title: Genetic delivery of an immunoRNase by an oncolytic adenovirus enhances anticancer activity.
abstract: Antibody therapy of solid cancers is well established, but suffers from unsatisfactory tumor penetration of large immunoglobulins or from low serum retention of antibody fragments. Oncolytic viruses are in advanced clinical development showing excellent safety, but suboptimal potency due to limited virus spread within tumors. Here, by developing an immunoRNase-encoding oncolytic adenovirus, we combine viral oncolysis with intratumoral genetic delivery of a small antibody-fusion protein for targeted bystander killing of tumor cells (viro-antibody therapy). Specifically, we explore genetic delivery of a small immunoRNase consisting of an EGFR-binding scFv antibody fragment fused to the RNase Onconase (ONC(EGFR)) that induces tumor cell death by RNA degradation after cellular internalization. Onconase is a frog RNase that combines lack of immunogenicity and excellent safety in patients with high tumor killing potency due to its resistance to the human cytosolic RNase inhibitor. We show that ONC(EGFR) expression by oncolytic adenoviruses is feasible with an optimized, replication-dependent gene expression strategy. Virus-encoded ONC(EGFR) induces potent and EGFR-dependent bystander killing of tumor cells. Importantly, the ONC(EGFR)-encoding oncolytic adenovirus showed dramatically increased cytotoxicity specifically to EGFR-positive tumor cells in vitro and significantly enhanced therapeutic activity in a mouse xenograft tumor model. The latter demonstrates that ONC(EGFR) is expressed at levels sufficient to trigger tumor cell killing in vivo. The established ONC(EGFR)-encoding oncolytic adenovirus represents a novel agent for treatment of EGFR-positive tumors. This viro-antibody therapy platform can be further developed for targeted/personalized cancer therapy by exploiting antibody diversity to target further established or emerging tumor markers or combinations thereof.
authors.affiliation: Oncolytic Adenovirus Group, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.
authors.forename: Inés
authors.initials: I
authors.lastname: Fernández-Ulibarri
authors.forename: Katharina
authors.initials: K
authors.lastname: Hammer
authors.forename: Michaela A E
authors.initials: MA
authors.lastname: Arndt
authors.forename: Johanna K
authors.initials: JK
authors.lastname: Kaufmann
authors.forename: Dominik
authors.initials: D
authors.lastname: Dorer
authors.forename: Sarah
authors.initials: S
authors.lastname: Engelhardt
authors.forename: Roland E
authors.initials: RE
authors.lastname: Kontermann
authors.forename: Jochen
authors.initials: J
authors.lastname: Hess
authors.forename: Heike
authors.initials: H
authors.lastname: Allgayer
authors.forename: Jürgen
authors.initials: J
authors.lastname: Krauss
authors.forename: Dirk M
authors.initials: DM
authors.lastname: Nettelbeck
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D000914:Antibodies, Viral; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000378:metabolism*; D045744:Cell Line, Tumor; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors / Q000235:genetics*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D050130:Oncolytic Virotherapy / Q000379:methods; D050504:Oncolytic Viruses / Q000235:genetics*; D012313:RNA / Q000378:metabolism; D012260:Ribonucleases / Q000008:administration & dosage* / Q000378:metabolism*; D014779:Virus Replication / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D000914:Antibodies, Viral; D000970:Antineoplastic Agents; D012313:RNA; C512478:EGFR protein, human; D066246:ErbB Receptors; D012260:Ribonucleases
keywords: EGFR; Onconase; immunoRNase; oncolytic adenovirus; scFv