Fig. 1

Depletion of glutamine reduced SP subpopulation cells. a The human lung cancer A549 cell line was maintained in standard RPMI 1640 medium containing 2000 mg/l glucose and 300 mg/l glutamine. A portion of the cells were switched to glutamine-free RPMI 1640 medium (upper panels) and another portion of cells was switched to glucose-free RPMI 1640 medium (lower panels). The cells cultured under these different conditions were analyzed for percentage of SP cells at 24 h, 48 h and 72 h. The result of flow cytometry from one representative experiment is shown. b Relative quantification of SP fractions under the experiment conditions described in A. Data are means ± SD of 3 independent experiments; *, p < 0.05; **, p < 0.01; ***, p < 0.001. Glc, glucose; Gln, glutamine; Vera, Verapamil