• Inhibitor
• UBC13
• Ubiquitination

• Humans
• Ubiquitin-Conjugating Enzymes/metabolism
• Ubiquitin-Conjugating Enzymes/antagonists & inhibitors
• Ubiquitin-Conjugating Enzymes/chemistry
• Neoplasms/metabolism
• Neoplasms/drug therapy
• Neoplasms/pathology
• Ubiquitination
• Animals
• Enzyme Inhibitors/chemistry
• Enzyme Inhibitors/pharmacology
• Molecular Structure
• Inflammation/metabolism
• Inflammation/drug therapy

• Tumor Suppressor Protein p53/chemistry
• Tumor Suppressor Protein p53/metabolism
• Molecular Dynamics Simulation
• Allosteric Regulation
• Humans

• R15 GM128102 NIGMS NIH HHS
• National Science Foundation
• National Institute of General Medical Sciences

• DNA damage response
• Diagnosis
• Hematological malignancies
• P53
• P53 Regulation
• Prognosis
• Therapy
• Tumor suppressor

• AML immunotherapies
• TP53 mutations
• TP53-mutated acute myeloid leukemia
• acute myeloid leukemia
• novel targeted AML therapies

• HBsAg
• ROS
• hepatitis B virus
• rtA181T mutation
• rtA181V mutation

• Humans
• Hepatitis B virus/genetics
• Carcinoma, Hepatocellular/genetics
• Carcinoma, Hepatocellular/drug therapy
• Hepatitis B, Chronic/drug therapy
• Antiviral Agents/therapeutic use
• Mutation Rate
• Liver Neoplasms/genetics
• Liver Neoplasms/drug therapy
• Mutation
• Genes, Tumor Suppressor
• DNA, Viral/genetics
• Hepatitis B Surface Antigens/genetics

• Capital Health Research and Development Special grants
• Chinesisch-Deutsches Forschungsprojekt im Sonderprogramm zu COVID-19 (C-0012) and Key Programs of Beijing Municipal Education Commission of China
• National Key Research and Development Program of China
• Third Round of Public Welfare Development and Reform Pilot Projects of Beijing Municipal Medical Research Institutes

• Atomic force microscopy
• G-quadruplex
• Supercoiled DNA
• p53 isoforms
• p53-DNA binding

• Forkhead Box Protein L2/metabolism
• Forkhead Transcription Factors/metabolism
• Hepatocyte Nuclear Factor 3-alpha/metabolism
• Humans
• Promoter Regions, Genetic
• Tumor Suppressor Protein p53/genetics
• Tumor Suppressor Protein p53/metabolism

• Korean government

Background: The relationship of TP53 codons 72, IVS3 16 bp, and IVS6+62A > G polymorphisms with breast cancer (BC) risk has been analyzed in seventeen published meta-analyses. However, the credibility of statistically significant associations was ignored and many new studies have been reported on these themes.

Objectives: To explore whether TP53 codons 72, IVS3 16 bp, and IVS6+62A > G polymorphisms are associated with BC risk and the clinical phenomena.

Methods: To comprehensively search the data (through October 25, 2021), we provided a clear search strategy and reviewed the references of published meta-analyses. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were used.

Results: The current meta-analysis had a larger sample size than the previous ones: 99 studies with 43,951 BC and 48,479 controls for TP53 codon 72 polymorphism, 35 studies with 8,705 BC and 7,516 controls for IVS3 16 bp polymorphism, and 25 studies with 12,222 BC and 12,895 controls for IVS6+62A > G polymorphism. Five gene models were used to explore the association between the three polymorphisms and BC risk, and partial positive results were similar to published meta-analyses results. However, a large number of significant results were considered to be unreliable after correcting with Bayesian false-discovery probability (BFDP), except for the association between TP53 IVS3 16 bp polymorphism and BC risk in overall analysis (GG vs. CC: BFDP = 0.738), matched studies (GG vs. CC: BFDP = 0.173; GG vs. CC + CG: BFDP = 0.447), and tumor size below 2 cm (GG vs. CC: BFDP = 0.088; GG + CG vs. CC: BFDP = 0.730; GG vs. CC + CG: BFDP = 0.311). These unreliable results were confirmed again without new solid results emerging in further sensitivity analysis (only studies in compliance with the quality assessment standard).

