Fig 2: DHRS2 downregulates ERCC1 in a p53-dependent manner. (A) The effect of DHRS2 knockdown on the expression of p53 protein. (B) The effect of p53 knockdown on the expression of ERCC1 protein. *P<0.05. DHRS2, dehydrogenase/reductase SDR family member 2; ERCC1, excision repair cross-complementing group 1; Oxa, oxaliplatin.

Fig 3: Slug and ERCC1 are upregulated in CRC tissues and predict poor survival of patients. (A, C) Representative immunohistochemical staining of Slug (A) and ERCC1 (C) in CRC tumor sample and normal tissue sample. (B, D) Scores for Slug (B) and ERCC1 (D) staining in 74 tumor tissue and 40 adjacent normal tissue samples from CRC patients. (E) Slug expression associates with tumor size in CRC patients in GSE39582 from the GEO database. (F) Association with Slug expression and lymph node metastasis in CRC patients in GSE39582 from the GEO database. N0: no lymph node metastasis; N1: lymph node metastasis. (G) The relative expression of Slug in stage I, II, III, and IV CRC patients based on data available in GSE39582 from the GEO database. (H) Slug expression associates with Duke stage grade in CRC patients in GSE14333 from the GEO database. (I, J) Impact of Slug and ERCC1 mRNA expression on overall survival in CRC patients in GSE14333 from the GEO database. (K) Univariate survival analysis of overall survival in 74 CRC patients as determined by Kaplan–Meier plot estimates based on Slug protein expression. *p < 0.05, **p < 0.01.

Fig 4: Cell transfection efficiency analyses by RT-qPCR and western blotting (A) Protein expression level of ERCC1 in the NCI-H1299 cell line, measured by western blotting analysis. (B) Gray analysis of the western blotting for the NCI-H1299 cell line. *P<0.05vs. siRNA-NC group. (C) mRNA expression level of ERCC1 in the NCI-H1299 cell line. (D) mRNA expression level of ERCC1 in the SK-MES-1 cell line. *P<0.05 vs. GV230 group; #P<0.05 vs. siRNA-NC group. ERCC1, ERCC excision repair 1 endonuclease non-catalytic subunit; si, small interfering; NC, negative control; RT-q, reverse transcription-quantitative.

Fig 5: Effects of ERCC1 on the apoptosis of NCI-H1299 cells treated with cisplatin and olaparib. (A) Representative flow cytometry images. (B) Cell apoptosis rate in different groups of treated cells. *P<0.05 vs. GV230 group; #P<0.05 vs. siRNA-ERCC1 group. ERCC1, ERCC excision repair 1 endonuclease non-catalytic subunit; si, small interfering; NC, negative control; PI, propidium iodide.