Activation of RHOA transcription in epithelial tumors may be caused by gene amplification and/or demethylation of the promoter region

Abstract

RHOA protein, a member of small GTPases family, is implicated in cell morphogenesis, adhesion, and in cell cycle regulation. RHOA gene (3p21.31) exhibits cell transformation activity, and therefore gene is considered as a potential oncogene. The aim of this study was to investigate RHOA transcription and copy number changes in three epithelial tumors (breast, renal cell and epithelial ovarian carcinomas, 45 tumor/normal pairs altogether). EII, HhaI, AciI n Bsh1236I). Hypomethylation of the RHOA promoter region in tumor DNA was observed two times more frequently than increased methylation. Moreover, all (15) cancer cases with hypomethylation of the RHOA gene showed a 2-10 fold increased expression of RHOA. It was concluded that gene copy multiplication and demethylation of the RHOA promoter region can contribute to transcription activation of this gene in epithelial tumors.