Estradiol-induced proliferation of papillary and follicular thyroid cancer cells is mediated by estrogen receptors alpha and beta.
Premenopausal women are at highest risk for papillary and follicular thyroid carcinoma, implicating a role for estrogens in thyroid cancer. The expression of estrogen receptors alpha and beta (ER), the effects of estradiol (E2), selective estrogen receptor modulators (SERMs) 4-hydroxytamoxifen and raloxifene, and ER subtype selective agonists were examined in NPA87 and KAT5 papillary and WRO follicular thyroid carcinoma cell lines. All three thyroid cancer cell lines expressed full-length ERalpha and ERbeta proteins with cytoplasmic localization that was unaffected by E2. ICI 182,780 (Fulvestrant, an ER antagonist), and inhibitors of non-genomic E2-activated MAPK and PI3K signaling blocked E2-induced cell proliferation. SERMs acted in a cell line-specific manner. No E2-induced estrogen response element (ERE)-driven reporter activity was observed in transiently transfected thyroid cancer cells. However, E2 increased transcription of established endogenous E2-target genes, i.e., cathepsin D in WRO and cyclin D1 in both KAT5 and WRO cells in an ER-dependent manner as validated by inhibitor and siRNA experiments. In contrast, E2 did not increase progesterone receptor expression in the thyroid cancer cell lines. E2 stimulated phosphorylation of ERK1/2 in KAT5 and WRO cells and siERalpha or siERbeta inhibited E2-induced ERK phosphorylation. Expression of the putative membrane estrogen receptor GPR30 was detected in WRO, but not NPA87 or KAT5 cells. GPR30 expression was lower in WRO than MCF-7 human breast cancer cells. Overall, these findings suggest E2-mediated thyroid cancer cell proliferation involves ERalpha and ERbeta transcriptional and non-genomic signaling events.
Kumar
Akhilesh
A
Department of Surgery, University of Louisville School of Medicine, Louisville, KY 40292, USA.
Klinge
Carolyn M
CM
Goldstein
Richard E
RE
D002277:Carcinoma / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004958:Estradiol / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D047629:Estrogen Receptor beta / Q000378:metabolism*; D000077267:Fulvestrant; D006801:Humans; D010766:Phosphorylation; D034741:RNA, Small Interfering / Q000378:metabolism; D020849:Raloxifene Hydrochloride / Q000494:pharmacology; D015398:Signal Transduction; D013629:Tamoxifen / Q000031:analogs & derivatives / Q000494:pharmacology; D013964:Thyroid Neoplasms / Q000378:metabolism*
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D034741:RNA, Small Interfering; D013629:Tamoxifen; C016601:afimoxifene; D000077267:Fulvestrant; D020849:Raloxifene Hydrochloride; D004958:Estradiol