Strategies to target BCR-ABL1 compound mutants in CML and Ph+ ALL

CML 和 Ph ALL 中针对 BCR-ABL1 复合突变体的策略

• 批准号: 10579462
• 负责人: Michael W. Deininger
• 金额: $ 36.99万
• 依托单位: VERSITI WISCONSIN, INC.
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-11-10 至 2025-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10579462
• 关键词: ABL1 gene; Acute Myelocytic Leukemia; Address; Affinity; Alleles; Allosteric Site; American; Binding; Binding Sites; Biochemical; Biophysics; Blast Phase; Bypass; Cessation of life; Chronic Myeloid Leukemia; Chronic-Phase Myeloid Leukemia; Clinical; Clinical Trials; Communication; Complex; Crystallography; Dasatinib; Dependence; Distant; Dose; Enzyme Inhibition; Event; Exhibits; FDA approved; Foundations; Gatekeeping; Imatinib; Knowledge; Laboratory Study; Leukemic Cell; Malignant Neoplasms; Malignant neoplasm of lung; Medical; Medicine; Methods; Molecular Conformation; Mutation; Non-Small-Cell Lung Carcinoma; Patient-Focused Outcomes; Patients; Ph+ ALL; Pharmaceutical Preparations; Philadelphia Chromosome; Philadelphia Chromosome Positive Chronic Myelogenous Leukemia; Phosphotransferases; Physiological; Prevalence; Probability; Protac; Proto-Oncogene Proteins c-abl; Protocols documentation; Rationalization; Recurrent disease; Refractory; Regulatory Element; Reporting; Residual state; Resistance; Sampling; Signal Transduction; Site; Site-Directed Mutagenesis; System; Technology; Testing; Therapeutic; Treatment Failure; Tyrosine Kinase Inhibitor; Work; Xenograft procedure; clinical development; effective therapy; improved; inhibitor; leukemia; melanoma; mouse model; mutant; novel therapeutic intervention; optimal treatments; research clinical testing; resistance mechanism; resistance mutation; targeted treatment

Abstract: Philadelphia chromosome-positive (Ph+) leukemia is caused by BCR-ABL1, a constitutively active fusion kinase. Tyrosine kinase inhibitors (TKIs) targeting the ATP site of BCR-ABL1 are effective in treating chronic-phase chronic myeloid leukemia (CP-CML) yet minimally effective at treating blast-phase CML and Ph+ acute lymphoblastic leukemia. In the 20 years since the approval of the first TKI in all of medicine, imatinib, TKIs have dramatically improved survival of patients with CP-CML, resulting in a projected increase of CML prevalence from 70,000 Americans in 2010 to 180,000 in 2050. Despite this progress, TKI-resistant CML remains a challenge, with >1,000 deaths annually in the U.S. At least 50% of TKI treatment failure arises through mutations in BCR-ABL1. Laboratory studies on the five FDA-approved BCR-ABL1 TKIs have established their mutational profiles against the >30 mutations observed in patients. In aggregate, these TKIs cover the clinical spectrum of BCR-ABL1 single point mutants. Ponatinib is the only TKI that is clinically effective against the T315I gatekeeper mutant. However, BCR-ABL1 compound mutants, defined as 2 mutations in the same BCR-ABL1 allele, that include T315I with any second mutation are resistant to all approved TKIs, including ponatinib, leaving these patients with no further treatment options. Asciminib is the first inhibitor in clinical development that binds the BCR-ABL1 myristoyl site, an allosteric site distant from the ATP site, to enforce an autoinhibited, inactive conformation. We established that asciminib, like ponatinib, is not effective against T315I-inclusive compound mutants, yet combining ponatinib (but not nilotinib or dasatinib) with asciminib is extremely effective at inhibiting many T315I-inclusive compound mutant forms of BCR-ABL1. This discovery provides the basis for a novel therapeutic strategy to address an entirely unmet medical need and is the foundation of this proposal. In Aim 1, we will use computational, biophysical and crystallographic methods to decipher how ponatinib re-sensitizes compound mutant BCR-ABL1 to asciminib. We will test the combination in relevant mouse models and in primary leukemia samples. In Aim 2A, we will develop a therapeutic strategy for clinically resistant BCR-ABL1 compound mutants that are not inhibited by the combination of ponatinib with asciminib. Instead, we will target these mutants for proteasomal degradation using an asciminib proteolysis targeting chimera (PROTAC) strategy. Unlike TKIs, PROTACs are effective even upon transient or weak binding. We will test the hypothesis that ponatinib-induced stabilization of the myristoyl site is the initiating event that allows subsequent binding of an asciminib-PROTAC and proteasomal degradation of compound mutant BCR-ABL1. In Aim 2B, we will develop a ponatinib-PROTAC strategy for compound mutants carrying a myristoyl site resistance mutation. Our work will provide a rationale for clinical evaluation of ponatinib combined with asciminib as a therapy for currently untreatable BCR-ABL1 compound mutant leukemia. Compound mutations are also a major cause of resistance in acute myeloid leukemia, melanoma, and lung cancer, and our study will provide a blueprint for treating these malignancies.

