Design, synthesis, and biological evaluation of evodiamine-indolequinone hybrids as novel NQO1 agonists against non-small cell lung cancer

NQO1 is a FAD containing NAD(P)H-dependent oxidoreductase that catalyzes the reduction of quinones and related substrates, which plays an important role in the treatment of non-small cell lung cancer (NSCLC). Based on the indolequinone structure from 5-methoxy-2-methylindole, the indolequinone of NQO1 agonists was first coupled with amino-evodiamine derivatives by esterification reaction, and sixteen new compounds targeting NQO1 were developed. Among them, compounds 11b and 12d (IC50 = 2.72 or 3.66 µM, respectively) were showed better activity by cytotoxicity assay than the reference drug EVO (IC50 = 19.65 µM). Furthermore, the results of flow cytometry analysis showed that compounds 11b and 12d promoted apoptosis in A549 cells, blocked the cell cycle to the G2/M stage and caused a burst of reactive oxygen species. Western blotting experiments revealed that compounds 11b and 12d, after 24 h of treatment in A549 cells, downregulate the expression of Keap1 while upregulating the expression of Nrf2, NQO1, and HO-1. This suggests that compounds 11b and 12d increase cellular antioxidant capacity by regulating the Keap1/Nrf2/NQO1 antioxidant pathway. In vivo anti-tumor experiments showed that the reference drugs EVO (TGI = 15.94 %) and 5-Fu (TGI = 27.54 %) inhibited the proliferation of tumor tissue, while compound 11b could better inhibit the proliferation of tumor tissue (TGI = 39.13 %). In conclusion, our research results suggest that compounds 11b and 12d are potent agonism of the NQO1 signaling pathway and provide a potential opportunity to improve the treatment of NSCLC.