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Sharma A, Albahrani M, Zhang W, Kufel CN, James SR, Odunsi K, Klinkebiel D, Karpf AR. Epigenetic activation of POTE genes in ovarian cancer. Epigenetics 2019; 14:185-197. [PMID: 30764732 DOI: 10.1080/15592294.2019.1581590] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
The POTE gene family consists of 14 homologous genes localized to autosomal pericentromeres, and a sub-set of POTEs are cancer-testis antigen (CTA) genes. POTEs are over-expressed in epithelial ovarian cancer (EOC), including the high-grade serous subtype (HGSC), and expression of individual POTEs correlates with chemoresistance and reduced survival in HGSC. The mechanisms driving POTE overexpression in EOC and other cancers is unknown. Here, we investigated the role of epigenetics in regulating POTE expression, with a focus on DNA hypomethylation. Consistent with their pericentromeric localization, Pan-POTE expression in EOC correlated with expression of the pericentromeric repeat NBL2, which was not the case for non-pericentromeric CTAs. POTE genomic regions contain LINE-1 (L1) sequences, and Pan-POTE expression correlated with both global and POTE-specific L1 hypomethylation in EOC. Analysis of individual POTEs using RNA-seq and DNA methylome data from fallopian tube epithelia (FTE) and HGSC revealed that POTEs C, E, and F have increased expression in HGSC in conjunction with DNA hypomethylation at 5' promoter or enhancer regions. Moreover, POTEs C/E/F showed additional increased expression in recurrent HGSC in conjunction with 5' hypomethylation, using patient-matched samples. Experiments using decitabine treatment and DNMT knockout cell lines verified a functional contribution of DNA methylation to POTE repression, and epigenetic drug combinations targeting histone deacetylases (HDACs) and histone methyltransferases (HMTs) in combination with decitabine further increased POTE expression. In summary, several alterations of the cancer epigenome, including pericentromeric activation, global and locus-specific L1 hypomethylation, and locus-specific 5' CpG hypomethylation, converge to promote POTE expression in ovarian cancer.
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Affiliation(s)
- Ashok Sharma
- a Eppley Institute , University of Nebraska Medical Center , Omaha , NE , USA.,b Fred & Pamela Buffett Cancer Center , University of Nebraska Medical Center , Omaha , NE , USA
| | - Mustafa Albahrani
- a Eppley Institute , University of Nebraska Medical Center , Omaha , NE , USA.,b Fred & Pamela Buffett Cancer Center , University of Nebraska Medical Center , Omaha , NE , USA
| | - Wa Zhang
- a Eppley Institute , University of Nebraska Medical Center , Omaha , NE , USA.,b Fred & Pamela Buffett Cancer Center , University of Nebraska Medical Center , Omaha , NE , USA
| | - Christina N Kufel
- c Department of Pharmacology and Therapeutics , Roswell Park Comprehensive Cancer Center , Buffalo , NY , USA
| | - Smitha R James
- c Department of Pharmacology and Therapeutics , Roswell Park Comprehensive Cancer Center , Buffalo , NY , USA
| | - Kunle Odunsi
- d Department of Immunology , Roswell Park Comprehensive Cancer Center , Buffalo , NY , USA.,e Department of Gynecologic Oncology , Roswell Park Comprehensive Cancer Center , Buffalo , NY , USA.,f Center for Immunotherapy , Roswell Park Comprehensive Cancer Center , Buffalo , NY , USA
| | - David Klinkebiel
- b Fred & Pamela Buffett Cancer Center , University of Nebraska Medical Center , Omaha , NE , USA.,g Department of Biochemistry and Molecular Biology , University of Nebraska Medical Center , Omaha , NE , USA
| | - Adam R Karpf
- a Eppley Institute , University of Nebraska Medical Center , Omaha , NE , USA.,b Fred & Pamela Buffett Cancer Center , University of Nebraska Medical Center , Omaha , NE , USA.,c Department of Pharmacology and Therapeutics , Roswell Park Comprehensive Cancer Center , Buffalo , NY , USA
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Wang L, Li M, Zhan Y, Ban X, Zeng T, Zhu Y, Yun J, Guan XY, Li Y. Down-regulation of POTEG predicts poor prognosis in esophageal squamous cell carcinoma patients. Mol Carcinog 2018; 57:886-895. [PMID: 29566278 PMCID: PMC6001627 DOI: 10.1002/mc.22809] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/08/2018] [Accepted: 03/20/2018] [Indexed: 12/18/2022]
