Production of a replicating retroviral vector expressing Reovirus fast protein for cancer gene therapy

Area of Science:

• Virology
• Molecular Biology
• Cancer Gene Therapy

Background:

• Reovirus fusion-associated small transmembrane (FAST) proteins are known to induce syncytium formation.
• Recombinant vectors expressing fusion proteins are being explored for oncolytic virus development.
• Investigating the potential of FAST proteins in cancer gene therapy is a growing area of research.

Purpose of the Study:

• To evaluate the syncytium-inducing capacity of four different reovirus FAST proteins.
• To assess the efficacy of a replication-competent retroviral (RCR) vector expressing FAST proteins for cancer gene therapy.
• To determine the cytotoxicity of the selected FAST protein and its RCR vector in human cancer cell lines.

Main Methods:

• Transfection of Vero cells with plasmids encoding four FAST proteins (ARV, PuV, BroV, RRV).
• Insertion of FAST genes into a murine leukemia virus (MLV)-based RCR vector for enhanced expression.
• Cytotoxicity assays and syncytium formation analysis in human cancer cell lines (HeLa, HT1080, U87) and 293 T cells.

Main Results:

• All four FAST proteins induced syncytium formation in Vero cells to varying degrees.
• The MoMLV-10A1-p10(PuV) RCR vector demonstrated syncytia formation in 293 T cells.
• The p10(PuV) FAST protein and its RCR vector induced significant syncytium formation in HeLa, HT1080, and particularly U87 human cancer cells.
• Viral supernatants from transfected cells also induced syncytia in cancer cell lines, confirming the vector's efficacy.

Conclusions:

• The p10 FAST protein from Pulau virus (PuV) is a potent inducer of syncytium formation.
• The MLV-based RCR vector encoding p10(PuV) is effective in delivering the FAST protein and inducing cell fusion.
• This RCR vector expressing p10(PuV) shows significant potential as a candidate for cancer gene therapy due to its targeted cytotoxicity.