The role of Wnt/β-catenin signaling in enterocyte turnover during methotrexate-induced intestinal mucositis in a rat.

Igor Sukhotnik,Drora Berkowitz,Tatiana Geyer,Jorge G Mogilner,Yulia Pollak,Arnold G Coran,Bart O Williams

doi:10.1371/journal.pone.0110675

Abstract

Background/AimsIntestinal mucositis is a common side-effect in patients who receive aggressive chemotherapy. The Wnt signaling pathway is critical for establishing and maintaining the proliferative compartment of the intestine. In the present study, we tested whether Wnt/β-catenin signaling is involved in methotrexate (MTX)-induced intestinal damage in a rat model.MethodsNon-pretreated and pretreated with MTX Caco-2 cells were evaluated for cell proliferation and apoptosis using FACS analysis. Adult rats were divided into three experimental groups: Control rats; MTX-2 animals were treated with a single dose of MTX given IP and were sacrificed on day 2, and MTX-4 rats were treated with MTX similar to group B and were sacrificed on day 4. Intestinal mucosal damage, mucosal structural changes, enterocyte proliferation, and enterocyte apoptosis were measured at sacrifice. Real Time PCR and Western blot was used to determine the level of Wnt/β-catenin related genes and protein expression.ResultsIn the vitro experiment, treatment with MTX resulted in marked decrease in early cell proliferation rates following by a 17-fold increase in late cell proliferation rates compared to early proliferation. Treatment with MTX resulted in a significant increase in early and late apoptosis compared to Caco-2 untreated cells. In the vivo experiment, MTX-2 and MTX-4 rats demonstrated intestinal mucosal hypoplasia. MTX-2 rats demonstrated a significant decrease in FRZ-2, Wnt 3A Wnt 5A, β-catenin, c-myc mRNA expression and a significant decrease in β-catenin and Akt protein levels compared to control animals. Four days following MTX administration, rats demonstrated a trend toward a restoration of Wnt/β-catenin signaling especially in ileum.ConclusionsWnt/β-catenin signaling is involved in enterocyte turnover during MTX-induced intestinal mucositis in a rat.

Highlights

Oral and gastrointestinal mucositis is a frequent dose-limiting and costly side effect of cytoreductive cancer chemotherapy which affects more than three-fourths of patients [1,2]
Wnt/b-catenin signaling is involved in enterocyte turnover during MTX-induced intestinal mucositis in a rat
The purpose of this study was to evaluate the role of Wnt/bcatenin signaling during recovery from chemotherapy-induced mucositis in a rat model

Summary

Introduction

Oral and gastrointestinal mucositis is a frequent dose-limiting and costly side effect of cytoreductive cancer chemotherapy which affects more than three-fourths of patients [1,2]. Mucositis represents a significant burden to patients and caregivers It leads to dose reduction or prevention of continuation of selected cancer therapies, increases healthcare cost, prolongs hospital stay, increases re-admission rates, compromises patients’ nutritional status, impairs patients’ quality of life, and is occasionally fatal [3]. Chemotherapy may exert celldamaging or a cell-destroying effect through the generation of reactive oxygen species [5], or through enzymatic or transcription factors (NF-kB) which leads to up regulation of genes responsible for production of proinflammatory cytokines TNF-a, IL-1b and IL-62. This leads to tissue injury and apoptosis [6]

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