(A) Results of colony formation assay obtained for H1299 cells stably expressing LeGO-Pirh2, control LeGO, Pirh2 shRNA, and scrambled shRNA, both untreated and treated with 10 nM and 25 nM doxorubicine for 3 days. (B) Statistical analysis of the relative colonies numbers for LeGO-Pirh2 versus LeGO control and (C) Pirh2 shRNA versus scrambled shRNA was carried out. Error bars indicate ± SEM within triplicate, *P<0.05 (Student's t-test). (D) The apoptosis rate of Pirh2 shRNA, and scrambled shRNA H1299 cells untreated and treated with 1 μM doxorubicin for 16 hours was determined by Annexin V-FACS analysis.