Conclusion: After considering the quality of the included studies and the reliability of the results, the present meta-analysis suggested that TP53 codons 72, IVS3 16 bp, and IVS6+62A > G polymorphisms were not significantly associated with the BC risk. Those results which prove that these three polymorphisms increase BC risk are more likely to be false-positive results due to various confounding factors.

Background: Management of patients with prostate cancer and bone metastatic disease remains a major clinical challenge. Loss or mutation of p53 has been identified to be involved in the tumor progression and metastasis. Nevertheless, direct evidence of a specific role for wild-type p53 (wt-p53) in bone metastasis and the mechanism by which this function is mediated in prostate cancer remain obscure.

Methods: The expression and protein levels of wt-53, AIP4, and CXCR4 in prostate cancer cells and clinical specimens were assessed by real-time PCR, immunohistochemistry and western blot analysis. The role of wt-p53 in suppressing aggressive and metastatic tumor phenotypes was assessed using in vitro transwell chemotaxis, wound healing, and competitive colocalization assays. Furthermore, whether p53 deletion facilitates prostate cancer bone-metastatic capacity was explored using an in vivo bone-metastatic model. The mechanistic model of wt-p53 in regulating gene expression was further explored by a luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay.

Results: Our findings revealed that wt-p53 suppressed the prostate cancer cell migration rate, chemotaxis and attachment toward the osteoblasts in vitro. The bone-metastatic model showed that deletion of wt-p53 remarkably increased prostate cancer bone-metastatic capacity in vivo. Mechanistically, wt-p53 could induce the ligand-induced degradation of the chemokine receptor CXCR4 by transcriptionally upregulating the expression of ubiquitin ligase AIP4. Treatment with the CXCR4 inhibitor AMD3100 or transduction of the AIP4 plasmid abrogated the pro-bone metastasis effects of TP53 deletion.

Conclusion: Wt-p53 suppresses the metastasis of prostate cancer cells to bones by regulating the CXCR4/CXCL12 activity in the tumor cells/bone marrow microenvironment interactions. Our findings suggest that targeting the wt-p53/AIP4/CXCR4 axis might be a promising therapeutic strategy to manage prostate cancer bone metastasis.

• AIP4
• CXCR4
• bone metastasis
• prostate cancer
• wild-type p53

• negative feedback
• oscillatory dynamics
• p53 models
• positive feedback
• spatial models
• time delays

As a crucial organ, the lung is exposed to various harmful agents that may induce inflammation and oxidative stress, which may cause chronic or acute lung injury. Nigella sativa, also known as black seed, has been widely used to treat various diseases and is one of the most extensively researched medicinal plants. Thymoquinone (TQ) is the main component of black seed volatile oil and has been proven to have antioxidant, anti-inflammatory, and antineoplastic properties. The potential therapeutic properties of TQ against various pulmonary disorders have been studied in both in vitro and in vivo studies. Furthermore, the application of nanotechnology may increase drug solubility, cellular absorption, drug release (sustained or control), and drug delivery to lung tissue target sites. As a result, fabricating TQ as nanoparticles (NPs) is a potential therapeutic approach against a variety of lung diseases. In this current review, we summarize recent findings on the efficacy of TQ and its nanotypes in lung disorders caused by immunocompromised conditions such as cancer, diabetes, gastric ulcers, and other neurodegenerative diseases. It is concluded that TQ nanoparticles with anti-inflammatory, antioxidant, antiasthma, and antitumor activity may be safely applied to treat lung disorders. However, more research is required before TQ nanoparticles can be used as pharmaceutical preparations in human studies.

