Figure 3.

Vitamin C increases the proline hydroxylation of HIF-1α. A. HLE-B3 cells were pretreated with MG-132 and then treated without or with vitamin C plus MG-132 for 6 or 12 h, the levels of proline hydroxylation of HIF-1α (hydroxy P402/564) and β-actin were examined by Western Blot from HLE-B3 cells. B. HLE-B3 cells were stably transfected with wild-type HIF-1α/proline-mutant HIF-1α or negative control. Expression of HIF-1α and β-actin were examined by Western Blot. C. HLE-B3 cells stably co-expressing an HRE-driven luciferase expression vector and wild-type HIF-1α or proline-mutant HIF-1α or negative control were treated without or with vitamin C for 12 h. Relative luciferase units were subsequently measured using a luminometer; *P<0.008 compared with each of the control untreated group.