1, 9 PA downregulates HIF-1α in a PHD- and HIF-1α ODD-dependent manner.

<p>(A) Requirement of O₂ and Fe²⁺ in the 1, 9 PA-induced downregulation of HIF-1α. A431 cells were untreated or treated with 10 µM 1, 9 PA in 0.5% FBS culture medium under normoxic conditions in the absence or presence of DFO (100 µM) or MG132 (10 µM), and under hypoxic conditions for 16 h at 37°C. Cell lysates were then prepared for Western blotting with the antibodies shown. (B) Role of the ODD of HIF-1α in the 1, 9 PA-induced downregulation of HIF-1α. A431 cells were transiently transfected with the HIF-1α-ΔODD construct or a control vector for 48 h and were then either untreated or treated with the indicated concentrations of 1, 9 PA for 1 h at 37°C. Cell lysates were then prepared for Western blotting with the antibodies shown. (C) Resistance of A431/HIF-1α-ΔODD cells to the 1, 9 PA-induced downregulation of HIF-1α. A431 cells stably expressing the HIF-1α-ΔODD construct were treated as described in (A). Cell lysates were then prepared for Western blotting with the antibodies shown.