中文摘要：

目的：探讨微小RNA let-7i对口腔鳞癌细胞的增殖、凋亡、侵袭及迁移调控的作用。方法：荧光定量PCR（q RT-PCR）检测口腔鳞癌组织与癌旁正常组织之间let-7i的表达差异,并在口腔鳞癌细胞系和正常口腔上皮细胞系中进行表达水平验证。应用let-7i抑制物和模拟物转染口腔鳞癌细胞系（SCC25）细胞,q RT-PCR检测let-7i的抑制或者增强效率;应用细胞增殖实验、单细胞克隆形成实验、细胞凋亡实验、Transwell细胞迁移和侵袭实验等技术,分别检测let-7i表达水平变化对口腔鳞癌细胞生长、迁移和侵袭等生物学行为的影响。结果：与癌旁正常组织相比,口腔鳞癌组织中let-7i的表达显著上调,为癌旁正常组织表达量的1.97倍;let-7i抑制物和模拟物,能分别显著降低或增强SCC25中let-7i的表达;降低let-7i表达后,SCC25细胞的增殖能力、迁移和侵袭能力明显降低;而细胞凋亡率明显升高;相反let-7i表达升高后,SCC25细胞增殖能力、Transwell迁移和侵袭能力明显升高,而凋亡率明显降低。结论：let-7i能够促进口腔鳞癌细胞的增殖、迁移和侵袭,而其抑制物能发挥有效的抗增殖作用,为口腔鳞癌的靶向治疗提供了候选分子。

英文摘要：

Objective： To investigate the regulation of let-7i on the cell proliferation,apoptosis,migration and invasion in oral squamous cell carcinoma（ OSCC）. Methods： The expressions of let-7i were measured in OSCC tissues,the adjacent normal tissues and OSCC cell lines by q RT-PCR to investigate the differentiation of paired samples. The inhibition or enhancement of let-7i in OSCC cells after let-7i inhibitor or let-7i mimics were transfected into the cells. Then cell proliferation,single cell clone formation,flow cytometry,transwell migration and invasion tests were carried out to study the effects of let-7i on biological behaviors of OSCC cells. Results： The expression of let-7i increased in OSCC tissues（ n = 29,t = 8. 215,P〈0. 01） and cell lines compared with adjacent normal tissues. Let-7i inhibitor or mimics could decrease or enhance the expressions of let-7i in SCC25 cells significantly. After let-7i inhibitor was transfected,the cell proliferation,cell migration and invasion abilities of SCC25 cells were reduced significantly,and higher apoptotic rate was observed. Instead,when transfected with let-7i mimics,SCC25 cells showed an opposite change on biological behaviors. Conclusions： Let-7i can promote the cell proliferation,migration and invasion in OSCCs. As let-7i inhibitor is an effective anticancer factor by interfering with let-7i,providing us a novel candidate to treat OSCCs.