(A) MCF-7 cells were incubated for the indicated time (0, 6, 12, 24, 36 h) in
normoxic (21% O2) or hypoxic (1% O2) conditions. After
incubation, the media were analyzed for VEGF levels by ELISA assay, and the cell
number was counted. (B) MCF-7, Ad-LacZ-MCF-7 and Ad-NDRG2-MCF-7 cells
were incubated for the indicated time (24, 48 h) in normoxic or hypoxic conditions.
After incubation, the media were analyzed for VEGF levels by ELISA assay, and the cell
number was counted. The data are the mean ± standard deviation (SD) for three
independent experiments. Statistical significance was assessed with one-way ANOVA and
Student's t-test. * or ** indicates P<0.05 or
P<0.01, respectively, when compared with the normoxia or
Ad-LacZ-MCF-7 group. N, normoxia; H, hypoxia. (C) MCF-7, Ad-LacZ-MCF-7 and
Ad-NDRG2-MCF-7 cells were incubated under hypoxia for 0, 12, or 24
h. After incubation, the cells were analyzed by western blot assay. β-actin protein
levels were used as a loading control.