Fig. 4

P-A sequence improves the suppression of EGFR signaling pathway. A Schematic presentation of EGFR signaling pathway. B A western blot assay was performed to detect the expression of the representative proteins within EGFR pathway in both H1975 and HCC827 cell line. 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. C Quantification of the western blot band intensity of p-EGFR, EGFR, p-AKT, AKT, p-ERK and ERK in H1975 and HCC827 cell line were performed using ImageJ and GAPDH was used as loading controls (n = 3). D Furthermore, the changes of EGFR signaling pathway in H1975 tumor mass post different drug administration were also determined and quantified (n = 6). Con represents control; P represents pemetrexed; A represents aumolertinib; Osi represents osimertinib; P-A represents pemetrexed treatment followed by aumolertinib treatment. All of the data were expressed as the mean ± SEM, * p < 0.05, ** p < 0.01 and *** p < 0.001