1
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Sloth RA, Axelsen TV, Espejo MS, Toft NJ, Voss NCS, Burton M, Thomassen M, Vahl P, Boedtkjer E. Loss of RPTPγ primes breast tissue for acid extrusion, promotes malignant transformation and results in early tumour recurrence and shortened survival. Br J Cancer 2022; 127:1226-1238. [PMID: 35821297 DOI: 10.1038/s41416-022-01911-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/22/2022] [Accepted: 06/29/2022] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND While cellular metabolism and acidic waste handling accelerate during breast carcinogenesis, temporal patterns of acid-base regulation and underlying molecular mechanisms responding to the tumour microenvironment remain unclear. METHODS We explore data from human cohorts and experimentally investigate transgenic mice to evaluate the putative extracellular HCO3--sensor Receptor Protein Tyrosine Phosphatase (RPTP)γ during breast carcinogenesis. RESULTS RPTPγ expression declines during human breast carcinogenesis and particularly in high-malignancy grade breast cancer. Low RPTPγ expression associates with poor prognosis in women with Luminal A or Basal-like breast cancer. RPTPγ knockout in mice favours premalignant changes in macroscopically normal breast tissue, accelerates primary breast cancer development, promotes malignant breast cancer histopathologies, and shortens recurrence-free survival. In RPTPγ knockout mice, expression of Na+,HCO3--cotransporter NBCn1-a breast cancer susceptibility protein-is upregulated in normal breast tissue but, contrary to wild-type mice, shows no further increase during breast carcinogenesis. Associated augmentation of Na+,HCO3--cotransport in normal breast tissue from RPTPγ knockout mice elevates steady-state intracellular pH, which has known pro-proliferative effects. CONCLUSIONS Loss of RPTPγ accelerates cellular net acid extrusion and elevates NBCn1 expression in breast tissue. As these effects precede neoplastic manifestations in histopathology, we propose that RPTPγ-dependent enhancement of Na+,HCO3--cotransport primes breast tissue for cancer development.
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Affiliation(s)
- Rasmus A Sloth
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Trine V Axelsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Nicolai J Toft
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Ninna C S Voss
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Mark Burton
- Department of Clinical Genetics, University of Southern Denmark, Odense, Denmark.,Clinical Genome Center, University and Region of Southern Denmark, Odense, Denmark.,Department of Clinical Medicine, University of Southern Denmark, Odense, Denmark
| | - Mads Thomassen
- Department of Clinical Genetics, University of Southern Denmark, Odense, Denmark.,Clinical Genome Center, University and Region of Southern Denmark, Odense, Denmark
| | - Pernille Vahl
- Department of Pathology, Aarhus University Hospital, Aarhus, Denmark
| | - Ebbe Boedtkjer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.
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2
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Boni C, Sorio C. The Role of the Tumor Suppressor Gene Protein Tyrosine Phosphatase Gamma in Cancer. Front Cell Dev Biol 2022; 9:768969. [PMID: 35071225 PMCID: PMC8766859 DOI: 10.3389/fcell.2021.768969] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 12/16/2021] [Indexed: 12/31/2022] Open
Abstract
Members of the Protein Tyrosine Phosphatase (PTPs) family are associated with growth regulation and cancer development. Acting as natural counterpart of tyrosine kinases (TKs), mainly involved in crucial signaling pathways such as regulation of cell cycle, proliferation, invasion and angiogenesis, they represent key parts of complex physiological homeostatic mechanisms. Protein tyrosine phosphatase gamma (PTPRG) is classified as a R5 of the receptor type (RPTPs) subfamily and is broadly expressed in various isoforms in different tissues. PTPRG is considered a tumor-suppressor gene (TSG) mapped on chromosome 3p14-21, a region frequently subject to loss of heterozygosity in various tumors. However, reported mechanisms of PTPRG downregulation include missense mutations, ncRNA gene regulation and epigenetic silencing by hypermethylation of CpG sites on promoter region causing loss of function of the gene product. Inactive forms or total loss of PTPRG protein have been described in sporadic and Lynch syndrome colorectal cancer, nasopharyngeal carcinoma, ovarian, breast, and lung cancers, gastric cancer or diseases affecting the hematopoietic compartment as Lymphoma and Leukemia. Noteworthy, in Central Nervous System (CNS) PTPRZ/PTPRG appears to be crucial in maintaining glioblastoma cell-related neuronal stemness, carving out a pathological functional role also in this tissue. In this review, we will summarize the current knowledge on the role of PTPRG in various human cancers.
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Affiliation(s)
- Christian Boni
- Department of Medicine, General Pathology Division, University of Verona, Verona, Italy
| | - Claudio Sorio
- Department of Medicine, General Pathology Division, University of Verona, Verona, Italy
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3
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Mafficini A, Vezzalini M, Zamai L, Galeotti L, Bergamini G, Peruta MD, Melotti P, Sorio C. Protein Tyrosine Phosphatase Gamma (PTPγ) is a Novel Leukocyte Marker Highly Expressed by CD34+ Precursors. Biomark Insights 2017. [DOI: 10.1177/117727190700200036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Protein Tyrosine Phosphatase gamma (PTPγ) is a receptor-like transmembrane protein belonging to the family of classical protein tyrosine phosphatases. PTPγ is known to regulate haematopoietic differentiation in a murine embryonic stem cells model. We have recently demonstrated that PTPγ mRNA is expressed in monocytes, tissue-localized myeloid dendritic cells and in both myeloid and plasmacytoid dendritic cells in peripheral blood. We now developed a PTPγ specific antibody that recognizes the protein by flow cytometry. PTPγ expression was detected in monocytes and both myeloid and plasmacytoid dendritic cells, while PMN showed a low but consistent staining in contrast with previous mRNA data. B cells were found to express the phosphatase while T cells were negative. In keeping with RNA data, PTPγ was detected in monocyte-derived dendritic cells and its expression rose upon LPS stimulation. Finally, we discovered that CD34+ haematopoietic precursors express high PTPγ level that drops during in vitro expansion induced by IL-3 and SCF growth factors. We therefore propose PTPγ as a new functionally regulated leukocyte marker whose role in normal and pathological context deserve further investigation.
