腺病毒介导PTEN过表达抑制人脑胶质瘤U251细胞裸鼠移植瘤的生长

Adenovirus-mediated over-expression of PTEN inhibits the growth of human glioma U251 cell xenografts in nude mice

目的:研究含第10号染色体同源丢失性磷酸酶-张力蛋白(phosphatase and tensin homologue deleted on chromo-some 10,PTEN)基因的重组腺病毒(Ad-PTEN-GFP)对人胶质瘤U251细胞裸鼠移植瘤生长的抑制作用。方法:于裸鼠背部注射人脑胶质瘤U251细胞,建立胶质瘤裸鼠移植瘤模型。荷瘤裸鼠随机分为3组进行治疗:Ad-PTEN-GFP组,Ad-GFP组(空载体组)及PBS组(空白组),观察3组裸鼠移植瘤的生长,测量肿瘤体积,绘制肿瘤生长曲线,并观察荷瘤裸鼠的生存时间。采用TUNEL法检测移植瘤组织中细胞凋亡的情况,采用免疫组化法检测移植瘤组织中PTEN及P65蛋白的表达。结果:与Ad-GFP组相比,Ad-PTEN-GFP组移植瘤的生长受到抑制,肿瘤体积抑制率显著升高[(82.5±12.7)%vs(7.2±1.3)%,P<0.05],荷瘤裸鼠生存时间延长[(103±10)vs(58±8)d,P<0.01];TUNEL结果表明,Ad-PTEN-GFP组与Ad-GFP组相比,移植瘤细胞凋亡率明显增加[(46.4±8.3)%vs(4.6±1.0)%,P<0.01];免疫组化结果显示,Ad-PTEN-GFP组与Ad-GFP组相比,移植瘤组织中PTEN蛋白的阳性表达率增高(83.3%vs 0,P<0.01),P65蛋白阳性表达率下降(16.7%vs 66.7%,P<0.01)。结论:感染Ad-PTEN-GFP后人脑胶质瘤U251细胞裸鼠移植瘤的生长受到抑制,其机制可能与P65蛋白表达的下调有关。

Objective：To investigate the inhibitory effect of recombinant adenovirus （Ad-PTEN-GFP） containing phosphatase and tensin homologue deleted on chromosome 10 （PTEN） gene on the growth of human glioma U251 cell xenografts in nude mice. Methods： Human glioma U251 cells were injected under the skin of the dorsum to establish a nude mouse glioma model. The tumor-bearing nude mice were randomly divided into three groups： Ad-PTEN-GFP group,Ad-GFP group （empty vector group） and PBS group （blank group）.The growth of tumor xenografts in nude mice of the three groups was observed. The tumor volumes were measured, the tumor growth curves were drawn and the survival time of the nude mice bearing tumors was observed. The cell apoptosis of tumor cells was detected by TUNEL assay, and the expressions of PTEN and P65 proteins in tumor tissues were detected by immunohistochemical assay. Results： Compared with the Ad-GFP group, the growth of glioma cell xenografts in the Ad-PTEN-GFP group was inhibited with tumor volume inhibition rate increasing significantly （／[82.5±12.7／]% vs ／[72±1.3／]%, P〈0.05）, and the survival time of tumor-bearing nude mice was prolonged （／[103±10／] vs ／[58±8／] d, P〈0.01／]. TUNEL assay results showed that the apoptotic rate of glioma cells was significantly increased （／[46.4±8.3／]% vs ／[4.6±1.0／]%, P〈0.01／]. Immunohistochemical assay results showed that the positive expression rate of PTEN protein was increased in the Ad-PTEN-GFP group compared with the Ad-GFP group （83.3% vs 0, P〈0.01）, and the positive expression rate of P65 protein was decreased （16.7% vs 66.7%, P〈0.01）. Conclusion： The growth of human glioma U251 cell xenografts in nude mice is suppressed after Ad-PTEN-GFP infection, which may be related with the down-regulation of P65 protein expression.