Targeting Novel Pathways in JMML

项目概要/摘要 幼年型粒单核细胞白血病（JMML）是儿童期常见的骨髓增生性肿瘤（MPN）。 JMML的特征在于由于NF 1、CBL、KRAS、NRAS或PTPN 11中的突变而被Ras驱动，并且细胞 JMML患者对GM-CSF表现出超敏反应。化疗药物在JMML中大多无效， 唯一的治愈性治疗是异基因造血干细胞移植（HSCT）。一种常见的临床 JMML的图片是，它表现为一种高度炎症综合征，通常很难区分， 病毒感染因此，JMML的一种成分与高炎症状态和先天性高活动性相关。 免疫细胞此外，与其他MPN不同，JMML很少进展到爆炸危机;相反，死亡率是由于 髓外骨髓细胞扩增导致器官衰竭。重要的是，在同种异体HSCT后， 患者死于白血病复发，暗示骨髓微环境（BME）在JMML中的作用 发展和进步。JMML的高度炎症性质可能会损害BME，改变BME的功能。 移植后正常供体细胞的扩增，允许残留的白血病细胞竞争超过正常供体细胞。 移植，并导致复发。利用JMML小鼠模型，我们证明了携带PTPN 11的小鼠的复发 突变，我们显示PTPN 11荷瘤小鼠BME的组成发生了改变，并提供了JMML 在HSCT时具有较高中性粒细胞计数的患者更可能复发。这些数据结合 先前的研究表明，PTPN 11突变导致中性粒细胞过度活跃和炎症， 这些细胞可能会导致复发我们将详细研究这一点。我们一直在分析多种RNA 在JMML中差异表达的lncRNA的测序数据集。在此过程中，我们发现了几个 其表达受到差异调节的新型lncRNA。我们将研究这些lncRNA如何 有助于JMML发病机制。我们最近发现，PI 3 K催化亚基p110δ有助于 Akt和Erk超活化，并促进PTPN 11诱导的GM-CSF超敏反应， 过度增殖，从而部分促进JMML的进展。由于缺乏完整的救援， 在PTPN 11诱导的JMML中p110δ的缺失，我们寻找与p110δ一起信号传导的假定酪氨酸激酶 在PI 3 K-Akt信号通路中，必须靶向最佳JMML治疗。我们提供初步数据 证明布鲁顿酪氨酸激酶（BTK）抑制与PI 3 K p110δ抑制协同作用， PTPN 11表达细胞中Akt和Erk的激活。我们将研究这种合作背后的机制。 总体而言，提出的目标将揭示新的见解JMML的发展和发病机制，以及 新的治疗靶点的鉴定。

PROJECT SUMMARY/ABSTRACT Juvenile myelomonocytic leukemia (JMML) is a common myeloproliferative neoplasm (MPN) in childhood. JMML is characterized as being Ras-driven due to mutations in NF1, CBL, KRAS, NRAS, or PTPN11, and cells from JMML patients show hypersensitivity to GM-CSF. Chemotherapeutic agents are mostly ineffective in JMML, and the only curative treatment is allogeneic hematopoietic stem cell transplantation (HSCT). A common clinical picture in JMML is that it presents as a hyperinflammatory syndrome, and is often difficult to distinguish from viral infections. Thus, a component of JMML is associated with hyperinflammatory state and hyperactive innate immune cells. Further, unlike other MPNs, JMML rarely progresses to blast crisis; rather, mortality is due to extramedullary myeloid cell expansion leading to organ failure. Importantly, following allogeneic HSCT, 50% of patients succumb to leukemia relapse, implicating a role for bone marrow microenvironment (BME) in JMML development and progression. The hyperinflammatory nature of JMML may damage the BME, altering the expansion of normal donor cells following transplant, permitting residual leukemia cells to outcompete the normal graft, and leading to relapse. Utilizing mouse models of JMML, we demonstrate relapse in mice bearing PTPN11 mutations, we show altered composition of the BME in PTPN11 bearing mice and provide evidence that JMML patients that have a higher neutrophil count at the time of HSCT are more likely to relapse. These data combined with previous studies demonstrating hyperactive and inflamed neutrophils due to PTPN11 mutations suggests that these cells may contribute to relapse. We will examine this in detail. We have been analyzing multiple RNA sequencing datasets for lncRNAs that are differentially expressed in JMML. In doing so, we identified several novel lncRNAs whose expression is differentially regulated. We will examine how one of these lncRNAs contributes to JMML pathogenesis. We have recently shown that PI3K catalytic subunit p110δ contributes to both Akt and Erk hyperactivation, and promotes PTPN11-induced GM-CSF hypersensitivity and hyperproliferation, thus partially contributing to the progression of JMML. Given the lack of complete rescue by loss of p110δ in PTPN11-induced JMML, we sought out putative tyrosine kinases that signal together with p110δ in the PI3K-Akt signaling pathway that must be targeted for optimal JMML therapy. We present preliminary data demonstrating that Bruton's Tyrosine Kinase (BTK) inhibition collaborates with PI3K p110δ inhibition to reduce the activation of Akt and Erk in PTPN11-expressing cells. We will study the mechanism behind this cooperation. Overall, the proposed Aims will shed novel insight into JMML development and pathogenesis as well as identification of novel therapeutic targets.