Bisphenol compounds modulate estrogen receptor but not Wnt-signaling pathway in human endometrial epithelial (Ishikawa) cell and suppress spheroid attachment

Abstract

BACKGROUND: Bisphenol A (BPA) is one of the well-known chemicals with weak estrogenic activity that might affect our endocrine function, and therefore, named as endocrine disrupting chemicals (EDCs). Due to the potential health hazardous of BPA onto our bodies, BPA is being substituted with Bisphenol S (BPS) and BIsphenol F (BPF). Yet, their effects on human health and reproduction remain largely unknown. OBJECTIVES: To study the effects of bisphenol compounds on cell proliferation, expression of estrogen receptors (ERs) and molecules of Wnt-signaling pathway in human endometrial Ishikawa cell and on spheroid attachment. METHODS: Cell proliferation and trypan blue assays were used to study the effects of bisphenol compounds on Ishikawa cells proliferation. The expression of steroid receptors and molecules of Wnt-signaling pathway were quantified by Western Blotting. Dual Luciferase Assay was used to compare the effect of bisphenol compounds on the activation ERE-luciferase activity. Spheroidsendometrial epithelial cells co-culture assay was used to assess the attachment potential of Jeg-3 spheroid (blastocyst surrogate) onto Ishikawa cells – an in vitro model to mimic embryo attachment in vivo. RESULTS: BPA and BPF at 100μM inhibited Ishikawa cells proliferation at 24h, and BPS at 100μM inhibited cell proliferation at 48h. Similarly BPA and BPF, but not BPS at 100μM reduced total cell number by trypan blue at 24h. BPA, BPS and BPF at 100μM suppressed the expression of ERα, ERβ and GPR30. BPA and BPS at 10μM suppressed the expressions of ERβ and GPR30; while BPF at 1μM suppressed the expression of ERβ and GPR30. BPA and BPF at 100μM suppressed expression of E-cadherin (cell adhesion molecule), but not molecules of Wnt-signaling pathway (GSK-3β and β-catenin). BPA and BPF at 1-10μM and BPS at 10μM activated the ERE-luciferase expression in transfected cells. The effect could be blocked by ICI 182780 (ERs antagonist) and MPP (ERα antagonist), but not by PHTPP (ERβ antagonist) or G15 (GPR30 antagonist). Bisphenols suppressed spheroids attachment at BPA 10-100μM; while BPS and BPF only at 100μM. CONCLUSIONS: High concentrations of Bisphenol compounds inhibit Ishikawa cells proliferation, expression of ER receptors and E-cadherin, but not molecules of Wnt-signaling pathway. BPA, BPS and BPF exhibited weak estrogen activity, partly acting through the ERα. High concentration of Bisphenol compounds inhibits spheroid attachment onto Ishikawa cells suggesting a potential impact on embryo attachment in vivo. [The work is partly supported by GRF grant HKU17120415 to KFL]