中文摘要：

目的：探讨微小RNA-338．3p（miR-338-3p）对人结直肠癌细胞侵袭迁移能力及Smoothened（SMO）蛋白表达的影响。方法：应用实时荧光定量PCR（Real—timePCR）检测四种人结肠癌细胞系Lovo、HT-29、HCT116、SW620中miR-338—3p表达状况，并以人脐静脉内皮细胞（HUVEC）作为对照。采取脂质体转染miR-338-3p前体（pre—miR-338．3p）至人结直肠癌细胞系SW620，观察细胞转染前后miR-338—3p的表达变化．Transwell侵袭实验及划痕实验检测转染前后细胞侵袭及迁移能力的改变；以Western—blotting和RT-PCR分析sMO蛋白及mRNA表达状况。结果：检测四种结直肠癌细胞系中miR-338—3p表达水平均较正常对照细胞显著降低，差异具有统计学意义（P〈0．01）；SW620细胞转染pre—miR-338—3p后，miR-338—3p表达水平升高，sMO蛋白表达下降，同时肿瘤细胞侵袭、迁移能力明显增强，与对照组相比差异具有统计学意义（P〈0．01）；但SMOmRNA表达水平在转染前后差异无统计学意义（P〉0．05）。结论：MiR-338—3p可通过抑制结直肠癌细胞系中SMO蛋白表达从而抑制肿瘤细胞侵袭转移。

英文摘要：

Objective： To investigate the effects of microRNA-338-3p（miR-338-3p） on cell invasion and migration and Smoothened protein（SMO） expression in human colorectal cancer（CRC） cells. Methods： Real-time polymerase chain reaction（ RT-PCR）was employed to detect the miR-338-3p expression in Lovo, HT-29, HCT116 and SW620, the four types of human CRC cell lines, and in human umbilical vein endothelial cells （HUVEC） , the controls. Human CRC cell line,SW620,was transfected with a miR-338-3p precursor（pre-miR-338-3p） by using liposomes. This allowed determination of the changes in miR-338-3p expression, and CRC cell invasion and migration by Transwell and scratch assays following transfection. Western-blotting and semi-quantitative RT-PCR were adopted to analyze Smoothened（SMO） protein and mRNA expression. Results：Compared with control cells, all human CRC cell lines yielded a significantly attenuated expression of miR-338-3p（ all P 〈 0.01 ）. Transfection of 5W620 cells with pre-miR-338-3p, when compared with control cells ,was associated with augmented miR-338- 3p expression,attenuated SMO protein expression and improved capacity of invasion and migration（ all P 〈 0. 01 ） , but not the expression of SMO mRNA （P 〉 0.05 ）. Conclusion： MiR-338-3p suppresses CRC invasion and migration via inhibiting SMO protein expression.