Effects of Fractionated Radiation Exposure on Vimentin Expression in Cervical Cancers: Analysis of Association with Cancer Stem Cell Response and Short-Term Prognosis

Elucidation of the mechanisms for the response of cancer stem cells (CSCs) to radiation\nexposure is of considerable interest for further improvement of radio- and chemoradiotherapy of\ncervical cancer (CC). The aim of this work is to evaluate the effects of fractionated radiation exposure\non the expression of vimentin, which is one of the end-stage markers of epithelial-mesenchymal\ntransition (EMT), and analyze its association with CSC radiation response and short-term prognosis of\nCC patients. The level of vimentin expression was determined in HeLa, SiHa cell lines, and scrapings\nfrom the cervix of 46 CC patients before treatment and after irradiation at a total dose of 10 Gy using\nreal-time polymerase chain reaction (PCR) assay, flow cytometry, and fluorescence microscopy. The\nnumber of CSCs was assessed using flow cytometry. Significant correlations were shown between\nvimentin expression and postradiation changes in CSC numbers in both cell lines (R = 0.88, p = 0.04 for HeLa and R = 0.91, p = 0.01 for SiHa) and cervical scrapings (R = 0.45, p = 0.008). Associations were found at the level of tendency between postradiation increase in vimentin expression and unfavorable clinical outcome 3–6 months after treatment. The results clarify some of the relationships between EMT, CSCs, and therapeutic resistance that are needed to develop new strategies for cancer treatment.