Fig. 1

CRL4^CUL4A/DDB1 is critical for cisplatin resistance and mitochondrial morphology maintenance of OCCs. a Protein expression of DDB1 and CUL4A in normal ovaries and OC tissue samples based on the CPTAC dataset. Raw data were obtained from the OncoLnc database. *p < 0.01, **p < 0.01. The significance of expression level difference was determined using a t-test. b Relative mRNA expression of DDB1 and CUL4A detected by qPCR in COC1/DDP and COC1 cell lines. Data represent mean ± SEM normalized to 18S. *p < 0.01, **p < 0.01, ***p < 0.001. The significance of expression level difference was determined using a t-test. c Relative DDB1 and CUL4A protein expression levels in COC1/DDP and COC1 cell lines detected by Western Blot. GAPDH was used as a loading control. d, e Box-and-whiskers plot showing a relationship between (left panel) DDB1 and (right panel) CUL4A expression and d serous tumor stage and e platinum (Plat) resistance. n = 113 for DDB1 staining (n = 8 for platinum-resistant, n = 105 for platinum-sensitive) n = 120 for CUL4A staining (n = 9 for platinum-resistant, n = 111 for platinum-sensitive). f Immunohistochemical staining analysis of (upper panel) DDB1 and (lower panel) CUL4A expression in tumor cells in Plat-sensitive (Sens) and Plat-resistant (Res) serous tumors. n = 113 for DDB1 staining (n = 8 for platinum-resistant, n = 105 for platinum-sensitive) n = 120 for CUL4A staining (n = 9 for platinum-resistant, n = 111 for platinum-sensitive). g Overall survival (OS) and h Diseases free survival (DFS) in patients with serous ovarian cancer expressing high (>60% positive cells) or low (<60% positive cells) levels of (left) DDB1 or (right) CUL4A. n = 113 for DDB1 staining (n = 8 for platinum-resistant, n = 105 for platinum-sensitive) n = 120 for CUL4A staining (n = 9 for platinum-resistant, n = 111 for platinum-sensitive). i Representative images showing mitochondrial morphology in (upper panel) A2780CP and (lower panel) COC1/DDP cells with CRL4-knockdown by transmission electron microscope assay