中文摘要：

目的：探讨胶质瘤miR-29a与CDC42表达的相互关系及其对肿瘤细胞侵袭迁移的影响。方法：采用组织微阵列及锁定寡核苷酸原位杂交技术，检测60例不同级别胶质瘤及10例非肿瘤对照脑组织中miR-29a的表达水平，采用qRT-PCR、Westernblot及Transwell培养，分别检测U251及其稳定表达miR-29a和无义对照序列的亚细胞系（U251-miR-29a及U251-scr）miR-29a、CDC42mRNA及蛋白的表达及其迁移和侵袭能力，并分析其相互关系。结果：各级别胶质瘤miR-29a表达水平均显著低于对照脑组织，并随肿瘤级别升高而减少，差异均有统计学意义（P〈0．01）。U251-miR-29a的miR-29a表达量明显高于U251和U251-ser（P〈0．001），其CDC42mRNA和蛋白表达量明显降低（P〈0．05）；CDC42mRNA与其蛋白表达量呈正相关（r=0．834，P〈0．01），而与miR-29a表达量呈负相关（r=-0．979，P〈0．01）。U251-miR-29a的迁移和侵袭能力明显低于U251和U251-scr（P〈0．001），并均与CDC42蛋白表达量呈正相关（r=0．828，P〈0．01）。结论：miR-29a表达水平是评价胶质瘤良恶性的重要参考指标，胶质瘤细胞miR-29a表达异常减少是CDC42上调及迁移侵袭能力增强的重要因素，补充外源性miR-29a可抑制靶基因CDC42表达，阻止其侵袭迁移，提示恶性胶质瘤基因治疗中具有重要的潜在应用价值。

英文摘要：

Objective： This study aimed to investigate the relationship between miR-29a and CDC42 expressions in glioma cells. This study also aimed to determine the effect of miR-29a on CDC42 expression as well as tumor cell migration and invasion. Methods： The expression levels of miR-29a in 10 cases with non-tumor control brain tissues and 60 cases with glioma tissues of four pathological grades were detected by tissue mieroarray and locked-oligonucleotide-probe in situ hybridization. The expression levels of miR-29, CDC42 mRNA, and protein, the migratory and invasive abilities of U251, and also its corresponding miR-29a and scrambled sequences which overexpress the sub-cell lines U251-miR-29a and U251-scr, were determined by quantitative reverse transcription-polymerase chain reaction, Western blot, and Transwell assay. The relationships among these indexes were also analyzed. Results： miR-29a was significantly downregulated in all of the glioma samples and continuously decreased as the malignant grade of the tumors increased. All of the differences between each pair of the four groups were statistically significant （P〈0.01）. U251-miR-29a expressed a significantly higher level of miR-29a （P〈0.001） and lower levels of CDC42 mRNA and protein （P〈0.05） than U251 and U251-scr. The expression level of CDC42 mRNA was negatively correlated with that of miR-29a （r=-0.979, P〈0.01）, but this expression level was positively correlated with that of CDC42 protein （r=0.834, P〈0.01）. The highest migratory and invasive abilities were observed in U251-miR-29a.Such abilities were positively correlated with CDC42 expression level （r=0.828, P〈0.01）. Conclusion： miR-29a could be used as an important marker to assess the malignant degree of gliomas. The aberrant decrease in miR-29a expression resulted in CDC42 upregulation. This decrease also facilitated the migration and invasion of glioma ceils. The overexpression of miR-29a could effectively block CDC42 expression and substantially inhibit the mig