Figure 4. Afatinib suppresses phosphorylation of EGFR mutants containing the L718V/Q mutations.

Western blots of 293T cells transiently transfected with pcDNA3.1(–) containing EGFR with the indicated mutations, treated for one hour with varying concentrations of the indicated TKIs. A and B show a direct comparison of EGFR^L858R, EGFR^L858R+C797S, EGFR^L858R+L718V and EGFR^L858R+L718Q treated with 100 nM osimertinib, erlotinib, or afatinib. C and D show dose-dependent changes in EGFR phosphorylation of EGFR^L858R+L718V and EGFR^L858R+L718Q compared with EGFR^L858R+C797S and EGFR^L858R+T790M treated with increasing doses of afatinib. E. Comparison of the effect of 100 nM osimertinib on L858R and exon 19 deletion mutants. Sensitivity of the exon 19 deletion mutants with or without the indicated mutations to varying concentrations of osimertinib (F), erlotinib (G) or afatinib (H). All blots are representative of n=2 biological replicates. EV, empty vector.