• anticancer activity
• antimicrobial activity
• bioavailability
• drug delivery
• lung disease
• molecular potential
• nanoparticle
• thymoquinone

Oral cancer is highly prevalent in India and is the most frequent cancer type among Indian males. It is also very common in southeast Asia. India has participated in the International Cancer Genome Consortium (ICGC) and some national initiatives to generate large-scale genomic data on oral cancer patients and analyze to identify associations and systematically catalog the associated variants. We have now created an open, web-accessible database of these variants found significantly associated with Indian oral cancer patients, with a user-friendly interface to enable easy mining. We have value added to this database by including relevant data collated from various sources on other global populations, thereby providing opportunities of comparative geographical and/or ethnic analyses. Currently, no other database of similar nature is available on oral cancer. We have developed Database of GENomic Variants of Oral Cancer, a browsable online database framework for storage, retrieval and analysis of large-scale data on genomic variants and make it freely accessible to the scientific community. Presently, the web-accessible database allows potential users to mine data on ∼24 million clinically relevant somatic and germline variants derived from exomes (n = 100) and whole genomes (n = 5) of Indian oral cancer patients; all generated by us. Variant data from The Cancer Genome Atlas and data manually curated from peer-reviewed publications were also incorporated into the database for comparative analyses. It allows users to query the database by a single gene, multiple genes, multiple variant sites, genomic region, patient ID and pathway identities.

Database URL: http://research.nibmg.ac.in/dbcares/dbgenvoc/

• AKT
• ITGB4
• NEU1
• cell migration
• p53-R273H

Human papillomavirus (HPV) 16 E6 has been proved to increase the radiosensitivity and lead to the EGFR overexpression in cervical cancer cells. In this study, to investigate the inhibition of nimotuzumab-mediated EGFR blockade combined with radiotherapy, we established a C33A cervical squamous cell line overexpressed HPV16-E6 and a nude mouse model bearing these cell lines. The CCK-8 assay was used to detect the effects of various treatments on the proliferation of C33A cells. Flow cytometry was used to detect the rates of apoptosis and cell cycle arrest. Gene transcription and protein expression were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot, respectively. Immunohistochemical staining was used to evaluate protein expression in tumor tissue. We revealed that E6-overexpressing C33A cells grew faster and were more sensitive to radiotherapy than control cells in vitro and in vivo. The expression levels of EGFR, as well as those of downstream signaling molecules AKT and ERK 1/2, were significantly upregulated in C33A cells that overexpressed E6. We observed that nimotuzumab combined with radiotherapy could enhance the inhibition of C33A cell growth induced by E6, both in vitro and in vivo. We also observed enhanced effect after combination on G2/M cell cycle arrest and apoptosis in E6-overexpressing C33A cells. Furthermore, the combined therapy of nimotuzumab and radiation remarkably reduced the protein expression levels of EGFR, AKT, ERK 1/2 in vitro, and in vivo. In conclusion, HPV16 E6 expression is positively correlated with levels of EGFR, AKT, and ERK 1/2 protein expression. The combined treatment with nimotuzumab and radiotherapy to enhance radiosensitivity in E6-positive cervical squamous cell carcinoma was related to enhanced G2/M cell cycle arrest and caspase-related apoptosis.

• cervical squamous cell carcinoma
• epidermal growth factor receptor
• human papillomavirus
• nimotuzumab
• radiosensitivity

• METABRIC
• breast cancer
• machine learning
• p53 gain of function
• pseudomutant p53

• Breast Neoplasms/genetics
• Female
• Gene Expression Profiling
• Gene Expression Regulation, Neoplastic
• Humans
• Ki-67 Antigen/metabolism
• Mutant Proteins/genetics
• Mutant Proteins/metabolism
• Mutation/genetics
• Receptor, ErbB-2/metabolism
• Receptors, Estrogen/metabolism
• Tumor Suppressor Protein p53/genetics

• 29567 Cancer Research UK
• Dr. Miriam and Sheldon G. Adelson Medical Research Foundation

• P53
• TP53
• acute myeloid leukemia
• leukemia
• therapy

• Genes, p53/genetics
• Genes, p53/physiology
• Humans
• Leukemia, Myeloid, Acute/genetics
• Leukemia, Myeloid, Acute/metabolism
• Mutation
• Tumor Suppressor Protein p53/genetics

• P01 AG031862 NIA NIH HHS
• P30 CA030199 NCI NIH HHS
• NIH/NCI P30 CA030199 NCI NIH HHS
• P01 AG031862-11 NIA NIH HHS

• DNA repair
• DNA replication
• Hepatocellular carcinoma
• NEIL1
• Polymerase zeta

