Coordinating Cell Killing by Communication: Biological Control and Cancer Therapy

描述（由申请人提供）：癌症治疗需要多种治疗策略的发展。为此，工程细菌为有效传递和表达具有治疗效果的基因以及选择性靶向肿瘤提供了希望。为了充分发挥细菌的治疗潜力，我们需要克服多个层面的技术障碍。其中包括开发一个遗传元素工具箱，可以将其拼凑在一起以执行治疗功能，以及更好地理解设计原则，以便在实体肿瘤的复杂微环境中精确控制细菌动力学。为了应对这些挑战，本应用程序的目标是使用细菌“群体感应”模块来协调细菌在不同环境中的行为（生命、死亡、空间聚集）。群体感应是细菌感知和响应其种群密度变化的一种机制。基于强有力的初步数据，拟议的研究将集中在大肠杆菌中两种合成细菌多细胞系统的设计、建模、实现和表征上。第一个系统（目标1）。（捕食者-猎物系统）将试图对两个细菌种群相互调节其基因表达的相互作用进行编程；电路的逻辑和动力学类似于经过充分研究的捕食者-猎物生态系统。第二个（目标2）。一个有针对性的共识电路（targeted consensus circuit）将通过两个相互沟通的细菌群体的协调决策，使细菌以高特异性靶向肿瘤细胞。这项提议的研究是创新的，因为它扩展了合成生物学的基本概念和设计方法，以解决癌症治疗的紧迫问题。其结果将为具有高度可靠行为的工程细菌的治疗应用奠定坚实的基础，从而产生重大影响。特别是，预期的结果包括(1)一系列特征良好的遗传元件、模块和系统，(2)对复杂环境（如实体肿瘤）中细胞动力学鲁棒控制的基本设计定律的见解，以及(3)经过彻底测试的建模工具和方法。所有这些都可以应用于拟议的系统之外，并将与生物医学研究界共享。与公共卫生的相关性：这项拟议的研究将填补限制工程设计策略应用于癌症靶向细菌开发的重要空白。这种方法将为有效和安全的癌症治疗提供极高的靶向选择性和细菌控制效率。

DESCRIPTION (provided by applicant): Cancer treatment requires development of diverse therapeutic strategies. To this end, engineered bacteria offer promise for efficiently delivering and expressing genes with therapeutic effects and for selective tumor targeting. To fully realize bacteria's therapeutic potential, we need to overcome technological hurdles at multiple levels. These include development of a toolbox of genetic elements that can be pieced together to carry out therapeutic functions and a better understanding of design principles that will enable precise control of bacterial dynamics in the complex micro-environments of solid tumors. To address these challenges, the objective of this application is to use bacterial "quorum sensing" modules to coordinate bacterial behavior (life, death, spatial aggregation) in diverse settings. Quorum sensing is a mechanism by which bacteria sense and respond to changes in their population density. Built upon strong preliminary data, the proposed research will focus on design, modeling, implementation, and characterization of two synthetic bacterial multicellular systems in Escherichia coli. The first system (Aim 1. a predator-prey system) will attempt to program the interaction of two bacterial populations that mutually regulate their gene expression; the circuit logic and dynamics resemble well-studied predator-prey ecosystems. The second (Aim 2. a targeted consensus circuit) will program bacteria to target tumor cells with high specificity through coordinated decision making by two communicating bacterial populations. The proposed research is innovative, because it extends basic concepts and design methods of synthetic biology to address the pressing issue of cancer therapy. Its outcome will have significant impact by setting a solid foundation for engineering bacteria with highly reliable behavior for therapeutic applications. In particular, expected outcomes include (1) a repertoire of well-characterized genetic elements, modules, and systems, (2) insights into fundamental design laws for robust control of cellular dynamics in complex environments such as solid tumors, and (3) thoroughly tested modeling tools and methods. All of these can be applied in systems beyond the proposed ones and will be shared with the biomedical research community. Relevance to Public Health: The proposed research will fill the important gap that limits the application of engineering design strategies to the development of cancer-targeting bacteria. This approach will offer the extremely high targeting selectivity and bacterial containment efficiency needed for effective and safe cancer therapy.