Abstract
POTE ankyrin domain family, member G (poteg) belongs to POTE family. The POTE family is composed of many proteins which are very closely related and expressed in prostate, ovary, testis, and placenta. Some POTE paralogs are related with some cancers. Here we showed that down‐regulation of POTEG was detected in about 60% primary esophageal squamous cell carcinoma (ESCC) tumor tissues. Clinical association studies determined that POTEG down‐regulation was significantly correlated with tumor differentiation, lymph nodes metastasis and TNM staging. Kaplan‐Meier analysis determined that POTEG down‐regulation was associated with poorer clinical outcomes of ESCC patients (P = 0.026). Functional studies showed that POTEG overexpression could suppress tumor cell growth and metastasis capacity in vitro and in vivo. Molecular analyses revealed that POTEG downregulated CDKs, leading to subsequent inhibition of Rb phosphorylation, and consequently arrested Cell Cycle at G1/S Checkpoint. POTEG overexpression induced apoptosis by activating caspases and PARP, and regulating canonical mitochondrial apoptotic pathways. On the other side, POTEG inhibited epithelial‐mesenchymal transition and suppressed tumor cell metastasis. In conclusion, our study reveals a functionally important control mechanism of POTEG in esophageal cancer pathogenesis, suggesting potential use in the ESCC intervention and therapeutic strategies.
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Affiliation(s)
- Ling Wang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China.,Guangdong Esophageal Cancer Institute, Guangzhou, P.R. China
| | - Mengqing Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Yuting Zhan
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Xiaojiao Ban
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Tingting Zeng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Yinghui Zhu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Jingping Yun
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
| | - Xin-Yuan Guan
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China.,Department of Clinical Oncology, The University of Hong Kong, Hong Kong, P.R. China
| | - Yan Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, P.R. China
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Wang Q, Li X, Ren S, Cheng N, Zhao M, Zhang Y, Li J, Cai W, Zhao C, Cao W, Zhou C. Serum levels of the cancer-testis antigen POTEE and its clinical significance in non-small-cell lung cancer. PLoS One 2015; 10:e0122792. [PMID: 25860145 PMCID: PMC4393100 DOI: 10.1371/journal.pone.0122792] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 02/15/2015] [Indexed: 02/01/2023] Open
Abstract
Background POTEE (POTE ankyrin domain family, member E) is a newly identified cancer-testis antigen that has been found to be expressed in a wide variety of human cancers including cancers of the colon, prostate, lung, breast, ovary, and pancreas. Aim To measure the serum levels of POTEE in patients with non-small-cell lung cancer (NSCLC) and to explore the clinical significance of POTEE in NSCLC. Patients and Methods 104 NSCLC patients, 66 benign lung disease patients and 80 healthy volunteers were enrolled in this study from May 2013 to February 2014. Serum POTEE levels were measured using enzyme-linked immunosorbent assay (ELISA). Numerical variables were recorded as means ± standard deviation (SD) and analyzed by independent t tests. Categorical variables were calculated as rates and were analyzed using a χ2 test or Fisher’s exact test. Survival curves were estimated and compared using the Kaplan-Meier method and log-rank tests. Results Serum POTEE levels were significantly higher in NSCLC patients than in benign lung disease patients and healthy controls (mean ± SD [pg/ml], 324.38± 13.84 vs. 156.93 ± 17.38 and 139.09 ± 15.80, P<0.001) and were significantly correlated with TNM stage. Survival analysis revealed that patients with low serum POTEE had longer progression-free survival (PFS) than those with high serum POTEE (P=0.021). Cox multivariate analysis indicated that POTEE was an independent prognostic factor of progression-free survival (P =0.009, hazard ratio, 2.440). Conclusions Serum POTEE level in NSCLC patients is associated with TNM stage and is a potential prognostic factor.