• Aflatoxins/toxicity
• Animals
• Carcinogenesis/chemically induced
• Carcinogenesis/genetics
• Carcinoma, Hepatocellular/chemically induced
• Carcinoma, Hepatocellular/genetics
• Carcinoma, Hepatocellular/pathology
• Humans
• Liver Neoplasms/chemically induced
• Liver Neoplasms/genetics
• Liver Neoplasms/pathology
• Mutagenesis/drug effects
• Mutagenesis/genetics

• R56 ES027632 NIEHS NIH HHS
• R01 CA055678 NCI NIH HHS
• R56 ES029357 NIEHS NIH HHS
• S10 RR019022 NCRR NIH HHS
• R01 ES029357 NIEHS NIH HHS

• Gallbladder cancer
• mutation
• tumor suppressor gene
• proto-oncogene
• Peru

• aggregation
• biosensors
• cancer
• fluorescence
• peptides

Inactivation of the TP53 tumor suppressor gene is essential during cancer development and progression. Mutations of TP53 are often missense and occur in various human cancers. In some fraction of wild‐type (wt) TP53 tumors, p53 is inactivated by upregulated murine double minute homolog 2 (MDM2) and MDM4. We previously reported that simultaneous knockdown of MDM4 and MDM2 using synthetic DNA‐modified siRNAs revived p53 activity and synergistically inhibited in vitro cell growth in cancer cells with wt TP53 and high MDM4 expression (wtTP53/highMDM4). In the present study, MDM4/MDM2 double knockdown with the siRNAs enhanced 5‐fluorouracil (5‐FU)‐induced p53 activation, arrested the cell cycle at G₁ phase, and potentiated the antitumor effect of 5‐FU in wtTP53/highMDM4 human colon (HCT116 and LoVo) and gastric (SNU‐1 and NUGC‐4) cancer cells. Exposure to 5‐FU alone induced MDM2 as well as p21 and PUMA by p53 activation. As p53‐MDM2 forms a negative feedback loop, enhancement of the antitumor effect of 5‐FU by MDM4/MDM2 double knockdown could be attributed to blocking of the feedback mechanism in addition to direct suppression of these p53 antagonists. Intratumor injection of the MDM4/MDM2 siRNAs suppressed in vivo tumor growth and boosted the antitumor effect of 5‐FU in an athymic mouse xenograft model using HCT116 cells. These results suggest that a combination of MDM4/MDM2 knockdown and conventional cytotoxic drugs could be a promising treatment strategy for wtTP53/highMDM4 gastrointestinal cancers.

• 5-fluorouracil
• MDM4
• colon cancer
• gastric cancer
• p53

• CAVER analyst
• HADDOCK
• active tunnel
• molecular dynamics (MD)
• structural perturbation
• tumor suppressor

• HPV16
• anti-miR-182
• apoptosis
• cervical cancer
• siRNA

• head and neck cancer metastasis
• human papillomavirus (HPV)
• lung cancer
• next generation sequencing
• p53

The excision of 8-oxoguanine (oxoG) by the human 8-oxoguanine DNA glycosylase 1 (hOGG1) base-excision repair enzyme was studied by using the QM/MM (M06-2X/6-31G(d,p):OPLS2005) calculation method and nuclear magnetic resonance (NMR) spectroscopy. The calculated glycosylase reaction included excision of the oxoG base, formation of Lys249-ribose enzyme–substrate covalent adduct and formation of a Schiff base. The formation of a Schiff base with ΔG^# = 17.7 kcal/mol was the rate-limiting step of the reaction. The excision of the oxoG base with ΔG^# = 16.1 kcal/mol proceeded via substitution of the C1΄-N9 N-glycosidic bond with an H-N9 bond where the negative charge on the oxoG base and the positive charge on the ribose were compensated in a concerted manner by NH₃⁺(Lys249) and CO₂⁻(Asp268), respectively. The effect of Asp268 on the oxoG excision was demonstrated with ¹H NMR for WT hOGG1 and the hOGG1(D268N) mutant: the excision of oxoG was notably suppressed when Asp268 was mutated to Asn. The loss of the base-excision function was rationalized with QM/MM calculations and Asp268 was confirmed as the electrostatic stabilizer of ribose oxocarbenium through the initial base-excision step of DNA repair. The NMR experiments and QM/MM calculations consistently illustrated the base-excision reaction operated by hOGG1.

