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Dhar S, Kumar A, Li K, Tzivion G, Levenson AS. Resveratrol regulates PTEN/Akt pathway through inhibition of MTA1/HDAC unit of the NuRD complex in prostate cancer. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1853:265-75. [PMID: 25447541 DOI: 10.1016/j.bbamcr.2014.11.004] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 10/22/2014] [Accepted: 11/04/2014] [Indexed: 01/31/2023]
Abstract
Metastasis associated protein 1 (MTA1) is a component of the nucleosome remodeling and deacetylating (NuRD) complex which mediates gene silencing and is overexpressed in several cancers. We reported earlier that resveratrol, a dietary stilbene found in grapes, can down-regulate MTA1. In the present study, we show that PTEN is inactivated by MTA1 in prostate cancer cells. Further, we show that resveratrol promotes acetylation and reactivation of PTEN via inhibition of the MTA1/HDAC complex, resulting in inhibition of the Akt pathway. In addition, we show that MTA1 knockdown is sufficient to augment acetylation of PTEN indicating a crucial role of MTA1 itself in the regulation of PTEN acetylation contributing to its lipid phosphatase activity. Acetylated PTEN preferentially accumulates in the nucleus where it binds to MTA1. We also show that MTA1 interacts exclusively with PTEN acetylated on Lys¹²⁵ and Lys¹²⁸, resulting in diminished p-Akt levels. Finally, using orthotopic prostate cancer xenografts, we demonstrate that both resveratrol treatment and MTA1 knockdown enhance PTEN levels leading to a decreased p-Akt expression and proliferation index. Taken together, our results indicate that MTA1/HDAC unit is a negative regulator of PTEN which facilitates survival pathways and progression of prostate cancer and that resveratrol can reverse this process through its MTA1 inhibitory function.
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Affiliation(s)
- Swati Dhar
- Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA
| | - Avinash Kumar
- Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA
| | - Kun Li
- Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA
| | - Guri Tzivion
- Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA
| | - Anait S Levenson
- Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA; Department of Pathology, University of Mississippi Medical Center, Jackson, MS, USA.
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Abstract
Deubiquitinases (DUBs) play important roles and therefore are potential drug targets in various diseases including cancer and neurodegeneration. In this review, we recapitulate structure-function studies of the most studied DUBs including USP7, USP22, CYLD, UCHL1, BAP1, A20, as well as ataxin 3 and connect them to regulatory mechanisms and their growing protein interaction networks. We then describe DUBs that have been associated with endocrine carcinogenesis with a focus on prostate, ovarian, and thyroid cancer, pheochromocytoma, and adrenocortical carcinoma. The goal is enhancing our understanding of the connection between dysregulated DUBs and cancer to permit the design of therapeutics and to establish biomarkers that could be used in diagnosis and prognosis.
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Affiliation(s)
- Roland Pfoh
- Department of BiologyYork University, 4700 Keele Street, Toronto, Ontario, Canada, M3J1P3
| | - Ira Kay Lacdao
- Department of BiologyYork University, 4700 Keele Street, Toronto, Ontario, Canada, M3J1P3
| | - Vivian Saridakis
- Department of BiologyYork University, 4700 Keele Street, Toronto, Ontario, Canada, M3J1P3
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103
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Abstract
The importance of PTEN in cellular function is underscored by the frequency of its deregulation in cancer. PTEN tumor-suppressor activity depends largely on its lipid phosphatase activity, which opposes PI3K/AKT activation. As such, PTEN regulates many cellular processes, including proliferation, survival, energy metabolism, cellular architecture, and motility. More than a decade of research has expanded our knowledge about how PTEN is controlled at the transcriptional level as well as by numerous posttranscriptional modifications that regulate its enzymatic activity, protein stability, and cellular location. Although the role of PTEN in cancers has long been appreciated, it is also emerging as an important factor in other diseases, such as diabetes and autism spectrum disorders. Our understanding of PTEN function and regulation will hopefully translate into improved prognosis and treatment for patients suffering from these ailments.
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Affiliation(s)
- Carolyn A Worby
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093-0721;
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104
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Characterization of nuclear PTEN and its post translational modifications. Methods 2015; 77-78:104-11. [PMID: 25616216 DOI: 10.1016/j.ymeth.2015.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/09/2015] [Accepted: 01/12/2015] [Indexed: 11/21/2022] Open
Abstract
Somatic loss-of-function mutations of PTEN are found in a variety of human malignancies. Our recent work demonstrated that the nuclear function of PTEN is implicated in the maintenance of genome integrity. Proper subcellular localization of PTEN following genotoxic stress is coordinated by a cellular mechanism that involves post-translational modification by SUMOylation and ATM-mediated phosphorylation. Here we summarize biochemical and cell-based methodologies that can be used to characterize the SUMOylation and phosphorylation state of nuclear PTEN in the context of DNA damage. In addition, we describe assays to determine the biological function of SUMO-PTEN in homologous recombination DNA repair. These methods will help elucidate the precise molecular mechanisms of PTEN's role in the maintenance of genomic stability.
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105
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Zhang W, Neo SP, Gunaratne J, Poulsen A, Boping L, Ong EH, Sangthongpitag K, Pendharkar V, Hill J, Cohen SM. Feedback regulation on PTEN/AKT pathway by the ER stress kinase PERK mediated by interaction with the Vault complex. Cell Signal 2014; 27:436-42. [PMID: 25530215 DOI: 10.1016/j.cellsig.2014.12.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Revised: 12/01/2014] [Accepted: 12/15/2014] [Indexed: 01/06/2023]
Abstract
The high proliferation rate of cancer cells, together with environmental factors such as hypoxia and nutrient deprivation can cause Endoplasmic Reticulum (ER) stress. The protein kinase PERK is an essential mediator in one of the three ER stress response pathways. Genetic and pharmacological inhibition of PERK has been reported to limit tumor growth in xenograft models. Here we provide evidence that inactive PERK interacts with the nuclear pore-associated Vault complex protein and that this compromises Vault-mediated nuclear transport of PTEN. Pharmacological inhibition of PERK under ER stress results is abnormal sequestration of the Vault complex, leading to increased cytoplasmic PTEN activity and lower AKT activation. As the PI3K/PTEN/AKT pathway is crucial for many aspects of cell growth and survival, this unexpected effect of PERK inhibitors on AKT activity may have implications for their potential use as therapeutic agents.
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Affiliation(s)
- Wei Zhang
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Suat Peng Neo
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Jayantha Gunaratne
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Anders Poulsen
- Experimental Therapeutics Center, 31 Biopolis Way, Singapore 138669, Singapore
| | - Liu Boping
- Experimental Therapeutics Center, 31 Biopolis Way, Singapore 138669, Singapore
| | - Esther Hongqian Ong
- Experimental Therapeutics Center, 31 Biopolis Way, Singapore 138669, Singapore
| | | | - Vishal Pendharkar
- Experimental Therapeutics Center, 31 Biopolis Way, Singapore 138669, Singapore
| | - Jeffrey Hill
- Experimental Therapeutics Center, 31 Biopolis Way, Singapore 138669, Singapore
| | - Stephen M Cohen
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673, Singapore; Department of Biological Sciences, National University of Singapore, 117543, Singapore.
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Abstract
The intracellular location and regulation of proteins within each cell is critically important and is typically deregulated in disease especially cancer. The clinical hypothesis for inhibiting the nucleo-cytoplasmic transport is based on the dependence of certain key proteins within malignant cells. This includes a host of well-characterized tumor suppressor and oncoproteins that require specific localization for their function. This aberrant localization of tumour suppressors and oncoproteins results in their their respective inactivation or over-activation. This incorrect localization occurs actively via the nuclear pore complex that spans the nuclear envelope and is mediated by transport receptors. Accordingly, given the significant need for novel, specific disease treatments, the nuclear envelope and the nuclear transport machinery have emerged as a rational therapeutic target in oncology to restore physiological nucleus/cytoplasmic homeostasis. Recent evidence suggests that this approach might be of substantial therapeutic use. This review summarizes the mechanisms of nucleo-cytoplasmic transport, its role in cancer biology and the therapeutic potential of targeting this critical cellular process.
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Affiliation(s)
- Richard Hill
- Regenerative Medicine Program, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, Portugal
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107
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Tait IS, Li Y, Lu J. Effects of PTEN on the longevity of cultured human umbilical vein endothelial cells: the role of antioxidants. Int J Mol Med 2014; 35:277-84. [PMID: 25395086 DOI: 10.3892/ijmm.2014.1999] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 11/03/2014] [Indexed: 11/06/2022] Open
Abstract
Ageing is a major cause of illness, disease and mortality, mainly due to the shortening of telomeres, resulting in cells undergoing senescence and apoptosis. Increasing autophagy and the levels of antioxidants removes oxidants that cause DNA and telomere damage, thus reducing the rate at which telomeres shorten, resulting in a longer cellular lifespan. Phosphatase and tensin homolog (PTEN) has been shown to increase the lifespan of organisms by upregulating pathways involved in DNA damage repair, autophagy/antioxidants. The aim of this study was to investigate the effects of the overexpression of PTEN on the longevity of human cell cultures by examining the increase in antioxidant potential. Human umbilical vein endothelial cell (HUVEC) cultures were transfected with PTEN plasmids using lipofectamine. An assay was performed to quantify the protein levels of PTEN and the antioxidant potential of the cell cultures. The cell cultures were maintained until senescence occurred in order to determine longevity. The results of each assay were then compared and correlated with each other and with the longevity of the cells. The transfected cultures showed a significant increase in PTEN protein levels, total antioxidant potential and longevity (all P-values <0.001) compared with the non-transfected cell cultures. The correlation coefficient between cell longevity and PTEN levels was 0.8727; and the correlation coefficient between cell longevity and antioxidant potential was 0.6564. The successful transfection of PTEN led to an increase in PTEN levels, antioxidant potential and an increased cellular longevity. This study demonstrates that there is a potential for PTEN to be used to extend human longevity. This can lay the foundation for further studies to be carried out on humans involving PTEN and longevity.
