Engineered Salmonella typhimurium (S.t-ΔpG^lux/pT-ClyA) and attenuated Salmonella typhimurium (SL: Salmonella typhimurium with a defect in the synthesis of guanine 5′-diphosphate-3′-diphosphate) exhibit similar tumor targeting capabilities (Kim et al. in Theranostics 5:1328–1342, 2015; Jiang et al. in Mol Ther 18:635–642, 2013), but S.t-ΔpG^lux/pT-ClyA exerts superior tumor suppressive effects. The aim of this study was to investigate whether S.t-ΔpG^lux/pT-ClyA inhibits colon cancer growth and recurrence by promoting increased IL-1β production. The CT26 tumor mouse model was used, and mice were treated in the following ways: PBS, S.t-ΔpG^{lux/pT-ClyA(+)} + IL-1βAb, SL, S.t-ΔpG^{lux/pT-ClyA(−)}, and S.t-ΔpG^{lux/pT-ClyA(+)}. Dynamic evaluation of the efficacy of S.t-ΔpG^lux/pT-ClyA in the treatment of colon cancer was assessed by MRI. Western blot, immunofluorescence and flow cytometry analysis were used to investigate IL-1β-derived cells and IL-1β expression on tumor cells and immune cells to analyze the regulatory mechanism. IL-1β levels in tumors colonized by S.t-ΔpG^lux/pT-ClyA were significantly increased and maintained at high levels compared to control treatments. This increase caused tumors to subside without recurrence. We examined the immune cells mediating S.t-ΔpG^lux/pT-ClyA-induced tumor suppression and examined the major cell types producing IL-1β. We found that macrophages and dendritic cells were the primary IL-1β producers. Inhibition of IL-1β in mice treated with S.t-ΔpG^lux/pT-ClyA using an IL-1β antibody caused tumor growth to resume. This suggests that IL-1β plays an important role in the treatment of cancer by S.t-ΔpG^lux/pT-ClyA. We found that in St-ΔpG^lux/pT-ClyA-treated tumors, expression of molecules involved in signaling pathways, such as NLRP3, ASC, Caspase1, TLR4, MyD88, NF-kB and IL-1β, were upregulated, while in ΔppGpp S. typhimurium treated animals, TLR4, MyD88, NF-kB and IL-1β were upregulated with NLRP3, ASC, and Caspase1 being rarely expressed or not expressed at all. Using S.t-ΔpG^lux/pT-ClyA may simultaneously activate TLR4 and NLRP3 signaling pathways, which increase IL-1β expression and enhance inhibition of colon cancer growth without tumor recurrence. This study provides a novel platform for treating colon cancer.

中文翻译：

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分泌lux / pT-ClyA工程菌可通过白介素1β在两种途径中抑制肿瘤生长

工程鼠伤寒沙门氏菌（圣-ΔpG^{勒克斯/ PT-ClyA}）和减毒鼠伤寒沙门氏菌（SL：鼠伤寒沙门氏菌在鸟嘌呤二磷酸-3'-二磷酸5'-合成的缺陷）表现出相似的肿瘤靶向能力（Kim等人。在治疗诊断5：1328年至1342年，2015; Jiang等人在分子疗法18：635-642，2013年），但圣-ΔpG^{勒克斯/ PT-ClyA}发挥优异的肿瘤抑制效果。这项研究的目的是调查是否圣-ΔpG^{勒克斯/ PT-ClyA}通过促进IL-1β产生的增加来抑制结肠癌的生长和复发。使用了CT26肿瘤的小鼠模型中，与小鼠通过以下方式进行处理：PBS，圣-ΔpG^{勒克斯/ PT-ClyA（+）}  + IL-1βAb，SL，圣-ΔpG^{勒克斯/ PT-ClyA（ - ）} ，和圣-ΔpG^{勒克斯/ PT-ClyA（+）} 。的功效的动态评估圣-ΔpG^{勒克斯/ PT-ClyA}在结肠癌的治疗中，通过MRI评估。用Western blot，免疫荧光和流式细胞术分析IL-1β来源的细胞以及IL-1β在肿瘤细胞和免疫细胞上的表达，以分析其调控机制。St- ΔpG定植的肿瘤中IL-1β的水平与对照治疗相比，^{lux / pT-ClyA}显着增加并维持在高水平。这种增加导致肿瘤消退而没有复发。我们检查了免疫细胞介导圣-ΔpG^{勒克斯/ PT-ClyA}诱导的肿瘤抑制和检查产生IL-1β主要细胞类型。我们发现巨噬细胞和树突状细胞是主要的IL-1β产生者。在小鼠IL-1β的抑制与治疗圣-ΔpG^{勒克斯/ PT-ClyA}使用IL-1β抗体引起肿瘤的生长恢复。这表明，IL-1β起着通过治疗癌症具有重要作用圣-ΔpG^{勒克斯/ PT-ClyA}。我们发现，在圣-ΔpG^{勒克斯/ PT-ClyA}处理的肿瘤，涉及信号通路的分子（例如NLRP3，ASC，Caspase1，TLR4，MyD88，NF-kB和IL-1β）的表达上调，而在ΔppGpp鼠伤寒沙门氏菌处理的动物中，TLR4，MyD88，NF- NLRP3，ASC和Caspase1很少表达或根本不表达，从而上调了kB和IL-1β。使用圣-ΔpG^{勒克斯/ PT-ClyA}可以同时激活TLR4和NLRP3信号传导途径，其增加IL-1β的表达并增强结肠癌生长的抑制没有肿瘤复发。该研究提供了治疗结肠癌的新平台。