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Affiliation(s)
| | | | - Loris Zamai
- Institute of Histology and Laboratory Analysis, University of Urbino “Carlo Bo”, Italy
- Flow Cytometry and Cytomorphology Center, University of Urbino “Carlo Bo”, Italy
- INFN-Gran Sasso National Laboratory, SS17bis km 18+910, 67010 Assergi, L'Aquila, Italy
| | - Laura Galeotti
- Institute of Histology and Laboratory Analysis, University of Urbino “Carlo Bo”, Italy
- Flow Cytometry and Cytomorphology Center, University of Urbino “Carlo Bo”, Italy
| | | | | | - Paola Melotti
- Cystic Fibrosis Center, Azienda Ospedaliera of Verona, Verona, Italy
| | - Claudio Sorio
- Department of Pathology, University of Verona, Italy
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4
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Vezzalini M, Mafficini A, Tomasello L, Lorenzetto E, Moratti E, Fiorini Z, Holyoake TL, Pellicano F, Krampera M, Tecchio C, Yassin M, Al-Dewik N, Ismail MA, Al Sayab A, Monne M, Sorio C. A new monoclonal antibody detects downregulation of protein tyrosine phosphatase receptor type γ in chronic myeloid leukemia patients. J Hematol Oncol 2017. [PMID: 28637510 PMCID: PMC5479035 DOI: 10.1186/s13045-017-0494-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Protein tyrosine phosphatase receptor gamma (PTPRG) is a ubiquitously expressed member of the protein tyrosine phosphatase family known to act as a tumor suppressor gene in many different neoplasms with mechanisms of inactivation including mutations and methylation of CpG islands in the promoter region. Although a critical role in human hematopoiesis and an oncosuppressor role in chronic myeloid leukemia (CML) have been reported, only one polyclonal antibody (named chPTPRG) has been described as capable of recognizing the native antigen of this phosphatase by flow cytometry. Protein biomarkers of CML have not yet found applications in the clinic, and in this study, we have analyzed a group of newly diagnosed CML patients before and after treatment. The aim of this work was to characterize and exploit a newly developed murine monoclonal antibody specific for the PTPRG extracellular domain (named TPγ B9-2) to better define PTPRG protein downregulation in CML patients. METHODS TPγ B9-2 specifically recognizes PTPRG (both human and murine) by flow cytometry, western blotting, immunoprecipitation, and immunohistochemistry. RESULTS Co-localization experiments performed with both anti-PTPRG antibodies identified the presence of isoforms and confirmed protein downregulation at diagnosis in the Philadelphia-positive myeloid lineage (including CD34+/CD38bright/dim cells). After effective tyrosine kinase inhibitor (TKI) treatment, its expression recovered in tandem with the return of Philadelphia-negative hematopoiesis. Of note, PTPRG mRNA levels remain unchanged in tyrosine kinase inhibitors (TKI) non-responder patients, confirming that downregulation selectively occurs in primary CML cells. CONCLUSIONS The availability of this unique antibody permits its evaluation for clinical application including the support for diagnosis and follow-up of these disorders. Evaluation of PTPRG as a potential therapeutic target is also facilitated by the availability of a specific reagent capable to specifically detect its target in various experimental conditions.
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Affiliation(s)
- Marzia Vezzalini
- Department of Medicine, University of Verona, Strada le Grazie 8, 37134, Verona, Italy
| | - Andrea Mafficini
- Department of Medicine, University of Verona, Strada le Grazie 8, 37134, Verona, Italy.,ARC-Net Research Centre, University and Hospital Trust of Verona, 37134, Verona, Italy
| | - Luisa Tomasello
- Department of Medicine, University of Verona, Strada le Grazie 8, 37134, Verona, Italy.,Present address: The Ohio State University, Wexner Medical Center Biomedical Research Tower, 460W 12th Avenue, room 1070, Columbus, OH, 43210, USA
| | - Erika Lorenzetto
- Section of Physiology, Department of Neurological, Neuropsychological, Morphological and Motor Sciences, University of Verona, Verona, Italy
| | - Elisabetta Moratti
- Department of Medicine, University of Verona, Strada le Grazie 8, 37134, Verona, Italy
| | - Zeno Fiorini
- Department of Medicine, University of Verona, Strada le Grazie 8, 37134, Verona, Italy
| | - Tessa L Holyoake
- Paul O'Gorman Leukaemia Research Centre, College of Medical, Veterinary & Life Sciences, Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Francesca Pellicano
- The Beatson Institute for Cancer Research, Garscube Estate, Switchback Road, Bearsden, Glasgow, G61 1BD, Scotland, UK
| | - Mauro Krampera
- Section of Hematology, Department of Medicine, University of Verona, Verona, Italy
| | - Cristina Tecchio
- Section of Hematology, Department of Medicine, University of Verona, Verona, Italy
| | - Mohamed Yassin
- National Center for Cancer Care and Research (NCCCR), Hamad Medical Corporation (HMC), Doha, Qatar
| | - Nader Al-Dewik
- Qatar Medical Genetics Center, Hamad Medical Corporation (HMC), Doha, Qatar
| | - Mohamed A Ismail
- Interim Translational Research Institute (iTRI), Hamad Medical Corporation, Doha, Qatar
| | - Ali Al Sayab
- National Center for Cancer Care and Research (NCCCR), Hamad Medical Corporation (HMC), Doha, Qatar
| | - Maria Monne
- Centro di Diagnostica Biomolecolare e Citogenetica Emato-Oncologica, "San Francesco" Hospital, ASL3, Nuoro, 08100, Italy
| | - Claudio Sorio
- Department of Medicine, University of Verona, Strada le Grazie 8, 37134, Verona, Italy.
