Objective      To determine the effect of differential expression of heat shock protein B1 (HSPB1) in glioblastoma multiforme U251 cells and stem cells on tumor cell apoptosis.       Methods      U251 cells was cultured in a serum-free culture medium to obtain U251 stem cells

which were further identified by immunofluorescence staining of CD133 and of nestin for glioma stem cells. Isobaric tags for relative and absolute quantitation (iTRAQ) technology was used to detect the HSPs difference in U251 cells and stem cells.  MTT assay

Western blotting and RT-PCR were employed for the relationship of tumor cell apoptosis with HSPB1 expression at protein and mRNA levels after carmustine intervention.       Results      Glioma and glioma stem cells showed HSPB1 protein ratio of 0.523 without intervention carmustine. Carmustine intervention increased HSPB1 protein content by 1.4-fold and 3.3-fold

and HSPB1 mRNA by 1.5 times and 3.6 times respectively in U251 and stem cells. Carmustine at the same concentration also inhibited the growth of U251 cells

but not that of U251 stem cells.       Conclusion      HSPB1 might be involved in the process of chemotherapy resistance in U251 glioma cells

and play an important role in regulating tumor cell proliferation and apoptosis.