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

项目摘要 癌症疫苗的发展需要更深入地了解T细胞对恶性肿瘤的识别， 非恶性细胞。尽管T细胞免疫库在发育上受到负调控， 积极的选择，T细胞能够识别自身蛋白质确实存在，是许多关键的效应 癌症免疫疗法目前尚不清楚的是，CD 8 + CTL是如何诱导抗肿瘤自身蛋白的， 能够识别恶性细胞，但对同样表达自身蛋白质的健康细胞保持盲态。缺乏 在这个问题上的明确可能会抑制靶向非突变的，致癌的， 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 CTL识别癌细胞，但不识别也表达抗原的正常细胞。我们眼前的 我们的目标是确定实现我们长期目标的第一个关键步骤，即确定恶性肿瘤的差异是否存在。 并且相关的模型肿瘤自身抗原的非恶性细胞翻译后修饰产生pMHC-I- 通过疫苗在癌细胞上识别的新配体引发CTL。我们假设翻译后 在相关的模型肿瘤自身蛋白中赖氨酸残基的脱乙酰化在恶性肿瘤和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-新表位。指导 支持的初步数据，我们的假设将进行测试，有两个具体的目标：1）确定是否肿瘤本身 恶性细胞中的抗原-赖氨酸脱乙酰化使得能够被肿瘤-自身抗原疫苗识别 引发CTL。使用质谱，我们期望定义在蛋白质中赖氨酸残基的差异乙酰化。 在恶性和非恶性细胞中表达的相关模型致癌肿瘤自身蛋白D52。我们预计 为了证明D52赖氨酸乙酰化效应，D52疫苗引起恶性细胞的CTL识别 导致恶性和非恶性细胞的差异性CTL区分。使用特定的面板， D52疫苗诱导的CTL pMHC-I-neo-表位。（二） 确定恶性细胞中的肿瘤自身抗原-赖氨酸脱乙酰化是否影响疫苗诱导 保护性肿瘤免疫使用在接种到大肠杆菌中之前与脱乙酰酶抑制剂一起孵育的恶性细胞， D52接种的小鼠，随时间监测肿瘤生长和肺转移的终点评估， 我们期望证明在恶性细胞中抑制D52的天然脱乙酰化影响pMHC-I-1， CTL识别的表位可能导致疫苗不能保护免受肿瘤 生长和转移。影响：该概念验证项目的结果预计将产生积极影响 开发更有效的下一代疫苗，靶向致癌肿瘤自身蛋白， 安全治疗或预防癌症。同样重要的是， CTL和恶性、非恶性细胞的区分可能影响自身免疫相关毒性， 据报道，免疫检查点封锁，并可能与下一代疫苗。

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.