Stress Induction of Glucose Regulated Protein GRP78/BiP

葡萄糖调节蛋白 GRP78/BiP 的应激诱导

• 批准号: 9978717
• 负责人: AMY S LEE
• 金额: $ 57.05万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 1980
• 资助国家: 美国
• 起止时间: 1980-04-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9978717
• 关键词: Address; Antibodies; Apoptotic; Binding; Binding Proteins; Biochemical; Biological Process; Breast Cancer cell line; CD44 gene; Cell surface; Cells; Cessation of life; Clinical; Clinical Trials; Complex; Cytotoxic Chemotherapy; Detection; Disseminated Malignant Neoplasm; Endoplasmic Reticulum; Exhibits; GBF1 gene; GRP78 gene; Golgi Apparatus; Grant; Hormonal; Human; In Vitro; KDEL Motif; Malignant Neoplasms; Mediating; Mediator of activation protein; Modeling; Molecular; Molecular Chaperones; Monoclonal Antibodies; Monoclonal Antibody Therapy; Mutation; Neoplasm Circulating Cells; Neoplasm Metastasis; Oncogenic; Organ; Pathologic; Pathway interactions; Patients; Peptides; Pharmaceutical Preparations; Phase; Positron-Emission Tomography; Property; Protein Tyrosine Kinase; Proteins; Proto-Oncogenes; Regulation; Resistance; Resolution; Role; Route; SRC gene; Signal Pathway; Signal Transduction; Specificity; Stress; Surface; System; Testing; Toxin; Transforming Growth Factor beta; Up-Regulation; Xenograft procedure; anti-cancer; base; cancer cell; cancer stem cell; cell motility; chemotherapy; confocal imaging; endoplasmic reticulum stress; glucose-regulated proteins; imaging approach; in vivo; in vivo evaluation; neoplastic cell; novel; overexpression; protein function; proteotoxicity; receptor; response; single molecule; stemness; targeted treatment; therapy resistant; tumor; tumor growth; tumorigenesis

Project Summary/Abstract The discovery that GRP78, traditionally regarded as a typical endoplasmic reticulum (ER) lumenal protein, can relocalize to the cell surface under pathological stress such as cancer, changes the paradigm on how this protein exerts its pro-proliferative and anti-apoptotic functions in cancer. Cell surface GRP78 (csGRP78) is emerging as a novel co-receptor controlling cell signaling, proliferation, survival, metastasis and renewal. Its mode of function does not require ATP, thus distinct from its ER foldase activity. Furthermore, since csGRP78 is preferentially expressed in cancer cells but not in normal organs, csGRP78 represents a new target as well as mediator for cancer-specific therapy. Agents including drug-conjugated peptides, toxins and antibodies have been developed targeting csGRP78 and have shown robust activities in blocking its oncogenic functions, suppressing tumor growth in both xenografts and spontaneous tumor models, and synergizing with standard chemotherapy. Of note, monoclonal antibody targeting csGRP78 has completed Phase I/IIa clinical trials with positive response. Despite these exciting advances, how ER stress induces csGRP78 expression and how csGRP78 exerts its biological function are largely unknown. During the past grant period, we discovered that inhibition of the ER stress-inducible proto-oncogene tyrosine kinase protein SRC (c-SRC) potently blocks cell surface expression of GRP78 and other ER lumenal proteins containing the KDEL ER retention motif in a wide variety of cancer cells. We have identified novel binding partners of GRP78 on the cell surface including CD44 and CD109 with established functions in cell motility, invasion, signaling, proliferation and survival. Based on these exciting findings, we propose the following two integrated aims. Aim 1 will investigate how ER stress causes relocalization of GRP78 from the ER to the cell surface. We will test a new concept that a major pathway whereby cancer cells export ER chaperones bearing the KDEL motif to the cell surface is triggered by SRC activation and its subsequent activation of ASAP1, GBF1 and Arf1 leading to blockage of Golgi to ER retrograde. We will also investigate additional SRC downstream effectors and SRC/Golgi-independent routes for csGRP78 expression in exceptional cases. Aim 2 will address how csGRP78 regulates its cell surface partner proteins and their signaling pathways. We will study their physical and functional interactions through biochemical, mutational, as well as confocal and single molecule super-resolution imaging approaches. We will focus on CD44 with established roles in cancer invasion and stemness and perform in vitro and in vivo tests utilizing established human breast cancer cell lines with differential metastatic potential, as well as novel ex vivo culture of patient-derived circulating tumor cells exhibiting metastatic and cancer stem cell properties. We will also study novel mechanisms of csGRP78, through interaction with CD109, in regulating TGF-β-mediated tumor suppressing as well as tumor promoting functions. Collectively, these studies will reveal novel mechanisms for SRC and csGRP78 in tumorigenesis with wide clinical implications.

