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Oncogene. 2014 May 15;33(20):2639-54. doi: 10.1038/onc.2013.210. Epub 2013 Jun 10.

Utility of a bacterial infection model to study epithelial-mesenchymal transition, mesenchymal-epithelial transition or tumorigenesis.

Author information

1
Division of Gastroenterology, Department of Internal Medicine, Oklahoma City, OK, USA.
2
Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA.
3
Department of Anatomic and Surgical Pathology, University of Kansas Medical Center, Kansas City, KS, USA.
4
Carestream Molecular Imaging, Woodbridge, CT, USA.
5
1] Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA [2] The University of Kansas Cancer Center, University of Kansas Medical Center, Kansas City, KS, USA.

Abstract

DCLK1 and Lgr5 have recently been identified as markers of quiescent and cycling stem cells in the small intestinal crypts, respectively. Epithelial-mesenchymal transition (EMT) is a key development program that is often activated during cancer invasion and metastasis, and also imparts a self-renewal capability to disseminating cancer cells. Utilizing the Citrobacter rodentium (CR)-induced transmissible murine colonic hyperplasia (TMCH) model, we observed a relative decrease in DCLK1 expression in the colonic crypts, with significant shift towards stromal staining at peak (12 days post infection) hyperplasia, whereas staining for Lgr5 and Msi-1 increased several fold. When hyperplasia was regressing (days 20-34), an expansion of DCLK1+ve cells in the CR-infected crypts compared with that seen in uninfected control was recorded. Purified colonic crypt cells exhibiting epigenetic modulation of the transforming growth factor-β (TGFβ), Wnt and Notch pathways on 12 or 34 days post infection formed monolayers in vitro, and underwent trans-differentiation into fibroblast-like cells that stained positive for vimentin, fibronectin and DCLK1. These cells when trypsinized and regrown in soft agar, formed colonospheres/organoids that developed into crypt-like structures (colonoids) in Matrigel and stained positive for DCLK1. Mice exhibiting 12 or 34 days of TMCH were given azoxymethane once for 8 h (Gp1) or weekly for 3 weeks (Gp2), and subjected to crypt isolation. Crypt cells from Gp1 animals formed monolayers as well as colonospheres in soft agar and nodules/tumors in nude mice. Crypt cells isolated from Gp2 animals failed to form the monolayers, but developed into colonospheres in soft agar and nodules/tumors in nude mice. Thus, both hyperplasia and increased presence of DCLK1+ve cells promote cellular transformation in response to a second hit. The TMCH model, therefore, provides an excellent template to study how alterations in intestinal stem cells promote trans-differentiation, crypt regeneration or colon carcinogenesis following bacterial infection.

PMID:
23752178
PMCID:
PMC3883801
DOI:
10.1038/onc.2013.210
[Indexed for MEDLINE]
Free PMC Article

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