Non-mitotic effect of albendazole triggers apoptosis of human leukemia cells via SIRT3/ROS/p38 MAPK/TTP axis-mediated TNF-α upregulation.

Albendazole (ABZ) is a microtubule-targeting anthelmintic that acts against a variety of human cancer cells, but the dependence of its cytotoxicity on non-mitotic effect remains elusive. Thus, we aimed to explore the mechanistic pathway underlying the cytotoxicity of ABZ in human leukemia U937 cells. ABZ-induced apoptosis of U937 cells was characterized by mitochondrial ROS generation, p38 MAPK activation, TNF-α upregulation and activation of the death receptor-mediated pathway. Meanwhile, ABZ induced tubulin depolymerization and G2/M cell cycle arrest. ABZ-induced SIRT3 degradation elicited ROS-mediated p38 MAPK activation, leading to pyruvate kinase M2-mediated tristetraprolin (TTP) degradation. Inhibition of TTP-mediated TNF-α mRNA decay elicited TNF-α upregulation in ABZ-treated cells. Either the overexpression of SIRT3 or abolishment of ROS/p38 MAPK activation suppressed TNF-α upregulation and rescued the viability of ABZ-treated cells. In contrast to the inhibition of ROS/p38 MAPK pathway, SIRT3 overexpression attenuated tubulin depolymerization and G2/M arrest in ABZ-treated cells. Treatment with a SIRT3 inhibitor induced TNF-α upregulation and cell death without the induction of G2/M arrest in U937 cells. Taken together, our data indicate that ABZ-induced SIRT3 downregulation promotes its microtubule-destabilizing effect, and that the non-mitotic effect of ABZ largely triggers apoptosis of U937 cells via SIRT3/ROS/p38 MAPK/TTP axis-mediated TNF-α upregulation. Notably, the same pathway is involved in the ABZ-induced death of HL-60 cells.