Traditional prognostic indicators of breast cancer, i.e. lymph node diffusion, tumor size, grading and estrogen receptor expression, are inadequate predictors of metastatic relapse. Thus, additional prognostic parameters appear urgently needed. Individual oncogenic determinants have largely failed in this endeavour. Only a few individual tumor growth drivers, e.g. mutated p53, Her-2, E-cadherin, Trops, did reach some prognostic/predictive power in clinical settings. As multiple factors are required to drive solid tumor progression, clusters of such determinants were expected to become stronger indicators of tumor aggressiveness and malignant progression than individual parameters. To identify such prognostic clusters, we went on to coordinately analyse molecular and histopathological determinants of tumor progression of post-menopausal breast cancers in the framework of a multi-institutional case series/case-control study.

A multi-institutional series of 217 breast cancer cases was analyzed. Twenty six cases (12 %) showed disease relapse during follow-up. Relapsed cases were matched with a set of control patients by tumor diameter, pathological stage, tumor histotype, age, hormone receptors and grading. Histopathological and molecular determinants of tumor development and aggressiveness were then analyzed in relapsed versus non-relapsed cases. Stepwise analyses and model structure fitness assessments were carried out to identify clusters of molecular alterations with differential impact on metastatic relapse.

p53, Bcl-2 and cathepsin D were shown to be coordinately associated with unique levels of relative risk for disease relapse. As many Ras downstream targets, among them matrix metalloproteases, are synergistically upregulated by mutated p53, whole-exon sequence analyses were performed for TP53, Ki-RAS and Ha-RAS, and findings were correlated with clinical phenotypes. Notably, TP53 insertion/deletion mutations were only detected in relapsed cases. Correspondingly, Ha-RAS missense oncogenic mutations were only found in a subgroup of relapsing tumors.

We have identified clusters of specific molecular alterations that greatly improve prognostic assessment with respect to singularly-analysed indicators. The combined analysis of these multiple tumor-relapse risk factors promises to become a powerful approach to identify patients subgroups with unfavourable disease outcome.

The online version of this article (doi:10.1186/s12885-016-2713-3) contains supplementary material, which is available to authorized users.

• Bcl-2
• Breast cancer
• Cathepsin D
• Metastatic relapse
• Prognostic indicators
• RAS
• TP53

The records are not clear, but Man has been sheltering the cat inside his home for over 12,000 years. The close proximity of this companion animal, however, goes beyond sharing the same roof; it extends to the great similarity found at the cellular and molecular levels. Researchers have found a striking resemblance between subtypes of feline mammary tumors and their human counterparts that goes from the genes to the pathways involved in cancer initiation and progression. Spontaneous cat mammary pre-invasive intraepithelial lesions (hyperplasias and neoplasias) and malignant lesions seem to share a wide repertoire of molecular features with their human counterparts. In the present review, we tried to compile all the genetics aspects published (i.e., chromosomal alterations, critical cancer genes and their expression) regarding cat mammary tumors, which support the cat as a valuable alternative in vitro cell and animal model (i.e., cat mammary cell lines and the spontaneous tumors, respectively), but also to present a critical point of view of some of the issues that really need to be investigated in future research.

• cancer critical genes
• cell and animal model
• chromosome rearrangements
• feline mammary carcinomas
• targeting therapies

Translational regulation has been shown to play an important role in cancer and tumor progression. Despite this fact, the role of translational control in cancer is an understudied and under appreciated field, most likely due to the technological hurdles and paucity of methods available to establish that changes in protein levels are due to translational regulation. Tumors are subjected to many adverse stress conditions such as hypoxia or starvation. Under stress conditions, translation is globally downregulated through several different pathways in order to conserve energy and nutrients. Many of the proteins that are synthesized during stress in order to cope with the stress use a non-canonical or cap-independent mechanism of initiation. Tumor cells have utilized these alternative mechanisms of translation initiation to promote survival during tumor progression. This review will specifically discuss the role of cap-independent translation initiation, which relies on an internal ribosome entry site (IRES) to recruit the ribosomal subunits internally to the messenger RNA. We will provide an overview of the role of IRES-mediated translation in cancer by discussing the types of genes that use IRESs and the conditions under which these mechanisms of initiation are used. We will specifically focus on three well-studied examples: Apaf-1, p53, and c-Jun, where IRES-mediated translation has been demonstrated to play an important role in tumorigenesis or tumor progression.

