title: The oncolytic effect of recombinant vesicular stomatitis virus is enhanced by expression of the fusion cytosine deaminase/uracil phosphoribosyltransferase suicide gene.
abstract: Vesicular stomatitis virus (VSV) has recently been demonstrated to exhibit significant oncolytic capabilities against a wide variety of tumor models in vitro and in vivo. To potentially enhance the oncolytic effect, we generated a novel recombinant VSV (rVSV) that expressed the fusion suicide gene Escherichia coli cytosine deaminase (CD)/uracil phosphoribosyltransferase (UPRT). rVSV encoding the CD/UPRT fusion gene (VSV-C:U) exhibited normal growth properties and generated high levels of biologically active CD/UPRT that could catalyze the modification of 5-fluorocytosine into chemotherapeutic 5-fluorouracil (5-FU), which exhibited considerable bystander effect. Intratumoral inoculation of VSV-C:U in the presence of the systemically administered prodrug 5-fluorocytosine produced statistically significant reductions in the malignant growth of syngeneic lymphoma (A20) or mammary carcinoma (TSA) in BALB/c mice compared with rVSV treatments or with control 5-FU alone. Aside from detecting prolonged therapeutic levels of 5-FU in VSV-C:U-treated animals harboring TSA tumors and enhancing bystander killing of tumor cells, we demonstrated marked activation of IFN-gamma-secreting cytotoxic T cells by enzyme-linked immunospot analysis that may have also facilitated tumor killing. In conclusion, the insertion of the fusion CD/UPRT suicide gene potentiates the oncolytic efficiency of VSV by generating a strong bystander effect and by contributing to the activation of the immune system against the tumor without detrimentally altering the kinetics of virus-mediated oncolysis and may be useful in the treatment of malignant disease.
authors.affiliation: Department of Microbiology and Immunology and Sylvester Comprehensive Cancer Center, University of Miami School of Medicine, Miami, Florida 33136, USA.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Porosnicu
authors.forename: Abdul
authors.initials: A
authors.lastname: Mian
authors.forename: Glen N
authors.initials: GN
authors.lastname: Barber
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D043525:Cytosine Deaminase / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005437:Flucytosine / Q000493:pharmacokinetics; D005472:Fluorouracil / Q000493:pharmacokinetics; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D009374:Neoplasms, Experimental / Q000201:enzymology / Q000235:genetics / Q000628:therapy; D010430:Pentosyltransferases / Q000235:genetics* / Q000378:metabolism; D011355:Prodrugs / Q000493:pharmacokinetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014721:Vesicular stomatitis Indiana virus / Q000201:enzymology / Q000235:genetics* / Q000502:physiology; D014779:Virus Replication / Q000502:physiology
chemical_list: D011355:Prodrugs; D011993:Recombinant Fusion Proteins; D005437:Flucytosine; D010430:Pentosyltransferases; C023269:uracil phosphoribosyltransferase; D043525:Cytosine Deaminase; D005472:Fluorouracil