Fig. 3

C/EBPβ promotes cisplatin resistance in ovarian cancer. a The probability of cisplatin resistance in patients with ovarian cancer in the CEBPB-low and CEBPB-high groups (Pearson’s chi-squared test). mRNA and protein levels were analyzed using the TCGA dataset and IHC, respectively. b C/EBPβ expression was detected by western blotting. c Colony formation of the indicated cells after exposure to cisplatin (50 μM) for 12 h. d–g One week after orthotopic inoculation with the indicated cells, mice were treated with cisplatin (5 mg/kg) or vehicle (PBS) intraperitoneally every 4 days (n = 10 per group). Tumor size was monitored by three-dimensional reconstruction of in vivo bioluminescence images (d). Six weeks after tumor inoculation, tumors were excised and weighed (e). The cisplatin-induced tumor reduction rate was calculated as described in the Methods using the following formula: (1 − V_cisplatin/V_PBS) × 100% (f). IHC analysis of C/EBPβ protein levels in xenograft tumor sections collected from mice treated with or without cisplatin. Bar, 25 µm (g). h IHC analysis of C/EBPβ protein in paired tissue sections collected from initial operation and reoperation performed for management of tumor recurrence in the same patient. i Tumor weights from mice treated as described in d–g. Six weeks after tumor inoculation, tumors were excised and weighed. Uncropped images of blots are shown in Supplementary Figure 25. *P < 0.05; **P < 0.01; ***P < 0.001; n.s. not significant