Luteolin induced DNA damage leading to human lung squamous carcinoma CH27 cell apoptosis.

Luteolin is an active compound from the Lonicera japonica (Caprifoliaceae). Luteolin (50 microM)-induced human lung carcinoma CH27 cell apoptosis is a typical apoptosis that was accompanied by a significant DNA condensation and apoptotic body formation. Luteolin-induced apoptosis is related to its ability to change the expression of apoptotic markers, such as caspase-3 (caspase-dependent) and apoptosis-inducing factor (caspase-independent) protein expression. The alkaline microgel electrophoresis technique (comet assay), which is the most sensitive, was used for estimation of the luteolin-induced DNA single strand breaks in this study. DNA-damaging effects of luteolin on DNA single strand breaks have been demonstrated in our study. In this study, luteolin induced S-phase cell cycle arrest and increased the mRNA of DNA repair enzymes such as human MutT homologue, 8-oxoguanine-glycosylase and apurinic endonuclease. Our data suggested that luteolin induces CH27 cell apoptosis by caspase-dependent and -independent pathway and the effect of luteolin on apoptosis of CH27 cells is associated with DNA damage and the expression of DNA repair enzymes.