Zusammenfassung
BackgroundEstrogen receptor beta (ER beta) has been repeatedly suggested to play important roles in hormone-dependent cancer like in tumors of the breast, ovary or prostate. In this study, we intended to further elucidate its role in endometrial cancer.MethodsFor this purpose, we knocked down ER beta expression in two endometrial cancer cell lines, the ER alpha-negative/ER beta-positive line ...
Zusammenfassung
BackgroundEstrogen receptor beta (ER beta) has been repeatedly suggested to play important roles in hormone-dependent cancer like in tumors of the breast, ovary or prostate. In this study, we intended to further elucidate its role in endometrial cancer.MethodsFor this purpose, we knocked down ER beta expression in two endometrial cancer cell lines, the ER alpha-negative/ER beta-positive line HEC-1A and the ER alpha/beta-positive cell line RL95/2, by means of siRNA transfection. Cell proliferation after transfection was assessed using the fluorescent CTB Assay (Promega). In order to elucidate possible molecular mechanisms which might underlie the effect on proliferation, we performed transcriptome analyses by means of human Affymetrix Human Gene Chip 2.0. Additionally, we treated the employed cell lines with different ER beta modulators to examine their effect on proliferation.ResultssiRNA-mediated knockdown of ER beta significantly increased proliferation of both endometrial cancer cell lines. In HEC-1A cells, proliferation was significantly increased 4, 5 and 6days after transfection, with a maximum of about 1.7-fold (p<0.05) on day 6. Endometrial RL95/2 cells with an ER beta knockdown exhibited a clearly enhanced proliferation on day 3 and days 4 to 8, when even 2.4-fold higher numbers of viable cells were detected (p<0.01). Transcriptome analysis revealed that this was accompanied by increased expression of several genes being known to be upregulated in cancer, including proliferation-associated genes and oncogenes, and by repression of genes associated with differentiation, apoptosis or growth inhibition. Corroborating the observed knockdown effects, treatment with the ER beta antagonists PHTTP and (R, R) THC was also able to induce proliferation of both cell lines.ConclusionsOur data clearly support the putative role of ER beta as tumor suppressor in endometrium as previously suggested in studies on other tissues and encourage further studies to find out to what extent this molecule might be a potential therapy target in this cancer entity.
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