215 SNAIL AND SLUG, MARKERS OF EPITHELIAL MESENCHYMAL TRANSITION, APPEARED TO BE ALTERED BY ALKYL-PHENOLS, BISPHENOL A AND NONYL-PHENOL, IN OVARIAN CANCER CELLS EXPRESSING ESTROGEN RECEPTORS

Abstract

The ovary is the important organ to produce oocytes. Any disorder will affect embryo production. Ovarian cancer is one of gynecologic cancers in women which can affect ovarian functions. Oestradiol (E2) may be involved in ovarian cell growth and epithelial-mesenchymal transition (EMT) for diverse functions. EMT is an important process in embryo development and tumour migration or progression. Bis-phenol A (BPA) and nonyl-phenol (NP) have an estrogenic property, which can be suspected as endocrine disrupting chemicals (EDC). In this study, it has been examined whether BPA and NP can cause EMT process and migration in BG-1 ovarian cancer cells. To confirm the effect of these EDCs, BG-1 ovarian cancer cells were cultured and treated with DMSO (0.1%), E2 (10^–7 M), BPA (10^–6 M) and NP (10^–6 M) for 0, 6, and 24 h. The mRNAs were extracted to perform reverse-transcription (RT)-PCR and the changes in the mRNA expressions were analysed by ANOVA test. Following treatments with BPA and NP, alterations of EMT markers; that is, vimentin and E-cadherin, were examined at mRNA levels by RT-PCR. The levels of vimentin were up-regulated by E2, BPA, or NP in a time-dependent manner. In addition, transcriptional factors of EMT response, i.e. snail and slug, were enhanced by these treatments more than 2 times. BG-1 cells were exposed to these EDCs for 0, 24, and 48 h. Vimentin and snail proteins were induced by E2, BPA, or NP, while the expression of E-cadherin was decreased by them. To reveal that this EMT response is affected by oestrogen receptor (ER), the cells were treated with these EDCs in the presence of an ER antagonist, ICI 182 780 (10^–6 M). Treatment with ICI 182 780 reversed EDC-induced alteration of these EMT markers, E-cadherin, vimentin, and snail. Since EMT response can cause metastasis, a scratch assay was performed to show migration caused by BPA or NP. BPA or E2 enhanced migratory capability of these BG-1 cells. Taken together, these results indicate that BPA and NP, potential EDC, may have an ability to influence ovarian cancer metastasis via regulating snail and slug genes in ER-positive ovarian cancers. In a future study, their effects in inducing EMT and migration will be tested in a xenograft mouse model.

This work was supported by a grant from the Next-Generation BioGreen 21 Program (no. PJ009599), Rural Development Administration, Republic of Korea.