title: Herpes simplex virus amplicon delivery of a hypoxia-inducible angiogenic inhibitor blocks capillary formation in hepatocellular carcinoma.
abstract: Tumor hypoxia induces vascular endothelial growth factor (VEGF) expression, which stimulates tumor angiogenesis. The VEGF pathway is inhibited by soluble VEGF receptors (soluble fetal liver kinase-1 [sFlk-1]) that bind VEGF and block its interaction with endothelial cells. Herpes simplex virus (HSV)-derived amplicons are replication-incompetent viruses used for gene delivery. We attempt to attenuate angiogenesis and inhibit hepatoma growth through amplicon-mediated expression of sFlk-1 under hypoxic control. A multimerized hypoxia-responsive enhancer (10xHRE) was cloned upstream of the sFlk-1 gene (10xHRE/sFlk-1). An amplicon expressing 10xHRE/sFlk-1 was genetically engineered (HSV10xHRE/sFlk-1). SK-HEP-1 human hepatoma cells were transduced with HSV10xHRE/sFlk-1 and incubated in normoxia (21% O2) or hypoxia (1% O2). Human umbilical vein endothelial cell assay evaluated capillary inhibition. Western blot assessed sFlk-1 expression. SK-HEP-1 flank tumors (n = 24) in athymic mice were treated with HSV10xHRE/sFlk-1. Media from hypoxic SK-HEP-1 transduced with HSV10xHRE/sFlk-1 yielded an 80% reduction in capillary formation (P < 0.005), whereas normoxic SK-HEP-1 yielded a 25% reduction (P < 0.05). Western blot of SK-HEP-1 transduced with HSV10xHRE/sFlk-1 demonstrated greater sFlk-1 expression in hypoxia vs. normoxia. SK-HEP-1 tumors treated with HSV10xHRE/sFlk-1 yielded a 72% reduction in volume vs. the control group (P < 0.000001). HSV amplicon-mediated delivery of a hypoxia-inducible soluble VEGF receptor substantially reduces new vessel formation and tumor growth in hepatoma.
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Pin
authors.forename: Maura
authors.initials: M
authors.lastname: Reinblatt
authors.forename: William J
authors.initials: WJ
authors.lastname: Bowers
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Federoff
authors.forename: Yuman
authors.initials: Y
authors.lastname: Fong
mesh_terms: D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000098:blood supply*; D015687:Cell Hypoxia; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics; D005822:Genetic Vectors / Q000235:genetics; D018257:Helix-Loop-Helix Motifs / Q000235:genetics; D006801:Humans; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008113:Liver Neoplasms / Q000098:blood supply*; D051379:Mice; D008819:Mice, Nude; D009687:Nuclear Proteins / Q000235:genetics; D040262:Receptors, Vascular Endothelial Growth Factor / Q000378:metabolism; D018139:Simplexvirus / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics
chemical_list: D020533:Angiogenesis Inhibitors; D004268:DNA-Binding Proteins; C497442:HIF1A protein, human; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D014157:Transcription Factors; D040262:Receptors, Vascular Endothelial Growth Factor