Ultraviolet-B radiation causes an upregulation of survivin in human keratinocytes and mouse skin

Understanding of the mechanism of ultraviolet (UV)-mediated cutaneous damages is far from complete. The cancer-specific expression of Survivin, a member of the inhibitor of apoptosis family of proteins, coupled with its importance in inhibiting cell death and in regulating cell division, makes it a target for cancer treatment. This study was designed to investigate the modulation of Survivin during UV response, both in vitro and in vivo. We used UV-B-mediated damages in normal human epidermal keratinucytes (NHEK) cells as an in vitro model and SKH-1 hairless mouse model for the in vivo studies. For in vitro studies, NHEK were treated with UV-B and samples were processed at 5, 15, 30 min, 1, 3, 6, 12 and 24 h after treatment. Our data demonstrated that UV-B exposure (50 rnJ/cm(2)) to NHEK resulted in a significant upregulation in Survivin messenger RNA (mRNA) and protein levels. We also observed that UV-B exposure to NHEK resulted in significant (1) decrease in Smac/DIABLO and (2) increase in p53. For in vivo studies, the SKH-1 hairless mice were subjected to a single exposure of UV-B (180 rnJ/cm(2)), and samples were processed at 3, 6, 12 and 24 h after UV-B exposure. UV-B treatment resulted in a significant increase in protein or mRNA levels (or both) of Survivin, phospho-Survivin and p53 and a concomitant decrease in Smac/DIABLO in mouse skin. This study demonstrated, for the first time, the involvement of Survivin (and the associated events) in UV-B response in vitro and in vivo in experimental models regarded to have relevance to human situations.