Effects of increased IGFBP3 on the sensitivity to EGFR-TKIs.

<p>Resistant cells were infected with Ad/IGFBP-3 at MOIs of 0 to 100 PFU/cell for 48 h and IGFBP-3 expression was determined by Western blotting (A) and ELISA (B). (C) HCC827/GR and HCC827/ER cells were treated with the indicated concentration of EGFR-TKIs for 72 h after infection with 100 MOI of Ad/IGFBP-3. (D) HCC827/GR and HCC827/ER cells were treated with 1 µM EGFR-TKIs and 1 µg/mL rh IGFBP-3 for 72 h. Results are representative of at least three independent experiments, and the error bars represent standard deviation (SD). (E and F) Cells were treated with drugs, rh IGFBP-3 or Ad/IGFBP-3 as in panel C and D. After 24 h, cells were harvested and the modulation of EGFR and IGF1R signalling in the indicated cell lines was detected by Western blotting. (G) Control and IGFBP-3 siRNAs (100 nM) were introduced into HCC827 cells, and IGFBP-3 suppression was confirmed by Western blotting. (H) Cell viability was measured using the MTT assay 72 h later.