HLA class l complex expression in breast cancer immunity

乳腺癌免疫中 HLA I 类复合物的表达

• 批准号: 6906817
• 负责人: Keith L. Knutson
• 金额: $ 24.62万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-23 至 2010-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6906817
• 关键词: MHC class I antigen; NOD mouse; SCID mouse; SDS polyacrylamide gel electrophoresis; affinity chromatography; antigen presentation; breast neoplasms; clinical research; cytotoxic T lymphocyte; enzyme linked immunosorbent assay; flow cytometry; gene expression; human tissue; immunocytochemistry; molecular oncology; neoplasm /cancer genetics; neoplasm /cancer immunology; pathologic process; polymerase chain reaction; protooncogene; MHC class I antigen; NOD mouse; SCID mouse; SDS polyacrylamide gel electrophoresis; affinity chromatography; antigen presentation; breast neoplasms; clinical research; cytotoxic T lymphocyte; enzyme linked immunosorbent assay; flow cytometry; gene expression; human tissue; immunocytochemistry; molecular oncology; neoplasm /cancer genetics; neoplasm /cancer immunology; pathologic process; polymerase chain reaction; protooncogene

DESCRIPTION (provided by applicant): Although patients with breast carcinoma mount a T cell-mediated immune response to their disease it usually progresses. Among the many escape mechanisms identified, defects in HLA class I/tumor antigen(TA) peptide complex expression by tumor cells have attracted much attention since these complexes are involved in the generation of HLA class I restricted cytolytic T cell (CTL) immunity. Previous studies have shown that HLA class I antigens are frequently down-regulated in breast cancer cells. However, it remains unknown as to how this down-modulation occurs and whether HLA-class I down-modulation correlates with the level of HLA class I/TA peptide complex expression. The lack of this information reflects the limited availability of probes to evaluate expression of HLA class I/TA peptide complexes on tumor cells, including breast carcinoma cells. In recent years, we have acquired new antibody probes that could potentially answer many questions related to loss of HLA-class I expression on breast cancer cells. These probes include single chain Fv fragments that are able to recognize HLA-class I/TA peptide complexes as well as numerous monoclonal antibodies that recognize multiple components of the antigen processing and presentation machinery. We will use these probes to define the defects that lead to the loss of HLA-class I/TA peptide complex expression, how these defects that lead to tumor immune evasion, and the relationship of this evasion to the clinical course of the disease. The model antigen we will use to examine HLA-class I expression is HER-2/neu, an antigenic protein overexpressed on nearly 20-30% of breast cancers. We will then examine in xenograft models whether upregulation of the complexes in vivo can improve sensitivity to T cell killing. The specific aims are: To examine whether the affinity, avidity, and stability of scFVs, that recognize HLA-A*0201:HER2/neupeptide complexes on breast cancer cells, can be improved with molecular modeling techniques (2) To examine whether defects in the APM downregulate HLA-A*0201-HER2/neu peptide complexes on breast carcinoma cells, (3) To examine whether HLA-A* 0201-HER2/neu peptide complex downregulation reduces breast cancer cell recognition and cytotoxicity by HLAA* 0201-HER2/neu peptide-specific CTL, (4) To examine whether HLA-A*0201-HER2/neu peptide complex downregulation in breast cancer lesions has a negative impact on the clinical course of the disease, and (5) To examine whether exogenous agents can restore normal expression of APM components and HLA-A*0201-HER2/neu peptide complexes in vivo. We expect that the results from this study will lead to an improved understanding of the impact of HLA-class I loss on tumor immune evasion. The results will likely lead to the identification of specific molecule associated with antigen presentation that could be either a novel therapeutic target or biomarker of disease outcome.

描述（由申请人提供）：尽管患有乳腺癌的患者对T细胞介导的对其疾病的免疫反应持续了，但它通常会进展。在确定的许多逃生机制中，肿瘤细胞中HLA I/肿瘤抗原（TA）肽复合物表达的缺陷引起了很多关注，因为这些复合物与HLA I类限制的细胞溶解T细胞（CTL）免疫有关。先前的研究表明，HLA I类抗原经常在乳腺癌细胞中下调。但是，对于这种下调的发生方式以及HLA级I下调是否与HLA I/TA类肽复合物表达的水平相关，仍然未知。缺乏这些信息反映了探针可用性有限，以评估包括乳腺癌细胞在内的肿瘤细胞上HLA I/TA肽复合物的表达。近年来，我们获得了新的抗体探针，这些抗体探针可能会回答许多与HLA级I在乳腺癌细胞上的表达丧失有关的问题。这些探针包括能够识别HLA级I/TA肽复合物以及众多识别抗原加工和表现机制多个组分的单克隆抗体的单链FV片段。我们将使用这些探针来定义导致HLA级I/TA肽复合物表达丧失的缺陷，这些缺陷如何导致肿瘤免疫逃避，以及这种逃避与疾病临床过程的关系。我们将用来检查HLA级I表达的模型抗原是HER-2/NEU，这是一种在近20％的乳腺癌上过表达的抗原蛋白。然后，我们将在异种移植模型中检查体内复合物的上调是否可以提高对T细胞杀伤的敏感性。具体目的是：检查SCFV的亲和力，亲和力和稳定性是否可以通过分子建模技术（2）来改善乳腺癌细胞上HLA-A*0201：HER2/Ne-Ne-Dapeptide复合物，以检查APM中的APM中的缺陷是否下调HLA-A*0201- A*0201- her2/neu percypers（3），在乳腺癌中均为3.0201-her2/neu peptermens（3），（3）上的胸肌（3）上的胸肌（3），（3）上的胸肌（3），（3）上的（3）上的（3）上的（3）上的（3）上的（3） HLA-A* 0201-HER2/NEU肽复合物下调下调HLAA* 0201-HER2/NEU肽特异性CTL降低了乳腺癌细胞的识别和细胞毒性，（4）检查HLA-A* 0201-HER2/NEU肽在乳腺癌中是否疾病是否影响了乳腺癌的疾病，并且是否效果是否有癌症的影响。外源性剂可以恢复APM成分的正常表达，而HLA-A*0201-HER2/NEU肽复合物在体内。我们预计这项研究的结果将导致人们对HLA级I损失对肿瘤免疫逃避的影响有了深刻的了解。结果可能会导致鉴定与抗原表现相关的特定分子，这可能是新型的治疗靶标或疾病结局的生物标志物。