Figure 1.

HPV-16 E7 abrogates hypoxia-induced G1 arrest. (a) RPE1 E7 cells were treated with hypoxia mimic drug DFO or CoCl₂ at different concentrations for 72 hours, cell viability was determined using CCK8 assay. Data from a representative of 3 experiments are shown. (b) RPE1 vector and RPE1 E7 cells were incubated in hypoxic chamber at 1% oxygen or with 200 μM DFO for 8 hours, respectively. Cells were stained by PI and examined by flow cytometry. Data from a representative of 4 experiments are shown (Upper panel) and are summarized (Lower panel). (c) RPE1 vector and E7 expressing cells were treated with 200 μM DFO for 6 hours and labeled with 20 nM BrdU for 2 additional hours. Cells were stained with anti-BrdU antibody, counterstained with 7-AAD, analyzed by flow cytometry. Data from a representative of 4 experiments are shown (Upper panel) and the percentage of BrdU-positive cells was gated. Data are summarized (Lower panel). Error bars reflected the standard error of the mean. *P < 0.05; **P < 0.01; ***P < 0.001.