Estrogen receptor b1 exerts antitum oral effects on SK-OV-3 ovarian cancer cells

Estrogen receptor (ER) b1 and its splice variants are expressed both in ovary and ovarian cancer. We studied the role of ERb1 and two of its splice variants in regulation of gene expression, cellular proliferation, apoptosis, and migration of an ovarian cancer cell line. In this study, we transfected SK-OV-3 ovarian cancer cells with vectors coding for ERb1 or its splice variants ERb-d125 and ERb-d1256, and tested their response to estrogen and tamoxifen in comparison with the untransfected cells. Heterologous expression of ERb1, but not of the exon-deleted ERb variants resulted in notably slower cell growth of SK-OV-3 ovarian cancer cells, an effect Journal of Endocrinology (2007) 193, 421–433 0022–0795/07/0193–421 q 2007 Society for Endocrinology Printed in Great accompanied by more than tenfold increase of cyclindependent kinase inhibitor p21(WAF1) transcript levels and a significant reduction of cyclin A2 mRNA levels. SK-OV-3 cells stably overexpressing ERb1 ligand independently also exhibited an increased apoptosis rate and a significantly decreased motility, an effect accompanied by upregulation of fibulin 1c. Our data demonstrate that ERb1, but not the exon-deleted isoforms tested exerts multiple antitumoral effects on SK-OV-3 ovarian cancer cells even in the absence of estradiol or functional ERa. Journal of Endocrinology (2007) 193, 421–433