中文摘要：

目的研究miR-133a表达对人骨肉瘤细胞增殖及凋亡的影响。方法qPCR检测miR-133a在骨肉瘤细胞及骨肉瘤样本中的本底表达，然后转染miR-133a拟似物至骨肉瘤细胞，检测细胞增殖与凋亡的变化，并通过含Bcl-xL和Mcl-1的3’UTR区的荧光素酶报告基因载体验证miR-133a是否可下调凋亡抑制基因的表达。结果qPCR结果表明，miR-133a在骨肉瘤细胞及样本中的本底表达较正常成骨细胞和组织低，经转染miR-133a后骨肉瘤细胞增殖速度降低，凋亡比例提高。经双荧光素酶报告基因检测及Western Blot验证miR-133a能够下调凋亡抑制基因Bcl-xL和Mcl-1的表达，进而抑制骨肉瘤细胞的增殖并诱导凋亡。结论miR-133a作为抑癌基因在骨肉瘤发生发展中具有抑制作用，为骨肉瘤的预后判断和临床治疗提供了新的潜在靶点。

英文摘要：

Objective To investigate the effects of miR-133a expression on the proliferation and apoptosis of human osteosarcoma cells. Methods The expressions of miR-133a in osteosarcoma cell lines and samples were assayed by qPCR. After transfection of mimic miR-133a to osteosarcoma cells, changes in cell proliferation and apoptosis were detected by MTT and FCM assays. Inhibition of Bel-xL and Mcl-1 might be responsible for the tumor suppressive effect of miR-133a by assay of double fluorescent report gene detection, so as to verify if miR-133a could down-regulate the expression of apoptosis inhibition gene. Results qPCR assay indicated that the expression of miR-133a in osteosarcoma cells and samples was lower than that in normal osteoblast ceils. Following transfection of miR-133a, rate of osteosarcoma cells proliferation decreased, while rate of apoptosis increased. Assay of double fluorescent report gene and Western blot detection indicated that miR-133a could not only down-regulate the expressions of apoptosis inhibition genes （ Bel-xL and Mcl-1 ）, but inhibit the proliferation of osteosarcoma cells and promote apoptosis of the cells involved. Conclusions Being a tumor suppressor gene, miR-133a played an important role in the occuirence and development of osteosarcoma, and for this reason, it might provide a new evidence or potential target for prognosis and treatment of osteosarcoma clinically.