Knockdown of RPS9 as well as apigenin downregulates CDK1 mRNA at the promoter level.

<p>(A) HT-29 cells were transfected with siRPS9 or siCtrl. After 72 hr, CDK1 mRNA was quantified by real-time RT-PCR. (B) HT-29 cells were transfected with siRPS9 or siCtrl. After 48 hr, the cells were transfected with a reporter plasmid containing CDK1 promoter (pCDK1PF) or an empty plasmid (pGV-B2). After 24 hr, cell lysates were prepared for luciferase assays. (C) HT-29 cells were treated with the indicated concentrations of apigenin for 24 hr, and CDK1 mRNA was quantified by real-time RT-PCR. (D) HT-29 cells were transfected with pCDK1PF or pGV-B2. After 8 hr, the indicated concentrations of apigenin were added to the cells. After 16 hr, cell lysates were prepared for luciferase assays. CT: control, Data are means ± SD (n = 3). *<i>P</i> < 0.05, **<i>P</i> < 0.01 relative to control.