteasome inhibitor bortezomib. Nucleic Acids Res 2014; 42:10433-47. [PMID: 25147211 PMCID: PMC4176343 DOI: 10.1093/nar/gku763] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The c-MYC (MYC afterward) oncogene is well known for driving numerous oncogenic programs. However, MYC can also induce apoptosis and this function of MYC warrants further clarification. We report here that a clinically relevant proteasome inhibitor significantly increases MYC protein levels and that endogenous MYC is necessary for the induction of apoptosis. This kind of MYC-induced cell death is mediated by enhanced expression of the pro-apoptotic BCL2 family members NOXA and BIM. Quantitative promoter-scanning chromatin immunoprecipitations (qChIP) further revealed binding of MYC to the promoters of NOXA and BIM upon proteasome inhibition, correlating with increased transcription. Both promoters are further characterized by the presence of tri-methylated lysine 4 of histone H3, marking active chromatin. We provide evidence that in our apoptosis models cell death occurs independently of p53 or ARF. Furthermore, we demonstrate that recruitment of MYC to the NOXA as well as to the BIM gene promoters depends on MYC's interaction with the zinc finger transcription factor EGR1 and an EGR1-binding site in both promoters. Our study uncovers a novel molecular mechanism by showing that the functional cooperation of MYC with EGR1 is required for bortezomib-induced cell death. This observation may be important for novel therapeutic strategies engaging the inherent pro-death function of MYC.
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Affiliation(s)
- Matthias Wirth
- Medizinische Klinik, Technische Universität München, München 81675, Germany
| | - Natasa Stojanovic
- Medizinische Klinik, Technische Universität München, München 81675, Germany
| | - Jan Christian
- Departments of Medicine and of Microbiology and Immunology, The Research Institute of the McGill University Health Centre, McGill University, Montréal H3A 2B4, Canada
| | - Mariel C Paul
- Medizinische Klinik, Technische Universität München, München 81675, Germany
| | - Roland H Stauber
- Molecular and Cellular Oncology/Mainz Screening Center (MSC), University Hospital of Mainz, Mainz 55101, Germany
| | - Roland M Schmid
- Medizinische Klinik, Technische Universität München, München 81675, Germany
| | - Georg Häcker
- Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinik Freiburg, Freiburg 79104, Germany
| | - Oliver H Krämer
- Department of Toxicology, University of Mainz Medical Center, Mainz 55131, Germany
| | - Dieter Saur
- Medizinische Klinik, Technische Universität München, München 81675, Germany
| | - Günter Schneider
- Medizinische Klinik, Technische Universität München, München 81675, Germany
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Xie C, Pan Y, Hao F, Gao Y, Liu Z, Zhang X, Xie L, Jiang G, Li Q, Wang E. C-Myc participates in β-catenin-mediated drug resistance in A549/DDP lung adenocarcinoma cells. APMIS 2014; 122:1251-8. [PMID: 25131138 DOI: 10.1111/apm.12296] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 05/26/2014] [Indexed: 11/28/2022]
Abstract
The aim of this study was to investigate c-Myc and β-catenin-mediated drug resistance in A549/DDP lung adenocarcinoma cells. Cisplatin sensitivity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) toxicity assay. β-Catenin and c-Myc protein expression following cisplatin treatment were determined using western blotting and immunofluorescence. Flow cytometry was performed to detect cell cycle and apoptosis in A549, A549/DDP, and c-Myc small interfering RNA (siRNA)-transfected A549/DDP cells before and after treatment with different doses of cisplatin. The median inhibitory concentration (IC50 ) in cisplatin-treated A549 and A549/DDP cells was 5.769 ± 0.24 μmol/L and 28.373 ± 0.96 μmol/L, respectively; the cisplatin resistance of A549 cells was about five times that of A549/DDP cells. Endogenous β-catenin and c-Myc expression in A549/DDP cells were higher than that in A549 cells, and were upregulated in A549/DDP cells (p < 0.05) and downregulated in A549 cells after 48 h cisplatin treatment (p < 0.05). β-catenin localization transferred from membrane/cytoplasmic/nuclear to cytoplasmic/nuclear, and c-Myc localization transferred from cytoplasmic/nuclear to nuclear in both cell lines following cisplatin treatment. The rate of apoptosis increased in a dose-dependent manner with cisplatin. After 48-h transfection with c-myc siRNA, A549/DDP cells were blocked in the S phase, and G0/G1-phase cells increased. Simultaneously, the apoptotic rate was increased (p < 0.05) and the IC50 decreased significantly (p < 0.05). C-myc, the downstream target gene of β-catenin, plays an important role in regulating cisplatin resistance in A549/DDP cells. C-Myc siRNA improved the sensitivity of A549/DDP cells to cisplatin.
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Affiliation(s)
- Chengyao Xie
- Department of Pathology, The First Affiliated Hospital and College of Basic Medical Sciences of China Medical University, Shenyang, China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang, China
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14
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Xie Y, Zhang J, Xu Y, Shao C. SirT1 confers hypoxia-induced radioresistance via the modulation of c-Myc stabilization on hepatoma cells. JOURNAL OF RADIATION RESEARCH 2012; 53:44-50. [PMID: 22302044 DOI: 10.1269/jrr.11062] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Intratumoral hypoxia is an important contributory factor to tumor cell resistance to radiotherapy. SirT1, a nicotinamide adenine dinucleotide (NAD(+))-dependent histone/protein deacetylase, has been linked to the decrease of radiation-induced DNA damage and seems to be critical for cancer therapy. The purpose of this study was to investigate the role of SirT1 in hypoxia-induced radiation response on hepatoma cells. It was found that the administration with resveratrol, a putative SirT1 activator, enhanced the resistance of HepG2 cells against radiation-induced DNA damage of MN formation under hypoxia condition; while nicotinamide, a well-known SirT1 inhibitor, sensitized this radiation damage. Nevertheless, pretreatment of cells with 10058-F4, a specific inhibitor of c-Myc, almost eliminated the nicotinamide-induced radiosensitive effect. Further studies revealed that resveratrol inhibited c-Myc protein accumulation via up-regulation of SirT1 expression and deacetylase activity, and this loss of c-Myc protein was abolished by inhibiting its degradation in the presence of MG132, a potent inhibitor of proteasome. In contrast, nicotinamide attenuated c-Myc protein degradation induced by radiation under hypoxia through inhibition of SirT1 deacetylase activity. Our findings suggest that SirT1 could serve as a novel potent target of radiation-induced DNA damage and thus as a potential strategy to advance the efficiency of radiation therapy in hepatoma entities.
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Affiliation(s)
- Yuexia Xie
- Department of Radiation Biology, Institute of Radiation Medicine, Fudan University, Shanghai, China
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15
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Thariat J, Italiano A, Collin F, Iannessi A, Marcy PY, Lacout A, Birtwisle-Peyrottes I, Thyss A, Lagrange JL. Not all sarcomas developed in irradiated tissue are necessarily radiation-induced--spectrum of disease and treatment characteristics. Crit Rev Oncol Hematol 2011; 83:393-406. [PMID: 22138059 DOI: 10.1016/j.critrevonc.2011.11.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 10/24/2011] [Accepted: 11/10/2011] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Sarcomas in irradiated tissue (SITs) are often considered with second cancers, although they usually present distinct dose-response, genetic and clinical patterns. The contribution of radiation in SIT development is likely, but remains unproven in many cases. MATERIALS AND METHODS We reviewed the literature for published data on SITs. RESULTS SITs incidence ranged between 0.03% and 0.2%. Median latency was 15 years. Angiosarcoma was the second most common subtype after undifferentiated sarcomas of malignant fibrous histiocytoma (MFH). C-Myc overexpression can be used to identify radiation-induced angiosarcoma, and a recently described transcriptomic signature of genes involved in chronic oxidative stress and mitochondrial dysfunction may indicate radiation causality. Osteosarcomas were often associated with genetic predisposition. Five-year survival rates rarely exceeded 30% because the therapeutic possibilities were often limited by the first cancer. Chemotherapy response may differ from that of de novo sarcomas. CONCLUSION SITs present different characteristics from non-sarcomatoid second cancers. Reporting of SIT cases and the establishment of tissue and serum banks is necessary to better understand and validate the recently discovered radiation signature.
