Epigenetic analysis leads to identification of HNF1B as a subtype-specific susceptibility gene for ovarian cancer (original) (raw)
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Oncotarget, 2015
Two independent regions within HNF1B are consistently identified in prostate and ovarian cancer genome-wide association studies (GWAS); their functional roles are unclear. We link prostate cancer (PC) risk SNPs rs11649743 and rs3760511 with elevated HNF1B gene expression and allele-specific epigenetic silencing, and outline a mechanism by which common risk variants could effect functional changes that increase disease risk: functional assays suggest that HNF1B is a pro-differentiation factor that suppresses epithelial-to-mesenchymal transition (EMT) in unmethylated, healthy tissues. This tumor-suppressor activity is lost when HNF1B is silenced by promoter methylation in the progression to PC. Epigenetic inactivation of HNF1B in ovarian cancer also associates with known risk SNPs, with a similar impact on EMT. This represents one of the first comprehensive studies into the pleiotropic role of a GWAS-associated transcription factor across distinct cancer types, and is the first to describe a conserved role for a multi-cancer genetic risk factor.
Epigenetic determinants of ovarian clear cell carcinoma biology
International Journal of Cancer, 2014
Targeted approaches have revealed frequent epigenetic alterations in ovarian cancer, but the scope and relation of these changes to histologic subtype of disease is unclear. Genome-wide methylation and expression data for 14 clear cell carcinoma (CCC), 32 non-CCC and four corresponding normal cell lines were generated to determine how methylation profiles differ between cells of different histological derivations of ovarian cancer. Consensus clustering showed that CCC is epigenetically distinct. Inverse relationships between expression and methylation in CCC were identified, suggesting functional regulation by methylation, and included 22 hypomethylated (UM) genes and 276 hypermethylated (HM) genes. Categorical and pathway analyses indicated that the CCC-specific UM genes were involved in response to stress and many contain hepatocyte nuclear factor (HNF) 1-binding sites, while the CCC-specific HM genes included members of the estrogen receptor alpha (ERalpha) network and genes involved in tumor development. We independently validated the methylation status of 17 of these pathwayspecific genes, and confirmed increased expression of HNF1 network genes and repression of ERalpha pathway genes in CCC cell lines and primary cancer tissues relative to non-CCC specimens. Treatment of three CCC cell lines with the demethylating agent Decitabine significantly induced expression for all five genes analyzed. Coordinate changes in pathway expression were confirmed using two primary ovarian cancer datasets (p < 0.0001 for both). Our results suggest that methylation regulates specific pathways and biological functions in CCC, with hypomethylation influencing the characteristic biology of the disease while hypermethylation contributes to the carcinogenic process.
BMC Medical Genomics, 2014
Background: Both genetic and epigenetic factors influence the development and progression of epithelial ovarian cancer (EOC). However, there is an incomplete understanding of the interrelationship between these factors and the extent to which they interact to impact disease risk. In the present study, we aimed to gain insight into this relationship by identifying DNA methylation marks that are candidate mediators of ovarian cancer genetic risk.
International journal of molecular sciences, 2017
DNA methylation is well-known to be associated with ovarian cancer (OC) and has great potential to serve as a biomarker in monitoring response to therapy and for disease screening. The purpose of this study was to investigate methylation of HNF1B and GATA4 and correlate detected methylation with clinicopathological characteristic of OC patients. The study group consisted of 64 patients with OC and 35 control patients. To determine the most important sites of HNF1B and GATA4, we used next-generation sequencing. For further confirmation of detected methylation of selected regions, we used high-resolution melting analysis and methylation-specific real-time polymerase chain reaction (PCR). Selected regions of HNF1B and GATA4 were completely methylation free in all control samples, whereas methylation-positive pattern was observed in 32.8% (HNF1B) and 45.3% (GATA4) of OC samples. Evaluating both genes together, we were able to detect methylation in 65.6% of OC patients. We observed a sta...
Promoter Methylation status of HIN-1 associated with outcomes of ovarian clear cell adenocarcinoma
Molecular Cancer, 2012
Background This study is to analyze promoter methylation of various tumor suppressor genes in different types of ovarian carcinoma and to identify potential therapeutic targets of ovarian clear cell adenocarcinoma (OCCA). Materials and methods The promoter methylation statuses of 40 genes in primary ovarian carcinomas including 47 clear- and 63 non-clear-cell type tissues, 6 OCCA cell lines, 29 benign ovarian endometriotic cysts, and 31 normal controls were analyzed by methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA). The MS-MLPA results were correlated with clinicopathological features and outcomes of 47 OCCA patients. Functions of the target genes were further explored by Western Blot Analysis, apoptosis assay, and caspase-3/7 activity analysis. Results Frequencies of methylated RASSF1A, CDH13, CACNA1A, HIN-1, and sFRP5 genes in OCCA tissues were significantly higher than those in non-OCCA cancerous tissues and benign endometriotic cysts. The expecte...
