Mechanisms behind the inhibition of lung adenocarcinoma cell by shikonin.

Shikonin, a natural naphthoquinone isolated from a traditional Chinese medicinal herb, can exert inhibitory effect on tumor cell growth. However, little has been known concerning the effect of shikonin on lung adenocarcinoma cell and underlying mechanisms. In the present study, we investigated the effect of shikonin on the proliferation, cell cycle arrest, and apoptosis in human lung adenocarcinoma cells. We found that shikonin significantly suppressed the proliferation of lung adenocarcinoma cells compared with control in dose- and time-dependent manner (P < 0.05). In the meantime, our results showed that shikonin markedly increased the proportion of A549 cells at stage G1 as well as induced apoptosis in A549 cells. Furthermore, suppressed CCND1 and elevated caspase3 and caspase7 expression levels at mRNA were found in this study, indicating that shikonin may inhibit the growth of lung adenocarcinoma cell by changing cell cycle and promoting cell apoptosis through the regulation of CCND1, caspase3, and caspase7. Although more studies are needed, this study suggests that shikonin has the potential to be used as an anti-cancer agent in the treatment of lung adenocarcinoma.