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Affiliation(s)
- Qi Wang
- Department of Lung Cancer and Immunology, Shanghai Pulmonary Hospital, Tongji University, Tongji University Medical School Cancer Institute, Shanghai, People’s Republic of China
| | - Xuefei Li
- Department of Lung Cancer and Immunology, Shanghai Pulmonary Hospital, Tongji University, Tongji University Medical School Cancer Institute, Shanghai, People’s Republic of China
| | - Shengxiang Ren
- Department of Lung Cancer and Immunology, Shanghai Pulmonary Hospital, Tongji University, Tongji University Medical School Cancer Institute, Shanghai, People’s Republic of China
| | - Ningning Cheng
- Department of Lung Cancer and Immunology, Shanghai Pulmonary Hospital, Tongji University, Tongji University Medical School Cancer Institute, Shanghai, People’s Republic of China
| | - Mingchuan Zhao
- Department of Lung Cancer and Immunology, Shanghai Pulmonary Hospital, Tongji University, Tongji University Medical School Cancer Institute, Shanghai, People’s Republic of China
| | - Yishi Zhang
- Department of Lung Cancer and Immunology, Shanghai Pulmonary Hospital, Tongji University, Tongji University Medical School Cancer Institute, Shanghai, People’s Republic of China
| | - Jiayu Li
- Department of Lung Cancer and Immunology, Shanghai Pulmonary Hospital, Tongji University, Tongji University Medical School Cancer Institute, Shanghai, People’s Republic of China
| | - Weijing Cai
- Department of Lung Cancer and Immunology, Shanghai Pulmonary Hospital, Tongji University, Tongji University Medical School Cancer Institute, Shanghai, People’s Republic of China
| | - Chao Zhao
- Department of Lung Cancer and Immunology, Shanghai Pulmonary Hospital, Tongji University, Tongji University Medical School Cancer Institute, Shanghai, People’s Republic of China
| | - Wa Cao
- Department of Lung Cancer and Immunology, Shanghai Pulmonary Hospital, Tongji University, Tongji University Medical School Cancer Institute, Shanghai, People’s Republic of China
| | - Caicun Zhou
- Department of Lung Cancer and Immunology, Shanghai Pulmonary Hospital, Tongji University, Tongji University Medical School Cancer Institute, Shanghai, People’s Republic of China
- * E-mail:
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Liu XF, Bera TK, Liu LJ, Pastan I. A primate-specific POTE-actin fusion protein plays a role in apoptosis. Apoptosis 2010; 14:1237-44. [PMID: 19669888 DOI: 10.1007/s10495-009-0392-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The primate-specific gene family, POTE, is expressed in many cancers but only in a limited number of normal tissues (testis, ovary, prostate). The 13 POTE paralogs are dispersed among 8 human chromosomes. They evolved by gene duplication and remodeling from an ancestral gene, Ankrd26, recently implicated in controlling body size and obesity. In addition, several POTE paralogs are fused to an actin retrogene producing POTE-actin fusion proteins. The biological function of the POTE genes is unknown, but their high expression in primary spermatocytes, some of which are undergoing apoptosis, suggests a role in inducing programmed cell death. We have chosen Hela cells as a model to study POTE function in human cancer, and have identified POTE-2alpha-actin as the major transcript and the protein it encodes in Hela cells. Transfection experiments show that both POTE-2alpha-actin and POTE-2gammaC are localized to actin filaments close to the inner plasma membrane. Transient expression of POTE-2alpha-actin or POTE-2gammaC induces apoptosis in Hela cells. Using wild-type and mutant mouse embryo cells, we find apoptosis induced by over-expression of POTE-2gammaC is decreased in Bak ( -/- ) or Bak ( -/- ) Bax ( -/- ) cells indicating POTE is acting through a mitochondrial pathway. Endogenous POTE-actin protein levels but not RNA levels increased in a time dependent manner by stimulation of death receptors with their cognate ligands. Our data indicates that the POTE gene family encodes a new family of proapoptotic proteins.
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Affiliation(s)
- Xiu Fen Liu
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4264, USA
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Tandem repeats modify the structure of human genes hosted in segmental duplications. Genome Biol 2009; 10:R137. [PMID: 19954527 PMCID: PMC2812944 DOI: 10.1186/gb-2009-10-12-r137] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 10/08/2009] [Accepted: 12/02/2009] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Recently duplicated genes are often subject to genomic rearrangements that can lead to the development of novel gene structures. Here we specifically investigated the effect of variations in internal tandem repeats (ITRs) on the gene structure of human paralogs located in segmental duplications. RESULTS We found that around 7% of the primate-specific genes located within duplicated regions of the genome contain variable tandem repeats. These genes are members of large groups of recently duplicated paralogs that are often polymorphic in the human population. Half of the identified ITRs occur within coding exons and may be either kept or spliced out from the mature transcript. When ITRs reside within exons, they encode variable amino acid repeats. When located at exon-intron boundaries, ITRs can generate alternative splicing patterns through the formation of novel introns. CONCLUSIONS Our study shows that variation in the number of ITRs impacts on recently duplicated genes by modifying their coding sequence, splicing pattern, and tissue expression. The resulting effect is the production of a variety of primate-specific proteins, which mostly differ in number and sequence of amino acid repeats.
