224 A GROWTH OF HUMAN BG-1 CANCER CELLS EXPRESSING ESTROGEN RECEPTORS WAS ENHANCED BY SYNTHETIC PYRETHROIDS, LAMBDA-CYHALOTHRIN AND CYPERMETHRIN, VIA AN ESTROGEN RECEPTOR-DEPENDENT SIGNALING PATHWAY

Abstract

Synthetic pyrethroids (SP) are the most common pesticides in recent use, which are used as indoor pest control. The widespread use of SPs has resulted in extensive exposure to wildlife and human. Recently some SPs are suspected as endocrine disrupting chemicals (EDC) and have been assessed for their potential estrogenicity by various assays. In this study, we examined the estrogenic effects of lambda-cyhalothrin (LCT) and cypermethrin (CP), the most commonly used pyrethroid insecticides in Korea, using BG-1 ovarian cancer cells expressing oestrogen receptors (ER). To evaluate the estrogenic activities of two SPs, LCT and CP, we employed MTT assay and reverse-transcription polymerase chain reaction (RT–PCR). In MTT assay, LCT (10^–6 M) and CP (10^–5 M) significantly induced the growth of BG-1 cancer cells, 1.61 ± 0.1 and 1.45 ± 0.06 times, respectively, as 17β-oestradiol (E2, 10^–9 M, 2.73 ± 0.25 times) did. LCT or CP-induced cell growth was reversed to a control level (DMSO) by addition of ICI 182 720 (10^–8 M), an ER antagonist, suggesting that this effect appears to be mediated by an ER-dependent manner. Moreover, RT–PCR results showed that transcriptional level of ERα expression was significantly down-regulated by LCT and CP as in case of E2. Taken together, these results indicate that LCT and CP may possess estrogenic potentials to stimulate ovarian cancer cells expressing ERs via an ER-dependent manner, and these collective results confirm the carcinogenicity of these SP, LCT and CP, in ER-positive cells or tissues.