Crosstalk TGFbeta and HER2 (ErbB2) Signaling in Mammary Tumorigenesis

描述(申请人提供)：受体酪氨酸激酶HER2(ErbB2)的过度表达和转化生长因子？？(TGF？)信号转导都与乳腺癌向转移性更强的表型进展有关。HER2原癌基因的过表达可能参与了转化生长因子β的促癌作用。该方案的目的是研究转化生长因子和转化生长因子之间的相互作用、时间和空间串扰。以及HER2，它不仅涉及细胞内/细胞间，而且还涉及微环境事件。我们假设在HER2介导的转化中，转化生长因子？可以1)动态调节HER2的亚细胞分布和HER2细胞底物/信号转导系统；2)通过调节HER2的磷酸化和细胞转运来调节HER2信号的大小和幅度；3)改变细胞外基质和间质，创造一个促进肿瘤生长和转移的微环境；以及4)减弱依赖HER2的细胞对HER2治疗抑制剂的反应。了解转化生长因子之间串扰的时间和空间特征？HER2信号将揭示新的治疗靶点，并有可能优化目前HER2的治疗抑制剂。这一结果也将为抗转化生长因子？的综合治疗的前景提供帮助。和HER2在乳腺癌患者中的表达。将实现以下具体目标。具体目标1：确定是否激活了转化生长因子？受体在时间和空间上调控乳腺上皮细胞HER2信号，以及转化生长因子β诱导的细胞骨架重塑如何影响HER2的分布、转运和信号转导。特异目的2：探讨HER2与转化生长因子β相互作用是否需要Rac/Pak通路参与肿瘤的侵袭和存活，HER2是否为Pak1的底物，HER2是否与Pak1和活性的rac1共定位。具体目标3：确定是否存在转化生长因子？和HER2通过利用蛋白质组学方法修改微环境成分，以及这些方法是否有助于小鼠肿瘤的发生。具体目标4：确定是否激活了转化生长因子？信号转导通路可使乳腺癌细胞对HER2的治疗抑制剂产生耐药，以及PI3K和Rac/Pak信号通路在转化生长因子β诱导的耐药中的作用。

DESCRIPTION (provided by applicant): Overexpression of the receptor tyrosine kinase HER2 (ErbB2) and activation of transforming growth factor ??(TGF?) signaling are both associated with progression of breast cancers to a more metastatic phenotype. Overexpression of the HER2 proto-oncogene is permissive for the tumor promoting effects of TGF?. The objective of this proposal is to study the reciprocal, temporal and spatial crosstalk between TGF? and HER2, which involves not only intra-/intercellular but also microenvironmental events. We hypothesize that in HER2-mediated transformation, TGF? can 1) dynamically modulate HER2 subcellular distribution and the repertoire of HER2 cellular substrates/signal transducers; 2) regulate the magnitude and amplitude of HER2 signaling through the modulation of HER2 phosphorylation and cellular trafficking; 3) modify the ECM and stroma to create a microenvironment that facilitates tumor growth and metastasis; and 4) attenuate the response of HER2-dependent cells to therapeutic inhibitors of HER2. Understanding the temporal and spatial features of the crosstalk between TGF? and HER2 signaling will disclose new therapeutic targets, as well as potentially allow the optimization of current therapeutic inhibitors of HER2. The results will also shed light on the perspective of a combined therapy against TGF? and HER2 in breast cancer patients. The following specific aims will be pursued. Specific aim 1: to determine whether activated TGF? receptors spatially and temporally modulate HER2 signaling in mammary epithelial cells and how TGF? -induced cytoskeleton remodeling affects HER2 distribution, trafficking and signaling. Specific aim 2: to determine whether the Rac/Pak pathway is required for the invasiveness and survival mediated by the interaction between HER2 and TGF?, whether HER2 is a substrate of Pak1 and whether HER2 colocalizes with Pak1 and active Rac1 in primary breast tumors. Specific aim 3: to determine whether TGF? and HER2 modify microenvironmental components by utilizing proteomic approaches and whether these contribute to tumorigenesis in mice. Specific aim 4: to determine whether activated TGF? signaling can confer resistance to therapeutic inhibitors of HER2 in mammary cancer cells and the role of PI3K and Rac/Pak pathways in TGF? -conferred resistance.