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Affiliation(s)
- Izak S Tait
- School of Applied Sciences, Auckland University of Technology, Auckland 1010, New Zealand
| | - Yan Li
- School of Applied Sciences, Auckland University of Technology, Auckland 1010, New Zealand
| | - Jun Lu
- School of Applied Sciences, Auckland University of Technology, Auckland 1010, New Zealand
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Minami A, Nakanishi A, Ogura Y, Kitagishi Y, Matsuda S. Connection between Tumor Suppressor BRCA1 and PTEN in Damaged DNA Repair. Front Oncol 2014; 4:318. [PMID: 25426449 PMCID: PMC4226230 DOI: 10.3389/fonc.2014.00318] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 10/24/2014] [Indexed: 12/19/2022] Open
Abstract
Genomic instability finally induces cell death or apoptosis. The tumor suppressor, phosphatase and tensin homolog on chromosome 10 (PTEN), is a dual-specificity phosphatase, which has protein phosphatase activity and lipid phosphatase activity that antagonizes PI3K activity. Cells that lack PTEN have constitutively higher levels of PIP3 and activated downstream PI3K/AKT targets. BRCA1, a well-known breast cancer tumor suppressor, is to associate with breast cancer risk and genetic susceptibility. Many studies have demonstrated that PTEN, as well as BRCA1, plays a critical role in DNA damage responses. The BRCA1 functionally cooperates with PTEN and might be an essential blockage in the development of several tumors. Actually, the PTEN and BRCA1 genes are recognized as one of the most frequently deleted and/or mutated in many human cancers. The PI3K/AKT pathway is constitutively active in BRCA1-defective human cancer cells. Loss or decrease of these PTEN or BRCA1 function, by either mutation or reduced expression, has a role in various tumor developments. This review summarizes recent findings of the function of BRCA1 and PTEN involved in genomic stability and cancer cell signaling.
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Affiliation(s)
- Akari Minami
- Department of Food Science and Nutrition, Nara Women's University , Nara , Japan
| | - Atsuko Nakanishi
- Department of Food Science and Nutrition, Nara Women's University , Nara , Japan
| | - Yasunori Ogura
- Department of Food Science and Nutrition, Nara Women's University , Nara , Japan
| | - Yasuko Kitagishi
- Department of Food Science and Nutrition, Nara Women's University , Nara , Japan
| | - Satoru Matsuda
- Department of Food Science and Nutrition, Nara Women's University , Nara , Japan
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109
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Is Cytoplasmic PTEN a Specific Target for Neuronal Survival? Mol Neurobiol 2014; 52:1758-1764. [DOI: 10.1007/s12035-014-8922-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 09/30/2014] [Indexed: 01/16/2023]
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Malaney P, Uversky VN, Davé V. Identification of intrinsically disordered regions in PTEN and delineation of its function via a network approach. Methods 2014; 77-78:69-74. [PMID: 25449897 DOI: 10.1016/j.ymeth.2014.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 10/01/2014] [Accepted: 10/06/2014] [Indexed: 12/14/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) are proteins that lack stable higher order structures for the entire protein molecule or a significant portion of it. The discovery of IDPs evolved as an antithesis to the conventional structure-function paradigm wherein a higher order structure dictates protein function. Over the last decade, a number of proteins with functionally relevant unstructured regions have been discovered, which includes tumor suppressor PTEN. The protein domains that lack structure provide "hot-spots" for post-translational modifications (PTMs) and protein-protein interactions (PPIs), which facilitate their regulation and participation in multiple cellular processes. Consequently, dysregulation in IDPs contribute to aberrant cellular pathophysiology. Herein, we present PTEN and its translational isoform PTEN-L as a hybrid protein possessing ordered domain and intrinsically disordered C-terminal and an N-terminal tails. We review the role of intrinsic disorder in PTEN function and propose a methodology for the use of intrinsic disorder to study PTEN-regulated higher order protein-networks by associating basic principles of network biology to functional pathway analysis at the systems level.
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Affiliation(s)
- Prerna Malaney
- Department of Pathology and Cell Biology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, United States
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, United States; Institute for Biological Instrumentation, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia; Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah 22254, Saudi Arabia
| | - Vrushank Davé
- Department of Pathology and Cell Biology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, United States; Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, United States.
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111
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Bononi A, Pinton P. Study of PTEN subcellular localization. Methods 2014; 77-78:92-103. [PMID: 25312582 PMCID: PMC4396696 DOI: 10.1016/j.ymeth.2014.10.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/28/2014] [Accepted: 10/02/2014] [Indexed: 01/26/2023] Open
Abstract
The tumor suppressor PTEN is a key regulator of a plethora of cellular processes that are crucial in cancer development. Through its lipid phosphatase activity PTEN suppresses the PI3K/AKT pathway to govern cell proliferation, growth, migration, energy metabolism and death. The repertoire of roles fulfilled by PTEN has recently been expanded to include crucial functions in the nucleus, where it favors genomic stability and restrains cell cycle progression, as well as protein phosphatase dependent activity at the endoplasmic reticulum (ER) and mitochondria-associated membranes (MAMs), where PTEN interacts with the inositol 1,4,5-trisphosphate receptors (IP3Rs) and regulates Ca2+ release from the ER and sensitivity to apoptosis. Indeed, PTEN is present in definite subcellular locations where it performs distinct functions acting on specific effectors. In this review, we summarize recent advantages in methods to study PTEN subcellular localization and the distinct biological functions of PTEN in different cellular compartments. A deeper understanding of PTEN’s compartmentalized-functions will guide the rational design of novel therapies.
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Affiliation(s)
- Angela Bononi
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Ferrara, Italy.
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PI3K/mTOR signaling in mesothelioma patients treated with induction chemotherapy followed by extrapleural pneumonectomy. J Thorac Oncol 2014; 9:239-47. [PMID: 24419422 DOI: 10.1097/jto.0000000000000055] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION The prognostic significance of activity biomarkers within the phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) signaling pathway was assessed in two independent cohorts of malignant pleural mesothelioma (MPM) patients uniformly treated with a multimodal approach. We specifically assessed expression signatures in a unique set of pre- and postchemotherapy tumor samples. METHODS Biomarker expression was assessed in samples of two independent cohorts of 107 (cohort 1) and 46 (cohort 2) MPM cases uniformly treated with platinum-based induction chemotherapy followed by extrapleural pneumonectomy from two different institutions, assembled on tissue microarrays. Expression levels of phosphatase and tensin homologue (PTEN), phospho-mTOR, and p-S6 in addition to marker of proliferation (Ki-67) and apoptosis (cleaved caspase-3) were evaluated by immunohistochemistry and correlated with overall survival (OAS) and progression-free survival (PFS). To assess PTEN genomic status, fluorescence in situ hybridization was performed. RESULTS Survival analysis showed that high p-S6 and Ki-67 expression in samples of treatment naïve patients of cohort 1 was associated with shorter PFS (p = 0.02 and p = 0.04, respectively). High Ki-67 expression after chemotherapy remained associated with shorter PFS (p = 0.03) and OAS (p = 0.02). Paired comparison of marker expression in samples before and after induction chemotherapy of cohort 1 revealed that decreased cytoplasmic PTEN and increased phospho-mTOR expression was associated with a worse OAS (p = 0.04 and p = 0.03, respectively). CONCLUSIONS These novel data reveal a prognostic significance of expression changes of PI3K/mTOR pathway components during induction chemotherapy if confirmed in other patient cohorts and support the growing evidence to target the PI3K/mTOR pathway in the treatment of MPM.
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Yu W, He X, Ni Y, Ngeow J, Eng C. Cowden syndrome-associated germline SDHD variants alter PTEN nuclear translocation through SRC-induced PTEN oxidation. Hum Mol Genet 2014; 24:142-53. [PMID: 25149476 PMCID: PMC4262496 DOI: 10.1093/hmg/ddu425] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Germline mutations in the PTEN tumor-suppressor gene and germline variations in succinate dehydrogenase subunit D gene (SDHD-G12S, SDHD-H50R) are associated with a subset of Cowden syndrome and Cowden syndrome-like individuals (CS/CSL) and confer high risk of breast, thyroid and other cancers. However, very little is known about the underlying crosstalk between SDHD and PTEN in CS-associated thyroid cancer. Here, we show SDHD-G12S and SDHD-H50R lead to impaired PTEN function through alteration of its subcellular localization accompanied by resistance to apoptosis and induction of migration in both papillary and follicular thyroid carcinoma cell lines. Other studies have shown elevated proto-oncogene tyrosine kinase (SRC) activity in invasive thyroid cancer cells; so, we explore bosutinib, a specific inhibitor for SRC, to explore SRC as a mediator of SDH-PTEN crosstalk in this context. We show that SRC inhibition could rescue SDHD dysfunction-induced cellular phenotype and tumorigenesis only when wild-type PTEN is expressed, in thyroid cancer lines. Patient lymphoblast cells carrying either SDHD-G12S or SDHD-H50R also show increased nuclear PTEN and more oxidized PTEN after hydrogen peroxide treatment. Like in thyroid cells, bosutinib decreases oxidative PTEN in patient lymphoblast cells carrying SDHD variants, but not in patients carrying both SDHD variants and PTEN truncating mutations. In summary, our data suggest a novel mechanism whereby SDHD germline variants SDHD-G12S or SDHD-H50R induce thyroid tumorigenesis mediated by PTEN accumulation in the nucleus and may shed light on potential treatment with SRC inhibitors like bosutinib in PTEN-wild-type SDHD-variant/mutation positive CS/CSL patients and sporadic thyroid neoplasias.
