抑癌基因Fhit重组腺病毒的构建表达及其在结肠癌细胞中的生物学功能

Construction and Expression of Recombinant Adenovirus Encoding Tumor Suppressor Fhit and Its Biological Function in Colon Cancer Cells

目的:构建携带抑癌基因Fhit的重组腺病毒并通过其研究Fhit蛋白对结直肠癌细胞增殖能力的影响。方法:利用PCR方法从人胎肝文库中克隆Fhit基因片段,Fhit基因PCR产物连入T载体构建重组质粒pMD18T-Fhit。测序正确后,将基因片段导入ptrack-CMV穿梭质粒中,构建重组穿梭载体ptrack-CMV-Fhit。将经PmeⅠ单酶切线性化的ptrack-CMV-Fhit和骨架腺病毒质粒pAdEasy-1共转BJ5183大肠杆菌,使ptrack-CMV-Fhit和pAdEasy-1发生同源重组。经PacI酶切鉴定正确后,将重组腺病毒质粒转染293A细胞获得表达Fhit蛋白的重组腺病毒rAd-Fhit,将获得的重组腺病毒感染结肠癌细胞,采用蛋白印迹法检测外源Fhit蛋白的表达,并进一步观察其对细胞增殖能力的影响。结果:成功构建了携带有Fhit基因的重组腺病毒,且能够在结肠癌细胞中成功表达Fhit蛋白。在结肠癌细胞中,Fhit蛋白明显减弱了结肠癌细胞的增殖能力。结论:在结肠癌细胞中,Fhit基因可能扮演抑癌基因的角色,而表达Fhit的重组腺病毒很可能成为一种结肠癌生物治疗的新策略。

AIM：To construct a recombinant adenovirus carrying Fhit gene,a tumor suppressor in many types of cancer,and to observe its biological function on the proliferation of colon cancer cells.METHODS：Fhit gene was cloned from the fetal liver cDNA library using the PCR method.The PCR product was inserted into the T vector to construct the plasmid pMD18T-Fhit.The Fhit fragment from the pMD18T-Fhit was inserted into the vector ptrack-CMV to construct a shuttle plasmid ptrack-CMV-Fhit.After PmeI digested and linearized process,ptrack-CMV-Fhit was co-transformed into Escherichia coli strain BJ5183 together with the adenovirus backbone vector pAdEasy-1 to generate a recombinant adenovirus plasmid by homologous recombination.The adenovirus plasmid was identified by PacI digestion and transfected into 293A cells to package a recombinant adenovirus which expressed the Fhit protein.Furthermore,the adenovirus rAd-Fhit was infected into colon cancer cells,and the expression of the ectogenic protein was detected by Western blotting.Finally,the proliferation of colon cancer cells was observed in adenovirus-infected cells by the MTT assay.RESULTS：Constructed the recombinant adenovirus encoding Fhit gene and expressed it in colon cancer cells successfully.Detected that the proliferation of colon cancer cells was inhibited obviously in rAd-Fhit-infected cells with comparison to the control groups.CONCLUSION：Fhit may function as a tumor suppressor in colon cancer cells,and the adenovirus-mediated Fhit can be a novel strategy for the colon cancer therapeutics.