Figure 7.

CAPN2 regulates gefitinib-resistance via the EGFR/AKT/survivin signal pathway. (A) Heatmap of downstream CAPN2 target proteins determined by a whole human cDNA array. (B) EGFR, pAKT, AKT, survivin and KRT5 protein expression was measured by western blotting. (C) CDKN1A, GADD45A, CDK1 and CDK2 gene expression was measured by reverse transcription-quantitative polymerase chain reaction. *P<0.05 vs. negative control. (D) The viability of PC9R cells transfected with EGFR overexpressing vector and/or shCAPN-1 in the presence of various concentrations of gefitinib was determined by cell counting kit-8 assay. Viability of PC9R cells following transfection with shNEG, shCAPN2-1 or shCAPN2-2, followed by incubation with (E) 20 µM LY294002 (a phosphoinositide 3-kinase/AKT inhibitor) or (F) 10 nM YM155 (a survivin inhibitor). *P<0.05 between two groups. CAPN2, calpain 2; sh, short hairpin RNA; NEG, negative control; EGFR, epidermal growth factor receptor; AKT, protein kinase B; KRT5, keratin-5; CDKN1A, cyclin-dependent kinase inhibitor 1A; GADD45A, growth arrest and DNA damage inducible α; CDK, cyclin-dependent kinase.