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

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）：尽管乳腺癌患者对其疾病产生T细胞介导的免疫反应，但它通常会进展。在已发现的许多逃逸机制中，肿瘤细胞表达HLA I类/肿瘤抗原（TA）肽复合物的缺陷引起了人们的广泛关注，因为这些复合物参与了HLA I类限制性细胞溶解T细胞（CTL）免疫的产生。先前的研究表明，HLA I类抗原在乳腺癌细胞中经常下调。然而，这种下调是如何发生的，以及HLA- I类下调是否与HLA- I类/TA肽复合物表达水平相关，目前尚不清楚。这些信息的缺乏反映了用于评估HLA类I/TA肽复合物在肿瘤细胞（包括乳腺癌细胞）上表达的探针的有限可用性。近年来，我们已经获得了新的抗体探针，可以潜在地回答许多与乳腺癌细胞上hla - I类表达缺失相关的问题。这些探针包括能够识别hla I类/TA肽复合物的单链Fv片段，以及能够识别抗原加工和呈递机制的多种组分的众多单克隆抗体。我们将使用这些探针来定义导致hla - I类/TA肽复合物表达缺失的缺陷，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病程的关系。我们将用于检测hla - I类表达的模型抗原是HER-2/neu，这是一种在近20-30%的乳腺癌中过表达的抗原蛋白。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。具体目标是：为了研究能否通过分子模拟技术提高识别HLA-A*0201:HER2/中性肽复合物对乳腺癌细胞的亲和力、亲和性和稳定性。(2)研究APM缺陷是否下调HLA-A*0201-HER2/neu肽复合物对乳腺癌细胞的作用。(3)研究HLA-A*0201-HER2/neu肽复合物下调是否降低HLAA* 0201-HER2/neu肽特异性CTL对乳腺癌细胞的识别和细胞毒性。(4)检测乳腺癌病变中HLA-A*0201-HER2/neu肽复合物下调是否对临床病程有负面影响；(5)检测外源性药物是否能恢复APM组分和HLA-A*0201-HER2/neu肽复合物在体内的正常表达。我们期望这项研究的结果将导致对hla - I类损失对肿瘤免疫逃避的影响的更好理解。该结果可能会导致与抗原呈递相关的特定分子的鉴定，这可能是一种新的治疗靶点或疾病结果的生物标志物。