Fig. 6.

GSK-3 inhibition overcomes rapamycin-resistance in ACHN cells. ACHN/P (parental) and ACHN/RR (rapamycin-resistant) cells were treated with increasing doses of rapamycin (a) and AR-A014418 (b) at 72 h. Cell viability was measured using MTS assay. Data are the mean ± SE in each from six replicates of each cells. In a and b, significant interaction between the main effects of cell lines (ACHN/P or ACHN/RR) and drug concentrations was statistically detected with two-way ANOVA (p < 0.05). As for the simple main effect, the difference in cell lines (ACHN/P or ACHN/RR) was statistically significant for rapamycin and not significant for AR-A014418 (one-way ANOVA with Bonferroni test; p < 0.05 and = 0.71, respectively). c ACHN/RR cells were treated with AR-A014418 (25 μM) or rapamycin (100 nM) at indicated times. The cells were lysed and analyzed for the phosphorylation of 4EBP1 and S6RP by immunoblotting. Data are representative of at least three separate immunoblot experiments