Enhancement of the antiangiogenic activity of interleukin-12 by peptide targeted delivery of the cytokine to alphavbeta3 integrin.

TitleEnhancement of the antiangiogenic activity of interleukin-12 by peptide targeted delivery of the cytokine to alphavbeta3 integrin.
Publication TypeJournal Article
Year of Publication2004
AuthorsDickerson EB, Akhtar N, Steinberg H, Wang Z-Y, Lindstrom MJ, Padilla ML, Auerbach R, Helfand SC
JournalMolecular cancer research : MCR
Date Published2004 Dec
KeywordsAngiogenesis Inhibitors, Animals, Cell Line, Tumor, CHO Cells, Cloning, Molecular, Cricetinae, Flow Cytometry, Integrin alphaVbeta3, Interferon-gamma, Interleukin-12, Mice, Mice, Inbred BALB C, Mice, Inbred DBA, Mice, Knockout, Mice, Transgenic, Necrosis, Neoplasm Transplantation, Neovascularization, Pathologic, Oligopeptides, Peptides, Plasmids, Protein Engineering, Protein Isoforms, Receptors, Interleukin, Receptors, Interleukin-12, Recombinant Fusion Proteins, Recombinant Proteins, Signal Transduction, Time Factors, Transfection

We engineered a fusion protein, mrIL-12vp [mouse recombinant interleukin (IL)-12 linked to vascular peptide], linking the vascular homing peptide CDCRGDCFC (RGD-4C), a ligand for alphavbeta3 integrin, to mrIL-12 to target IL-12 directly to tumor neovasculature. The fusion protein stimulated IFN-gamma production in vitro and in vivo, indicating its biological activity was consistent with mrIL-12. Immunofluorescence techniques showed mrIL-12vp specifically bound to alphavbeta3 integrin-positive cells but not to alphavbeta3 integrin-negative cells. In corneal angiogenesis assays using BALB/c mice treated with either 0.5 microg/mouse/d of mrIL-12vp or mrIL-12 delivered by subcutaneous continuous infusion, mrIL-12vp inhibited corneal neovascularization by 67% compared with only a slight reduction (13%) in angiogenesis in the mrIL-12-treated animals (P = 0.008). IL-12 receptor knockout mice given mrIL-12vp showed a marked decrease in the area of corneal neovascularization compared with mice treated with mrIL-12. These results indicate that mrIL-12vp inhibits angiogenesis through IL-12-dependent and IL-12-independent mechanisms, and its augmented antiangiogenic activity may be due to suppression of endothelial cell signaling pathways by the RGD-4C portion of the fusion protein. Mice injected with NXS2 neuroblastoma cells and treated with mrIL-12vp showed significant suppression of tumor growth compared with mice treated with mrIL-12 (P = 0.03). Mice did not show signs of IL-12 toxicity when treated with mrIL-12vp, although hepatic necrosis was present in mrIL-12-treated mice. Localization of IL-12 to neovasculature significantly enhances the antiangiogenic effect, augments antitumor activity, and decreases toxicity of IL-12, offering a promising strategy for expanding development of IL-12 for treatment of cancer patients.

Alternate JournalMol. Cancer Res.