FIGURE 10.

Glucose variation-induced stress increases Pgp-mediated cell resistance to DOX (A) while increasing cell sensitivity to Dp44mT (B) and DpC (C). MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays measuring cellular toxicity of DOX (72 h at 37 °C) (A), Dp44mT (24 h at 37 °C) (B), or DpC (24 h at 37 °C) (C) in KB31 (i), KBV1 (ii), MCF7 (iii), MDA-MB-231 (iv), and HCT-15 cells (v) supplemented with low (0 mm), normal (25 mm), or high (50 mm) glucose medium for 2 h at 37 °C before and during drug treatment in the presence or absence of the Pgp inhibitor, Ela (0.2 μm), 30 min before and for the duration of DOX treatment. Results in A--C are the mean ± S.D. (n = 4). *, p < 0.05; **, p < 0.01, and ***, p < 0.001 are relative to normal glucose (25 mm); #, p < 0.05; ##, p < 0.01, and ###, p < 0.001 are relative to the respective control glucose treatments (e.g. KBV1 0 mm glucose versus KBV1 0 mm glucose + Ela).