Deoxypodophyllotoxin triggers necroptosis in human non-small cell lung cancer NCI-H460 cells

Deoxypodophyllotoxin (DPT), a naturally occurring microtubule destabilizer, inhibits tubulin polymerization and causes cell cycle arrest at G2/M phase in tumor cells. However, the anti-tumor effect and specific mechanism of DPT in non-small cell lung cancer (NSCLC) are still poorly understood. In this study, we determined the anti-tumor effect and potential mechanism of DPT in the NSCLC cell line, NCI-H460 (H460). First, we demonstrated that DPT significantly inhibits the proliferation of H460 cells in vitro and the growth of H460 xenografts in vivo. In further studies, DPT triggered necroptosis in H460 cells with the following characteristics: (I) necrotic cell death morphology; (II) autophagy; (III) loss of plasma membrane integrity; (IV) loss of mitochondria membrane potential; (V) elevation of reactive oxygen species levels; and (VI) specific inhibition of necroptosis via a small molecule, necrostatin-1. This study also revealed that DPT has a similar effect towards the drug-sensitive cancer cell line, H460, and the drug-resistant cell line, H460/Bcl-xL. To our knowledge, this is the first report to document the induction of necroptosis by a microtubule-targeting agent to circumvent cancer drug resistance, thereby providing a new potential choice for clinical cancer therapy, especially drug-resistant cancer therapy.