Stimulatory effect of oral administration of green tea or caffeine on ultraviolet light-induced increases in epidermal wild-type p53, p21(WAF1/CIP1),and apoptotic sunburn cells in SKH-1 mice

Pretreatment of SKH-1 mice with p.o.-administered 0.6% green tea (6 mg of l yophilized tea solids/ml) or 0.044% caffeine (0.44 mg/ml; concentration pre sent in 0.6% green tea) for 2 weeks enhanced UV-induced increases in the nu mber of p53-positive cells, p21(WAF1/CIP1)-positive cells, and apoptotic su nburn cells in the epidermis, These effects of p.o.-administered green tea or caffeine on early adaptive responses to UV provide the first demonstrati on of in vivo up-regulation of a tumor suppressor gene by a chemopreventive agent. The stimulatory effect of green tea and caffeine on UV-induced incr eases in the number of p53-positive cells, p21(WAF1/CIP1)-positive cells, a nd apoptotic sunburn cells may play a role in the inhibitory effects of tea and caffeine on UV-induced carcinogenesis.