腺病毒介导的靶向P85和Akt1短发夹RNA对人胃腺癌细胞生长抑制作用的研究

目的 构建靶向P85和蛋白激酶B1(PKB1/Akt1)的短发夹RNA(shRNA)腺病毒载体,研究其对人胃腺癌细胞SGC-7901生长的抑制效果.方法 构建腺病毒载体rAd5-P+A,体外转染SGC-7901细胞后,以实时定量PCR和Western blot分别检测P85和Akt1的mRNA和蛋白质的表达.以噻唑蓝比色分析法(MTT法)和流式细胞法评价转染后胃癌细胞的增殖活性.构建裸鼠皮下荷瘤模型进一步观察rAd5-P+A对SGC-7901细胞生长的抑制效果,并应用原位末端标记技术(TUNEL法)检测肿瘤细胞的凋亡情况.结果 成功构建的rAd5-P+A重组腺病毒载体转染SGC-7901细胞后可显著抑制p85和Akt1的mRNA表达,而P85和Aktl蛋白表达量在转染48 h、72 h后分别下调57.5%、63.7%和67.8%、75.6%,与空白对照组和通用腺病毒对照(rAd5-HK)组相比,差异具有统计学意义(P=0.005,P=0.003).与空白对照组和rAd5-HK组相比,SGC-7901细胞的增殖活性在rAd5-P+A转染后第2天明显下降(P<0.001),且rAd5-P+A转染组进入S期的细胞数减少了5.9%～7.1%,而进入G0/G1期的细胞增加了12.1%～13.7%.裸鼠皮下荷瘤模型治疗实验也显示,rAd5-P+A可抑制胃癌细胞的生长,诱导细胞的凋亡.结论 腺病毒介导的靶向P85和Akt1的shRNA可抑制人胃腺癌细胞的生长,这可能为胃腺癌靶向性联合基因治疗提供新的策略.

Inhibitory effect of adenovirus-mediated short hairpin RNA targeting P85 and Akt1 on growth of human gastric adenocarcinoma cell

Objective To construct a short hairpin RNA (shRNA) adenovirus vector targeting P85 and protein kinase B1 (PKB1/Akt1) and study its effects on the growth of SGC-7901 human gastric adenocareinoma cells. Methods P85 and Aktl shRNA expression frames were subcloned to pGSadeno adenovirus vector with homologous recombination technology to construct pGSadeno-P85 + Akt1 (rAd5-P + A) vector. After screening and amplification, the recombinant adenovirus vector was digested with PacI and transfected into SGC-7901 cells and then its titer and transfection efficiency were detected with fluorescent microscope. P85 and Akt1 mRNA protein expression was identified with real-time PCR and Western blot. The proliferative activity of tumor cells was evaluated with MTr assay and flow cytometry in vitro, rAd5-HK and rAd5-P + A mediated by adenovirus were injected into the established subcutancous SGC-7901 gastric adenocarcinoma in nude mice. During the observation period of 21 days, tumor volume was measured every 3 days to further testify the anti-tumor effect of rAd5-P + A on the SGC-7901 gastric adenocarcinoma cells and cell in situ apoptosis was detected with TUNEL assay. Results The adenovirus vector rAd5-P + A was successfully constructed and it dramatically downregulated P85 and Akt1 mRNA expression in SGC-7901 gastric adenocarcinoma cells. Compared with a control group of SGC-7901 cells and cells transfected with general adenovirus rAd5-HK as control, P85 and Akt1 protein expression 48 h and 72 h after rAd5-P + A transfection was decreased by 57.5% and 63. 7%, 67. 8% and 75.6% with statistical significance(P = 0. 005, P = 0. 003). Cell proliferative activity in rAd5-P + A transfected cells was suppressed from the second day (P <0. 001) and the decreased P85 and Akt1 expression was accompanied by 5.9% -7. 1% decrease of S phase fraction and 12. 1% - 13.7% increase of G0/G1 phase. The tumor volume of rAd5-P + A treated group was smaller than that of the control and rAd.5-HK group with statistical significance (F = 9. 871, P = 0. 025) . Moreover, rAd5-P + A could induce cell in situ apoptosis. Conclusions Adenovirus-mediated targeting P85 and Akt1 shRNA can inhibit the growth of SGC-7901 human gastric adenocarcinoma cells and this may provide a new strategy of combination gene therapy in gastric adenocarcinoma.