目的： 分析miR-185以及细胞分裂周期蛋白42 （CDC42）在骨肉瘤组织和细胞中的表达情况，初步探究miR-185是否通过调控CDC42影响骨肉瘤MG63细胞的增殖与迁移。 方法： 选取2020年1月至2021年1月于衡水市第四人民医院经病理确诊为骨肉瘤的的28例患者的癌组织及癌旁组织，采用免疫组化法检测骨肉瘤组织中CDC42的表达，采用qPCR法检测骨肉瘤组织中miR-185的表达。双荧光素酶报告基因实验验证CDC42基因与miR-185间的靶向关系。根据转染物不同，将MG63细胞分为miR-185 mimic组、miR-NC组、miR-185 inhibitor组、NC-inhibitor组、CDC42组（转染CDC42过表达载体）及阴性对照（NC）组，采用划痕愈合实验、CCK-8法和流式细胞术分别检测miR-185和CDC42表达对MG63细胞迁移、增殖和周期的影响。构建骨肉瘤MG63细胞裸鼠移植瘤模型，采用免疫组化法、qPCR法和WB法检测过表达或敲降miR-185对移植瘤组织中Ki67与CDC42表达的影响。 结果： 与癌旁组织相比，骨肉瘤组织中miR-185表达明显降低，而CDC42表达显著升高（均P<0.01）。CDC42是miR-185的靶基因。与对照组相比，miR-185 mimic组MG63细胞的迁移和增殖能力均受到抑制（均P<0.01），而CDC42组MG63细胞的迁移和增殖能力均升高、细胞周期阻滞于S期（均P<0.01）；与miR-185组相比，miR-185+CDC42组MG63细胞的迁移和增殖能力均升高、S期细胞比例升高（均P<0.01）。与对照组相比，miR-18 5 mimic组移植瘤组织中Ki67、CDC42表达均显著降低（均P<0.01），而miR-185 inhibitor组则相反（均P<0.01）。 结论： 在骨肉瘤组织中，miR-185呈低表达而CDC42呈高表达，miR-185能够通过负调控 CDC42的表达，从而抑制骨肉瘤MG63细胞的增殖和迁移。

Objective: To analyze the expression of miR-185 and cell division cyclin 42 (CDC42) in osteosarcoma tissues and cells, and to preliminarily explore whether miR-185 affects the proliferation and migration of osteosarcoma MG63 cells by regulating CDC42. Methods: The cancer tissues and para-cancerous tissues of 28 patients with osteosarcoma that pathologically confirmed in the Fourth People's Hospital of Hengshui City from January 2020 to January 2021 were collected for this study. Immunohistochemistry was used to detect the expression of CDC42 in osteosarcoma tissues, and qPCR was used to detect the expression of miR-185 in osteosarcoma tissues. Dual-luciferase reporter gene experiment was applied to verify the targeting relationship between CDC42 and miR-185. According to different transfectants, MG63 cells were divided into miR-185 mimic group, miR-NC group, miR-185 inhibitor group, NC-inhibitor group, CDC42 group (transfected with CDC42 over-expression vector), and negative control (NC) group. The effects of miR-185 and CDC42 expression on the migration, proliferation and cell cycle of MG63 cells were detected by scratch healing assay, CCK-8 method and FCM, respectively. A nude mouse xenograft model was constructed by inoculating osteosarcoma MG63 cells. Immunohistochemistry, qPCR and WB methods were used to detect the effects of over-expression or knock-down of miR-185 on the expression of Ki67 and CDC42 in transplanted tumor tissues. Results: Compared with para-cancerous tissues, the expression of miR-185 in osteosarcoma tissues was significantly decreased, while the expression of CDC42 was significantly increased (all P<0.01). CDC42 was verified to be a target gene of miR-185. Compared with the control group, the migration and proliferation of MG63 cells in the miR-185 mimic group were inhibited (all P<0.01), while the migration and proliferation of MG63 cells in the CDC42 group were increased and the cell cycle was arrested in the S phase (all P<0.01). Compared with the miR-185 group, the migration and proliferation abilities of MG63 cells in the miR-185+CDC42 group were promoted, and the proportion of cells in S phase was increased (all P<0.01). Compared with the control group, the expression of Ki67 and CDC42 in the transplanted tumor tissues of miR-185 mimic group was significantly decreased (all P<0.01), while the opposite results were observed in miR-185 inhibitor group (all P<0.01). Conclusion: miR-185 is lowly expressed while CDC42 is highly expressed in osteosarcoma tissues. miR-185 can inhibit the proliferation and migration of osteosarcoma MG63 cells by negatively regulating the expression of CDC42.

R738.1；R730.2