Synthesis and Biological Evaluation of Quercetagetin Derivatives as the Inhibitors of Mcl-1 and Bcl-2 Against Leukemia.

B-cell lymphoma-2 (Bcl-2) family proteins are fundamental regulators of intrinsic cell apoptosis, and overexpression of apoptotic proteins (Bcl-2 and Mcl-1) is a characteristic of many haematological malignancies. Thus, it is necessary to discover novel inhibitors to treat leukemia. In the current study, we synthesized a series of quercetagetin derivatives (compounds 2a-2t, 3a-3j and 4a-4g) and evaluated their anticancer activities on four leukemia cells (U937, K562, K562R and KG-1). Among those synthesized derivatives, compounds 2a exhibited the best antiproliferative activity (IC(50) = 0.276, 0.159, 0.312 and 0.271 µM to U937, K562, K562R and KG-1, respectively). In addition, 2a induced apoptosis in K562 and markedly arrested the cell cycle G2/M phase of K562. The Western blot assay showed that 2a is a potential inhibitor that can effectively suppress the expression of Bcl-2 and Mcl-1. The molecular docking study predicted that 2a had firm interactions with the active pockets of Bcl-2 and Mcl-1. Finally, in silico pharmacokinetic evaluation of 2a indicated its potential as an anti-leukemia drug lead in the future.