Coordinating Cell Killing by Communication: Biological Control and Cancer Therapy

描述(申请人提供)：癌症治疗需要发展不同的治疗策略。为此，工程菌为有效地传递和表达具有治疗效果的基因以及选择性肿瘤靶向提供了希望。为了充分发挥细菌的治疗潜力，我们需要在多个层面上克服技术障碍。这些措施包括开发一个可以拼凑在一起执行治疗功能的遗传元件工具箱，以及更好地理解设计原则，从而能够精确控制实体肿瘤复杂微环境中的细菌动力学。为了应对这些挑战，这一应用程序的目标是使用细菌“群体感应”模块来协调不同环境中的细菌行为(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。建立在强大的初步数据的基础上，拟议的研究将专注于在大肠杆菌中设计、建模、实现和表征两个合成细菌多细胞系统。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之间的相互作用进行编程，这些细菌种群相互调节它们的基因表达；电路逻辑和动力学类似于研究得很好的捕食者-猎物生态系统。第二个(目标2.有针对性的共识回路)将通过两个相互沟通的细菌群体的协调决策，将细菌编程为具有高度特异性的肿瘤细胞。这项拟议的研究具有创新性，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。它的结果将为设计具有高度可靠行为的细菌用于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)一系列具有良好特性的遗传元件、模块和系统，(2)对在实体肿瘤等复杂环境中稳健控制细胞动力学的基本设计法则的洞察，以及(3)经过充分测试的建模工具和方法。所有这些都可以应用到建议系统之外的系统中，并将与生物医学研究社区共享。与公共卫生的相关性：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。这种方法将提供有效和安全的癌症治疗所需的极高的靶向选择性和细菌遏制效率。

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.