Dataset Information

Shifts of Faecal Microbiota During Sporadic Colorectal Carcinogenesis.

ABSTRACT: Gut microbiota has been implicated in the etiopathogenesis of colorectal cancer. The development of colorectal cancer is a multistep process by which healthy epithelium slowly develops into preneoplastic lesions, which in turn progress into malignant carcinomas over time. In particular, sporadic colorectal cancers can arise from adenomas (about 85% of cases) or serrated polyps through the "adenoma-carcinoma" or the "serrated polyp-carcinoma" sequences, respectively. In this study, we performed 16?S rRNA gene sequencing of bacterial DNA extracted from faecal samples to compare the microbiota of healthy subjects and patients with different preneoplastic and neoplastic lesions. We identified putative microbial biomarkers associated with stage-specific progression of colorectal cancer. In particular, bacteria belonging to the Firmicutes and Actinobacteria phyla, as well as members of the Lachnospiraceae family, proved to be specific of the faecal microbiota of patients with preneoplastic lesions, including adenomas and hyperplastic polyps. On the other hand, two families of the Proteobacteria phylum, Alcaligeneaceae and Enterobacteriaceae, with Sutterella and Escherichia/Shigella being the most representative genera, appeared to be associated with malignancy. These findings, once confirmed on larger cohorts of patients, can represent an important step towards the development of more effective diagnostic strategies.

SUBMITTER: Mori G

PROVIDER: S-EPMC6037773 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature

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Shifts of Faecal Microbiota During Sporadic Colorectal Carcinogenesis.

Mori Giorgia G Rampelli Simone S Orena Beatrice Silvia BS Rengucci Claudia C De Maio Giulia G Barbieri Giulia G Passardi Alessandro A Casadei Gardini Andrea A Frassineti Giovanni Luca GL Gaiarsa Stefano S Albertini Alessandra M AM Ranzani Guglielmina Nadia GN Calistri Daniele D Pasca Maria Rosalia MR

Scientific reports 20180709 1

Gut microbiota has been implicated in the etiopathogenesis of colorectal cancer. The development of colorectal cancer is a multistep process by which healthy epithelium slowly develops into preneoplastic lesions, which in turn progress into malignant carcinomas over time. In particular, sporadic colorectal cancers can arise from adenomas (about 85% of cases) or serrated polyps through the "adenoma-carcinoma" or the "serrated polyp-carcinoma" sequences, respectively. In this study, we performed 1 ...[more]

PMID: 29985435

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Project description:BackgroundObesity is a risk factor for colorectal cancer (CRC). The role of gut microbiota in mediating the cancer-promoting effect of obesity is unknown.MethodsAzoxymethane (AOM)-treated, ApcMin/+ and germ-free mice were gavaged with feces from obese individuals and control subjects respectively. The colonic tumor load and number were recorded at the endpoint in two carcinogenic models. The gut microbiota composition and colonic transcriptome were assessed by metagenomic sequencing and RNA sequencing, respectively. The anticancer effects of bacteria depleted in fecal samples of obese individuals were validated.FindingsConventional AOM-treated and ApcMin/+ mice receiving feces from obese individuals showed significantly increased colon tumor formation compared with those receiving feces from control subjects. AOM-treated mice receiving feces from obese individuals showed impaired intestinal barrier function and significant upregulation of pro-inflammatory cytokines and activation of oncogenic Wnt signaling pathway. Consistently, transferring feces from obese individuals to germ-free mice led to increased colonic cell proliferation, intestinal barrier function impairment, and induction of oncogenic and proinflammatory gene expression. Moreover, germ-free mice transplanted with feces from obese human donors had increased abundance of potential pathobiont Alistipes finegoldii, and reduced abundance of commensals Bacteroides vulgatus and Akkermansia muciniphila compared with those receiving feces from human donors with normal body mass index (BMI). Validation experiments showed that B. vulgatus and A. muciniphila demonstrated anti-proliferative effects in CRC, while A. finegoldii promoted CRC tumor growth.InterpretationOur results supported the role of obesity-associated microbiota in colorectal carcinogenesis and identified putative bacterial candidates that may mediate its mechanisms. Microbiota modulation in obese individuals may provide new approaches to prevent or treat obesity-related cancers including CRC.FundingThis work was funded by National Key Research and Development Program of China (2020YFA0509200/2020YFA0509203), National Natural Science Foundation of China (81922082), RGC Theme-based Research Scheme Hong Kong (T21-705/20-N), RGC Research Impact Fund Hong Kong (R4632-21F), RGC-CRF Hong Kong (C4039-19GF and C7065-18GF), RGC-GRF Hong Kong (14110819, 14111621), and NTU Start-Up Grant (021337-00001).

Project description:Invasive growth of epithelial cancers is a complex multi-step process which involves dissolution of the basement membrane. Type IV collagen is a major component in most basement membranes. Type VII collagen is related to anchoring fibrils and is found primarily in the basement membrane zone of stratified epithelia. Immunohistochemical studies have previously reported changes in steady-state levels of different alpha(IV) chains in several epithelial cancer types. In the present study we aimed to quantitatively determine the mRNA levels of type IV collagen (alpha1/alpha 4/alpha 6) and type VII collagen (alpha1) during colorectal cancer carcinogenesis.Using quantitative RT-PCR, we have determined the mRNA levels for alpha1(IV), alpha 4(IV), alpha 6(IV), and alpha1(VII) in colorectal cancer tissue (n = 33), adenomas (n = 29) and in normal tissue from the same individuals. In addition, corresponding tissue was examined from healthy volunteers (n = 20). mRNA levels were normalized to beta-actin. Immunohistochemical analysis of the distributions of type IV and type VII collagens were performed on normal and affected tissues from colorectal cancer patients.The alpha1(IV) and alpha1(VII) mRNA levels were statistically significantly higher in colorectal cancer tissue (p < 0.001) as compared to corresponding tissue from healthy controls. This is an early event as tissue from adenomas also displayed a higher level. There were small changes in the levels of alpha 4(IV). The level of alpha 6(IV) was 5-fold lower in colorectal cancer tissue as compared to healthy individuals (p < 0.01). The localisation of type IV and type VII collagen was visualized by immunohistochemical staining.Our results suggest that the down-regulation of alpha 6(IV) mRNA coincides with the acquisition of invasive growth properties, whereas alpha1(IV) and alpha1(VII) mRNAs were up-regulated already in dysplastic tissue. There are no differences in collagen expression between tissues from healthy individuals and normal tissues from affected individuals.

Dataset Information

Shifts of Faecal Microbiota During Sporadic Colorectal Carcinogenesis.

Publications

Shifts of Faecal Microbiota During Sporadic Colorectal Carcinogenesis.

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