N-Nitroso metabolite of carbofuran induces apoptosis in CHL cells by cytochrome c-mediated activation of caspases.

摘要

Carbofuran is an anti-acetylcholinesterase insecticide regarded as a relatively safe chemical based on extensive toxicological data. However, the N-nitroso metabolite of carbofuran has been reported to be genotoxic. We previously observed that N-nitrosocarbofuran (NOCF) induces apoptosis and cell cycle arrest in Chinese hamster lung (CHL) fibroblasts. To extend our initial observations, we investigated the molecular mechanism of NOCF-induced apoptosis. Treatment of cells with NOCF caused dose-dependent upregulation of cytosolic factors, such as Bax and Bid, and release of cytochrome c, which were accompanied by activation of caspase-9. We also observed activation of caspase-8 and caspase-3, and subsequent cleavage of poly(ADP-ribose) polymerase. A broad-spectrum caspase inhibitor and a caspase-8-specific inhibitor completely blocked caspase-3 activation and cell death induced by NOCF. These results suggest that the mitochondrial pathway is primarily involved in the NOCF-induced apoptosis of CHL cells.