Effectively targeting intracellular pathways in cancers requires a system that specifically delivers to tumors and internalizes into cancer cells. To achieve this goal, we developed intracellular-delivering (ID) Salmonella with controllable expression of flhDC, to regulate flagella production and cell invasion. We hypothesized that controlling flhDC would overcome the poor colonization seen in prior clinical trials. To test this hypothesis, we incorporated the aspirin-responsive Psal promoter and tuned flhDC expression with ssra degradation tags. In tumor-bearing mice, controlling flhDC increased protein release, tissue dispersion and tumor colonization more than ten million times. We discovered that inducing flhDC increases escape from intracellular vacuoles; however, deleting sseJ prevented escape and further increased protein delivery. Delivering constitutively active caspase-3 with ID-f-s Salmonella (ΔsseJ and induced PSal-flhDC) induced cell death in pancreatic, breast and liver cancer cells and reduced the growth of breast tumors. This clinically ready strain preferentially colonized metastatic breast tissue 280 and 800 times more than surrounding healthy tissue in the lung and liver, respectively. By precisely controlling tumor colonization and cell invasion, this strain overcomes critical limitations of bacterial therapy and will enable treatment of many hard-to-treat cancers444.

中文翻译：

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在临床相关的 ΔsseJ 沙门氏菌菌株中使用主调节因子 flhDC 控制细胞内蛋白质递送、肿瘤定植和组织分布。


有效靶向癌症中的细胞内通路需要一个专门递送至肿瘤并内化到癌细胞中的系统。为了实现这一目标，我们开发了细胞内递送 （ID） 沙门氏菌，具有可控的 flhDC 表达，以调节鞭毛的产生和细胞侵袭。我们假设控制 flhDC 将克服先前临床试验中观察到的不良定植。为了检验这一假设，我们掺入了阿司匹林反应性 Psal 启动子，并使用 ssra 降解标签调整了 flhDC 表达。在荷瘤小鼠中，控制 flhDC 使蛋白质释放、组织分散和肿瘤定植增加超过 1000 万倍。我们发现诱导 flhDC 会增加从细胞内液泡中逃逸;然而，删除 sseJ 可以防止逃逸并进一步增加蛋白质递送。用 ID-f-s 沙门氏菌 （ΔsseJ 和诱导的 PSal-flhDC） 递送组成型活性的 caspase-3 诱导胰腺癌、乳腺癌和肝癌细胞的细胞死亡，并减少乳腺肿瘤的生长。这种临床就绪菌株优先定植于肺和肝脏中转移性乳腺组织的定植率分别是周围健康组织的 280 倍和 800 倍。通过精确控制肿瘤定植和细胞侵袭，该菌株克服了细菌治疗的关键限制，并将能够治疗许多难以治疗的癌症444。