The effects of KRG treatment on cell viability were determined by MTT assays to assess mitochondrial function [22]. SK-N-SH cells were seeded in 96 well-plate and incubated with KRG (1mg/mL) for 48 h and subsequently treated with 0.5mM H2O2 for 2 h. Next, RPMI medium containing MTT dye (2 mg/mL) was added to cell cultures, and plates were incubated

for 1 h at 37°C with 5% CO2. Supernatants were selleck chemicals llc then removed, 150 μl of dimethyl sulfoxide was added to wells for 15 min to solubilize liberated formazan, and absorbance was read at 540 nm with a plate reader. Experiments were performed in triplicate. Cells were washed with phosphate-buffered saline (PBS), harvested, and collected by centrifugation. Cell pellets were lysed in radioimmunoprecipitation assay buffer containing 50mM Tris-Cl pH 7.4, 0.5% sodium deoxycholate, 0.1% sodium dodecyl sulfate, 150mM NaCl, 1mM ethylenediaminetetra-acetic acid, 1mM phenylmethylsulfonyl fluoride, and 1× protease inhibitor cocktail. Protein concentrations in samples were determined by Bradford assays, and 30–40 μg of protein from each sample were resolved on 12.5% sodium dodecyl sulfate polyacrylamide gel electrophoresis gels. Samples were transferred to polyvinylidene difluoride membranes (Millipore, Billerica, MA, USA), which were blocked on a shaker at room temperature

for 2–3 h check details in Tris-buffered saline with 0.1% Tween-20 (T-TBS) containing 7% skim milk. Membranes were then washed three times with T-TBS and incubated overnight with primary antibodies at 4°C. Primary antibodies recognizing human ER-β (sc-53494), bcl-2 (sc-7382), p-p53 (sc-101762), PI3K-p110 (sc-7189), Akt (sc-8312), and p-Akt (sc-7985-R) were purchased from Santa Cruz Biotechnology, Inc. Primary antibodies recognizing β-actin and anti-caspase-3 were obtained from Sigma–Aldrich and Cell Signaling Technology (Beverley, MA, USA), respectively. Subsequently, membranes were washed 4 times with T-TBS and incubated for 1 h at room temperature with horseradish peroxidase-conjugated anti-rabbit or anti-mouse

secondary antibodies (Sigma–Aldrich). Membranes were washed in T-TBS and proteins of interest were detected using the Power Optic-ECL Western blotting Detection reagent (Animal Genetics Inc., isothipendyl Gyeonggi-do, Korea). Statistical differences between group medians from three independent experiments were analyzed by analysis of variance. Differences were considered statistically significant in cases where p < 0.05. Previously, we showed that ER-β expression is inhibited by oxidative stress and upregulated following exposure to KRG [17]. ER-β is an upstream regulator of apoptosis [23] and [24]. Here, we examined whether KRG inhibits oxidative stress-induced apoptosis via ER-β upregulation (Fig. 1). ER-β expression was blocked by transfecting SK-N-SH cells with siER-β prior to treating cells with 0.5mM H2O2 to cause oxidative stress.