Fig. 2
From: Primary resistance to first-generation EGFR-TKIs induced by MDM2 amplification in NSCLC
MDM2 amplification induces the primary resistance to erlotinib. a Western blotting results for the evaluation of MDM2 expression level among NSCLC cell lines: the HCC2279 cell line was selected for the subsequent experiments for the medium expression of MDM2; b Western blotting results for the target proteins in HCC2279 cell line: β-actin is the protein encoded by the house-keeping gene and balances the protein concentrations between 2 groups; MDM2 expression was upregulated after the transfection of the plasmids; EGFR expression demonstrates no significant difference between 2 groups; ERK proteins including ERK1 and ERK2 were all upregulated in HCC2279-MDM2 group; c Quantified results for western blotting; d The verification of transfection in HCC2279 cell line: the transcription level of MDM2 gene was highly upregulated in HCC2279-MDM2 group; e The curve of the inhibition rate after exposure to erlotinib with different concentration through the examination of MTT assays in the MDM2 amplification group and vector control group of HCC2279 cell line: 10uM erlotinib was set as the medium concentration in this experiment, dramatic resistance to erlotinib could be found in HCC2279-MDM2 group in 1uM, 2uM, 4uM, 8uM, 32uM, 64uM and 128uM erlotinib. The inhibition rates were measured via the formula as follow: Inhibition rate = 1-[(A570-A630) of treated cells/(A570-A630) of control cells]