Fig. 1. TGFß1-mediated transition of fibroblasts to myofibroblasts. (A) Subconfluent HDFs were cultured in control conditioned medium (CM^HDF), in co-culture with SCL-1 tumor cells (co-culture^HDF,SCL), treated with 10 ng/ml rTGFß1 in CM^HDF (CM^HDF,TGF), treated with conditioned medium of SCL-1 cells (CM^SCL) or treated with CM^SCL containing 5.0 µg TGFß1-neutralizing antibody (CM^{SCL,anti TGF}) for different time periods and then immunostained for SMA. Representative images are shown. Dotted line highlights the tumor cell cluster, the arrows indicate the nuclei of the tumor cells. Bar, 20 µm. (B) Subconfluent HDFs were treated with 10 ng rTGFß1/ml CM^HDF for 24 hours. The level of SMA protein was determined by western blot. The densitometric values represent the fold increase over control, which was set at 1.0. The data represent means ± s.e.m. of three independent experiments.