Engineering of macrophage phagocytosis for cancer and stem cell immunotherapy

用于癌症和干细胞免疫治疗的巨噬细胞吞噬工程

基本信息

批准号：
8840913
负责人：
Kenan Christopher GARCIA
金额：
$ 33.46万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-05-01 至 2019-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8840913
关键词：
Accounting Adjuvant Affinity Agonist Alleles Antibodies Binding Biochemical Biological Response Modifier Therapy Biology Biomedical Engineering Blocking Antibodies Bone Marrow Bone Marrow Stem Cell Bone Marrow Transplantation CD47 gene Cancerous Cell Surface Receptors Cell surface Cells Cellular Assay Cellular Structures Cetuximab Clinical Complex Cytolysis Data Diagnostic Discontinuous Capillary Donor person Eating Engineering Engraftment Ensure Excision Goals Health Hematopoietic Neoplasms Hematopoietic stem cells Human Immune Immune Targeting Immune system Immunotherapeutic agent Immunotherapy In Vitro Integrins Intervention Knowledge Left Ligands Ligation Link Macrophage Activation Malignant Neoplasms Membrane Microbe Modeling Molecular Molecular Target Monoclonal Antibodies Mus Neoplasm Transplantation PTPNS1 gene Phagocytes Phagocytosis Process Protein Engineering Relative (related person)Reporting Signal Transduction Solid Neoplasm Stem cell transplant Stem cells Stress Structure System Testing Therapeutic Therapeutic Agents Therapeutic Monoclonal Antibodies Thrombospondin 1 Tissues Transplantation Transplantation Immunology Trastuzumab Treatment Efficacy Up-Regulation Variant Wound Healing base biophysical properties calreticulin cancer cell cancer stem cell cancer therapy hematopoietic cell transplantation human stem cells in vivo macrophage monomer mouse model neoplastic neoplastic cell novel novel strategies novel therapeutics prevent programs receptor reconstitution rituximab stem structural biology success tissue repair tumor tumor immunology

项目摘要

DESCRIPTION (provided by applicant): Macrophages are phagocytic cells that recognize and 'eat' foreign cellular microbes, as well as dying cells and aberrant cells such as cancers. They display a variety of receptors by which they recognize 'eat me' and 'don't eat me' signals on their target cells. Macrophages inspect migrating hematopoietic stem cells (HSC) as they pass through the sinusoids. Macrophages also inspect cancer cells, which express pro-phagocytic 'eat me' signals to ensure that aberrant cells are ingested in a process termed programmed cell removal. However, successful cancer cells evade programmed cell removal by expressing CD47, a dominant 'don't eat me' signal that is a ligand for SIRP¿, an inhibitory receptor expressed on macrophages. Ligation of SIRP¿ by CD47 blocks macrophages from phagocytosing the tumor cells. The CD47/SIRP¿ axis represents a toggle switch that can be blocked or stimulated for different therapeutic goals. Blocking binding of CD47 to SIRP¿ promotes phagocytosis of cancer cells. Conversely, the CD47/SIRP¿ interaction is a critical determinant of engraftment success in hematopoietic cell transplantation (HCT): CD47 expression levels on HSC correlate with their relative engraftability. Unfortunately, bone marrow HSC express low levels of CD47, accounting for their relative inefficiency in transplantation. Thus, depending on the clinical scenario, the SIRP¿/CD47 system offers an exciting new axis for both anti-tumor and transplant therapy. However, effective utilization of the soluble ectodomains of either SIRP¿ or CD47 as agonists, or antagonists is limited by the low affinity of the wild-type CD47/SIRP¿ interaction. We wish to execute a structure-based engineering approach to creating high-affinity SIRP¿ and CD47 ectodomains as therapeutics for cancer and HCT. We propose to combine the expertise of the Garcia lab in structural biology, protein engineering and immune intervention, with the strengths of the Weissman and Shizuru labs in in vivo cancer, and hematopoietic cell transplantation biology, to target the CD47/SIRP¿ axis. For Aim #1, we have engineered high-affinity SIRP¿ monomers, that prevent the interaction between endogenous CD47 and SIRP¿, and dramatically synergize with clinically-established therapeutic monoclonal antibodies in stimulating phagocytosis of tumor cells in vivo. This "1-2" punch of target sensitization to macrophages followed by cytolysis by anti-tumor mAb is a completely novel strategy. For Aim #2, we are engineering high-affinity CD47 variants that activate SIRP¿ inhibitory signaling and decrease macrophage activation, thus enhancing HSC engraftment. Finally, in Aim #3 we wish to reconstitute and molecularly characterize the cell surface 'don't eat me' complex composed of CD47 and SIRP¿ with putative alternative ligands including thrombospondin and integrins in order to fully understand the therapeutic potential of this system for modulating macrophage phagocytosis. We anticipate these studies will yield novel classes of biotherapeutics with applications in many types of human cancers, and for transplant therapy.

描述（由申请人提供）：巨噬细胞是识别并“吃掉”外来细胞微生物以及垂死细胞和异常细胞（例如癌症）的吞噬细胞，它们表现出多种受体，通过这些受体识别“吃掉我”和“不吃我”。他们身上有“别吃我”的信号巨噬细胞在穿过血窦时检查迁移的造血干细胞（HSC），巨噬细胞还检查癌细胞，癌细胞表达促吞噬细胞“吃我”信号，以确保异常细胞在称为程序性细胞去除的过程中被摄入。然而，成功的癌细胞通过表达 CD47 来逃避程序性细胞去除，CD47 是一种显性的“别吃我”信号，是 SIRP 的配体。，巨噬细胞上表达的抑制性受体。 CD47 阻断巨噬细胞吞噬肿瘤细胞。轴代表一个切换开关，可以针对不同的治疗目标阻断或刺激阻断 CD47 与 SIRP 的结合。促进癌细胞的离线吞噬作用，CD47/SIRP¿相互作用是造血细胞移植 (HCT) 植入成功的关键决定因素：HSC 上的 CD47 表达水平与其相对植入能力相关，不幸的是，骨髓 HSC 表达低水平的 CD47，这导致其移植效率相对较低。临床场景，SIRP¿ /CD47 系统为抗肿瘤和移植治疗提供了一个令人兴奋的新轴，然而，有效利用任一 SIRP 的可溶性胞外域。或 CD47 作为激动剂或拮抗剂受限于野生型 CD47/SIRP 的低亲和力。我们希望执行基于结构的工程方法来创建高亲和力 SIRP¿我们建议将 Garcia 实验室在结构生物学、蛋白质工程和免疫干预方面的专业知识与 Weissman 和 Shizuru 实验室在体内癌症和造血细胞移植生物学方面的优势结合起来。以 CD47/SIRP 为目标??对于目标 #1，我们设计了高亲和力 SIRP¿单体，阻止内源性 CD47 和 SIRP 之间的相互作用¿ ，并与临床上建立的治疗性单克隆抗体显着协同作用，刺激体内肿瘤细胞的吞噬作用，这种对巨噬细胞的靶标敏化然后用抗肿瘤单克隆抗体进行细胞溶解是一种全新的策略。，我们正在设计激活 SIRP 的高亲和力 CD47 变体¿最后，在目标 3 中，我们希望重建由 CD47 和 SIRP 组成的细胞表面“别吃我”复合物并对其进行分子表征。与假定的替代配体（包括血小板反应蛋白和整合素）一起，以充分了解该系统调节巨噬细胞吞噬作用的治疗潜力，我们预计这些研究将产生新型生物治疗药物，可应用于多种类型的人类癌症和移植治疗。