Targeting altered phosphatase-dependent signaling to overcome the inefficacy of targeted therapy in myeloproliferative neoplasms

项目总结/摘要 经典骨髓增生性肿瘤（MPN）是血液疾病，影响约300，000人， 美国凝血并发症和骨髓衰竭可导致死亡， 无法治愈的白血病通过干细胞移植的治愈性治疗很少是可能的。a的异常调节 一种叫做JAK 2的蛋白质驱动这些疾病，虽然JAK 2抑制剂可以改善MPN患者的症状， 不能诱导缓解，固有的耐药性是主要的临床瓶颈。我们最近的研究 这表明一种名为SHP 2的蛋白质在MPN细胞对FDA批准的JAK的反应中起着独特的作用 抑制剂ruxolitinib。随着最近药物的发展，治疗靶向SHP 2现在是可能的 其功能就像分子胶水一样，使SHP 2保持在非活性状态。MPN细胞的前期存活率在 ruxolitinib治疗的表面是一种称为持久性的耐药性形式。我们目前的研究表明， 鲁索利替尼持久性细胞比从未暴露于SHP 2的细胞对SHP 2抑制更敏感。 鲁索利替尼。在后者细胞中，ruxolitinib抑制JAK 2依赖性信号，包括STAT和ERK蛋白。 然而，即使ruxolitinib仍然存在，ERK也会迅速重新激活。我们观察到 SHP 2抑制阻断ERK的这种再激活。由于ERK可以促进细胞生长/存活， 在ruxolitinib治疗期间改变的SHP 2调节导致细胞存活。有趣的是， 介导JAK 2信号传导的蛋白质状态对持久细胞中的SHP 2抑制反应不同， 这表明在鲁索利替尼持续期间细胞信号传导处于重新连接状态。这也许可以解释我们的 观察到SHP 2抑制可以防止鲁索利替尼持续状态。因此，SHP 2可以提供 我们的观察结果进一步支持了这一点， SHP 2抑制可以拮抗MPN小鼠模型中的疾病，并且可以改善 鲁索替尼对来自MPN患者的细胞的作用。本申请的主要目的是确定 该SHP 2抑制克服了目前抗JAK 2 MPN治疗的障碍。核心假设是， 靶向SHP 2将阻碍JAK 2抑制剂持续性的发展，这在MPN患者中观察到。 我们将利用细胞，遗传和生物学方法，包括小鼠模型和来自MPN的细胞 患者在我们的研究。目的1中的实验将确定SHP 2抑制的机制细节。 使MPN细胞对JAK 2抑制敏感;在目的2中将评估SHP 2在药物持久性中的作用;并且在目的3中将评估SHP 2在药物持久性中的作用。 3将确定响应鲁索利替尼的改变的SHP 2信号传导的分子基础/后果， 有可能帮助开发新的治疗方法，基于我们的新观察。我们的研究是 创新，因为SHP 2在响应JAK 2抑制剂治疗中的独特作用完全未知 并且在这些MPN中利用SHP 2作为治疗靶点从未被测试过。我们的研究可以帮助 为美国30万患有MPN的人开发有效的治疗方法。

Project Summary/Abstract Classical myeloproliferative neoplasms (MPNs) are blood disorders that affect about 300,000 people in the U.S. Blood clotting complications and bone marrow failure can cause death, as can the development of an incurable leukemia. Curative therapy by stem cell transplant is rarely possible. Aberrant regulation of a protein called JAK2 drives these disorders, and while JAK2 inhibitors improve MPN patient symptoms they do not induce remission, with inherent drug resistance being a major clinical bottleneck. Our recent studies suggest a protein called SHP2 plays a unique role in the response of MPN cells to the FDA-approved JAK inhibitor ruxolitinib. Therapeutically targeting SHP2 is now possible following the recent development of drugs that function as molecular glue to keep SHP2 stuck in an inactive state. The upfront survival of MPN cells in the face of ruxolitinib treatment is a form of drug resistance called persistence. Our current studies show that ruxolitinib persistent cells are more sensitive to SHP2 inhibition than cells that have never been exposed to ruxolitinib. In the latter cells ruxolitinib inhibits JAK2-dependent signals including STAT and ERK proteins. However, ERK rapidly becomes re-activated even while ruxolitinib is still present. We have observed that SHP2 inhibition blocks this re-activation of ERK. Since ERK can promote cell growth/survival, it is possible that altered SHP2 regulation during ruxolitinib treatment leads to cell survival. Interestingly, the activation states of proteins that mediate JAK2 signaling respond differently to SHP2 inhibition in persistent cells, suggesting cell signaling during ruxolitinib persistence is in a re-wired state. This may explain our observations that SHP2 inhibition can prevent a ruxolitinib persistent state. Thus, SHP2 may provide a vulnerability that can be exploited to improve MPN therapy, which is further supported by our observations that SHP2 inhibition can antagonize disease in an MPN mouse model and can improve the inhibitory effect of ruxolitinib on cells from MPN patients. The major objective of this application is to determine the extent to which SHP2 inhibition overcomes barriers of current anti-JAK2 MPN therapy. The central hypothesis is that targeting SHP2 will thwart the development of JAK2 inhibitor persistence, which is observed in MPN patients. We will utilize cellular, genetic, and biological approaches, including mouse models and cells from MPN patients in our studies. Experiments in aim 1 will determine mechanistic details by which SHP2 inhibition sensitizes MPN cells to JAK2 inhibition; in aim 2 will assess the role of SHP2 in drug persistence; and in aim 3 will determine the molecular basis/consequences of altered SHP2 signaling in response to ruxolitinib, which has potential to help develop new therapeutic approaches based on our novel observations. Our studies are innovative because the unique role of SHP2 in response to JAK2 inhibitor treatment is completely unknown and utilizing SHP2 as a therapeutic target in these MPNs has never been tested. Our studies could contribute to the development of effective therapies for the 300,000 people in the U.S. who suffer with an MPN.