Fig. 1
Sequence-dependent synergistic effect on tumor cell growth inhibition in EGFR-mutant NSCLC cell lines. A Schematic presentation of three different combination strategies. B Three NSCLC cell lines, including EGFR L858R/T790M H1975, EGFR-del19 HCC827 and EGFR-wide type A549, were exposure to different combination strategies of pemetrexed and aumolertinib or alone with serious doses at constant ratios of the IC50 (n = 6). C Combination indexes (CI) of different combination mode were evaluated in three NSCLC cell lines. The CI value > 1.45 represents antagonistic effect, 0.7 < CI < 1.45 represents addictive effect while CI < 0.7 represents synergistic effect (n = 6). D Representative images of colony formation assay of HCC827 after different drug treatment. 20 μM pemetrexed and 20 nM aumolertinib were used for HCC827 (n = 3). E A western bolt assay was performed to detect the changes of PARP1, cleaved PARP1 and cleaved Caspase 3 expression in H1975 and HCC827 cell lines. In this experiment, 20 μM pemetrexed and 2 μM aumolertinib were used for H1975. 20 μM pemetrexed and 20 nM aumolertinib were used for HCC827. F Quantification of the western blot band intensity was performed using ImageJ and GAPDH was used as loading controls (n = 3). Con represents control; P represents pemetrexed; A represents aumolertinib; P + A represents concomitant treatment with pemetrexed and aumolertinib; P-A represents pemetrexed treatment followed by aumolertinib treatment; A-P represents aumolertinib treatment followed by pemetrexed treatment. All of the data were expressed as the mean ± SEM, ns represents no significance, * p < 0.05, ** p < 0.01 and *** p < 0.001