Effect of AHSG depletion on TGF-β1 induced signaling in human SQ20B HNSCC sublines EV, AH50 and AH20. (A–D) Sublines, EV, AH50 and AH20, were seeded and then serum-starved for 48 h. Sublines were treated with 0, 10 or 100 ng/ml of human recombinant TGF-β1 in HBSS for 15 min at 37°C. Total cell lysates were prepared and equal amounts of protein used for analyses by immunoblotting. (A) Phosphorylation of SMAD2/3 was examined by immunoblot using antibody to phosphorylated SMAD 2/3 and was compared to immunoblot of total SMAD 2/3. (B) Densitometric quanitation of the activation of SMAD2/was performed following treatment with indicated TGF-β1. Phosphorylation of SMAD2/3 was normalized to total SMAD2/3. (C) The sublines EV, AH50 and AH20 were treated and harvested as above. Phosphorylation of ERK was examined by immunoblot using antibody to phosphorylated ERK; detection of total ERK was used for normalization. (D) Densitometric analysis was used to normalize pERK bands to total ERK.