ErbB receptor signaling via small G-proteins in breast cancer

乳腺癌中通过小 G 蛋白进行的 ErbB 受体信号传导

• 批准号: 8468659
• 负责人: MARCELO G. KAZANIETZ
• 金额: $ 35.16万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-15 至 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8468659
• 关键词: Actins; Address; Affect; Anchorage-Independent Growth; Animal Model; Biological Assay; Breast Cancer Cell; Breast Cancer Model; Breast Carcinoma; CXCR4 gene; Cancer cell line; Cell model; Cell physiology; Cells; Cytoskeleton; Disease; Disease Progression; Dissociation; Down-Regulation; ERBB2 gene; Epidermal Growth Factor; Epidermal Growth Factor Receptor; ErbB4 gene; Estrogen Antagonists; Etiology; Family; Fluorescence Resonance Energy Transfer; G Protein-Coupled Receptor Signaling; G-Protein-Coupled Receptors; GTPase-Activating Proteins; Gene Amplification; Gene Mutation; Goals; Guanine Nucleotide Exchange Factors; Guanosine Triphosphate; Guanosine Triphosphate Phosphohydrolases; Heregulin; Human; Isoenzymes; Lead; Ligands; Malignant Neoplasms; Mammary Neoplasms; Mammary gland; Mediating; Mediator of activation protein; Membrane; Modeling; Molecular; Monomeric GTP-Binding Proteins; Mus; Mutate; Neoplasm Metastasis; Normal Cell; Nude Mice; PTEN gene; Pathway interactions; Pertussis Toxin; Phosphatidylinositols; Play; Properdin; Property; Protein Tyrosine Kinase; Proteins; RNA Interference; Receptor Protein-Tyrosine Kinases; Receptor Signaling; Relative (related person); Resistance; Role; Signal Transduction; Stimulation of Cell Proliferation; Testing; Therapeutic; Tissue Banking; Tissue Banks; Toxin; Transactivation; Tumorigenicity; Up-Regulation; base; cell motility; chemokine; inhibitor/antagonist; malignant breast neoplasm; member; migration; mouse model; neutrophil; novel; outcome forecast; overexpression; prevent; prognostic; public health relevance; receptor; receptor coupling; response; rho; rho GTPase-activating protein; tripolyphosphate; tumor; tumor progression; tumorigenesis; tumorigenic; wortmannin

DESCRIPTION (provided by applicant): The human epidermal growth factor (EGF) family of tyrosine kinase receptors consists of ErbB1 (EGFR), ErbB2 (Neu), ErbB3, and ErbB4, and plays key roles in cancer progression. Dysregulation of ErbB signaling due to hyperactivation of receptors (such as mutated EGFR or ErbB2 overexpression), overexpression of ligands (such as TGF-? or heregulins), or augmented downstream signaling (such as enhanced PI3K signaling) plays a major role in the etiology of breast cancer. We found that ligand stimulation of ErbB1 and ErbB3 receptors leads to a strong activation of the small GTPase Rac1 to promote mitogenesis and motility. The search for Rac-GEFs that mediate Rac1 activation by ErbB ligands in breast cancer cells revealed a prominent role for phosphatidylinositol-3,4,5-triphosphate-dependent Rac exchanger-1 (P-Rex1), a Rac-GEF originally identified in neutrophils but not studied in any cancer so far. Strikingly, P-Rex1 is highly expressed in most breast cancer cell lines as well as in tumors. P-Rex1 is a PI3K- and G??-dependent Rac-GEF, and coincidentally, ErbB receptor-mediated activation of Rac1 is inhibited by Pertusis toxin, which prevents G23 subunit release from heterotrimeric Gi proteins, by the PI3K inhibitor wortmannin, and by inhibition/depletion of PI3K?, a class Ib PI3K that is activated by G?? subunits. Moreover, ErbB3-induced activation of Rac1 is dependent on the transactivation of CXCR4, a Gi-coupled receptor widely implicated in breast cancer progression, and Rac1 activation by direct stimulation of CXCR4 with the chemokine SDF-11 also depends on P-Rex1. Therefore, P-Rex1 is a common mediator of Rac activation by ErbB receptors and GPCRs in breast cancer cells. In Specific Aim 1 we will investigate whether ligand stimulation of ErbB receptors can promote the activation of P-Rex1 in breast cancer cells, and assess the functional consequences for such activation, including actin cytoskeleton reorganization, migration, and proliferation. Translocation studies as well as FRET approaches will be used to address the relative contribution of discrete PI3K isozymes and the CXCR4-G?? pathway to P-Rex1 and Rac1 activation. In Specific Aim 2 we will determine whether RNAi depletion of P-Rex1 affects tumorigenicity and metastatic dissemination of breast cancer cells driven by overexpression of an ErbB3 ligand. We will also assess the involvement of P-Rex1 in anti-estrogen resistance. In Specific Aim 3 we will determine if Rac signaling via P-Rex1 contributes to ErbB2-driven tumorigenesis and metastasis, and whether this is mediated by the CXCR4-G??-PI3K? pathway. We will generate mammary-specific mouse models for P-Rex1 overexpression and determine whether it can lead to tumor formation or cooperate with ErbB2 overexpression. In Specific Aim 4 the goal is to determine whether P-Rex1 is a hallmark of human breast cancer, and P-Rex1 expression in human tumors correlates with signaling parameters. The identification of P-Rex1 as an effector of ErbB receptors may have major relevance for understanding the molecular basis and etiology of breast cancer as well as significant prognostic and therapeutic implications.

