Figure 6

Measurement of lactate levels in the cell culture medium. The media from cell cultures were collected after transfection of the cells with HIF-1α siRNA vector or a HIF-1α expression plasmid and exposure to hypoxic conditions for 24 h. Lactate concentration was measured using a commercial kit (n = 5 in each group). $, P < 0.05 compared to normoxic mock transfected and HIF-1α siRNA; *, P < 0.05 compared to hypoxic HIF-1α siRNA and HIF-1α expression vector with HEPES; #, P < 0.05 compared to hypoxic HIF-1α expression vector with or without 2-DG. siRNA: A549 cells transfected HIF-1α siRNA vector, Mock: mock-transfected, HIF: A549 cells transfected with HIF-1α expression plasmid, HIF+2-DG: Cells transfected with HIF-1α expression plasmid and cultured with 2-DG, HIF+HEPES: Cells transfected with HIF-1α expression plasmid and cultured with medium containing HEPES.