ClC-3 chloride channel prevents apoptosis induced by thapsigargin in PC12 cells

摘要

Cell volume can be altered by two different ways, swelling and shrinkage. Cell swelling is regulated by volume-regulated CI- channel (VRC). It is not well understood whether shrinkage is regulated by VRC. We previously found that antisense oligonucleotide specific to CIC-3 (CIC-3 antisense) prevented cell proliferation, which was related to cell swell volume regulation. In the present study, we further studied the role of CIC-3 CI- channel in cell apoptosis which was related to cell shrinkage volume regulation by using antisense oligonucleotide specific to CIC-3 (CIC-3 antisense) and CIC-3 cDNA transfection techniques. We found that thapsigargin (TG), a specific inhibitor of the endoplasmic reticulum calcium ATPase, evoked apoptotic morphological changes (including cytoplasmic blebbing, condensation of nuclear chromatin, and the formation of apoptotic bodies), DNA laddering, and caspase-3 activation in PC12 cells (Pheochromocytoma-derived cell line). TG increased the cell apoptotic population with a decrease in cell viability. These effects were consistent with the decrease in endogenous CIC-3 protein expression, which was also induced by TG. Overexpression of CIC-3 significantly inhibited TG effect on PC12 cell apoptosis, whereas the CIC-3 antisense produced opposite effects and facilitated apoptosis induced by TG. Our data strongly suggest that CIC-3 channel in PC12 cells mediates TG-induced apoptotic process through inhibitory mechanism. Thus, it appears that CIC-3 CI- channel mediates both cell proliferation and apoptosis through accelerative and inhibitory fashions, respectively.