Near-infrared fluorescence imaging of tumor integrin alpha v beta 3 expression with Cy7-labeled RGD multimers
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Published on: January 7, 2019
Yun Wu1, Weibo Cai, Xiaoyuan Chen
1Molecular Imaging Program at Stanford (MIPS), Department of Radiology and Bio-X Program, Stanford University School of Medicine, 1201 Welch Rd, P095, Stanford, CA 94305-5484, USA.
Purpose:
Cell adhesion molecule integrin alpha v beta 3 is an excellent target for tumor interventions because of its unique expression on the surface of several types of solid tumor cells and on almost all sprouting tumor vasculatures. Here, we describe the development of near-infrared (NIR) fluorochrome Cy7-labeled RGD peptides for tumor integrin targeting.
Procedures:
Mono-, di-, and tetrameric RGD peptides were synthesized and conjugated with Cy7. The integrin specificity of these fluorescent probes was tested in vitro for receptor binding assay and fluorescence microscopy and in vivo for subcutaneous U87MG tumor targeting.
Results:
The tetrameric RGD peptide probe with the highest integrin affinity showed the highest tumor activity accumulation and strongest tumor-to-normal tissue contrast. This uptake is integrin-specific as the signal accumulated in the tumor can be effectively blocked by unconjugated RGD peptide antagonist of integrin alpha v beta 3.
Conclusions:
Noninvasive NIR fluorescence imaging is able to detect and semiquantify tumor integrin expression based upon the highly potent tetrameric RGD peptide probe.
Insights
We developed Cy7-labeled RGD peptides for targeting tumor integrins. The tetrameric RGD peptide probe effectively detected and quantified integrin alpha v beta 3 expression in tumors using near-infrared fluorescence imaging.
Area of Science:
- Biomedical Engineering
- Molecular Imaging
- Oncology
Background:
- Integrin alpha v beta 3 is highly expressed on tumor cells and vasculature, making it a prime target for cancer interventions.
- Developing specific probes for integrin alpha v beta 3 can aid in tumor detection and treatment.
Purpose of the Study:
- To develop and evaluate near-infrared (NIR) fluorochrome Cy7-labeled RGD peptides for targeting tumor integrin alpha v beta 3.
- To assess the efficacy of these probes for noninvasive tumor imaging.
Main Methods:
- Synthesis and Cy7 conjugation of mono-, di-, and tetrameric RGD peptides.
- In vitro testing of integrin specificity using receptor binding assays and fluorescence microscopy.
- In vivo evaluation of subcutaneous U87MG tumor targeting in a preclinical model.
Main Results:
- The tetrameric RGD peptide probe exhibited the highest integrin affinity and demonstrated superior tumor accumulation and contrast.
- Tumor uptake of the probe was confirmed to be integrin-specific, as it could be blocked by unconjugated RGD peptide antagonists.
- Successful noninvasive detection and semiquantification of tumor integrin expression were achieved.
Conclusions:
- Noninvasive near-infrared fluorescence imaging with potent tetrameric RGD peptide probes can effectively detect and semiquantify tumor integrin alpha v beta 3 expression.
- This approach holds promise for advancing tumor diagnostics and targeted therapies.
