Cellular biofactories for therapeutic protein synthesis in tumor microenvironment

 描述（由申请人提供）：T细胞经历基于抑制性和兴奋性趋化性输入的智能决策过程;并通过实体组织屏障扩散到肿瘤微环境。研究人员的长期目标是在R33阶段将T细胞开发成一种平台载体技术，用于将药物主动转运到实体瘤。在这项R21申请中，他们的目标是设计一种强大的机制，将自体T细胞转化为生物工厂，以便在肿瘤细胞刺激下自主合成杀细胞分泌蛋白。具有时空分辨率的感兴趣蛋白（PoI）的自主合成将能够以细胞分辨率和分子特异性靶向肿瘤负荷。他们的中心假设是，T细胞可以被遗传编码用于在肿瘤部位对治疗性蛋白质的稳健调节和生物合成。他们选择了表达叶酸受体α（FRa）的卵巢癌作为疾病模型，并选择了一种具有细胞毒性治疗价值的凋亡蛋白。然而，将T细胞开发为蛋白质生物工厂的基本原理是，这是一种平台技术，它们的特异性可以被修改， 靶向任何癌症并在原位自主合成任何PoI。为了帮助R21的工作，他们开发了表达生物发光和荧光报告基因的细胞系，这些报告基因仅在受到肿瘤细胞刺激时表达。有了以下具体目标，他们将推动该项目朝着其 目的：（1）开发对目的蛋白（PoI）生物合成的鲁棒控制;（2）开发T 细胞作为自主分泌抗肿瘤凋亡蛋白的生物工厂。预期该R21期将导致T细胞在健康组织中不会活化（增强的安全性）， 在肿瘤微环境中特异性地过度活化（增强的功效）。这项研究的影响也将通过减少移植物抗宿主病（GVHD）的发生率而对正在进行的T细胞治疗试验产生影响。这种开创性的方法建立在正在进行的T细胞免疫治疗试验的基础上，这些试验目前仅限于控制微小残留病（MRD），并在化疗后进行。拟议的研究是变革性的，首先是因为它将扩大T细胞工程的范围，以取代全身化疗。然后，这将用于减少肿瘤负荷，而不是保持MRD在检查。其次，非人类来源的治疗性蛋白质被免疫系统有效地降解和去除。这是其体内应用的障碍。使用自体T细胞在靶位点生物合成治疗性蛋白质将消除任何免疫原性问题。预期会产生异常高的影响，因为T细胞的特异性可以重定向到不同癌症的表面标志物，因此可以用于靶向多种癌症。

 DESCRIPTION (provided by applicant): T cells undergo an intelligent decision-making process based on the inhibitory and excitatory chemotactic inputs; and extravagate to the tumor microenvironment through solid tissue barriers. Investigators' long-term goal, to be pursued in R33 phase, is to develop T cells into a platform vector technology for active drug- transport to the solid tumors. In this R21 application, their objective is to engineer a robust mechanism to transform autologous T cells into biofactories for autonomous synthesis of cytocidal secretory proteins upon stimulation by the tumor cells. Autonomous synthesis of Protein-of-Interest (PoI) with spatiotemporal resolution will enable targeting of tumor burden with cellular resolution and molecular specificity. Their central hypothesis is that T cells can be genetically encoded for robust modulation and biosynthesis of therapeutic proteins at the tumor site. They have chosen ovarian cancer that expresses Folate Receptor alpha (FRa) as disease model, and an apoptotic protein for its cytotoxic therapeutic value. However, the rationale for developing T cells as protein biofactories is that this is a platform technology and their specificity can be modified to target any cancer and autonomously synthesize any PoI in situ. To aid this R21 effort, they have developed cell lines expressing bioluminescent and fluorescent reporters expressed only when stimulated by tumor cells. With following specific aims, they will advance this project towards its goals: (1) To develop robust control on biosynthesis of protein-of-interest (PoI); (2) To develop T cells as biofactories for autonomous secretion of antitumor apoptotic protein. It is expected that this R21 phase will lead to T cells that will not activate in healthy tissues (enhanced safety) and hyperactivate specifically in the tumor microenvironment (enhanced efficacy). The impact of this research will also be felt on ongoing T-cell therapy trials by reducing the incidences of graft-versus-host-disease (GVHD). This pioneering approach builds upon ongoing T-cell immunotherapy trials, which are currently limited to control minimal residual disease (MRD) and is administered after chemotherapy. Proposed research is transformative, firstly because it will expand the scope of T-cell engineering to replace systemic chemotherapies. This will then be used for reduction of tumor burden rather than keeping MRD in check. Secondly, therapeutic proteins of non-human origin are efficiently degraded and removed by the immune system. This is a barrier to their in vivo application. The use of autologous T cells for biosynthesis of therapeutic proteins at the target site will eliminate any immunogenicity issues. Unusually high impact is expected because the specificity of T cells can be redirected towards the surface markers on different cancers and therefore be used to target multitude of cancers.