Original Article
Copyright ©2014 Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jun 28, 2014; 20(24): 7914-7925
Published online Jun 28, 2014. doi: 10.3748/wjg.v20.i24.7914
Distinct antifibrogenic effects of erlotinib, sunitinib and sorafenib on rat pancreatic stellate cells
Anne Elsner, Falko Lange, Brit Fitzner, Martin Heuschkel, Bernd Joachim Krause, Robert Jaster
Anne Elsner, Falko Lange, Brit Fitzner, Robert Jaster, Department of Medicine II, Division of Gastroenterology, University Medicine Rostock, 18057 Rostock, Germany
Brit Fitzner, Department of Neurology, University Medicine Rostock, 18119 Rostock, Germany
Martin Heuschkel, Bernd Joachim Krause, Department of Nuclear Medicine, University Medicine Rostock, 18057 Rostock, Germany
Author contributions: Elsner A and Lange F contributed equally to this work; Jaster R and Krause BJ designed the study; Elsner A, Lange F, Fitzner B and Heuschkel M performed the experiments; all authors analyzed the data; and Jaster R wrote the manuscript.
Supported by Grant from the Deutsche Forschungsgemeinschaft (to RJ)
Correspondence to: Robert Jaster, MD, Department of Medicine II, Division of Gastroenterology, University Medicine Rostock, E.-Heydemann-Str. 6, 18057 Rostock, Germany. jaster@med.uni-rostock.de
Telephone: +49-381-4947349 Fax: +49-381-4947482
Received: December 19, 2013
Revised: March 14, 2014
Accepted: April 8, 2014
Published online: June 28, 2014
Processing time: 189 Days and 11.5 Hours
Abstract

AIM: To study if three clinically available small molecule kinase inhibitors (SMI), erlotinib, sunitinib and sorafenib, exert antifibrogenic effects on pancreatic stellate cells (PSC) and analyze the basis of their action.

METHODS: Cultured rat PSC were exposed to SMI. Cell proliferation and viability were assessed employing 5-bromo-2’-deoxyuridine incorporation assay and flow cytometry, respectively. 2-Deoxy-2-[18F] fluoroglucose (18F-FDG) uptake was measured to study metabolic activity. Exhibition of the myofibroblastic PSC phenotype was monitored by immunofluorescence analysis of α-smooth muscle actin (α-SMA) expression. Levels of mRNA were determined by real-time PCR, while protein expression and phosphorylation were analyzed by immunoblotting. Transforming growth factor-β1 (TGF-β1) levels in culture supernatants were quantified by ELISA.

RESULTS: All three SMI inhibited cell proliferation and 18F-FDG uptake in a dose-dependent manner and without significant cytotoxic effects. Furthermore, additive effects of the drugs were observed. Immunoblot analysis showed that sorafenib and sunitib, but not erlotinib, efficiently blocked activation of the AKT pathway, while all three drugs displayed little effect on phosphorylation of ERK1/2. Cells treated with sorafenib or sunitinib expressed less interleukin-6 mRNA as well as less collagen type 1 mRNA and protein. Sorafenib was the only drug that also upregulated the expression of matrix metalloproteinase-2 and reduced the secretion of TGF-β1 protein. All three drugs showed insignificant or discordant effects on the mRNA and protein levels of α-SMA.

CONCLUSION: The tested SMI, especially sorafenib, exert inhibitory effects on activated PSC, which should be further evaluated in preclinical studies.

Keywords: Pancreatic stellate cell; Fibrosis; Erlotinib; Sunitinib; Sorafenib

Core tip: There are no specific therapies available to treat pancreatic fibrosis, a key feature of chronic pancreatitis and pancreatic cancer. Here we show that three clinically available small molecule kinase inhibitors (SMI), erlotinib, sunitinib and sorafenib, exert antifibrogenic effects in vitro by inhibiting key functions of rat pancreatic stellate cells (PSC), the main source of extracellular matrix proteins in the diseased pancreas. Furthermore, additive effects of the drugs were observed. Our studies also provide insight into molecular mechanisms of SMI action in PSC. We suggest that the antifibrotic efficiency of SMI, especially sorafenib, should be further evaluated in preclinical studies.