A, Smad1, Smad5, and Smad8 were overexpressed using pLPCX retrovirus in LNCaP cells as shown by Western blot analysis. B, LNCaP-pLPCX-control, -Smads 1, 5 or 8 cells were treated with rapamycin (200 nmol/L) for 24 h and examined by Western blot analysis. C, Stably overexpressing LNCaP-Smads 1, 5, and/or 8 were subjected to Id1 promoter activity following treatment of cells with rapamycin (200 nmol/L) for 24 h prior to BMP4 (5 ng/ml) for 4 h. D, LNCaP-pLPCX-control or -Smad1,-Smad5, and/or -Smad8 stably overexpressing cells were treated with rapamycin (200 nmol/L) for 72 h prior to examining % viable adherent cells. Columns, average of triplicate determinants; bar, ±S.E and experiments were run in triplicate.