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Affiliation(s)
- Wanfeng Yu
- Genomic Medicine Institute, Learner Research Institute
| | - Xin He
- Genomic Medicine Institute, Learner Research Institute
| | - Ying Ni
- Genomic Medicine Institute, Learner Research Institute CASE Comprehensive Cancer Center Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH 44116, USA and
| | - Joanne Ngeow
- Genomic Medicine Institute, Learner Research Institute Oncology Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore 169610, Singapore
| | - Charis Eng
- Genomic Medicine Institute, Learner Research Institute Taussig Cancer Institute Stanley Shalom Zielony Institute of Nursing Excellence, Cleveland Clinic, Cleveland, OH 44195, USA Department of Genetics and Genome Sciences CASE Comprehensive Cancer Center Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH 44116, USA and
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Rodríguez JA. Interplay between nuclear transport and ubiquitin/SUMO modifications in the regulation of cancer-related proteins. Semin Cancer Biol 2014; 27:11-9. [DOI: 10.1016/j.semcancer.2014.03.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 03/22/2014] [Accepted: 03/25/2014] [Indexed: 11/25/2022]
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Bao W, Florea L, Wu N, Wang Z, Banaudha K, Qian J, Houzet L, Kumar R, Kumar A. Loss of nuclear PTEN in HCV-infected human hepatocytes. Infect Agent Cancer 2014; 9:23. [PMID: 25075209 PMCID: PMC4114100 DOI: 10.1186/1750-9378-9-23] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 06/26/2014] [Indexed: 02/04/2023] Open
Abstract
Background Hepatitis C virus (HCV) infection is a major risk factor for chronic hepatitis and hepatocellular carcinoma (HCC); however, the mechanism of HCV-mediated hepatocarcinogenesis is not well understood. Insufficiency of PTEN tumor suppressor is associated with more aggressive cancers, including HCC. We asked whether viral non-coding RNA could initiate oncogenesis in HCV infected human hepatocytes. The results presented herein suggest that loss of nuclear PTEN in HCV-infected human hepatocytes results from depletion of Transportin-2, which is a direct target of viral non-coding RNA, vmr11. Methods The intracellular distribution of PTEN in HCV-infected cells was monitored by immunostaining and Western blots of nuclear and cytoplasmic proteins. Effects of PTEN depletion were examined by comparing expression arrays of uninfected cells with either HCV-infected or vmr11-transfected cells. Target genes suggested by array analyses were validated by Western blot. The influence of nuclear PTEN deficiency on virus production was determined by quantitative analysis of HCV genomic RNA in culture media of infected hepatocytes. Results Import of PTEN to the nucleus relies on the interaction of Transportin-2 and PTEN proteins; we show that depletion of Transportin-2 by HCV infection or by the introduction of vmr11 in uninfected cells results in reduced nuclear PTEN. In turn, nuclear PTEN insufficiency correlates with increased virus production and the induction of γ-H2AX, a marker of DNA double-strand breaks and genomic instability. Conclusion An HCV-derived small non-coding RNA inhibits Transportin-2 and PTEN translocation to the nucleus, suggesting a direct viral role in hepatic oncogenesis.
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Affiliation(s)
- Wenjie Bao
- Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine, 2300 Eye Street, N.W., Washington, D.C. 20037, USA
| | - Liliana Florea
- McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins University, Baltimore, MD, USA
| | - Ningbin Wu
- Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine, 2300 Eye Street, N.W., Washington, D.C. 20037, USA
| | - Zhao Wang
- Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine, 2300 Eye Street, N.W., Washington, D.C. 20037, USA
| | - Krishna Banaudha
- Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine, 2300 Eye Street, N.W., Washington, D.C. 20037, USA
| | - Jason Qian
- Current address: Metabolism Branch, NIH, Bethesda, MD, USA
| | - Laurent Houzet
- Molecular Virology Section, Laboratory of Molecular Microbiology, NIAID, NIH, Bethesda, MD, USA ; Current address: INSERM U1085-IRSET, Universite de Rennes1, Institut Federatif de Recherche 140, Rennes, France
| | - Rakesh Kumar
- Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine, 2300 Eye Street, N.W., Washington, D.C. 20037, USA
| | - Ajit Kumar
- Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine, 2300 Eye Street, N.W., Washington, D.C. 20037, USA
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Balakrishnan S, Sadasivam M, Kannan A, Panneerselvam A, Prahalathan C. Glucose modulates Pax6 expression through the JNK/p38 MAP kinase pathway in pancreatic beta-cells. Life Sci 2014; 109:1-7. [PMID: 24953606 DOI: 10.1016/j.lfs.2014.06.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 06/04/2014] [Accepted: 06/07/2014] [Indexed: 02/08/2023]
Abstract
AIM The paired and homeodomain-containing transcription factor, paired box 6 (Pax6), has shown to play pivotal roles in beta-cell function, including cell survival, insulin biosynthesis and secretion. The present study investigates the signaling events that regulate the modulation of Pax6 expression by glucose and the role of this modulation in cell survival in rat insulinoma-1E (INS-1E) cells. MAIN METHODS INS-1E cells were incubated on 1mM (low) or 25 mM (high) glucose overnight. To elucidate the signaling pathways that regulate Pax6 expression, we utilized specific inhibitors. The siRNA transfection of Pax6 into INS-1E cells was performed by electroporation. The mRNA and protein levels were determined by real-time PCR and Western blotting, respectively. KEY FINDINGS We found that the mRNA and protein levels of Pax6 were reduced by approximately 4-fold in high, compared to low, glucose-treated cells. Staurosporine, the c-Jun N-terminal kinase (JNK) inhibitor SP600125 and the p38 mitogen-activated protein kinase (p38 MAPK) inhibitor SB203580 significantly increased Pax6 levels in high glucose-treated INS-1E cells compared to their respective controls. However, neither calcium ionophore nor the extracellular signal-regulated kinase (ERK) inhibitor U0126 resulted in any alteration in Pax6 protein expression. Further, a siRNA-mediated knockdown of Pax6 significantly decreased the expression of tumor-suppressor phosphatase with tensin homology (PTEN) while increasing cell viability in low glucose-treated INS-1E cells. SIGNIFICANCE This study addresses the signaling events that regulate the glucose-dependent expression of Pax6 and the role of these events in cell survival in pancreatic beta cells.
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Affiliation(s)
| | - Mohanraj Sadasivam
- Department of Biochemistry, Bharathidasan University, Tiruchirappalli 620 024, India
| | - Arun Kannan
- Department of Biochemistry, Bharathidasan University, Tiruchirappalli 620 024, India
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Affiliation(s)
- C Bassi
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada M5G 2M9
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Wu MH, Chen YA, Chen HH, Chang KW, Chang IS, Wang LH, Hsu HL. MCT-1 expression and PTEN deficiency synergistically promote neoplastic multinucleation through the Src/p190B signaling activation. Oncogene 2014; 33:5109-20. [PMID: 24858043 PMCID: PMC4287651 DOI: 10.1038/onc.2014.125] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 03/20/2014] [Accepted: 04/03/2014] [Indexed: 12/18/2022]
Abstract
Multinucleation is associated with malignant neoplasms; however, the molecular mechanism underlying the nuclear abnormality remains unclear. Loss or mutation of PTEN promotes the development of malignant tumors. We now demonstrate that increased expression of the oncogene MCT-1 (multiple copies in T-cell malignancy 1) antagonizes PTEN gene presentation, PTEN protein stability and PTEN functional activity, thereby further promoting phosphoinositide 3 kinase/AKT signaling, survival rate and malignancies of the PTEN-deficient cells. In the PTEN-null cancer cells, MCT-1 interacts with p190B and Src in vivo, supporting that they are in proximity of the signaling complexes. MCT-1 overexpression and PTEN loss synergistically augments the Src/p190B signaling function that leads to inhibition of RhoA activity. Under such a condition, the incidence of mitotic catastrophes including spindle multipolarity and cytokinesis failure is enhanced, driving an Src/p190B/RhoA-dependent neoplastic multinucleation. Targeting MCT-1 by the short hairpin RNA markedly represses the Src/p190B function, improves nuclear structures and suppresses xenograft tumorigenicity of the PTEN-null breast cancer cells. Consistent with the oncogenic effects in vitro, clinical evidence has confirmed that MCT-1 gene stimulation is correlated with p190B gene promotion and PTEN gene suppression in human breast cancer. Accordingly, MCT-1 gene induction is recognized as a potential biomarker of breast tumor development. Abrogating MCT-1 function may be a promising stratagem for management of breast cancer involving Src hyperactivation and/or PTEN dysfunction.
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Affiliation(s)
- M-H Wu
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Taiwan, ROC
| | - Y-A Chen
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Taiwan, ROC
| | - H-H Chen
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Taiwan, ROC
| | - K-W Chang
- Institute of Population Health Science, National Health Research Institutes, Taiwan, ROC
| | - I-S Chang
- National Institute of Cancer Research and Division of Biostatistics and Bioinformatics, National Health Research Institutes, Taiwan, ROC
| | - L-H Wang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Taiwan, ROC
| | - H-L Hsu
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Taiwan, ROC
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Choi BH, Pagano M, Huang C, Dai W. Cdh1, a substrate-recruiting component of anaphase-promoting complex/cyclosome (APC/C) ubiquitin E3 ligase, specifically interacts with phosphatase and tensin homolog (PTEN) and promotes its removal from chromatin. J Biol Chem 2014; 289:17951-9. [PMID: 24811168 DOI: 10.1074/jbc.m114.559005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A pool of PTEN localizes to the nucleus. However, the exact mechanism by which nuclear PTEN is regulated remains unclear. We have recently reported that Plk1 specifically phosphorylates PTEN on Ser-380 during mitosis. Here we report that PTEN also localized to chromatin and that chromatin PTEN was removed by a proteasome-dependent process during mitotic exit. Pulldown analysis revealed that Cdh1, but not Cdc20, was significantly associated with PTEN. Cdh1 interacted with PTEN via two separate domains, and their interaction was enhanced by MG132, a proteasome inhibitor. Cdh1 negatively controlled the stability of chromatin PTEN by polyubiquitination. Phosphorylation of PTEN on Ser-380 impaired its interaction with Cdh1, thus positively regulating PTEN stability on chromatin. Significantly, the PTEN interaction with Cdh1 was phosphatase-independent, and Cdh1 knockdown via RNAi led to significant accumulation of chromatin PTEN, delaying mitotic exit. Combined, our studies identify Cdh1 as an important regulator of nuclear/chromatin PTEN during mitosis.
