Department of Geriatrics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
Biotechnol Appl Biochem. 2021 Feb;68(1):82-91. doi: 10.1002/bab.1896. Epub 2020 Feb 24.
Akt, a serine-threonine protein kinase, is regulated by class-I PI3K signaling. Akt regulates a wide variety of cell processes including cell proliferation, survival, and angiogenesis through serine/threonine phosphorylation of downstream targets including mTOR and glycogen-synthase-kinase-3-beta (GSK3β). Targeting cancer-specific overexpression of Akt protein could be an efficient way to control cancer-cell proliferation. However, the ATP-competitive inhibitors are challenged by the highly conserved ATP binding site, and by competition with high cellular concentrations of ATP. We previously developed an allosteric inhibitor, 2-arylidene-4, 7-dimethyl indan-1-one (FXY-1) that showed promising activity against several lung cancer models. In this work, we designed a congeneric series of molecules based on FXY-1 and optimized lead based on computational, in vitro assays. Computational screening followed by enzyme-inhibition and cell-proliferation assays identified a derivative (FCX-146) as a new lead molecule with threefold greater potency than the parent compound. FCX-146 increased apoptosis in HL-60 cells, mediated in part through decreased expression of antiapoptotic Bcl-2 protein and increased levels of Bax-2 and Caspase-3. Molecular-dynamic simulations showed stable binding of FCX-146 to an allosteric (i.e., noncatalytic) pocket in Akt. Together, we propose FCX-146 as a potent second-generation arylidene indanone compound that binds to the allosteric pocket of Akt and potently inhibits its activation.
Akt 是一种丝氨酸/苏氨酸蛋白激酶，受 I 类 PI3K 信号通路调节。Akt 通过丝氨酸/苏氨酸磷酸化下游靶标（包括 mTOR 和糖原合成酶激酶-3β（GSK3β））来调节多种细胞过程，包括细胞增殖、存活和血管生成。针对 Akt 蛋白的癌症特异性过表达进行靶向治疗可能是控制癌细胞增殖的有效方法。然而，ATP 竞争性抑制剂受到高度保守的 ATP 结合位点和与细胞内高浓度 ATP 的竞争的挑战。我们之前开发了一种别构抑制剂，2-芳基亚甲基-4,7-二甲基茚满-1-酮（FXY-1），它对几种肺癌模型表现出有希望的活性。在这项工作中，我们设计了基于 FXY-1 的同系物系列分子，并基于计算、体外测定优化了先导化合物。计算筛选后进行酶抑制和细胞增殖测定，确定了一种衍生物（FCX-146）作为新的先导分子，其效力比母体化合物高三倍。FCX-146 增加 HL-60 细胞的凋亡，部分通过降低抗凋亡 Bcl-2 蛋白的表达和增加 Bax-2 和 Caspase-3 的水平来介导。分子动力学模拟显示 FCX-146 稳定结合 Akt 的别构（即非催化）口袋。总之，我们提出 FCX-146 是一种有效的第二代芳基亚甲基茚满酮化合物，它与 Akt 的别构口袋结合并能强烈抑制其激活。
