FIGURE 3.

A, effect of hypoxia on cell cycle regulatory genes. For MCF-7 clones (vector (Vec), Trx, or dnTrx), cells were exposed to normoxia or hypoxia (1% O₂ + 5% CO₂ + 94% N₂) for 24 h. Cells were harvested, and micro-array analysis was performed as described previously (44). Top panel, vector, Trx, or dnTrx cells exposed to hypoxia; bottom panel, vector, Trx, or dnTrx cells exposed to normoxia. B, effect of hypoxia on p21 expression in MCF-7 cells. MCF-7-vector, MCF-7-Trx, or MCF-7 dnTrx was exposed to 1% oxygen for 24 h, followed by Western analysis of p21 in the cellular lysates as described under “Experimental Procedures.” C, HCT16-vector, HCT116-Trx, or HCT116-dnTrx cells were exposed to 0.2% oxygen for 24 or 48 h, and p21 Western analysis was performed on cellular lysates.