Adaptive Response and Apoptosis Induced by UV Irradiation in Human Keratinocytes and Squamous Cell Carcinomas

Moon, Yong Suk

Abstract

The present study was investigated that the effects of suitable ultraviolet (UV) irradiation to the cell viability, apoptosis and expression of poly(ADP-ribose) polymerase (PARP) in HaCaT and KUMA3 cell lines that are skin keratinocyte and squamous cell carcinoma, respectively. The cell viability of UV irradiation dose appeared high in HaCaT cell line, and the percentage of apoptotic cells appeared higher in KUMA3 cell line. The cell viability in HaCaT cell line pretreated with 5 J/m(2) UV and subsequently treated with 50 J/m(2) UV was higher than that only treated with 50 J/m(2) UV. On the other hand, the percentage of apoptotic cells in KUMA3 cell line only treated with 50 J/m(2) UV was higher than that pretreated with 5 J/m(2) UV and subsequently treated with 50 J/m(2) UV. Immunocytochemical stain using PARP antibody, the most cells show positive reaction of UV irradiation in HaCaT cell line, but some negative reaction cells observe from treated with 50 J/m(2) UV in KUMA3 cell line. The expression level of PARP by western blot analysis, concomitant with generation of the 85 kDa fragment in HaCaT cell line from treated with 50 J/m(2) UV though the 116 kDa band was still retained. On the other hand, the 85 kDa fragment appeared in KUMA3 cell line from treated with 50 J/m(2) UV but the intact PARP of 116 kDa disappears in more doses. These results present that suitable UV irradiation can be effective to apoptosis in squamous cell carcinoma.