Microvesicle Dynamics in B-Cell Chronic Lymphocytic Leukemia Tumor Microenvironme

B 细胞慢性淋巴细胞白血病肿瘤微环境中的微泡动力学

• 批准号: 8574032
• 负责人: Asish Kumar Ghosh
• 金额: $ 32.4万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8574032
• 关键词: 11q23; 17p13; AKT Signaling Pathway; Address; B-Lymphocytes; Biochemical Genetics; Blood Circulation; Blood Platelets; Bone Marrow; CD19 gene; Cancer Patient; Cell Communication; Cell Proliferation; Cell Survival; Cell physiology; Cells; Chromosome Deletion; Chronic Lymphocytic Leukemia; Clinic; Clinical; Clinical Trials; Coculture Techniques; Code; Communication; Country; Cyclin D1; Data; Disease; Disease Progression; Environment; Evaluation; Functional RNA; Generations; Grant; Health; Human; In Vitro; Knowledge; Malignant Neoplasms; Mediating; Mediator of activation protein; Megakaryocytes; Messenger RNA; MicroRNAs; Monitor; Mutation; Nature; North America; Outcome; Pathogenesis; Patients; Phenotype; Phosphoric Monoester Hydrolases; Plasma; Play; Population; Prevention; Process; Production; Prognostic Factor; Proto-Oncogene Proteins c-akt; Reporting; Risk; Role; SRC gene; Sampling; Signal Pathway; Signal Transduction; Staging; Stimulus; Stromal Cells; System; Testing; Therapeutic; Time; Tissues; Transcript; Vascular Endothelial Growth Factors; Vesicle; autocrine; axl receptor tyrosine kinase; base; c-myc Genes; cancer cell; cell type; extracellular; follow-up; high risk; human ITGB3 protein; improved; in vivo; insight; leukemia; neoplastic cell; novel; paracrine; prevent; prognostic; public health relevance; response; therapy duration; tumor

DESCRIPTION (provided by applicant): Tumor cells influence their neighboring stroma to create a favorable niche for survival and advancement of the clinical course. To date, how the malignant cells alter the function of other cell types in surrounding tissues is largely unknown. Emerging evidence suggests that microvesicles (MV) produced by malignant cells are biologically active as a result of their ability to have both intimate and remote influences on hos stromal cells. Recently, we discovered circulating MV from B-Cell Chronic Lymphocytic Leukemia plasma are unique mediators of communication within the CLL microenvironment. We detected: (a) majority of CLL plasma contained elevated levels of MV; and (b) a phenotypic shift from predominantly "platelet-derived" (PD) MV (CD61+) in early stages of CLL toward a more "leukemic B-cell derived" (LD) MV (CD19+) during advanced stages. Most recently, we have detected that CLL B-cells can spontaneously or with stimulation produce LD MV in vitro irrespective of disease stages (Rai stage). In addition, we have shown that CLL MV and CLL stromal cell interaction results in robust activation of the AKT signaling pathway in CLL-bone marrow stromal cells (BMSC), leading to enhanced production of vascular endothelial growth factor (VEGF), a facilitator of leukemic B-cell survival, and sustained increases in cyclin D1 and c-myc, at least in part, by delivering Axl receptor tyrosine kinase (RTK). In contrast, increase in VEGF upon MV exposure also occurs with normal BMSC but at very subtle or diminished levels. Interestingly, we have detected intrinsic functional differences between normal and CLL BMSC that include: (i) CLL BMSC are hyper responsive to MV-mediated modulation of intracellular signaling; and (ii) express aberrantly activated signaling components, e.g., Axl and its downstream c-Src, involved in cell proliferation and survival. In addition, CLL BMSC express higher levels of the Src homology phosphatase-2 (SHP-2), reported to positively regulate the Src-signaling pathway. Based on our findings, the central hypothesis of this proposal is that MV generation in CLL is a dynamic process and that the circulating MV play a critical role in CLL pathogenesis as a result of MVs' unique ability to reprogram BMSC function with facilitation of CLL progression. Thus, neutralization of MV from circulation or inhibition of MV generation by the leukemic B-cells and/or prevention of MV interaction with the CLL stroma may halt disease progression and ultimately may apply to other human malignancies. Our hypothesis will be tested by addressing three specific aims: (1) Study the dynamics of MV generation in vitro by CLL B-cells; (2) Study the in vivo dynamics of MV generation and establish the relationship of CLL MV parameters to CLL progression and therapeutic outcome; (3) Interrogate the mechanism of aberrant function in CLL BMSC. We will study dynamics of in vitro generation of MV by purified CLL B-cells and whether CLL prognostic parameters or other in vitro stimulations are critical for the generation of LD-MV. We will study sequentially the dynamics of MV generation in CLL plasma and their relationship with prognostics and time to therapy. We will also study whether plasma MV levels and phenotype parameters predict therapeutic outcome in CLL patients being treated on two chemoimmunotherapy (CIT) clinical trials. Finally, using biochemical and genetic approach we will dissect mechanism of aberrant signaling in CLL BMSC and role of the Axl RTK in modulation of BMSC functions. Using these approaches we will be able to address our central hypothesis by acquiring more definitive knowledge of the dynamics of MV generation in CLL both in vitro and in vivo, ability of the circulating plasma MV to predict therapeutic outcome in CLL patients, nature of aberrant signaling in CLL BMSC and how the MV parameters associate with disease progression.

