title: Targeting tumor angiogenesis with adenovirus-delivered anti-Tie-2 intrabody.
abstract: Inhibition of tumor angiogenesis is a promising approach for cancer therapy. As an endothelial cell-specific receptor kinase expressed almost exclusively on the surface of vascular endothelium, Tie-2 has an important role in tumor angiogenesis. To explore the therapeutic potential of blocking Tie-2 receptor-interaction pathway, an adenoviral vector was used to deliver a recombinant single-chain antibody fragment rabbit intrabody (pAd-2S03) capable of inhibition of both mouse and human Tie-2 surface expression. pAd-2S03 was given to mice with well-established primary tumors, either a human Kaposi's sarcoma (SLK) or a human colon carcinoma (SW1222). The intrabody significantly inhibited growth of both tumors (75% and 63%, respectively) when compared with pAd-GFP control-treated tumors (P < 0.01). Histopathologic analysis of cryosections taken from mice treated with pAd-2S03 revealed a marked decrease in vessel density, which was reduced by >87% in both tumor models when compared with control-treated tumors (P < 0.01). In contrast, human Tie-2-monospecific pAd-1S05 intrabody did not affect the growth of tumors, indicating that the antitumor effect of pAd-2S03 was due to the inhibition of tumor angiogenesis in these murine models. Our results show that the Tie-2 receptor pathway is essential for both SLK sarcoma and SW1222 colon carcinoma xenograft growth. The present study shows the potential utility of antiangiogenic agents that target the endothelium-specific receptor Tie-2 for down-regulation or genetic deletion.
authors.affiliation: Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Popkov
authors.forename: Nina
authors.initials: N
authors.lastname: Jendreyko
authors.forename: Dorian B
authors.initials: DB
authors.lastname: McGavern
authors.forename: Christoph
authors.initials: C
authors.lastname: Rader
authors.forename: Carlos F
authors.initials: CF
authors.lastname: Barbas
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D048708:Cell Growth Processes / Q000502:physiology; D003110:Colonic Neoplasms / Q000098:blood supply* / Q000628:therapy; D004730:Endothelium, Vascular / Q000473:pathology; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D007128:Immunoglobulin Fragments / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000201:enzymology* / Q000235:genetics / Q000628:therapy*; D011817:Rabbits; D042787:Receptor, TIE-2 / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000378:metabolism; D012514:Sarcoma, Kaposi / Q000098:blood supply* / Q000628:therapy; D023041:Xenograft Model Antitumor Assays
chemical_list: D007128:Immunoglobulin Fragments; D042787:Receptor, TIE-2