PhosphoSer134 GR, TGF-β and 14-3-3-zeta cooperate to promote progression of Triple Negative Breast Cancer

项目摘要/摘要 三阴性乳腺癌(TNBC)的治疗选择有限。乳腺癌的这一亚型(BC) 缺乏目前用于靶向治疗的分子的表达，包括类固醇激素受体， 雌激素受体和孕激素受体，以及人表皮生长因子2受体。TNBC是 它是最具侵袭性、转移性和致命性的BC，占所有BC病例的40%。值得注意的是，15- 40%的TNBC患者表达糖皮质激素受体(GR)。GR是类固醇激素受体的一部分 对超家族及其在TNBC中的功能知之甚少。GR蛋白在翻译后大量存在 通过磷酸化事件进行修饰。GR的磷酸化对GR功能有多种影响，包括 改变与辅因子的相互作用，以及随后全球基因表达调控的变化。 具体地说，我们感兴趣的是Ser134上gr的磷酸化，这是一个独特的由细胞诱导的位点。 应激刺激，但不依赖于配体。值得注意的是，磷酸化Ser134GR对PTK6、a 蛋白酪氨酸激酶与晚期乳腺癌表型有关。我们的初步数据显示 与其他乳腺癌亚型相比，磷酸化Ser134 GR在TNBC中的表达更强。转化生长因子β是一个 与TNBC侵袭性相关的细胞因子。最近，我们发现转化生长因子β信号转导导致 GR在Ser134上被磷酸化，并促进其与支架蛋白14-3-3ζ的相互作用。 理解转化生长因子β、GR和14-3-3ζ之间合作以及随后PTK6上调的基础， 将使我们能够针对这种信号和转录复合体作为一种手段来阻止肿瘤的进展和 转移。在目标1中，我们建议测试14-3-3ζ作为磷酸Ser134 GR的潜在驱动因素的需求 靶基因调控与肿瘤细胞在TNBC模型中的迁移/侵袭和存活在目标2中，我们将 用小鼠证明PTK6作为肿瘤进展至转移的驱动因子的致癌作用 异种移植研究。拟议的研究和培训计划提供了一个严格的计划 完成我的医学博士学位。此外，它将为我提供成为一名成功的 学院派外科医生兼科学家。

PROJECT SUMMARY/ABSTRACT Therapeutic options for triple-negative breast cancer (TNBC) are limited. This subtype of breast cancer (BC) lacks expression of molecules currently exploited for targeted therapy including steroid hormone receptors, estrogen receptor and progesterone receptor, as well as human epidermal growth factor 2 receptor. TNBC is the most aggressive, metastatic, and deadly form of BC, and it accounts for up to 40% of all BC cases. Notably, 15- 40% of TNBC patients express glucocorticoid receptor (GR). GR is part of the steroid hormone receptor superfamily and its functions in TNBC are poorly understood. GR proteins are heavily post-translationally modified via phosphorylation events. Phosphorylation of GR has a variety of effects on GR function, including altered interaction with cofactors and subsequent changes in the regulation of global gene expression. Specifically, we are interested in phosphorylation of GR on Ser134, a site that is uniquely induced by cellular stress stimuli but independently of ligand. Notably, phosphoSer134 GR is critical for the expression of PTK6, a protein tyrosine kinase that is implicated in advanced breast cancer phenotypes. Our preliminary data indicates that phosphoSer134 GR expression is greater in TNBC relative to other breast cancer subtypes. TGFβ is a cytokine associated with aggressiveness of TNBC. Recently, we discovered that TGFβ signaling leads to phosphorylation of GR on Ser134 and promotes its interaction with the scaffolding protein 14-3-3ζ. Understanding the basis of cooperation between TGFβ, GR and 14-3-3ζ and subsequent upregulation of PTK6, will allow us to target this signaling and transcriptional complex as a means to block tumor progression and metastasis. In Aim 1, we propose to test the requirement for 14-3-3ζ as potential driver of phosphoSer134 GR target gene regulation and cancer cell migration/invasion and survival in TNBC models. In Aim 2, we will demonstrate the oncogenic roles of PTK6 as driver of tumor progression to metastasis in vivo using mouse xenograft studies. The proposed research and training plans provide a rigorous program for successful completion of my M.D./Ph.D. degrees. Moreover, it will provide me with the fundamentals to become a successful academic surgeon-scientist.