The Preliminary Study On Radiosensitivity Of Glioma Cells In Hypoxia Through Cancer Stem Cell

Objective: This study was designed to observe whether microenvironment hypoxia could influence radiosensitivity of glioma cells through cancer stem cell.Methods: SHG44 and U251 glioma cells were cultured in serum-based or serum-free cell growth medium at 20% or 1% O₂ for 12 and 24 hrs in vitro, respectively. The cells expressing CD133 were measured by flow cytometry. The in vitro colony-forming assay was used to investigate the radiosensitivity.Results: (1) SHG44 and U251 glioma cells cultured in serum-free cell growth medium contained a higher fraction of tumor cells expressing CD133 and had lower radiosensitivity than the cells cultured in serum-based medium. (2) These two types of glioma cells cultured in serum-based medium contained a higher fraction of tumor cells expressing CD133 and had lower radiosensitivity under 1% O₂ for 12 or 24 hrs compared to 20%. (3) These two types of glioma cells cultured in serum-free cell growth medium contained a higher fraction of tumor cells expressing CD133 and had lower radiosensitivity under 1% O₂ for 12 or 24 hrs compared to 20%.Conclusions: (1) The fractional enrichment of stem cells decreased radiosensitivity of SHG44 and U251 glioma cells. (2) Whether in serum-free cell growth or serum-based medium, the fractional enrichment of stem cells by hypoxia could increase radioresistance of SHG44 and U251 glioma cell lines, and the further study of underlying mechanism is needed.