Study on the effect of BMSCs-EGFP-tk as mediator of HSV1-tk/GCV suicide gene therapy directed against A549 in vitro

This study aims to observe the expression of HSV1-tk in mouse bone marrow mesenchymal stem cells (BMSCs-EGFP-tk) and detect the inhibition and killing effects of BMSCs as mediator of HSV1-tk/GCV on A549 cells in vitro, which can provide the experimental basis for gene therapy of lung cancer. We constructed the recombinant plasmid Vector pDON-AI-2 Neo-HSV1-tk-IRES2-EGFP with genetic engineering methods. Then we obtained the virus-like particles with infection ability after packaging the virus. The recombinant plasmid was transfected into mouse bone marrow mesenchymal stem cells in vitro. The expressions of EGFP in cells were observed by fluorescence microscopy and HSV1-tk gene was detected with RT-PCR. At last, the A549 cells and BMSCs-EGFP-tk cells were co-cultured with in vitro contact method, and the effect of BMSCs-EGFP-tk/GCV system was determined by MTT. Results indicated that the biological characteristics of BMSCs-EGFP-tk were consistent with those of BMSCs and fluorescent light expression and HSV1-tk gene expression can persist at least 15 days. The A549 cells and BMSCs-EGFP-tk cells were co-cultured and BMSCs-EGFP-tk: A549 = 2: 1, adding 1 mu g/mL GCV, the theory mortality is 58.44%, but actually the mortality is 90%. There is almost no difference between BMSCs-EGFP-tk and BMSCs cells in biological characteristics. The growth of A549 cells have an obviously inhibition and the bystander effect is outstanding in vitro after co-culture and this experiment lays solid foundation for the future research.