N-Succinyl-chitosan nanoparticles induced mitochondria-dependent apoptosis in K562.

N-Succinyl-chitosan nanoparticles (NSCNP) are synthetical nanoparticles derived from chitosan. In our previous study, we demonstrated that NSCNP could induce apoptosis in K562 cells, which were evidenced by decreasing cell zeta potential, disrupting the mitochondrial membrane potential, increasing ROS generation and Ca2+ concentration. Here, by western blot we revealed that apoptosis induced by NSCNP was associated with accumulation of cytochrome c in cytosol and elevating expression of apoptosis-promoted protein Bax while depressing expression of apoptosis-restrained protein Bcl-2 in time- and dose-dependence. Cell cycle blocking in G2/M phase was evidenced by kinetic cell cycle analysis. The activations of caspase-9 and 3, not caspase-8 were observed by fluorescent and colorimetric assays. Our data suggested that the apoptotic signals triggered by NSCNP were mediated mainly through the intrinsic mitochondria-dependent pathway.