Fig 2: ERCC6L expression in upregulated in HCC. a Representative pictures of IHC staining on the tissue chip of HCC for ERCC6L. b Chi-square analysis of ERCC6L expression according to the IHC results in HCC tumor and adjacent non-tumor tissue. c Paired HCC tissue IHC scores for 90 patients (tumor versus adjacent non-tumor). d Overall survival of HCC patients with different levels of ERCC6L expression. e. ERCC6L mRNA expression in Hep3B, HuH-7, and SMMC-7721 cells compared to HL-7702 cells, *p < 0.05. All of the expression levels were normalized to β-actin levels. All experiments were carried out at least three independent times

Fig 3: ERCC6L silencing induces cell cycle arrest and apoptosis in HCC cells. a. Cells were transfected with shERCC6L and NC for 24 h. Cell cycle progression was analyzed by PI staining with flow cytometry. The percentage of cells in each stage was quantified. Figures are representative of at least 3 independent experiments. Statistical differences were compared with NC, *p < 0.05. b. After transfected with shERCC6L and NC for 24 h, apoptosis cells were analyzed by Annexin V/FITC and PI staining with flow cytometry and apoptotic rates were quantified. Figures are representative of at least 3 independent experiments. c. Caspase 3/7 activation in SMMC7721 and HuH7 cells 24 h after transfection with shERCC6L or NC. Data are represent the mean ± SD of three independent experiments. *p < 0.05, **p < 0.001, indicates significant differences compared to the NC group

Fig 4: Effect of knockdown ERCC6L expressin on HCC cells proliferation and migration in vitro. a. ERCC6L protein expression in SMMC7721 and HuH-7 cells transfected with shERCC6L or NC, as determined by Western blotting, *p < 0.05. b. ERCC6L mRNA expression was determined by RT-PCR. *p < 0.05. c. Proliferation of SMMC7721 and HuH-7 cells transfected with shERCC6L or NC, as determined by MTT assays, *p < 0.05 compared with NC at the same time point. d The clone formation assay detected cell proliferation after transfecting with ERCC6L shRNA. e. Migration of SMMC7721 and HuH-7 cells transfected with shERCC6L or NC, as determined by Transwell assays, *p < 0.05 compared with the respective NC group. Dot plots represent one of three independent experiments. In the histogram, data are mean ± SD of three experiments

Fig 5: ERCC6L down-regulation inhibit tumor growth in vivo and hypothetical schematic diagram of mechanisms for HCC progression. (a) The mice was inoculated with either SMMC7721 cells stably expression shERCC6L or NC, and the dissected xenograft tumors from each group were photographed. (b) Tumor volume was measured every 5 days, and growth curves were created for each group. *p < 0.05 vs NC group. (c). Tumor weight at the endpoint (30 days). *p < 0.05 vs NC group. (d) The schematic diagram depicted in Fig. 5d has been created by the authors for this publication