Diminished expression of CRHR2 in human colon cancer promotes tumor growth and EMT via persistent IL-6/Stat3 signaling

Jorge A Rodriguez; Sara Huerta-Yepez; Ivy Ka Man Law; Guillermina J Baay-Guzman; Belen Tirado-Rodriguez; Jill M Hoffman; Dimitrios Iliopoulos; Daniel W Hommes; Hein W Verspaget; Lin Chang; Charalabos Pothoulakis; Stavroula Baritaki

doi:10.1016/j.jcmgh.2015.08.001

Diminished expression of CRHR2 in human colon cancer promotes tumor growth and EMT via persistent IL-6/Stat3 signaling

Cell Mol Gastroenterol Hepatol. 2015 Nov 1;1(6):610-630. doi: 10.1016/j.jcmgh.2015.08.001.

Affiliations

¹ IBD Center, Division of Digestive Diseases, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
² Unidad de Investigacion en Enfermedades Oncologicas, Hospital Infantil de Mexico Federico Gomez, Mexico City, Mexico.
³ Center for Systems Biomedicine, Division of Digestive Diseases, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
⁴ IBD Center, Division of Digestive Diseases, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA ; Dept. of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, The Netherlands.
⁵ Dept. of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, The Netherlands.
⁶ Gail and Gerard Oppenheimer Family Center for Neurobiology of Stress, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
⁷ IBD Center, Division of Digestive Diseases, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA ; Unidad de Investigacion en Enfermedades Oncologicas, Hospital Infantil de Mexico Federico Gomez, Mexico City, Mexico ; Division of Surgery, School of Medicine, University of Crete, Heraklion, Crete, Greece.

Abstract

Background & aims: Chronic inflammation promotes development and progression of colorectal cancer (CRC). We explored the distribution of Corticotropin-Releasing-Hormone (CRH)-family of receptors and ligands in CRC and their contribution in tumor growth and oncogenic EMT.

Methods: mRNA expression of CRH-family members was analyzed in CRC (N=56) and control (N=46) samples, 7 CRC cell lines and normal NCM460 cells. Immunohistochemical detection of CRHR2 was performed in 20 CRC and 5 normal tissues. Cell proliferation, migration and invasion were compared between Urocortin-2 (Ucn2)-stimulated parental and CRHR2-overexpressing (CRHR2+) cells in absence or presence of IL-6. CRHR2/Ucn2-targeted effects on tumor growth and EMT were validated in SW620-xenograft mouse models.

Results: CRC tissues and cell lines showed decreased mRNA and protein CRHR2 expression compared to controls and NCM460, respectively. The opposite trend was shown for Ucn2. CRHR2/Ucn2 signaling inhibited cell proliferation, migration, invasion and colony formation in CRC-CRHR2+ cells. In vivo, SW620-CRHR2+ xenografts showed decreased growth, reduced expression of EMT-inducers and elevated levels of EMT-suppressors. IL-1b, IL-6 and IL-6R mRNAs where diminished in CRC-CRHR2+ cells, while CRHR2/Ucn2 signaling inhibited IL-6-mediated Stat3 activation, invasion, migration and expression of downstream targets acting as cell cycle- and EMT-inducers. Expression of cell cycle- and EMT-suppressors was augmented in IL-6/Ucn2-stimulated CRHR2+ cells. In patients, CRHR2 mRNA expression was inversely correlated with IL-6R and vimentin levels and metastasis occurrence, while positively associated with E-cadherin expression and overall survival.

Conclusions: CRHR2 downregulation in CRC supports tumor expansion and spread through maintaining persistent inflammation and constitutive Stat3 activation. CRHR2^low CRC phenotypes are associated with higher risk for distant metastases and poor clinical outcomes.

Keywords: colorectal cancer; inflammation; metastasis; neuropeptides.

Diminished expression of CRHR2 in human colon cancer promotes tumor growth and EMT via persistent IL-6/Stat3 signaling

Authors

Affiliations

Abstract

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