Fig. 1
SGK1 expression increases under hypoxia and regulates fatty acid uptake. NCI-H460 cells were exposed to acute (24 h 0.2 % O2) or chronic cycling hypoxia (25 cycles of severe hypoxia (48 h, 0.1 % O2) and re-oxygenation (20 % O2)). a The expression of SGK1 in NCI-H460 cells was determined using qRT-PCR analysis. Anoxia-tolerant cells displayed a significant increase in the expression of SGK1 compared to oxic control cells under normoxia. Both cell lines showed a pronounced up-regulation of SGK1 mRNA in severe hypoxia. b Western blot analysis of SGK1 protein expression. Upper panel shows representative Western blots of SGK1 and calnexin expression levels. Lower panel shows densitometric evaluation of SGK1 levels normalized to calnexin expression under the respective conditions. SGK1 protein levels were significantly increased in anoxia-tolerant cells compared to oxic control cells in normoxia as well as in response to severe hypoxia in both cell lines. c The impact of SGK1 inhibition by GSK650394 (40 μM for 24 h) on the uptake of FA was quantified under normoxic and severely hypoxic conditions in parental and anoxia-tolerant NCI-H460 cells by using the fluorescent FA analogue C1-BODIPY® 500/510 C12. SGK1-inhibition by GSK650394 did not significantly alter FA-uptake in normoxia, but significantly decreased the uptake of FA in severe hypoxia in both cell lines. Data show representative Western blots or mean values ± SD are shown, n = 3. (* p ≤ 0.05, ** p < 0.01; unpaired students t-test)