Fig. 1
Growth of glioma tumor-initiating cells (GICs) in agarose and growth suppression of GICs in vitro and in vivo by drug treatments. a Number (left panels) and volume [total biomass (TBM), right panels] of colonies of GSC11 (upper panels) and GSC20 (lower panels) cells cultured in agarose were plotted against time and the growth curves were fitted to the Gompertzian curve. The coefficients of determination between actual and fitted data (R2) >0.99 in all panels. b GSC11 and GSC20 cells were seeded in agarose and treated with erlotinib at day 0, and the colony number was evaluated by using GelCount. Results shown are representative of three independent experiments. c, d GSC11 (c) and GSC20 (d) cells were seeded in agarose and treated with erlotinib and/or sorafenib after colony formation, and TBM was evaluated by using GelCount. Relative TBM to that at initiation of the treatment was plotted against time. Broken lines were for evaluation of doubling time to calculate tumor growth delay. Results shown are representative of three independent experiments done in duplicate. e Nude mice were inoculated with GSC11 cells, and after 1 week erlotinib and/or sorafenib were administered. The Kaplan–Meier survival curves were analyzed by log-rank test