1 May 2010 Cy5.5-labeled Affibody molecule for near-infrared fluorescent optical imaging of epidermal growth factor receptor positive tumors
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Abstract
Affibody protein is an engineered protein scaffold with a three-helical bundle structure. Affibody molecules of small size (7 kD) have great potential for targeting overexpressed cancer biomarkers in vivo. To develop an Affibody-based molecular probe for in vivo optical imaging of epidermal growth factor receptor (EGFR) positive tumors, an anti-EGFR Affibody molecule, Ac-Cys-ZEGFR:1907 (7 kD), is site-specifically conjugated with a near-IR fluorescence dye, Cy5.5-mono-maleimide. Using fluorescent microscopy, the binding specificity of the probe Cy5.5-ZEGFR:1907 is checked by a high-EGFR-expressing A431 cell and low-EGFR-expressing MCF7 cells. The binding affinity of Cy5.5-ZEGFR:1907 (KD) to EGFR is 43.6±8.4 nM, as determined by flow cytometry. For an in vivo imaging study, the probe shows fast tumor targeting and good tumor contrast as early as 0.5 h postinjection (p.i.) for A431 tumors, while MCF7 tumors are barely visible. An ex vivo imaging study also demonstrates that Cy5.5-ZEGFR:1907 has high tumor, liver, and kidney uptakes at 24 h p.i.. In conclusion, Cy5.5-ZEGFR:1907 shows good affinity and high specificity to the EGFR. There is rapid achievement of good tumor-to-normal-tissue contrasts of Cy5.5-ZEGFR:1907, thus demonstrating its potential for EGFR-targeted molecular imaging of cancers.
© (2010) Society of Photo-Optical Instrumentation Engineers (SPIE)
Zheng Miao, Zheng Miao, Gang Ren, Gang Ren, Hongguang Liu, Hongguang Liu, Lei Jiang, Lei Jiang, Zhen Cheng, Zhen Cheng, } "Cy5.5-labeled Affibody molecule for near-infrared fluorescent optical imaging of epidermal growth factor receptor positive tumors," Journal of Biomedical Optics 15(3), 036007 (1 May 2010). https://doi.org/10.1117/1.3432738 . Submission:
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