Glioma stem cells targeted by oncolytic virus carrying endostatin–angiostatin fusion gene and the expression of its exogenous gene in vitro

The development of the cancer stem cell (CSCs) niche theory has provided a new target for the treatment of gliomas. Gene therapy using oncolytic viral vectors has shown great potential for the therapeutic targeting of CSCs. To explore whether a viral vector carrying an exogenous Endo–Angio fusion gene (VAE) can infect and kill glioma stem cells (GSCs), as well as inhibit their vascular niche in vitro, we have collected surgical specimens of human high-grade glioma (world health organization, WHO Classes III–VI) from which we isolated and cultured GSCs under conditions originally designed for the selective expansion of neural stem cells. Our results demonstrate the following: (1) Four lines of GSCs (isolated from 20 surgical specimens) could grow in suspension, were multipotent, had the ability to self-renew and expressed the neural stem cell markers, CD133 and nestin. (2) VAE could infect GSCs and significantly inhibit their viability. (3) The Endo–Angio fusion gene was expressed in GSCs 48 h after VAE infection and could inhibit the proliferation of human brain microvascular endothelial cells (HBMEC). (4) Residual viable cells lose the ability of self-renewal and adherent differentiation. In conclusion, VAE can significantly inhibit the activity of GSCs in vitro and the expression of exogenous Endo–Angio fusion gene can inhibit HBMEC proliferation. VAE can be used as a novel virus–gene therapy strategy for glioma.

Research highlights
► VAE can infect glioma stem cells (GSCs) and inhibit the viability of GSCs.
► The expression of Endo–Angio gene can be detected in GSCs after VAE infections.
► The exogenous Endo–Angio fusion protein inhibits HBMEC proliferation.
► Residual viable cells lost the ability of self-renewal and adherent differentiation.
► VAE can both lyse tumor cells and induce expression of Endo–Angio gene.