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

描述（由申请人提供）：本提案将检验以下假设：乳腺肿瘤中HEF 1基因的上调是癌症转移的重要促成因素。这是基于升高的HEF 1驱动增殖和侵袭的能力。对于侵袭，细胞变得越来越能动，并获得侵袭周围组织的能力，这使得转移成为可能。过去一年的一系列研究已经将HEF 1蛋白提名为肿瘤促转移行为的重要开关。这些研究已经确定HEF 1是转移性乳腺腺癌中上调基因的小“签名”的组分，显示HEF 1对胶质母细胞瘤侵袭性很重要，并确定HEF 1的上调发生在超过30%的转移性黑色素瘤中。在这个提议中，我们将解决两个基本问题：1）HEF 1的缺失或过表达如何调节AurA激活，以及2）HEF 1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，Aim 1将使用基于细胞的机械分析来研究HEF 1如何调节AurA降解。我们将测试HEF 1保护AurA免受泛素依赖性蛋白体降解的假设，并确定HEF 1-AurA复合物对临床相关AurA抑制剂疗效的影响。目的二是阐明HEF 1促侵袭能力的分子机制。我们将测试HEF 1激活的AurA激活组蛋白脱乙酰酶HDAC 6并促进入侵伪足种子组分-coronin的脱乙酰化的假设。在目标3中，我们将使用具有针对HEF 1的诱导型shRNA的原位小鼠异种移植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HEF 1表达升高显著促进乳腺癌转移的假设，以建立HEF 1驱动的人类癌症肿瘤生长和转移的分子机制。这些实验的最终目标是改善人类患者癌症的诊断和治疗。 公共卫生相关性：HEF 1蛋白表达的变化驱动了超过30%的人类黑色素瘤的转移，并与乳腺癌的转移行为有关。拟议的工作将阐明HEF 1在转移性癌症进展中的作用，并揭示可用于治疗的癌细胞脆弱性。此外，拟议的工作将直接测试现有的、临床验证的靶向AurA和HDAC 6的药物对转移形成的影响，从而为在肿瘤转移之前使用这些药物作为新的抗侵袭措施提供基础。

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. PUBLIC HEALTH RELEVANCE: Changes in HEF1 protein expression drive metastasis in more than 30% of human melanomas, and have been linked to metastatic behavior in breast cancer. The proposed work will elucidate the action of HEF1 in metastatic cancer progression, and reveal points of cancer cell vulnerability that can be therapeutically exploited. Further, the proposed work will directly test existing, clinically validated drugs targeting AurA and HDAC6 for effects on metastases formation, and may thus provide basis for using these agents as new anti-invasive measures prior to tumor metastasis.