TLR8 agonist Motolimod-induced inflammatory death for treatment of acute myeloid leukemia.

The clinical treatment of AML is dominated by "7 + 3" therapy, but it often shows great toxicity and limited therapeutic efficacy in application. Therefore, it is urgent to develop novel therapeutic strategies to achieve safe and efficient treatment of AML. Small-molecule inhibitors have the characteristics of high specificity, low off-target toxicity and remarkable therapeutic effect, and are receiving more and more attention in tumor therapy. In this study, we screened a library of 1972 FDA-approved small molecular compounds for those that induced the inflammatory death of AML cells, among which the TLR8 agonist Motolimod (MTL) showed stronger anti-AML activity in the animal model but slight affection on normal lymphocytes in control mice. In terms of mechanism, cellular experiments in AML cell lines proved that TLR8 and LKB1/AMPK are the key distinct mechanisms for MTL triggered caspase-3-dependent cell death and the expression of a large number of inflammatory factors. In conclusion, our findings identified the immunoactivator MTL as a single agent exerting significant anti-AML activity in vitro and in vivo, with strong potential for clinical translation.