HIF-1α in epithelial adenosine kinase (AK) repression. (A) Characterization of CaCo-2 intestinal epithelia expressing oxygen-stable HIF-1α (CaCo-ΔODD) by Western blot analysis. (B) Confluent monolayers of control (CaCo-WT, ■) or oxygen-stable HIF-1α expressing (CaCo-ΔODD, ) cell lines were exposed over indicated time periods to hypoxia (2% oxygen). Total RNA was isolated and AK or VEGF transcript was determined by real-time RT-PCR. Results are derived from 3 experiments (*P < .05 indicates differences between normoxia and hypoxia; #P < .05 between different cell types). (C) Western blot analysis of AK protein during similar conditions. (D) Characterization of CaCo-2 intestinal epithelia with psiRNA repression of HIF-1α (HIF1α^−/−) or control transfected cells (Scr) by Western blot analysis. (E) Confluent monolayers of control (CaCo-Scr, ■) or HIF-1α–silenced CaCo-2 cells (CaCo-HIF1α) were exposed over indicated time periods to hypoxia (2% oxygen) and AK or VEGF transcript was determined by real-time RT-PCR (*P < .05 indicates differences between normoxia and hypoxia). (F) Western blot analysis of AK protein during similar conditions.