"Post-translational modification of non-histone proteins as a mechanism of pMHC-I neo-ligand generation"

项目摘要摘要 肿瘤疫苗的发展需要更深入地了解T细胞对恶性与非肿瘤的识别 非恶性细胞。尽管T细胞免疫系统在发育过程中受到负性和 积极选择，能够识别自身蛋白的T细胞确实存在，并且对许多人来说是关键的效应器 癌症免疫疗法。目前尚不清楚的是CD8+CTL是如何激发抗肿瘤自身蛋白的 能够识别恶性细胞，但对也表达自身蛋白质的健康细胞仍然视而不见。缺欠 在这个问题上的澄清可能会阻碍针对非突变、致癌、 肿瘤自身蛋白。我们的长期目标是更深入地了解肿瘤自身抗原疫苗是如何引发的 CTL识别癌细胞，但不识别也表达该抗原的正常细胞。我们的直接客户 目标--确定迈向我们长期目标的第一个关键步骤--是确定恶性疾病是否存在差异 而非恶性细胞翻译后修饰相关的模型肿瘤自身抗原产生pMHC-I- 疫苗识别肿瘤细胞表面的新配体(S)可诱导CTL。我们假设后翻译 相关的模型肿瘤自身蛋白中赖氨酸残基的脱乙酰基在不同的恶性肿瘤之间自然不同 和非恶性细胞，导致在恶性细胞上产生pMHC-I-neo表位。指导原则 支持初步数据，我们的假设将通过两个特定的目标进行检验：1)确定肿瘤自身 肿瘤细胞中的抗原-赖氨酸脱乙酰基能够被肿瘤自身抗原疫苗识别 引发了CTL。利用质谱学，我们希望定义赖氨酸残基的差异乙酰化 相关，模型，致癌的肿瘤自身蛋白D52在恶性和非恶性细胞中表达。我们预计 D52赖氨酸乙酰化效应疫苗诱导CTL识别肿瘤细胞的实验研究 从而导致对恶性和非恶性细胞的CTL区分。使用特定的面板 从D52衍生的多肽，我们预计我们将定义D52疫苗激发的CTL pMHC-I-neo表位。2) 确定肿瘤细胞中肿瘤自身抗原赖氨酸脱乙酰基是否影响疫苗诱导 保护性肿瘤免疫。用脱乙酰酶抑制剂孵育的恶性肿瘤细胞接种于 接种D52疫苗的小鼠，超时监测肿瘤生长和肺转移终点评估， 我们希望证明，在恶性肿瘤细胞中抑制D52的自然去乙酰化会影响pMHC-I- CTL识别的表位可能导致疫苗对肿瘤的保护失败 生长和转移。影响：此概念验证项目的结果预计将产生积极影响 针对致癌肿瘤自身蛋白的更有效的下一代疫苗的开发 癌症的安全治疗或预防。同样重要的是对免疫疗法的更深层次的理解 CTL和可能影响自身免疫相关毒性的恶性和非恶性细胞歧视 被报告为免疫检查点封锁，并可能与下一代疫苗有关。

Project Summary Abstract The advancement of cancer vaccines requires a deeper understanding of T cell recognition of malignant vs non-malignant cells. Though the T cell immune repertoire is developmentally regulated by negative and positive selection, T cells capable of recognizing self-proteins do exist and are critical effectors for many cancer immunotherapies. What remains unclear is how CD8+ CTLs elicited against tumor-self proteins are capable of recognizing malignant cells yet remain blind to healthy cells that also express the self-protein. Lack of clarity on this issue may inhibit the advancement of cancer vaccines that target non-mutated, oncogenic, tumor-self proteins. Our long-term goal is a deeper understanding of how tumor-self antigen vaccine elicited CTLs recognize cancer cells but do not recognize normal cells that also express the antigen. Our immediate objective, defining the first critical step toward our long-term goal, is to determine if a difference in malignant and non-malignant cell post-translation modification of a relevant, model tumor-self antigen generates pMHC-I- neo-ligand(s) recognized on cancer cells by vaccine elicited CTLs. We hypothesize that post-translational deacetylation of lysine residues within a relevant, model tumor-self protein naturally differs between malignant and non-malignant cells resulting in the generation of pMHC-I-neo-epitopes on malignant cells. Guided by supportive preliminary data, our hypothesis will be tested with two specific aims: 1) Determine if tumor-self antigen-lysine deacetylation in malignant cells enables recognition by tumor-self antigen vaccine elicited CTLs. Using mass spectroscopy, we expect to define differential acetylation of lysine residues in the relevant, model, oncogenic tumor-self protein D52 expressed in malignant and non-malignant cells. We expect to demonstrate that D52 lysine acetylation effects D52 vaccine elicited CTL recognition of malignant cells resulting in differential CTL discrimination of malignant and non-malignant cells. Using a specific panel of peptides derived from D52, we anticipate that we will define D52 vaccine elicited CTL pMHC-I-neo-epitopes. 2) Determine if tumor-self antigen-lysine deacetylation in malignant cells impacts vaccine induced protective tumor immunity. Using malignant cells incubated with deacetylase inhibitor prior to inoculation into D52 vaccinated mice with monitoring of tumor growth overtime and endpoint assessment of lung metastases, we expect to demonstrate that inhibition of natural deacetylation of D52 in malignant cells impacts pMHC-I- epitopes that are recognized by CTLs possibly resulting in failure of the vaccine to protect against tumor growth and metastases. Impact: The results of this proof of concept project are expected to positively impact the development of more effective next-generation vaccines that target oncogenic tumor-self proteins for the safe treatment or prevention of cancer. Equally important is a deeper understanding of immunotherapy elicited CTLs and malignant, non-malignant cell discrimination that may impact auto-immune-related toxicities as has been reported for immune checkpoint blockade, and may be associated with next-generation vaccines.