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Affiliation(s)
- Juliette Thariat
- Department of Radiation Oncology/IBDC CNRS UMR 6543 Institut Universitaire de la Face et du Cou, Antoine-Lacassagne Cancer Center, Nice Sophia-Antipolis University, 33 Av. Valombrose, 06189 Nice Cedex 2, France.
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Italiano A, Cioffi A, Penel N, Levra MG, Delcambre C, Kalbacher E, Chevreau C, Bertucci F, Isambert N, Blay JY, Bui B, Antonescu C, D'Adamo DR, Maki RG, Keohan ML. Comparison of doxorubicin and weekly paclitaxel efficacy in metastatic angiosarcomas. Cancer 2011; 118:3330-6. [PMID: 22045619 DOI: 10.1002/cncr.26599] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 07/06/2011] [Accepted: 07/11/2011] [Indexed: 12/13/2022]
Abstract
BACKGROUND Data regarding the role of anthracyclines and taxanes as first-line treatments of metastatic angiosarcoma are limited. METHODS Records of 117 metastatic angiosarcoma patients who were treated with either doxorubicin or weekly paclitaxel were reviewed. RESULTS Seventy-five patients (64%) were treated with weekly paclitaxel and 42 (36%) with single-agent doxorubicin. Patients in the weekly paclitaxel group were older and more frequently had angiosarcomas arising from the skin. In the doxorubicin group, 34 patients were evaluable for response: 2 (6%) had complete response, 8 (23.5%) had partial response, 10 (29.5%) had stable disease, and 14 (41%) had progressive disease. In the weekly paclitaxel group, 68 patients were evaluable for response: 9 (13%) had complete response, 27 (40%) had partial response, 20 (29.5%) had stable disease, and 12 (17.5%) had progressive disease. Objective responses to weekly paclitaxel were more frequent in cutaneous angiosarcomas, whereas tumor location did not impact response to doxorubicin. Median progression-free survival (PFS) was 4.9 months (95% confidence interval [95% CI], 3.9-6.0 months). Median overall survival (OS) was 8.5 months (95% CI, 6.4-10.7 months). On multivariate analysis, ECOG performance status (PS) was the sole independent factor associated with PFS and OS. CONCLUSIONS First-line single-agent doxorubicin and weekly paclitaxel seem to have similar efficacy in metastatic angiosarcomas. Cutaneous angiosarcomas respond favorably to weekly paclitaxel. Best supportive care should be considered in patients with poor PS.
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Affiliation(s)
- Antoine Italiano
- Department of Medical Oncology, Institut Bergonié, Bordeaux, France.
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Lee HP, Kudo W, Zhu X, Smith MA, Lee HG. Early induction of c-Myc is associated with neuronal cell death. Neurosci Lett 2011; 505:124-7. [PMID: 22005580 DOI: 10.1016/j.neulet.2011.10.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 09/01/2011] [Accepted: 10/02/2011] [Indexed: 10/16/2022]
Abstract
Neuronal cell cycle activation has been implicated in neurodegenerative diseases such as Alzheimer's disease, while the initiating mechanism of cell cycle activation remains to be determined. Interestingly, our previous studies have shown that cell cycle activation by c-Myc (Myc) leads to neuronal cell death which suggests Myc might be a key regulator of cell cycle re-entry mediated neuronal cell death. However, the pattern of Myc expression in the process of neuronal cell death has not been addressed. To this end, we examined Myc induction by the neurotoxic agents camptothecin and amyloid-β peptide in a differentiated SH-SY5Y neuronal cell culture model. Myc expression was found to be significantly increased following either treatment and importantly, the induction of Myc preceded neuronal cell death suggesting it is an early event of neuronal cell death. Since ectopic expression of Myc in neurons causes the cell cycle activation and neurodegeneration in vivo, the current data suggest that induction of Myc by neurotoxic agents or other disease factors might be a key mediator in cell cycle activation and consequent cell death that is a feature of neurodegenerative diseases.
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Affiliation(s)
- Hyun-Pil Lee
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
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18
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De Salvo M, Maresca G, D'agnano I, Marchese R, Stigliano A, Gagliassi R, Brunetti E, Raza GH, De Paula U, Bucci B. Temozolomide induced c-Myc-mediated apoptosis via Akt signalling in MGMT expressing glioblastoma cells. Int J Radiat Biol 2011; 87:518-33. [PMID: 21405945 DOI: 10.3109/09553002.2011.556173] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
PURPOSE We investigated the molecular mechanisms underlying the cytotoxic effect of Temozolomide (TMZ) in both O(6)-methylguanine-DNA methyl transferase (MGMT) depleted as well as undepleted glioblastoma cell lines. Since TMZ is used in clinics in combination with radiotherapy, we also studied the effects of TMZ in combination with ionising radiation (IR). METHODS Cell colony-forming ability was measured using a clonogenic assay. Cell cycle analysis and apoptosis were evaluated by Flow Cytometry (FCM). Proteins involved in cell cycle control were detected by Western blot and co-immunoprecipitation assays. RESULTS Our data showed that TMZ, independent of MGMT expression, inhibited glioblastoma cell growth via an irreversible G(2) block in MGMT depleted cells or the induction of apoptosis in MGMT normal expressing cells. When TMZ was administered in combination with IR, apoptosis was greater than observed with either agent separately. This TMZ-induced apoptosis in the MGMT expressing cells occurred through Akt/Glycogen-Synthase-Kinase-3ß (GSK3ß) signalling and was mediated by Myelocytomatosis (c-Myc) oncoprotein. Indeed, TMZ phosphorylated/activated Akt led to phosphorylation/inactivation of GSK3ß which resulted in the stabilisation of c-Myc protein and subsequent modulation of the c-Myc target genes involved in the apoptotic processes. CONCLUSION C-Myc expression could be considered a good indicator of TMZ effectiveness.
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Affiliation(s)
- Maria De Salvo
- Centro Ricerca S. Pietro, Fatebenefratelli Hospital, Via Cassia 600, Rome, Italy
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Shukla V, Cuenin C, Dubey N, Herceg Z. Loss of histone acetyltransferase cofactor transformation/transcription domain-associated protein impairs liver regeneration after toxic injury. Hepatology 2011; 53:954-63. [PMID: 21319192 DOI: 10.1002/hep.24120] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 12/02/2010] [Indexed: 01/12/2023]
Abstract
Organ regeneration after toxin challenge or physical injury requires a prompt and balanced cell-proliferative response; a well-orchestrated cascade of gene expression is needed to regulate transcription factors and proteins involved in cell cycle progression and cell proliferation. After liver injury, cell cycle entry and progression of hepatocytes are believed to require concerted efforts of transcription factors and histone-modifying activities; however, the actual underlying mechanisms remain largely unknown. The purpose of our study was to investigate the role of the histone acetyltransferase (HAT) cofactor transformation/transcription domain-associated protein (TRRAP) and histone acetylation in the regulation of cell cycle and liver regeneration. To accomplish our purpose, we used a TRRAP conditional knockout mouse model combined with toxin-induced hepatic injury. After we treated the mice with a carbon tetrachloride toxin, conditional ablation of the TRRAP gene in those mice severely impaired liver regeneration and compromised cell cycle entry and progression of hepatocytes. Furthermore, loss of TRRAP impaired the induction of early and late cyclins in regenerating livers by compromising histone acetylation and transcription factor binding at the promoters of the cyclin genes. Our results demonstrate that TRRAP and TRRAP/HAT-mediated acetylation play an important role in liver regeneration after toxic injury and provide insight into the mechanism by which TRRAP/HATs orchestrate the expression of the cyclin genes during cell cycle entry and progression.
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Affiliation(s)
- Vivek Shukla
- International Agency for Research on Cancer (IARC), Lyon, France.
