Novel benzofuran-based sulphonamides as selective carbonic anhydrases IX and XII inhibitors: synthesis and <i>in vitro</i> biological evaluation

Abstract

Pursuing on our efforts toward searching for efficient hCA IX and hCA XII inhibitors, herein we report the design and synthesis of new sets of benzofuran-based sulphonamides (<b>4a</b>,<b>b</b>, <b>5a</b>,<b>b</b>, <b>9a-c</b>, and <b>10a-d</b>), featuring the zinc anchoring benzenesulfonamide moiety linked to a benzofuran tail <i>via</i> a hydrazine or hydrazide linker. All the target benzofurans were examined for their inhibitory activities toward isoforms hCA I, II, IX, and XII. The target tumour-associated hCA IX and XII isoforms were efficiently inhibited with <i>K</i>_Is spanning in ranges 10.0-97.5 and 10.1-71.8 nM, respectively. Interestingly, arylsulfonehydrazones <b>9</b> displayed the best selectivity toward hCA IX and XII over hCA I (SIs: 39.4-250.3 and 26.0-149.9, respectively), and over hCA II (SIs: 19.6-57.1 and 13.0-34.2, respectively). Furthermore, the target benzofurans were assessed for their anti-proliferative activity, according to US-NCI protocol, toward a panel of sixty cancer cell lines. Only benzofurans <b>5b</b> and <b>10b</b> possessed selective and moderate growth inhibitory activity toward certain cancer cell lines.