Novel Substrate Competitive Bcr-Abl Inhibitor Active Against Gleevec-Resistant CM

描述（由申请人提供）：伊马替尼是一种BCR-ABL酪氨酸激酶抑制剂，用于治疗人类CML，取得了惊人的成功。然而，很大一部分长期接受伊马替尼治疗的患者由于BCR-ABL的激酶结构域获得突变而产生耐药性。我们最近开发了一种化合物（ON012380），它与BCR-ABL在不同于伊马替尼的位点结合，并在5-10 nM的浓度下诱导Ph+ CML细胞凋亡（比伊马替尼强10-50倍）。更有趣的是，这种化合物被发现在诱导到目前为止发现的所有抗伊马替尼的CML突变体死亡方面非常有效。在本应用中，我们建议对该化合物的作用机制和受该化合物影响的信号通路的性质进行详细的生化表征。目标是：1。确定ON012380对BCR-ABL的抑制动力学，并对BCR-ABL诱变克隆进行体外筛选，了解可能损害ON012380结合的氨基酸取代。2. 测定ON012380对(a)野生型和耐伊马替尼突变体BCR-ABL激酶活性的影响；(b)下游信号，如MAPK、AKT和STAT5的激活(c)细胞周期进程；(d)表达野生型或突变型BCR-ABL蛋白的肿瘤细胞中激活的凋亡通路的性质。3. 确定ON012380是否诱导Lyn过表达、伊马替尼耐药细胞死亡，如果诱导，确定作用机制。4. 4 .按照疗效研究的途径和方案进行药代动力学研究；对已建立的CML异种移植模型进行疗效试验。

DESCRIPTION (provided by applicant): Imatinib, which is an inhibitor of BCR-ABL tyrosine kinase and used for the treatment of human CML, has been a spectacular success. However, a significant proportion of patients chronically treated with imatinib develop resistance due to acquisition of mutations in the kinase domain of BCR-ABL. We have recently developed a compound (ON012380) that binds to BCR-ABL at a site different from imatinib and induces apoptosis of Ph+ CML cells at a concentration of 5-10 nM (which is 10-50 fold more potent than imatinib). More interestingly, this compound was found to be very effective in inducing the death of all of the imatinib-resistant mutants of CML identified so far. In this application, we propose to carry out a detailed biochemical characterization of the mechanism of action of this compound and the nature of signaling pathways that are affected by this compound. The aims are: 1. To determine the kinetics of inhibition of BCR-ABL by ON012380 and carry out in vitro screen of mutagenized BCR-ABL clones to gain an understanding of the amino acid substitutions that are likely to impair the binding of ON012380. 2. To determine the effects of ON012380 on (a) wild-type and imatinib-resistant mutants of BCR-ABL on the kinase activity; (b) downstream signaling such as MAPK, AKT and STAT5 activation (c) cell cycle progression; and (d) the nature of apoptotic pathways activated in tumor cells that express wild-type or mutant BCR-ABL protein. 3. Determine whether ON012380 induces cell death of Lyn overexpressing, imatinib resistant cells and if so, determine the mechanism of action. 4. Conduct pharmacokinetic studies by the route and schedule used for efficacy studies, and 5. Conduct efficacy trials in established xenograft models of CML.