Abstract: Objective To investigate the effect of total flavonoids of Hippophae rhamnoides L.(HTF) on the proliferation and apoptosis of bladder cancer cell line T24 and underlying mechanism. Methods The bladder cancer T24 cells were incubated with different concentrations (25, 50, 100 μg/mL) of HTF for 24 h, then CCK-8 assay, flow cytometry and Western blot were used to detect proliferation, apoptosis and the expression of Bcl-2 and Bax proteins, respectively. The expression of miR-144 was detected by RT-qPCR. miR-144 inhibitors were transfected into T24 cells to construct T24 cells whose expression of miR-144 was knocked down,then 100 μg/mL HTF was used to interfere with the miR-144-knoched down T24 cells. The same methods were used to detect the effects of knocking down of miR-144 on cell proliferation and apoptosis of T24 cell. Results Compared with the control group, different concentrations of HTF reduced the cell A value and the expression of Bcl-2, and increased the apoptosis rate and the expression of Bax. At the same time, the expression of miR-144 (P<0.05) was increased.The A value of T24 cells that knocked down miR-144 and the expression of Bcl-2 protein in the cells was higher than those of control T24 cells(P<0.05), but the apoptosis rate and the expression of Bax protein were lower(P<0.05). After T24 cells that knocked down miR-144 were treated with 100 μg/mL HTF, their A value and the expression of Bcl-2 protein in the cells were higher than those of T24 cells that not knocked down miR-144(P<0.05), but the apoptosis rate and the expression of Bax protein were lower than those of control T24 cells (P<0.05). Conclusions HTF may slow-down the proliferation of bladder cancer cells and speed-up their apoptosis by up-regulating miR-144.

Key words: total flavonoids of Hippophae rhamnoides L., bladder cancer, miR-144, cell proliferation, apoptosis