Small Molecule Activators of Pro-apoptotic BAX for Cancer Therapy

描述(由申请人提供)：靶向关键的凋亡调节因子以克服癌细胞的凋亡抵抗是一种非常有吸引力的治疗策略。促细胞凋亡的Bax 是bcl2蛋白家族中的关键成员，该家族由对立的促凋亡和抗凋亡成员组成，在线粒体凋亡途径上决定细胞的生存和死亡。促凋亡的Bax一旦被激活，就会从胞浆转移到线粒体，以执行线粒体外膜的通透性，线粒体膜是线粒体凋亡的“不归路点”。Bax在细胞死亡调控、肿瘤发生和化疗诱导的癌细胞死亡中的作用已经得到了充分的证实。此外，Bax的抑制物，抗凋亡的bcl2成员的显著过表达在癌细胞中是常见的，并有助于肿瘤的发生和化疗耐药。因此，绝大多数癌细胞含有功能正常但被抑制的bax。我们之前发现了调节胞浆Bax激活的Bax触发位点和一个结合到Bax触发位点并诱导Bax激活的小分子，使这个备受瞩目的凋亡靶点能够直接和合理地靶向。在这里，我们建议评估Bax的触发部位作为一种新的药理学策略来重新激活癌细胞死亡的潜力，并在耐药的急性髓系白血病(AML)的背景下，研究Bax激活分子(BAMS)作为有前景的原型治疗药物。具体地说，我们将1)在结合、结构和生化研究中表征新型BAMS，以选择性地结合Bax触发点并诱导Bax激活，2)研究Bax直接激活机制以重新激活Bax介导的人AML细胞和转基因癌细胞的凋亡，3)检测直接Bax激活的治疗效果，在人AML异种移植中以及使用我们新的先导化合物进行体内外毒性研究，以及4)合成新型BAMS用于靶向验证和提高效力、选择性和药理学特性。因此，我们提出了一种结合了合成化学、结构生物学、生物化学、癌细胞生物学和体内疗效研究的多学科方法，以验证一种新的小分子治疗方法来恢复癌细胞死亡，并提供BAMS作为潜在的癌症治疗的先导结构。

DESCRIPTION (provided by applicant): Targeting key apoptosis regulators to overcome the apoptotic resistance of cancer cells is a highly attractive therapeutic strategy. Pro-apoptotic BAX is a critical member of the BCL-2 protein family, which is composed of opposing pro- and anti-apoptotic members that dictate cellular life and death at the mitochondrial apoptotic pathway. Pro-apoptotic BAX, upon activation, translocates from the cytosol to the mitochondria to execute permeabilization of the outer mitochondrial membrane, the "point of no return" for mitochondrial apoptosis. The role of BAX in cell death regulation, tumorigenesis and chemotherapy-induced cancer cell death has been well established. Furthermore, significant overexpression of anti-apoptotic BCL-2 members, the inhibitors of BAX, is common in cancer cells and contributes to tumorigenesis and chemoresistance. Therefore, the vast majority of cancer cells contain functional but suppressed BAX. We previously discovered the BAX trigger site that regulates the activation of cytosolic BAX and a small molecule that binds to the trigger site of BAX and induces BAX activation, enabling the direct and rational targeting of this high-profile apoptotic target. Here, we propose to evaluate the potential of the trigger site of BAX as a novel pharmacological strategy to reactivate cancer cell death and investigate BAX activator molecules (BAMs) as promising prototype therapeutics, in the context of resistant Acute Myeloid Leukemia (AML). Specifically, we will 1) characterize novel BAMs in binding, structural and biochemical studies for binding selectively to the BAX trigger site and induction of BAX activation, 2) investigate the direct activation mechanism of BAX to reactivate BAX-mediated apoptosis in human AML cells and genetically modified cancer cells, 3) examine the therapeutic efficacy of direct BAX activation, in human AML xenografts and in vitro and in vivo toxicity studies, using our novel lead compound and 4) synthesize novel BAMs for target validation and improvement of potency, selectivity and pharmacological properties. Thus, we propose a multidisciplinary approach that combines synthetic chemistry, structural biology, biochemistry, cancer cell biology and in vivo efficacy studies to validate a novel small-molecule therapeutic approach to restore cancer cell death and provide BAMs as potential lead structures for cancer therapeutics.