Antitumor Ability of Berberine Accompanied by Modulation of Gut Microbiome in Sarcoma-180 Tumor-bearing Mice

Abstract BackgroundAccumulating evidence indicates that sporamin, the main storage protein in the sweet potato (Ipomoea batatas), can suppress the development of colorectal cancer (CRC), but the changes in the gut microbiome after sporamin intervention and its relationships with the pathogenesis of CRC have not been investigated.MethodsTwelve male athymic BALB/c nude mice were randomly divided into four groups, CG1, CG2, TCG, and TTG. Mice in TCG and TTG were intraperitoneally transplanted with the LoVo cancer cells before the interventions started. CG2 and TTG were intragastrically infused with sporamin (0.5 g/kg BW/ day) for four weeks while CG1 and TCG were infused with the same volume of water during the experiment. Fecal samples were collected after the interventions and then examined for the changes in the microbiota using the 16S ribosomal RNA (rRNA) sequencing technology. The functional capabilities of the gut microbiota were predicted with the PICRUSt pipeline. Transcriptomic profiling of the tumor tissues was carried out for tumor-bearing mice with the RNA-sequencing (RNA-seq) technology and the resultant differentially expressed genes (DEGs) were then analyzed in terms of gene ontology (GO), protein-protein interaction (PPI), transcription factors (TF) prediction, and biological pathway annotations. ResultsSporamin significantly reduced the tumor burden of tumor-bearing mice and brought beneficial changes to the gut microbiome in both kinds of mice. It significantly increased the proportions of Barnesiella and Lactobacillus but reduced that of Bacteroides in tumor-bearing mice. The phenylalanine metabolism pathway, the glyoxylate, dicarboxylate metabolism, the bacterial secretion system, the glycan biosynthesis and metabolism, and the biosynthesis of stilbenoid, diarylheptanoid, and gingerol were favorably modulated by sporamin intervention. Sporamin mainly modulate the expression of the genes involved in the protein processing in the endoplasmic reticulum, the glycosylphosphatidylinositol (GPI)-anchor biosynthesis pathway, and the mineral absorption pathway. ConclusionSporamin could favorably alter the gut microbiome and its metabolome, improving the gut microenvironment and the viability of the gut microbiota and increasing the detoxification and bioactive substance production activities in the large intestine, by which the host’s metabolome may be altered and in turn exerts a suppressing effect on the protein synthesis and growth of tumor tissues.

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The Gut Microbiome Modulates Colon Tumorigenesis

mBio ◽

10.1128/mbio.00692-13 ◽

2013 ◽

Vol 4 (6) ◽

Cited By ~ 314

Author(s):

Joseph P. Zackular ◽

Nielson T. Baxter ◽

Kathryn D. Iverson ◽

William D. Sadler ◽

Joseph F. Petrosino ◽

...

Keyword(s):

Colorectal Cancer ◽

Colon Cancer ◽

Gut Microbiome ◽

Tumor Development ◽

Tumor Formation ◽

Normal Functioning ◽

Operational Taxonomic Units ◽

Tumor Bearing ◽

Colon Tumorigenesis

ABSTRACT Recent studies have shown that individuals with colorectal cancer have an altered gut microbiome compared to healthy controls. It remains unclear whether these differences are a response to tumorigenesis or actively drive tumorigenesis. To determine the role of the gut microbiome in the development of colorectal cancer, we characterized the gut microbiome in a murine model of inflammation-associated colorectal cancer that mirrors what is seen in humans. We followed the development of an abnormal microbial community structure associated with inflammation and tumorigenesis in the colon. Tumor-bearing mice showed enrichment in operational taxonomic units (OTUs) affiliated with members of the Bacteroides, Odoribacter, and Akkermansia genera and decreases in OTUs affiliated with members of the Prevotellaceae and Porphyromonadaceae families. Conventionalization of germfree mice with microbiota from tumor-bearing mice significantly increased tumorigenesis in the colon compared to that for animals colonized with a healthy gut microbiome from untreated mice. Furthermore, at the end of the model, germfree mice colonized with microbiota from tumor-bearing mice harbored a higher relative abundance of populations associated with tumor formation in conventional animals. Manipulation of the gut microbiome with antibiotics resulted in a dramatic decrease in both the number and size of tumors. Our results demonstrate that changes in the gut microbiome associated with inflammation and tumorigenesis directly contribute to tumorigenesis and suggest that interventions affecting the composition of the microbiome may be a strategy to prevent the development of colon cancer. IMPORTANCE The trillions of bacteria that live in the gut, known collectively as the gut microbiome, are important for normal functioning of the intestine. There is now growing evidence that disruptive changes in the gut microbiome are strongly associated with the development colorectal cancer. However, how the gut microbiome changes with time during tumorigenesis and whether these changes directly contribute to disease have not been determined. We demonstrate using a mouse model of inflammation-driven colon cancer that there are dramatic, continual alterations in the microbiome during the development of tumors, which are directly responsible for tumor development. Our results suggest that interventions that target these changes in the microbiome may be an effective strategy for preventing the development of colorectal cancer.

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