Effects of c‐Ski on in vitro proliferation of OCUM‐2MLN cells and the expression of p21, c‐myc, and growth arrest and DNA‐damage‐inducible 45β (GADD45β). (a) Proliferation of 2MLN‐green fluorescent protein (GFP) and 2MLN‐c‐Ski cells was compared by tetrazolium‐based colorimetric assay using 4‐[3‐(2‐methoxy‐4‐nitrophenyl)‐2‐(4‐nitrophenyl)‐2H‐5‐tetrazolio]‐1,3‐benzene disulfonate sodium salt (WST‐8) assay. Relative cell growth rate was quantified 3 days after seeding. Results are the mean ± SE of triplicate determinations. (b) 2MLN‐GFP and 2MLN‐c‐Ski cells were treated with or without transforming growth factor (TGF)‐β1 (1 ng/mL) for 24 h. Total RNA was extracted, and levels of expression of p21 (right), c‐myc (middle), and GADD45β (left) were examined by quantitative real‐time RT‐PCR analysis. Each value is normalized to the expression of hypoxanthine phosphoribosyltransferase 1 and represents the mean of triplicate determination.