Evaluation of a therapeutic vaccination strategy with motif neoepitope peptide-pulsed autologous dendritic cells for non-small cell lung cancer patients harboring a charged HLA-B binding pocket.

项目摘要 肺癌是美国和世界上癌症相关死亡的主要原因。低效 功能性肿瘤新抗原的预测和对宿主抗肿瘤免疫应答的认识不足 免疫治疗方法的优化有限。我们最近证明，程序性细胞死亡1 （PD-1）抑制剂，其导致少数非小细胞肺癌（NSCLC）患者的持久反应， 在具有带电人类白细胞抗原（HLA）-B结合口袋的患者中具有更大的功效， 含有导致我们称为"基序新表位"的突变。基序新表位导致 九聚体（HLA结合的锚）第二位的氨基酸取代，产生 来自野生型肽的电荷，其中所得氨基酸具有与HLA-B结合相反的电荷 口袋这种取代导致增强的结合亲和力，相应的HLA-B超型证明 通过体外竞争测定。这些数据表明，基序新表位的最佳呈递是通过 相应的带电HLA超型导致体内有效的宿主抗肿瘤免疫应答。 基于树突状细胞（DC）的疫苗接种已经成为免疫治疗的潜在组成部分，这是由于其 有利的毒性特征及其在抗原特异性T细胞引发和活化中的重要作用。we have expertise 在NSCLC中评估DC原位疫苗接种策略的临床研究中。在本提案中，我们打算将联合收割机 DC作为具有推定基序新表位的功能性抗原呈递细胞（APC）作为创新疫苗接种 增强宿主全身性肿瘤特异性T细胞应答并增强当前免疫疗法的临床益处的方法 免疫疗法 我们假设1）衍生自基序新表位的肽是体内功能性新抗原， 能够诱导宿主肿瘤特异性免疫应答，和2）用基序脉冲的自体DC 新表位衍生肽，特别是在最佳条件下，将诱导基序的系统激活 新表位特异性T细胞。作为这项提议的一部分，我们正在分析从我们的 正在进行的肿瘤内注射自体DC联合PD-1抑制的I期试验， 非小细胞肺癌。收集的标本包括连续的血液和肿瘤活检以及自体DC。我们将 评估将DC暴露于衍生自基序新表位的肽是否可以诱导肿瘤特异性T细胞 在共培养实验中活化。我们将评估这些肽的结合亲和力和相应的免疫原性。 野生型肽与其各自的HLA-B超型。我们将进一步优化条件，包括添加 PD-1阻断，以通过用基序新表位衍生物脉冲的自体DC实现最佳T细胞活化 缩氨酸这些研究将极大地增强我们对基序新表位的潜在功能的理解， 诱导宿主抗肿瘤免疫应答，为今后的临床研究奠定基础 新表位脉冲的自体DC作为NSCLC的新治疗策略。

PROJECT SUMMARY Lung cancer is the leading cause of cancer related deaths in the United States and the World. Inefficient prediction of functional tumor neoantigens and insufficient understanding of host anti-tumor immune responses limit optimization of immunotherapeutic approaches. We recently demonstrated that programmed cell death 1 (PD-1) inhibitors, which lead to durable responses in a minority of non-small cell lung cancer (NSCLC) patients, have greater efficacy in patients with charged human leukocyte antigen (HLA)-B binding pockets whose tumors harbor mutation(s) leading to what we have designated as “motif neoepitopes”. Motif neoepitopes lead to an amino acid substitution in the second position of a nonamer (anchor for HLA-binding), generating a change in charge from the wild type peptide in which the resultant amino acid has a charge opposite to the HLA-B binding pocket. This substitution leads to enhanced binding affinity to the corresponding HLA-B supertype demonstrated by in vitro competition assays. These data suggest that optimal presentation of motif neoepitopes by corresponding charged HLA supertypes results in effective host anti-tumor immune responses in vivo. Dendritic cell (DC)-based vaccination has emerged as a potential component for immunotherapy due to both its favorable toxicity profile and its essential role in antigen-specific T cell priming and activation. We have expertise in clinical studies evaluating a DC in situ vaccination strategy in NSCLC. In this proposal, we intend to combine DCs as functional antigen presenting cells (APCs) with putative motif neoepitopes as an innovative vaccination approach to enhance host systemic tumor-specific T cell responses and potentiate clinical benefits of current immunotherapies. We hypothesize that 1) peptides derived from motif neoepitopes are functional neoantigens in vivo that are capable of inducing host tumor-specific immune responses, and 2) autologous DCs pulsed with motif neoepitope-derived peptides, particularly at optimal conditions, will induce systemic activation of motif neoepitope-specific T cells. As part of this proposal, we are analyzing multiple biospecimens collected from our ongoing phase I trial of intratumoral injection of autologous DCs combined with PD-1 inhibition in advanced NSCLC. Collected specimens include serial blood and tumor biopsies as well as autologous DCs. We will evaluate whether exposing DCs to peptides derived from motif neoepitopes can induce tumor-specific T cell activation in co-culture experiments. We will assess the binding affinity of these peptides and the corresponding wild type peptides to their respective HLA-B supertype. We will further optimize conditions, including addition of PD-1 blockade, to achieve optimal T cell activation by autologous DCs pulsed with motif neoepitope-derived peptides. These studies will greatly enhance our understanding of the potential function of motif neoepitopes in inducing host anti-tumor immune responses, and lay the foundation for future clinical investigations of motif neoepitope-pulsed autologous DCs as a novel treatment strategy for NSCLC.