Dimethyl fumarate induces necroptosis in colon cancer cells through GSH depletion/ROS increase/MAPKs activation pathway

Background and purpose: Dimethyl fumarate (DMF) is a newly approved drug for the treatment of relapsing forms of multiple sclerosis and relapsing-remitting multiple sclerosis. Here, we investigated the effects of DMF and its metabolites mono-methylfumarate (MMF and methanol) on different gastrointestinal Cancer cell lines and the underlying molecular mechanisms involved.

Experimental approach: Cell viability was measured by the MTT or CCK8 assay. Protein expressions were measured by Western blot analysis. LDH release, live- and dead-cell staining, intracellular GSH levels, and mitochondrial membrane potential were examined by using commercial kits.

Key results: DMF but not MMF induced cell Necroptosis, as demonstrated by the pharmacological tool necrostatin-1, transmission electron microscopy, LDH and HMGB1 release in CT26 cells. The DMF-induced decrease in cellular GSH levels as well as cell viability and increase in Reactive Oxygen Species (ROS) were inhibited by co-treatment with GSH and N-acetylcysteine (NAC) in CT26 cells. DMF activated JNK, p38 and ERK MAPKs in CT26 cells and JNK, p38 and ERK inhibitors partially reversed the DMF-induced decrease in cell viability. GSH or NAC treatment inhibited DMF-induced JNK, p38, and ERK activation in CT26 cells. DMF but not MMF increased Autophagy responses in SGC-7901, HCT116, HT29 and CT26 Cancer cells, but Autophagy inhibition did not prevent the DMF-induced decrease in cell viability.

Conclusion and implications: DMF but not its metabolite MMF induced Necroptosis in colon Cancer cells through a mechanism involving the depletion of GSH, an increase in ROS and activation of MAPKs.