Engineering Salmonella to be a targeted intratumoral anti-cancer therapeutic

描述（由申请人提供）：将鼠伤寒沙门氏菌工程化为靶向抗癌治疗剂被工程化为特异性靶向肿瘤的治疗抗性区域并可控地杀死癌细胞的细菌将能够克服治疗抗性并增加癌症治疗的功效。治疗抗性是由有限的药物渗透和差的细胞敏感性引起的。只有能够渗透到肿瘤组织中并克服扩散限制的能动细菌才能够有效地杀死远离肿瘤脉管系统的治疗抗性细胞。因此，控制细菌运动性是开发能够克服治疗抗性的有效疗法的关键。迄今为止，肿瘤中细菌运动的机制知之甚少。我们的方法将阐明这些机制，并将操纵它们以靶向肿瘤静止。该项目是独一无二的，因为它引入了肿瘤内治疗传递的概念和圆柱体肿瘤模型，该模型专门用于量化肿瘤中的细菌趋化性。拟议的研究计划有三个具体目标，结合联合收割机在肿瘤生物学，分子生物学和数学建模的专业知识。它们是相互关联的，将同时进行：目的1是确定控制S的机制。目的二是设计S.目的3是产生具有增强靶向性的鼠伤寒沙门氏菌突变体;具有增加的肿瘤细胞毒性的鼠伤寒沙门氏菌突变体。研究计划的三个假设是：1）S。2）核糖受体敲除S.鼠伤寒沙门氏菌优先在肿瘤静止区聚集;表达辐射诱导的细胞毒性多肽有效载荷的鼠伤寒沙门氏菌将更有效地减少肿瘤质量。这些假设将通过测量S的定位来检验。鼠伤寒沙门氏菌在小鼠肿瘤中，删除核糖受体从S。鼠伤寒沙门氏菌基因组，并转化S.在RecA启动子的控制下表达mTRAIL多肽。将在培养物和小鼠中测量转化细菌减少肿瘤质量的效率。该实验计划是一项研究计划的一部分，旨在开发一种治疗策略以克服治疗耐药性。肿瘤静止期靶向S.鼠伤寒沙门氏菌和辅助化疗将通过更有效地杀死远离肿瘤脉管系统的癌细胞来提高治疗效率。未来的人体试验将研究细菌和化疗联合给药减少四期乳腺癌患者局部复发和转移性疾病的能力。使用细菌来克服治疗耐药性和提高治疗效率将显著降低全身毒性，限制转移性疾病的有害影响，并增加预期寿命。实验计划描述了一种治疗策略，以克服治疗耐药性使用静止靶向，可控细胞毒性S。鼠伤寒。工程菌和辅助化疗的联合给药将通过更有效地杀死肿瘤中的所有癌细胞来提高治疗效率。这种增加的功效将减少全身毒性，防止局部复发，限制转移性疾病的有害影响，并增加预期寿命。

DESCRIPTION (provided by applicant): Engineering Salmonella typhimurium to be a targeted anti-cancer therapeutic Bacteria engineered to specifically target therapeutically resistant regions of tumors and controllably kill cancer cells will be able to overcome therapeutic resistance and increase the efficacy of cancer treatment. Therapeutic resistance is caused by limited drug penetration and poor cell susceptibility. Only motile bacteria, which can penetrate into tumor tissue and overcome diffusion limitations, are able to effectively kill therapeutically resistant cells distant from tumor vasculature. Controlling bacterial motility is therefore the key to developing effective therapies able to overcome therapeutic resistance. To date, the mechanisms of bacterial motility in tumors are poorly understood. Our approach will elucidate these mechanisms and will manipulate them to target tumor quiescence. The project is unique because it introduces the concept of intratumoral therapeutic delivery and the cylindroid tumor model, which was specifically designed to quantify bacterial chemotaxis in tumors. The proposed research program has three Specific Aims that combine expertise in tumor biology, molecular biology, and mathematical modeling. They are interrelated and will be performed concurrently: Aim 1 is to determine the mechanisms that control S. typhimurium accumulation in tumors; Aim 2 is to design S. typhimurium mutants with enhanced targeting; and Aim 3 is to create S. typhimurium mutants with increased tumor cytotoxicity. The three hypotheses of the research plan are: 1) S. typhimurium are attracted to and induce cellular apoptosis in tumors, 2) ribose-receptor-knockout S. typhimurium preferentially accumulate in quiescent regions of tumors, and 3) S. typhimurium expressing a radiation-inducible, cytotoxic polypeptide payload will more effectively reduce tumor mass. These hypotheses will be tested by measuring the localization of S. typhimurium in mouse tumors, deleting the ribose receptor from the S. typhimurium genome, and transforming S. typhimurium to express the mTRAIL polypeptide under control of the RecA promoter. The efficiency of the transformed bacteria to reduce tumor mass will be measured in culture and in mice. The experimental plan is part of a research program to develop a therapeutic strategy to overcome therapeutic resistance. Combined administration of tumor-quiescence-targeted S. typhimurium and adjuvant chemotherapy will increase therapeutic efficiency by more effectively killing cancer cells distant from tumor vasculature. Future human trials will investigate the ability of combined administration of bacteria and chemotherapy to reduce local recurrence and metastatic disease in stage-four breast cancer patients. Using bacteria to overcome therapeutic resistance and increase treatment efficiency will significantly reduce systemic toxicity, limit the deleterious effects of metastatic disease, and increase life expectancy. The experimental plan descries a therapeutic strategy to overcome therapeutic resistance using quiescence- targeted, controllably cytotoxic S. typhimurium. Combined administration of engineered bacteria and adjuvant chemotherapy will increase therapeutic efficiency by more effectively killing all cancer cells in tumors. This increased efficacy will reduce systemic toxicity, prevent local recurrence, limit the deleterious effects of metastatic disease, and increase life expectancy.