Fig. 4.

Dose-dependent effect of ascorbate on expression of HIF-1α and GLUT1. FTC-133 and 8305c cells were grown in medium containing cobalt chloride and were treated for 24 h with ascorbic acid stabilized with DTT. (a) Western blot analysis of HIF-1α, HIF-2α, GLUT1 and GLUT3 in thyroid cancer cells; (b) Results of densitometric analysis of relative HIF-1α and GLUT1 expressions in cells treated with different concentration of ascorbate; the results are shown as the mean ± SD; (c) Intracellular vitamin C level in FTC-133 and 8305c cells after ascorbate treatment; the results are shown as the mean ± SD. Experiments were performed in triplicate for three times; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001