目的：探讨miRNA let-7i-5p在肾细胞癌（renal cell carcinoma，RCC）组织中的表达水平及其对RCC细胞769-P的增殖、迁移、侵袭和透明质酸结合蛋白4（hyaluronan-binding protein 4，HABP4）表达的影响。方法：利用TCGA RCC数据库及GEO数据库对let-7i-5p在RCC组织中的表达进行meta分析。体外常规培养人RCC细胞769-P并对其进行转染，根据转染物不同分为过表达组（转染let-7i-5p模拟物）、抑制组（转染let-7i-5p抑制物）和对照组（转染NC序列）。采用CCK-8、细胞划痕实验、Transwell实验及WB法检测let-7i-5p对769-P细胞增殖活力、划痕愈合率、穿膜侵袭细胞数及HABP4表达水平的影响。双荧光素酶报告基因实验验证let-7i-5p与HABP4 mRNA的靶向关系。结果：分析TCGA RCC数据库及5个GEO数据集（GSE23085、GSE47582、GSE95385、GSE16441和GSE71302）中数据结果显示，let-7i-5p在RCC组织中的表达水平显著高于正常肾组织（均P<0.05）。体外实验结果显示，与对照组相比，过表达组在24、48及72 h时细胞增殖活力显著升高，而抑制组显著降低（均P<0.01）；过表达组的划痕愈合率（[ 37.276±2.058）% vs（15.663±2.949）% ，P<0.01]和穿膜侵袭细胞数（[ 377.000±34.044）vs（255.667±25.384）个，P<0.01]均显著升高，而抑制组的划痕愈合率（[ 8.791±2.568）% vs（15.663±2.949）%，P<0.05]和穿膜侵袭细胞数（[ 170.333±14.978）vs（255.667±25.384）个，P<0.01]均显著降低。在野生型HABP4-3’URT质粒组中，过表达let-7i-5p可显著抑制细胞的荧光素酶活性（P<0.01）；而在突变型HABP4-3’URT质粒组中，过表达let-7i-5p对细胞的荧光素酶活性无影响（NS，P>0.05）。WB检测结果显示，与对照组相比，过表达组的HABP4和E-cadherin的水平均降低（均P<0.01）、CDK2的水平升高（P<0.01），而抑制组则相反（均P<0.01）。结论：Let-7i-5p在RCC组织中呈高表达，其可能通过靶向HABP4基因来促进769-P细胞的增殖、迁移和侵袭。

Objective: To investigate the expression level of miRNA let-7i-5p in renal cell carcinoma (RCC) tissues and to explore its effect on the proliferation, migration, invasion, and hyaluronan-binding protein 4 (HABP4) expression in human RCC 769-P cells.Methods: A meta-analysis of let-7i-5p expression in RCC tissues was performed using the TCGA RCC database and GEO database.The human RCC 769-P cells were routinely cultured for transfection in vitro, and were divided into three groups according to different transfection materials: overexpression group (transfected with let-7i-5p mimics), inhibition group (transfected with let-7i-5p inhibitors),and control group (transfected with NC sequence). CCK-8, cell scratch test, Transwell assay, and WB method were used to detect the effects of let-7i-5p on the proliferation, scratch healing rate, invaded cell numbers and HABP4 expression in 769-P cells. Dual[1]luciferase reporter gene assay was performed to demonstrate the targeting relationship between let-7i-5p and HABP4. Results: Data analysis of TCGA RCC database and 5 GEO data sets (GSE23085, GSE47582, GSE95385, GSE16441, and GSE71302) showed that the expression level of let-7i-5p was significantly higher in RCC tissues than in normal kidney tissues (all P <0.05). As shown by in vitro experiments, compared with the control group, the cell proliferation activity of the overexpression group was significantly increased at 24, 48, and 72 h, while that of the inhibition group was decreased (all P<0.01). The scratch healing rate [(37.276±2.058)% vs (15.663±2.949)%, P<0.01] and the invaded cell numbers [(377.000±34.044) vs (255.667±25.34), P<0.05] were significantly increased in the overexpression group, while the scratch healing rate [(8.791±2.568) % vs (15.663±2.949) %, P<0.05] and the invaded cell numbers [(170.333±14.978) vs (255.667±25.384), P<0.01] were significantly reduced in the inhibition group. The luciferase activity was significantly inhibited by the overexpression of let-7i-5p in the wild-type HABP4-3'URT plasmid group (P<0.01), while no statistical difference was observed in the mutant HABP4-3'URT plasmid group (P>0.05). WB results showed that compared with the control group, the expression of HABP4 and E-cadherin in the overexpression group was decreased (all P<0.01), and the expression of CDK2 was increased (P<0.01), while the inhibition group showed the opposite trend (all P<0.01). Conclusion: Let-7i-5p is highly expressed in RCC tissues and promotes the proliferation, migration, and invasion of 769-P cells possibly by targeting HABP4.

西南医科大学青年基金资助项目（No. 2018-ZRQN-142；No. 2018-ZRQN-041）