Figure 3. Down-regulation of USP5 inhibited cell proliferation and cell cycle progression of ovarian cancer cells. (A) Western blotting analysis of USP5 in 5 ovarian cancer cell lines and a normal human ovarian cell line IOSE80. (B) OVCAR3 and CAOV3 cells were transiently infected with USP5 shRNAs (#1, #2, #3 and #4), control shRNA (NC) or untreated (Control). Western blotting analysis was performed to check the knockdown efficiency of USP5 shRNAs. (C) Proliferation of OVCAR3 and CAOV3 cells expressing NC or USP5 shRNAs (#1, #2) was detected at the indicated time points by CCK-8 assay. (D) Cell cycle distribution of OVCAR3 and CAOV3 was assessed at 48 h after virus infection by PI staining and flow cytometry analysis. Representative graphs and statistical analysis of percentages at different cell cycle stages are shown. (E–G) Nude mice were transplanted with OVCAR3 cells expressing control (NC) or USP5 shRNA (#1). (E) Tumor volume was assessed at the indicated time points in both group (n=6 per group). (F) On 33 days after transplantation, tumors were resected and weighed. (G) Immunohistochemistry staining of PCNA in xenografts. Scale bar: 100 μm. Representative images and statistical analysis of percentages are shown. ***P<0.001.