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Janghorban M, Langer EM, Wang X, Zachman D, Daniel CJ, Hooper J, Fleming WH, Agarwal A, Sears RC. The tumor suppressor phosphatase PP2A-B56α regulates stemness and promotes the initiation of malignancies in a novel murine model. PLoS One 2017; 12:e0188910. [PMID: 29190822 PMCID: PMC5708644 DOI: 10.1371/journal.pone.0188910] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 11/15/2017] [Indexed: 01/13/2023] Open
Abstract
Protein phosphatase 2A (PP2A) is a ubiquitously expressed Serine-Threonine phosphatase mediating 30–50% of protein phosphatase activity. PP2A functions as a heterotrimeric complex, with the B subunits directing target specificity to regulate the activity of many key pathways that control cellular phenotypes. PP2A-B56α has been shown to play a tumor suppressor role and to negatively control c-MYC stability and activity. Loss of B56α promotes cellular transformation, likely at least in part through its regulation of c-MYC. Here we report generation of a B56α hypomorph mouse with very low B56α expression that we used to study the physiologic activity of the PP2A-B56α phosphatase. The predominant phenotype we observed in mice with B56α deficiency in the whole body was spontaneous skin lesion formation with hyperproliferation of the epidermis, hair follicles and sebaceous glands. Increased levels of c-MYC phosphorylation on Serine62 and c-MYC activity were observed in the skin lesions of the B56αhm/hm mice. B56α deficiency was found to increase the number of skin stem cells, and consistent with this, papilloma initiation was accelerated in a carcinogenesis model. Further analysis of additional tissues revealed increased inflammation in spleen, liver, lung, and intestinal lymph nodes as well as in the skin lesions, resembling elevated extramedullary hematopoiesis phenotypes in the B56αhm/hm mice. We also observed an increase in the clonogenicity of bone marrow stem cells in B56αhm/hm mice. Overall, this model suggests that B56α is important for stem cells to maintain homeostasis and that B56α loss leading to increased activity of important oncogenes, including c-MYC, can result in aberrant cell growth and increased stem cells that can contribute to the initiation of malignancy.
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Affiliation(s)
- Mahnaz Janghorban
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Ellen M. Langer
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Xiaoyan Wang
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Derek Zachman
- Papé Family Pediatric Research Institute, Oregon Stem Cell Center, Department of Pediatrics, Portland, Oregon, United States of America
| | - Colin J. Daniel
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Jody Hooper
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - William H. Fleming
- Papé Family Pediatric Research Institute, Oregon Stem Cell Center, Department of Pediatrics, Portland, Oregon, United States of America
- Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Anupriya Agarwal
- Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Hematology & Medical Oncology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Rosalie C. Sears
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, United States of America
- Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, United States of America
- Brenden-Colson Center for Pancreatic Care, Oregon Health and Science University, Portland, Oregon, United States of America
- * E-mail:
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Jin YJ, Wang S, Cho J, Selim MA, Wright T, Mosialos G, Zhang JY. Epidermal CYLD inactivation sensitizes mice to the development of sebaceous and basaloid skin tumors. JCI Insight 2016; 1. [PMID: 27478875 DOI: 10.1172/jci.insight.86548] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The deubiquitinase-encoding gene Cyld displays a dominant genetic linkage to a wide spectrum of skin-appendage tumors, which could be collectively designated as CYLD mutant-syndrome (CYLDm-syndrome). Despite recent advances, little is understood about the molecular mechanisms responsible for this painful and difficult-to-treat skin disease. Here, we generated a conditional mouse model with epidermis-targeted expression of a catalytically deficient CYLDm through K14-Cre-mediated deletion of exon 9 (hereafter refer to CyldEΔ9/Δ9 ). CyldEΔ9/Δ9 mice were born alive but developed hair and sebaceous gland abnormalities and dental defects at 100% and 60% penetrance, respectively. Upon topical challenge with DMBA/TPA, these animals primarily developed sebaceous and basaloid tumors resembling human CYLDm-syndrome as opposed to papilloma, which is most commonly induced in WT mice by this treatment. Molecular analysis revealed that TRAF6-K63-Ubiquitination (K63-Ub), c-Myc-K63-Ub, and phospho-c-Myc (S62) were markedly elevated in CyldEΔ9/Δ9 skin. Topical treatment with a pharmacological c-Myc inhibitor induced sebaceous and basal cell apoptosis in CyldEΔ9/Δ9 skin. Consistently, c-Myc activation was readily detected in human cylindroma and sebaceous adenoma. Taken together, our findings demonstrate that CyldEΔ9/Δ9 mice represent a disease-relevant animal model and identify TRAF6 and c-Myc as potential therapeutic targets for CYLDm-syndrome.
