Construction of a replication-competent retroviral vector for expression of the VSV-G envelope glycoprotein for cancer gene therapy

In this study, a Moloney murine leukemia virus-gibbon ape leukemia virus (MoMLV-GALV) vector was constructed by replacing the naturalenv gene of the full-length Moloney MLV genome with the GALVenv gene. To monitor viral transmission by green fluorescent protein (GFP) expression, internal ribosomal entry site-enhanced GFP (IRES-EGFP) was positioned between the GALVenv gene and the 3 ’ untranslated region (3’ UTR) to obtain pMoMLV-GALV-EGFP. The MoMLV-GALV-EGFP vector was able to replicate with high titer in TE671 human rhabdomyosarcoma cells and U-87 human glioma cells. To evaluate the potential of the MoMLV-GALV vector as a therapeutic agent, the gene for the fusogenic env elope G glycoprotein of vesicular stomatitis virus (VSV-G) was incorporated into the vector. Infection with the resulting MoMLV-GALV-VSV-G vector resulted in lysis of the U-87 cells due to syncytium formation. Syncytium formation was also observed in the transfected human prostate cancer cell line L NCaP after extended cultivation of cells. In addition, we deleted the GALVenv gene from the MoMLV-GALV-VSV-G vector to improve viral genome stability. This MoMLV-VSV-G vector is also replication competent and induces syncytium formation in 293T, HT1080, TE671 and U-87 cells. These results suggest that replication of the MoMLV-GALV-VSV-G vector or MoMLV-VSV-G vector may directly lead to cytotoxicity. Therefore, the vectors developed in this study are potentially useful tools for cancer gene therapy.
Source: Archives of Virology - Category: Virology Source Type: research