Fig. 6. PBK inhibitor enhances the lethality effect of cisplatin.

a The IC₅₀ values of A2780 and SKOV3 treated with OTS514 for 48 h. Western blot analysis of protein levels of PBK and β-actin in A2780 (b) and SKOV3 (c) cells treated with 20, 50, 100 nM OTS514 for 48 h. d The CCK8 assay determination of relative cell viability in PLKO.1 and sh-PBK A2780 cells treated with or without 20 nM OTS514 for 48 h. e CCK8 assay determination of relative cell viability in A2780 and SKOV3 cells treated with or without 20 nM OTS514 and 1, 5, 10 μg/ml CDDP for 48 h (data are mean ± SEM, *p < 0.05, **p < 0.01, n = 3). f Experimental design of experimental protocols in BALB/c nude mice. Thirty-five-day-old mice were subcutaneously injected with A2780 cells. When the tumor volumes reached 50–200 mm³ at day 49, tumor-bearing mice then received intraperitoneal injection of CDDP (5 mg/kg, every 3 days) or/and oral administration of OTS514 (25 mg/kg, every day). Fifteen days after treatment, the mice were sacrificed to determine tumor volumes and were photographed. g Tumors from each group were shown. h The tumor volumes of each group (data are mean ± SEM, *p < 0.05, **p < 0.01, n = 6)