Fig. 4. Ectopic c-Rel expression in the Hs578TR cell population. Cultures of Hs578T cells in exponential growth were transfected with 22.5 µg of the murine c-Rel expression vector pSPORT-c-Rel and 2.5 µg of pSV2neo DNA. G418-resistant stable transfectants were isolated. In A, parental Hs578T and Hs578TR cells were plated at 20 and 40% confluence, and treated with 2 ng/ml TGF-ß1 or BSA as control for 24 and 48 h, respectively. The effects of TGF-ß1 on growth were measured by MTS assay. Cell numbers for TGF-ß1-treated cells are given as percent values relative to BSA-treated control cells. B, transfected Hs578TR (578TR) and parental Hs578T (578T) cells were plated at 40% confluence and treated with 2 ng/ml TGF-ß1 for 24 and 48 h. Nuclear extracts were isolated and subjected to EMSA using the URE NF-B oligonucleotide as probe. *, a nonspecific band that did not change with TGF-ß1 treatment.