Fig. 5

Cisplatin sensitivity in Kpnβ1 overexpressing cells. A The IC₅₀ value for cisplatin was determined for HeLa EGFP and HeLa Kpnβ1-EGFP cells. B Cell viability for EGFP and Kpnβ1-EGFP cells was analyzed 48 h after cisplatin treatment via an MTT assay, and results were normalized to the viability of the untreated cells. Results shown for A and B represent the mean ± SEM (*p < 0.05). C PARP cleavage was analyzed as an indication of apoptosis in both EGFP and Kpnβ1-EGFP cells 48 h after cisplatin treatment. GAPDH was used as a control for loading. D Densitometric quantification of C-PARP relative to GAPDH from two independent experiments. E HeLa EGFP and Kpnβ1-EGFP cells were treated with cisplatin for 24 h, followed by western blot analysis to determine the levels of γH2AX, p53, p21 and Mcl-1. GAPDH was used as a control for loading. F Nuclear and cytoplasmic proteins were isolated from HeLa EGFP and Kpnβ1-EGFP cells and p53 and p21 levels determined by western blot analysis. TBP and GAPDH were used to control for even nuclear and cytoplasmic protein loading, respectively. G HeLa EGFP (a) and Kpnβ1-EGFP (b) cells were co-treated with Cisplatin and the p53 inhibitor Pifithrin α, and cell proliferation monitored 24 h later using the MTT assay. H HeLa EGFP (a) and Kpnβ1-EGFP (b) cells were transfected with control (ctl) or p21 siRNA, and 48 h later treated with Cisplatin for 24 h, whereafter cell proliferation was monitored using the MTT assay. Results shown represent the mean ± SEM of experiments (*p < 0.05)