The Roles of p38 MAPK and ERK1/2 in Coplanar Polychlorinated Biphenyls-Induced Apoptosis of Human Extravillous Cytotrophoblast-Derived Transformed Cells.

BACKGROUND/AIMS The purpose of this study was to investigate the relationships among exposure to coplanar polychlorinated biphenyls (Co-PCBs), the expression of gC1qR and the underlying intracellular apoptotic signaling pathways of human extravillous cytotrophoblast (EVCT)-derived transformed cells (HTR-8/SVneo and HPT-8). METHODS Apoptosis in HTR-8/SVneo and HPT-8 cells was assessed using flow cytometric analysis. gClqR expression was examined in the HTR-8/SVneo and HPT-8 cells using real-time qPCR and western blot analyses. The phosphorylations of p38 mitogen-activated protein kinase (p38 MAPK) (Thr180/Tyr182) and extracellular signal-regulated kinase (ERK) 1/2 (Thr202/Thr204) were detected using western blot analyses. RESULTS The HTR-8/SVneo and HPT-8 cells treated with Co-PCBs exhibited significantly increased gClqR expression, p38 MAPK/ERK activation and an up-regulation of cellular apoptosis. These effects were abrogated by the application of gC1qR small interfering RNA (siRNA). Furthermore, apoptosis in HTR-8/SVneo and HPT-8 cells was observed upon treatment with Co-PCBs, and these effects were reversed by the p38 MAPK pathway inhibitor SB203580 or the ERK1/2 pathway inhibitor PD098059. CONCLUSION These data support a mechanism wherein gC1qR plays a crucial p38 MAPK/ERK signaling pathway-dependent role in Co-PCBs-induced apoptosis of human EVCT-derived transformed cells.