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Affiliation(s)
- Byeong Hyeok Choi
- From the Departments of Environmental Medicine, Biochemistry, and Molecular Pharmacology, New York University School of Medicine, Tuxedo, New York 10987
| | - Michele Pagano
- the Department of Pathology, New York University Cancer Institute, New York University School of Medicine, New York, New York 10016, and the Howard Hughes Medical Institute, New York University School of Medicine, New York, New York 10016
| | - Chaunshu Huang
- From the Departments of Environmental Medicine, Biochemistry, and Molecular Pharmacology, New York University School of Medicine, Tuxedo, New York 10987
| | - Wei Dai
- From the Departments of Environmental Medicine, Biochemistry, and Molecular Pharmacology, New York University School of Medicine, Tuxedo, New York 10987,
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NAKANISHI ATSUKO, KITAGISHI YASUKO, OGURA YASUNORI, MATSUDA SATORU. The tumor suppressor PTEN interacts with p53 in hereditary cancer. Int J Oncol 2014; 44:1813-9. [DOI: 10.3892/ijo.2014.2377] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 03/26/2014] [Indexed: 11/05/2022] Open
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Kreis P, Leondaritis G, Lieberam I, Eickholt BJ. Subcellular targeting and dynamic regulation of PTEN: implications for neuronal cells and neurological disorders. Front Mol Neurosci 2014; 7:23. [PMID: 24744697 PMCID: PMC3978343 DOI: 10.3389/fnmol.2014.00023] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 03/12/2014] [Indexed: 01/13/2023] Open
Abstract
PTEN is a lipid and protein phosphatase that regulates a diverse range of cellular mechanisms. PTEN is mainly present in the cytosol and transiently associates with the plasma membrane to dephosphorylate PI(3,4,5)P3, thereby antagonizing the PI3-Kinase signaling pathway. Recently, PTEN has been shown to associate also with organelles such as the endoplasmic reticulum (ER), the mitochondria, or the nucleus, and to be secreted outside of the cell. In addition, PTEN dynamically localizes to specialized sub-cellular compartments such as the neuronal growth cone or dendritic spines. The diverse localizations of PTEN imply a tight temporal and spatial regulation, orchestrated by mechanisms such as posttranslational modifications, formation of distinct protein–protein interactions, or the activation/recruitment of PTEN downstream of external cues. The regulation of PTEN function is thus not only important at the enzymatic activity level, but is also associated to its spatial distribution. In this review we will summarize (i) recent findings that highlight mechanisms controlling PTEN movement and sub-cellular localization, and (ii) current understanding of how PTEN localization is achieved by mechanisms controlling posttranslational modification, by association with binding partners and by PTEN structural or activity requirements. Finally, we will discuss the possible roles of compartmentalized PTEN in developing and mature neurons in health and disease.
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Affiliation(s)
- Patricia Kreis
- MRC Centre for Developmental Neurobiology, King's College London London, UK
| | - George Leondaritis
- MRC Centre for Developmental Neurobiology, King's College London London, UK ; Institute of Biochemistry, Charité - Universitätsmedizin Berlin Berlin, Germany
| | - Ivo Lieberam
- MRC Centre for Developmental Neurobiology, King's College London London, UK
| | - Britta J Eickholt
- MRC Centre for Developmental Neurobiology, King's College London London, UK ; Institute of Biochemistry, Charité - Universitätsmedizin Berlin Berlin, Germany
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Li Y, Wang H. [Research progress of the relationship between tumor suppressor gene
PTEN and non-small cell lung cancer]. ZHONGGUO FEI AI ZA ZHI = CHINESE JOURNAL OF LUNG CANCER 2014; 17:260-4. [PMID: 24667265 PMCID: PMC6019367 DOI: 10.3779/j.issn.1009-3419.2014.03.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Yanan Li
- Hebei United University, Tangshan 063009, China
| | - Hongwu Wang
- Department of Medical Oncology, China Meitan General Hospital,
Beijing 100028, China
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Wu Y, Zhou H, Wu K, Lee S, Li R, Liu X. PTEN phosphorylation and nuclear export mediate free fatty acid-induced oxidative stress. Antioxid Redox Signal 2014; 20:1382-95. [PMID: 24063548 PMCID: PMC3936505 DOI: 10.1089/ars.2013.5498] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
AIM Oxidative stress induced by free fatty acids (FFA) contributes to metabolic syndrome-associated development of cardiovascular diseases, yet molecular mechanisms remain poorly understood. This study aimed at establishing whether phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and its subcellular location play a role in FFA-induced endothelial oxidative stress. RESULTS Exposing human endothelial cells (ECs) with FFA activated mammalian target of rapamycin (mTOR)/S6K pathway, and upon activation, S6K directly phosphorylated PTEN at S380. Phosphorylation of PTEN increased its interaction with its deubiquitinase USP7 in the nucleus, leading to PTEN deubiquitination and nuclear export. The reduction of PTEN in the nucleus, in turn, decreased p53 acetylation and transcription, reduced the expression of the p53 target gene glutathione peroxidase-1 (GPX1), resulting in reactive oxygen species (ROS) accumulation and endothelial damage. Finally, C57BL/6J mice fed with high-fat atherogenic diet (HFAD) showed PTEN nuclear export, decreased p53 and GPX1 protein expressions, elevated levels of ROS, and significant lesions in aortas. Importantly, inhibition of mTOR or S6K effectively blocked these effects, suggesting that mTOR/S6K pathway mediates HFAD-induced oxidative stress and vascular damage via PTEN/p53/GPX1 inhibition in vivo. INNOVATION Our study demonstrated for the first time that S6K directly phosphorylated PTEN at S380 under high FFA conditions, and this phosphorylation mediated FFA-induced endothelial oxidative stress. Furthermore, we showed that S380 phosphorylation affected PTEN monoubiquitination and nuclear localization, providing the first example of coordinated regulation of PTEN nuclear localization via phosphorylation and ubiquitination. CONCLUSION Our studies provide a novel mechanism by which hyperlipidemia causes vascular oxidative damage through the phosphorylation of PTEN, blocking of PTEN nuclear function, and inhibition of p53/GPX1 activity.
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Affiliation(s)
- Yong Wu
- 1 Department of Biochemistry, University of California , Riverside, California
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Hühns M, Salem T, Schneider B, Krohn M, Linnebacher M, Prall F. PTEN mutation, loss of heterozygosity, promoter methylation and expression in colorectal carcinoma: two hits on the gene? Oncol Rep 2014; 31:2236-44. [PMID: 24647592 DOI: 10.3892/or.2014.3097] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 02/03/2014] [Indexed: 11/05/2022] Open
Abstract
The phosphatase and tensin homologue (PTEN) gene is considered to be a tumour-suppressor gene in various types of cancer, colorectal carcinoma among them. According to the 'two-hit' tumour-suppressor gene concept, inactivation occurs by any combination of the following three pathogenetic processes: mutation, loss of one allele [i.e. loss of heterozygosity (LOH)] or promoter methylation. To determine the frequencies of PTEN tumour-suppressor gene features in colorectal carcinoma, we used DNA from colorectal carcinoma xenografts/primary tumour cell lines (N=22) or neoplastic glands isolated by laser-capture microdissection (N=20). Sequencing exons 1-9 of the gene revealed a total of 8 somatic mutations in 5 tumours (3 with high-degree microsatellite instability). In 1 tumour, a truncating mutation of one allele was combined with two missense mutations of the other allele. Polymorphic microsatellite marker analyses (D10S5412, D10S579 and D10S1765) showed complete loss of one allele (i.e. LOH sensu stricto) in 3 tumours, but combined LOH and mutation was found only once. Promoter methylation, tested by MethyLight technology, was found in only 1 of the tumours, not combined with mutation or LOH. In contrast, by immunohistochemistry (mAb 6H2.1), reduction or even loss of PTEN expression was found in 18 tumours. Taken together, PTEN downregulation is a fairly frequent event in colorectal carcinoma, but this apparently is not usually caused by two hits on the gene.
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Affiliation(s)
- Maja Hühns
- Institute of Pathology, Rostock University, D-18055 Rostock, Germany
| | - Tareq Salem
- Institute of Pathology, Rostock University, D-18055 Rostock, Germany
| | - Björn Schneider
- Institute of Pathology, Rostock University, D-18055 Rostock, Germany
| | - Mathias Krohn
- Department of Surgery, Rostock University, D-18055 Rostock, Germany
| | | | - Friedrich Prall
- Institute of Pathology, Rostock University, D-18055 Rostock, Germany
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A novel PTEN/mutant p53/c-Myc/Bcl-XL axis mediates context-dependent oncogenic effects of PTEN with implications for cancer prognosis and therapy. Neoplasia 2014; 15:952-65. [PMID: 23908595 DOI: 10.1593/neo.13376] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 06/05/2013] [Accepted: 06/10/2013] [Indexed: 12/21/2022] Open
Abstract
Phosphatase and tensin homolog located on chromosome 10 (PTEN) is one of the most frequently mutated tumor suppressors in human cancer including in glioblastoma. Here, we show that PTEN exerts unconventional oncogenic effects in glioblastoma through a novel PTEN/mutant p53/c-Myc/Bcl-XL molecular and functional axis. Using a wide array of molecular, genetic, and functional approaches, we demonstrate that PTEN enhances a transcriptional complex containing gain-of-function mutant p53, CBP, and NFY in human glioblastoma cells and tumor tissues. The mutant p53/CBP/NFY complex transcriptionally activates the oncogenes c-Myc and Bcl-XL, leading to increased cell proliferation, survival, invasion, and clonogenicity. Disruption of the mutant p53/c-Myc/Bcl-XL axis or mutant p53/CBP/NFY complex reverses the transcriptional and oncogenic effects of PTEN and unmasks its tumor-suppressive function. Consistent with these data, we find that PTEN expression is associated with worse patient survival than PTEN loss in tumors harboring mutant p53 and that a small molecule modulator of p53 exerts greater antitumor effects in PTEN-expressing cancer cells. Altogether, our study describes a new signaling pathway that mediates context-dependent oncogenic/tumor-suppressive role of PTEN. The data also indicate that the combined mutational status of PTEN and p53 influences cancer prognosis and anticancer therapies that target PTEN and p53.