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20
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von Bueren AO, Oehler C, Shalaby T, von Hoff K, Pruschy M, Seifert B, Gerber NU, Warmuth-Metz M, Stearns D, Eberhart CG, Kortmann RD, Rutkowski S, Grotzer MA. c-MYC expression sensitizes medulloblastoma cells to radio- and chemotherapy and has no impact on response in medulloblastoma patients. BMC Cancer 2011; 11:74. [PMID: 21324178 PMCID: PMC3050852 DOI: 10.1186/1471-2407-11-74] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 02/16/2011] [Indexed: 12/27/2022] Open
Abstract
Background To study whether and how c-MYC expression determines response to radio- and chemotherapy in childhood medulloblastoma (MB). Methods We used DAOY and UW228 human MB cells engineered to stably express different levels of c-MYC, and tested whether c-MYC expression has an effect on radio- and chemosensitivity using the colorimetric 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt (MTS) assay, clonogenic survival, apoptosis assays, cell cycle analysis, and western blot assessment. In an effort to validate our results, we analyzed c-MYC mRNA expression in formalin-fixed paraffin-embedded tumor samples from well-documented patients with postoperative residual tumor and compared c-MYC mRNA expression with response to radio- and chemotherapy as examined by neuroradiological imaging. Results In DAOY - and to a lesser extent in UW228 - cells expressing high levels of c-MYC, the cytotoxicity of cisplatin, and etoposide was significantly higher when compared with DAOY/UW228 cells expressing low levels of c-MYC. Irradiation- and chemotherapy-induced apoptotic cell death was enhanced in DAOY cells expressing high levels of c-MYC. The response of 62 of 66 residual tumors was evaluable and response to postoperative radio- (14 responders (CR, PR) vs. 5 non-responders (SD, PD)) or chemotherapy (23 CR/PR vs. 20 SD/PD) was assessed. c-MYC mRNA expression was similar in primary MB samples of responders and non-responders (Mann-Whitney U test, p = 0.50, ratio 0.49, 95% CI 0.008-30.0 and p = 0.67, ratio 1.8, 95% CI 0.14-23.5, respectively). Conclusions c-MYC sensitizes MB cells to some anti-cancer treatments in vitro. As we failed to show evidence for such an effect on postoperative residual tumors when analyzed by imaging, additional investigations in xenografts and larger MB cohorts may help to define the exact function of c-MYC in modulating response to treatment.
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Affiliation(s)
- André O von Bueren
- Neuro-Oncology Program, University Children's Hospital, Zurich, Switzerland.
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Nasu K, Nishida M, Kawano Y, Tsuno A, Abe W, Yuge A, Takai N, Narahara H. Aberrant expression of apoptosis-related molecules in endometriosis: a possible mechanism underlying the pathogenesis of endometriosis. Reprod Sci 2010; 18:206-18. [PMID: 21193803 DOI: 10.1177/1933719110392059] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Endometriosis, a disease affecting 3% to 10% of women of reproductive age, is characterized by the ectopic growth of endometrial tissue under the influence of estrogen. It is also becoming recognized as a condition in which ectopic endometrial cells exhibit abnormal proliferative and apoptotic regulation in response to appropriate stimuli. Apoptosis plays a critical role in maintaining tissue homeostasis and represents a normal function to eliminate excess or dysfunctional cells. Accumulated evidence suggests that, in healthy women, endometrial cells expelled during menstruation do not survive in ectopic locations because of programmed cell death, while decreased apoptosis may lead to the ectopic survival and implantation of these cells, resulting in the development of endometriosis. Both the inability of endometrial cells to transmit a "death" signal and the ability of endometrial cells to avoid cell death have been associated with increased expression of antiapoptotic factors and decreased expression of preapoptotic factors. Further investigations may elucidate the role of apoptosis-associated molecules in the pathogenesis of endometriosis. Medical treatment with apoptosis-inducing agents may be novel and promising therapeutic strategy for endometriosis.
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Affiliation(s)
- Kaei Nasu
- Department of Obstetrics and Gynecology, Faculty of Medicine, Oita University, Oita, Japan.
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22
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Albihn A, Johnsen JI, Henriksson MA. MYC in oncogenesis and as a target for cancer therapies. Adv Cancer Res 2010; 107:163-224. [PMID: 20399964 DOI: 10.1016/s0065-230x(10)07006-5] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
MYC proteins (c-MYC, MYCN, and MYCL) regulate processes involved in many if not all aspects of cell fate. Therefore, it is not surprising that the MYC genes are deregulated in several human neoplasias as a result from genetic and epigenetic alterations. The near "omnipotency" together with the many levels of regulation makes MYC an attractive target for tumor intervention therapy. Here, we summarize some of the current understanding of MYC function and provide an overview of different cancer forms with MYC deregulation. We also describe available treatments and highlight novel approaches in the pursuit for MYC-targeting therapies. These efforts, at different stages of development, constitute a promising platform for novel, more specific treatments with fewer side effects. If successful a MYC-targeting therapy has the potential for tailored treatment of a large number of different tumors.
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Affiliation(s)
- Ami Albihn
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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23
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Guerra L, Albihn A, Tronnersjö S, Yan Q, Guidi R, Stenerlöw B, Sterzenbach T, Josenhans C, Fox JG, Schauer DB, Thelestam M, Larsson LG, Henriksson M, Frisan T. Myc is required for activation of the ATM-dependent checkpoints in response to DNA damage. PLoS One 2010; 5:e8924. [PMID: 20111719 PMCID: PMC2811743 DOI: 10.1371/journal.pone.0008924] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 01/05/2010] [Indexed: 01/20/2023] Open
Abstract
Background The MYC protein controls cellular functions such as differentiation, proliferation, and apoptosis. In response to genotoxic agents, cells overexpressing MYC undergo apoptosis. However, the MYC-regulated effectors acting upstream of the mitochondrial apoptotic pathway are still unknown. Principal Findings In this study, we demonstrate that expression of Myc is required to activate the Ataxia telangiectasia mutated (ATM)-dependent DNA damage checkpoint responses in rat cell lines exposed to ionizing radiation (IR) or the bacterial cytolethal distending toxin (CDT). Phosphorylation of the ATM kinase and its downstream effectors, such as histone H2AX, were impaired in the myc null cell line HO15.19, compared to the myc positive TGR-1 and HOmyc3 cells. Nuclear foci formation of the Nijmegen Breakage Syndrome (Nbs) 1 protein, essential for efficient ATM activation, was also reduced in absence of myc. Knock down of the endogenous levels of MYC by siRNA in the human cell line HCT116 resulted in decreased ATM and CHK2 phosphorylation in response to irradiation. Conversely, cell death induced by UV irradiation, known to activate the ATR-dependent checkpoint, was similar in all the cell lines, independently of the myc status. Conclusion These data demonstrate that MYC contributes to the activation of the ATM-dependent checkpoint responses, leading to cell death in response to specific genotoxic stimuli.
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Affiliation(s)
- Lina Guerra
- Departments of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Ami Albihn
- Departments of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Susanna Tronnersjö
- Departments of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Qinzi Yan
- Departments of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Riccardo Guidi
- Departments of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Bo Stenerlöw
- Division of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Torsten Sterzenbach
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Christine Josenhans
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - James G. Fox
- Department of Biological Engineering, Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - David B. Schauer
- Department of Biological Engineering, Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Monica Thelestam
- Departments of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Lars-Gunnar Larsson
- Departments of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Marie Henriksson
- Departments of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Teresa Frisan
- Departments of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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Li ZX, Ouyang KQ, Jiang X, Wang D, Hu Y. Curcumin induces apoptosis and inhibits growth of human Burkitt's lymphoma in xenograft mouse model. Mol Cells 2009; 27:283-9. [PMID: 19326074 DOI: 10.1007/s10059-009-0036-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 12/08/2008] [Accepted: 12/19/2008] [Indexed: 10/21/2022] Open
Abstract
Curcumin, a natural compound extracted from rhizomes of curcuma Curcuma species, has been shown to possess potent anti-inflammatory, anti-tumor and anti-oxidative properties. However, the mechanism of action of the compound remains poorly understood. In this report, we have analyzed the effects of curcumin on the cell proliferation of Burkitt's lymphoma Raji cells. The results demonstrated that curcumin could effectively inhibit the growth of Raji cells in a dose- and time-dependent manner. Further studies indicated that curcumin treatment resulted in apoptosis of cells. Biochemical analysis showed that the expression of Bax, Bid and cytochrome C were up-regulated, while the expression of oncogene c-Myc was down regulated after curcumin treatment. Furthermore, poly (ADP-ribose) polymerase (PARP) cleavage was induced by the compound. Interestingly, the antiapoptotic Bcl-2 expression was not significantly changed in Raji cells after curcumin treatment. These results suggested that the mechanism of action of curcumin was to induce mitochondrial damage and therefore led to Raji cell apoptosis. We further investigated the in vivo effects of curcumin on the growth of xenograft tumors in nude mice. The results showed that curcumin could effectively inhibit tumor growth in the xenograft mouse model. The overall results showed that curcumin could suppress the growth of Burkitt's lymphoma cells in both in vitro and in vitro systems.
