Fig. 1.

Concentration- and time-dependent modulation of HIF-1α protein levels by As(III) under normoxia and hypoxia. Cells were cultured under normoxia (16 % O₂) for 24 h. After 24 h, the medium was changed and cells were further cultured under normoxia and hypoxia (5 % O₂) and treated either with: a different concentrations of As(III) for 4 h; b 50 μM As(III) for the indicated time points. The HIF-1α levels in the absence of As(III) or in controls at 0 h were set to 1. Values represent mean ± SEM of at least three independent experiments. Single asterisk, significant difference control under normoxia vs. As(III); double asterisks, significant difference control under hypoxia vs. As(III). c Representative Western blot with 50 μM As(III) at 4 h. One hundred micrograms of total protein was subjected to Western blot analysis with an antibody against HIF-1α or Golgi membrane (GM). Autoradiographic signals were visualized by chemiluminescence and quantified by video densitometry