Bruceine D induces apoptosis in human non-small cell lung cancer cells through regulating JNK pathway

Bruceine D (BD) is the quassinoids isolated from the traditional Chinese herbal medicine Brucea javanica's fruit, which exhibits anti-cancer activity. Here, we demonstrated that BD inhibited human non-small cell lung cancer (NSCLC) cell lines in vitro that were attributed to the induction of cell apoptosis. Human NSCLC H460 and A549 cell lines were treated with BD, and cell viability was conducted with CCK-8 assay. Cell clone formation was observed by clone formation assay. Cell apoptosis was measured using DAPI staining and flow cytometry. Protein levels was analyzed by western blot. The results showed BD inhibited the cell viability of H460 and A549 cells in a dose-dependent manner with IC50 values of 0.5 and 0.6 μmol/L, respectively, at 48 h of treatment. Treatment with BD (0.125-1.0 μmol/L) dose-dependently promoted chromatin condensation, Annexin V-positive cell population and caspase-dependent apoptosis in H460 and A549 cells. Mechanistically, BD stimulated the phosphorylation of JNK. Furthermore, the anti-cancer effects of BD were alleviated effectively by a specific JNK inhibitor SP600125 in NSCLC cells. In conclusion, the results demonstrated that BD exerted anti-cancer activity against NSCLC cells through JNK activation, which suggests its potent usefulness for prevention and treatment of NSCLC.