title: Active adenoviral vascular penetration by targeted formation of heterocellular endothelial-epithelial syncytia.
abstract: The endothelium imposes a structural barrier to the extravasation of systemically delivered oncolytic adenovirus (Ad). Here, we introduced a transendothelial route of delivery in order to increase tumor accumulation of virus particles (vp) beyond that resulting from convection-dependent extravasation alone. This was achieved by engineering an Ad encoding a syncytium-forming protein, gibbon ape leukemia virus (GALV) fusogenic membrane glycoprotein (FMG). The expression of GALV was regulated by a hybrid viral enhancer-human promoter construct comprising the human cytomegalovirus (CMV) immediate-early enhancer and the minimal human endothelial receptor tyrosine kinase promoter ("eTie1"). Endothelial cell-selectivity of the resulting Ad-eTie1-GALV vector was demonstrated by measuring GALV mRNA transcript levels. Furthermore, Ad-eTie1-GALV selectively induced fusion between infected endothelial cells and uninfected epithelial cells in vitro and in vivo, allowing transendothelial virus penetration. Heterofusion of infected endothelium to human embryonic kidney 293 (HEK 293) cells, in mixed in vitro cultures or in murine xenograft models, permitted fusion-dependent transactivation of the replication-deficient Ad-eTie1-GALV, due to enabled access to viral E1 proteins derived from the HEK 293 cytoplasm. These data provide evidence to support our proposed use of GALV to promote Ad penetration through tumor-associated vasculature, an approach that may substantially improve the efficiency of systemic delivery of oncolytic viruses to disseminated tumors.
authors.affiliation: Department of Clinical Pharmacology, University of Oxford, Oxford, UK.
authors.forename: Hannah H
authors.initials: HH
authors.lastname: Chen
authors.forename: Ryan
authors.initials: R
authors.lastname: Cawood
authors.forename: Yasser
authors.initials: Y
authors.lastname: El-Sherbini
authors.forename: Laura
authors.initials: L
authors.lastname: Purdie
authors.forename: Miriam
authors.initials: M
authors.lastname: Bazan-Peregrino
authors.forename: Leonard W
authors.initials: LW
authors.lastname: Seymour
authors.forename: Robert C
authors.initials: RC
authors.lastname: Carlisle
mesh_terms: D000256:Adenoviridae / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000956:Antigens, Viral / Q000235:genetics / Q000378:metabolism; D002459:Cell Fusion / Q000379:methods*; D004730:Endothelium, Vascular / Q000378:metabolism / Q000821:virology; D004742:Enhancer Elements, Genetic; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism; D015726:Giant Cells / Q000166:cytology / Q000378:metabolism*; D057809:HEK293 Cells; D022781:Hepatocytes / Q000166:cytology / Q000378:metabolism / Q000821:virology; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism; D017989:Leukemia Virus, Gibbon Ape / Q000235:genetics*; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D016513:Mice, SCID; D058990:Molecular Targeted Therapy / Q000379:methods*; D009369:Neoplasms / Q000098:blood supply / Q000628:therapy / Q000821:virology; D050130:Oncolytic Virotherapy / Q000379:methods; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D057705:Transendothelial and Transepithelial Migration / Q000235:genetics*; D014183:Transplantation, Heterologous; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D014771:Virion; D014779:Virus Replication / Q000235:genetics
chemical_list: D000956:Antigens, Viral; D017874:Immediate-Early Proteins; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D014764:Viral Proteins; C044582:immediate-early proteins, cytomegalovirus; D020794:Receptor Protein-Tyrosine Kinases