• Apaf-1
• IRES
• apoptosis
• c-Jun
• cap-independent
• p53
• translation
• tumorigenesis

• Deletion
• TP53 gene
• duplication
• multiplex ligation-dependent probe amplification
• transitional cell carcinoma

• Adult
• Aged
• Carcinoma, Transitional Cell/diagnosis
• Carcinoma, Transitional Cell/genetics
• Exons
• Female
• Gene Duplication
• Humans
• Male
• Middle Aged
• Neoplasm Grading
• Neoplasm Staging
• Nucleic Acid Amplification Techniques
• Sequence Deletion
• Tumor Suppressor Protein p53/genetics
• Urinary Bladder Neoplasms/diagnosis
• Urinary Bladder Neoplasms/genetics

• Hashimoto’s thyroiditis
• Single nucleotide polymorphism (SNP)
• p53
• p53 mutations

• Adult
• Exons/genetics
• Female
• Genetic Predisposition to Disease
• Hashimoto Disease/genetics
• Humans
• Male
• Middle Aged
• Polymorphism, Single Nucleotide/genetics
• Tumor Suppressor Protein p53/genetics
• White People/genetics

• AR
• EGFR
• MMP-9
• NGAL
• Regulatory RNAs
• TP53

The functional inactivation of TP53 and Rb tumor suppressor proteins by the HPV-derived E6 and E7 oncoproteins is likely an important step in cervical carcinogenesis. We have previously shown siRNA technology to selectively silence both E6/E7 oncogenes and demonstrated that the synthetic siRNAs could specifically block its expression in HPV-positive cervical cancer cells. Herein, we investigated the potentiality of E6/E7 siRNA candidates as radiosensitizers of radiotherapy for the human cervical carcinomas. HeLa and SiHa cells were transfected with HPV E6/E7 siRNA; the combined cytotoxic effect of E6/E7 siRNA and radiation was assessed by using the cell viability assay, flow cytometric analysis and the senescence-associated β-galactosidase (SA-β-Gal) assay. In addition, we also investigated the effect of combined therapy with irradiation and E6/E7 siRNA intravenous injection in an in vivo xenograft model. Combination therapy with siRNA and irradiation efficiently retarded tumor growth in established tumors of human cervical cancer cell xenografted mice. In addition, the chemically-modified HPV16 and 18 E6/E7 pooled siRNA in combination with irradiation strongly inhibited the growth of cervical cancer cells. Our results indicated that simultaneous inhibition of HPV E6/E7 oncogene expression with radiotherapy can promote potent antitumor activity and radiosensitizing activity in human cervical carcinomas.

• Concurrent Chemoradiation therapy (CCRT)
• E6
• E7
• cervical cancer
• radiosensitizer
• radiotherapy
• siRNA

Human papillomaviruses (HPVs) are small DNA viruses; some oncogenic ones can cause different types of cancer, in particular cervical cancer. HPV-associated carcinogenesis provides a classical model system for RNA interference (RNAi) based cancer therapies, because the viral oncogenes E6 and E7 that cause cervical cancer are expressed only in cancerous cells. Previous studies on the development of therapeutic RNAi facilitated the advancement of therapeutic siRNAs and demonstrated its versatility by siRNA-mediated depletion of single or multiple cellular/viral targets. Sequence-specific gene silencing using RNAi shows promise as a novel therapeutic approach for the treatment of a variety of diseases that currently lack effective treatments. However, siRNA-based targeting requires further validation of its efficacy in vitro and in vivo, for its potential off-target effects, and of the design of conventional therapies to be used in combination with siRNAs and their drug delivery vehicles. In this review we discuss what is currently known about HPV-associated carcinogenesis and the potential for combining siRNA with other treatment strategies for the development of future therapies. Finally, we present our assessment of the most promising path to the development of RNAi therapeutic strategies for clinical settings.

• HPV E6 and E7 oncogenes
• cervical cancer
• siRNA pool

DNA methylation regulates gene expression, through the inhibition/activation of gene transcription of methylated/unmethylated genes. Hence, DNA methylation profiling can capture pivotal features of gene expression in cancer tissues from patients at the time of diagnosis. In this work, we analyzed a breast cancer case series, to identify DNA methylation determinants of metastatic versus non-metastatic tumors.

