Relationship between Fusobacterium nucleatum, inflammatory mediators and microRNAs in colorectal carcinogenesis

Title: Relationship between Fusobacterium nucleatum, inflammatory mediators and microRNAs in colorectal carcinogenesis
Authors: Proença, Marcela Alcântara
Biselli, Joice Matos
Succi, Maysa
Hughes, David J.
et al.
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Date: 21-Dec-2018
Online since: 2019-05-28T07:39:40Z
Abstract: AIM: To examine the effect of Fusobacterium nucleatum (F. nucleatum) on the microenvironment of colonic neoplasms and the expression of inflammatory mediators and microRNAs (miRNAs). METHODS: Levels of F. nucleatum DNA, cytokine gene mRNA (TLR2, TLR4, NFKB1, TNF, IL1B, IL6 and IL8), and potentially interacting miRNAs (miR-21-3p, miR-22-3p, miR-28-5p, miR-34a-5p, miR-135b-5p) were measured by quantitative polymerase chain reaction (qPCR) TaqMan® assays in DNA and/or RNA extracted from the disease and adjacent normal fresh tissues of 27 colorectal adenoma (CRA) and 43 colorectal cancer (CRC) patients. KRAS mutations were detected by direct sequencing and microsatellite instability (MSI) status by multiplex PCR. Cytoscape v3.1.1 was used to construct the postulated miRNA:mRNA interaction network. RESULTS:Overabundance of F. nucleatum in neoplastic tissue compared to matched normal tissue was detected in CRA (51.8%) and more markedly in CRC (72.1%). We observed significantly greater expression of TLR4, IL1B, IL8, and miR-135b in CRA lesions and TLR2, IL1B, IL6, IL8, miR-34a and miR-135b in CRC tumours compared to their respective normal tissues. Only two transcripts for miR-22 and miR-28 were exclusively downregulated in CRC tumour samples. The mRNA expression of IL1B, IL6, IL8 and miR-22 was positively correlated with F. nucleatum quantification in CRC tumours. The mRNA expression of miR-135b and TNF was inversely correlated. The miRNA:mRNA interaction network suggested that the upregulation of miR-34a in CRC proceeds via a TLR2/TLR4-dependent response to F. nucleatum. Finally, KRAS mutations were more frequently observed in CRC samples infected with F. nucleatum and were associated with greater expression of miR-21 in CRA, while IL8 was upregulated in MSI-high CRC. CONCLUSION:Our findings indicate that F. nucleatum is a risk factor for CRC by increasing the expression of inflammatory mediators through a possible miRNA-mediated activation of TLR2/TLR4.
Type of material: Journal Article
Publisher: Baishideng
Journal: World Journal of Gastroenterology
Volume: 24
Issue: 47
Start page: 5351
End page: 5365
Copyright (published version): 2018 the Authors
Keywords: Colorectal cancerColorectal adenomaFusobacterium nucleatumInflammationCytokinesMicroRNAs
DOI: 10.3748/wjg.v24.i47.5351
Language: en
Status of Item: Peer reviewed
Appears in Collections:Biomolecular and Biomedical Science Research Collection

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