Engineering immunotherapeutic probiotics to mitigate irAE

项目摘要/摘要 近年来，随着单抗的使用，癌症免疫治疗领域出现了复兴。 针对免疫检查点的抗体激活抗癌免疫反应展示了无与伦比的 临床上的成功。其中几种疗法现在已获得FDA的批准，并成为常规治疗的一部分 治疗几种恶性肿瘤的药物。尽管免疫治疗方案总体上取得了成功，但现有的 模式呈现当前研究努力试图克服的复杂性：(1)系统性交付 检查点阻断单抗导致多种和不可预测的免疫相关不良事件 (IRAE)，(2)增强来自内源性抗肿瘤谱系的反应通常依赖于前- 启动的抗肿瘤T细胞，在高度免疫抑制肿瘤或低突变肿瘤的情况下 负担可能是极其罕见的，以及(3)尝试结合免疫疗法来增加T细胞反应 证明靶上和肿瘤外的毒性增加。因此，为了规避毒性和免疫抑制， 当代的策略专注于开发将有效的免疫刺激剂直接输送到肿瘤中的方法， 局部激发抗肿瘤T细胞以攻击表现出相似抗原性的播散性转移瘤。桥接 这些观察，这项提议的目标是设计出有选择性地定植的益生菌菌株 结直肠癌(CRC)局部释放免疫关卡阻断。我们假设这种方法 将导致更稳健和多样化的抗肿瘤T细胞免疫，促进定植的清除 原发和转移性结直肠癌病变和系统性生长的结直肠癌来源的病灶。初级阶段 这项提案的创新之处在于将益生菌工程作为免疫治疗的载体输送到当地 释放大剂量免疫检查点封锁。具体地说，建议的系统具有以下几个优点 目前的治疗策略包括：(1)针对肿瘤的免疫疗法和内毒素佐剂的生产， (2)细菌溶解，导致新型免疫疗法和内毒素的有效释放；(3)局部递送 全身给药有毒性的免疫疗法，以及(4)选择性地口服益生菌 使转移的结直肠癌定植。这项工作旨在改变当前的研究和临床实践范式，以克服 目前免疫疗法的局限性，通过提供一种独特的载体来在当地提供免疫疗法， 增强抗肿瘤免疫力，防止全身毒性，减轻IRAE。

PROJECT SUMMARY/ABSTRACT In recent years, the field of cancer immunotherapy has seen a renaissance – with the use of monoclonal antibodies that target immune checkpoints to activate anticancer immune responses demonstrating unparalleled clinical success. Several of these therapies have now gained FDA approval and are part of routine treatment regimens for several malignancies. Despite the overall success of immunotherapeutic regimens, existing modalities present complications that current research efforts seek to overcome: (1) systemic delivery of checkpoint blockade monoclonal antibodies lead to diverse and unpredictable immune-related adverse events (irAE), (2) boosting responses from the endogenous antitumor repertoire often relies on the existence of pre- primed antitumor T cells, which in the case of highly immunosuppressive tumors or those with low mutational burden may be extremely rare, and (3) attempts to combine immunotherapies to additively boost T cell responses demonstrate increased on-target, off-tumor toxicity. Thus, to circumvent toxicity and immunosuppression, contemporary strategies focus on developing methods to deliver potent immunostimulants directly into a tumor, locally priming antitumor T cells to attack disseminated metastases exhibiting a similar antigenic profile. Bridging these observations, the goals of this proposal are to engineer probiotic strains of bacteria that selectively colonize colorectal cancer (CRC) and locally release immune checkpoint blockade. We hypothesize that this approach will result in more robust and diversified antitumor T cell immunity and promote the clearance of colonized primary and metastatic colorectal cancer lesions and systemically growing CRC-derived foci. The primary innovations of this proposal are in engineering probiotics as an immunotherapeutic delivery vector to locally release high-dose immune checkpoint blockade. Specifically, the proposed system has several advantages over current therapeutic strategies, including: (1) tumor-specific production of immunotherapies and LPS adjuvant, (2) bacteria lysis, leading to effective release of novel immunotherapeutics and LPS, (3) local delivery of novel immunotherapeutics that are toxic to deliver systemically, and (4) oral delivery of probiotics that selectively colonize CRC metastases. This work seeks to shift current research and clinical practice paradigms to overcome current limitations of immunotherapies, by providing a unique vehicle to locally deliver immunotherapies that stimulate antitumor immunity while preventing systemic toxicity and mitigating irAE.