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


METHODS
Non-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.


RESULTS
In 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.


CONCLUSIONS
Wnt/β-catenin signaling is involved in enterocyte turnover during MTX-induced intestinal mucositis in a rat.
The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Laboratory of intestinal adaptation and recovery, Dept of Pediatric Surgery, Bnai Zion Medical Center, Haifa, Israel.
Igor
I
Sukhotnik
The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Laboratory of intestinal adaptation and recovery, Haifa, Israel.
Tatiana
T
Geyer
The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Laboratory of intestinal adaptation and recovery, Haifa, Israel.
Yulia
Y
Pollak
The Bruce Rappaport Faculty of Medicine, Dept of Pediatric Surgery, Bnai Zion Medical Center, Haifa, Israel.
Jorge G
JG
Mogilner
Section of Pediatric Surgery C.S. Mott Children's Hospital and University of Michigan Medical School, Ann Arbor, Michigan, United States of America.
Arnold G
AG
Coran
The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Dept of Pediatric Gastroenterology, Bnai Zion Medical Center, Haifa, Israel.
Drora
D
Berkowitz
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D018938:Caco-2 Cells; D049109:Cell Proliferation; D004195:Disease Models, Animal; D020895:Enterocytes / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000473:pathology; D007422:Intestines / Q000473:pathology; D008297:Male; D008727:Methotrexate; D052016:Mucositis / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D060449:Wnt Signaling Pathway / Q000502:physiology*; D051176:beta Catenin / Q000378:metabolism*
D051176:beta Catenin; D008727:Methotrexate