Proliferation and apoptosis of glioma stem cells after Gamma knife treatment

Abstract

Objective To research the proliferation and apoptosis of glioma stem cells after Gamma knife treatment.Methods The glioma stem cells were cultured in serum-free suspension; real time-PCR was used to detect the CD133 expression; fluorescence staining was employed to observe the expressions of nestin,glial fibrillary acidic protein (GFAP) and [3-tubulin after stem cell differentiation.After 10 Gy Gamma knife treatment for 48 h,the glioma U87 cell and stem cell survival was detected under microscope; after 15 Gy Gamma knife treatments for 8-10 h,immunofluorescent staining was performed to detect the 5-bromodeoxyuridine (BrdU)-positive cells; flow cytometry was employed to compare the changes of cell apoptosis before and after 10 and 15 Gy Gamma knife treatment.Results Under the culture conditions of serum-free medium,glioma stem cells became spherical suspended growth and had proliferation and self-renewal capacity,expressing CD133 and nestin,and containing the ability to differentiate into astrocytes and neural elements.After 10 Gy gamma knife treatments,the cell survival in the glioma stem cells was significantly higher than that in the U87 cells (86±3 vs.22±2,P＜0.05).About 35％ glioma stem cells showed positive BrdU staining before 15 Gy gamma knife treatment and it was about 22％ after treatment with statistical difference (P＜0.05).The apoptosis rate in the glioma stem cells was low; that in cells with 15 Gy gamma knife treatment (0.312±0.011) was significantly higher than that in cells with 10 Gy gamma knife treatment (0.112±0.014,P＜0.05).Conclusions Under the culture conditions of serum-free medium,glioma stem cells can be derived from human glioma tissue.Treatment of gamma knife could inhibit the proliferation of glioma stem cells,causing their apoptosis.As compared with glioma cells,glioma stem cells are not sensitive to gamma knife radiotherapy and radio-resistant. Key words: Glioma;  Glioma stem cell;  Gamma knife;  Proliferation;  Apoptosis