Fluorescence- and spin-labeled carbonic anhydrase inhibitors.

Carbonic anhydrase IX (hCA IX) is a membrane-associated glycoprotein that is observed in many tumor tissues and is strongly overexpressed by hypoxia conditions. Hypoxia is a clinically important tumor parameter and this enzyme can play an important role as a potential marker of hypoxic tumor and as a therapeutic target too. In the last years, Carbonic Anhydrase IX Inhibitors which possess fluorescent probe were largely used for visualize hypoxic tumor cell lines and for understanding the biological roles of hCA IX in acidification of the external matrix. Here we resume the development pathways of such compounds from the design to the final biological evaluation. Furthermore, spin-labeled CAIs were included to have a complete overview of the potentiality of this enzyme as marker of hypoxic tumors.