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：
8687302
负责人：
Kenan Christopher GARCIA
金额：
$ 30.94万
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/8687302
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 Ligands Ligation Link Macrophage Activation Malignant Neoplasms Microbe Modeling Molecular Molecular Target Monoclonal Antibodies Mus Neoplasm Transplantation 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 SIRPα, an inhibitory receptor expressed on macrophages. Ligation of SIRPα by CD47 blocks macrophages from phagocytosing the tumor cells. The CD47/SIRPα axis represents a toggle switch that can be blocked or stimulated for different therapeutic goals. Blocking binding of CD47 to SIRPα promotes phagocytosis of cancer cells. Conversely, the CD47/SIRPα 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 SIRPα/CD47 system offers an exciting new axis for both anti-tumor and transplant therapy. However, effective utilization of the soluble ectodomains of either SIRPv or CD47 as agonists, or antagonists is limited by the low affinity of the wild-type CD47/SIRPα interaction. We wish to execute a structure-based engineering approach to creating high-affinity SIRPα 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/SIRPα axis. For Aim #1, we have engineered high-affinity SIRPα monomers, that prevent the interaction between endogenous CD47 and SIRPα, 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 SIRPα 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 SIRPα 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”。巨噬细胞在其目标细胞上发出“别吃我”的信号，当它们通过血窦时，巨噬细胞会检查迁移的造血干细胞。它表达促吞噬细胞的“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“不要吃我”信号。 SIRPα 的配体，巨噬细胞上表达的抑制性受体 CD47 连接 SIRPα 可阻止巨噬细胞吞噬肿瘤细胞。轴代表可以针对不同治疗目标阻断或刺激的切换开关。阻断 CD47 与 SIRPα 的结合可促进癌细胞的离线吞噬作用，CD47/SIRPα 相互作用是造血细胞移植 (HCT) 中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性相关，不幸的是，骨髓 HSC 表达低水平的 CD47，这是其相对的原因。因此，根据临床情况，SIRPα/CD47 系统为抗肿瘤和移植治疗提供了令人兴奋的新轴。然而，有效利用 SIRPv 或 CD47 的可溶性胞外域作为激动剂或拮抗剂。受到野生型 CD47/SIRPα 相互作用的低亲和力的限制，我们希望执行基于结构的工程方法来创建高亲和力的 SIRPα 和 CD47。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。对于目标#1，我们设计了高亲和力的 SIRPα 单体，可以防止内源性 CD47 和 SIRPα 之间的相互作用，并显着地阻止内源性 CD47 和 SIRPα 之间的相互作用。与临床上建立的治疗性单克隆抗体协同作用，刺激体内肿瘤细胞的吞噬作用，对巨噬细胞进行“1-2”靶向敏化，然后用抗肿瘤单克隆抗体进行细胞溶解，这是一种全新的策略。设计高亲和力 CD47 变体，激活 SIRPα 抑制信号并减少巨噬细胞活化，从而增强 HSC 植入。最后，在目标 3 中，我们希望重建并分子表征由 CD47 和 SIRPα 与假定的替代配体（包括血小板反应蛋白和整合素）组成的细胞表面“别吃我”复合物，以便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会产生结果。应用于多种人类癌症和移植治疗的新型生物治疗药物。