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

项目摘要/摘要 经典的骨髓增生性肿瘤(MPN)是一种血液疾病，在美国约有30万人受到影响 美国血液凝结并发症和骨髓衰竭可能导致死亡， 无法治愈的白血病。通过干细胞移植进行根治性治疗几乎是不可能的。异常调节的一种 名为JAK2的蛋白质驱动这些疾病，虽然JAK2抑制剂改善了MPN患者的症状，但它们确实 不能诱导缓解，固有耐药性是一个主要的临床瓶颈。我们最近的研究 提示一种名为SHP2的蛋白质在MPN细胞对FDA批准的JAK的反应中发挥着独特的作用 抑制剂鲁索利替尼。随着药物的最新发展，靶向SHP2的治疗现在成为可能 这起到了分子粘合剂的作用，使SHP2保持在不活跃的状态。MPN细胞在体内的早期存活 鲁索利替尼治疗面临的是一种被称为持久性的耐药性。我们目前的研究表明 Ruxolitinib持久性细胞对SHP2抑制比从未接触过SHP2的细胞更敏感 鲁索利替尼。在后一种细胞中，ruxolitinib抑制JAK2依赖的信号，包括STAT和ERK蛋白。 然而，即使鲁索利替尼仍然存在，ERK也会迅速重新激活。我们观察到， Shp2抑制可阻断ERK的这种重新激活。由于ERK可以促进细胞生长/存活，因此有可能 这改变了鲁索利替尼治疗期间SHP2的调节，导致细胞存活。有趣的是，激活 在宿存细胞中，介导JAK2信号转导的蛋白质状态对SHP2抑制的反应不同。 提示Ruxolitinib持续期间的细胞信号处于重新连接状态。这也许可以解释我们的 观察到抑制SHP2可以防止Ruxolitinib持续状态。因此，SHP2可以提供一个 可被利用来改进MPN治疗的脆弱性，我们的观察进一步支持了这一点 结论：抑制SHP2能拮抗MPN小鼠模型的疾病，并能提高其抑制作用。 鲁索利替尼对MPN患者细胞的影响。此应用程序的主要目标是确定 SHP2抑制克服了目前抗JAK2 MPN治疗的障碍。中心假设是 靶向SHP2将阻止JAK2抑制剂持久性的发展，这在MPN患者中观察到。 我们将利用细胞、遗传学和生物学方法，包括小鼠模型和MPN细胞 我们研究中的患者。目标1中的实验将确定SHP2抑制的机制细节 使MPN细胞对JAK2抑制敏感；在AIM 2中将评估SHP2在药物持久性中的作用；在AIM中 3将确定响应ruxolitinib的SHP2信号改变的分子基础/后果， 有可能根据我们的新观察结果开发新的治疗方法。我们的研究是 创新是因为SHP2在JAK2抑制剂治疗中的独特作用是完全未知的 在这些MPN中使用SHP2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.