The Side Population (SP) analysis of GBM8401 and U-87 MG cancer cells.

(A) The SP percentage was analyzed in GBM8401 and U-87 MG cells by Hoechst staining and flow cytometry. The cells were incubated with the absence or presence of specific inhibitor Verapamil (100 μM) for 3 h. SP assay was performed followed by staining the cells with Hoechst33342 (5 μg/ml) for 90 min. The morphology of GBM8401 (B) and U-87 MG (C) parental and SP cells were monitored and photographed after the performance of SP Flow cytometry. The SP cells were incubated in serum-free conditioned medium for 1 week and the spheroid morphology was observed. The SP cells were differentiated into non-SP (NSP) cells for long-term culture in complete serum containing medium.