Figure 6
Higher levels of HIF1α under hypoxic conditions, and hyperoxia inhibited HIF1α expression. (A) An increased expression of HIF1α for U87 CD133−/CD15−/NESTIN− cells in 1%O2 conditions, which was predominately located in the cell cytoplasm; however, the HIF1α levels significantly decreased after exposure in 21%O2 or 95%O2 (P < 0.05, One-way ANOVA). (B) RT-qPCR indicated a 2-fold increase of HIF1α mRNA levels for U87 CD133−/CD15−/NESTIN− cells in the 1%O2 environment compared with normoxia; the expression of HIF1α was the lowest after hyperoxia exposure (P < 0.05, One-way ANOVA). (C) HIF1α expression was the highest in 1%O2 conditions, and the lowest levels of HIF1α were identified for U87 CD133−/CD15−/NESTIN− cells in 95%O2. (D) GL261 neurospheres formed in 1%O2 conditions highly expressed HIF1α. (E–G) An enhancement of HIF1α for newly formed U87 neurospheres in hypoxia was identified compared with normoxia and hyperoxia (* P < 0.05, Paired-samples T Test).
