RESUMO
Objective:To observe the occurrence of epithelial-mesenchymal transition (EMT) in cervical cancer cell line Siha irradiated by X-rays with clinical conventional fraction radiotherapy model and investigate the role of exosomes in this process.Methods:Siha cells were irradiated by 6 MV-X rays with 50 Gy in 25 fractions. EMT was evaluated by cell morphology, EMT biomarkers and cell migration and invasion ability. Exosomes released from cells were detected by transmission electron microscopy and nanoparticle tracking analysis (NTA), and its function in EMT was explored by using an exosome inhibitor GW4869 (10 μmol/L).Results:After irradiation, EMT phenomenon was induced in the survived Siha cells, including the incidence of mesenchymal phenotype, upregulation of epithelial marker E-cadherin ( t=9.66, P<0.05), downregulation of mesenchymal marker N-cadherin ( t=41.61, P<0.05), and increase of cell migration and invasion abilities ( t=6.11, 13.22; P<0.05). Meanwhile, the secretion of exosomes was also increased after irradiation ( t=7.51, P<0.05). When the cells were pre-treated with GW4869, radiation-induced exosome secretion was reduced ( t=7.28, P<0.05), so that radiation-induced EMT was reversed. Conclusions:Ionizing radiation with clinical conventional fraction radiotherapy model promotes EMT of cervical cancer cells through increasing the secretion of exosomes.