Identification of thienopyrimidine derivatives tethered with sulfonamide and other moieties as carbonic anhydrase inhibitors: Design, synthesis and anti-proliferative activity

Eighteen novel compounds harboring the privileged thienopyrimidine scaffold (5a -q, and 6a), were designed based on molecular hybridization strategy. These compounds were synthesized and tested for their inhibitory activity against four different carbonic anhydrase isoforms: CA I, II, IX, and XII. Microwave and conventional techniques were applied for their synthesis. Compounds 5b, 5g, 5l, and 5p showed the highest inhibition activity against the four CA isoforms. Compound 5p exhibited promising inhibitory activity against CA II, CA IX and CA XII with KI values of 8.6, 13.8, and 19 nM, respectively, relative to AAZ, where KIs = 12, 25, and 5.7 nM, respectively. Also, compound 5 l showed significant activity against the tumor -associated isoform CA IX with KI = 16.1 nM. All the newly synthesized compounds were also screened for their anticancer activity against NCI 60 cancer cell lines at a 10 mu M concentration. Compound 5n showed 80.38, 83.95, and 87.39 % growth inhibition against the leukemic cell lines CCRF-CEM, HL -60 (TB), and RPMI-8226, respectively. Also, 5 h showed 87.57 % growth inhibition against breast cancer cell line MDA-MB-468; and 66.58 and 60.95 % inhibition against renal cancer cell lines UO-31, and ACHN, respectively. A molecular docking study was carried out to predict binding modes of our synthesized compounds in the binding pockets of the four carbonic anhydrase isoforms, and results revealed that compounds 5b, 5g, 5l, and 5p succeeded in mimicking the binding mode of AAZ through metal coordination with Zn+2 ion and binding to the amino acids Thr199, His94, and His96 that are critical for activity.