CpG-island methylation was evaluated on a 56-gene cancer-specific biomarker microarray in metastatic versus non-metastatic breast cancers in a multi-institutional case series of 123 breast cancer patients. Global statistical modeling and unsupervised hierarchical clustering were applied to identify a multi-gene binary classifier with high sensitivity and specificity. Network analysis was utilized to quantify the connectivity of the identified genes.

Seven genes (BRCA1, DAPK1, MSH2, CDKN2A, PGR, PRKCDBP, RANKL) were found informative for prognosis of metastatic diffusion and were used to calculate classifier accuracy versus the entire data-set. Individual-gene performances showed sensitivities of 63–79 %, 53–84 % specificities, positive predictive values of 59–83 % and negative predictive values of 63–80 %. When modelled together, these seven genes reached a sensitivity of 93 %, 100 % specificity, a positive predictive value of 100 % and a negative predictive value of 93 %, with high statistical power. Unsupervised hierarchical clustering independently confirmed these findings, in close agreement with the accuracy measurements. Network analyses indicated tight interrelationship between the identified genes, suggesting this to be a functionally-coordinated module, linked to breast cancer progression.

Our findings identify CpG-island methylation profiles with deep impact on clinical outcome, paving the way for use as novel prognostic assays in clinical settings.

The online version of this article (doi:10.1186/s12885-015-1412-9) contains supplementary material, which is available to authorized users.

MDM2 and MDM4, a structurally related MDM2 homolog, negatively regulates expression and functions of TP53 tumor suppressor gene. To explore the precise expression patterns and function of MDM2 and MDM4 in wild-type (wt) TP53 cancer cells, we analyzed 11 various cancer cell lines with wt TP53. All cell lines exhibited deregulated expression of MDM2 and MDM4, and were divided into two distinct types; the one expressing high levels of MDM4 and another expressing low levels of MDM4. The low MDM4 type expressed higher MDM2 levels than the high MDM4 type. In cells with high MDM4 expression, knockdown of MDM4 or MDM2 reactivated TP53, and simultaneous knockdown of MDM2 and MDM4 synergistically reactivated TP53. In contrast, in cells with low MDM4 expression, knockdown of only MDM2 reactivated TP53. These results suggest that both MDM2 and MDM4 are closely involved in TP53 inactivation in cancer cells with high MDM4 expression, whereas only MDM2, and not MDM4, is a regulator of TP53 in cells with low MDM4 expression. MDM4 expression in wt TP53-tumors is a potential indicator for TP53 reactivation cancer therapy by simultaneous targeting of MDM4 and MDM2. Specific knockdown of MDM2 and MDM4 might be applicable for TP53 restoration therapy.

• MDM2
• MDM4
• TP53-reactivation
• knockdown
• p53
• siRNA

• CKD-602
• G2/M arrest
• apoptosis
• oral squamous cell carcinoma

The p53 transcription factor plays an important role in genome integrity. To perform this task, p53 regulates the transcription of genes promoting various cellular outcomes including cell cycle arrest, apoptosis or senescence. The precise regulation of this activity remains elusive as numerous mechanisms, e.g. posttranslational modifications of p53 and (non-)covalent p53 binding partners, influence the p53 transcriptional program. We developed a novel, non-invasive tool to manipulate endogenous p53. Nanobodies (Nb), raised against the DNA-binding domain of p53, allow us to distinctively target both wild type and mutant p53 with great specificity. Nb3 preferentially binds ‘structural’ mutant p53, i.e. R175H and R282W, while a second but distinct nanobody, Nb139, binds both mutant and wild type p53. The co-crystal structure of the p53 DNA-binding domain in complex with Nb139 (1.9 Å resolution) reveals that Nb139 binds opposite the DNA-binding surface. Furthermore, we demonstrate that Nb139 does not disturb the functional architecture of the p53 DNA-binding domain using conformation-specific p53 antibody immunoprecipitations, glutaraldehyde crosslinking assays and chromatin immunoprecipitation. Functionally, the binding of Nb139 to p53 allows us to perturb the transactivation of p53 target genes. We propose that reduced recruitment of transcriptional co-activators or modulation of selected post-transcriptional modifications account for these observations.