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5
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Liu M, Yang R, Urrehman U, Ye C, Yan X, Cui S, Hong Y, Gu Y, Liu Y, Zhao C, Yan L, Zhang CY, Liang H, Chen X. MiR-19b suppresses PTPRG to promote breast tumorigenesis. Oncotarget 2016; 7:64100-64108. [PMID: 27602768 PMCID: PMC5325428 DOI: 10.18632/oncotarget.11799] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 08/22/2016] [Indexed: 11/25/2022] Open
Abstract
Protein tyrosine phosphatase receptor type G (PTPRG) is an important tumor suppressor gene in multiple human cancers. In this study, we found that PTPRG protein levels were downregulated in breast cancer tissues while the mRNA levels varied irregularly, implying a post-transcriptional mechanism was involved. Because microRNAs are powerful post-transcriptional regulators of gene expression, we used bioinformatics analysis to search for microRNAs that potentially targets PTPRG in the setting of breast cancer. We identified two specific binding sites for miR-19b in the 3′-untranslated region of PTPRG. We further identified an inverse correlation between miR-19b and PTPRG protein levels, but not mRNA levels, in human breast cancer tissues. By overexpressing or knocking down miR-19b in MCF-7 cells and MDA-231 cells, we experimentally confirmed that miR-19b directly suppresses PTPRG expression. Furthermore, we determined that the inhibition of PTPRG by miR-19b leads to increased proliferation, stimulated cell migration and reduced apoptosis. Taken together, our findings provide the first evidence that miR-19b inhibits PTPRG expression to promote tumorigenesis in human breast cancer.
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Affiliation(s)
- Minghui Liu
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210046, China
| | - Rong Yang
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210046, China.,Department of Urology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu 210008, China
| | - Uzair Urrehman
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210046, China
| | - Chao Ye
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210046, China
| | - Xin Yan
- Department of Respiratory Medicine, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu 210008, China
| | - Shufang Cui
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210046, China
| | - Yeting Hong
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210046, China
| | - Yuanyuan Gu
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210046, China
| | - Yanqing Liu
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210046, China
| | - Chihao Zhao
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210046, China
| | - Liang Yan
- Provincial Key Laboratory of Biological Macro-Molecules Research, Wannan Medical College, Wuhu, Anhui 241002, China
| | - Chen-Yu Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210046, China
| | - Hongwei Liang
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210046, China
| | - Xi Chen
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210046, China
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6
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Cheung AKL, Ip JCY, Chu ACH, Cheng Y, Leong MML, Ko JMY, Shuen WH, Lung HL, Lung ML. PTPRG suppresses tumor growth and invasion via inhibition of Akt signaling in nasopharyngeal carcinoma. Oncotarget 2016; 6:13434-47. [PMID: 25970784 PMCID: PMC4537025 DOI: 10.18632/oncotarget.3876] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/03/2015] [Indexed: 01/01/2023] Open
Abstract
Protein Tyrosine Phosphatase, Receptor Type G (PTPRG) was identified as a candidate tumor suppressor gene in nasopharyngeal carcinoma (NPC). PTPRG induces significant in vivo tumor suppression in NPC. We identified EGFR as a PTPRG potential interacting partner and examined this interaction. Dephosphorylation of EGFR at EGFR-Y1068 and -Y1086 sites inactivated the PI3K/Akt signaling cascade and subsequent down-regulation of downstream pro-angiogenic and -invasive proteins (VEGF, IL6, and IL8) and suppressed tumor cell proliferation, angiogenesis, and invasion. The effect of Akt inhibition in NPC cells was further validated by Akt knockdown experiments in the PTPRG-down-regulated NPC cell lines. Our results suggested that inhibition of Akt in NPC cells induces tumor suppression at both the in vitro and in vivo levels, and also importantly, in vivo metastasis. In conclusion, we confirmed the vital role of PTPRG in inhibiting Akt signaling with the resultant suppression of in vivo tumorigenesis and metastasis.
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Affiliation(s)
- Arthur Kwok Leung Cheung
- Department of Clinical Oncology, University of Hong Kong, Hong Kong (SAR), People's Republic of China.,Centre for Cancer Research, University of Hong Kong, Hong Kong (SAR), People's Republic of China
| | - Joseph Chok Yan Ip
- Department of Clinical Oncology, University of Hong Kong, Hong Kong (SAR), People's Republic of China
| | - Adrian Chi Hang Chu
- Department of Clinical Oncology, University of Hong Kong, Hong Kong (SAR), People's Republic of China
| | - Yue Cheng
- Department of Clinical Oncology, University of Hong Kong, Hong Kong (SAR), People's Republic of China.,Centre for Cancer Research, University of Hong Kong, Hong Kong (SAR), People's Republic of China
| | - Merrin Man Long Leong
- Department of Clinical Oncology, University of Hong Kong, Hong Kong (SAR), People's Republic of China
| | - Josephine Mun Yee Ko
- Department of Clinical Oncology, University of Hong Kong, Hong Kong (SAR), People's Republic of China
| | - Wai Ho Shuen
- Department of Clinical Oncology, University of Hong Kong, Hong Kong (SAR), People's Republic of China.,Division of Medical Oncology, National Cancer Centre, Singapore
| | - Hong Lok Lung
- Department of Clinical Oncology, University of Hong Kong, Hong Kong (SAR), People's Republic of China.,Centre for Cancer Research, University of Hong Kong, Hong Kong (SAR), People's Republic of China
| | - Maria Li Lung
- Department of Clinical Oncology, University of Hong Kong, Hong Kong (SAR), People's Republic of China.,Centre for Cancer Research, University of Hong Kong, Hong Kong (SAR), People's Republic of China.,Centre for Nasopharyngeal Carcinoma Research, University of Hong Kong, Hong Kong (SAR), People's Republic of China
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7
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Zhao W, Luo J, Jiao S. Comprehensive characterization of cancer subtype associated long non-coding RNAs and their clinical implications. Sci Rep 2014; 4:6591. [PMID: 25307233 PMCID: PMC4194441 DOI: 10.1038/srep06591] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/08/2014] [Indexed: 12/15/2022] Open
Abstract
Long non-coding RNAs (lncRNAs) are a kind of RNAs with regulation that participate fundamental cellular processes via diverse mechanisms. Despite the potential importance of lncRNAs in multiple kinds of cancer has been well studied, no comprehensive survey of cancer subtype associated lncRNAs. Here, we performed an array-based transcriptional survey of lncRNAs across 150 lung cancer samples comprising both adenocarcinoma and squamous cell carcinoma, and 306 breast cancer patients with clear clinical information. In lung cancer, 72 lncRNAs are identified to be associated with tumor subtypes and their functions as well as the associated proteins are predicted by constructing coding-non-coding co-expression network. The results suggest that they are mostly related with epidermis development, cell adhesion and response to stimulus. The validation results show the high concordance and confirmed the robust of the identification results. In breast cancer, we found 3 lncRNA genes are associated with estrogen receptor α (ER) positive and ER negative subtypes and tumor histologic grade. Survival (Kaplan-Meier) analysis results suggest that the expression pattern of the 3 lncRNAs is significantly correlated with clinical outcomes. The current study provides the first large-scale survey of lncRNAs within cancer subtypes, and may offer new targets for their diagnosis, therapy and prognosis.
