Auricularia polytricha polysaccharides induce cell cycle arrest and apoptosis in human lung cancer A549 cells

In the present study, the anticancer activity of Auricularia polytricha polysaccharides (APPs) towards A549 human lung cancer cells and its underlying mechanisms were investigated. APPs significantly inhibited the proliferation and DNA synthesis of A549 cells in a concentration-dependent manner. The compound also induced apoptosis in A549 cells by arresting cell cycle progression at the G0/G1 phase. Western blotting assay demonstrated that APPs significantly increased the expression of cyclin-dependent kinase (CDK) inhibitors p53 and p21, whereas the expression of cyclin A, cyclin D, and CDK2 were decreased by treatment with APPs. This apoptotic induction in APPs-treated A549 cells was also associated with the release of cytochrome c from mitochondria to cytosol, which in turn resulted in the activation of caspase-9 and -3, and the cleavage of poly (ADP-ribose) polymerase (PARP). Furthermore, the inhibitory effect of APPs on the growth in BALB/c-nu nude mice bearing A549 cells was also proven. These findings suggested that APPs might be a useful chemotherapeutic agent for lung cancer.