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Affiliation(s)
- Yingai Jane Jin
- Department of Dermatology, Duke University, Duke University Medical Center, Durham, North Carolina, USA
| | - Sally Wang
- Department of Dermatology, Duke University, Duke University Medical Center, Durham, North Carolina, USA
| | - Joshua Cho
- Department of Dermatology, Duke University, Duke University Medical Center, Durham, North Carolina, USA
| | - M Angelica Selim
- Department of Pathology, Duke University, Durham, North Carolina, USA
| | - Tim Wright
- Dental School, University North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - George Mosialos
- School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Jennifer Y Zhang
- Department of Dermatology, Duke University, Duke University Medical Center, Durham, North Carolina, USA; Department of Pathology, Duke University, Durham, North Carolina, USA
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Huang PY, Balmain A. Modeling cutaneous squamous carcinoma development in the mouse. Cold Spring Harb Perspect Med 2014; 4:a013623. [PMID: 25183851 DOI: 10.1101/cshperspect.a013623] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cutaneous squamous cell carcinoma (SCC) is one of the most common cancers in Caucasian populations and is associated with a significant risk of morbidity and mortality. The classic mouse model for studying SCC involves two-stage chemical carcinogenesis, which has been instrumental in the evolution of the concept of multistage carcinogenesis, as widely applied to both human and mouse cancers. Much is now known about the sequence of biological and genetic events that occur in this skin carcinogenesis model and the factors that can influence the course of tumor development, such as perturbations in the oncogene/tumor-suppressor signaling pathways involved, the nature of the target cell that acquires the first genetic hit, and the role of inflammation. Increasingly, studies of tumor-initiating cells, malignant progression, and metastasis in mouse skin cancer models will have the potential to inform future approaches to treatment and chemoprevention of human squamous malignancies.
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Affiliation(s)
- Phillips Y Huang
- Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, California 94158
| | - Allan Balmain
- Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, California 94158
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Inoue S, Hao Z, Elia AJ, Cescon D, Zhou L, Silvester J, Snow B, Harris IS, Sasaki M, Li WY, Itsumi M, Yamamoto K, Ueda T, Dominguez-Brauer C, Gorrini C, Chio IIC, Haight J, You-Ten A, McCracken S, Wakeham A, Ghazarian D, Penn LJZ, Melino G, Mak TW. Mule/Huwe1/Arf-BP1 suppresses Ras-driven tumorigenesis by preventing c-Myc/Miz1-mediated down-regulation of p21 and p15. Genes Dev 2013; 27:1101-14. [PMID: 23699408 DOI: 10.1101/gad.214577.113] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Tumorigenesis results from dysregulation of oncogenes and tumor suppressors that influence cellular proliferation, differentiation, apoptosis, and/or senescence. Many gene products involved in these processes are substrates of the E3 ubiquitin ligase Mule/Huwe1/Arf-BP1 (Mule), but whether Mule acts as an oncogene or tumor suppressor in vivo remains controversial. We generated K14Cre;Mule(flox/flox(y)) (Mule kKO) mice and subjected them to DMBA/PMA-induced skin carcinogenesis, which depends on oncogenic Ras signaling. Mule deficiency resulted in increased penetrance, number, and severity of skin tumors, which could be reversed by concomitant genetic knockout of c-Myc but not by knockout of p53 or p19Arf. Notably, in the absence of Mule, c-Myc/Miz1 transcriptional complexes accumulated, and levels of p21CDKN1A (p21) and p15INK4B (p15) were down-regulated. In vitro, Mule-deficient primary keratinocytes exhibited increased proliferation that could be reversed by Miz1 knockdown. Transfer of Mule-deficient transformed cells to nude mice resulted in enhanced tumor growth that again could be abrogated by Miz1 knockdown. Our data demonstrate in vivo that Mule suppresses Ras-mediated tumorigenesis by preventing an accumulation of c-Myc/Miz1 complexes that mediates p21 and p15 down-regulation.
