Targeting Chronic ER Stress in T Cells to Improve Cancer Immunotherapy

项目摘要 肉瘤是一种免疫原性肿瘤类型，充满肿瘤抗原，经历CD 8肿瘤浸润 淋巴细胞（TIL）。令人惊讶的是，靶向程序性细胞死亡蛋白1（a-PD-1）的检查点疗法， 重振CD 8 TIL在肉瘤中基本上无效，并且尚未获得FDA批准。CD 8 TILs经验 应激，但尚未在癌症患者的CD 8 TIL中广泛研究应激反应。在急性压力下， 内质网（ER）应激传感器蛋白激酶R（PKR）样ER激酶（PERK）保护细胞。下 在慢性压力下，PERK激活诱导细胞死亡的促凋亡反应。我们先前表明 PERK对肿瘤中的CD 8 T细胞有害。我们现在揭示了强有力的初步数据，表明 慢性PERK轴由激活转录因子4（ATF 4）和ER氧化还原酶1（ERO 1a）控制 在小鼠和人肉瘤中形成CD 8 TIL命运并损害对α-PD-1疗法的应答。我们的数据是 考虑到PERK通过减弱翻译在急性应激下保护细胞的作用，这是有趣的。的确， 我们发现，肿瘤微环境是一种急性应激形式，通过以下途径抑制CD 8 T细胞的翻译： 福利。然而，在体内存在肿瘤抗原的情况下，PERK应答的慢性臂似乎 决定PD-1+ CD 8 TIL的命运。该提案将正式测试慢性靶点ATF 4和ERO 1a驱动激活 CD 8 TILs的急性PERK反应和代谢衰竭限制了α-PD-1治疗的疗效， 在肉瘤微环境应激下保护CD 8 TILs。为了实现我们的目标，我们开发了独特的 遗传小鼠模型来分析应激的慢性和急性阶段的T细胞特异性贡献 肉瘤中a-PD-1疗法对形状的反应功效。在目标1中，我们将使用LckcreRosa 26-ATF 4loxtg小鼠 用T细胞特异性过表达来自肉瘤患者的人ATF 4和CD 8 TILs，以确定 ATF 4在CD 8 TIL中驱动活化和耗竭的贡献以及对a-PD-1治疗的形状反应 肉瘤这些结果有望重新构建和推进我们对肉瘤中T细胞耗竭的理解。 在目标2中，我们创建了独特的ERO 1a-/-小鼠，以正式定义ERO 1a如何影响CD 8 TIL代谢 我们将使用来自肉瘤患者的CD 8 TILs来研究对α-PD-1治疗的耗竭和应答， ERO 1a对人TIL耗竭的贡献。这些结果有望产生一个强大的分子靶点 这对于提高α-PD-1疗法在癌症患者中的疗效具有巨大的潜力。在目标3中，我们将使用 我们的LckcrePERKf/f小鼠和Eif 2aS 51 A突变小鼠，以阐明CD 8+细胞中急性应激反应的需要。 TILs。该结果有望塑造围绕ER应激反应的药物开发方向 癌症免疫疗法成功完成这项提案将确定激进的新的慢性ER压力 这些靶点破坏了肉瘤患者免疫治疗的广泛成功，并建立了一种新的 这一范例为所有实体瘤癌症患者的药物开发提供了信息。

PROJECT SUMMARY Sarcomas are an immunogenic tumor type replete with tumor antigen experienced CD8 tumor infiltrating lymphocytes (TILs). Surprisingly, checkpoint therapy that targets programmed cell death protein 1 (a-PD-1) to reinvigorate CD8 TILs is largely ineffective in sarcomas and has not gained FDA approval. CD8 TILs experience stress, but the stress response has not been widely studied in CD8 TILs of cancer patients. Under acute stress, endoplasmic reticulum (ER) stress sensor protein kinase R (PKR)-like ER kinase (PERK) protects cells. Under chronic stress, PERK activates a pro-apoptotic response that induces cell death. We previously demonstrated that PERK is detrimental to CD8 T cells in tumors. We now reveal robust preliminary data that indicate that the chronic PERK axis governed by activating transcription factor 4 (ATF4) and ER oxidoreductase 1 (ERO1a) shapes CD8 TIL fate in mouse and human sarcomas and impairs response to a-PD-1 therapy. Our data are intriguing given the role of PERK to protect cells under acute stress through attenuation of translation. Indeed, we found that the tumor microenvironment is a form of acute stress that inhibits translation in CD8 T cells through PERK. However, in vivo in the presence of tumor antigen, the chronic arm of the PERK response appears to dictate PD-1+ CD8 TIL fate. This proposal will formally test that chronic targets ATF4 and ERO1a drive activation and metabolic exhaustion in CD8 TILs that limit the efficacy of a-PD-1 therapy, while the acute PERK response protects CD8 TILs under sarcoma microenvironment stress. To accomplish our aims we have developed unique genetic mouse models to analyze the T cell-specific contributions of the chronic and acute phases of the stress response to shape efficacy of a-PD-1 therapy in sarcomas. In Aim 1, we will use LckcreRosa26-ATF4loxtg mice with T cell-specific overexpression of human ATF4 and CD8 TILs from sarcoma patients to determine the contribution of ATF4 to drive activation and exhaustion in CD8 TILs and shape response to a-PD-1 therapy in sarcomas. The results are expected to reframe and advance our understanding of T cell exhaustion in sarcomas. In Aim 2 we have created unique ERO1a-/- mice to formally define how ERO1a affects CD8 TIL metabolic exhaustion and response to a-PD-1 therapy and we will use CD8 TILs from sarcoma patients to study the contribution of ERO1a to human TIL exhaustion. The results are expected to produce a robust molecular target that holds fantastic potential to improve the efficacy of a-PD-1 therapy in cancer patients. In Aim 3 we will use our LckcrePERKf/f mice and Eif2aS51A mutant mice to elucidate requirements of the acute stress response in CD8 TILs. The results are expected to shape the direction of drug development surrounding the ER stress response in cancer immunotherapy. Successful completion of this proposal will identify radical new chronic ER stress targets that undermine the widespread success of immunotherapy in sarcoma patients and establish a new paradigm that informs drug development for all solid tumor cancer patients.