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127
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Abbotts R, Thompson N, Madhusudan S. DNA repair in cancer: emerging targets for personalized therapy. Cancer Manag Res 2014; 6:77-92. [PMID: 24600246 PMCID: PMC3933425 DOI: 10.2147/cmar.s50497] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Genomic deoxyribonucleic acid (DNA) is under constant threat from endogenous and exogenous DNA damaging agents. Mammalian cells have evolved highly conserved DNA repair machinery to process DNA damage and maintain genomic integrity. Impaired DNA repair is a major driver for carcinogenesis and could promote aggressive cancer biology. Interestingly, in established tumors, DNA repair activity is required to counteract oxidative DNA damage that is prevalent in the tumor microenvironment. Emerging clinical data provide compelling evidence that overexpression of DNA repair factors may have prognostic and predictive significance in patients. More recently, DNA repair inhibition has emerged as a promising target for anticancer therapy. Synthetic lethality exploits intergene relationships where the loss of function of either of two related genes is nonlethal, but loss of both causes cell death. Exploiting this approach by targeting DNA repair has emerged as a promising strategy for personalized cancer therapy. In the current review, we focus on recent advances with a particular focus on synthetic lethality targeting in cancer.
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Affiliation(s)
- Rachel Abbotts
- University of Nottingham, Academic Unit of Oncology, Division of Oncology, School of Medicine, Nottingham University Hospitals, City Hospital Campus, Nottingham, UK
| | - Nicola Thompson
- University of Nottingham, Academic Unit of Oncology, Division of Oncology, School of Medicine, Nottingham University Hospitals, City Hospital Campus, Nottingham, UK
| | - Srinivasan Madhusudan
- University of Nottingham, Academic Unit of Oncology, Division of Oncology, School of Medicine, Nottingham University Hospitals, City Hospital Campus, Nottingham, UK
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Yang KT, Bayan JA, Zeng N, Aggarwal R, He L, Peng Z, Kassa A, Kim M, Luo Z, Shi Z, Medina V, Boddupally K, Stiles BL. Adult-onset deletion of Pten increases islet mass and beta cell proliferation in mice. Diabetologia 2014; 57:352-61. [PMID: 24162585 PMCID: PMC3918745 DOI: 10.1007/s00125-013-3085-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 09/27/2013] [Indexed: 12/31/2022]
Abstract
AIMS/HYPOTHESIS Adult beta cells have a diminished ability to proliferate. Phosphatase and tensin homologue (PTEN) is a lipid phosphatase that antagonises the function of the mitogenic phosphatidylinositol 3-kinase (PI3K) pathway. The objective of this study was to understand the role of PTEN and PI3K signalling in the maintenance of beta cells postnatally. METHODS We developed a Pten (lox/lox); Rosa26 (lacZ); RIP-CreER (+) model that permitted us to induce Pten deletion by treatment with tamoxifen in mature animals. We evaluated islet mass and function as well as beta cell proliferation in 3- and 12-month-old mice treated with tamoxifen (Pten deleted) vs mice treated with vehicle (Pten control). RESULTS Deletion of Pten in juvenile (3-month-old) beta cells significantly induced their proliferation and increased islet mass. The expansion of islet mass occurred concomitantly with the enhanced ability of the Pten-deleted mice to maintain euglycaemia in response to streptozotocin treatment. In older mice (>12 months of age), deletion of Pten similarly increased islet mass and beta cell proliferation. This novel finding suggests that PTEN-regulated mechanisms may override the age-onset diminished ability of beta cells to respond to mitogenic stimulation. We also found that proteins regulating G1/S cell-cycle transition, such as cyclin D1, cyclin D2, p27 and p16, were altered when PTEN was lost, suggesting that they may play a role in PTEN/PI3K-regulated beta cell proliferation in adult tissue. CONCLUSIONS/INTERPRETATION The signals regulated by the PTEN/PI3K pathway are important for postnatal maintenance of beta cells and regulation of their proliferation in adult tissues.
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Affiliation(s)
- Kai-Ting Yang
- Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, CA, USA
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Chappell MC, Marshall AC, Alzayadneh EM, Shaltout HA, Diz DI. Update on the Angiotensin converting enzyme 2-Angiotensin (1-7)-MAS receptor axis: fetal programing, sex differences, and intracellular pathways. Front Endocrinol (Lausanne) 2014; 4:201. [PMID: 24409169 PMCID: PMC3886117 DOI: 10.3389/fendo.2013.00201] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 12/18/2013] [Indexed: 12/12/2022] Open
Abstract
The renin-angiotensin-system (RAS) constitutes an important hormonal system in the physiological regulation of blood pressure. Indeed, dysregulation of the RAS may lead to the development of cardiovascular pathologies including kidney injury. Moreover, the blockade of this system by the inhibition of angiotensin converting enzyme (ACE) or antagonism of the angiotensin type 1 receptor (AT1R) constitutes an effective therapeutic regimen. It is now apparent with the identification of multiple components of the RAS that the system is comprised of different angiotensin peptides with diverse biological actions mediated by distinct receptor subtypes. The classic RAS can be defined as the ACE-Ang II-AT1R axis that promotes vasoconstriction, sodium retention, and other mechanisms to maintain blood pressure, as well as increased oxidative stress, fibrosis, cellular growth, and inflammation in pathological conditions. In contrast, the non-classical RAS composed of the ACE2-Ang-(1-7)-Mas receptor axis generally opposes the actions of a stimulated Ang II-AT1R axis through an increase in nitric oxide and prostaglandins and mediates vasodilation, natriuresis, diuresis, and oxidative stress. Thus, a reduced tone of the Ang-(1-7) system may contribute to these pathologies as well. Moreover, the non-classical RAS components may contribute to the effects of therapeutic blockade of the classical system to reduce blood pressure and attenuate various indices of renal injury. The review considers recent studies on the ACE2-Ang-(1-7)-Mas receptor axis regarding the precursor for Ang-(1-7), the intracellular expression and sex differences of this system, as well as an emerging role of the Ang1-(1-7) pathway in fetal programing events and cardiovascular dysfunction.
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Affiliation(s)
- Mark C. Chappell
- The Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Allyson C. Marshall
- The Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Ebaa M. Alzayadneh
- The Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Hossam A. Shaltout
- The Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
- Department of Pharmacology and Toxicology, School of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Debra I. Diz
- The Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA
- *Correspondence: Debra I. Diz, The Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157-1032, USA e-mail:
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An H, Krist DT, Statsyuk AV. Crosstalk between kinases and Nedd4 family ubiquitin ligases. ACTA ACUST UNITED AC 2014; 10:1643-57. [DOI: 10.1039/c3mb70572b] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Understanding the interplay between kinase and E3 ligase signaling pathways will allow better understanding of therapeutically relevant pathways and the design of small molecule therapeutics targeting these pathways.
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Affiliation(s)
- Heeseon An
- Department of Chemistry
- Northwestern University
- Evanston, USA
| | - David T. Krist
- Department of Chemistry
- Northwestern University
- Evanston, USA
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Dillon LM, Miller TW. Therapeutic targeting of cancers with loss of PTEN function. Curr Drug Targets 2014; 15:65-79. [PMID: 24387334 PMCID: PMC4310752 DOI: 10.2174/1389450114666140106100909] [Citation(s) in RCA: 170] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 09/30/2013] [Accepted: 11/02/2013] [Indexed: 02/08/2023]
Abstract
Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is one of the most frequently disrupted tumor suppressors in cancer. The lipid phosphatase activity of PTEN antagonizes the phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR pathway to repress tumor cell growth and survival. In the nucleus, PTEN promotes chromosome stability and DNA repair. Consequently, loss of PTEN function increases genomic instability. PTEN deficiency is caused by inherited germline mutations, somatic mutations, epigenetic and transcriptional silencing, post-translational modifications, and protein-protein interactions. Given the high frequency of PTEN deficiency across cancer subtypes, therapeutic approaches that exploit PTEN loss-of-function could provide effective treatment strategies. Herein, we discuss therapeutic strategies aimed at cancers with loss of PTEN function, and the challenges involved in treating patients afflicted with such cancers. We review preclinical and clinical findings, and highlight novel strategies under development to target PTENdeficient cancers.
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Affiliation(s)
| | - Todd W Miller
- Dartmouth-Hitchcock Medical Center, One Medical Center Dr. HB-7936, Lebanon, NH 03756, USA.
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Das R, Bhattacharya K, Sarkar S, Samanta SK, Pal BC, Mandal C. Mahanine synergistically enhances cytotoxicity of 5-fluorouracil through ROS-mediated activation of PTEN and p53/p73 in colon carcinoma. Apoptosis 2014; 19:149-64. [PMID: 24052409 DOI: 10.1007/s10495-013-0907-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
5-Fluorouracil (5-FU) alone or in combination with other drugs is the main basis of chemotherapeutic treatment in colorectal cancer although patients with microsatellite instability generally show resistance to 5-FU treatment. The present investigation is focussed on the mechanistic insight of a pure herbal carbazole alkaloid, mahanine, as a single or in combination with 5-FU in colon cancer. We demonstrated that mahanine-induced apoptosis involved reactive oxygen species (ROS)-mediated nuclear accumulation of PTEN and its interaction with p53/p73. Mahanine and 5-FU in combination exerted synergistic inhibitory effect on cell viability. This combination also enhanced ROS production, increased tumour suppressor proteins and suppressed chemo-migration. Taken together, our results revealed that mahanine can be a potential chemotherapeutic agent with efficacy to reduce the concentration of toxic 5-FU in colon cancer.
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Affiliation(s)
- Ranjita Das
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata, 700032, India
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Correia NC, Gírio A, Antunes I, Martins LR, Barata JT. The multiple layers of non-genetic regulation of PTEN tumour suppressor activity. Eur J Cancer 2014; 50:216-25. [DOI: 10.1016/j.ejca.2013.08.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/29/2013] [Accepted: 08/20/2013] [Indexed: 12/19/2022]
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Wells PG, Miller-Pinsler L, Shapiro AM. Impact of Oxidative Stress on Development. OXIDATIVE STRESS IN APPLIED BASIC RESEARCH AND CLINICAL PRACTICE 2014. [DOI: 10.1007/978-1-4939-1405-0_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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135
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PTEN, Longevity and Age-Related Diseases. Biomedicines 2013; 1:17-48. [PMID: 28548055 PMCID: PMC5423463 DOI: 10.3390/biomedicines1010017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 11/26/2013] [Accepted: 12/09/2013] [Indexed: 02/08/2023] Open
Abstract
Since the discovery of PTEN, this protein has been shown to be an effective suppressor of cancer and a contributor to longevity. This report will review, in depth, the associations between PTEN and other molecules, its mutations and regulations in order to present how PTEN can be used to increase longevity. This report will collect recent research of PTEN and use this to discuss PTEN’s role in caloric restriction, antioxidative defense of DNA-damage and the role it plays in suppressing tumors. The report will also discuss that variety of ways that PTEN can be compromised, through mutations, complete loss of alleles and its main antagonist, the PI3K/AKT pathway.
