In vivo NIRF imaging-guided delivery of a novel NGR-VEGI fusion protein for targeting tumor vasculature.

Abstract

Pathological angiogenesis is crucial in tumor growth, invasion and metastasis. Previous studies demonstrated that the vascular endothelial growth inhibitor (VEGI), a member of the tumor necrosis factor superfamily, can be used as a potent endogenous inhibitor of tumor angiogenesis. Molecular probes containing the asparagine-glycine-arginine (NGR) sequence can specifically bind to CD13 receptor which is overexpressed on neovasculature and several tumor cells. Near-infrared fluorescence (NIRF) optical imaging for targeting tumor vasculature offers a noninvasive method for early detection of tumor angiogenesis and efficient monitoring of response to anti-tumor vasculature therapy. The aim of this study was to develop a new NIRF imaging probe on the basis of an NGR-VEGI protein for the visualization of tumor vasculature. The NGR-VEGI fusion protein was prepared from prokaryotic expression, and its function was characterized in vitro. The NGR-VEGI protein was then labeled with a Cy5.5 fluorophore to afford Cy5.5-NGR-VEGI probe. Using the NIRF imaging technique, we visualized and quantified the specific delivery of Cy5.5-NGR-VEGI protein to subcutaneous HT-1080 fibrosarcoma tumors in mouse xenografts. The Cy5.5-NGR-VEGI probe exhibited rapid HT-1080 tumor targeting, and highest tumor-to-background contrast at 8 h post-injection (pi). Tumor specificity of Cy5.5-NGR-VEGI was confirmed by effective blocking of tumor uptake in the presence of unlabeled NGR-VEGI (20 mg/kg). Ex vivo NIRF imaging further confirmed in vivo imaging findings, demonstrating that Cy5.5-NGR-VEGI displayed an excellent tumor-to-muscle ratio (18.93 ± 2.88) at 8 h pi for the non-blocking group and significantly reduced ratio (4.92 ± 0.75) for the blocking group. In conclusion, Cy5.5-NGR-VEGI provided highly sensitive, target-specific, and longitudinal imaging of HT-1080 tumors. As a novel theranostic protein, Cy5.5-NGR-VEGI has the potential to improve cancer treatment by targeting tumor vasculature.

• Authors: Wenhui Ma, Guoquan Li, Jing Wang, Weidong Yang, Yingqi Zhang, Peter S Conti, Kai Chen
• Journal: Amino acids (Amino Acids) Vol. 46 Issue 12 Pg. 2721-32 (Dec 2014) ISSN: 1438-2199 [Electronic] Austria
• PMID: 25182731 (Publication Type: Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• CY5.5 cyanine dye
• Carbocyanines
• Fluorescent Dyes
• Molecular Probes
• NGR peptide
• Oligopeptides
• TNFSF15 protein, human
• Tumor Necrosis Factor Ligand Superfamily Member 15

Topics

• Animals
• Apoptosis
• Carbocyanines (chemistry)
• Drug Delivery Systems (instrumentation, methods)
• Female
• Fluorescent Dyes (chemistry)
• Humans
• Mice
• Mice, Nude
• Molecular Imaging
• Molecular Probes (chemistry)
• Neoplasms (chemistry, drug therapy, pathology, physiopathology)
• Neovascularization, Pathologic (drug therapy, pathology, physiopathology)
• Oligopeptides (administration & dosage, chemistry, genetics, metabolism)
• Spectroscopy, Near-Infrared
• Tumor Necrosis Factor Ligand Superfamily Member 15 (administration & dosage, chemistry, genetics, metabolism)