Figure 5

Follistatin blocks the growth arrest induced by activin A in LE6 cells. (A) LE6 cells were treated with activin A (200 ng/ml) in the presence or absence of the indicated doses of follistatin (25, 50, 100, 200, 400, 600 ng/ml). Cell proliferation was detected by CCK-8 assay. (B) LE6 cells were grown in LE media in the presence or absence of activin A (200 ng/ml), follistatin (400 ng/ml) or activin A (200 ng/ml) plus follistatin (400 ng/ml). DNA synthesis was detected by BrdU incorporation assay using FACS. (C) LE6 cells were treated with or without activin A (200 ng/ml), follistatin (400 ng/ml) or activin A (200 ng/ml) plus follistatin (400 ng/ml) for 30 min. Phosphorylated SMAD2/3 was detected by western-blot. (D) LE6 cells were treated with either media alone, activin A (200 ng/ml), follistatin (400 ng/ml) or activin(200 ng/ml) plus follistatin (400 ng/ml). Then phosphorylated Rb, cyclinD1, cyclinE, p21^WAF1/Cip1and p15^INK4B were analyzed by western-blot.