FIGURE 8.

TPSF does not alter the level of ERα mRNA. A, shown is a Western blot of HeLa-ER cell extract. HeLa cells stably transfected to express functional wild-type ERα (76) were maintained in MEM + 10% FBS. Four days before, the cells were plated in 6-well plates at 50,000 cells/well in MEM + 10% 1× CD-FBS. The medium was changed after 2 days and on day 4 replaced with fresh medium containing 10 nm E₂ in DMSO or DMSO and the indicated concentration of TPSF. After 24 h, the cells were harvested, and extracts were prepared as described under “Experimental Procedures.” B, effect of TPSF on ERα mRNA levels in MCF-7 cells. Cells were maintained 4 days in MEM + 5% 1× CD-FBS as described under “Experimental Procedures.” Then cells were then maintained for 24 h in medium containing 10 nm E₂ in DMSO or DMSO with or without 10 μm TPSF and ER mRNA levels determined by qRT-PCR as described under “Experimental Procedures.” Data were the average of three experiments ±S.E.