摘要
Objective: Irradiation may enhance migration and/or invasiveness of cancer cells in vitro and in vivo, the mechanism of which may be associated with epithelial-mesenchymal transition (EMT). The present study explored the mechanisms of EMT induced by irradiation in esophageal cancer cells. Methods: Human esophageal cancer cell line EC109 was treated with increased doses of irradiation (0 Gy, 20 Gy, 40 Gy and 60 Gy). Cell morphology was observed. Expressions of E-cadherin and vimentin were determined by immunofluorescence assay or western blot. Secretion of transforming growth factor-β1 (TGF-β1) by cells was determined by enzyme-linked immunosorbent assay (ELISA), and the expressions of Smad2/3 and phosphorated Smad2 (p-Smad2) were also examined by Western blot. The mRNA expressions of BMP-4, a bone morphogenetic protein (BMP) ligand, and two secreted BMP antagonists (Chordin and Gremlin), were detected with reverse transcription-polymerase chain reaction (RT-PCR). Cell migratory capacity was evaluated. Results: Irradiation induced EMT in EC109 cells in a dose-dependent manner as evidenced by morphological changes, decreased expression of E-cadherin and increased expression of vimentin, and increased cell motility. The secretion of TGF-β1 and expression of p-Smad2 were gradually increased in an irradiation dose-dependent manner, but the Smad2/3 protein levels remained stable. The mRNA expression of BMP-4 was gradually down-regulated, but the expressions of Chordin and Gremlin were gradually up-regulated in cells treated with increased doses of irradiation. Conclusion: Irradiation can induce EMT in esophageal cancer cells in a dose-dependent manner, and the mechanism may be associated with activation of TGF-β and restriction of BMP signaling.
Objective： Irradiation may enhance migration and/or invasiveness of cancer cells in vitro and in vivo, the mecha- nism of which may be associated with epithelial-mesenchymal transition （EMT）. The present study explored the mechanisms of EMT induced by irradiation in esophageal cancer cells. Methods： Human esophageal cancer cell line EC109 was treated with increased doses of irradiation （0 Gy, 20 Gy, 40 Gy and 60 Gy）. Cell morphology was observed. Expressions of E-cadherin and vimentin were determined by immunofluorescence assay or western blot. Secretion of transforming growth factor-β1 （TGF-β1） by cells was determined by enzyme-linked immunosorbent assay （ELISA）, and the expressions of Smad2/3 and phosphorated Smad2 （p-Smad2） were also examined by Western blot. The mRNA expressions of BMP-4, a bone mor- phogenetic protein （BMP） ligand, and two secreted BMP antagonists （Chordin and Gremlin）, were detected with reverse transcription-polymerase chain reaction （RT-PCR）. Cell migratory capacity was evaluated. Results： Irradiation induced EMT in EC109 cells in a dose-dependent manner as evidenced by morphological changes, decreased expression of E-cadherin and increased expression of vimentin, and increased cell motility. The secretion of TGF-β1 and expression of p-Smad2 were gradually increased in an irradiation dose-dependent manner, but the Smad2/3 protein levels remained stable. The mRNA expression of BMP-4 was gradually down-regulated, but the expressions of Chordin and Gremlin were gradually up-regulated in cells treated with increased doses of irradiation. Conclusion： Irradiation can induce EMT in esophageal cancer cells in a dose-dependent manner, and the mechanism may be associated with activation of TGF-β and restriction of BMP signaling.
基金
supported by a grant from the Huai'an City Science and Technology Support Program (Social Development) (No. HAS 2010010)
关键词
食管癌细胞
辐照诱导
EMT
BMP
信号
SMAD2
酶联免疫吸附试验
照射剂量
irradiation
epithelial-mesenchymal transition （EMT）
transforming growth factor （TGF）-β1
bone morphogeneticprotein （BMP）
esophageal cancer
