Pathogenesis of colorectal cancer (CRC) is associated with alterations in gut microbiome. Previous studies have focused on the changes of taxonomic abundances by metagenomics. Variations of the function of intestinal bacteria in CRC patients compared to healthy crowds remain largely unknown. Here we collected fecal samples from CRC patients and healthy volunteers and characterized their microbiome using quantitative metaproteomic method. We have identified and quantified 91,902 peptides, 30,062 gut microbial protein groups, and 195 genera of microbes. Among the proteins, 341 were found significantly different in abundance between the CRC patients and the healthy volunteers. Microbial proteins related to iron intake/transport; oxidative stress; and DNA replication, recombination, and repair were significantly alternated in abundance as a result of high local concentration of iron and high oxidative stress in the large intestine of CRC patients. Our study shows that metaproteomics can provide functional information on intestinal microflora that is of great value for pathogenesis research, and can help guide clinical diagnosis in the future.

大肠癌的发病机制与肠道微生物组的改变有关。以前的研究集中在宏基因组学对分类学丰度的改变上。与健康人群相比，CRC患者肠道细菌功能的变化仍然未知。在这里，我们收集了CRC患者和健康志愿者的粪便样本，并使用定量元蛋白质组学方法对他们的微生物组进行了表征。我们已经鉴定并量化了91,902个肽段，30,062个肠道微生物蛋白组和195个微生物属。在这些蛋白质中，发现341个CRC患者和健康志愿者的丰度显着不同。与铁摄入/运输有关的微生物蛋白；氧化应激 和DNA复制，重组，由于CRC患者大肠中局部高浓度的铁和高氧化应激，导致大量的修复和修复交替出现。我们的研究表明，元蛋白质组学可以提供有关肠道菌群的功能信息，这对于发病机理研究具有重要价值，并且可以帮助指导未来的临床诊断。