Suppression of growth of A549 lung cancer cells by waltonitone and its mechanisms of action.

Natural compounds are a great source of cancer chemotherapeutic agents. Our investigation indicates that waltonitone, a triterpene extracted from medicinal plants, inhibits the proliferation of A549 cells in a concentration- and time-dependent manner. Waltonitone induced apoptosis of A549 cells in a concentration-dependent manner, as determined by fluorescence microscopy and flow cytometry. The apoptosis was accompanied by increased Bax protein levels and decreased Bcl-2 protein levels in A549 cells. Furthermore, the treatment of A549 cells with waltonitone altered the expression of miRNAs. We found that 27 miRNAs were differentially expressed in waltonitone-treated cells, of which 8 miRNAs target genes related to cell proliferation and apoptosis. In summary, our results demonstrate that waltonitone has a significant inhibitory effect on the proliferation of A549 cells. It is possible that upregulation of Bax/Bcl-2 and regulation of expression of specific miRNAs play a role in inhibition of proliferation and induction of apoptosis in waltonitone-treated cells. Waltonitone can be applied to lung carcinoma as a chemotherapeutic candidate.