目的探讨膀胱肿瘤细胞株中microRNA-34a(miR-34a)与Notch1的相互作用关系以及过表达miR-34a对T24细胞增殖的影响。方法通过生物信息学软件预测miR-34a与Notch1的作用位点,并通过荧光素酶实验验证两者的直接调控关系。在膀胱癌细胞株T24过表达miR-34a,采用实时定量PCR和蛋白印迹检测Notch1表达水平的变化;分别通过新型四唑氮盐(MTS)实验和流式细胞术检测细胞增殖、凋亡以及细胞周期的变化。结果 T24细胞中荧光素酶报告基因实验显示,miR-34a在膀胱癌细胞中能与报告基因结合,使萤火虫荧光强度减弱(P=0.006)。过表达miR-34a后,T24细胞内源性Notch1的mRNA水平和蛋白水平均明显下调;T24细胞生长明显受抑(P<0.001),并呈现一定时间依赖性;凋亡率增加(P=0.003),G0-G1期细胞显著增多(P=0.002)。结论过表达miR-34a能通过降低靶基因Notch1的表达,抑制膀胱肿瘤细胞的增殖。 Objective To investigate the interaction between microRNA-34a (miR-34a) and Notch1 in bladder tumor cell lines and the effect of overexpression of miR-34a on the proliferation of T24 cells. Methods The bioinformatics software was used to predict the site of interaction between miR-34a and Notch1, and the direct relationship between miR-34a and Notch1 was verified by luciferase assay. MiR-34a was overexpressed in bladder cancer cell line T24, and the changes of Notch1 expression were detected by real-time quantitative PCR and Western blotting. Cell proliferation, apoptosis and cell proliferation were measured by the new tetrazolium salt (MTS) assay and flow cytometry Cycle changes. Results Luciferase reporter assay in T24 cells showed that miR-34a could bind to the reporter gene in bladder cancer cells and the fluorescence intensity of firefly was weakened (P = 0.006). After overexpression of miR-34a, the mRNA and protein levels of endogenous Notch1 in T24 cells were significantly down-regulated. The growth of T24 cells was significantly inhibited (P <0.001) and showed a time-dependent manner. The apoptosis rate was increased (P = 0.003 ), G0-G1 phase cells increased significantly (P = 0.002). Conclusion Overexpression of miR-34a can inhibit the proliferation of bladder tumor cells by decreasing the expression of target gene Notch1.