VEGF反义RNA促骨髓瘤细胞凋亡及抑制内皮细胞形成血管作用的体外研究

本研究探讨血管内皮细胞生长因子（VEGF）反义RNA对人多发性骨髓瘤细胞系U266增殖、凋亡及内皮细胞ECV304体外血管形成的影响和以VEGF反义RNA进行多发性骨髓瘤（MM）基因治疗的可行性。将VEGF121反向克隆入真核表达质粒pIRES2-EGFP构建重组质粒AS-VEGF，酶切、测序鉴定。用此真核表达重组质粒转染人骨髓瘤细胞系U266，G418筛选获得阳性克隆。RT-PCR、Westernblot法分别检测阳性克隆中VEGFmRNA和蛋白的表达；利用MTT法、流式细胞术检测转染细胞增殖、凋亡的变化；利用基质胶中内皮细胞ECV304的网络形成检测血管形成。结果表明：获得了携带反义VEGF基因的真核表达重组质粒AS-VEGF；VEGF121反义RNA部分阻断了U266细胞中VEGF的表达，转染重组质粒的U266细胞VEGFmRNA和蛋白表达都较对照组细胞有明显减少，细胞的增殖受到抑制，凋亡增加。转染重组质粒的细胞培养上清在基质胶中作用ECV304细胞后的血管形成较对照组亦有明显减少。结论：VEGF反义RNA可以下调VEGF表达，从而抑制骨髓瘤细胞系U266增殖，增加其凋亡并抑制血管形成。

Effect of VEGF Antisense RNA on Inducing Apoptosis of Myeloma Cells and Inhibition of Angiogenesis in Endothelial Cells In Vitro

This study was aimed to investigate the effect of VEGF antisense RNA on proliferation and apoptosis in myeloma cell line U266 as well as on angiogenesis in endothelial cell ECV304, and to explore the feasibility of gene therapy for multiple myeloma using VEGF antisense RNA. The VEGF121 cDNA was inserted into multiple clone site of eukaryotic expression vector pIRES2-EGFP to construct the recombinant plasmid AS-VEGF. Restriction endonuclease analysis and DNA sequencing were used to confirm the reverse orientation of the VEGF cDNA. The recombinant plasmid was transfected into human myeloma cell line U266 and the positive clone was screened by G418. The VEGF mRNA and protein expressions of the positive clone were detected by RT-PCR and Western blot respectively. The viability and apoptosis of U266 cells were observed by MTT assay, flow cytometry. Angiogenesis was tested by network formation of endothelial cells on matrigel. The results indicated that the recombinant plasmid AS-VEGF expressing VEGF antisense RNA were constructed successfully. VEGF expression in U266 cells was blocked partially by VEGF antisense RNA. Expression of VEGF mRNA and protein decreased more significantly in U266 cells transfected by AS-VEGF than that in control group. Then increasing of apoptosis and inhibition of proliferation in U266 cells transfected by AS-VEGF were observed. Vasoformation on matrigel in the supernatants of U266 culture group transfected by AS-VEGF decreased more significantly than that in control group. It is concluded that VEGF antisense RNA can inhibit the expression of VEGF gene in U266 cells, thereby inhibits the proliferation of U266 cells; increases the apoptosis of U266 cells; and inhibits angiogenesis in vitro.