The role of the protein tyrosine phosphatase PRL3 in leukemia development

描述（由申请人提供）：复发性T细胞急性淋巴细胞白血病（T-ALL）的侵袭性和不可预测性是一个主要的临床挑战，在很大程度上是由于高毒性和无效的化疗。治疗的进一步进展将需要对T- ALL发展和复发的分子基础的详细理解。为此，我在斑马鱼中完成了一项高度创新的筛选，以确定与T-ALL进展相关的基因，并发现蛋白酪氨酸磷酸酶PRL-3通常在单个T-ALL细胞中扩增，因为它们随着时间的推移形成复发的能力增加。在转基因动物中，PRL-3过表达显著增强原发性T-ALL的发展和复发形成。我发现PRL-3在人类T-ALL的一个子集中扩增，并且在大多数T-ALL患者样本中高度表达。这些细胞还通过诱导细胞凋亡对PRL-3敲低敏感。这些结果表明PRL-3活性在T-ALL恶性肿瘤中具有重要作用，并且PRL-3及其底物可能代表用于治疗T-ALL的新的治疗靶点。本提案的目的是1）定义PRL-3对T-ALL进展和复发的贡献，2）鉴定PRL-3驱动T-ALL恶性肿瘤的机制。这一目标将通过两个具体目标实现。在该奖项的K99阶段，我将完成目标1，在那里我将检查PRL-3功能获得和功能丧失在斑马鱼T-ALL发展的各个阶段的影响，包括从胸腺侵入，内渗，增殖和复发，我还将测试PRL-3敲低对小鼠异种移植模型中人类细胞的影响。在这个阶段，我将学习直接成像活体动物的癌症进展和开发小鼠原位白血病异种移植物的技术。有了这些知识，在R 00阶段，我将完成目标2，在那里我将确定T-ALL细胞中PRL-3的靶底物，并使用体内和体外上位性实验测试这些基因和通路对T-ALL恶性肿瘤的贡献。总之，这项工作将为开发小分子PRL-3和途径抑制剂用于T-ALL的潜在治疗奠定基础。该奖项的指导阶段将在斑马鱼癌症模型专家大卫兰格瑙博士和白血病研究领域国际公认的领导者托马斯卢博士的指导下进行。他们的指导记录，加上密集的教学组成部分和严格和培育学术环境所提供的研究界的马萨诸塞州总医院和哈佛医学院为我的成功提供了最好的机会，因为我过渡到成为一名独立的研究者。

DESCRIPTION (provided by applicant): The aggressive and unpredictable nature of relapsed T-cell acute lymphoblastic leukemia (T-ALL) represents a major clinical challenge, in large part due to highly toxic and ineffective chemotherapies. Further advances in therapy will require a detailed understanding of the molecular underpinnings of T- ALL development and relapse. To this end, I have completed a highly innovative screen in zebrafish to identify genes associated with T-ALL progression and have found that the protein tyrosine phosphotase PRL-3 was commonly amplified in single T-ALL cells as they developed increased ability to form relapse over time. In transgenic animals, PRL-3 over-expression significantly enhanced primary T-ALL development and relapse formation. I have found that PRL-3 amplified in a subset of human T-ALL and is highly expressed by a majority of T-ALL patient samples. These cells are also sensitive to PRL-3 knock-down through the induction of apoptosis. These results imply that PRL-3 activity has an important role in T-ALL malignancy, and that PRL-3 and its substrates may represent novel therapeutic targets for the treatment of T-ALL. The objectives of this proposal are to 1) define the contribution of PRL-3 to T- ALL progression and relapse and 2) identify the mechanism by which PRL-3 drives T-ALL malignancy. This objective will be achieved through two specific aims. During the K99 phase of this award, I will complete Aim 1, where I will examine the effect of PRL-3 gain-of-function and loss-of-function in various stages of T-ALL development in zebrafish, including invasion from the thymus, intravasation, proliferation and relapse, and I will also test the effects of PRL-3 knock-down on human cells in a murine xenograft model. During this phase, I will learn techniques to directly image cancer progression in live animals and to develop orthotopic leukemia xenografts in mice. With this knowledge in hand, during the R00 phase I will complete Aim 2, where I will identify the target substrates of PRL-3 in T-ALL cells, and test the contribution of these genes and pathways to T-ALL malignancy using in vivo and in vitro epistasis experiments. In total, this work will lay the foundation for the development of small molecule PRL-3 and pathway inhibitors for potential therapeutic use in T-ALL. The mentored phase of this award will occur under the guidance of Dr. David Langenau, an expert in zebrafish models of cancer, and Dr. Thomas Look, an internationally recognized leader in the field of leukemia research. Their proven track record of mentorship, coupled with an intensive didactic component and the rigorous and nurturing academic environment offered by the research community of Massachusetts General Hospital and Harvard Medical School offer the best opportunity for my success as I transition to becoming an independent investigator.