Fig. 4
From: EGFR feedback-inhibition by Ran-binding protein 6 is disrupted in cancer
STAT3 represses EGFR transcription. a STAT3 KD raises EGFR mRNA (left panel) and EGFR protein levels (right panel) in HEK-293T. b STAT3 binding to the EGFR promoter is impaired by RanBP6 KD. Bottom panel, ChIP experiments on the promoter of indicated genes with STAT3 antibody in LN18 cells with Dox-inducible shRanBP6. Plotted values are relative enrichments to % input, measured for two regions (EGFR_1 and EGFR_2) in 1.5 kb upstream of EGFR transcriptional start site (TSS) (see top panel). Binding to the PTGS2 and HPRT promoter was used as positive and negative control, respectively. c STAT3 and p-STAT3 (Y-705) bind GST-RanBP6 fusion protein in HEK-293T whole-cell lysates. d Expression of a constitutive active STAT3 mutant decreases EGFR mRNA (left panel) and EGFR protein levels (right panel) in HEK-293T. e Inhibition of STAT3 activation by JAK kinase inhibitor ruxolitinib raised EGFR protein level in HEK293T. f JAK-STAT blockage with ruxolitinib mitigates the effect of RanBP6 KD on EGFR protein levels in HEK-293T. Right panel, densitometric analysis of EGFR ratio between Dox+ and Dox− samples for each treatment. Data in bar graphs are represented as mean ± SD (n ≥ 3). Student’s t test: ***p < 0.001; **p < 0.01; ns not significant
