The germ-free mice monocolonization with Bacteroides fragilis improves azoxymethane/dextran sulfate sodium induced colitis-associated colorectal cancer

Yen Peng Lee, Chien Chao Chiu, Tien Jen Lin, Shao Wen Hung, Wen Ching Huang, Ching Feng Chiu, Yen Te Huang, Yi Hsun Chen, Ter Hsin Chen, Hsiao Li Chuang

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Objective: Inflammatory bowel disease (IBD) is generally considered as a major risk factor in the progression of colitis-associated colorectal cancer (CAC). Previous studies have indicated that the composition of gut microflora may be involved in CAC induction and progress. Bacteroides fragilis (BF) is a Gram-negative anaerobe belonging to colonic symbiotic bacteria of the host. This study was aimed to investigate the protective role of BF in a colorectal cancer (CRC) model induced by azoxymethane (AOM) and dextran sulfate sodium (DSS) in germ-free (GF) mice. Materials and methods: Total 22 GF mice were divided into two groups: GF and BF group. Half of the GF mice were colonized with BF for 28 days before CRC induction by AOM/DSS. Results:BF colonization increased animal survival (100%). Cecum weight and cecum/body weight ratio significantly decreased in BF/AOM/DSS group. Interestingly, there was a significant decrease in tumor number and tumor incidence in the BF/AOM/DSS group as compared to the GF/AOM/DSS group. The adenocarcinoma/adenoma incidence and histologic score were also decreased in the BF/AOM/DSS group. In addition, immunohistochemistry staining found decreased numbers of cell proliferation (PCNA) and inflammatory cell (granulocytes) infiltration in the colon mucosa of the BF group. The β-catenin staining in the BF/AOM/DSS group had fewer and weaker positive signal expressions. Taking together, the BF colonization significantly ameliorated AOM/DSS-induced CRC by suppressing the activity of cell proliferation-related molecules and reducing the number of inflammatory cells. Conclusions: Symbiotic BF may play a pivotal role in maintaining the gastrointestinal immunophysiologic balance and regulating anti-tumorigenesis responses.

Original languageEnglish
Pages (from-to)207-213
Number of pages7
JournalImmunopharmacology and Immunotoxicology
Volume41
Issue number2
DOIs
Publication statusPublished - Mar 4 2019

Keywords

  • anti-tumorigenesis
  • AOM
  • BF
  • CAC
  • DSS

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Toxicology
  • Pharmacology

Fingerprint Dive into the research topics of 'The germ-free mice monocolonization with Bacteroides fragilis improves azoxymethane/dextran sulfate sodium induced colitis-associated colorectal cancer'. Together they form a unique fingerprint.

  • Cite this