Targeting Chronic ER Stress in T Cells to Improve Cancer Immunotherapy

项目总结 肉瘤是一种充满肿瘤抗原的免疫原性肿瘤类型，经历了CD8肿瘤的侵袭 淋巴细胞(TIL)。令人惊讶的是，针对程序化细胞死亡蛋白1(a-PD-1)的检查点疗法 重振CD8 TIL对肉瘤很大程度上无效，尚未获得FDA的批准。CD8 TIL体验 应激，但在癌症患者的CD8 TIL中，应激反应尚未被广泛研究。在严重的压力下， 内质网(ER)应激感受器蛋白激酶R(PKR)样ER激酶(PERK)保护细胞。在……下面 慢性应激时，PERK会激活促细胞凋亡的反应，导致细胞死亡。我们之前演示过 这种刺激对肿瘤中的CD8 T细胞是有害的。我们现在公布的初步数据显示， 激活转录因子4(ATF4)和内质网氧化还原酶1(ERO1a)控制的慢性Perk轴 在小鼠和人类肉瘤中塑造CD8 T细胞的命运，并损害对a-PD-1治疗的反应。我们的数据是 耐人寻味的是，PERK通过减弱翻译来保护处于急性应激状态下的细胞。的确， 我们发现，肿瘤微环境是一种急性应激，通过抑制CD8T细胞的翻译 额外津贴。然而，在体内存在肿瘤抗原的情况下，慢性手臂的PERK反应似乎 主宰PD-1+CD8直到命运。这项提议将正式测试慢性靶向ATF4和ERO1a驱动激活 和CD8 TIL中限制a-PD-1治疗疗效的代谢衰竭，而急性PERK反应 在肉瘤微环境应激下保护CD8 TIL。为了实现我们的目标，我们开发了独特的 小鼠遗传模型分析慢性和急性期应激的T细胞特异性贡献 A-pd-1治疗肉瘤对形态疗效的反应。在目标1中，我们将使用LockcreRosa26-ATF4loxtg小鼠 用肉瘤患者T细胞特异性高表达人ATF4和CD8 TIL来确定 ATF4在CD8细胞活化和耗竭中的作用及对α-PD-1治疗的形状反应 肉瘤。这一结果有望重塑和推进我们对肉瘤中T细胞耗竭的理解。 在目标2中，我们创造了独特的ERO1a-/-小鼠，以正式定义ERO1a如何影响CD8 TIL代谢 疲劳和对α-PD-1治疗的反应，我们将使用肉瘤患者的CD8 TIL来研究 ERO1a对人类直到力竭的贡献。预计结果将产生一个强大的分子靶标。 这具有极大的潜力来提高a-PD-1疗法在癌症患者中的疗效。在《目标3》中，我们将使用 我们的LockcrePERKf/f小鼠和Eif2aS51a突变小鼠阐明了CD8急性应激反应的要求 TILS。这一结果有望塑造围绕内质网应激反应的药物开发方向 在癌症免疫治疗方面。成功完成这项建议将识别激进的新的慢性内质网压力 破坏免疫治疗在肉瘤患者中广泛成功并建立新的 为所有实体肿瘤癌症患者提供药物开发的范例。

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.