Inhibitory effect of polypeptide from Chlamys farreri on UVA-induced apoptosis in human keratinocytes.

Polypeptide from Chlamys farreri (PCF, Mr = 879) is a novel marine active product isolated from gonochoric Chinese scallop Chlamys farreri which has been served as sea food for several thousand years. As an octapeptide, PCF consists of 8 amino acids, namely, Pro, Asn, Ser, Thr, Arg, Hyl, Cys, and Gly. PCF had been identified as a marine chemopreventive drug that protected hairless mice's epidermis against UV-induced damage in our previous study. However, the molecular mechanisms that underlie the effect of PCF on ultraviolet A-induced apoptosis in ketatinocytes are not well understood yet. In the present study, PCF was investigated as a potential inhibitory agent for UVA-induced apoptosis in a human keratinocyte cell line, HaCaT. The effects of PCF on UVA-induced generation of ROS and MDA, DNA damage, apoptosis rate were examined. We also investigated whether PCF could inhibit UVA-induced decreasing of mitochondrial membrane potential and the changing of morphology of the cells. We found that, compared with UVA only group, PCF attenuated UVA-induced generation of ROS and MDA, increased the mitochondrial membrane potential, and decreased the apoptosis rate. These results indicate that PCF may protect HaCaT keratinocytes against UVA-induced apoptosis.