Smad3 and HIF-1α are independently capable of inducing TGF-β2 mRNA in response to hypoxia.
Smad4-deficient MDA-MB-468 and Smad4-expressing A549 were transiently transfected with indicated Smad and HIF-1α expression vectors and RSV–β-gal by electroporation. Each transfection was divided into 2 plates and exposed to either 20% or 1% O2for 18 hours. TGF-β2 mRNA levels were determined by real-time RT-PCR analysis, using TGF-β2–specific TaqMan primers and probe. Amount of mRNA in each group is normalized to GAPDH. Results are presented as fold change in TGF-β2 mRNA in normoxic (■) or hypoxic (▪) conditions relative to the levels observed in cell line A549 under basal normoxic conditions. Bars represent mean ±SD from 3 independent experiments (*P < .05 for hypoxic and **P < .05 for normoxic results).