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Affiliation(s)
- Satoshi Inoue
- The Campbell Family Institute for Breast Cancer Research, Ontario Cancer Institute, University Health Network, Toronto, Ontario M5G 2C1, Canada
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Niemann C, Horsley V. Development and homeostasis of the sebaceous gland. Semin Cell Dev Biol 2012; 23:928-36. [PMID: 22960253 DOI: 10.1016/j.semcdb.2012.08.010] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 08/15/2012] [Accepted: 08/24/2012] [Indexed: 12/16/2022]
Abstract
The important role of epidermal appendages especially the sebaceous gland has only recently been recognized. In particular, it has been convincingly shown that normal development and maintenance of the sebaceous gland are required for skin homeostasis since atrophic sebaceous glands and disturbances in sebaceous lipid composition result in major defects of the physiological barrier and maintenance of the skin. Consequently, it is important to unravel the signaling network controlling proper sebaceous lineage differentiation in mammalian skin and to understand the underlying mechanisms leading to severe skin diseases, including abnormal proliferation and differentiation of the gland, defects of the lipid metabolism and barrier, as well as sebaceous tumor formation. Over the last years, results from transgenic and knock out mouse models manipulating distinct signaling pathways in the skin as well as the detailed analysis of human sebaceous gland-derived cell lines provided new insights into crucial mediators balancing proliferation and differentiation of the sebaceous gland. Here, we discuss our current knowledge of in vivo mechanisms of sebaceous gland development, maintenance and disorders and highlight recent contributions to the field of sebaceous gland biology.
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Affiliation(s)
- Catherin Niemann
- Center for Molecular Medicine Cologne, University of Cologne, Germany.
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Li S, Park H, Trempus CS, Gordon D, Liu Y, Cotsarelis G, Morris RJ. A keratin 15 containing stem cell population from the hair follicle contributes to squamous papilloma development in the mouse. Mol Carcinog 2012; 52:751-9. [PMID: 22431489 DOI: 10.1002/mc.21896] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 02/13/2012] [Indexed: 11/10/2022]
Abstract
The multistage model of nonmelanoma skin carcinogenesis has contributed significantly to our understanding of epithelial cancer in general. We used the Krt1-15CrePR1;R26R transgenic mouse to determine the contribution of keratin 15+ cells from the hair follicle to skin tumor development by following the labeled progeny of the keratin 15 expressing cells into papillomas. We present three novel observations. First, we found that keratin 15 expressing cells contribute to most of the papillomas by 20 weeks of promotion. Second, in contrast to the transient behavior of labeled keratin 15-derived progeny in skin wound healing, keratin 15 progeny persist in papillomas, and some malignancies for many months following transient induction of the reporter gene. Third, papillomas have surprising heterogeneity not only in their cellular composition, but also in their expression of the codon 61 signature Ha-ras mutation with approximately 30% of keratin 15-derived regions expressing the mutation. Together, these results demonstrate that keratin 15 expressing cells of the hair follicle contribute to cutaneous papillomas with long term persistence and a subset of which express the Ha-ras signature mutation characteristic of initiated cells.
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Affiliation(s)
- Shulan Li
- Department of Dermatology, Columbia University Medical Center, New York, New York
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Kanwar SS, Poolla A, Majumdar APN. Regulation of colon cancer recurrence and development of therapeutic strategies. World J Gastrointest Pathophysiol 2012; 3:1-9. [PMID: 22368781 PMCID: PMC3284520 DOI: 10.4291/wjgp.v3.i1.1] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 09/08/2011] [Accepted: 02/08/2012] [Indexed: 02/06/2023] Open
Abstract
Recurrence of colon cancer still remains a major issue which affects nearly 50% of patients treated by conventional therapeutics. Although the underlying causative factor(s) is not fully understood, development of drug-resistance has been associated with induction of cancer stem or stem-like cells (CSCs) which constitute a small sub-population of tumor cells known to be highly resistant to chemotherapy. In fact, the discovery of CSCs in a variety of tumors (including colon cancer) has changed the view of carcinogenesis and therapeutic strategies. Emerging reports have indicated that to improve patient outcomes, conventional anticancer therapies should be replaced with specific approaches targeting CSCs. Thus, therapeutic strategies that specifically target CSCs are being sought to reduce the risk of relapse and metastasis. In order to specifically target colon CSCs (while sparing somatic intestinal stem cells), it is critical to identify unique deregulated pathways responsible for self-renewal of CSCs and colon cancer recurrence. Colon CSCs present a unique opportunity to better understand the biology of solid tumors. Thus, a better understanding of the clinical signs and symptoms of colon cancer patients (undergoing surgery or chemotherapy) during perioperative periods, along with the underlying regulatory events affecting the stem/progenitor cell self-renewal and differentiation of colon epithelial cells, is of immense importance. In this review we discuss the implication of clinical factors and the emerging role of CSCs during recurrence of colon cancer along with the development of new therapeutic strategies involving the use of natural agents.
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