In silico molecular target prediction unveils mebendazole as a potent MAPK14 inhibitor

International audienceThe concept of polypharmacology involves the interaction of drug mole- cules with multiple molecular targets. It provides a unique opportunity for the repurposing of already-approved drugs to target key factors involved in human diseases. Herein, we used an in silico target prediction algorithm to investigate the mechanism of action of mebendazole, an antihelminthic drug, currently repurposed in the treatment of brain tumors. First, we con- firmed that mebendazole decreased the viability of glioblastoma cells in vitro (IC50 values ranging from 288 nM to 2.1 μM). Our in silico approach unveiled 21 putative molecular targets for mebendazole, includ- ing 12 proteins significantly upregulated at the gene level in glioblastoma as compared to normal brain tissue (fold change > 1.5; P < 0.0001). Vali- dation experiments were performed on three major kinases involved in can- cer biology: ABL1, MAPK1/ERK2, and MAPK14/p38a. Mebendazole could inhibit the activity of these kinases in vitro in a dose-dependent man- ner, with a high potency against MAPK14 (IC50 = 104 +/- 46 nM). Its direct binding to MAPK14 was further validated in vitro, and inhibition of MAPK14 kinase activity was confirmed in live glioblastoma cells. Consis- tent with biophysical data, molecular modeling suggested that mebendazole was able to bind to the catalytic site of MAPK14. Finally, gene silencing demonstrated that MAPK14 is involved in glioblastoma tumor spheroid growth and response to mebendazole treatment. This study thus high- lighted the role of MAPK14 in the anticancer mechanism of action of mebendazole and provides further rationale for the pharmacological target- ing of MAPK14 in brain tumors. It also opens new avenues for the devel- opment of novel MAPK14/p38a inhibitors to treat human diseases