Fig. 4

Acquired EGFR mutation confers JQ1 resistance by stabilizing MYC. a Diagram of the EGFR-I645L mutation in 97-H cells identified by Sanger sequencing of EGFR mRNA. b Western blot analysis of 97-L and 97-H cells with or without EGF stimulation after serum starvation ±10% fetal bovine serum (FBS) for 30 min. Total lysates were subjected to the indicated antibodies. c Western blot analysis of EGFR-WT or EGFR-I645L-expressing 293 T cells lysates after serum starvation or EGF stimulation. Total lysates were subjected to the indicated antibodies. EV is the empty vector-transfected 293 T cells. d Western blot analysis of 97-H cells transfected with scrambled shRNA or shEGFR. Total lysates were subjected to the indicated antibodies. e Western blot analysis of EV, EGFR-WT or EGFR-I645L-expressing 97-L cell lysates after JQ1 treatment. Total lysates were subjected to the indicated antibodies. Band intensities were quantified by Image J software and graphed at the right side. f MYC mRNA expression level in 97-H cells transfected with scrambled shRNA or shEGFR and EGFR-WT or EGFR-I645L-expressing 97-L cells were assessed using qRT-PCR. g Western blot analysis of 97-L-EV and 97-L-EGFR-I645L cells incubated with 100 μM CHX. h Western blot analysis of 97-H-scr and 97-H-shEGFR cells incubated with 100 μM CHX. Data are presented as mean ± s.d. *p < 0.05