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Affiliation(s)
- Weihong Zhao
- Department of Medical Oncology, the General Hospital of the People's Liberation Army, Beijing, China
| | - Jiancheng Luo
- Solomonbrothers Medical Institute, Wilmington, New Castle DE, USA
| | - Shunchang Jiao
- Department of Medical Oncology, the General Hospital of the People's Liberation Army, Beijing, China
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8
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Li SY, Li R, Chen YL, Xiong LK, Wang HL, Rong L, Luo RC. Aberrant PTPRO methylation in tumor tissues as a potential biomarker that predicts clinical outcomes in breast cancer patients. BMC Genet 2014; 15:67. [PMID: 24919593 PMCID: PMC4062905 DOI: 10.1186/1471-2156-15-67] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 06/04/2014] [Indexed: 01/31/2023] Open
Abstract
Background Aberrant hypermethylation of gene promoter regions is a primary mechanism by which tumor suppressor genes become inactivated in breast cancer. Epigenetic inactivation of the protein tyrosine phosphatase receptor-type O gene (PTPRO) has been described in several types of cancer. Results We screened primary breast cancer tissues for PTPRO promoter hypermethylation and assessed potential associations with pathological features and patient outcome. We also evaluated its potential as a breast cancer biomarker. PTPRO methylation was observed in 53 of 98 (54%) breast cancer tissues but not in adjacent normal tissue. Among matched peripheral blood samples from breast cancer patients, 33 of 98 (34%) exhibited methylated PTPRO in plasma. In contrast, no methylated PTPRO was observed in normal peripheral blood from 30 healthy individuals. PTPRO methylation was positively associated with lymph node involvement (P = 0.014), poorly differentiated histology (P = 0.037), depth of invasion (P = 0.004), and HER2 amplification (P = 0.001). Multivariate analysis indicated that aberrant PTPRO methylation could serve as an independent predictor for overall survival hazard ratio (HR): 2.7; 95% CI: 1.1-6.2; P = 0.023), especially for patients with HER2-positive (hazard ratio (HR): 7.5; 95% CI: 1.8-31.3; P = 0.006), but not in ER + and PR + subpopulation. In addition, demethylation induced by 5-azacytidine led to gene reactivation in PTPRO-methylated and -silenced breast cancer cell lines. Conclusions Here, we report that tumor PTPRO methylation is a strong prognostic factor in breast cancer. Methylation of PTPRO silences its expression and plays an important role in breast carcinogenesis. The data we present here may provide insight into the development of novel therapies for breast cancer treatment. Additionally, detection of PTPRO methylation in peripheral blood of breast cancer patients may provide a noninvasive means to diagnose and monitor the disease.
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Affiliation(s)
- Shao-ying Li
- Department of Breast Surgery, Bao'an Maternal and Child Health Hospital, Shenzhen, People's Republic of China.
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9
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Nunes-Xavier CE, Martín-Pérez J, Elson A, Pulido R. Protein tyrosine phosphatases as novel targets in breast cancer therapy. Biochim Biophys Acta Rev Cancer 2013; 1836:211-26. [PMID: 23756181 DOI: 10.1016/j.bbcan.2013.06.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 06/01/2013] [Indexed: 02/07/2023]
Abstract
Breast cancer is linked to hyperactivation of protein tyrosine kinases (PTKs), and recent studies have unveiled that selective tyrosine dephosphorylation by protein tyrosine phosphatases (PTPs) of specific substrates, including PTKs, may activate or inactivate oncogenic pathways in human breast cancer cell growth-related processes. Here, we review the current knowledge on the involvement of PTPs in breast cancer, as major regulators of breast cancer therapy-targeted PTKs, such as HER1/EGFR, HER2/Neu, and Src. The functional interplay between PTKs and PTK-activating or -inactivating PTPs, and its implications in novel breast cancer therapies based on targeting of specific PTPs, are discussed.
