Analysis of the sensitivity of glioma stem cells to temozolomide

Abstract

Objective To investigate the sensitivity of glioma stem cells (GSC) to temozolomide (TMZ).MethodsFive GSC lines were successfully established from fresh glioma tissues.Immunofluoresence was employed to detect the expression of CD133 in undifferentiated GSC and glial fibriUary acid protein (GFAP) in differentiated GSC.The sensitivity of GSC was determined by using MTS.The percentage of CD133-positive cells was measured with flow cytometry.The methylation of MGMT promoter region in GSC was determined by using fluorescent methylation specific PCR (F-MSP).Western blotting was used to determine the protein level of PTEN in GSC.Results (1) The 5 established GSC lines demonstrated characteristics of cancer stem cells.(2) GSC lines were generally resistant to TMZ.The IC50 of TMZ was 22.3 μmol/L for T509,286.3 μmol/L for T411,and more than 1000 μmol/L for T402,T405 and T511,respectively.(3) GSC lines with more than 10% CD133-positive cells were more resistant to TMZ.(4) GSC lines with unmethylated MGMT promoter region were resistant or intermediately sensitive to TMZ.(5) The protein level of PTEN was different in the 5 GSC lines.No relationship between PTEN level and TMZ sensitivity was found.Conclusion A majority of GSC is resistant to TMZ,which is associated with the methylation status of MGMT promoter and CD133-positive cell population. Key words: Glioma; Glioma stem cells; Temozolomide; MGMT; CD133