title: Studies on the Interaction of Tumor-Derived HD5 Alpha Defensins with Adenoviruses and Implications for Oncolytic Adenovirus Therapy.
abstract: Defensins are small antimicrobial peptides capable of neutralizing human adenovirus (HAdV)in vitroby binding capsid proteins and blocking endosomal escape of virus. In humans, the alpha defensin HD5 is produced by specialized epithelial cells of the gastrointestinal and genito-urinary tracts. Here, we demonstrate, using patient biopsy specimens, that HD5 is also expressed as an active, secreted peptide by epithelial ovarian and lung cancer cellsin situThis finding prompted us to study the role of HD5 in infection and spread of replication-competent, oncolytic HAdV type 3 (HAdV3). HAdV3 produces large amounts of penton-dodecahedra (PtDd), virus-like particles, during replication. We have previously shown that PtDd are involved in opening epithelial junctions, thus facilitating lateral spread ofde novo-produced virions. Here, we describe a second function of PtDd, namely, the blocking of HD5. A central tool to prove that viral PtDd neutralize HD5 and support spread of progeny virus was an HAdV3 mutant virus in which formation of PtDd was disabled (mut-Ad3GFP, where GFP is green fluorescent protein). We demonstrated that viral spread of mut-Ad3GFP was blocked by synthetic HD5 whereas that of the wild-type (wt) form (wt-Ad3GFP) was only minimally impacted. In human colon cancer Caco-2 cells, induction of cellular HD5 expression by fibroblast growth factor 9 (FGF9) significantly inhibited viral spread and progeny virus production of mut-Ad3GFP but not of wt-Ad3GFP. Finally, the ectopic expression of HD5 in tumor cells diminished thein vivooncolytic activity of mut-Ad3GFP but not of wt-Ad3GFP. These data suggest a new mechanism of HAdV3 to overcome innate antiviral host responses. Our study has implications for oncolytic adenovirus therapy.IMPORTANCEPreviously, it has been reported that human defensin HD5 inactivates specific human adenoviruses by binding to capsid proteins and blocking endosomal escape of virus. The central new findings described in our manuscript are the following: (i) the discovery of a new mechanism used by human adenovirus serotype 3 to overcome innate antiviral host responses that is based on the capacity of HAdV3 to produce subviral penton-dodecahedral particles that act as decoys for HD5, thus preventing the inactivation of virus progeny produced upon replication; (ii) the demonstration that ectopic HD5 expression in cancer cells decreases the oncolytic efficacy of a serotype 5-based adenovirus vector; and (iii) the demonstration that epithelial ovarian and lung cancers express HD5. The study improves our understanding of how adenoviruses establish infection in epithelial tissues and has implications for cancer therapy with oncolytic adenoviruses.
authors.affiliation: Division of Medical Genetics, University of Washington, Seattle, Washington, USA.|Institut de Biologie Structurale, CNRS/UGA/CEA, Grenoble, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Vragniau
authors.affiliation: Division of Medical Genetics, University of Washington, Seattle, Washington, USA.
authors.forename: Jens-Martin
authors.initials: JM
authors.lastname: Hübner
authors.affiliation: Division of Medical Genetics, University of Washington, Seattle, Washington, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Beidler
authors.affiliation: Division of Medical Genetics, University of Washington, Seattle, Washington, USA.
authors.forename: Sucheol
authors.initials: S
authors.lastname: Gil
authors.affiliation: Division of Medical Genetics, University of Washington, Seattle, Washington, USA.
authors.forename: Kamola
authors.initials: K
authors.lastname: Saydaminova
authors.affiliation: Division of Medical Genetics, University of Washington, Seattle, Washington, USA.
authors.forename: Zhuo-Zhuang
authors.initials: ZZ
authors.lastname: Lu
authors.affiliation: Division of Medical Genetics, University of Washington, Seattle, Washington, USA.
authors.forename: Roma
authors.initials: R
authors.lastname: Yumul
authors.affiliation: Division of Medical Genetics, University of Washington, Seattle, Washington, USA.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Wang
authors.affiliation: Division of Medical Genetics, University of Washington, Seattle, Washington, USA.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Richter
authors.affiliation: Division of Medical Genetics, University of Washington, Seattle, Washington, USA.
authors.forename: Pavel
authors.initials: P
authors.lastname: Sova
authors.affiliation: Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Drescher
authors.affiliation: Institut de Biologie Structurale, CNRS/UGA/CEA, Grenoble, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Fender
authors.affiliation: Division of Medical Genetics, University of Washington, Seattle, Washington, USA lieber00@uw.edu.|Department of Pathology, University of Washington, Seattle, Washington, USA.
authors.forename: André
authors.initials: A
authors.lastname: Lieber
mesh_terms: D000260:Adenoviruses, Human / Q000276:immunology*; D001706:Biopsy; D018938:Caco-2 Cells; D004847:Epithelial Cells / Q000276:immunology* / Q000821:virology*; D005260:Female; D006801:Humans; D057131:Immune Evasion; D008175:Lung Neoplasms / Q000473:pathology; D050130:Oncolytic Virotherapy; D050504:Oncolytic Viruses / Q000276:immunology*; D010051:Ovarian Neoplasms / Q000473:pathology; D023084:alpha-Defensins / Q000378:metabolism*
chemical_list: C500225:DEFA5 protein, human; D023084:alpha-Defensins
keywords: adenovirus; cancer; defensins; innate immunity