Macrocyclic Polyamine–Quinazoline Conjugates Show Mutant EGFR Inhibition and DNA- Damage-Associated Activity

Abstract Resistance driven by the EGFR C797S mutation limits treatment options for non-small cell lung cancer (NSCLC). We examined macrocyclic polyamine–quinazoline conjugates for mutant EGFR inhibition and DNA-damage-associated activity. Compound 4f inhibited EGFR L858R/T790M/C797S and Del19/T790M/C797S with IC 50 values of 0.65 and 0.85 µM, respectively, while showing weaker activity against wild-type EGFR (IC 50 >5 µM). In 24 h cell viability assays, 4f inhibited NCI-H1975 and osimertinib-resistant H1975/OR cells, with IC 50 values of 8.67 and 6.23 µM, respectively. PC-9 and nonmalignant BEAS-2B cells were less sensitive (IC 50 17.89 and 22.11 µM, respectively). Cell-free plasmid assays showed cleavage by 4f without added transition metal, whereas a matched piperazine analogue retained kinase inhibition but showed no detectable plasmid DNA cleavage. Docking and electrostatic-potential calculations suggested a possible DNA-binding mode involving the quinazoline scaffold and cationic macrocycle. In NCI-H1975 cells, comet assays showed increased DNA migration relative to vehicle-treated controls, while Annexin V-PE/7-AAD analysis detected concentration-dependent apoptosis. These findings identify 4f as a mutant EGFR inhibitor with DNA-damage-associated and pro-apoptotic cellular activities.