Mechanism assay of interaction between blood vessels-near infrared probe and cell surface marker proteins of endothelial cells

In vivo blood vessels imaging is crucial to study blood vessels related diseases in real-time. For this purpose, fluorescent based imaging is one of the utmost techniques for imaging a living system. The discovery of a new near-infrared probe (CyA-B2) by screening chemical probe library in our previous report which showed the most specific binding on the blood capillaries of the 3D-tissue models give us interest to study more about the binding site of this probe to the surface of endothelial cells main component cell of blood capillaries. By studying the competition assays of CyA-B2 using several potential surface markers of endothelial cells found through the chemical database (ChEMBL) and manually selected, CD133 gave the lowest IC50 (half maximal inhibitory concentration) value. Hence, CD133 protein which is expressed on the endothelial cell membrane was postulated to be the binding site due to the suppression of CyA-B2 on the blood capillaries by the competition assays. Since, CD133 is also expressed on many types of cancer cells, it would be useful to use CyA-B2 as a bioprobe to monitor or diagnostic tumor growth.

Automated summary

In vivo blood vessels imaging plays a crucial role in studying blood vessel-related diseases, and fluorescent-based imaging is an effective technique for real-time imaging. A new near-infrared probe (CyA-B2) was discovered in a previous study, which showed specific binding to the blood capillaries in 3D tissue models. Through competition assays, CD133 protein was found to have the strongest binding to CyA-B2, suggesting it as the binding site on the surface of endothelial cells. Since CD133 is also expressed on various cancer cells, CyA-B2 could be useful as a bioprobe for monitoring or diagnosing tumor growth.