Synthesis and antitumor activity of a novel class of covalent inhibitors of EGFR with 2-indolone backbone.

The percentage of people with lung cancer remains high. Given that the majority of NSCLC patients are currently on third-generation clinical agents, the search for a class of highly effective and low-toxicity inhibitors is critical. Hence, in the present study, 24 compounds were synthesized by scaffold hopping with 2-indolone as the parent nucleus. The anti-tumor activity against two human non-small cell lung cancer cell lines (A549 and H1975) was evaluated in vitro using Osimertinib as a positive control drug. Results demonstrated that compound T16 (IC = 0.386 ± 0.032 μM) exhibited comparable anti-tumor activity to Osimertinib (IC = 0.098 ± 0.006 μM). Moreover, T16 showed a twofold higher selectivity than Osimertinib in normal HEK293 cells. Subsequent studies confirmed that compound T16 inhibited colony formation in both H1975 and A549 cells at concentrations consistent with the initial screening assay results. Additionally, it suppressed migration of H1975 cells, and induced apoptosis while significantly reducing phosphorylation levels of EGFR and AKT proteins. In vivo experiments demonstrated effective tumor suppression after 20 days' treatment with compound T16 in CDX model. RNA sequencing analysis further revealed that compound T16 induced expression of HMOX1 leading to ferroptosis trigger. Additionally, molecular docking results indicate that T16 is chimerized into the mutant protein pocket in an 'arch-bridge' conformation.