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: 8703043
• 负责人: Asish Kumar Ghosh
• 金额: $ 31.43万
• 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/8703043
• 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基质，为临床病程的生存和进展创造有利的生态位。迄今为止，恶性细胞如何改变周围组织中其他细胞类型的功能尚不清楚。新的证据表明，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密切和远程影响。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 微环境中独特的通讯介质。我们检测到：(a) 大多数 CLL 血浆中 MV 水平升高； (b) 表型从 CLL 早期阶段主要的“血小板衍生”(PD) MV (CD61+) 转向晚期阶段更多的“白血病 B 细胞衍生”(LD) MV (CD19+)。最近，我们发现 CLL B 细胞可以自发地或在刺激下在体外产生 LD MV，无论疾病阶段（Rai 阶段）如何。此外，我们还发现，CLL MV 和 CLL 基质细胞相互作用会导致 CLL 骨髓基质细胞 (BMSC) 中 AKT 信号通路的强烈激活，从而导致血管内皮生长因子 (VEGF) 的产生增强，血管内皮生长因子 (VEGF) 是细胞因子的促进剂。白血病 B 细胞存活，以及细胞周期蛋白 D1 和 c-myc 的持续增加（至少部分是通过传递 Axl 受体酪氨酸激酶） （RTK）。相比之下，增加 MV 暴露后，正常 BMSC 也会出现 VEGF，但水平非常微妙或降低。有趣的是，我们发现正常和 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调节高度敏感； (ii) 表达异常激活的信号成分，例如 Axl 及其下游 c-Src，参与细胞增殖和存活。此外，CLL BMSC 表达较高水平的 Src 同源磷酸酶-2 (SHP-2)，据报道可积极调节 Src 信号通路。根据我们的研究结果，该提议的中心假设是，CLL 中 MV 的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 发病机制中发挥着关键作用。因此，中和循环中的 MV 或抑制白血病 B 细胞产生 MV 和/或防止 MV 与 CLL 基质相互作用可能会阻止疾病进展，并最终可能适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进行检验：（1）研究 CLL B 细胞在体外产生 MV 的动态； (2) 研究MV产生的体内动态并建立CLL MV参数与CLL进展和治疗结果的关系； (3)探讨CLL BMSC功能异常的机制。我们将研究纯化的 CLL B 细胞在体外产生 MV 的动态，以及 CLL 预后参数或其他体外刺激对于 LD-MV 的产生是否至关重要。我们将依次研究 CLL 血浆中 MV 生成的动态及其与预后和治疗时间的关系。我们还将研究血浆 MV 水平和表型参数是否可以预测接受两项化学免疫治疗 (CIT) 临床试验的 CLL 患者的治疗结果。最后，我们将使用生化和遗传学方法剖析 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，我们将能够通过获得更明确的知识来解决我们的中心假设：体外和体内 CLL 中 MV 生成的动态、循环血浆 MV 预测 CLL 患者治疗结果的能力、异常信号传导的性质CLL BMSC 中的变化以及 MV 参数与疾病进展的关系。