关键词: 脑肿瘤干细胞, 磁珠分选, 增殖, 分化, 致瘤性, 干细胞

Abstract:

BACKGROUND: The theory of brain tumor stem cells reports that brain tumor stem cell is the seed cell among brain tumor cells and is the key cell to occurrence, infiltration and recurrence of brain tumor.
OBJECTIVE: To investigate the biological characteristics of CD133⁺ cells in U251.
METHODS: CD133⁺ and CD133^- subpopulation cells in the human GBM U251 cell line were sorted by magnetic-activated cell sorting. The purification of CD133⁺ subpopulation was performed by flow cytometry. MTT and monoclone forming rate assay were performed to investigate the capacity of self-renewal and clonogenic potential of the subpopulation cells. Immunofluorescence staining was performed to investigate the multidiferentiation of CD133⁺ cells. The tumorigenic potential of the two subpopulation cells in vivo was investigated by xenografting in BALB/c nude mouse brain.
RESULTS AND CONCLUSION: Only 4.5% cells were CD133⁺ in the total population of U251 cell line. The CD133⁺ cells exhibited powerful proliferation capacity. The single CD133⁺ cell, rather than CD133^- cells, could proliferate and form typical brain tumor spheres. Cell growth curve showed that CD133⁺ cells proliferated remarkably faster than CD133- cells while cultured in serum-free medium. Monoclone forming rate of CD133+ and CD133- cells was 78.5-92.4% and 0.8-2.4% respectively. Immunofluorescence staining showed that CD133⁺ cells could be induced to differentiate into mature neurocyte cells. Xenograft assay showed that CD133⁺ cells had tumorigenic potential in vivo, while CD133^- had not. The U251 cell line contained a small proportion of CD133⁺ cells, which had the capacity for proliferation and multi- differentiation, and tumorigenic potential in vivo. The subpopulation of CD133⁺ cells was the brain tumor stem cell subpopulation in U251.