DNA Methylation Profiles of Ovarian Epithelial Carcinoma Tumors and Cell Lines
PLoS ONE, 2010
Background: Epithelial ovarian carcinoma is a significant cause of cancer mortality in women worldwide and in the United States. Epithelial ovarian cancer comprises several histological subtypes, each with distinct clinical and molecular characteristics. The natural history of this heterogeneous disease, including the cell types of origin, is poorly understood. This study applied recently developed methods for high-throughput DNA methylation profiling to characterize ovarian cancer cell lines and tumors, including representatives of three major histologies.
DNA methylation profiles in ovarian cancer: Implication in diagnosis and therapy (Review)
Molecular Medicine Reports, 2014
Genetic alterations alone cannot account for the complexity of ovarian cancer. The potential reversibility of epigenetic mechanisms makes them attractive candidates for the prevention and/or treatment of ovarian carcinoma. Detection of the epigenetic signature of each cancer cell may be useful in the identification of candidate biomarkers for disease detection, classification and monitoring and may also facilitate personalized cancer treatment. In ovarian cancer, in addition to other non-gynaecological cancers, two opposite epigenetic phenomena occur. The first involves an overall global decrease in DNA methylation of heterochromatin leading to demethylation of several oncogenes, while the second involves specific CpG island hypermethylation associated with the promoters of tumor suppressor genes. Early studies focused on the methylation patterns of single genes associated with tumorigenesis. However, newer genome-wide methods have identified a group of genes whose regulation is altered by DNA methylation during ovarian cancer progression.
Epigenetics : official journal of the DNA Methylation Society, 2014
Diagnosis and treatment of epithelial ovarian cancer is challenging due to the poor understanding of the pathogenesis of the disease. Our aim was to investigate epigenetic mechanisms in ovarian tumorigenesis and, especially, whether tumors with different histological subtypes or hereditary background (Lynch syndrome) exhibit differential susceptibility to epigenetic inactivation of growth regulatory genes. Gene candidates for epigenetic regulation were identified from the literature and by expression profiling of ovarian and endometrial cancer cell lines treated with demethylating agents. Thirteen genes were chosen for methylation-specific multiplex ligation-dependent probe amplification assays on 104 (85 sporadic and 19 Lynch syndrome-associated) ovarian carcinomas. Increased methylation (i.e., hypermethylation) of variable degree was characteristic of ovarian carcinomas relative to the corresponding normal tissues, and hypermethylation was consistently more prominent in non-serous...
An epigenetic marker panel for screening and prognostic prediction of ovarian cancer
International Journal of Cancer, 2009
Aberrant CpG island hypermethylation is a common finding of cancers, which might be detectable in the tissue or serum of affected patients. We analyzed DNA methylation by methylation-specific polymerase chain reaction of 7 genes, which included secreted frizzled receptor proteins 1, 2, 4, 5 (SFRP1, 2, 4, 5), SRY-box 1 (SOX1), paired box gene 1 (PAX1) and LIM homeobox transcription factor 1, alpha (LMX1A) in primary tumor samples from 126 patients with ovarian cancer, 75 with a benign tumor and 14 with borderline malignancy of an ovarian tumor, and in the serum from 26 patients with ovarian cancer and 20 with a benign tumor. Six of 7 genes had higher methylation rates in patients with ovarian cancer than in borderline malignancy or benign tumor (p < 0.001). The methylation of SFRP1, SFRP2, SOX1 and LMX1A genes correlated with recurrence and overall survival of ovarian cancer patients. Combining the data for SFRP1, SFRP2 and SOX1 genes gave a relative risk for recurrence of 3.19 (p = 0.013) in patients with at least one gene methylation, and combining the data for SFRP1, SOX1 and LMX1A gave an RR for cancer-related death of 6.09 (p = 0.010). Methylation analysis of tissues and serum revealed a significant correlation (kappa values, 0.332–0.598) and a highly sensitivity and specificity rates (73.08 and 75%) as a screening marker. In conclusion, promoter hypermethylation of specific genes in critical pathways is common in ovarian cancer and has potential as a prognostic factor and a promising serum marker for early screening. © 2008 Wiley-Liss, Inc.
Epigenetic and genetic dispositions of ovarian carcinomas
Oncoscience, 2014
Ovarian clear cell carcinoma has unique clinical characteristics with slow growth and a stress-resistant phenotype that is epigenetically induced during cancer progression in an inflammatory microenvironment. We refer to this as an epigenetic disposition, which is frequently associated with unique biomolecular features including prominent alterations in methylation, microsatellite instability and ARID1A mutations. This characteristic methylation profile also affects glucose metabolism, commonly known as the Warburg effect. In contrast, high-grade ovarian serous adenocarcinoma has a genetic disposition that is accompanied by rapid growth, TP53 mutations and chromosomal instability. The concept of epigenetic and genetic dispositions is applicable to various malignancies, including gastric and colorectal cancers. These disposition classifications are based on fundamental characteristics of malignancies and may provide a new vantage point for development of individualized therapies.