SCP, a polysaccharide from Schisandra chinensis, induces apoptosis in human renal cell carcinoma Caki-1 cells through mitochondrial-dependent pathway via inhibition of ERK activation.

This study is the first to investigate the anticancer effect of Schisandra chinensis polysaccharide (SCP) in renal cell carcinoma (RCC) cells. The results revealed that SCP treatment showed high cytotoxic potency in Caki-1 cells by inducing apoptosis, which is associated with the disruption of mitochondrial membrane potential (MMP), release of cytochrome c into the cytosol, increase of Bax/Bcl-2 ratio, activation of caspase-3/9, and cleavage of poly(ADP-ribose) polymerase (PARP). Furthermore, pan-caspase inhibitor (z-VAD-fmk) significantly blocked SCP-induced apoptosis and PARP cleavage in Caki-1 cells. As well, we also observed that SCP inhibited the phosphorylation of ERK1/2, whereas it had no significant inhibition effect on the phospho-p38 and phospho-JNK activity. All the above parameters provided scientific evidence that SCP induced mitochondrial-mediated apoptosis in Caki-1 cells through the inactivation of ERK pathways, which may shed further light on its potential application as a cancer chemopreventive agent against RCC.