The role of HEF1 protein in division and invasion of metastatic breast cancer

描述(由申请人提供)：这项提案将检验这样一种假设，即乳腺肿瘤中HEF1基因的上调是癌症转移的重要贡献因素。这是基于升高的HEF1驱动增殖和侵袭的能力。对于侵袭，细胞变得越来越能动，并获得入侵周围组织的能力，从而使转移成为可能。在过去的一年里，一系列研究已经提名HEF1蛋白作为促进肿瘤转移行为的重要开关。这些研究已经确定HEF1是转移性乳腺癌中上调的一小部分基因的一个组成部分，表明HEF1对胶质母细胞瘤的侵袭性很重要，并确定在超过30%的转移性黑色素瘤中发生HEF1上调。在这个提案中，我们将解决两个基本问题：1)HEF1的缺失或过度表达如何影响Aura的激活，以及2)HEF1如何调节乳腺癌细胞的侵袭？在回答这些问题的具体实验中，目标1将使用机械性的、基于细胞的分析来研究HEF1如何调节Aura的降解。我们将测试HEF1保护AURA免受泛素依赖的蛋白小体降解的假设，并确定HEF1-AURA复合体对临床相关AURA抑制剂疗效的影响。目的2明确HEF1‘S侵袭促进能力的分子机制。我们将检验这样的假设，即HEF1激活的AURA激活组蛋白脱乙酰基酶HDAC6，并促进插叶植物种子成分皮质酮的脱乙酰化。在目标3中，我们将使用针对HEF1的可诱导shRNA原位移植小鼠模型和现代多模式非侵入性荧光/生物发光成像技术来验证HEF1表达升高对乳腺癌转移有显著贡献的假说，以建立HEF1驱动人类癌症生长和转移的分子机制。这些实验的最终目标是提高人类患者癌症的诊断和治疗水平。

DESCRIPTION (provided by applicant): This proposal will test the hypothesis that up-regulation of the HEF1 gene in breast tumors is an important contributing factor for cancer metastasis. This is based on the ability of elevated HEF1 to drive proliferation and invasion. For invasion, cells become increasingly motile and acquire the ability to invade surrounding tissue which enables metastasis. A series of studies within the past year have nominated the HEF1 protein as an essential switch for pro-metastatic behavior in tumors. These studies have identified HEF1 as a component of a small "signature" of genes upregulated in metastasizing breast adenocarcinomas, shown HEF1 is important for glioblastoma invasiveness, and determined that upregulation of HEF1 occurred in more than 30% of metastatic melanomas. In this proposal, we will address two basic questions: 1) How does absence or overexpression of HEF1 condition AurA activation, and 2) How does HEF1 regulate invasion in breast cancer cells? In specific experiments to answer these questions, Aim 1 will use mechanistic, cell-based assays to investigate how HEF1 regulates AurA degradation. We will test the hypothesis that HEF1 protects AurA from ubiquitin-dependent proteosome degradation and determine the impact of the HEF1-AurA complex on efficacy of clinically relevant AurA inhibitors. Aim 2 will define the molecular mechanisms underlying HEF1's invasion promoting abilities. We will test the hypothesis that HEF1-activated AurA activates histone deacetylase HDAC6 and promotes deacetylation of invadopodia seeding component- cortactin. In Aim 3 we will test the hypothesis that elevated HEF1 expression contributes significantly to breast cancer metastasis using orthotopic mouse xenograft models with inducible shRNAs against HEF1 and modern multimodal non-invasive fluorescent/bioluminescent imaging technology to establish molecular mechanisms of HEF1-driven tumor growth and metastasis in human cancer. The ultimate goal of these experiments is to improve the diagnosis and treatment of cancer in human patients.