尿激酶受体基因反义RNA转移体系的建立及其在白血病研究中的应用

尿激酶受体 (uPAR)表达与肿瘤 /白血病细胞的侵袭与转移能力明显相关。为探讨逆转录病毒载体介导的uPAR基因反义RNA转移体系在抑制白血病细胞表达uPAR中的价值 ,构建了表达反义uPAR基因的逆转录病毒载体LaCD87SN ,用脂质体转染 交互感染策略建立uPAR基因反义RNA转移体系 ,并以双嗜型aCD87病毒转导U937白血病细胞 ;用PCR分析反义uPAR基因的整合和表达 ;用流式细胞术和明胶酶谱分别检测白血病细胞CD87表达和基质金属蛋白酶 (MMP)活性。结果显示 :通过转染 交互感染获得上清中病毒滴度为 6 .3× 10 5cfu/ml的双嗜型病毒产生细胞Am12 /aCD87;aCD87病毒感染的U937/aCD87细胞内存在aCD87原病毒的整合 ,并高水平表达uPAR基因反义RNA。此外 ,与载体对照的U937/NeoR细胞相比 ,U937/aCD87细胞表面CD87分子表达并无明显降低 ,但其分泌MMP 9的能力显著下降。结论 :逆转录病毒载体介导的反义RNA转移不能有效地下调白血病细胞表面uPAR表达 ,但可能干扰CD87分子与MMP的相互作用。

Establishment of Urokinase Receptor Gene Antisense RNA Transfer System and Its Application in Leukemia Research

Overexpression of urokinase-type plasminogen activator receptor (uPAR) on tumor cell surface is essential for invasion and metastasis in a variety of tumor cells. To establish a retroviral-mediated antisense RNA transfer system of uPAR gene for exploring its function on down-regulation of uPAR expression in leukemia cells, the retroviral vector LaCD87SN was constructed by inserting uPAR gene into LXSN vector in an antisense orientation. An uPAR gene antisense RNA transfer system was established by liposome-mediated transfection in combination with cross infection with retrovirus. Human leukemia cells U937 were transduced with aCD87 amphotropic retrovirus, expressing uPAR antisense RNA, and the U937/aCD87 cells was obtained by G418 selection. The integration and expression of antisense uPAR gene were analyzed by polymerase chain reaction (PCR) assay. The cell surface expression of CD87 and the activities of matrix metalloproteinase (MMP) were assayed by flow cytometry (FCM) and gelatin zymography, respectively. The results showed that the amphotropic retroviral producers Am12/aCD87, which expressed antisense RNA of uPAR gene with a titer of 6.3 x 10(5) cfu/ml in supernatants, were obtained by means of transfection and superinfection. U937/aCD87 cells were established by continuative G418 selection after retrovirus infection. In U937/aCD87 cells, the integrated provirus and the overexpression of antisense uPAR gene was confirmed. Compared with U937/NeoR cells, FCM analysis revealed that CD87 expression on U937/aCD87 cell surface was not downregulated significantly. However, MMP-9 secretion was significantly suppressed in U937/aCD87 cells. In conclusion, although the retroviral-mediated antisense RNA transfer could not efficiently suppress uPAR expression on leukemic cell surface, it may interfere the uPAR-MMP interactions.