Enterotoxigenic Bacteroides fragilis induces the stemness in colorectal cancer via upregulating histone demethylase JMJD2B

Gut Microbes. 2020 Nov 9;12(1):1788900. doi: 10.1080/19490976.2020.1788900. Epub 2020 Jul 20.

Abstract

The enrichment of Enterotoxigenic Bacteroides fragilis (ETBF) has been identified in CRC patients and associated with worse prognosis. Cancer stem cells (CSCs) play essential roles in CRC development. However, whether ETBF is involved in CSCs regulation is unknown. To clarify the role of ETBF in CSCs properties, we performed extreme limited dilution assays (ELDA) in nude mice injected with ETBF-treated or untreated CRC cells subcutaneously, tumor organoids culture in azoxymethane (AOM) mouse model after gavaging with or without ETBF, and cell sphere formation assay after incubating CRC cell lines with or without ETBF. The results indicated that ETBF increased the stemness of CRC cells in vivo and in vitro. Furthermore, ETBF enhanced the expression of core stemness transcription factors Nanog homeobox (NANOG) and sex determining region Y-box 2 (SOX2). Histone H3 Lysine 9 trimethylation (H3K9me3) is critical in regulating CSCs properties. As an epigenetic and transcriptional regulator, JmjC-domain containing histone demethylase 2B (JMJD2B) is essential for embryonic stem cell (ESC) transformation and H3K9me3 demethylation. Mechanistically, ETBF infection significantly upregulated JMJD2B levels in CRC cell lines and nude mice xenograft model. JMJD2B epigenetically upregulated NANOG expression via demethylating its promoter H3K9me3, to mediate ETBF-induced stemness of CRC cells. Subsequently, we found that the Toll-like receptor 4 (TLR4) pathway, activated by ETBF, contributed to the enhanced expression of JMJD2B via nuclear transcription factor nuclear factor of activated T cells 5 (NFAT5). Finally, in human CRC samples, the amount of ETBF positively correlated with nuclear NFAT5, JMJD2B, and NANOG expression levels. In summary, ETBF upregulated JMJD2B levels in a TLR4-NFAT5-dependent pathway, and played an important role in stemness regulation, which promoted colorectal carcinogenesis.

Keywords: Enterotoxigenic Bacteroides fragilis; JMJD2B; colorectal cancer; histone demethylase; stemness.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacteroides fragilis / metabolism
  • Bacteroides fragilis / pathogenicity*
  • Carcinogenesis / metabolism
  • Carcinogenesis / pathology
  • Colorectal Neoplasms / genetics
  • Colorectal Neoplasms / metabolism
  • Colorectal Neoplasms / microbiology*
  • Colorectal Neoplasms / pathology*
  • Female
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Jumonji Domain-Containing Histone Demethylases / metabolism*
  • Male
  • Mice
  • Nanog Homeobox Protein / genetics
  • Nanog Homeobox Protein / metabolism
  • Neoplastic Stem Cells / metabolism
  • Neoplastic Stem Cells / microbiology
  • Neoplastic Stem Cells / pathology
  • Prognosis
  • SOXB1 Transcription Factors / genetics
  • SOXB1 Transcription Factors / metabolism
  • Toll-Like Receptor 4 / metabolism
  • Transcription Factors / metabolism

Substances

  • Nanog Homeobox Protein
  • Nanog protein, mouse
  • Nfat5 protein, mouse
  • SOXB1 Transcription Factors
  • Sox2 protein, mouse
  • Tlr4 protein, mouse
  • Toll-Like Receptor 4
  • Transcription Factors
  • Jumonji Domain-Containing Histone Demethylases
  • Kdm4b protein, mouse

Grants and funding

This study was supported by the National Natural Science Foundation of China (No. 81772506, 81530072, 81972203, 81802321), the funds from Shanghai Shenkang Center (SHDC12018121), and Shanghai Municipal Education Commission–Gaofeng Clinical Medicine Grant Support (No. 20152210).