U-NO2

U-NO2 is a research-stage small molecule inhibitor belonging to the ureido-substituted benzene sulfonamide (USB) class. It is specifically designed to selectively target the tumor-associated carbonic anhydrase (CA) isoforms, Carbonic Anhydrase IX (CA IX) and Carbonic Anhydrase XII (CA XII). These enzymes are critical modulators of the tumor microenvironment, where they regulate pH to facilitate cancer cell survival, proliferation, and metastasis under hypoxic conditions. U-NO2 exerts its inhibitory effect by binding to the catalytic zinc ion within the enzyme's active site via its sulfonamide moiety and interacting with a 'selective pocket' (specifically residue 131), which grants it selectivity over the ubiquitous off-target cytosolic isoform CA II. In preclinical models of breast cancer, including triple-negative (TNBC) and ER-positive subtypes, U-NO2 has demonstrated the ability to inhibit extracellular CA activity and suppress cell growth, migration, and invasion.

Other names

4-nitrophenylureido-benzenesulfonamide