Effects of hypoxia on LR11 mRNA levels and on sLR11 production by U937 cells.
A, LR11 mRNA expression in U937 cells after incubation under normoxic or hypoxic conditions for 3, 6, and 24 h was analyzed by quantitative PCR as described under “Experimental Procedures.” mRNA levels are represented as -fold increase of those at 0 h. Data are presented as mean ± S.D. (error bars; n = 3). *, p < 0.05; ns, not significant. B, after incubation under normoxic or hypoxic conditions for 6, 24, and 48 h, LR11 expression levels in U937 cells were analyzed by immunoblot analysis. The LR11-specific signals at 250 kDa were quantified using the Image Lab software. The blot shown is representative of three independent experiments. Data are presented as mean ± S.D. (n = 3). *, p < 0.05; ns, not significant. C, the concentrations of sLR11 in conditioned media of U937 cells incubated under normoxic or hypoxic condition for 48 h were determined by ELISA as described under “Experimental Procedures.” Data are presented as mean ± S.D. (n = 3). *, p < 0.05.