Detection of vascular endothelial growth factor in colon cancer xenografts using bevacizumab based near infrared fluorophore conjugate

Background: the aim of this study was to develop the near infrared fluorescence (nirf)-based imaging agent for the visualization of vascular endothelial growth factor (vegf) in colon cancer. alexafluor 750 conjugating with bevacizumab,and injected intravenously into nude mice bearing vegf over-expressing ht29 human colorectal cancer. optical imaging was performed at 15 min,24 h and 48 h post injection. immunofluorescences staining of the tumor sections were performed. ht29 colorectal cancer xenografts were clearly visualized with bevacizumab-alexafluor 750. results: ex vivo analysis showed 2.1 ± 0.4%,37.6 ± 6.3% and 38.5 ± 6.2% injected dose/g accumulated in the tumors at 15 min,24 h and 48 h respectively. tumor uptake was significantly decreased in pretreated with excess of bevacizumab (p = 0.002). immunofluorescence analysis showed strong staining of anti-cd 31 antibody around the blood vessels. anti-vegf-a and bevacizumab showed heterogeneous expression throughout the tumor. conclusions: current study successfully detected the vegf expression in ht29 colorectal cancer xenografts,signifying as a potential agent for non-invasive imaging of vegf expression,which may be applied in clinical practice. © 2014 paudyal et al.; licensee biomed central ltd.