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Affiliation(s)
- Caroline E Nunes-Xavier
- BioCruces Health Research Institute, Hospital de Cruces, Plaza Cruces s/n, 48903 Barakaldo, Spain
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10
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Abstract
BACKGROUND Endocrine disrupters have been shown to affect the male and female reproductive systems and to alter potential fertility. OBJECTIVES This study was conducted to evaluate the effect of a continuous-release pellet containing 12 mg of zeranol for 30 days on the testes and the prostate gland of mature male rats. RESULTS Zeranol treatment induced significant decrease of the testes and the prostate gland weights which were associated with a remarkable atrophy of the testicular seminiferous tubules and prominent regression of the glandular compartment of the prostate gland. However, zeranol treatment increased the thickness of the periductal layer of stromal cells of the prostate gland from a thin layer that express intense immunostaining of SM-actin and mild vimentin to a thicker layer of cells that exhibited intense immunostaining for both SM-actin and vimentin. CONCLUSION These findings suggest that zeranol-induced changes to the prostate gland could result from either a direct effect of zeranol on the prostate gland or an indirect effect by interfering with testosterone production through disruption of testicular function.
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Affiliation(s)
- Falah Shidaifat
- Laboratory of Reproductive and Molecular Endocrinology, College of Veterinary Medicine, The Ohio State University , 1900 Coffey Road, Columbus, OH , USA
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11
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Labbé DP, Hardy S, Tremblay ML. Protein tyrosine phosphatases in cancer: friends and foes! PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 106:253-306. [PMID: 22340721 DOI: 10.1016/b978-0-12-396456-4.00009-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Tyrosine phosphorylation of proteins serves as an exquisite switch in controlling several key oncogenic signaling pathways involved in cell proliferation, apoptosis, migration, and invasion. Since protein tyrosine phosphatases (PTPs) counteract protein kinases by removing phosphate moieties on target proteins, one may intuitively think that PTPs would act as tumor suppressors. Indeed, one of the most described PTPs, namely, the phosphatase and tensin homolog (PTEN), is a tumor suppressor. However, a growing body of evidence suggests that PTPs can also function as potent oncoproteins. In this chapter, we provide a broad historical overview of the PTPs, their mechanism of action, and posttranslational modifications. Then, we focus on the dual properties of classical PTPs (receptor and nonreceptor) and dual-specificity phosphatases in cancer and summarize the current knowledge of the signaling pathways regulated by key PTPs in human cancer. In conclusion, we present our perspective on the potential of these PTPs to serve as therapeutic targets in cancer.
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Affiliation(s)
- David P Labbé
- Goodman Cancer Research Centre, McGill University, Montréal, Québec, Canada
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12
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Rodriguez-Martinez A, Alarmo EL, Saarinen L, Ketolainen J, Nousiainen K, Hautaniemi S, Kallioniemi A. Analysis of BMP4 and BMP7 signaling in breast cancer cells unveils time-dependent transcription patterns and highlights a common synexpression group of genes. BMC Med Genomics 2011; 4:80. [PMID: 22118688 PMCID: PMC3229454 DOI: 10.1186/1755-8794-4-80] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 11/25/2011] [Indexed: 11/10/2022] Open
Abstract
Background Bone morphogenetic proteins (BMPs) are members of the TGF-beta superfamily of growth factors. They are known for their roles in regulation of osteogenesis and developmental processes and, in recent years, evidence has accumulated of their crucial functions in tumor biology. BMP4 and BMP7, in particular, have been implicated in breast cancer. However, little is known about BMP target genes in the context of tumor. We explored the effects of BMP4 and BMP7 treatment on global gene transcription in seven breast cancer cell lines during a 6-point time series, using a whole-genome oligo microarray. Data analysis included hierarchical clustering of differentially expressed genes, gene ontology enrichment analyses and model based clustering of temporal data. Results Both ligands had a strong effect on gene expression, although the response to BMP4 treatment was more pronounced. The cellular functions most strongly affected by BMP signaling were regulation of transcription and development. The observed transcriptional response, as well as its functional outcome, followed a temporal sequence, with regulation of gene expression and signal transduction leading to changes in metabolism and cell proliferation. Hierarchical clustering revealed distinct differences in the response of individual cell lines to BMPs, but also highlighted a synexpression group of genes for both ligands. Interestingly, the majority of the genes within these synexpression groups were shared by the two ligands, probably representing the core molecular responses common to BMP4 and BMP7 signaling pathways. Conclusions All in all, we show that BMP signaling has a remarkable effect on gene transcription in breast cancer cells and that the functions affected follow a logical temporal pattern. Our results also uncover components of the common cellular transcriptional response to BMP4 and BMP7. Most importantly, this study provides a list of potential novel BMP target genes relevant in breast cancer.
