Modulation of BAK in Lung Cancer Therapeutics

大多数肺癌患者由于基因改变和对常规治疗的抵抗，预后较差。 心理治疗。开发新的、更有效的药物对于改善慢性粒细胞白血病患者的预后至关重要。 非小细胞肺癌(NSCLC)和小肺癌(SCLC)。BAK是一个关键的多域 Bcl2家族中的促凋亡分子，是细胞凋亡所必需的。因为BAK通常是 一种完整的线粒体膜外膜蛋白，而Bax需要在 作为一种细胞凋亡的刺激，BAK的激活可能更容易处理。BAK同或杂二聚体的形成是 这是诱导细胞凋亡的重要机制。BCL-XL和Mcl-1可以与BAK结合，推测BAK 在‘启动’构象中，其BH3结构域暴露，而在诱导凋亡的细胞中，仅有BH3蛋白 取代抗凋亡异二聚体中的BAK。然后，游离的BAK形成低聚物，从而引发 线粒体外膜的通透性和细胞色素c的释放导致细胞凋亡。 BH3结合口袋位于Bakα2和β3之间，这是设计或筛选的理想位置 BAK激活剂，用于开发潜在的新抗癌药物。我们选择了BH3结构域结合 BAK的口袋(aa75-90)作为使用UCSF DOCK 6.1筛选小分子的对接位置 程序套件和NCI化学图书馆数据库。我们发现了两种新的BAK激活剂(BKA-073和BKA-073 BKA-758)对肺癌细胞具有选择性的诱导凋亡作用 上皮细胞。荧光偏振分析表明BKA-073和BKA-758优先与BAK结合 抑制常数值在纳摩尔水平但不与其他Bcl2家族结合的蛋白质 成员(即BAX或BCL2)。先导化合物BKA-758对小鼠肺癌具有较强的抗肿瘤活性 来自肺癌细胞系或患者来源的异种移植模型。我们假设 BKA(S)可能通过特异性靶向BH3激活肿瘤细胞中BAK的促凋亡功能 结合袋，可抑制肺癌。为了验证这一假设，我们确定了两个 具体目的：(1)确定BAK激动剂(BKA)激活促细胞凋亡的机制(S BAK的功能和诱导人肺癌细胞的凋亡；(2)确定BKA化合物 抑制小肺癌和非小细胞肺癌的体内生长。研究将会 检测BKA在患者来源的异种移植、抗辐射肺癌和基因工程中的效力 肺癌动物模型。确定“动态BH3图谱”是否可预测阿司匹林的抗肿瘤疗效 体内的BKA化合物。基于我们提出的研究，预计新型一流的BAK激动剂 作为一类全新的抗肺癌药物，将被开发用于肺癌的治疗。

Most patients with lung cancer have a poor prognosis due to genetic alterations and resistance to conventional therapy. The development of novel and more effective drugs is critical to improve the prognosis of patients with both non-small cell lung cancer (NSCLC) and small lung cancer (SCLC). BAK is a key multidomain proapoptotic molecule in the Bcl2 family, which is required for apoptotic cell death. Because BAK is normally an integral outer mitochondrial membrane protein, whereas BAX requires translocation from the cytosol after an apoptotic stimulus, BAK activation may be more tractable. The formation of BAK homo- or heterodimers is an important mechanism in the induction of apoptosis. Bcl-XL and Mcl-1 can bind to BAK, which is presumably in a ‘primed’ conformation with its BH3 domain exposed, while in apoptosis-induced cells, a BH3-only protein displaces BAK from the anti-apoptotic heterodimer. The free BAK then forms an oligomer that elicits the permeabilization of the mitochondrial outer membrane and the release of cytochrome c leading to apoptosis. The BH3 binding pocket is located between BAK α2 and β3, which is an ideal site for the design or screening of BAK activators for the development of potential new anti-cancer agents. We chose the BH3 domain binding pocket (aa75-90) of BAK as a docking site for the screening of small molecules using the UCSF DOCK 6.1 program suite and the NCI chemical library database. We discovered two novel BAK activators (BKA-073 and BKA-758) that exhibit selective apoptotic effect in lung cancer cells as compared to normal human bronchial epithelial cells. Fluorescence polarization assay reveals that BKA-073 and BKA-758 preferentially bind to BAK protein with inhibitory constant (Ki) values at nanomolar levels in vitro but do not bind to other Bcl2 family members (i.e. BAX or Bcl2). The lead compound BKA-758 has potent antitumor activity against lung cancer in xenografts derived from lung cancer cell lines or patient-derived xenograft models. We hypothesize that BKA(s) may specifically activate the proapoptotic function of BAK in tumor cells by specifically targeting its BH3 binding pocket, which leads to suppression of lung cancer. To test this hypothesis, we have identified two specific aims: (1) To determine the mechanism(s) by which BAK agonists (BKAs) activate the proapoptotic function of BAK and induce apoptosis in human lung cancer cells; (2) To determine whether BKA compounds suppress the growth of small lung cancer (SCLC) and non-small cell lung cancer (NSCLC) in vivo. Studies will test the potency of BKAs in patient-derived xenografts, radioresistant lung cancer and genetically engineered lung cancer animal models. Determine whether the “dynamic BH3 profiling” predicts the antitumor efficacy of BKA compounds in vivo. Based on our proposed studies, it is expected that novel first-in-class BAK agonists as an entirely new class of anti-lung cancer drugs will be developed for lung cancer therapy.