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Affiliation(s)
- Zai-xin Li
- College of Bioengineering, Chongqing University, Chongqing 400044, China
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RNA interference-mediated c-MYC inhibition prevents cell growth and decreases sensitivity to radio- and chemotherapy in childhood medulloblastoma cells. BMC Cancer 2009; 9:10. [PMID: 19134217 PMCID: PMC2648994 DOI: 10.1186/1471-2407-9-10] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Accepted: 01/10/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND With current treatment strategies, nearly half of all medulloblastoma (MB) patients die from progressive tumors. Accordingly, the identification of novel therapeutic strategies remains a major goal. Deregulation of c-MYC is evident in numerous human cancers. In MB, over-expression of c-MYC has been shown to cause anaplasia and correlate with unfavorable prognosis. METHODS To study the role of c-MYC in MB biology, we down-regulated c-MYC expression by using small interfering RNA (siRNA) and investigated changes in cellular proliferation, cell cycle analysis, apoptosis, telomere maintenance, and response to ionizing radiation (IR) and chemotherapeutics in a representative panel of human MB cell lines expressing different levels of c-MYC (DAOY wild-type, DAOY transfected with the empty vector, DAOY transfected with c-MYC, D341, and D425). RESULTS siRNA-mediated c-MYC down-regulation resulted in an inhibition of cellular proliferation and clonogenic growth, inhibition of G1-S phase cell cycle progression, and a decrease in human telomerase reverse transcriptase (hTERT) expression and telomerase activity. On the other hand, down-regulation of c-MYC reduced apoptosis and decreased the sensitivity of human MB cells to IR, cisplatin, and etoposide. This effect was more pronounced in DAOY cells expressing high levels of c-MYC when compared with DAOY wild-type or DAOY cells transfected with the empty vector. CONCLUSION In human MB cells, in addition to its roles in growth and proliferation, c-MYC is also a potent inducer of apoptosis. Therefore, targeting c-MYC might be of therapeutic benefit when used sequentially with chemo- and radiotherapy rather than concomitantly.
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Abstract
Just over 25 years ago, MYC, the human homologue of a retroviral oncogene, was identified. Since that time, MYC research has been intense and the advances impressive. On reflection, it is astonishing how each incremental insight into MYC regulation and function has also had an impact on numerous biological disciplines, including our understanding of molecular oncogenesis in general. Here we chronicle the major advances in our understanding of MYC biology, and peer into the future of MYC research.
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Morandi E, Severini C, Quercioli D, D'Ario G, Perdichizzi S, Capri M, Farruggia G, Mascolo MG, Horn W, Vaccari M, Serra R, Colacci A, Silingardi P. Gene expression time-series analysis of camptothecin effects in U87-MG and DBTRG-05 glioblastoma cell lines. Mol Cancer 2008; 7:66. [PMID: 18694480 PMCID: PMC2556695 DOI: 10.1186/1476-4598-7-66] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Accepted: 08/11/2008] [Indexed: 11/25/2022] Open
Abstract
Background The clinical efficacy of camptothecin (CPT), a drug specifically targeting topoisomerase I (TopoI), is under evaluation for the treatment of malignant gliomas. Due to the high unresponsiveness of these tumours to chemotherapy, it would be very important to study the signalling network that drives camptothecin outcome in this type of cancer cells. To address this issue, we had previously compared the expression profile of human U87-MG glioblastoma cells with that of a CPT-resistant counterpart, giving evidence that the development of a robust inflammatory response was the main transcriptional effect associated with CPT resistance. Here we report time-related changes and cell line specific patterns of gene expression after CPT treatment by using two p53 wild-type glioblastoma cell lines, U87-MG and DBTRG-05, with different sensitivities to TopoI inhibition. Results First, we demonstrated that CPT treatment brings the two cell lines to completely different outcomes: accelerated senescence in U87-MG and apoptosis in DBTRG-05 cells. Then, to understand the different susceptibility to CPT, we used oligo-microarray to identify the genes whose expression was regulated during a time-course treatment, ranging from 2 h to 72 h. The statistical analysis of microarray data by MAANOVA (MicroArray ANalysis Of VAriance) showed much less modulated genes in apoptotic DBTRG-05 cells (155) with respect to the senescent U87-MG cells (3168), where the number of down-regulated genes largely exceeded that of the up-regulated ones (80% vs. 20%). Despite this great difference, the two data-sets showed a large overlapping (60% circa) mainly due to the expression of early stress responsive genes. The use of High-Throughput GoMINER and EASE tools, for functional analysis of significantly enriched GO terms, highlighted common cellular processes and showed that U87-MG and DBTRG-05 cells shared many GO terms, which are related to the down-regulation of cell cycle and mitosis and to the up-regulation of cell growth inhibition and DNA damage. Furthermore, the down-regulation of MYC and DP1 genes, which act as key transcription factors in cell growth control, together with the inhibition of BUB1, BUB3 and MAD2 mRNAs, which are known to be involved in the spindle checkpoint pathway, were specifically associated with the execution of senescence in U87-MG cells and addressed as critical factors that could drive the choice between different CPT-inducible effectors programs. In U87-MG cells we also found inflammation response and IL1-beta induction, as late transcriptional effects of Topo I treatment but these changes were only partially involved in the senescence development, as shown by IL1-beta gene silencing. Conclusion By comparing the transcription profile of two glioblastoma cell lines treated with camptothecin, we were able to identify the common cellular pathways activated upon Topo I inhibition. Moreover, our results helped in identifying some key genes whose expression seemed to be associated with the execution of senescence or apoptosis in U87-MG and DBTRG-05 cells, respectively.
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Affiliation(s)
- Elena Morandi
- Excellence Environmental Carcinogenesis, Lab, Mater, Environmental Protection and Health Prevention Agency, Emilia-Romagna Region EPA, Bologna County, Italy.
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Mana-Hox displays anticancer activity against prostate cancer cells through tubulin depolymerization and DNA damage stress. Naunyn Schmiedebergs Arch Pharmacol 2008; 378:599-608. [PMID: 18663430 DOI: 10.1007/s00210-008-0330-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Accepted: 06/25/2008] [Indexed: 12/15/2022]
Abstract
Tubulin and deoxyribonucleic acid (DNA) are two potential targets for the development of cancer chemotherapeutic agents. Mana-Hox is a synthetic derivative of beta-carboline, a structure relevant to marine sponge component, manzamine. In this study, Mana-Hox induced an inhibition of cell proliferation in several types of human cancer cell lines, including androgen-independent prostate cancer PC-3 and DU-145, hepatocellular carcinoma Hep3B and HepG2, and colorectal cancer HT-29 cells. The p53-null PC-3 cells were used for to anticancer mechanisms. Mana-Hox stimulated an increase of ataxia telangiectasia mutated (ATM) phosphorylation on Ser-1981, indicating the induction of DNA double-strand breaks. It also displayed an inhibitory effect on tubulin polymerization using tubulin turbidity assay and immunofluorescence identification. However, it only showed a minor inhibition on the activity of Aurora kinase and histone deacetylase. Mana-Hox induced mitotic arrest of the cell cycle identified by downregulation of cyclin E, cyclin A, and cyclin-dependent kinase 2 (Cdk2) and an increase of MPM-2 expression. Next, it caused Bcl-2 phosphorylation on Ser-70, downregulation of Mcl-1 expression, and activation of caspase-3, leading to apoptotic cell death. Notably, Mana-Hox was not a P-glycoprotein (P-gp) substrate and showed equipotent activity against P-gp-rich cancer cells. We conclude that Mana-Hox induces dual effects on DNA damage and tubulin depolymerization, leading to mitotic arrest and activation of mitochondria-mediated apoptotic pathways. Data provide evidence that the anticancer strategy of dual-action targets could be a potential anticancer approach.
