Bcl-2 upregulation by GP88 in AC1 cells. A: The ability of letrozole to down regulate bcl-2 expression was examined for AC1. AC1 cells were plated at 1.5 × 105 cells/well in 6-well plate and incubated in PRF medium with 5% ChX-FBS. The next day, the medium was removed and fresh PRF-5%ChX-FBS medium was added with the indicated treatments 25 nM androstenedione (AD) or AD with 200 nM letrozole (ADL) alone or in the presence of GP88 (150 ng/ml and 300 ng/ml). After 48 hours, total RNA was extracted with Trizol™. Bcl-2 mRNA expression was determined by RT-PCR and examined by agarose gel electrophoresis and staining by ethidium bromide as described in the method section. GAPDH mRNA expression was examined as internal control for equal loading. B: Bcl-2 and GAPDH band intensities of triplicate experiments were determined by densitometry scanning using a UVP gel densitometer. Relative average intensity of bcl-2 bands from the triplicate experiments in each experimental group were then normalized using GAPDH as an internal standard and expressed as bars ± SD, p < 0.05.