Arisostatins A induces apoptosis through the activation of caspase-3 and reactive oxygen species generation in AMC-HN-4 cells

A microbial secondary metabolite, arisostatins A (As-A), was originally discovered as a substance carrying the Antibiotic activity against Gram-positive bacteria and shown to possess potent anti-tumor properties. The mechanism by which arisostatins A initiates Apoptosis remains poorly understood. In the present report we investigated the effect of arisostatins A on activation of the apoptotic pathway in HN-4 cells. Arisostatins A was shown to be responsible for the inhibition of HN-4 cell growth by inducing Apoptosis. Treatment with 4 microM arisostatins A for 24h produced morphological features of Apoptosis and DNA fragmentation in HN-4 cells. Arisostatins A caused dose-dependent Apoptosis and DNA fragmentation of HN-4 cells used as a model. Treatment with Caspase Inhibitor significantly reduced the arisostatins A-induced Caspase 3 activation. In addition, arisostatins A-induced Apoptosis was associated with the generation of Reactive Oxygen Species (ROS), which was prevented by an antioxidant NAC (N-acetyl-cysteine). These data indicate that cytotoxic effect of arisostatins A on HN-4 cells is attributable to the induced Apoptosis and that arisostatins A-induced Apoptosis is mediated by Caspase-3 activation pathway, loss of mitochondrial transmembrane potential (DeltaPsi(m)), and release of cytochrome c into cytosol.