Toll-like receptor 5 engagement modulates tumor development and growth in a mouse xenograft model of human colon cancer
Toll-like receptor 5 engagement modulates tumor development and growth in a mouse xenograft model of human colon cancer
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DOI：
10.1053/j.gastro.2008.04.022
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发表时间：
2008-08-01
期刊：
影响因子：
29.4
通讯作者：
Pothoulakis, Charalabos
中科院分区：
文献类型：
--
作者：
Rhee, Sang Hoon;Im, Eunok;Pothoulakis, Charalabos
背景和目标：Toll样受体（TLR）依赖的信号转导被认为是抵抗入侵病原体和肿瘤发生的免疫靶点。在这里，我们研究了TLR 5依赖性信号传导是否调节人结肠癌小鼠异种移植模型中结肠肿瘤的发展。方法：稳定敲低人结肠癌细胞（DLD-1）中髓样分化因子88（MyD 88）或TLR 5的表达。裸鼠皮下植入MyD 88敲低（KD）、TLR 5-KD或对照细胞（n = 16）以检查肿瘤异种移植物的病理生理学。蛋白质芯片评估这些肿瘤中细胞因子的差异表达。白细胞浸润和肿瘤血管生成通过免疫组织化学评估，分别与中性粒细胞（Gr-1，7/4）或巨噬细胞特异性抗原（CD 68，F4-80）和血管内皮细胞标志物CD 31的抗体。用鞭毛蛋白处理来自DLD-1细胞的肿瘤异种移植物（5.0 μ g/kg，1次注射/每2天，持续3周），并检查肿瘤消退和组织病理学。结果：MyD 88或TLR 5表达的缺乏显著增强了人结肠癌小鼠异种移植物中的肿瘤生长并抑制了肿瘤坏死。相比之下，通过瘤周鞭毛蛋白处理的TLR 5活化显著增加了肿瘤坏死，导致显著的肿瘤消退。来自MyD 88-KD或TLR 5-KD细胞的肿瘤显示中性粒细胞吸引趋化因子（上皮细胞衍生的嗜中性粒细胞活化肽-78、巨噬细胞炎性蛋白α和白细胞介素-8）的产生减少。因此，在MyD 88或TLR 5-KD异种移植物中，中性粒细胞浸润显著减少，而肿瘤相关的巨噬细胞浸润或血管生成没有改变。结论：鞭毛蛋白介导的TLR 5参与介导先天免疫和增强的抗肿瘤活性，表明TLR 5依赖性信号传导可能是调节结肠肿瘤的潜在免疫靶点。
Background & Aims: Toll-like receptor (TLR)-dependent signaling was proposed as immunotherapeutic targets against invading pathogens and tumorigenesis. Here, we investigated whether TLR5-dependent signaling modulates colonic tumor development in mouse xenograft model of human colon cancer. Methods: The expression of myeloid differentiation factor 88 (MyD88) or TLR5 was stably knocked down in human colon cancer cells (DLD-1). Nude mice were subcutaneously implanted with MyD88-knocked down (KD), TLR5-KD, or control cells (n = 16) to examine the pathophysiology of tumor xenografts. Protein microarray assessed the differential expression of cytokines in these tumors. Leukocyte infiltration and tumor angiogenesis were assessed by immunohistochemistry with antibodies against neutrophil (Gr-1, 7/4) or macrophage-specific antigens (CD68, F4-80) and the vascular endothelial cell marker CD31, respectively. Tumor xenografts from DLD-1 cells were treated with flagellin (5.0 mu g/kg, 1 injection/every 2 days for 3 weeks), and tumor regression and histopathology were examined. Results: Lack of MyD88 or TLR5 expression dramatically enhanced tumor growth and inhibited tumor necrosis in mouse xenografts of human colon cancer. In contrast, TLR5 activation by peritumoral flagellin treatment substantially increased tumor necrosis, leading to significant tumor regression. Tumors from MyD88-KD or TLR5-KD cells revealed the reduced production of neutrophil attracting chemokines (epithelial cell-derived neutrophil-activating peptide-78, macrophage-inflammatory protein alpha, and interleukin-8). Consequently, neutrophil infiltration was dramatically diminished in MyD88- or TLR5-KD xenografts, whereas tumor-associated macrophage infiltration or angiogenesis was not changed. Conclusions: TLR5 engagement by flagellin mediates innate immunity and elicits potent antitumor activity, indicating that TLR5-dependent signaling could be a potential immunotherapeutic target to modulate colonic tumors.