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Goh CP, Putz U, Howitt J, Low LH, Gunnersen J, Bye N, Morganti-Kossmann C, Tan SS. Nuclear trafficking of Pten after brain injury leads to neuron survival not death. Exp Neurol 2013; 252:37-46. [PMID: 24275527 DOI: 10.1016/j.expneurol.2013.11.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/29/2013] [Accepted: 11/15/2013] [Indexed: 10/26/2022]
Abstract
There is controversy whether accumulation of the tumor suppressor PTEN protein in the cell nucleus under stress conditions such as trauma and stroke causes cell death. A number of in vitro studies have reported enhanced apoptosis in neurons possessing nuclear PTEN, with the interpretation that its nuclear phosphatase activity leads to reduction of the survival protein phospho-Akt. However, there have been no in vivo studies to show that nuclear PTEN in neurons under stress is detrimental. Using a mouse model of injury, we demonstrate here that brain trauma altered the nucleo-cytoplasmic distribution of Pten, resulting in increased nuclear Pten but only in surviving neurons near the lesion. This event was driven by Ndfip1, an adaptor and activator of protein ubiquitination by Nedd4 E3 ligases. Neurons next to the lesion with nuclear PTEN were invariably negative for TUNEL, a marker for cell death. These neurons also showed increased Ndfip1 which we previously showed to be associated with neuron survival. Biochemical assays revealed that overall levels of Pten in the affected cortex were unchanged after trauma, suggesting that Pten abundance globally had not increased but rather Pten subcellular location in affected neurons had changed. Following experimental injury, the number of neurons with nuclear Pten was reduced in heterozygous mice (Ndfip1(+/-)) although lesion volumes were increased. We conclude that nuclear trafficking of Pten following injury leads to neuron survival not death.
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Affiliation(s)
- Choo-Peng Goh
- Brain Development and Regeneration Laboratory, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Ulrich Putz
- Brain Development and Regeneration Laboratory, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Jason Howitt
- Brain Development and Regeneration Laboratory, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Ley-Hian Low
- Brain Development and Regeneration Laboratory, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Jenny Gunnersen
- Brain Development and Regeneration Laboratory, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Nicole Bye
- National Trauma Research Institute, Alfred Hospital, Monash University, Australia
| | | | - Seong-Seng Tan
- Brain Development and Regeneration Laboratory, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia.
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137
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Hong SW, Moon JH, Kim JS, Shin JS, Jung KA, Lee WK, Jeong SY, Hwang JJ, Lee SJ, Suh YA, Kim I, Nam KY, Han S, Kim JE, Kim KP, Hong YS, Lee JL, Lee WJ, Choi EK, Lee JS, Jin DH, Kim TW. p34 is a novel regulator of the oncogenic behavior of NEDD4-1 and PTEN. Cell Death Differ 2013; 21:146-60. [PMID: 24141722 DOI: 10.1038/cdd.2013.141] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 07/04/2013] [Accepted: 07/31/2013] [Indexed: 11/09/2022] Open
Abstract
PTEN is one of the most frequently mutated or deleted tumor suppressors in human cancers. NEDD4-1 was recently identified as the E3 ubiquitin ligase for PTEN; however, a number of important questions remain regarding the role of ubiquitination in regulating PTEN function and the mechanisms by which PTEN ubiquitination is regulated. In the present study, we demonstrated that p34, which was identified as a binding partner of NEDD4-1, controls PTEN ubiquitination by regulating NEDD4-1 protein stability. p34 interacts with the WW1 domain of NEDD4-1, an interaction that enhances NEDD4-1 stability. Expression of p34 promotes PTEN poly-ubiquitination, leading to PTEN protein degradation, whereas p34 knockdown results in PTEN mono-ubiquitination. Notably, an inverse correlation between PTEN and p34/NEDD4-1 levels was confirmed in tumor samples from colon cancer patients. Thus, p34 acts as a key regulator of the oncogenic behavior of NEDD4-1 and PTEN.
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Affiliation(s)
- S-W Hong
- 1] Innovative Cancer Research, Asan Medical Center, Asan Institute for Life Science, University of Ulsan College of Medicine, Seoul, Republic of Korea [2] Department of Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
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138
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Choi BH, Chen Y, Dai W. Chromatin PTEN is involved in DNA damage response partly through regulating Rad52 sumoylation. Cell Cycle 2013; 12:3442-7. [PMID: 24047694 DOI: 10.4161/cc.26465] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A pool of PTEN localizes to the nucleus. However, the exact mechanism of action of nuclear PTEN remains poorly understood. We have investigated PTEN's role during DNA damage response. Here we report that PTEN undergoes chromatin translocation after DNA damage, and that its translocation is closely associated with its phosphorylation on S366/T370 but not on S380. Deletional analysis reveals that the C2 domain of PTEN is responsible for its nuclear translocation after exposure to genotoxin. Both casein kinase 2 and GSK3β are involved in the phosphorylation of the S366/T370 epitope, as well as PTEN's association with chromatin after DNA damage. Significantly, PTEN specifically interacts with Rad52 and colocalizes with Rad52, as well as γH2AX, after genotoxic stress. Moreover, PTEN is involved in regulating Rad52 sumoylation. Combined, our studies strongly suggest that nuclear/chromatin PTEN mediates DNA damage repair through interacting with and modulating the activity of Rad52.
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Affiliation(s)
- Byeong Hyeok Choi
- Departments of Environmental Medicine, Biochemistry, and Molecular Pharmacology; New York University School of Medicine; Tuxedo, NY USA
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139
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Iwata J, Suzuki A, Pelikan RC, Ho TV, Sanchez-Lara PA, Chai Y. Modulation of lipid metabolic defects rescues cleft palate in Tgfbr2 mutant mice. Hum Mol Genet 2013; 23:182-93. [PMID: 23975680 DOI: 10.1093/hmg/ddt410] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mutations in transforming growth factor beta (TGFβ) receptor type II (TGFBR2) cause Loeys-Dietz syndrome, characterized by craniofacial and cardiovascular abnormalities. Mice with a deletion of Tgfbr2 in cranial neural crest cells (Tgfbr2(fl/fl);Wnt1-Cre mice) develop cleft palate as the result of abnormal TGFβ signaling activation. However, little is known about metabolic processes downstream of TGFβ signaling during palatogenesis. Here, we show that Tgfbr2 mutant palatal mesenchymal cells spontaneously accumulate lipid droplets, resulting from reduced lipolysis activity. Tgfbr2 mutant palatal mesenchymal cells failed to respond to the cell proliferation stimulator sonic hedgehog, derived from the palatal epithelium. Treatment with p38 mitogen-activated protein kinase (MAPK) inhibitor or telmisartan, a modulator of p38 MAPK activation and lipid metabolism, blocked abnormal TGFβ-mediated p38 MAPK activation, restoring lipid metabolism and cell proliferation activity both in vitro and in vivo. Our results highlight the influence of alternative TGFβ signaling on lipid metabolic activities, as well as how lipid metabolic defects can affect cell proliferation and adversely impact palatogenesis. This discovery has broader implications for the understanding of metabolic defects and potential prevention of congenital birth defects.
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Affiliation(s)
- Junichi Iwata
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry and
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140
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Kreis P, Hendricusdottir R, Kay L, Papageorgiou IE, van Diepen M, Mack T, Ryves J, Harwood A, Leslie NR, Kann O, Parsons M, Eickholt BJ. Phosphorylation of the actin binding protein Drebrin at S647 is regulated by neuronal activity and PTEN. PLoS One 2013; 8:e71957. [PMID: 23940795 PMCID: PMC3733845 DOI: 10.1371/journal.pone.0071957] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 07/04/2013] [Indexed: 01/24/2023] Open
Abstract
Defects in actin dynamics affect activity-dependent modulation of synaptic transmission and neuronal plasticity, and can cause cognitive impairment. A salient candidate actin-binding protein linking synaptic dysfunction to cognitive deficits is Drebrin (DBN). However, the specific mode of how DBN is regulated at the central synapse is largely unknown. In this study we identify and characterize the interaction of the PTEN tumor suppressor with DBN. Our results demonstrate that PTEN binds DBN and that this interaction results in the dephosphorylation of a site present in the DBN C-terminus--serine 647. PTEN and pS647-DBN segregate into distinct and complimentary compartments in neurons, supporting the idea that PTEN negatively regulates DBN phosphorylation at this site. We further demonstrate that neuronal activity increases phosphorylation of DBN at S647 in hippocampal neurons in vitro and in ex vivo hippocampus slices exhibiting seizure activity, potentially by inducing rapid dissociation of the PTEN:DBN complex. Our results identify a novel mechanism by which PTEN is required to maintain DBN phosphorylation at dynamic range and signifies an unusual regulation of an actin-binding protein linked to cognitive decline and degenerative conditions at the CNS synapse.
