Effect of 3β-hydroxysteroid dehydrogenase gene on inducible nitric oxide synthase/proteinkinase C signal pathway induced by di (2-ethylhexyl) phthalate
WANG Li1,2, HU Xin-nan1, XU Xin-yun1, QIN Xiao-yun1, ZHENG Kai1,2, WANG Bing-yu1,2, ZENG Huai-cai2
1. Institute of Environmental Health, Shenzhen Municipal Center for Disease Control and Prevention, Shenzhen, Guangdong 518055, China; 2. School of Public Health, University of South China, Hengyang, Hunan 421001, Hunan
Abstract:Objective To explore the effect of di-(2-ethylhexyl) phthalate (DEHP) on the expression of genes and proteins related to signal pathway of inducible nitric oxide synthase (iNOS) and protein kinase C (PKC) in MCF-7 cells and the role of 3β-hydroxysteroid dehydrogenase (3β-HSD) gene in these processes. Methods MCF-7 cells, 3β-HSD silencing cells and 3β-HSD over-expressed cells were exposed to DEHP at the concentration of 0.00-0.40 mmol/L for 24 hours. The changes in the expression levels of iNOS/PKC signal pathway-related genes were detected. After treatment with the inhibitors of iNOS/PKC signal pathway, the cells were exposed to DEHP at different concentration, and then the changes in the expression levels of iNOS/PKC signal pathway-related genes and apoptosis genes were detected by quantitative PCR (q-PCR) and Western blot. Results The gene and protein expression levels of iNOS and PKCα in the groups of MCF-7 cells exposed to different concentration of DEHP were higher than those in the control group. Compared with MCF-7 cellsexposed to thesame dose of DEHP, the expression levels of iNOS and PKCα mRNA in 3β-HSD silencing cells decreased, but the expression levels of iNOS and PKCα mRNA in 3β-HSD over-expressed cells increased. After treatment with the iNOS inhibitor NG-nitro-L-arginine methyl ester 50 μmol/L, the expression ofiNOS, Bax, Caspase-3 and Caspase-8 in DEHP-treated group was down-regulated. After treatment with PKCα inhibitor chelerythrine chloride 0.20 μmol/L, the expression of PKCα in DEHP-treated group was down-regulated. No significantly decreased expression of genes was found in each group treated with inhibitor as compared with the control group, and also no significant differences were observed in the changing trends of genes between the DEHP-exposure groups treated and untreated with inhibitor. Conclusions DEHP-induced toxicity may be related to iNOS/PKC signal pathway, and 3β-HSD may regulate the expression of iNOS/PKC signaling pathway-related genes.