FIG. 1.
Inducible expression of SRC-3 in LNCaP stable cell lines. (A) Diagram of the mifepristone-inducible gene expression system. (B) Western blot of different LNCaP stable clones in the presence and absence of mifepristone treatment. Note that SRC-3 expression was induced in clones 6, 9, 12, 24, and 48 after mifepristone treatment (10−8 M) for 24 h, while no induced SRC-3 expression was seen in clones 11, 16, and the control parental cell line. c, control. Similar induction was also shown with a HA antibody, since exogenously transfected SRC-3 is HA tagged. (C) Time course of SRC-3 induction shown by Western blots (clone 12). SRC-3 expression was induced as early as 2 h upon mifepristone treatment and remained at elevated levels for at least 24 h in the stable clones; (D) Androgen-independent induction of SRC-3 shown by Western blotting using a HA antibody (clone 48). Mifepristone (10−8 M) and 2 nM R1881 were used to treat cells for 24 h under stripped serum culture conditions. Similar results were obtained from other stable clones.