项目总结/摘要 GRP 78是一种典型的内质网蛋白， 在病理压力下，如癌症，可以重新定位到细胞表面，改变了这一模式， 蛋白在癌症中发挥其促增殖和抗凋亡功能。细胞表面GRP 78（csGRP 78）是 作为控制细胞信号传导、增殖、存活、转移和更新的新型共受体出现。其 其功能模式不需要ATP，因此与其ER折叠酶活性不同。此外，由于csGRP 78是 优先在癌细胞中表达，而不是在正常器官中表达，csGRP 78代表了一个新的靶点， 用于癌症特异性治疗的介体。包括药物缀合的肽、毒素和抗体的试剂具有 被开发为靶向csGRP 78并在阻断其致癌功能方面显示出强大的活性， 抑制异种移植物和自发性肿瘤模型中的肿瘤生长，并与标准的 化疗值得注意的是，靶向csGRP 78的单克隆抗体已完成I/IIa期临床试验， 积极回应。尽管有这些令人兴奋的进展，但ER应激如何诱导csGRP 78表达以及如何诱导csGRP 78表达的研究仍处于探索阶段。 csGRP 78发挥其生物学功能在很大程度上是未知的。在过去的赠款期间，我们发现， 抑制ER应激诱导的原癌基因酪氨酸激酶蛋白SRC（c-SRC）有效地阻断细胞增殖， GRP 78和其他含有KDEL ER保留基序的ER内腔蛋白的表面表达在广泛的 各种癌细胞。我们已经鉴定了细胞表面GRP 78的新型结合伴侣，包括CD 44 和CD 109，其在细胞运动、侵袭、信号传导、增殖和存活中具有确定的功能。基于 鉴于这些令人振奋的发现，我们提出以下两个综合目标。目的1将研究内质网应激 导致GRP 78从ER重新定位到细胞表面。我们将测试一个新的概念， 癌细胞将携带KDEL基序的ER分子伴侣输出到细胞表面的途径由以下触发： SRC激活及其随后激活ASAP 1、GBF 1和Arf 1，导致高尔基体对ER的阻断 逆行我们还将研究其他SRC下游效应子和SRC/Golgi独立途径， csGRP 78在例外情况下表达。目的2将解决csGRP 78如何调节其细胞表面伴侣 蛋白质及其信号通路。我们将研究它们的物理和功能相互作用， 生物化学、突变以及共聚焦和单分子超分辨率成像方法。我们将 专注于CD 44在癌症侵袭和干性中的既定作用，并进行体外和体内测试 利用已建立的具有差异转移潜能的人乳腺癌细胞系以及新的离体培养物， 表现出转移性和癌症干细胞特性的患者来源的循环肿瘤细胞。我们还将学习小说 csGRP 78通过与CD 109相互作用调节TGF-β介导的肿瘤抑制作用， 以及促肿瘤作用。总的来说，这些研究将揭示SRC的新机制， csGRP 78在肿瘤发生中具有广泛的临床意义。