The Role of PI3Kbeta in Breast Cancer Metastasis

PI3Kbeta 在乳腺癌转移中的作用

基本信息

批准号：
9125560
负责人：
ANNE R BRESNICK
金额：
$ 35.4万
依托单位：
ALBERT EINSTEIN COLLEGE OF MEDICINE, INC
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-08-01 至 2020-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9125560
关键词：
1-Phosphatidylinositol 3-Kinase Actins Affect Apoptosis Binding Binding Sites Biochemical Biological Biology Breast Cancer Cell Breast cancer metastasis Cell Proliferation Cell Survival Cells Chemicals Complex Coupling Data Defect Development Dimerization Disease Progression Drug Targeting Enzymes Epithelial Extracellular Matrix Extravasation G Protein-Coupled Receptor Signaling G-Protein-Coupled Receptors Genetic Genetic Models Growth Factor Gene Histology Human Immune system In Vitro Integrins Invaded Knock-in Mouse Lead Link Malignant Neoplasms Mammary gland Matrix Metalloproteinases Measures Mediating Membrane Metabolism Metastatic Neoplasm to the Lung Metastatic breast cancer Modeling Mouse Mammary Tumor Virus Mus Mutant Strains Mice Mutate Mutation Neoplasm Metastasis Normal Cell PIK3CA gene PTEN gene Paracrine Communication Penetrance Peptides Pharmaceutical Preparations Phenotype Phosphotransferases Play Prevention Prevention approach Primary Neoplasm Production Proteins Recruitment Activity Role S-Phase Fraction SCID Mice Signal Transduction Site Source Stromal Cells Stromal Neoplasm Structure System Testing Therapeutic Tissues Tumor Cell Invasion Tyrosine Work Xenograft Model base cancer cell chemokine cytokine design gene product human disease in vivo inhibitor/antagonist insight macrophage malignant breast neoplasm mortality mouse model mutant neoplastic cell novel public health relevance research study src Homology Region 2 Domain tumor tumor growth tumor progression

1-Phosphatidylinositol 3-Kinase Actins Affect Apoptosis Binding Binding Sites Biochemical Biological Biology Breast Cancer Cell Breast cancer metastasis Cell Proliferation Cell Survival Cells Chemicals Complex Coupling Data Defect Development Dimerization Disease Progression Drug Targeting Enzymes Epithelial Extracellular Matrix Extravasation G Protein-Coupled Receptor Signaling G-Protein-Coupled Receptors Genetic Genetic Models Growth Factor Gene Histology Human Immune system In Vitro Integrins Invaded Knock-in Mouse Lead Link Malignant Neoplasms Mammary gland Matrix Metalloproteinases Measures Mediating Membrane Metabolism Metastatic Neoplasm to the Lung Metastatic breast cancer Modeling Mouse Mammary Tumor Virus Mus Mutant Strains Mice Mutate Mutation Neoplasm Metastasis Normal Cell PIK3CA gene PTEN gene Paracrine Communication Penetrance Peptides Pharmaceutical Preparations Phenotype Phosphotransferases Play Prevention Prevention approach Primary Neoplasm Production Proteins Recruitment Activity Role S-Phase Fraction SCID Mice Signal Transduction Site Source Stromal Cells Stromal Neoplasm Structure System Testing Therapeutic Tissues Tumor Cell Invasion Tyrosine Work Xenograft Model base cancer cell chemokine cytokine design gene product human disease in vivo inhibitor/antagonist insight macrophage malignant breast neoplasm mortality mouse model mutant neoplastic cell novel public health relevance research study src Homology Region 2 Domain tumor tumor growth tumor progression

