DISSECTING ROLES OF MTBP IN OSTEOSARCOMA METASTASIS

剖析 MTBP 在骨肉瘤转移中的作用

• 批准号: 7610681
• 负责人: Tomoo Iwakuma
• 金额: $ 33.52万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7610681
• 关键词: Affect; Alleles; Attenuated; BAX gene; Bax protein; Binding; Binding Proteins; CDKN1A gene; Cell Cycle; Computer Retrieval of Information on Scientific Projects Database; Development; Funding; G1 Arrest; Genetic Transcription; Goals; Grant; Institution; Knock-out; Knockout Mice; Malignant Neoplasms; Metastatic Osteosarcoma; Mus; Mutate; Neoplasm Metastasis; Numbers; Osteoblasts; Pathway interactions; Patients; Play; Proteins; Protocols documentation; Research; Research Personnel; Resources; Role; Source; Stress; TP53 gene; Therapeutic; Tumor Suppressor Proteins; United States National Institutes of Health; Work; base; design; in vivo; inhibitor/antagonist; mutant; novel; oncoprotein p21; osteosarcoma; outcome forecast; tumor; yeast two hybrid system

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Our long-term goal is to elucidate the impact of the Mdm2-p53 pathway in vivo on tumor development as a necessary prerequisite to the development of therapeutic protocols for attenuating cancer. p53 functions as a tumor suppressor and exerts this function by activating numerous downstream targets such as p21, BAX, PUMA, GADD45 as a transcription factor1. Mdm2 is a major inhibitor of p53 through physical binding and induction of p53 degradation2. The p53 gene is mutated in more than 50% of tumors, and Mdm2 is highly expressed in a variety of tumors, stressing the importance of the Mdm2-p53 pathway in tumor development 3-6. It should be noted that a significant number of tumors have wild-type p53 with Mdm2 over-expression. Interestingly, some patients with tumors in which p53 gene is mutated and Mdm2 is over-expressed are known to have a poorer prognosis, compared to patients with mutant p53 alone in tumors7, 8. These results suggest that Mdm2 also has p53-independent roles in tumor development. Recently, Mdm2 is found to inhibitory interact with other tumor suppressors such as Rb, PML, and p73, which may contribute to p53-independent roles of Mdm2 in tumor development9-15. One can assume that any proteins that affect Mdm2 function may have an impact on tumor development. Mdm2 Binding Protein (MTBP) was isolated by Boyd MT et al.16 using the yeast two hybrid system with Mdm2 as bait. Over-expression of MTBP causes G1 arrest of cell cycle, but the effect is nullified by simultaneous over-expression of Mdm2. Our working hypothesis is that MTBP plays a critical role in tumor development and metastasis. This hypothesis is based on our preliminary results using a conventional mtbp knockout mouse in which we observed that (1) 30% of mtbp heterozygous mice spontaneously developed tumors within 22 months, and (2) doubly heterozygous knockout mice for mtbp and p53 developed metastatic osteosarcomas. Based on these observations, the focus of this proposal is on the roles of MTBP in osteosarcoma metastasis and the functional characterization of this protein. The specific aims are designed to provide a comprehensive assessment of novel functions of MTBP, especially in osteosarcoma metastasis. Aim 1. To characterize osteosarcomas induced by loss of mtbp. Aim 2. To generate and characterize mice with conditional mtbp and/or p53 knockout alleles, specifically in osteoblasts. Aim 3. To isolate MTBP interacting proteins.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目及 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 我们的长期目标是阐明体内 Mdm2-p53 通路对肿瘤发展的影响，这是制定减轻癌症的治疗方案的必要先决条件。 p53 发挥肿瘤抑制因子的作用，并通过激活众多下游靶标（例如 p21、BAX、PUMA、GADD45）作为转录因子来发挥此功能1。 Mdm2 通过物理结合和诱导 p53 降解，成为 p53 的主要抑制剂2。 p53 基因在超过 50% 的肿瘤中发生突变，并且 Mdm2 在多种肿瘤中高表达，强调了 Mdm2-p53 通路在肿瘤发展中的重要性 3-6。值得注意的是，大量肿瘤具有野生型 p53 且 Mdm2 过度表达。有趣的是，与肿瘤中仅具有突变 p53 的患者相比，一些 p53 基因突变且 Mdm2 过表达的肿瘤患者的预后较差7, 8。这些结果表明，Mdm2 在肿瘤中也具有独立于 p53 的作用。肿瘤的发展。最近，发现 Mdm2 与其他肿瘤抑制因子（例如 Rb、PML 和 p73）具有抑制性相互作用，这可能有助于 Mdm2 在肿瘤发展中发挥独立于 p53 的作用9-15。人们可以假设任何影响 Mdm2 功能的蛋白质都可能对肿瘤的发展产生影响。 Mdm2 结合蛋白 (MTBP) 由 Boyd MT 等人 16 使用酵母二杂交系统以 Mdm2 作为诱饵分离。 MTBP 的过度表达会导致细胞周期 G1 期停滞，但该效应会被 Mdm2 同时过度表达所抵消。我们的工作假设是 MTBP 在肿瘤的发展和转移中发挥着关键作用。这一假设基于我们使用传统 mtbp 敲除小鼠的初步结果，其中我们观察到 (1) 30% 的 mtbp 杂合小鼠在 22 个月内自发产生肿瘤，(2) mtbp 和 p53 双杂合敲除小鼠产生转移性骨肉瘤。基于这些观察，本提案的重点是 MTBP 在骨肉瘤转移中的作用以及该蛋白的功能表征。具体目标旨在对 MTBP 的新功能进行全面评估，特别是在骨肉瘤转移中。 目标 1. 表征由 mtbp 缺失引起的骨肉瘤。 目标 2. 产生并表征具有条件性 mtbp 和/或 p53 敲除等位基因的小鼠，特别是在成骨细胞中。 目标 3. 分离 MTBP 相互作用蛋白。