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Affiliation(s)
- Alejandra Rodriguez-Martinez
- Laboratory of Cancer Genetics, Institute of Biomedical Technology, University of Tampere and Centre for Laboratory Medicine, Tampere University Hospital, Finland
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Sheriff S, Beno BR, Zhai W, Kostich WA, McDonnell PA, Kish K, Goldfarb V, Gao M, Kiefer SE, Yanchunas J, Huang Y, Shi S, Zhu S, Dzierba C, Bronson J, Macor JE, Appiah KK, Westphal RS, O’Connell J, Gerritz SW. Small Molecule Receptor Protein Tyrosine Phosphatase γ (RPTPγ) Ligands That Inhibit Phosphatase Activity via Perturbation of the Tryptophan–Proline–Aspartate (WPD) Loop. J Med Chem 2011; 54:6548-62. [DOI: 10.1021/jm2003766] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Steven Sheriff
- Bristol-Myers Squibb Research and Development, P.O. Box 4000, Princeton, New Jersey 08543-4000, United States
| | - Brett R. Beno
- Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Weixu Zhai
- Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Walter A. Kostich
- Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Patricia A. McDonnell
- Bristol-Myers Squibb Research and Development, P.O. Box 4000, Princeton, New Jersey 08543-4000, United States
| | - Kevin Kish
- Bristol-Myers Squibb Research and Development, P.O. Box 4000, Princeton, New Jersey 08543-4000, United States
| | - Valentina Goldfarb
- Bristol-Myers Squibb Research and Development, P.O. Box 4000, Princeton, New Jersey 08543-4000, United States
| | - Mian Gao
- Bristol-Myers Squibb Research and Development, P.O. Box 4000, Princeton, New Jersey 08543-4000, United States
| | - Susan E. Kiefer
- Bristol-Myers Squibb Research and Development, P.O. Box 4000, Princeton, New Jersey 08543-4000, United States
| | - Joseph Yanchunas
- Bristol-Myers Squibb Research and Development, P.O. Box 4000, Princeton, New Jersey 08543-4000, United States
| | - Yanling Huang
- Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Shuhao Shi
- Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Shirong Zhu
- Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Carolyn Dzierba
- Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Joanne Bronson
- Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - John E. Macor
- Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Kingsley K. Appiah
- Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Ryan S. Westphal
- Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Jonathan O’Connell
- Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
| | - Samuel W. Gerritz
- Bristol-Myers Squibb Research and Development, 5 Research Parkway, Wallingford, Connecticut 06492, United States
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Receptor tyrosine phosphatase PTPγ is a regulator of spinal cord neurogenesis. Mol Cell Neurosci 2010; 46:469-82. [PMID: 21112398 PMCID: PMC3038263 DOI: 10.1016/j.mcn.2010.11.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Revised: 10/12/2010] [Accepted: 11/17/2010] [Indexed: 12/12/2022] Open
Abstract
During spinal cord development the proliferation, migration and survival of neural progenitors and precursors is tightly controlled, generating the fine spatial organisation of the cord. In order to understand better the control of these processes, we have examined the function of an orphan receptor protein tyrosine phosphatase (RPTP) PTPγ, in the developing chick spinal cord. Widespread expression of PTPγ occurs post-embryonic day 3 in the early cord and is consistent with a potential role in either neurogenesis or neuronal maturation. Using gain-of-function and loss-of-function approaches in ovo, we show that PTPγ perturbation significantly reduces progenitor proliferation rates and neuronal precursor numbers, resulting in hypoplasia of the neuroepithelium. PTPγ gain-of-function causes widespread suppression of Wnt/β-catenin-driven TCF signalling. One potential target of PTPγ may therefore be β-catenin itself, since PTPγ can dephosphorylate it in vitro, but alternative targets are also likely. PTPγ loss-of-function is not sufficient to alter TCF signalling. Instead, loss-of-function leads to increased apoptosis and defective cell–cell adhesion in progenitors and precursors. Furthermore, motor neuron precursor migration is specifically defective. PTPγ therefore regulates neurogenesis during a window of spinal cord development, with molecular targets most likely related to Wnt/β-catenin signalling, cell survival and cell adhesion.
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15
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Xu P, Ye W, Zhong S, Jen R, Li H, Feng E, Lin SH, Liu JY, Lin YC. Zeranol may increase the risk of leptin-induced neoplasia in human breast. Oncol Lett 2010; 2:101-108. [PMID: 22870137 DOI: 10.3892/ol.2010.214] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Accepted: 10/01/2010] [Indexed: 11/06/2022] Open
Abstract
Breast cancer and obesity are serious health problems and their relationship has been studied for many years. Leptin is mainly secreted by adipocytes and plays a key role in breast cancer development. Leptin expression is up-regulated in obese individuals and promotes breast cancer cell growth. On the other hand, exposure to environmental estrogens has been found to be directly related to breast cancer. Zeranol (Z) is a non-steroidal anabolic growth promoter used in the beef industry in the US. This study focused on the evaluation of Z and Z-containing sera (ZS) and its adverse health risk to human consumption of Z-containing meat produced from Z-implanted beef cattle. We hypothesized that Z increases the risk of breast neoplasia in women, particularly in obese women. A cell proliferation assay, ELISA analysis, RT-PCR and Western blot analysis were conducted. Our study demonstrated that Z and ZS collected from Z-implanted heifers stimulated the proliferation of primary cultured human normal breast epithelial cells (HNBECs) by up-regulating cyclin D1 expression. Leptin increased the sensitivity of HNBECs to Z, and Z increased the ability of HNBECs to secrete leptin. These results suggest an interaction between leptin and Z in HNBECs. Furthermore, Z may play a role in leptin-induced breast neoplasia.
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Affiliation(s)
- Pingping Xu
- Laboratory of Reproductive and Molecular Endocrinology, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA
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16
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Della Peruta M, Martinelli G, Moratti E, Pintani D, Vezzalini M, Mafficini A, Grafone T, Iacobucci I, Soverini S, Murineddu M, Vinante F, Tecchio C, Piras G, Gabbas A, Monne M, Sorio C. Protein Tyrosine Phosphatase Receptor Type γ Is a Functional Tumor Suppressor Gene Specifically Downregulated in Chronic Myeloid Leukemia. Cancer Res 2010; 70:8896-906. [DOI: 10.1158/0008-5472.can-10-0258] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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17
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Baratz KH, Tosakulwong N, Ryu E, Brown WL, Branham K, Chen W, Tran KD, Schmid-Kubista KE, Heckenlively JR, Swaroop A, Abecasis G, Bailey KR, Edwards AO. E2-2 protein and Fuchs's corneal dystrophy. N Engl J Med 2010; 363:1016-24. [PMID: 20825314 DOI: 10.1056/nejmoa1007064] [Citation(s) in RCA: 193] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Fuchs's corneal dystrophy (FCD) is a leading cause of corneal transplantation and affects 5% of persons in the United States who are over the age of 40 years. Clinically visible deposits called guttae develop under the corneal endothelium in patients with FCD. A loss of endothelial cells and deposition of an abnormal extracellular matrix are observed microscopically. In advanced disease, the cornea swells and becomes cloudy because the remaining endothelial cells are not sufficient to keep the cornea dehydrated and clear. Although rare genetic variation that contributes to both early-onset and typical late-onset forms of FCD has been identified, to our knowledge, no common variants have been reported. METHODS We performed a genomewide association study and replicated the most significant observations in a second, independent group of subjects. RESULTS Alleles in the transcription factor 4 gene (TCF4), encoding a member of the E-protein family (E2-2), were associated with typical FCD (P=2.3x10(-26)). The association increased the odds of having FCD by a factor of 30 for persons with two copies of the disease variants (homozygotes) and discriminated between case subjects and control subjects with about 76% accuracy. At least two regions of the TCF4 locus were associated independently with FCD. Alleles in the gene encoding protein tyrosine phosphatase receptor type G (PTPRG) were associated with FCD (P=4.0x10(-7)), but the association did not reach genomewide significance. CONCLUSIONS Genetic variation in TCF4 contributes to the development of FCD. (Funded by the National Eye Institute and others.)
