CD24在复发性膀胱癌中的表达及其对癌细胞增殖的影响

摘要

目的：分析 CD24在复发性膀胱癌组织中的表达，探讨抑制 CD24表达对膀胱癌细胞增殖的影响。方法：应用免疫组化检测36例复发性膀胱癌组织中 CD24的表达情况，并进行半定量分析。利用脂质体转染法将含有 CD24特异性 siRNA 的真核表达质粒转染至人膀胱癌 BIU －87细胞中，实时定量 PCR 和 Western blot 法检测 BIU －87细胞中 CD24的表达情况改变，MTT 法、Transwells 侵袭实验分别检测下调 CD24的表达后，膀胱癌细胞增殖、侵袭能力发生的变化。并分析细胞中信号转导及转录活化因子（STAT3）、细胞周期蛋白（CyclinD1）、基质金属蛋白酶（MMP －9）的表达变化。结果：CD24在复发性膀胱癌组织中高表达，高级别膀胱癌组织中，阳性率达76．2％。细胞学实验中，经实时定量 PCR 和 Western blot 法证实实验组较对照组细胞CD24 mRNA 转录和蛋白表达水平明显降低。MTT 检测发现实验组较对照组细胞的增殖能力显著下降；Tran-swells 侵袭实验显示实验组的穿膜细胞数显著少于对照组。实验组中 STAT3、CyclinD1、MMP －9表达有明显下降。结论：CD24在复发性膀胱癌中高表达，并与肿瘤的分级呈正相关。体外实验中，抑制 CD24基因表达能显著抑制膀胱癌细胞的增殖和侵袭能力，间接提示 CD24可能参与膀胱癌的复发进程。%Objective:To investigate the expression of CD24 in recurrent bladder cancer,and analyze the effect of CD24 knockdown by siRNA on bladder cancer cell proliferation.Methods:Immunohistochemical staining was per-formed in 36 cases of recurrent bladder cancer,and the intensity of CD24 staining was semi -quantitatively evaluated. We constructed CD24 siRNA plasmids,and then transfected into BIU -87 cells.The mRNA and protein levels ofCD24 expression in the transfected cells were detected using qRT -PCR and Western blot assay.MTT and Transwells assay were applied to observe the proliferation,invasion of BIU -87 cells.We also detected the STAT3,CyclinD1 and MMP -9 using Western blot assay.Results:The CD24 protein had overexpression in recurrent bladder cancer,which positive rate was 76.2% in high grade bladder cancer tissue.In cell research,mRNA and protein levels of CD24 ex-pression in the siRNA group were significantly decreased compared with the control group.The proliferation of CD24 siRNA cells decreased notably compared with the control group,and the number of invasive BIU -87 cells in the siR-NA group decreased compared with the control group.The protein levels of STAT3,CyclinD1 and MMP -9 expression in the siRNA group were also decreased compared with the control group.Conclusion:Expression of CD24 gradually increases in recurrent bladder cancer tissues,and has positive relationship with tumor grade.Downregulation of CD24 by siRNA inhibits bladder cancer cell proliferation,induces apoptosis and hinders its invasive ability in vitro,which reveals CD24 may play a critical role in the recurrence of bladder cancer.