描述（由申请人提供）：酪氨酸激酶受体的人类表皮生长因子（EGF）家族由ERBB1（EGFR），ERBB2（NEU），ERBB3和ERBB4组成，并在癌症进展中起关键作用。因受体过度激活（例如突变的EGFR或ERBB2过表达），配体过表达（例如TGF-？或此处的gle蛋白）或增强的下游信号传导（例如PI3K信号增强）在乳腺癌的病因中起主要作用的作用。我们发现，ERBB1和ERBB3受体的配体刺激导致小GTPase Rac1的强烈激活，以促进有丝分裂和运动。搜索RAC-GEF在乳腺癌细胞中介导RAC1激活的RAC-GEF，发现磷脂酰肌醇-3,4,5-三磷酸依赖性RAC Exchanger-1（P-Rex1）的重要作用是最初在中性粒细胞中鉴定出的RAC-GEF，但在任何癌症中都没有研究。令人惊讶的是，P-REX1在大多数乳腺癌细胞系和肿瘤中都高度表达。 P-REX1是PI3K和G ??-依赖性RAC-GEF，偶然地，ERBB受体介导的Rac1的激活受到查环毒素的抑制，它阻止了pi3K抑制剂wortmannin和piby piby/debion/debion/deby pretiion/depletion the g23亚蛋白中的G23亚基GI蛋白，并通过PI3K抑制剂/debion iNbion/debion iNbion/debion？那是由g激活的？亚基。此外，ERBB3诱导的RAC1激活取决于CXCR4的反式激活，GI偶联受体广泛与乳腺癌的进展有关，而Rac1通过直接刺激CXCR4用趋化因子SDF-11进行CXCR4激活也取决于P-REX1。因此，P-Rex1是ERBB受体和GPCR在乳腺癌细胞中激活RAC激活的常见介体。在特定目标1中，我们将研究ERBB受体的配体刺激是否可以促进乳腺癌细胞中P-Rex1的激活，并评估这种激活的功能后果，包括肌动蛋白细胞骨架的重组，迁移和增殖。易位研究以及FRET方法将用于解决离散PI3K同工酶和CXCR4-G的相对贡献？ P-Rex1和Rac1激活的途径。在特定目标2中，我们将确定P-REX1的RNAi耗竭是否会影响由ERBB3配体过表达驱动的乳腺癌细胞的肿瘤性和转移性传播。我们还将评估P-Rex1在抗雌激素耐药性中的参与。在特定的目标3中，我们将确定RAC通过P-REX1信号传导是否有助于ERBB2驱动的肿瘤发生和转移，以及这是否是由CXCR4-G ?? - PI3K介导的？路径。我们将生成用于P-Rex1过表达的乳腺特异性小鼠模型，并确定它是否可以导致肿瘤形成或与ERBB2过表达合作。在特定目标4中，目标是确定p-rex1是否是人类乳腺癌的标志，而人类肿瘤中的p-rex1表达与信号参数相关。将P-REX1鉴定为ERBB受体的效应子可能与理解乳腺癌的分子基础和病因以及明显的预后和治疗意义具有重要意义。