A. AdEcSOD increases the degradation rate of HIF-1α protein. MIA PaCa-2 cells were treated with cycloheximide (100 μM) to inhibit protein synthesis. The levels of HIF-1α protein and β-actin with either AdEmpty or AdEcSOD (100 MOI) were analyzed after exposure to 4% O2. The degradation rate of HIF-1α was increased by overexpression of EcSOD.
B. EcSOD did not affect HIF-1α protein synthesis. MIA PaCa-2 cells were treated with MG-132 (10 μM) to inhibit protein degradation through the proteasome. Levels of HIF-1α and β-actin in cells treated with either AdEmpty or AdEcSOD infection were determined over a period of 2 h. The amount of HIF-1α protein was unchanged in the presence of MG-132 after treatment with EcSOD.