描述（由申请人提供）：肿瘤细胞影响其邻近的基质，为生存和临床进程的进展创造有利的生态位。到目前为止，恶性细胞如何改变周围组织中其他细胞类型的功能在很大程度上是未知的。新出现的证据表明，由恶性细胞产生的微泡（MV）具有生物活性，因为它们能够对宿主基质细胞产生亲密和远程影响。最近，我们发现来自B细胞慢性淋巴细胞白血病血浆的循环MV是CLL微环境中的独特通讯介质。我们检测到：（a）大多数CLL血浆含有升高水平的MV;和（B）从CLL早期阶段的主要“血小板衍生的”（PD）MV（CD 61+）向晚期阶段的更多“白血病B细胞衍生的”（LD）MV（CD 19+）的表型转变。最近，我们已经检测到CLL B细胞可以自发地或在刺激下在体外产生LD MV，而与疾病阶段（Rai阶段）无关。此外，我们已经表明，CLL MV和CLL基质细胞的相互作用导致在CLL-骨髓基质细胞（BMSC）中的AKT信号通路的稳健激活，导致血管内皮生长因子（VEGF）的产生增强，白血病B细胞存活的促进剂，以及细胞周期蛋白D1和c-myc的持续增加，至少部分地通过递送Axl受体酪氨酸激酶（RTK）。相比之下， MV暴露后的VEGF也发生在正常BMSC中，但水平非常轻微或降低。有趣的是，我们已经检测到正常和CLL BMSC之间的内在功能差异，包括：（i）CLL BMSC对MV介导的细胞内信号传导的调节反应过度;和（ii）表达异常激活的信号传导组分，例如，Axl及其下游c-Src参与细胞增殖和存活。此外，CLL BMSC表达更高水平的Src同源磷酸酶-2（SHP-2），据报道其正调节Src信号传导途径。基于我们的发现，该提议的中心假设是，CLL中的MV生成是一个动态过程，并且由于MV具有重新编程BMSC功能并促进CLL进展的独特能力，因此循环MV在CLL发病机制中起关键作用。因此，从循环中中和MV或抑制白血病B细胞产生MV和/或预防MV与CLL基质的相互作用可以阻止疾病进展，并最终可以应用于其他人类恶性肿瘤。 我们的假设将通过解决三个具体目标来检验：（1）研究CLL B细胞体外MV生成的动力学;（2）研究MV生成的体内动力学并建立CLL MV参数与CLL进展和治疗结果的关系;（3）询问CLL BMSC中异常功能的机制。我们将研究纯化的CLL B细胞体外产生MV的动力学，以及CLL预后参数或其他体外刺激是否对LD-MV的产生至关重要。我们将研究慢性淋巴细胞白血病血浆中MV生成的动力学及其与药物动力学和治疗时间的关系。我们还将研究血浆MV水平和表型参数是否预测两项化学免疫疗法（CIT）临床试验中治疗的CLL患者的治疗结果。最后，利用生物化学和遗传学方法，我们将剖析CLL BMSC中异常信号传导的机制以及Axl RTK在BMSC功能调节中的作用。使用这些方法，我们将能够解决我们的中心假设，通过获得更明确的知识MV生成在CLL在体外和体内的动力学，循环血浆MV预测治疗结果的能力在CLL患者，CLL BMSC异常信号的性质和MV参数如何与疾病进展。