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：
9324335
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/9324335
关键词：
1-Phosphatidylinositol 3-Kinase Actins Affect Alpha Cell Apoptosis Binding Binding Sites Biochemical Biological Biology Blood Vessels Breast Cancer Model Breast Cancer Prevention 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 Histology Human Immune system In Vitro Integrins Invaded Knock-in Mouse Link Malignant Neoplasms Mammary gland 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 PIK3CG gene PTEN gene Paracrine Communication Penetrance Peptides Pharmaceutical Preparations Phenotype Phosphotransferases Play 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 dimer experimental study gene product human disease in vivo inhibitor/antagonist insight macrophage malignant breast neoplasm mortality mouse model mutant neoplastic cell novel public health relevance src Homology Region 2 Domain tumor tumor growth tumor progression

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（由申请人提供）：肿瘤转移是人类乳腺癌死亡的主要原因，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驱动的，其促进侵袭、内渗、外渗和肿瘤生长。这种旁分泌信号依赖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，其中许多信号通过G 蛋白偶联受体 (GPCR) 现在提供了大量初步数据，表明 PI3Kβ 的 GPCR 信号传导对于肿瘤细胞侵袭、内渗和外渗至关重要。重要的是，PI3Kβ 的 GPCR 信号传导缺失对肿瘤内渗和外渗具有更严重的表型。体内外渗多于激酶活性丧失，表明抑制 p110β-Gβγ 结合可能会提供预防乳腺癌转移的替代治疗方法该提案利用体外和体内方法研究 PI3Kβ 在乳腺癌转移中的作用，第一个目标包括评估 PI3Kβ 在侵袭伪足形成中的作用的机制研究。，这使得肿瘤细胞能够侵入周围组织，我们将重点关注 p110β 在侵入伪足成熟过程中的两种功能模型：(a) 作为局部来源。 PI[3,4,5]P3，其代谢为 PI[3,4]P2，招募关键的侵袭伪足蛋白 Tks5；(b) 作为整合素信号传导的调节剂，这对于侵袭伪足的成熟和 MMP Aim 2 的分泌很重要。检查 p110β 如何整合来自 GPCR、RTK 和 Rac1 的上游信号，并检查 Rac1 信号传导至 PI3Kβ 在乳腺癌中的作用特别是，我们发现 p110β 中 Gβγ 结合位点的突变对 Rac1GTP 结合和 p110β 的体外激活没有影响，但通过细胞中组成型活性 Ra1 阻断 PI3Kβ 激活，类似地，阻断 p85 结合的抑制剂。酪氨酸磷酸化蛋白的调节亚基也抑制 CA-Rac 激活 PI3Kβ 我们将探讨两个假设来解释这些数据：首先， Rac 与细胞中 PI3Kβ 的结合需要靶向其次，Gβγ 或 SH2 介导的相互作用对 PI3Kβ 的激活使 PI3Kβ 对 Rac 敏感，我们还将直接测试 Rac 与 p110β 结合的作用。最后，我们将研究使用体外和体内异种移植模型的乳腺癌转移。使用遗传小鼠模型 MMTV-PyMT 来研究 PI3Kβ 在乳腺癌转移中的作用，该模型可形成具有高外显率的乳腺上皮肿瘤，并具有完整的免疫系统。我们将 PyMT 小鼠与表达 GPCR 解偶联突变体的敲入小鼠进行杂交。 p110β，以明确确定 GPCR 信号传导至 PI3Kβ 在肿瘤进展和转移中的作用，总而言之，这些研究将为我们带来重要的新见解。 PI3Kβ 的基本生物学，以及这种复杂的信号酶在乳腺癌转移中的作用。