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Affiliation(s)
- Keith H Baratz
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, USA
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18
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Révillion F, Puech C, Rabenoelina F, Chalbos D, Peyrat JP, Freiss G. Expression of the putative tumor suppressor gene PTPN13/PTPL1 is an independent prognostic marker for overall survival in breast cancer. Int J Cancer 2008; 124:638-43. [PMID: 19004008 DOI: 10.1002/ijc.23989] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although it is well established that some protein tyrosine kinases have a prognostic value in breast cancer, the involvement of protein tyrosine phosphatases (PTPs) is poorly substantiated for breast tumors. Three of these enzymes (PTP-gamma, LAR, and PTPL1) are already known to be regulated by estrogens or their antagonists in human breast cancer cells. We used a real-time reverse transcriptase polymerase chain reaction method to test the expression levels of PTP-gamma, LAR and its neuronal isoform, and PTPL1 in a training set of RNA from 59 breast tumors. We sought correlations between levels of these molecular markers, current tumor markers, and survival. We then quantified the expression level of the selected phosphatase in 232 additional samples, resulting in a testing set of 291 breast tumor RNAs from patients with a median follow-up of 6.4 years. The Spearman nonparametric test revealed correlations between PTPL1 expression and differentiation markers. Cox univariate analysis of the overall survival studies demonstrated that PTPL1 is a prognostic factor [risk ratio (RR)=0.45], together with the progesterone receptor (PR) (RR=0.52) and node involvement (RR=1.58). In multivariate analyses, PTPL1 and PR retained their prognostic value (RRs of 0.48 and 0.55, respectively). This study demonstrates for the first time that PTPL1 expression level is an independent prognostic indicator of favorable outcome for patients with breast cancer. In conjunction with our mechanistic studies, this finding identifies PTPL1 as an important regulatory element of human breast tumor aggressiveness and sensitivity to treatments such as antiestrogens and antiaromatase.
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Affiliation(s)
- Françoise Révillion
- Contrôle de la progression des cancers hormono-dépendants, Laboratoire d'Oncologie Moléculaire Humaine, Centre Régional de Lutte contre le Cancer Oscar Lambret, Lille, France
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19
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Ramaswamy B, Majumder S, Roy S, Ghoshal K, Kutay H, Datta J, Younes M, Shapiro CL, Motiwala T, Jacob ST. Estrogen-mediated suppression of the gene encoding protein tyrosine phosphatase PTPRO in human breast cancer: mechanism and role in tamoxifen sensitivity. Mol Endocrinol 2008; 23:176-87. [PMID: 19095770 DOI: 10.1210/me.2008-0211] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We have previously demonstrated the tumor suppressor characteristics of protein tyrosine phosphatase receptor-type O (PTPRO) in leukemia and lung cancer, including its suppression by promoter methylation. Here, we show tumor-specific methylation of the PTPRO CpG island in primary human breast cancer. PTPRO expression was significantly reduced in established breast cancer cell lines MCF-7 and MDA-MB-231 due to promoter methylation compared with its expression in normal human mammary epithelial cells (48R and 184). Further, the silenced gene could be demethylated and reactivated in MCF-7 and MDA-MB-231 cells upon treatment with 5-Azacytidine, a DNA hypomethylating agent. Because PTPRO promoter harbors estrogen-responsive elements and 17beta-estradiol (E2) plays a role in breast carcinogenesis, we examined the effect of E2 and its antagonist tamoxifen on PTPRO expression in human mammary epithelial cells and PTPRO-expressing breast cancer cell line Hs578t. Treatment with E2 significantly curtailed PTPRO expression in 48R and Hs578t cells, which was facilitated by ectopic expression of estrogen receptor (ER)beta but not ERalpha. On the contrary, treatment with tamoxifen increased PTPRO expression. Further, knockdown of ERbeta by small interfering RNA abolished these effects of E2 and tamoxifen. Chromatin immunoprecipitation assay showed association of c-Fos and c-Jun with PTPRO promoter in untreated cells, which was augmented by tamoxifen-mediated recruitment of ERbeta to the promoter. Estradiol treatment resulted in dissociation of c-Fos and c-Jun from the promoter. Ectopic expression of PTPRO in the nonexpressing MCF-7 cells sensitized them to growth-suppressive effects of tamoxifen. These data suggest that estrogen-mediated suppression of PTPRO is probably one of the early events in estrogen-induced tumorigenesis and that expression of PTPRO could facilitate endocrine therapy of breast cancer.
