Figure 5.

Overexpression of HCCR-1 reversed the effect of calcitriol on cell cycle progression-related factors. HeLa S3 cells were treated with 0.1% alcohol (control) or 200 nM calcitriol, transfected with pcDNA3.1 or HCCR-1-pcDNA3.1 as indicated, and cultured for 72 h. (A) Western blot analysis demonstrated that calcitriol-induced p27 and phosphorylated p53 protein expression was blocked by HCCR-1 overexpression. (B) G₁ phase CDKs (CDK2 and CDK4) were upregulated by calcitriol and blocked by HCCR-1 overexpression. (C) G₁ phase cyclins (cyclin D1, cyclin A, and cyclin E) were upregulated by calcitriol and blocked by HCCR-1 overexpression.