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Affiliation(s)
- Patricia Kreis
- MRC Centre for Developmental Neurobiology, King’s College London, London, United Kingdom
| | - Rita Hendricusdottir
- MRC Centre for Developmental Neurobiology, King’s College London, London, United Kingdom
| | - Louise Kay
- MRC Centre for Developmental Neurobiology, King’s College London, London, United Kingdom
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Ismini E. Papageorgiou
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Michiel van Diepen
- MRC Centre for Developmental Neurobiology, King’s College London, London, United Kingdom
- Novartis Pharmaceuticals UK Limited, Horsham, United Kingdom
| | - Till Mack
- Cluster of Excellence NeuroCure and Institute of Biochemistry, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jonny Ryves
- Cardiff School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Adrian Harwood
- Cardiff School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | | | - Oliver Kann
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Maddy Parsons
- The Randall Division of Cell and Molecular Biophysics, King’s College London, London, United Kingdom
| | - Britta J. Eickholt
- MRC Centre for Developmental Neurobiology, King’s College London, London, United Kingdom
- Cluster of Excellence NeuroCure and Institute of Biochemistry, Charité - Universitätsmedizin Berlin, Berlin, Germany
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141
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Bassi C, Ho J, Srikumar T, Dowling RJO, Gorrini C, Miller SJ, Mak TW, Neel BG, Raught B, Stambolic V. Nuclear PTEN controls DNA repair and sensitivity to genotoxic stress. Science 2013; 341:395-9. [PMID: 23888040 PMCID: PMC5087104 DOI: 10.1126/science.1236188] [Citation(s) in RCA: 320] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Loss of function of the phosphatase and tensin homolog deleted on chromosome 10 (PTEN) tumor suppressor gene is associated with many human cancers. In the cytoplasm, PTEN antagonizes the phosphatidylinositol 3-kinase (PI3K) signaling pathway. PTEN also accumulates in the nucleus, where its function remains poorly understood. We demonstrate that SUMOylation (SUMO, small ubiquitin-like modifier) of PTEN controls its nuclear localization. In cells exposed to genotoxic stress, SUMO-PTEN was rapidly excluded from the nucleus dependent on the protein kinase ataxia telangiectasia mutated (ATM). Cells lacking nuclear PTEN were hypersensitive to DNA damage, whereas PTEN-deficient cells were susceptible to killing by a combination of genotoxic stress and a small-molecule PI3K inhibitor both in vitro and in vivo. Our findings may have implications for individualized therapy for patients with PTEN-deficient tumors.
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Affiliation(s)
- C Bassi
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, M5G 2M9, Canada
| | - J Ho
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, M5G 2M9, Canada
| | - T Srikumar
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, M5G 2M9, Canada
| | - RJO Dowling
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, M5G 2M9, Canada
| | - C Gorrini
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, M5G 2M9, Canada
- Campbell Family Institute for Breast Cancer Research, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, M5G 2C1 Canada
| | - SJ Miller
- Division of Hematology/Oncology and Cancer Biology Program, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115
| | - TW Mak
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, M5G 2M9, Canada
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, M5G 2M9, Canada
- Campbell Family Institute for Breast Cancer Research, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, M5G 2C1 Canada
| | - BG Neel
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, M5G 2M9, Canada
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, M5G 2M9, Canada
- Division of Hematology/Oncology and Cancer Biology Program, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115
| | - B Raught
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, M5G 2M9, Canada
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, M5G 2M9, Canada
| | - V Stambolic
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, M5G 2M9, Canada
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, M5G 2M9, Canada
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142
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Vitucci M, Karpinich NO, Bash RE, Werneke AM, Schmid RS, White KK, McNeill RS, Huff B, Wang S, Van Dyke T, Miller CR. Cooperativity between MAPK and PI3K signaling activation is required for glioblastoma pathogenesis. Neuro Oncol 2013; 15:1317-29. [PMID: 23814263 DOI: 10.1093/neuonc/not084] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Glioblastoma (GBM) genomes feature recurrent genetic alterations that dysregulate core intracellular signaling pathways, including the G1/S cell cycle checkpoint and the MAPK and PI3K effector arms of receptor tyrosine kinase (RTK) signaling. Elucidation of the phenotypic consequences of activated RTK effectors is required for the design of effective therapeutic and diagnostic strategies. METHODS Genetically defined, G1/S checkpoint-defective cortical murine astrocytes with constitutively active Kras and/or Pten deletion mutations were used to systematically investigate the individual and combined roles of these 2 RTK signaling effectors in phenotypic hallmarks of glioblastoma pathogenesis, including growth, migration, and invasion in vitro. A novel syngeneic orthotopic allograft model system was used to examine in vivo tumorigenesis. RESULTS Constitutively active Kras and/or Pten deletion mutations activated both MAPK and PI3K signaling. Their combination led to maximal growth, migration, and invasion of G1/S-defective astrocytes in vitro and produced progenitor-like transcriptomal profiles that mimic human proneural GBM. Activation of both RTK effector arms was required for in vivo tumorigenesis and produced highly invasive, proneural-like GBM. CONCLUSIONS These results suggest that cortical astrocytes can be transformed into GBM and that combined dysregulation of MAPK and PI3K signaling revert G1/S-defective astrocytes to a primitive gene expression state. This genetically-defined, immunocompetent model of proneural GBM will be useful for preclinical development of MAPK/PI3K-targeted, subtype-specific therapies.
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Affiliation(s)
- Mark Vitucci
- Corresponding Author: C. Ryan Miller, MD, PhD, University of North Carolina School of Medicine, 6109B Neurosciences Research Building, Campus Box 7250, Chapel Hill, NC 27599-7250.
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143
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Song M, Chen D, Lu B, Wang C, Zhang J, Huang L, Wang X, Timmons CL, Hu J, Liu B, Wu X, Wang L, Wang J, Liu H. PTEN loss increases PD-L1 protein expression and affects the correlation between PD-L1 expression and clinical parameters in colorectal cancer. PLoS One 2013; 8:e65821. [PMID: 23785454 PMCID: PMC3681867 DOI: 10.1371/journal.pone.0065821] [Citation(s) in RCA: 204] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 04/28/2013] [Indexed: 12/21/2022] Open
Abstract
Background Programmed death ligand-1 (PD-L1) has been identified as a factor associated with poor prognosis in a range of cancers, and was reported to be mainly induced by PTEN loss in gliomas. However, the clinical effect of PD-L1 and its regulation by PTEN has not yet been determined in colorectal cancer (CRC). In the present study, we verified the regulation of PTEN on PD-L1 and further determined the effect of PTEN on the correlation between PD-L1 expression and clinical parameters in CRC. Methods/Results RNA interference approach was used to down-regulate PTEN expression in SW480, SW620 and HCT116 cells. It was showed that PD-L1 protein, but not mRNA, was significantly increased in cells transfected with siRNA PTEN compared with the negative control. Moreover, the capacity of PTEN to regulate PD-L1 expression was not obviously affected by IFN-γ, the main inducer of PD-L1. Tissue microarray immunohistochemistry was used to detect PD-L1 and PTEN in 404 CRC patient samples. Overexpression of PD-L1 was significantly correlated with distant metastasis (P<0.001), TNM stage (P<0.01), metastatic progression (P<0.01) and PTEN expression (P<0.001). Univariate analysis revealed that patients with high PD-L1 expression had a poor overall survival (P<0.001). However, multivariate analysis did not support PD-L1 as an independent prognostic factor (P = 0.548). Univariate (P<0.001) and multivariate survival (P<0.001) analysis of 310 located CRC patients revealed that high level of PD-L1 expression was associated with increased risks of metastatic progression. Furthermore, the clinical effect of PD-L1 on CRC was not statistically significant in a subset of 39 patients with no PTEN expression (distant metastasis: P = 0.102; TNM stage: P = 0.634, overall survival: P = 0.482). Conclusions PD-L1 can be used to identify CRC patients with high risk of metastasis and poor prognosis. This clinical manifestation may be partly associated with PTEN expression.
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Affiliation(s)
- Minmin Song
- Institute of Gastroenterology and the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Human Virology, Sun Yat-sen University, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China
| | - Defeng Chen
- Institute of Gastroenterology and the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Biyan Lu
- Institute of Gastroenterology and the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Human Virology, Sun Yat-sen University, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China
- Dongguan Health School, Dongguan, Guangdong, China
| | - Chenliang Wang
- Institute of Gastroenterology and the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Human Virology, Sun Yat-sen University, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Junxiao Zhang
- Institute of Gastroenterology and the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Human Virology, Sun Yat-sen University, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China
| | - Lanlan Huang
- Institute of Gastroenterology and the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Human Virology, Sun Yat-sen University, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China
| | - Xiaoyan Wang
- Institute of Gastroenterology and the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Human Virology, Sun Yat-sen University, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China
| | - Christine L. Timmons
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Jun Hu
- Institute of Gastroenterology and the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Bindong Liu
- Center for AIDS Health Disparities Research, Department of Microbiology and Immunology, Meharry Medical College, Nashville, Tennessee, United States of America
| | - Xiaojian Wu
- Institute of Gastroenterology and the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Lei Wang
- Institute of Gastroenterology and the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jianping Wang
- Institute of Gastroenterology and the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- * E-mail: (HLL); (JPW)
| | - Huanliang Liu
- Institute of Gastroenterology and the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Human Virology, Sun Yat-sen University, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, Guangdong, China
- * E-mail: (HLL); (JPW)
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Li X, Li Z, Li N, Qi J, Fan K, Yin P, Zhao C, Liu Y, Yao W, Cai X, Wang L, Zha X. MAGI2 enhances the sensitivity of BEL-7404 human hepatocellular carcinoma cells to staurosporine-induced apoptosis by increasing PTEN stability. Int J Mol Med 2013; 32:439-47. [PMID: 23754155 DOI: 10.3892/ijmm.2013.1411] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Accepted: 04/29/2013] [Indexed: 11/05/2022] Open
Abstract
Adaptor proteins are involved in the assembly of various intracellular complexes and the regulation of cellular functions. Membrane-associated guanylate kinase inverted 2 (MAGI2), also known as synaptic scaffolding molecule (S-SCAM), plays a critical role in signal transduction by assembling and anchoring its ligands. However, the role of MAGI2 in mediating apoptosis remains largely unknown. In the present study, BEL-7404 human hepatocellular carcinoma cells were transfected with a plasmid containing myc-MAGI2 or an empty plasmid and cell viability was then determined using the Cell Counting kit-8. Apoptosis was also detected using an Annexin V apoptosis assay. The cells were then treated with various doses of staurosporine (STS) for different periods of time. The overexpression of myc-MAGI2 was found to sensitize the BEL-7404 cells to apoptosis in response to STS in a time- and dose-dependent manner. Our results demonstrated that MAGI2 enhanced STS-induced apoptosis by increasing the protein expression of cytoplasmic phosphatase and tensin homologue deleted on chromosome 10 (PTEN) and decreasing its protein degradation. The apoptotic sensitivity of the cells caused by the overexpression of myc-MAGI2 was reversed by the silencing of PTEN expression by PTEN siRNA, thus revealing a momentous role of PTEN in the enhancement of the sensitivity of cancer cells to STS-induced apoptosis by MAGI2. Finally, we observed that the MAGI-PTEN complex triggered by MAGI2 overexpression reduced the phosphorylation levels of AKT. These results suggest that MAGI2 overexpression enhances the sensitivity of cancer cells harboring ectopic PTEN to STS-induced apoptosis.
