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

伊马替尼是一种BCR-ABL酪氨酸激酶的抑制剂，用于治疗人类CML， 已经取得了惊人的成功。然而，相当大比例的长期接受治疗的患者 伊马替尼产生耐药性是因为获得了bcr-abl激活域的突变。我们有 最近开发了一种化合物(ON012380)，它与bcr-abl结合的位点不同于伊马替尼和 在5-10 nM浓度下诱导Ph+CML细胞凋亡(其效力是 伊马替尼)。更有趣的是，这种化合物被发现对所有人的死亡都非常有效 到目前为止已发现的慢性粒细胞白血病对伊马替尼耐药突变株。在此应用程序中，我们建议执行 该化合物的作用机制和性质的详细生化表征 受这种化合物影响的信号通路。其目的是：1.确定其动力学 ON012380对bcr-abl的抑制作用及其诱变克隆的体外筛选 了解可能模仿ON012380结合的氨基酸取代。 2.检测ON012380对(A)野生型和伊马替尼耐药突变株bcr-abl的作用。 (B)下游信号，如MAPK、AKT和STATS激活(C)细胞 周期进程；和(D)在表达野生型的肿瘤细胞中激活的凋亡通路的性质 或突变的bcr-abl蛋白。3.确定ON012380是否诱导Lynover表达的细胞死亡， 伊马替尼耐药细胞，如果是的话，确定其作用机制。4.进行药代动力学研究 通过用于疗效研究的路线和时间表，以及5.在已建立的异种移植中进行疗效试验 慢性粒细胞白血病的模型。

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 mutagenizedBCR-ABL clones to gain an understanding of the amino acid substitutions that are likely to imapir 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 STATS 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 Lynoverexpressing, imatinib resistant cells and if so, determinethe mechanismof 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.