Estimation of the effectiveness ratio (α/β) for resistant cancer cells in U87MG human glioblastoma

Glioblastoma contains self-renewing, tumorigenic cancer stem-like cells that contribute to tumor initiation and therapeutic resistance. The aim of this research was to estimate and compare the effectiveness ratio (α/β) of stem-like cells and differentiated glioma cells derived from the U87MG glioblastoma cell line. Cell survival experiments were obtained in a dose range of 0-20 Gy (13.52 ± 0.09 Gy/h) as a hyperfractionationated accelerated radiotherapy scheme. Biochemical characterization of the post-irradiated cells was performed by flow cytometry analysis and the percentage of stem-like cells that resisted irradiation was determined by the CD133 expression. Results showed that U87MG stem-like cells are highly proliferative and more radioresistant than the U87MG adherent group (with a lesser stem-like character), this in association with the calculated α/β ratio of 17 and 14.1, respectively.