Our bioinformatics analysis indicated that CBX7-associated genes were enriched in cell cycle-related regulators. Moreover, Fusco and colleagues reported that CBX7 bound to the CCNE1 promoter as a multiprotein complex that included HDAC2 and then suppressed CCNE1 expression in mice and HEK293 cells . Thus, we emphasized analyzing the influence of CBX7 on the cell cycle and the mechanism by which CBX7 regulates CCNE1 expression. Flow cytometry analysis showed that the downregulated CBX7 levels promoted G1/S transition, which was halted by the overexpression of CBX7 (Figure 4A). The levels of cyclin E1, CDK2, p53 and p21 were meansured using western blotting (Figure 4B). Depleted CBX7 levels triggered an improvement in cyclin E1 and CDK2 levels, while the restoration of CBX7 expression lead to decreased cyclin E1 and CDK2 expression (Figure 4C). We also found that the expression of CCNE1 was regulated by CBX7 at the transcriptional level (Figure 4D).