Fig. S3.

Activation of the BMP-BMPR-Smad1/5-70S6K pathway conferred resistance to EGFR-TKIs in lung SqCC cells and patients with EGFR mutations. (A–C) The indicated cell lines were treated with erlotinib (1 μM) for 24 h. Cell extracts were immunoblotted to detect the indicated proteins. (D) Cell viability analysis showed that cotreatment with either BMP2 (10 ng/mL) or BMP4 (10 ng/mL) with erlotinib conferred stronger resistance to erlotinib in Beas/2b-L858R (Left) and SH416 (Right) cell lines. Viability at 72 h was calculated as the ratio of drug-treated cells to viable DMSO-treated cells. (E) Representative IHC images of BMPR-II and p70S6K in stained cells.