The graph shows the calculated data lg(cond(W)) on the effect of oncogenic mutations on the binding of EGFR to Afatinib.
The stability lg(cond(W)) value indicates an increase in the binding of Afatinib to EGFR (G719S/T790M) compared to wtEGFR.
A direct correlation is observed between the calculated lg(cond(W)) and experimental data IC50.
Inhibition of the wild-type and mutant EGFRs by increasing concentrations of gefitinib.
NIH3T3 cells retro-virally transferred with EGFRs were pre-treated with the indicated concentrations of gefitinib for 4 h. Activation of EGFRs, as monitored by auto-phosphorylation (Tyr1173). IC50s were measured by quantifying the phosphorylation signals.
Therefore, the T790M mutation effectively enhances the drug resistance of the G719S mutant. The acquired drug resistance of the G719S/T790M double mutant is not attributed to the reduced binding of gefitinib, because the G719S/T790M double mutant bound gefitinib with a Kd=5.6 nM, which is tighter than G719S (Kd=31.9 nM) and the wild type (Kd=14.2 nM).
[Structural basis for the altered drug sensitivities of non-small cell lung cancer-associated mutants of human epidermal growth factor receptor]