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Liu D, Wei Y, Zhou F, Ge Y, Xu J, Chen H, Zhang W, Yun X, Jiang J. E1AF promotes mithramycin A-induced Huh-7 cell apoptosis depending on its DNA-binding domain. Arch Biochem Biophys 2008; 477:20-6. [PMID: 18510939 DOI: 10.1016/j.abb.2008.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 04/11/2008] [Accepted: 05/07/2008] [Indexed: 11/28/2022]
Abstract
Transcription factor E1AF is widely known to play critical roles in tumor metastasis via directly binding to the promoters of genes involved in tumor migration and invasion. Here, we reported for the first time the pro-apoptotic role of E1AF in tumor cells. The expression of E1AF at protein level was obviously increased during Huh-7 and Hep3B cells apoptosis induced by the anticancer agent mithramycin A. E1AF overexpression markedly enhanced mithramycin A-induced Huh-7 cell apoptosis and the expression of pro-apoptotic protein Bax depending on its DNA-binding domain. And, reduction of E1AF inhibited mithramycin A-induced Huh-7 cell apoptosis. Furthermore, reducing the expression of Bax significantly inhibited E1AF-increased Huh-7 cell apoptosis induced by mithramycin A. Taken together, E1AF increases mithramycin A-induced Huh-7 cells apoptosis and Bax expression depending on its DNA-binding domain, indicating that E1AF might contribute to the therapeutic efficiency of mithramycin A for hepatoma.
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Affiliation(s)
- Dan Liu
- Key Laboratory of Glycoconjugates Research, Ministry of Public Health & Gene Research Center, Shanghai Medical College of Fudan University, Dongan Road 130, Shanghai 200032, People's Republic of China
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Han JC, Zhang KL, Chen XY, Jiang HF, Kong QY, Sun Y, Wu ML, Huang L, Li H, Liu J. Expression of seven gastric cancer-associated genes and its relevance for Wnt, NF-kappaB and Stat3 signaling. APMIS 2008; 115:1331-43. [PMID: 18184402 DOI: 10.1111/j.1600-0643.2007.00695.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The aim of the current study was to profile c-Myc, standard CD44 (CD44s), CD44v6, cyclin D1, survivin, MMP-7 and VEGF expression patterns in different gastric samples and to elucidate their relevance for Wnt, NF-kappaB and/or Stat3 activation using multiple experimental approaches. The results revealed that 87.1% (27/31) of gastric cancers and 8.7% (2/23) of noncancerous lesions (chronic gastritis and intestinal metaplasia) showed Wnt activation (Wnt(+)) that was closely related to the expression of the seven genes. Some Wnt(-) noncancerous lesions also expressed the above-mentioned genes, higher frequencies of survivin (7/8), VEGF (7/8), cyclin D1 (6/8) and c-Myc (5/8) but not CD44s (2/8), CD44v6 (3/8) and MMP-7 (2/8) being detected in the NF-kappaB(+) samples. Stat3 was activated in 37/54 gastric tissues, and in 3/4 VEGF, 4/6 c-Myc, 4/8 survivin, 2/4 MMP-7, 1/2 CD44v6, and 4/9 cyclin D1(+) but Wnt(-)/NF-kappaB(-) samples. These findings showed a close correlation in GCs between Wnt, NF-kappaB and Stat3 signaling and expression of the seven genes, the importance of NF-kappaB and Stat3 activation in regulating c-Myc, survivin, cyclin D1 and VEGF in noncancerous lesions, and the potential coordinative effects of these three signalings on GC formation presumably by promoting the transcription of their common target genes.
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Affiliation(s)
- Jing-Chun Han
- Liaoning Laboratory of Cancer Genomics and Department of Cell Biology, College of Basic Medical Sciences, Dalian Medical University, P. R. China
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Jin Y, Wei Y, Xiong L, Yang Y, Wu JR. Differential regulation of survivin by p53 contributes to cell cycle dependent apoptosis. Cell Res 2007; 15:361-70. [PMID: 15916722 DOI: 10.1038/sj.cr.7290303] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Recent studies indicate that cell-cycle checkpoints are tightly correlated with the regulation of apoptosis, in which p53 plays an important role. Our present works show that the expression of E6/E7 oncogenes of human papillomavirus in HeLa cells is inhibited in the presence of anti-tumor reagent tripchlorolide (TC), which results in the up-regulation of p53 in HeLa cells. Interestingly, under the same TC-treatment, the cells at the early S-phase are more susceptible to apoptosis than those at the middle S-phase although p53 protein is stabilized to the same level in both situations. Significant difference is exhibited between the two specified expression profiles. Further analysis demonstrates that anti-apoptotic gene survivin is up-regulated by p53 in the TC-treated middle-S cells, whereas it is down-regulated by p53 in the TC-treated early-S cells. Taken together, the present study indicates that the differential p53-regulated expression of survivin at different stages of the cell cycle results in different cellular outputs under the same apoptosis-inducer.
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Affiliation(s)
- Yan Jin
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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33
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Song G, Liao X, Zhou L, Wu L, Feng Y, Han ZC. HI44a, an anti-CD44 monoclonal antibody, induces differentiation and apoptosis of human acute myeloid leukemia cells. Leuk Res 2007; 28:1089-96. [PMID: 15289023 DOI: 10.1016/j.leukres.2004.02.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2003] [Accepted: 02/27/2004] [Indexed: 12/15/2022]
Abstract
CD44 is a cell surface antigen that expresses on leukemia blasts from most acute myeloid leukemia (AML) patients. It has been reported that ligation of CD44 with some specific anti-CD44 monoclonal antibodies can reverse the differentiation blockage of leukemia cell lines. In this study, the differentiation and apoptosis-inducing effects of HI44a, another anti-CD44 monoclonal antibody (IgG2a), were investigated on leukemia cells obtained from 31 patients with AML-M2, AML-M3, AML-M4 or AML-M5. When the AML cells were treated with HI44a, the percentage of nitroblue tetrazolium (NBT)+ cells was significantly increased. The expression of CD11b, CD14 and CD15 on treated AML cells was also increased compared to control AML cells. In addition, HI44a was found to induce apoptosis of leukemia cells, as evidenced by an annexin-V assay. The mean percentage of apoptotic cells in HI44a-treated AML cells was significantly increased compared to that in control AML cells. Moreover, the level of c-myc transcript expression on AML cells was found to be obviously decreased in all detected patients. These results indicate that HI44a effectively induces both differentiation and apoptosis of AML cells and suggest that this activity of the anti-CD44 antibody may be associated with its inhibitory effect on c-myc transcript expression.
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Affiliation(s)
- Guoli Song
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Hospital of Blood Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China
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Goga A, Yang D, Tward AD, Morgan DO, Bishop JM. Inhibition of CDK1 as a potential therapy for tumors over-expressing MYC. Nat Med 2007; 13:820-7. [PMID: 17589519 DOI: 10.1038/nm1606] [Citation(s) in RCA: 254] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Accepted: 05/16/2007] [Indexed: 01/18/2023]
Abstract
Tumor cells have a dysregulated cell cycle that may render their proliferation especially sensitive to the inhibition of cyclin-dependent kinases (CDKs), important regulators of cell cycle progression. We examined the effects of CDK1 inhibition in the context of different oncogenic signals. Cells transformed with MYC, but not cells transformed by a panel of other activated oncogenes, rapidly underwent apoptosis when treated with small-molecule CDK1 inhibitors. The inhibitor of apoptosis protein BIRC5 (survivin), a known CDK1 target, is required for the survival of cells overexpressing MYC. Inhibition of CDK1 rapidly downregulates survivin expression and induces MYC-dependent apoptosis. CDK1 inhibitor treatment of MYC-dependent mouse lymphoma and hepatoblastoma tumors decreased tumor growth and prolonged their survival. As there are no effective small-molecule inhibitors that selectively target the MYC pathway, we propose that CDK1 inhibition might therefore be useful in the treatment of human malignancies that overexpress MYC.
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Affiliation(s)
- Andrei Goga
- Department of Medicine, Division of Hematology/Oncology, University of California, San Francisco, San Francisco, California 94143-0552, USA.