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Affiliation(s)
- Bhuvaneswari Ramaswamy
- Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, Ohio, USA
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20
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Cheung AKL, Lung HL, Hung SC, Law EWL, Cheng Y, Yau WL, Bangarusamy DK, Miller LD, Liu ETB, Shao JY, Kou CW, Chua D, Zabarovsky ER, Tsao SW, Stanbridge EJ, Lung ML. Functional analysis of a cell cycle-associated, tumor-suppressive gene, protein tyrosine phosphatase receptor type G, in nasopharyngeal carcinoma. Cancer Res 2008; 68:8137-45. [PMID: 18829573 DOI: 10.1158/0008-5472.can-08-0904] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Functional studies to identify the potential role of a chromosome 3p14-21 gene, protein tyrosine phosphatase receptor type G (PTPRG), were performed. PTPRG was identified as a candidate tumor suppressor gene (TSG) in nasopharyngeal carcinoma (NPC) by differential gene profiling of tumorigenic and nontumorigenic NPC chromosome 3 microcell hybrids (MCH). Down-regulation of this gene was found in tumor segregants when compared with their corresponding tumor-suppressive MCHs, as well as in NPC cell lines and tumor biopsies. Promoter hypermethylation and loss of heterozygosity were found to be important mechanisms contributing to PTPRG silencing. PTPRG overexpression in NPC cell lines induces growth suppression and reduced anchorage-independent growth in vitro. This is the first study to use a tetracycline-responsive vector expression system to study PTPRG stable transfectants. Results indicate its ability to induce significant tumor growth suppression in nude mice under conditions activating transgene expression. These studies now provide functional evidence indicating critical interactions of PTPRG in the extracellular matrix milieu induce cell arrest and changes in cell cycle status. This is associated with inhibition of pRB phosphorylation through down-regulation of cyclin D1. These novel findings enhance our current understanding of how PTPRG may contribute to tumorigenesis.
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Affiliation(s)
- Arthur Kwok Leung Cheung
- Department of Biology and Center for Cancer Research, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, People's Republic of China
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21
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Kotamraju S, Williams CL, Willams CL, Kalyanaraman B. Statin-induced breast cancer cell death: role of inducible nitric oxide and arginase-dependent pathways. Cancer Res 2007; 67:7386-94. [PMID: 17671209 DOI: 10.1158/0008-5472.can-07-0993] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Statins are widely used cholesterol-lowering drugs that selectively inhibit the enzyme 3-hydroxy-3-methylglutaryl CoA reductase, leading to decreased cholesterol biosynthesis. Emerging data indicate that statins stimulate apoptotic cell death in several types of proliferating tumor cells, including breast cancer cells, which is independent of its cholesterol-lowering property. The objective here was to elucidate the molecular mechanism(s) by which statins induce breast cancer cell death. Fluvastatin and simvastatin (5-10 mumol/L) treatment enhanced the caspase-3-like activity and DNA fragmentation in MCF-7 cells, and significantly inhibited the proliferation of MCF-7 cells but not MCF-10 cells (noncancerous epithelial cells). Statin-induced cytotoxic effects were reversed by mevalonate, an immediate metabolic product of the acetyl CoA/3-hydroxy-3-methylglutaryl CoA reductase reaction. Both simvastatin and fluvastatin enhanced nitric oxide ((.)NO) levels which were inhibited by mevalonate. Statin-induced (.)NO and tumor cell cytotoxicity were inhibited by 1400W, a more specific inhibitor of inducible nitric oxide synthase (iNOS or NOS II). Both fluvastatin and simvastatin increased iNOS mRNA and protein expression. Stimulation of iNOS by statins via inhibition of geranylgeranylation by GGTI-298, but not via inhibition of farnesylation by FTI-277, enhanced the proapoptotic effects of statins in MCF-7 cells. Statin-mediated antiproliferative and proapoptotic effects were exacerbated by sepiapterin, a precursor of tetrahydrobiopterin, an essential cofactor of (.)NO biosynthesis by NOS. We conclude that iNOS-mediated (.)NO is responsible in part for the proapoptotic, tumoricidal, and antiproliferative effects of statins in MCF-7 cells.
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Affiliation(s)
- Srigiridhar Kotamraju
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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Vezzalini M, Mombello A, Menestrina F, Mafficini A, Della Peruta M, van Niekerk C, Barbareschi M, Scarpa A, Sorio C. Expression of transmembrane protein tyrosine phosphatase gamma (PTPgamma) in normal and neoplastic human tissues. Histopathology 2007; 50:615-28. [PMID: 17394498 DOI: 10.1111/j.1365-2559.2007.02661.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS To establish the conditions for protein tyrosine phosphatase gamma (PTPgamma) detection in paraffin tissues using two antibodies raised against its NH(2)- (anti-P4) and COOH-termini (gammaTL1); to analyse its expression in normal tissues and to perform an initial screening of neoplastic tissues. METHODS AND RESULTS Membranous and/or cytoplasmic PTPgamma expression was detected in the majority of epithelial cell types and in endocrine cells, with the highest expression in adrenal medulla, endocrine cells of the gastrointestinal tract and pancreatic islets. Both antibodies stained the thyroid follicular epithelium, but only anti-P4 antibody stained the colloid matrix, suggesting shedding/secretion of the PTPgamma extracellular domain. Marked loss of PTPgamma immunoreactivity was detected in subsets of ovarian (21%), breast (56%) and lung (80%) neoplasms. Conversely, cytoplasmic positivity was found in 37% of lymphomas, mainly of high-grade histotypes, while normal lymphocytes were negative. Brain tissue showed PTPgamma expression in a few neuronal and glial elements and PTPgamma was overexpressed in the majority of high-grade astrocytomas. CONCLUSIONS We have analysed PTPgamma expression in archival paraffin-embedded tissues for the first time, demonstrating particularly high expression in endocrine cells and both down- and up-regulation in neoplasia, the latter possibly reflecting the undifferentiated state of the neoplastic cells, suggesting a complex role for this phosphatase.
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Affiliation(s)
- M Vezzalini
- Department of Pathology, University of Verona, Verona, Italy
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Affiliation(s)
- Tasneem Motiwala
- Department of Molecular and Cellular Biochemistry, The Ohio State University, College of Medicine, Columbus, Ohio 43210, USA
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