Targeted Small Molecule Inhibitors for Inv(16) Leukemia

编码cbfβ(Cbfb)的基因被16号染色体倒位破坏[inv(16)(P13q22)]， 与人类约10%的急性髓系白血病(AML)相关，导致转录因子融合 含大部分CBFβ的蛋白与肌球蛋白重链卷曲尾区融合 (SMMHC)。CbFβ-SMMHC融合蛋白是CbF功能的显性抑制因子，结合RUNX1和 正常造血所需的多个基因表达失调。当前的处理利用 细胞毒性化疗导致55%的五年总存活率，但只有17%的老年患者。这些数据 明确表明靶向治疗可以改善inv(16)AML患者的治疗反应， 尤其是那些已经复发或有复发风险的人，是至关重要的。新兴的文学作品表明 无法用目前的疗法治愈癌症可能归因于癌症干细胞或癌症的数量 具有长期自我更新潜力并能完全概括肿瘤表型的启动细胞 旧病复发。Inv(16)AML就是这种失败的一个很好的例子，因为Inv(16)患者总是在 复发，inv(16)重排，而在诊断时检测到的其他突变(RAS、FLT3ITD或KIT)可能或 可能检测不到。我们的假设是，CBFβ-SMMHC与RUNX1结合的小分子抑制剂 可能是有效的治疗药物，可以根除inv(16)白血病中的白血病起始细胞群， 从而获得更好的长期生存。最近我们开发了第一代抑制剂，它针对的是 CBFβ-SMMHC与RUNX1的蛋白质相互作用在本申请中，我们提出了两个目标： 目的1：优化脑血流量β-SMMHC抑制剂，以提高药效和ADMET性能。我们 建议对我们的第一代抑制剂进行修改，以改善ADMET的性能，以开发出一种有效的口服药物 用于治疗inv(16)白血病的生物可用抑制剂。具体地说，我们建议修改 在我们开发的二价抑制剂中，通过取代基于五元杂环的连接物来连接 提高抑制剂的溶解度和口服生物利用度。最有希望的化合物将被剖析 用于小鼠和大鼠的药代动力学特性，以及使用一组体外ADMET特性。最多的 有希望的化合物将在AIM 2中进行体内有效性和对INV(16)患者样本的有效性测试。 目的2：用急性髓系白血病患者细胞和小鼠模型表征有前景的脑血流β-SMMHC抑制剂 用于inv(16)AML。我们建议确定最有希望的抑制剂在降低 Inv(16)AML与非inv(16)AML患者样本的体外存活率比较。我们还建议确定 它们在小鼠身上的疗效，利用基因工程模型(GEM)和患者来源的体内治疗 异种移植(PDX)小鼠模型的研究。这些抑制剂将接受测试，以确定它们的 抗白血病活性在减少植入、白血病潜伏期和白血病负担以及消除 受体小鼠体内的白血病干细胞。

The gene encoding CBFβ (CBFB) is disrupted by the chromosome 16 inversion [inv(16)(p13q22)], associated with ~10% of acute myeloid leukemia (AML) in humans, resulting in a transcription factor fusion protein containing most of CBFβ fused to the coiled-coil tail region of smooth muscle myosin heavy chain (SMMHC). The CBFβ-SMMHC fusion protein acts as a dominant repressor of CBF function, binding RUNX1 and dysregulating the expression of multiple genes required for normal hematopoiesis. Current treatment utilizing cytotoxic chemotherapy results in 55% five year overall survival but only 17% for older patients. These data clearly indicate that targeted therapies that can improve the therapeutic response for inv(16) AML patients, particularly those who have relapsed or are at risk of relapse, is essential. Emerging literature suggests that inability to cure cancers with current therapies may be attributed to a population of cancer stem cells or cancer initiating cells that have long term self-renewal potential and can fully recapitulate tumor phenotype at time of relapse. Inv(16) AML is a good example of this failure because inv(16) patients invariably show, at time of relapse, the inv(16) rearrangement, while other mutations detected at diagnosis (RAS, FLT3ITD, or KIT) may or may not be detected. Our hypothesis is that small molecule inhibitors of the binding of CBFβ-SMMHC to RUNX1 could be effective therapeutic drugs that eradicate the leukemia initiating cell population in inv(16) leukemia, thereby achieving better long term survival. Recently we developed a first generation inhibitor which targets the protein-protein interaction between CBFβ-SMMHC and RUNX1. In this application, we are proposing two aims: Aim 1: Optimization of CBFβ-SMMHC inhibitors for improved potency and ADMET properties. We propose to modify our first generation inhibitor to improve ADMET properties to develop a potent orally bioavailable inhibitor for the treatment of inv(16) leukemia. Specifically, we propose to modify the structure of the linker by substitution of five-membered heterocycle based linkers in the bivalent inhibitors we have developed to improve the solubility and the oral bioavailability of the inhibitor. The most promising compounds will be profiled for pharmacokinetic properties in mice and rats, as well as using a panel of in vitro ADMET properties. The most promising compounds will be tested in Aim 2 for in vivo efficacy and efficacy against inv(16) patient samples. Aim 2: Characterization of promising CBFβ-SMMHC inhibitors using AML patient cells and mouse models for inv(16) AML. We propose to determine the efficacy and specificity of the most promising inhibitors in reducing the survival of inv(16) AML compared to non-inv(16) AML patient samples in vitro. We also propose to determine their efficacy in mice, utilizing in vivo treatment in a genetically engineered model (GEM) and a patient-derived xenograft (PDX) mouse model for inv(16) acute myeloid leukemia. The inhibitors will be tested for their antileukemic activity in reducing engraftment, leukemia latency, and leukemia burden, as well as in eliminating the leukemia stem cells in recipient mice.