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35
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Naruse T, Nishida Y, Ishiguro N. Synergistic effects of meloxicam and conventional cytotoxic drugs in human MG-63 osteosarcoma cells. Biomed Pharmacother 2007; 61:338-46. [PMID: 17395421 DOI: 10.1016/j.biopha.2007.02.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Accepted: 02/12/2007] [Indexed: 11/20/2022] Open
Abstract
Cyclooxygenase-2 (COX-2) inhibitors have been shown to exert inhibitory effects on many types of malignant tumors and several groups have suggested that COX-2 inhibitors enhance the cytotoxic effects of other anti-cancer agents. We previously reported that meloxicam has an anti-tumorigenic effect on COX-2-expressing osteosarcoma cells. In the current study, we evaluated the synergy between meloxicam and cisplatin (CDDP), doxorubicin (DXR) and 4-hydroperoxy ifosfamide (4OOH-IFM), using the human osteosarcoma cell line, MG-63. Cytotoxicity was determined using 3-(4,5'-dimethylthiazol-2-yl)-2,5'-diphenyltetrazolium bromide (MTT) assays, and isobolographic analysis was used to evaluate any synergy. Apoptotic activity was determined by terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL), and by evaluating Bax and Bcl-2 expression levels using real-time RT-PCR and western blotting analysis. Cell cycling was evaluated by flow cytometry. The cytotoxic effects of CDDP and DXR were enhanced synergistically in the presence of meloxicam and were partially due to an increase in apoptosis. By contrast, meloxicam enhanced neither the cytotoxic nor the apoptotic activity of 4OOH-IFM. Combining meloxicam with DXR significantly up-regulated Bax expression, whereas it down-regulated Bcl-2 expression in combination with CDDP. Furthermore, the number of cells in the G2/M phase was significantly increased in DXR-treated samples by the addition of meloxicam, but not in CDDP-treated or 4OOH-IFM-treated samples. These results suggest a potential clinical application of meloxicam in combination with cytotoxic drugs in patients with COX-2-positive osteosarcoma.
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Affiliation(s)
- T Naruse
- Department of Orthopaedic Surgery, Nagoya University School and Graduate School of Medicine, 65-Tsurumai, Showa, Nagoya, 466-8550, Japan.
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36
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Yang D, Hurley LH. Structure of the biologically relevant G-quadruplex in the c-MYC promoter. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2006; 25:951-68. [PMID: 16901825 DOI: 10.1080/15257770600809913] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The nuclease hypersensitivity element III1 (NHE III1) in the c-MYC promoter controls up to 80-90% of the transcriptional activity of this gene. We have demonstrated that the guanine-rich strand of the NHE III1 forms a G-quadruplex consisting of a mixture of four biologically relevant loop isomers that function as a silencer element. NMR studies have shown that these G-quadruplexes are propeller-type parallel structures consisting of three stacked G-tetrads and three double-chain reversal loops. An NMR-derived solution structure for this quadruplex provides insight into the unusual stability of the structure. This structure is a target for small molecule inhibitors of c-MYC gene expression.
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Affiliation(s)
- Danzhou Yang
- University of Arizona, College of Pharmacy, Tucson, AZ 85721, USA
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Abstract
Myc expression is deregulated in a wide range of human cancers and is often associated with aggressive, poorly differentiated tumors. The Myc protein is a transcription factor that regulates a variety of cellular processes including cell growth and proliferation, cell-cycle progression, transcription, differentiation, apoptosis, and cell motility. Potential strategies that either inhibit the growth promoting effect of Myc and/or activate its pro-apoptotic function are presently being explored. In this review, we give an overview of Myc activation in human tumors and discuss current strategies aimed at targeting Myc for cancer treatment. Such therapies could have potential in combination with mechanistically different cytotoxic drugs to combat and eradicate tumors cells.
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Affiliation(s)
- Marina Vita
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
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Hong J, Zhao Y, Huang W. Blocking c-myc and stat3 by E. coli expressed and enzyme digested siRNA in mouse melanoma. Biochem Biophys Res Commun 2006; 348:600-5. [PMID: 16890193 DOI: 10.1016/j.bbrc.2006.07.107] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Accepted: 07/19/2006] [Indexed: 12/26/2022]
Abstract
Tumour cells often show alteration in the signal-transduction pathways, leading to proliferation in response to external signals. Oncogene overexpression and constitutive expression is a common phenomenon in the development and progression of many human cancers. Therefore oncogenes provide potential targets for cancer therapy. RNA interference (RNAi), mediated by small interfering RNA (siRNA), silences genes with a high degree of specificity and potentially represents a general approach for molecularly targeted anti-cancer therapy. The data presented in this report evaluated the method of systemically administering combined esiRNAs to multiple targets as compared with the method of using a single kind of esiRNA to a single target. Our experimental data revealed that the mixed treatment of esiC-MYC and esiSTAT3 had a better inhibition effect than the single treatment of esiC-MYC or esiSTAT3 on mouse B16 melanoma.
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Affiliation(s)
- Jie Hong
- Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433, China
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Borgne A, Versteege I, Mahé M, Studeny A, Léonce S, Naime I, Rodriguez M, Hickman JA, Meijer L, Golsteyn RM. Analysis of cyclin B1 and CDK activity during apoptosis induced by camptothecin treatment. Oncogene 2006; 25:7361-72. [PMID: 16785996 DOI: 10.1038/sj.onc.1209718] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have studied the role of cyclins and cyclin-dependent kinase (CDK) activity in apoptosis induced by camptothecin (CPT). In this model, 22% of the cells stain for annexin-V at 24 h and then proceed to be 93% positive by 72 h. This time window permits the analysis of cyclins in cells that are committed to apoptosis but not yet dead. We provide evidence that cyclin protein levels and then associated kinase levels increase after CPT treatment. Strikingly, cyclin B1 and cyclin E1 proteins are present at the same time in CPT treated HT29 cells. Although cyclin B1 and E1 CDK complexes are activated in CPT treated cells, only the cyclin B1 complex is required for apoptosis since reduction of cyclin B1 by RNAi or roscovitine treatment reduces the number of annexin-V-stained cells. We have detected poorly organized chromosomes and phosphorylated histone H3 epitopes at the time of maximum cyclin B1/CDK kinase activity in CPT-treated cells, which suggests that these cells enter a mitotic catastrophe. Understanding which CDKs are required for apoptosis may allow us to better adapt CDK inhibitors for use as anti-cancer compounds.
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Affiliation(s)
- A Borgne
- Institut de Recherches Servier, Cancer Drug Discovery, Croissy-sur-Seine, France
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Pirity M, Blanck JK, Schreiber-Agus N. Lessons learned from Myc/Max/Mad knockout mice. Curr Top Microbiol Immunol 2006; 302:205-34. [PMID: 16620030 DOI: 10.1007/3-540-32952-8_8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The past two decades of gene targeting experiments have allowed us to make significant strides towards understanding how the Myc/Max/Mad network influences multiple aspects of cellular behavior during development. Here we summarize the findings obtained from the myc/max/mad knockout mice generated to date, namely those in which the N-myc, c-myc, L-myc, mad1, mxi1, mad3, mnt, or max genes have been targeted. A compilation of lessons we have learned from these myc/max/mad knockout mouse models, and suggestions as to where future efforts could be focused, are also presented.
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Affiliation(s)
- M Pirity
- Department of Molecular Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Ullmann 809, Bronx, NY 10461, USA
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Zhang P, Li H, Wu ML, Chen XY, Kong QY, Wang XW, Sun Y, Wen S, Liu J. c-Myc downregulation: a critical molecular event in resveratrol-induced cell cycle arrest and apoptosis of human medulloblastoma cells. J Neurooncol 2006; 80:123-31. [PMID: 16724266 DOI: 10.1007/s11060-006-9172-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Accepted: 04/03/2006] [Indexed: 12/24/2022]
Abstract
The correlation of c-Myc expression with resveratrol-induced turnover of medulloblastoma cells was investigated in this study by checking (1) c-Myc expression in medulloblastoma tissues and cell lines (UW228-2 and UW228-3), (2) the in vitro effect of resveratrol on c-Myc expression and (3) the influences of c-Myc inhibition in cell growth and survival. Immunohistochemical staining of human medulloblastomas and noncancerous cerebellar tissues revealed that 8 out of 11 tumor tissues (72.7%) expressed c-Myc, in which 4 cases (50%) showed intensified nuclear labeling. RT-PCR, Western blotting, immunocytochemical and immunofluorescence stainings revealed c-Myc downregulation accompanied with growth suppression and apoptosis. Flow cytometry analysis showed S phase arrest in resveratrol-treated cell populations. Transfection of c-Myc directed antisense oligonucleotides to the cultured medulloblastoma cells could reduce c-Myc expression, inhibit cell growth and arrest the cell cycle at S phase. Our results thus for the first time demonstrate that c-Myc downregulation is a critical molecular event of resveratrol-mediated anti-medulloblastoma activity, which is closely associated with growth suppression, cell cycle arrest and apoptosis of medulloblastoma cells.
