Estrogen receptor β mRNA in colon cancer cells:: Growth effects of estrogen and genistein

Knowledge regarding the expression of the recently cloned estrogen receptor beta (ER beta) in colonic mucosa is limited. In this study, we demonstrated that five human colon cancer cell lines, HT29, Colo320, Love, SW480, and HCT116, expressed ER beta mRNA, but lacked ER alpha mRNA. Results from a cell growth assay demonstrated that these colon cancer cells were not influenced by estrogen, while genistein possessed slight growth inhibitory effects on HT29, Colo320 and Love cells at 10 mu M, at which concentration is stimulated the growth of ER alpha-positive human breast cancer MCF-7 cells. Tamoxifen inhibited the growth of HT29 and Colo320 cells, dose-dependently, as well as MCF-7 cells. A transfected reporter plasmid containing a vitellogenin estrogen response element could be activated by estradiol in Colo320 cells. Taken together with previous reports, these data suggest that ERa and ER beta may have different biological functions in colon cells. (C) 2000 Academic Press.