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 8

Proposed model for EGFR-TRPV1 crosstalk in IECs.

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Proposed model for EGFR-TRPV1 crosstalk in IECs. TRPV1 and PTP1B are par...
TRPV1 and PTP1B are part of a homeostatic signaling circuit that restrains EGFR-induced epithelial cell proliferation. EGFR kinase activity mediates proproliferative and thus protumorigenic effects in IECs (dashed red arrows). TRPV1 and PTP1B are predominantly expressed in the crypt compartment that contains TA cells (dark blue cells) with active EGFR signaling. Ligand-induced autophosphorylation of the EGFR results in PLC activation, which cleaves PIP2, a tonic inhibitor of TRPV1, into diacylglycerol (DAG) and inositol triphosphate (IP3; green arrows). This results in TRPV1 triggering and Ca2+ influx, which activates calpain and subsequently PTP1B. PTP1B then dephosphorylates EGFR (blue lines). This coupling between EGFR and TRPV1 exerts negative feedback on growth factor receptor signaling, inhibits crypt progenitor cell (dark blue cells) turnover, and hence reduces the risk of intestinal neoplasia development (red cells). +4 ISC, ISC at +4 position; CBCC, crypt-based columnar stem cell.