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Affiliation(s)
- Peng Zhang
- Cancer Institute and Liaoning Laboratory of Cancer Genomics, College of Basic Medical Sciences, Dalian Medical University, 116027, Dalian, P. R. China
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Albihn A, Lovén J, Ohlsson J, Osorio LM, Henriksson M. c-Myc-dependent etoposide-induced apoptosis involves activation of Bax and caspases, and PKCdelta signaling. J Cell Biochem 2006; 98:1597-614. [PMID: 16572399 DOI: 10.1002/jcb.20816] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The c-Myc transcription factor is a key regulator of cell proliferation, differentiation, and apoptosis. While deregulation of myc induces programmed cell death, defects in the apoptotic program facilitate Myc-driven tumor development. We have treated c-Myc inducible mouse cells and rat fibroblasts with different c-myc status with cytotoxic drugs to explore the effect of c-Myc on drug-induced apoptosis. We found that c-Myc overexpression potentiated etoposide-, doxorubicin-, and cisplatin-induced cell death in mouse fibroblasts. In addition, these drugs provoked a strong apoptotic response in c-Myc-expressing cells, but a weak apoptosis in c-myc null Rat1 cells. In contrast, staurosporine-induced apoptosis was c-Myc-independent, confirming a functional apoptotic pathway in c-myc null cells. Apoptosis was paralleled by c-Myc-dependent Bax-activation after etoposide and doxorubicin treatment, but not after cisplatin administration. All three drugs induced higher caspase activation in c-Myc expressing cells than in c-myc null cells. Furthermore, etoposide treatment of c-Myc expressing cells resulted in PKCdelta cleavage, while inhibition of PKCdelta reduced etoposide-induced apoptosis and prevented Bax activation. Taken together, these findings suggest that Bax and caspase activation, together with PKCdelta signaling are involved in c-Myc-dependent etoposide-induced apoptosis.
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Affiliation(s)
- Ami Albihn
- Microbiology and Tumor Biology Center, Karolinska Institutet, S-171 77 Stockholm, Sweden
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Wei Y, Jiang J, Sun M, Chen X, Wang H, Gu J. ATF5 increases cisplatin-induced apoptosis through up-regulation of cyclin D3 transcription in HeLa cells. Biochem Biophys Res Commun 2005; 339:591-6. [PMID: 16300731 DOI: 10.1016/j.bbrc.2005.11.054] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Accepted: 11/10/2005] [Indexed: 10/25/2022]
Abstract
ATF5 transcription factor plays an essential role in hematopoietic and glioma cell survival and neuronal cell differentiation. Here, we report for the first time the pro-apoptosis role of ATF5 and identify Cyclin D3 as an ATF5-targeted apoptosis-related gene. The ectopic expression of ATF5 in HeLa cells could markedly increase cisplatin-induced apoptosis and the cleavage of Caspase-3, and induce Cyclin D3 mRNA expression via cooperation with E2F1 transcription factor. Moreover, the interference of Cyclin D3 expression by transfection with Cyclin D3 RNAi could protect cells from ATF5-mediated apoptosis induced by cisplatin, indicating the contribution of Cyclin D3 in ATF5-mediated apoptosis. Taken together, these results suggest that ATF5 increases cisplatin-induced apoptosis through up-regulation of Cyclin D3 transcription, which elicits survival signals in HeLa cells.
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Affiliation(s)
- Yuanyan Wei
- State Key Laboratory of Genetic Engineering and Gene Research Center, Shanghai Medical College of Fudan University, Shanghai 200032, People's Republic of China
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Ponzielli R, Katz S, Barsyte-Lovejoy D, Penn LZ. Cancer therapeutics: targeting the dark side of Myc. Eur J Cancer 2005; 41:2485-501. [PMID: 16243519 DOI: 10.1016/j.ejca.2005.08.017] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The potent Myc oncoprotein plays a pivotal role as a regulator of tumorigenesis in numerous human cancers of diverse origin. Experimental evidence shows that inhibiting Myc significantly halts tumour cell growth and proliferation. This review summarises recent progress in understanding the function of Myc as a transcription factor, with emphasis on key protein interactions and target gene regulation. In addition, major advances in drug development aimed at eliminating Myc are described, including antisense and triple helix forming oligonucleotides, porphyrins and siRNA. Future anti-Myc strategies are also discussed that inhibit Myc at the level of expression and/or function. Targeting the dark side of Myc with novel therapeutic agents promises to have a profound impact in combating cancer.
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Affiliation(s)
- Romina Ponzielli
- Ontario Cancer Institute/Princess Margaret Hospital, Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, Ont., Canada M5G 2M9
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Maire MA, Rast C, Vasseur P. Di-(2-ethylhexyl)phthalate (DEHP) increases Bcl-2/Bax ratio and modifies c-myc expression in Syrian hamster embryo (SHE) cells. Toxicol Lett 2005; 158:237-45. [PMID: 15923092 DOI: 10.1016/j.toxlet.2005.04.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Revised: 04/04/2005] [Accepted: 04/05/2005] [Indexed: 11/18/2022]
Abstract
The objective of this work was to study the anti-apoptotic properties of the non-genotoxic rodent carcinogen, di(2-ethylhexyl)phthalate (DEHP) in Syrian hamster embryo (SHE) cells. We demonstrated that a 24 h pre-treatment of SHE cells with 50 microM DEHP inhibited apoptosis triggered by growth factors deprivation. The RNA expression levels of the regulator genes involved in the apoptotic pathway, bcl-2, bax and of c-myc were measured using Western blotting and RT-PCR. We showed that a 24 h treatment of SHE cells with 50 microM DEHP increased (P < 0.05) the bcl-2 expression, while c-myc expression was decreased. No effect on bax expression was observed in the range of 10-50 microM. The defective regulation of apoptosis caused by DEHP treatment could contribute to its carcinogenicity.
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Affiliation(s)
- M A Maire
- ESE, Université de Metz, Faculté des Sciences, Campus Bridoux, rue du Général Delestraint, 57070 Metz, France.
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Bucci B, D'Agnano I, Amendola D, Citti A, Raza GH, Miceli R, De Paula U, Marchese R, Albini S, Felsani A, Brunetti E, Vecchione A. Myc down-regulation sensitizes melanoma cells to radiotherapy by inhibiting MLH1 and MSH2 mismatch repair proteins. Clin Cancer Res 2005; 11:2756-67. [PMID: 15814658 DOI: 10.1158/1078-0432.ccr-04-1582] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Melanoma patients have a very poor prognosis with a response rate of <1% due to advanced diagnosis. This type of tumor is particularly resistant to conventional chemotherapy and radiotherapy, and the surgery remains the principal treatment for patients with localized melanoma. For this reason, there is particular interest in the melanoma biological therapy. EXPERIMENTAL DESIGN Using two p53 mutant melanoma models stably expressing an inducible c-myc antisense RNA, we have investigated whether Myc protein down-regulation could render melanoma cells more susceptible to radiotherapy, reestablishing apoptotic p53-independent pathway. In addition to address the role of p53 in the activation of apoptosis, we studied the effect of Myc down-regulation on radiotherapy sensitivity also in a p53 wild-type melanoma cell line. RESULTS Myc down-regulation is able per se to induce apoptosis in a fraction of the cell population (approximately 40% at 72 hours) and in combination with gamma radiation efficiently enhances the death process. In fact, approximately 80% of apoptotic cells are evident in Myc down-regulated cells exposed to gamma radiation for 72 hours compared with approximately 13% observed after only gamma radiation treatment. Consistent with the enhanced apoptosis is the inhibition of the MLH1 and MSH2 mismatch repair proteins, which, preventing the correction of ionizing radiation mismatches occurring during DNA replication, renders the cells more prone to radiation-induced apoptosis. CONCLUSIONS Data herein reported show that Myc down-regulation lowers the apoptotic threshold in melanoma cells by inhibiting MLH1 and MSH2 proteins, thus increasing cell sensitivity to gamma radiation in a p53-independent fashion. Our results indicate the basis for developing new antitumoral therapeutic strategy, improving the management of melanoma patients.