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Sethi S, Adams W, Pollock J, Witt-Enderby PA. C-terminal domains within human MT1 and MT2 melatonin receptors are involved in internalization processes. J Pineal Res 2008; 45:212-8. [PMID: 18341518 DOI: 10.1111/j.1600-079x.2008.00579.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Melatonin, a molecule implicated in a variety of diseases, including cancer, often exerts its effects through G-protein-coupled melatonin receptors, MT(1) and MT(2). In this study, we sought to understand further the domains involved in the function and desensitization patterns of these receptors through site-directed mutagenesis. Two mutations were constructed in the cytoplasmic C-terminal tail of each receptor subtype: (i) a cysteine residue in the C-terminal tail was mutated to alanine, thus removing a putative palmitoylation site, and a site possibly required for normal receptor function (MT(1)C7.72A and MT(2)C7.77A) and (ii) the C-terminal tail in the MT(1) and MT(2) receptors was truncated, removing the putative phosphorylation and beta-arrestin binding sites (MT(1)Y7.64 and MT(2)Y7.64). These mutations did not alter the affinity of 2-[(125)I]-iodomelatonin binding to the MT(1) or MT(2) receptors. Using confocal microscopy, it was determined that the putative palmitoylation site (cysteine residue) did not play a role in receptor internalization; however, this residue was essential for receptor function, as determined by 3',5'-cyclic adenosine monophosphate (cAMP) accumulation assays. Truncation of the C-terminal tail of both receptors (MT(1)Y7.64 and MT(2)Y7.64) inhibited internalization as well as the cAMP response, suggesting the importance of the C-terminal tail in these receptor functions.
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MESH Headings
- Animals
- Arrestins/metabolism
- Binding Sites/genetics
- COS Cells
- Chlorocebus aethiops
- Cyclic AMP/metabolism
- Endocytosis/physiology
- Humans
- Melatonin/metabolism
- Microscopy, Confocal
- Models, Biological
- Mutation
- Receptor, Melatonin, MT1/genetics
- Receptor, Melatonin, MT1/physiology
- Receptor, Melatonin, MT2/genetics
- Receptor, Melatonin, MT2/physiology
- beta-Arrestins
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Affiliation(s)
- Shalini Sethi
- Division of Pharmaceutical Sciences, School of Pharmacy, Bayer School of Natural and Environmental Sciences, Duquesne University, Pittsburgh, PA 15282, USA
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Ise T, Das S, Nagata S, Maeda H, Lee Y, Onda M, Anver MR, Bera TK, Pastan I. Expression of POTE protein in human testis detected by novel monoclonal antibodies. Biochem Biophys Res Commun 2007; 365:603-8. [PMID: 17996727 DOI: 10.1016/j.bbrc.2007.10.195] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Accepted: 10/27/2007] [Indexed: 10/22/2022]
Abstract
The POTE gene family is composed of 13 highly homologous paralogs preferentially expressed in prostate, ovary, testis, and placenta. We produced 10 monoclonal antibodies (MAbs) against three representative POTE paralogs: POTE-21, POTE-2gammaC, and POTE-22. One reacted with all three paralogs, six MAbs reacted with POTE-2gammaC and POTE-22, and three MAbs were specific to POTE-21. Epitopes of all 10 MAbs were located in the cysteine-rich repeats (CRRs) motifs located at the N-terminus of each POTE paralog. Testing the reactivity of each MAb with 12 different CRRs revealed slight differences among the antigenic determinants, which accounts for differences in cross-reactivity. Using MAbs HP8 and PG5 we were able to detect a POTE-actin fusion protein in human testis by immunoprecipitation followed by Western blotting. By immunohistochemistry we demonstrated that the POTE protein is expressed in primary spermatocytes, implying a role in spermatogenesis.
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Affiliation(s)
- Tomoko Ise
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4264, USA
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