Discovery of novel thiazolopyrimidine derivatives targeting topoisomerase II: Design, synthesis, antiproliferative evaluation, molecular docking and apoptosis inducing activity.

Two new sets of thiazolopyrimidines IIa-h, IVa-d were designed, synthesized, and screened for their anticancer activity against MCF-7 breast cancer adenocarcinoma, HCT116 colorectal cancer, and HepG2 hepatic cancer. The safety of the newly synthesized compounds was tested using normal cells (BJ). Compounds IIa, IId, and IVa showed exceptional cytotoxic activity against both MCF-7 and HepG2, with IC ranges of (24.52-30.22 & 21.49-34.09 μM), respectively, compared to Doxorubicin IC (32.36 & 50.29 μM), respectively. Furthermore, they exhibited significant selectivity towards the tested cancer cells (SI values 1.7-4.4) compared to doxorubicin (SI values 0.8-1.8). Additionally, thiazolopyrimidines IIa, IId, and IVa showed potent topoisomerase II inhibitory activity (IC 1.23, 0.94, and 1.72 μM, respectively) in comparison with reference compound doxorubicin (IC 3.08 μM). Cell cycle analysis showed that the most potent derivative IId induces cell cycle arrest at the G1 phase, leading to inhibition of cell proliferation and apoptosis. Docking study of thiazolopyrimidines IIa, IId, and IVa showed that they could fit well in the pocket in a similar pattern to etoposide, which accounts for their high potency.