A novel genome-based approach correlates TMPRSS3 overexpression in ovarian cancer with DNA hypomethylation

• Published in: Gynecologic oncology 2012-06, Vol.125 (3), p.720-726
• Main Authors: Guerrero, Kether, Wang, Zhiqiang, Bachvarova, Magdalena, Gregoire, Jean, Renaud, Marie-Claude, Plante, Marie, Bachvarov, Dimcho
• Format: Article
• Language: English
• Subjects: Base Sequence; Carcinoma, Ovarian Epithelial; Cell Line, Tumor; CpG Islands; DNA hypomethylation; DNA Methylation; Epithelial ovarian cancer; Female; Gene expression analysis; Gene Expression Profiling; Genome, Human; Hematology, Oncology and Palliative Medicine; Humans; Membrane Proteins - biosynthesis; Membrane Proteins - genetics; Molecular Sequence Data; Neoplasm Proteins - biosynthesis; Neoplasm Proteins - genetics; Neoplasms, Glandular and Epithelial - enzymology; Neoplasms, Glandular and Epithelial - genetics; Obstetrics and Gynecology; Ovarian Neoplasms - enzymology; Ovarian Neoplasms - genetics; Promoter Regions, Genetic; S-adenosyl-l-methionine; S-Adenosylmethionine - pharmacology; Serine Endopeptidases - biosynthesis; Serine Endopeptidases - genetics; TMPRSS3
• ISSN: 0090-8258; 1095-6859
• DOI: 10.1016/j.ygyno.2012.03.026

Abstract Objective In an attempt to analyze more profoundly aberrant DNA hypomethylation in epithelial ovarian cancer (EOC), we applied a novel genome-based approach which includes expression profiling following pharmacologic stimulation of DNA methylation with the methyl donor S-adenosyl- l -methionine (SAM). Methods Four different EOC cell lines (OVCAR3, SKOV3, TOV21 and TOV112) were treated with SAM, and gene expression profiling was performed in SAM-treated and control EOC cells. Genes, downregulated upon SAM treatment were considered as potentially hypomethylated in EOC. DNA hypomethylation was independently validated in ovarian tumor and control tissues by bisulfite sequencing PCR (BSP). Results Among the genes identified, one of particular interest was the type II serine protease TMPRSS3 gene variants A and D (TMPRSS3-A/D), previously recognized as overexpressed in EOC and representing potential EOC therapeutic targets. Consecutive BSP analysis demonstrated that the common putative promoter region of the TMPRSS3-A/D gene variants was significantly hypomethylated in high-grade serous EOC tumors, compared to low-malignant potential ovarian tumors and normal ovarian tissue. Conclusions Our data imply that TMPRSS3-A/D overexpression in EOC is probably due to hypomethylation of their control region thus indicating that TMPRSS3-A/D variants could also represent novel molecular targets for epigenetic therapy of late stages of the disease. Our results also suggest that the frequently observed upregulation of different members of the type II serine proteases gene family in advanced cancer could be due to aberrant DNA hypomethylation. Furthermore, our study introduces a promising discovery approach that could be used for the identification of hypomethylated genes in different experimental cell models.