Mutated CEACAMs Disrupt Transforming Growth Factor Beta Signaling and Alter the Intestinal Microbiome to Promote Colorectal Carcinogenesis
Mutated CEACAMs Disrupt Transforming Growth Factor Beta Signaling and Alter the Intestinal Microbiome to Promote Colorectal Carcinogenesis
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DOI：
10.1053/j.gastro.2019.09.023
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发表时间：
2020-01-01
期刊：
影响因子：
29.4
通讯作者：
Mishra, Lopa
中科院分区：
文献类型：
--
作者：
Gu, Shoujun;Zaidi, Sobia;Mishra, Lopa
背景与目的：我们研究了与微生物相互作用的癌胚抗原相关细胞粘附分子（CEACAM）家族的蛋白质之间的相互作用，以及转化生长因子β（TGFB）信号通路，该通路在结直肠癌细胞中经常改变。我们研究了CEACAM蛋白抑制TGFB信号传导并改变肠道微生物组以促进结直肠癌发生的机制。方法：我们收集了来自456例结直肠腺癌病例的DNA序列、信使RNA表达水平和患者生存时间的数据，以及一组单独的594例结直肠腺癌样本，载于癌症基因组图谱。我们对野生型小鼠和TGFB信号缺陷小鼠（Sptbn 1（+/-）和Smad 4（+/-）/Sptbn 1（+/-））的粪便进行了鸟枪宏基因组测序分析，以确定结肠肿瘤发生前微生物群组成的变化。CEACAM蛋白及其突变体在SW 480和HCT 116结直肠癌细胞系中过表达，通过免疫印迹和增殖和集落形成测定来分析。研究结果：在结直肠腺癌中，编码CEACAM蛋白的基因，特别是CEACAM 5的高表达水平与患者的生存时间缩短相关。CEACAM基因的表达与TGF β通路基因（TGF β R 1、TGF β R 2和SMAD 3）的表达呈负相关。在结直肠腺癌中，我们还发现TGFB信号通路中的基因表达与调节细胞干细胞特征的基因表达之间呈负相关。我们在结直肠腺癌中发现了编码人CEACAM 5 B3结构域L 640 I和A643 T的突变;结构研究表明这些突变将改变CEACAM 5和TGFBR 1之间的相互作用。这些突变体在SW 480和HCT 116结直肠癌细胞系中的过表达增加了它们的锚定非依赖性生长，并且比野生型CEACAM 5的过表达更大程度地抑制了TGFB信号传导，表明它们是功能获得性突变。与野生型小鼠的粪便相比，TGFB信号缺陷小鼠的粪便中与结肠肿瘤发展相关的细菌种类（包括败血性梭菌）的丰度增加，而有益细菌（如普通拟杆菌和Distasonis副拟杆菌）的数量减少。结论：我们发现CEACAMs和调节细胞干细胞特征的基因的表达在结直肠腺癌中增加，并且与TGFB通路基因的表达呈负相关。我们发现结直肠腺癌表达CEACAM 5的突变形式，其抑制TGFB信号传导并增加增殖和集落形成。我们认为CEACAM蛋白破坏TGFB信号传导，从而改变肠道微生物组的组成，促进结直肠癌的发生。
BACKGROUND & AIMS: We studied interactions among proteins of the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family, which interact with microbes, and transforming growth factor beta (TGFB) signaling pathway, which is often altered in colorectal cancer cells. We investigated mechanisms by which CEACAM proteins inhibit TGFB signaling and alter the intestinal microbiome to promote colorectal carcinogenesis. METHODS: We collected data on DNA sequences, messenger RNA expression levels, and patient survival times from 456 colorectal adenocarcinoma cases, and a separate set of 594 samples of colorectal adenocarcinomas, in The Cancer Genome Atlas. We performed shotgun metagenomic sequencing analyses of feces from wild-type mice and mice with defects in TGFB signaling (Sptbn1(+/-) and Smad4(+/-)/Sptbn1(+/-)) to identify changes in microbiota composition before development of colon tumors. CEACAM protein and its mutants were overexpressed in SW480 and HCT116 colorectal cancer cell lines, which were analyzed by immunoblotting and proliferation and colony formation assays. RESULTS: In colorectal adenocarcinomas, high expression levels of genes encoding CEACAM proteins, especially CEACAM5, were associated with reduced survival times of patients. There was an inverse correlation between expression of CEACAM genes and expression of TGFB pathway genes (TGFBR1, TGFBR2, and SMAD3). In colorectal adenocarcinomas, we also found an inverse correlation between expression of genes in the TGFB signaling pathway and genes that regulate stem cell features of cells. We found mutations encoding L640I and A643T in the B3 domain of human CEACAM5 in colorectal adenocarcinomas; structural studies indicated that these mutations would alter the interaction between CEACAM5 and TGFBR1. Overexpression of these mutants in SW480 and HCT116 colorectal cancer cell lines increased their anchorage-independent growth and inhibited TGFB signaling to a greater extent than overexpression of wild-type CEACAM5, indicating that they are gain-of-function mutations. Compared with feces from wild-type mice, feces from mice with defects in TGFB signaling had increased abundance of bacterial species that have been associated with the development of colon tumors, including Clostridium septicum, and decreased amounts of beneficial bacteria, such as Bacteroides vulgatus and Parabacteroides distasonis. CONCLUSION: We found expression of CEACAMs and genes that regulate stem cell features of cells to be increased in colorectal adenocarcinomas and inversely correlated with expression of TGFB pathway genes. We found colorectal adenocarcinomas to express mutant forms of CEACAM5 that inhibit TGFB signaling and increase proliferation and colony formation. We propose that CEACAM proteins disrupt TGFB signaling, which alters the composition of the intestinal microbiome to promote colorectal carcinogenesis.