FIGURE 2.

KLF2 regulates hypoxia-mediated gene induction. A, effect of KLF2 on IL-8 induction by hypoxia. HUVECs infected with control (Ad-GFP) or KLF2 (Ad-K2) virus were exposed to normoxia (21% O₂) or hypoxia (1% O₂) for 24 h. Cells and culture media were harvested and followed by Northern blot analysis and ELISA (n = 3), respectively (top left and top right panels). HUVECs were transfected with siRNA targeting human KLF2 (siK2) or nonspecific siRNA (NS). 48 h later, the cells were exposed to normoxia or hypoxia for an additional 24 h (bottom left and bottom right panels). The cells and supernatants were collected and followed by Northern blot and ELISA (n = 3), respectively. Representative Northern blots are shown of three independent experiments. B, effect of KLF2 on angiopoietin-2 secretion by hypoxia. HUVECs were treated as described above, and culture media were subjected to ELISA (n = 6). C, effect of KLF2 on VEGF secretion in response to hypoxia. HUVECs infected with indicated virus or transfected with indicated siRNA were exposed to hypoxia for 6 h. The supernatants were collected, and VEGF secretion levels were determined by ELISA (n = 6). D, effect of KLF2 on prepro-adrenomedullin mRNA expression. HUVECs infected with indicated virus or transfected with indicated siRNA were exposed to hypoxia for 24 h. The cells were harvested, and RNA was isolated followed by real time PCR (n = 3). E, effect of KLF2 on GLUT1 mRNA expression during hypoxia. HUVECs infected with indicated virus or transfected with indicated siRNA were exposed to hypoxia for 24 h. GLUT1 mRNA levels were assessed by real time PCR (n = 3). *, p < 0.01.