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Affiliation(s)
- Barbara Bucci
- Associazione Fatebenefratelli per la Ricerca-Centro Ricerca S. Pietro and Unita di Radioterapia Oncologica S. Pietro, Fatebenefratelli Hospital, Rome, Italy.
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Halder K, Chowdhury S. Kinetic resolution of bimolecular hybridization versus intramolecular folding in nucleic acids by surface plasmon resonance: application to G-quadruplex/duplex competition in human c-myc promoter. Nucleic Acids Res 2005; 33:4466-74. [PMID: 16085756 PMCID: PMC1183106 DOI: 10.1093/nar/gki750] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The human oncogene c-myc is regulated by G-quadruplex formation within the nuclease hypersensitive element (NHE IIII) in the c-myc promoter, making the quadruplex a strong anti-cancer target. With respect to this, the competing equilibrium between intramolecular quadruplex folding and bimolecular duplex formation is poorly understood and very few techniques have addressed this problem. We present a method for simultaneously determining the kinetic constants for G-quadruplex folding/unfolding and hybridization in the presence of the complementary strand from a single reaction using an optical biosensor based on surface plasmon resonance (SPR). Using this technique, we demonstrate for the first time that quadruplex formation in the c-myc promoter is favored at low strand concentrations. Our results indicate favorable quadruplex folding (equilibrium folding constant KF of 2.09 calculated from the kinetic parameters: folding rate constant, kf = 1.65 × 10−2 s−1 and unfolding rate constant, ku = 7.90 × 10−3 s−1) in 150 mM K+. The hybridization rate constants detected concurrently gave a bimolecular association constant, ka = 1.37 × 105 M−1 s−1 and dissociation constant, kd = 4.94 × 10−5 s−1. Interestingly, in the presence of Na+ we observed that G-quadruplex folding was unfavorable (KF = 0.54). Implication of our results on the c-myc transcription activation model is discussed in light of aberrant c-myc expression observed on destabilization of the G-quadruplex.
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Affiliation(s)
| | - Shantanu Chowdhury
- To whom correspondence should be addressed. Tel: +91 11 2766 6157; Fax: +91 11 2766 7471;
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Golsteyn RM. Cdk1 and Cdk2 complexes (cyclin dependent kinases) in apoptosis: a role beyond the cell cycle. Cancer Lett 2005; 217:129-38. [PMID: 15617830 DOI: 10.1016/j.canlet.2004.08.005] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Accepted: 08/04/2004] [Indexed: 11/22/2022]
Abstract
The family of cyclin-dependent kinase complexes (Cdks) are well known for their role in the cell division cycle. What is less well known, however, is that Cdks also participate in a subset of apoptosis programs. Evidence for the role of Cdks in apoptosis comes from a variety of experimental approaches, including studies using genetic mutants, protein inhibitors, and chemical inhibitors of protein kinase activity. The precise role of Cdks in apoptosis remains to be defined, although one promising approach to clarify this question is to identify Cdk protein substrates during apoptosis. Currently a number of Cdk inhibitors are being tested in clinical trials. By understanding how Cdks function during apoptosis it may be possible to optimise the use of these inhibitors in treating human tumours by blocking proliferation but permitting apoptosis.
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Affiliation(s)
- Roy M Golsteyn
- Cancer Research Division, Institut de Recherches Servier, 125 ch. de Ronde, Croissy-sur-Seine, Paris F 78290, France.
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Fu XB, Li XK, Wang T, Cheng B, Sheng ZY. Enhanced anti-apoptosis and gut epithelium protection function of acidic fibroblast growth factor after cancelling of its mitogenic activity. World J Gastroenterol 2004; 10:3590-6. [PMID: 15534912 PMCID: PMC4611998 DOI: 10.3748/wjg.v10.i24.3590] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM: Mitogenic and non-mitogenic activities of fibroblast growth factor (FGF) are coupled to a range of biological functions, from cell proliferation and differentiation to the onset of many diseases. Recent reports have shown that acidic fibroblast growth factor (aFGF) has a powerful anti-apoptosis function, which may have potentially therapeutical effect on gut ischemia and reperfusion injuries. However, whether this function depends on its mitogenic or non-mitogenic activity remains unclear. In this study, we identified the source of its anti-apoptosis function with a mutant, aFGF28-154 and observed its effect on reducing gut ischemia and reperfusion injury.
METHODS: aFGF28-154 was generated by amplification of appropriate DNA fragments followed by subcloning the products into pET-3c vectors, then they were expressed in BL21 (DE3) cells and purified on an M2 agarose affinity column. This mutant aFGF28-154 maintained its non-mitogenic activity and lost its mitogenic activity. With a dexamethasone (DEX)-induced mouse thymocyte apoptosis model in vitro and in vivo, we studied the anti-apoptotic function of aFGF28-154. Also, in vivo study was performed to further confirm whether aFGF28-154 could significantly reduce apoptosis in gut epithelium after gut ischemia-reperfusion injury in rats. Based on these studies, the possible signal transduction pathways involved were studied.
RESULTS: With a dexamethasone (DEX)-induced mouse thymocyte apoptosis model in vitro and in vivo, we found that the anti-apoptotic function of aFGF28-154 was significantly enhanced when compared with the wild type aFGF. In vivo study further confirmed that aFGF28-154 significantly reduced apoptosis in gut epithelium after gut ischemia-reperfusion injury in rats. The mechanisms of anti-apoptosis function of aFGF28-154 did not depend on its mitogenic activity and were mainly associated with its non-mitogenic activities, including the intracellular calcium ion balance protection, ERK1/2 activation sustaining and cell cycle balance.
CONCLUSION: These findings emphasize the importance of non-mitogenic effects of aFGF, and have implications for its therapeutic use in preventing apoptosis and other injuries in tissues and internal organs triggered by ischemia-reperfusion injury.
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Affiliation(s)
- Xiao-Bing Fu
- Wound Healing and Cell Biology Laboratory, Burns Institute, 304 Medical Department, General Hospital of PLA, Trauma Centre of Postgraduate Medical College, 51 Fucheng Road, Beijing 100037, China.
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Maeda S, Sugiura T, Saikawa Y, Kubota T, Otani Y, Kumai K, Kitajima M. Docetaxel enhances the cytotoxicity of cisplatin to gastric cancer cells by modification of intracellular platinum metabolism. Cancer Sci 2004; 95:679-84. [PMID: 15298732 PMCID: PMC11158986 DOI: 10.1111/j.1349-7006.2004.tb03329.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
We have examined the combined anticancer effects of docetaxel (DOC) and cisplatin (CDDP) in vitro using the gastric cancer cell lines MKN-45, MKN-74, and TMK-1. Treatment of the cell lines with 30 microg/ml of DOC for 24 h followed by incubation with 3 or 10 microg/ml of CDDP for 24 h showed a clear synergistic effect. Sequence dependency of the agents was observed in these cell lines: DOC followed by CDDP (DC) showed a stronger antitumor effect than CDDP followed by DOC (CD) in all cell lines. To clarify the mechanism of action of the DC combination, total intracellular platinum (Pt) levels were evaluated after treatment with CDDP alone or combined with DC. For the MKN-45 and -74 cell lines, cells treated with DOC (10 microg/ml for 12 h) and then CDDP showed significantly increased intracellular Pt accumulation compared to cells treated with CDDP alone. We also investigated alterations in intracellular glutathione (GSH) concentration in response to DOC and CDDP. MKN-45 and -74 cells pretreated with DOC (10 microg/ml for 12 h) showed significantly increased intracellular GSH levels compared to cells administered CDDP only. To explain these findings, messenger RNA (mRNA) levels for multidrug resistance-associated protein-1 (MRP-1), the ATP-dependent pump for Pt-GSH complexes, were quantified in CDDP-treated MKN-45 cells with and without DOC pretreatment. While CDDP administration increased MRP-1 mRNA expression in MKN-45 cells, MRP-1 was not up-regulated after CDDP administration in DOC pretreated MKN-45 cells. Our results suggested that the enhanced CDDP toxicity due to DOC pretreatment may be related to the accumulation of intracellular Pt-GSH complexes, because DOC appears to suppress the MRP-1 up-regulation induced by CDDP exposure in gastric cancer cells.
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Affiliation(s)
- Shingo Maeda
- Department of Surgery, School of Medicine, Keio University, Shinjuku-ku, Tokyo 160-8582, Japan
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