Ion channel TRPV1-dependent activation of PTP1B suppresses EGFR-associated intestinal tumorigenesis
Petrus R. de Jong, … , Maripat Corr, Eyal Raz
Petrus R. de Jong, … , Maripat Corr, Eyal Raz
Published August 1, 2014
Citation Information: J Clin Invest. 2014;124(9):3793-3806. https://doi.org/10.1172/JCI72340.
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Research Article Oncology

Ion channel TRPV1-dependent activation of PTP1B suppresses EGFR-associated intestinal tumorigenesis

Abstract

The intestinal epithelium has a high rate of turnover, and dysregulation of pathways that regulate regeneration can lead to tumor development; however, the negative regulators of oncogenic events in the intestinal epithelium are not fully understood. Here we identified a feedback loop between the epidermal growth factor receptor (EGFR), a known mediator of proliferation, and the transient receptor potential cation channel, subfamily V, member 1 (TRPV1), in intestinal epithelial cells (IECs). We found that TRPV1 was expressed by IECs and was intrinsically activated upon EGFR stimulation. Subsequently, TRPV1 activation inhibited EGFR-induced epithelial cell proliferation via activation of Ca2+/calpain and resulting activation of protein tyrosine phosphatase 1B (PTP1B). In a murine model of multiple intestinal neoplasia (ApcMin/+ mice), TRPV1 deficiency increased adenoma formation, and treatment of these animals with an EGFR kinase inhibitor reversed protumorigenic phenotypes, supporting a functional association between TRPV1 and EGFR signaling in IECs. Administration of a TRPV1 agonist suppressed intestinal tumorigenesis in ApcMin/+ mice, similar to — as well as in conjunction with — a cyclooxygenase-2 (COX-2) inhibitor, which suggests that targeting both TRPV1 and COX-2 has potential as a therapeutic approach for tumor prevention. Our findings implicate TRPV1 as a regulator of growth factor signaling in the intestinal epithelium through activation of PTP1B and subsequent suppression of intestinal tumorigenesis.

Authors

Petrus R. de Jong, Naoki Takahashi, Alexandra R. Harris, Jihyung Lee, Samuel Bertin, James Jeffries, Michael Jung, Jen Duong, Amy I. Triano, Jongdae Lee, Yaron Niv, David S. Herdman, Koji Taniguchi, Chang-Whan Kim, Hui Dong, Lars Eckmann, Stephanie M. Stanford, Nunzio Bottini, Maripat Corr, Eyal Raz

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Figure 5

TRPV1 regulates EGFR activity through calpain and PTP1B.

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TRPV1 regulates EGFR activity through calpain and PTP1B. (A) HCT116 cell...
(A) HCT116 cells were transfected with control or TRPV1 plasmid, then pretreated with DMSO or ALLM (10 μM) for 1 hour, followed by EGF (1 ng/ml) stimulation. Total cell lysates were analyzed by Western blotting. Lanes were run on the same gel. (B) HCT116 cells transfected with control or TRPV1 plasmid were pretreated with DMSO, the nonselective PTP inhibitor Na3VO4 (10 μM), or the selective PTP1B inhibitor Compound 3 (10 μM) for 1 hour, followed by EGF stimulation and Western blotting. (C) Q-PCR was performed for PTP candidates with RNA isolated from WT colon crypts. (D) HCT116 cells were treated with control or PTP1B siRNA and transfected with control or TRPV1 plasmid. Cells were then stimulated with EGF (1 ng/ml) and analyzed by Western blotting. Representative results of 2 independent experiments. (E) HCT116 cells were transfected with empty vector, WT PTP1B (PTP435), or PTP1B C-terminal truncation mutants (PTP370 and PTP377). Cells were stimulated with EGF (1 ng/ml) and analyzed by Western blotting. Representative results of 3 independent experiments. (F) PTP1B expression in intestinal organoids, shown by confocal fluorescent microscopy. (G) Expression of PTP1B in murine small intestinal tissue sections. Immunostaining for PTP1B and detection with DAB (brown) was followed by counterstaining with hematoxylin. (H) Q-PCR analysis of villus (V1 and V2) and crypt (C) fractions for Trpv1 and Ptpn1, showing enrichment in the latter. Values are expressed relative to the V1 fraction. Mean ± SEM (n = 3 per group). *P < 0.05, ANOVA. Scale bars: 100 μm.