Efficient gene transfer of VSV-G pseudotyped retroviral vector to human brain tumor

Abstract

A retroviral vector constructed from the murine leukemia virus (MLV) can only express transgenes in cells undergoing mitosis, indicating its suitability as a delivery vehicle for cancer gene therapy. However, the transduction efficiency (TE) of retroviruses embedding endogenous envelope proteins in human cancer cells was found to be unsatisfactory. Recently, several research groups have demonstrated the feasibility of a retroviral vector pseudotyped with a vesicular stomatitis virus G (VSV-G) protein. In this study, the potential of VSV-G pseudotyped MLV-based retrovirus was examined as a delivery vehicle in a variety of human cancer cells including brain tumor cells in vitro and in vivo. The transduction efficiency of the 293T/G/GP/LacZ retrovirus in cell culture was superior in most cancer cells, particularly in brain tumor cells, compared with that of other retroviruses, such as PA317-or PG13-derived. The relative growth rate and phosphatidylserine expression level on the plasma mem-

Bmi-1 over-expression in neural stem/progenitor cells increases proliferation and neurogenesis in culture but has little effect on these functions in vivo

“…Preparation of high-titer virus was carried out by calcium phosphate transfection of BOSC packaging cells (Pear et al, 1993) with the Bmi-MSCV vector. Vesicular stomatitis virus G protein (VSV-G) plasmid was added during transfection to increase the infectivity of the packaged virus (Lee et al, 2001). Cells were allowed to produce virus for 24-48 hours, then cell supernatants were collected, 0.2 micron filtered, and stored at −80°C or used fresh to infect cultured neural stem/progenitor cells.…”

Do lipid rafts mediate virus assembly and pseudotyping?

“…These are pseudotypes. This phenomenon was described first with RNA viruses but examples were soon found in DNA viruses (Huang et al, 1974;Lee et al, 2001;Pastorekova et al, 1992;Witte & Baltimore, 1977). The consequences of sharing envelope proteins include an increased breadth in the virus host range.…”

Engineering Stem Cells for Therapy

“…Retroviral vectors are produced in a manner similar to adenoviruses, but the viral promoter region located within the long-terminal repeat (LTR) region mediates vector integration as well as transcription. Retroviral vectors are able to transduce MSCs with high efficiency [67], and the expression can persist for at least 6 months. Expression can be limited by 'silencing' of the vector, caused by chromatin inactivation by DNA methylation of the…”