The effect of TGF-β signaling on regulating proliferation of uterine leiomyoma cell via ERα signaling activated by bisphenol A, octylphenol and nonylphenol in vitro.

OBJECTIVES: To study the transforming growth factor beta (TGF-β) signaling pathway in interactions with estrogen receptor alpha (ERα) signaling pathway mediating the growth of human uterine leiomyoma (UL) activated by phenolic environmental estrogens (EEs).

METHODS: The subcultured UL cells were used to determine the validation of TGF-β3 for the viability of human UL cells using CCK-8 assay, mRNA expressions of ERα, and c-fos by quantitative reverse transcription polymerase chain reaction method, and expressions of p-Smad3, SnoN, and c-fos proteins by Western blot assay in each treatment group.

RESULTS: Compared with each of EEs or TGF-β3 treatment, slightly decrease in the proliferation rate of UL was detected in the coexistence of each EE with TGF-β3. Interestingly, mRNA expressions of ERα and c-fos reduced in the setting of coexistence of TGF-β3 and EEs. Somehow, the expression of p-Smad3 and c-fos proteins significantly decreased in each of E2, bisphenol A (BPA), nonylphenol (NP), and octylphenol (OP) group, as well as the expression of SnoN protein significantly reduced only in BPA and NP groups, followed by TGF-β3 treatment. With the overlaid action of ICI 182,780, the expression of p-Smad3 protein significantly increased in OP group, but slightly increased in E2, BPA, NP, and OP groups. However, compared with the control group, the expression of SnoN and c-fos proteins significantly decreased in the same setting.

CONCLUSION: Both ERα signaling pathway and TGF-β signaling pathway have different roles in governing UL cell proliferation. The phenolic EEs can be a promoter to the proliferation of UL cells, which is mediated by ERα signaling pathway and cross-talked with TGF-β signaling pathway.