Fig. 9. Episodic hypoxia provides resistance to apoptosis. (A) Representative Western blot of HIF-1α, Procaspase-3 and active Caspase-3 after apoptosis induction with 1 µM staurosporine during 3 h re-oxygenation. DCT cells were prior exposed to the different types of hypoxia. Tubulin served as a loading control. (B) Quantitation of HIF-1α protein levels. Asterisks denote significance between staurosporine treated groups *: p<0.05, **: p<0.01, ***: p<0.001. Error bars indicate standard deviation (n=3). (C) Quantitation of Procaspase-3 protein levels as in (B). (D) Quantitation of active Caspase-3 protein levels as in (B). Shown in white bars in each graph are the protein levels in untreated cells in normoxia. This can be used as a comparison for the effect of staurosporine on apoptosis in the absence of hypoxia in these cells.