摘要：费城染色体阳性（pH+）白血病是由组成型活性的BCR-ABL1引起的 融合激酶。靶向BCR-ABL1 ATP位点的酪氨酸激酶抑制剂（TKI）有效治疗 慢性期慢性髓样白血病（CP-CML），但在治疗爆炸相CML和pH+方面有效 急性淋巴细胞白血病。自所有医学中的第一个TKI批准以来的20年，伊马替尼，TKIS CP-CML患者的存活率大大提高，导致CML预计增加 从2010年的70,000名美国人的患病率到2050年的180,000。 一个挑战，美国每年至少有1,000人死亡，至少有50％的TKI治疗失败是通过 BCR-ABL1中的突变。关于五个FDA批准的BCR-ABL1 TKI的实验室研究已经建立了他们的 反对患者观察到的> 30个突变的突变谱。总体上，这些TKI覆盖了临床 BCR-ABL1单点突变体的频谱。 Ponatinib是唯一针对T315i具有临床有效的TKI 网守突变体。但是，在同一BCR-ABL1中定义为2突变的BCR-ABL1化合物突变体 等位基因，包括任何第二突变的T315i，对包括Ponatinib在内的所有批准的TKI都具有抗性 这些没有进一步治疗选择的患者。 Asciminib是临床发育中的第一个抑制剂 BCR-ABL1 Myristoyl站点是一个远离ATP站点的变构位点，以实施自身抑制，不活跃 构象。我们确定，阿西米尼（Asciminib）像庞蒂尼（Ponatinib 突变体，却将ponatinib（但不是尼洛替尼或达沙替尼）与assiminib结合在一起，在抑制中非常有效 BCR-ABL1的许多T315i包含复合突变体形式。这一发现为小说提供了基础 治疗策略以满足完全未满足的医疗需求，这是该提议的基础。在AIM 1中， 我们将使用计算，生物物理和晶体学方法来解密Ponatinib如何重新敏感 复合突变体BCR-ABL1至asciminib。我们将在相关的鼠标模型和主要的鼠标模型中测试组合 白血病样品。在AIM 2A中，我们将制定一种用于临床抵抗BCR-ABL1复合材料的治疗策略 不受ponatinib与阿西米尼的结合抑制的突变体。相反，我们将针对这些突变体 用于使用Asciminib蛋白水解靶向嵌合体（Protac）策略的蛋白酶体降解。与tkis不同， 即使在短暂或弱结合下，Protac也有效。我们将测试ponatinib诱导的假设 Myristoyl位点的稳定是允许随后结合Asciminib-Protac的开始事件 和复合突变体BCR-ABL1的蛋白酶体降解。在AIM 2B中，我们将开发Ponatinib-Protac 携带肉豆蔻酰基耐药性突变的复合突变体的策略。我们的工作将提供理由 为了临床评估Ponatinib与Asciminib合并为目前不可治疗的BCR-ABL1的疗法 复合突变体白血病。复合突变也是急性髓样抗性的主要原因 白血病，黑色素瘤和肺癌，我们的研究将为治疗这些恶性肿瘤提供蓝图。