Identification of New Targets and Novel Treatment Strategies for Chronic Mye

项目总结(见说明)： 认识慢性粒细胞白血病的新靶点和新治疗策略。拉尔夫·B。 阿里纳豪斯。博士-我的实验室发布了关于慢性前列腺癌的几个关键蛋白质的新信息 受bcr-abl癌蛋白调控的髓性白血病。这些蛋白质是Lipocalin 2 (NGAL/24p3)、JAK2和BCR。我们首次发现Lipocalin 2在bcr-Abl诱导的白血病(LINE)中的作用 等人的研究。致癌基因2005)。我们最近对24p3缺失小鼠的研究表明，bcr-Abl+细胞分泌24p3 是bcr-Abl在小鼠模型中诱导白血病所必需的(Leng等人)。癌基因2008)。 关于JAK2，我们表明它是一个大型信号网络的一部分(Samanta等人，CAN Res.，2006)。 JAK2的抑制作用诱导对伊马替尼敏感/耐药的bcr-Abl+细胞、CML细胞系和 急变期CML患者的细胞。关于bcr，野生型bcr蛋白抑制bcr的致癌功能 但丝氨酸/苏氨酸激酶缺陷的bcr增强bcr-abl(Perazzona Et)的致癌作用 阿尔..。致癌基因，2008)。目的#1，研制能阻断Lipocalin 2(NGAL/24p3)活性的单抗 Bcr-Abl诱导，并观察其对小鼠白血病模型的影响。我们的目标是干扰 NGAL联合格列卫等其他治疗方案治疗慢性粒细胞白血病 心理治疗。目的#2，研究新型JAK2抑制剂对伊马替尼敏感和耐药的机制 CML细胞系、患者细胞和晚期CML患者细胞的长期目标是 对耐伊马非尼的慢性粒细胞白血病和晚期慢性粒细胞白血病进行临床试验(与Cortes博士合作)。我们假设一个 有效的JAK2抑制剂将用于治疗耐药的CML以及CML的所有阶段 这是因为JAK2在CML细胞的致癌信号中起主导作用。我们发现了一种新的JAK2 干扰BCR-Abl/JAK2/HSP90信号网络复合体导致细胞凋亡的抑制剂(WP1193) 耐药CML细胞和急变CML细胞。令人惊讶的是，初步结果表明JAK2 激酶使bcr-Abl的Tyr177磷酸化，在JAK2抑制纤维蛋白后，大大减少了Grb2与 网络复杂，并导致RAS和PI-3信号通路的中断。重要的是 JAK2抑制也显著降低bcr-abl蛋白水平，导致STAT5和STAT3下调 发信号。因此，JAK2的抑制作用破坏了CML的许多致癌效应，如果不是全部的话。目标#3，塑造 Bcr-Ser/Thr激酶在调节bcr-Abl致癌活性中的作用我们将在基因中寻找突变 BCR激酶结构域，因为我们假设这种突变在CML疾病进展中发挥作用。

PROJECT SUMMARY (See instructions): Idenfificafion of new targets and novel treatment strategies for chronic mvelold leukemia. Ralph B. Arilnahaus. Ph.D.- My laboratory has published new information on several key proteins in chronic myelogenous leukemia that are regulated by the Bcr-Abl oncoprotein. These proteins are lipocalin 2 (NGAL/24p3), Jak2 and Bcr. We were first to discover the role of lipocalin 2 in Bcr-Abl induced leukemia (Lin et al. Oncogene 2005). Our recent studies with 24p3 null mice showed that 24p3 secretion by Bcr-Abl+ cells is a requirement for leukemia inducfion by Bcr-Abl in a mouse model (Leng et al.. Oncogene 2008). Regarding Jak2, we show that it is part of a large signaling network (Samanta et al., Can Res., 2006). Inhibifion of Jak2 induces apoptosis in imatinib-sensitive/resistant Bcr-Abl + cells, in CML cell lines and in cells from blast crisis CML patients. Concerning Bcr, wild-type Bcr protein inhibits the oncogenic function of Bcr-Abl but serine/threonine kinase-defective Bcr enhances the oncogenic effects of Bcr-Abl (Perazzona et al.. Oncogene, 2008). Aim #1, Develop a monoclonal anfibody that blocks lipocalin 2 (NGAL/24p3) activities induced by Bcr-Abl, and investigate the effects in mouse leukemia models. Our goal is to interfere with NGAL function for treatment of CML in combination with other therapeutic regimens such as Gleevec therapy. Aim #2, Investigate the mechanistic effects of new Jak2 inhibitors in imatinib-sensitive and resistant CML cell lines, patient cells, and in patient cells from advanced stages of CML with the long-term goal of doing clinical trials in imafinib-resistant CML and late stage CML (with Dr. Cortes). We hypothesize that a potent Jak2 inhibitor will be useful in the treatment of drug-resistant CML as well as in all stages of CML because of the dominant role of Jak2 in oncogenic signaling in CML cells. We have identified a new Jak2 inhibitor (WP1193) that disrupts the Bcr-Abl/Jak2/HSP90 signaling network complex leading to apoptosis of drug-resistant CML cells and blast crisis CML cells. Surprisingly, preliminary results indicate that the Jak2 kinase phosphorylates Tyr 177 of Bcr-Abl, which upon Jak2 inhibifion drasfically reduced Grb2 binding to the network complex and caused the disruption of the Ras and PI-3 kinase signaling pathways. Importantly, Jak2 inhibition also drastically reduced Bcr-Abl protein levels, causing down-regulafion of STAT5 and STAT3 signaling. Thus, Jak2 inhibition disrupts many If not all oncogenic effects in CML. Aim #3, Invesfigate the role ofthe Bcr Ser/Thr kinase in regulafing Bcr-Abl oncogenic activity. We will search for mutations in the Bcr kinase domain, as we hypothesize that such mutations play a role in CML disease progression.