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项目摘要

DESCRIPTION (provided by applicant): Tumor metastasis is the major cause of mortality in human breast cancer. Previous studies have shown that breast cancer metastasis is driven by paracrine signaling between tumor cells and stromal cells, which promotes invasion, intravasation, extravasation and tumor growth at secondary sites. This paracrine signaling is dependent on the reciprocal production of growth factors, cytokines and chemokines produced by stromal cells and tumor cells, many of which signal via G-protein-coupled receptors (GPCRs). We now present extensive preliminary data showing that GPCR signaling to PI3Kβ is critical for tumor cell invasion, intravasation and extravasation. Importantly, loss of GPCR signaling to PI3Kβ has a more severe phenotype on tumor intravasation and extravasation in vivo than loss of kinase activity, suggesting that inhibition of p110β-Gβγ binding might provide an alternative therapeutic approach for the prevention of breast cancer metastasis. This proposal examines the role of PI3Kβ in breast cancer metastasis, using both in vitro and in vivo approaches. The first aim comprises mechanistic studies to evaluate the role of PI3Kβ in the formation of invadopodia, which allow tumor cells to invade into surrounding tissue. We will focus on two models of p110β function in invadopodia maturation: (a) as a local source of PI[3,4,5]P3, whose metabolism to PI[3,4]P2 recruits the critical invadopodia protein Tks5; and (b) as a regulator of integrin signaling, which is important for invadopodia maturation and MMP secretion. Aim 2 examines how p110β integrates upstream signals from GPCRs, RTKs and Rac1, and examines the role of Rac1 signaling to PI3Kβ in breast cancer metastasis. In particular, we find that mutation of the Gβγ binding site in p110β has no effect on Rac1GTP binding and activation of p110β in vitro, but blocks PI3Kβ activation by constitutively active Ra1 in cells. Similarly, inhibitors that block the binding of the p85 regulatory subunit to tyrosine-phosphorylated proteins also inhibit PI3Kβ activation by CA-Rac. We will explore two hypotheses to explain these data: first, that Rac binding to PI3Kβ in cells requires the targeting of PI3Kβ to the membrane, and second, that activation of PI3Kβ by Gβγ or SH2-mediated interactions sensitizes PI3Kβ to Rac. We will also directly test the role of Rac binding to p110β in breast cancer metastasis using in vitro and in vivo xenograft models. Finally, we will study the role of PI3Kβ in breast cancer metastasis using an established genetic mouse model, MMTV-PyMT, which develops mammary epithelial tumors with high penetrance and has an intact immune system. We will cross PyMT mice to a knock-in mouse expressing the GPCR-uncoupled mutant of p110β, to definitively establish the role of GPCR signaling to PI3Kβ in tumor progression and metastasis. Altogether, these studies will lead to important new insights into the basic biology of PI3Kβ, and the role of this complex signaling enzyme in breast cancer metastasis.

描述（通过应用提供）：肿瘤转移是人类乳腺癌死亡率的主要原因。先前的研究表明，乳腺癌转移是由肿瘤细胞和基质细胞之间的旁分泌信号传导驱动的，肿瘤细胞和基质细胞之间促进了次要部位的侵袭，侵入，渗入，渗出和肿瘤生长。该旁分泌信号传导取决于基质细胞和肿瘤细胞产生的生长因子，细胞因子和趋化因子的相互产生，其中许多通过G蛋白偶联受体（GPCR）信号。现在，我们提供了广泛的初步数据，表明对PI3Kβ的GPCR信号对于肿瘤细胞侵袭，侵入和渗出至关重要。重要的是，与激酶活性的丧失相比，对PI3Kβ的丧失对PI3Kβ的肿瘤插入和渗出的表型比激酶活性的丧失更为严重，这表明抑制p110β-Gβγ的结合可能会提供一种预防乳腺癌转移的替代治疗方法。该提案使用体外和体内方法研究了PI3Kβ在乳腺癌转移中的作用。第一个目标包括评估PI3Kβ在Invadopodia形成中的作用的机械研究，这使肿瘤细胞可以侵入周围的组织。我们将重点关注Invadodia成熟中P110β功能的两个模型：（a）作为PI的局部来源[3,4,5] P3，其代谢对PI [3,4] P2募集了关键的临界Invadopodia蛋白TKS5；（b）作为整联蛋白信号传导的调节剂，这对于成熟和MMP分泌非常重要。 AIM 2检查P110β如何整合了GPCR，RTK和RAC1的上游信号，并检查RAC1信号对PI3Kβ在乳腺癌转移中的作用。特别是，我们发现p110β中Gβγ结合位点的突变对Rac1GTP结合和体外P110β的激活没有影响，但是通过组成性活性RA1在细胞中阻止PI3Kβ激活。同样，阻断p85调节亚基与酪氨酸磷酸化蛋白的结合的抑制剂也抑制了CA-RAC的PI3Kβ激活。我们将探讨两个假设来解释这些数据：首先，RAC与细胞中的PI3Kβ结合需要靶向 PI3Kβ向膜上的大量，其次是Gβγ或SH2介导的相互作用对PI3Kβ的激活感应PI3Kβ对RAC。我们还将直接测试RAC与P110β结合的作用在乳腺癌转移中，使用体外和体内特征模型。最后，我们将研究 PI3Kβ在乳腺癌转移中使用已建立的遗传小鼠模型MMTV-PYMT在乳腺癌转移中的作用，该模型MMTV-PYMT发展具有高渗透率且具有完整免疫系统的乳腺上皮肿瘤。我们将越过PYMT小鼠到表达p110β的GPCR脉冲突变体的敲入小鼠，以确定确定GPCR信号对PI3Kβ在肿瘤进展和转移中的作用。总的来说，这些研究将导致对PI3Kβ基本生物学的重要新见解，以及这种复杂的信号传导酶在乳腺癌转移中的作用。