Capsaicin induced cell cycle arrest and apoptosis in human esophagus epidermoid carcinoma CE 81T/VGH cells through the elevation of intracellular reactive oxygen species and Ca²⁺ productions and caspase-3 activation

Capsaicin (N-vanillyl-8-methyl-1-nonenamide) is found in pungent fruits, especially in red pepper. Many studies have focused on the anticarcinogenic, antimutagenic or chemopreventive activities of capsaicin. However, the effects of capsaicin on human esophagus epidermoid carcinoma cells have never been investigated. In this study, we investigated the effects of capsaicin on esophagus epidermoid carcinoma cells in vitro and further examined the molecular mechanisms of capsaicin-induced apoptosis in esophagus epidermoid carcinoma cells. Capsaicin decreased the percentage of viable cells of CE 81T/VGH cells, via induction of G0-G1 phase cell cycle arrest and apoptosis. Capsaicin induced G0-G1 phase arrest underwent the promotion of p53 and p21, which is an inhibitor of Cdk2 and cyclin E complex before leading to the inhibitions of both compounds. Capsaicin induced apoptosis in time-dependent manners. Capsaicin-induced apoptosis was in association with the elevation of intracellular reactive oxygen species and Ca²⁺ productions and BAPTA, an intracellular Ca²⁺ chelator, which significantly inhibited capsaicin-induced apoptosis. Collectively, these results suggest that the capsaicin-induced apoptosis in the CE 81T/VGH cells may result from the activation of caspase-3 and intracellular Ca²⁺ release pathway, and it is further suggested that capsaicin has potential as a novel therapeutic agent for the treatment of esophagus epidermoid carcinoma cells.