Engineering immunotherapeutic probiotics to mitigate irAE

项目概要/摘要 近年来，癌症免疫治疗领域出现了复兴-使用单克隆抗体， 靶向免疫检查点以激活抗癌免疫应答的抗体， 临床成功这些疗法中有几种现在已经获得了FDA的批准，并成为常规治疗的一部分 几种恶性肿瘤的治疗方案。尽管免疫治疗方案总体上取得了成功，但现有的 目前的研究努力试图克服的方式提出的并发症：（1）系统性交付的 检查点阻断单克隆抗体导致多种和不可预测的免疫相关不良事件 （2）来自内源性抗肿瘤库的增强应答通常依赖于前抗肿瘤抗体的存在。 致敏的抗肿瘤T细胞，在高度免疫抑制肿瘤或具有低突变的肿瘤的情况下， 负担可能是极其罕见的，以及（3）尝试联合收割机免疫疗法以相加地增强T细胞应答 表现出增加的靶向、脱肿瘤毒性。因此，为了避免毒性和免疫抑制， 目前的策略集中于开发将有效的免疫刺激剂直接递送到肿瘤中的方法， 局部引发抗肿瘤T细胞攻击表现出相似抗原谱的播散性转移。桥接 根据这些观察结果，该提案的目标是设计选择性定植的益生菌菌株， 结直肠癌（CRC）和局部释放免疫检查点阻断。我们假设这种方法 将导致更强大和多样化的抗肿瘤T细胞免疫，并促进清除定植的 原发性和转移性结直肠癌病变以及全身生长的CRC源性病灶。主 该建议的创新在于将益生菌工程化为免疫递送载体， 释放高剂量免疫检查点阻断。具体而言，所提出的系统具有几个优点， 目前的治疗策略包括：（1）肿瘤特异性产生免疫疗法和LPS佐剂， (2)细菌裂解，导致新型免疫治疗剂和LPS的有效释放，（3）新型免疫治疗剂的局部递送， 全身递送有毒的免疫治疗剂，和（4）选择性地 定植于CRC转移灶。这项工作旨在改变目前的研究和临床实践范式，以克服 通过提供一种独特的载体来局部递送免疫疗法， 刺激抗肿瘤免疫，同时防止全身毒性和减轻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.