Targeting cancer stem cells in JAK2V617F induced neoplasm

项目摘要/摘要 我们的目标是为JAK2V617F诱导的一种主要形式的疾病开发一种新的治疗策略 骨髓增生性肿瘤(MPN)，真性红细胞增多症(PV)，重点针对PV启动细胞 (PV中的癌症干细胞)。目前仍缺乏针对PV的根治疗法。建议的研究是基于我们的 花生四烯酸5-脂氧合酶(5-LO)基因(ALOX5)在生存中的关键作用 光伏启动细胞的调控。Alox5途径是已知的产生炎症(引起哮喘)的途径 白三烯，以及FDA批准的人类抗哮喘药物Singulair(Montelukast)BLOCKS 白三烯受体结合可降低炎症反应。我们已经发现，Singulair抑制了 表达JAK2-V617F的细胞在体外和小鼠体内的生长因此，Singulair可能是一种有效的新制剂。 用于治疗PV。我们假设在ALOX5途径中产生的白三烯在 在PV中MPN启动细胞的存活调节中的作用，而Singulair拮抗 白三烯作为一种潜在的治疗PV的新药物。检验这一假说是有临床意义的 意义和益处：1)未进展为急性髓系白血病(AML)的PV患者； 2)AML临床缓解期残留JAK2V617F表达细胞的PV患者 随着时间的推移复发；3)骨髓移植治疗AML的PV患者进展为 PV但仍有残留的JAK2V617F表达细胞；4)可检测到 JAK2V617F在髓系细胞中转录，但没有出现PV的临床症状。因为Alox5 已知的途径是产生白三烯，一个看似合理的机制解释Singulair的作用是 它通过阻断白三烯与PV启动细胞的受体结合来根除PV。我们还需要知道 Singulair抑制光伏启动细胞和光伏发展的潜在分子机制。在……里面 事实上，我们的初步研究表明，JAK2V617F调节涉及两个Alox5的Alox5途径 下游基因，β-连环蛋白(作为刺激因子)和Blk(作为抑制因子)，这将是重要的 研究Singuliar是否调节PV启动细胞中的这两个基因。最后，至关重要的是 确定Singulair是否抑制人类PV启动细胞的生长。具体目标是：1) 确定PV启动细胞的存活是否依赖于白三烯，以及是否阻断 用Singulair减少白三烯对PV启动细胞的影响；2)确定分子 Singulair抑制光伏启动细胞和光伏发展的机制；以及3)确定 Singulair是否阻断人PV启动细胞的ALOX5通路并减少人的植入 免疫缺陷小鼠中的PV启动细胞。广泛地说，Singulair是一种潜在的固体治疗剂 Alox5等肿瘤与结肠、肺、胰腺、肝脏、食道、皮肤等的肿瘤发生有关。

Project Summary/Abstract We aim to develop a new therapeutic strategy for one major form of JAK2V617F-induced myeloproliferative neoplasms (MPNs), polycythemia vera (PV), with a focus on targeting PV-initiating cells (cancer stem cells in PV). A curative therapy for PV is still lacking. The proposed studies are based on our preliminary finding that the arachidonate 5-lipoxygenase (5-LO) gene (Alox5) plays a key role in survival regulation of PV-initiating cells. The Alox5 pathway is known for producing inflammatory (asthma-causing) leukotrienes, and an FDA-approved human anti-asthma drug called Singulair (Montelukast) blocks leukotriene receptor binding to reduce the inflammatory response. We have found that Singulair inhibits the growth of JAK2-V617F-expressing cells in vitro and in mice. Thus, Singulair could be an effective new agent for treating PV. We hypothesize that leukotrienes produced in the Alox5-pathway play an essential role in survival regulation of MPN-initiating cells in PV, and Singulair antagonizes the action of leukotrienes to act as a potential new therapeutic agent for PV. Testing this hypothesis is of clinical significance and would benefit: 1) PV patients who have not progressed to acute myeloid leukemia (AML); 2) PV patients who are in clinical remission of AML with residual JAK2V617F-expressing cells and may relapse with time; 3) PV patients who had bone marrow transplantation for treating AML progressed from PV but still have residual JAK2V617F-expressing cells; and 4) the individuals who have detectable JAK2V617F transcripts in myeloid cells but have not developed clinical symptoms of PV. Because the Alox5 pathway is known to produce leukotrienes, one plausible mechanistic explanation of action of Singulair is that it eradicates PV by blocking receptor binding of leukotriens to PV-initiating cells. We also need to know the underlying molecular mechanisms by which Singulair inhibits PV-initiating cells and PV development. In fact, our preliminary studies show that JAK2V617F regulates the Alox5 pathway involving two Alox5 downstream genes, beta-catenin (as a stimulator) and Blk (as a suppressor), and it will be important to investigate whether Singuliar regulates these two genes in PV-initiating cells. Finally, it is critical to determine whether Singulair inhibits the growth of human PV-initiating cells. The specific aims are: 1) To determine whether the survival of PV-initiating cells is dependent on leukotrienes and whether a blockade of leukotrienes by Singulair reduces their effects on PV-initiating cells; 2) To determine the molecular mechanisms by which Singulair inhibits PV-initiating cells and PV development; and 3) To determine whether Singulair blocks the Alox5 pathway in human PV-initiating cells and reduces engraftment of human PV-initiating cells in immunocompromised mice. Broadly, Singulair is a potential therapeutic agent for solid tumors as Alox5 is associated with tumorigenesis in the colon, lung, pancreas, liver, esophagus, skin, etc.