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Affiliation(s)
- Xin Li
- Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Fudan University, Shanghai 200032, P.R. China
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145
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Danescu A, Herrero Gonzalez S, Di Cristofano A, Mai S, Hombach-Klonisch S. Three-dimensional nuclear telomere architecture changes during endometrial carcinoma development. Genes Chromosomes Cancer 2013; 52:716-32. [PMID: 23630056 DOI: 10.1002/gcc.22067] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Accepted: 03/21/2013] [Indexed: 01/06/2023] Open
Abstract
Endometrioid or type-I endometrial carcinoma (EC) develops from hyperproliferative glandular pathologies. Inactivation of the tumor suppressor gene PTEN is frequently associated with type-I EC. Using a previously characterized Pten heterozygous (Pten+/-) mouse model, this study investigates the three-dimensional (3D) telomere profiles during progression from hyperplastic lesions to EC to test the hypothesis that altered 3D telomere profiles can be detected prior to Pten loss in early hyperproliferative lesions. We used immunohistochemistry and 3D-telomere fluorescent in-situ hybridization to investigate Pten expression, telomere length and signal distribution, average number and spatial distribution of telomeres and formation of telomere aggregates in uterine glandular epithelial cells from wildtype and Pten+/- mice. Pten showed nuclear and cytoplasmic localization in WT, predominantly cytoplasmic staining in simple hyperplasia (SH) and was markedly reduced in atypical hyperplasia (AH). Telomere length in glandular epithelial cells does not shorten with age. The average number of telomeres per nucleus was not different in WT and Pten+/- mice indicating the lack of substantial numeric chromosome aberrations during EC development. We observed telomere aggregates in lesions of AH and EC. SH lesions in Pten+/- mice differed from normal glandular epithelium by an increased relative number of shorter telomeres and by a telomere signal distribution indicative of a heterogeneous cell population. Our study revealed that alterations in the nuclear 3D telomere architecture are present in early proliferative lesions of mouse uterine tissues indicative of EC development. The changes in telomere length distribution and nuclear signal distribution precede the loss of Pten.
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Affiliation(s)
- Adrian Danescu
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Canada
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146
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Kalin A, Merideth MA, Regier DS, Blumenthal GM, Dennis PA, Stratton P. Management of reproductive health in Cowden syndrome complicated by endometrial polyps and breast cancer. Obstet Gynecol 2013. [PMID: 23344409 DOI: http://10 1097/aog.0b013e318270444f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Cowden syndrome is an autosomal-dominant condition associated with mutations in the tumor suppressor gene PTEN. Gynecologic malignancies are common with a 5-10% risk of endometrial cancer and 25-50% risk of breast cancer. CASE A 37-year-old woman with a history of breast cancer, other neoplasms, and multiple skin lesions was diagnosed with Cowden syndrome after a germline PTEN mutation was identified. The endometrium had high glucose uptake on positron emission tomography scan and was irregularly thickened on ultrasonography; biopsy revealed endometrial polyps and simple hyperplasia. Fifteen months later, hysteroscopy again confirmed numerous benign endometrial polyps. CONCLUSION Recurrent, multiple endometrial polyps portend a high risk of endometrial cancer in women with Cowden syndrome. Monitoring for malignancy and consideration of hysterectomy after childbearing is completed is warranted.
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Affiliation(s)
- Asli Kalin
- University College London Hospitals, London, United Kingdom; the Medical Genetics Branch, National Human Genome Research Institute, the Intramural Office of Rare Diseases, Office of the Director, the Medical Oncology Branch, Center for Cancer Research, National Cancer Institute, and the Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; and Children's National Medical Center, Department of Pediatrics, Washington, DC
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147
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Patel R, Gao M, Ahmad I, Fleming J, Singh LB, Rai TS, McKie AB, Seywright M, Barnetson RJ, Edwards J, Sansom OJ, Leung HY. Sprouty2, PTEN, and PP2A interact to regulate prostate cancer progression. J Clin Invest 2013; 123:1157-75. [PMID: 23434594 PMCID: PMC3582117 DOI: 10.1172/jci63672] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 01/03/2013] [Indexed: 12/16/2022] Open
Abstract
Concurrent activation of RAS/ERK and PI3K/AKT pathways is implicated in prostate cancer progression. The negative regulators of these pathways, including sprouty2 (SPRY2), protein phosphatase 2A (PP2A), and phosphatase and tensin homolog (PTEN), are commonly inactivated in prostate cancer. The molecular basis of cooperation between these genetic alterations is unknown. Here, we show that SPRY2 deficiency alone triggers activation of AKT and ERK, but this is insufficient to drive tumorigenesis. In addition to AKT and ERK activation, SPRY2 loss also activates a PP2A-dependent tumor suppressor checkpoint. Mechanistically, the PP2A-mediated growth arrest depends on GSK3β and is ultimately mediated by nuclear PTEN. In murine prostate cancer models, Pten haploinsufficiency synergized with Spry2 deficiency to drive tumorigenesis, including metastasis. Together, these results show that loss of Pten cooperates with Spry2 deficiency by bypassing a novel tumor suppressor checkpoint. Furthermore, loss of SPRY2 expression correlates strongly with loss of PTEN and/or PP2A subunits in human prostate cancer. This underlines the cooperation between SPRY2 deficiency and PTEN or PP2A inactivation in promoting tumorigenesis. Overall, we propose SPRY2, PTEN, and PP2A status as an important determinant of prostate cancer progression. Characterization of this trio may facilitate patient stratification for targeted therapies and chemopreventive interventions.
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Affiliation(s)
- Rachana Patel
- The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom.
Department of Pathology, National Health Service, Glasgow, United Kingdom
| | - Meiling Gao
- The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom.
Department of Pathology, National Health Service, Glasgow, United Kingdom
| | - Imran Ahmad
- The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom.
Department of Pathology, National Health Service, Glasgow, United Kingdom
| | - Janis Fleming
- The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom.
Department of Pathology, National Health Service, Glasgow, United Kingdom
| | - Lukram B. Singh
- The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom.
Department of Pathology, National Health Service, Glasgow, United Kingdom
| | - Taranjit Singh Rai
- The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom.
Department of Pathology, National Health Service, Glasgow, United Kingdom
| | - Arthur B. McKie
- The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom.
Department of Pathology, National Health Service, Glasgow, United Kingdom
| | - Morag Seywright
- The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom.
Department of Pathology, National Health Service, Glasgow, United Kingdom
| | - Robert J. Barnetson
- The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom.
Department of Pathology, National Health Service, Glasgow, United Kingdom
| | - Joanne Edwards
- The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom.
Department of Pathology, National Health Service, Glasgow, United Kingdom
| | - Owen J. Sansom
- The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom.
Department of Pathology, National Health Service, Glasgow, United Kingdom
| | - Hing Y. Leung
- The Beatson Institute for Cancer Research, Glasgow, United Kingdom.
Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom.
Department of Pathology, National Health Service, Glasgow, United Kingdom
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148
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Abstract
The PI3K-PTEN-AKT signaling pathway is involved in various cellular activities, including proliferation, migration, cell growth, cell survival and differentiation during adult homeostasis as well as in tumorigenesis. It has been suggested that the constitutive activation of PI3K/AKT signaling with concurrent loss of function of the tumor suppressor molecule PTEN contributes to cancer formation. Members of the PI3K-PTEN-AKT pathway, including these proteins and mTOR, are altered in melanoma tumors and cell lines. A hallmark of activation of the pathway is the loss of function of PTEN. Indeed, loss of heterozygosity of PTEN has been observed in approximately 30% of human melanomas, implicating this signaling pathway in this cancer. PI3K signaling activation, via loss of PTEN function, can inhibit proapoptotic genes such as the FoxO family of transcription factors, while inducing cell growth- and cell survival-related elements such as p70S6K and AKT. Determining how the PI3K-PTEN-AKT signaling pathway, alone or in cooperation with other pathways, orchestrates the induction of target genes involved in a diverse range of activities is a major challenge in research into melanoma initiation and progression. Moreover, the acquisition of basic knowledge will help patient management with appropriate therapies that are already, or will shortly be, on the market.
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Affiliation(s)
- Alejandro Conde-Perez
- Institut Curie, Developmental Genetics of Melanocytes, Bat. 110, 91405, Orsay, France
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149
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Zheng M, Liao M, Cui T, Tian H, Fan DS, Wan Q. Regulation of nuclear TDP-43 by NR2A-containing NMDA receptors and PTEN. J Cell Sci 2013; 125:1556-67. [PMID: 22526419 DOI: 10.1242/jcs.095729] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The dysfunction of TAR DNA-binding protein-43 (TDP-43) is implicated in neurodegenerative diseases. However, the function of TDP-43 is not fully elucidated. Here we show that the protein level of endogenous TDP-43 in the nucleus is increased in mouse cortical neurons in the early stages, but return to basal level in the later stages after glutamate accumulation-induced injury. The elevation of TDP-43 results from a downregulation of phosphatase and tensin homolog (PTEN). We further demonstrate that activation of NR2A-containing NMDA receptors (NR2ARs) leads to PTEN downregulation and subsequent reduction of PTEN import from the cytoplasm to the nucleus after glutamate accumulation. The decrease of PTEN in the nucleus contributes to its reduced association with TDP-43, and thereby mediates the elevation of nuclear TDP-43. We provide evidence that the elevation of nuclear TDP-43, mediated by NR2AR activation and PTEN downregulation, confers protection against cortical neuronal death in the late stages after glutamate accumulation. Thus, this study reveals a NR2AR-PTEN-TDP-43 signaling pathway by which nuclear TDP-43 promotes neuronal survival. These results suggest that upregulation of nuclear TDP-43 represents a self-protection mechanism to delay neurodegeneration in the early stages after glutamate accumulation and that prolonging the upregulation process of nuclear TDP-43 might have therapeutic significance.
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Affiliation(s)
- Mei Zheng
- Department of Neurology, Peking University Third Hospital, 49 North Garden Road, Beijing, 100191, China
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150
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Management of Reproductive Health in Cowden Syndrome Complicated by Endometrial Polyps and Breast Cancer. Obstet Gynecol 2013. [DOI: 10.1097/aog.0b013e318270444f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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