Triplicate experiments were Ro 61-8048 cost performed independently. Western blottings Western blottings using rabbit anti-human Bcl-2 antibody (#2876, Cell Signalling Technology)

and rabbit anti-human Bcl-xL antibody (556361, BD Biosciences) were performed according to standard protocols. Chemiluminescent detection was performed and images were captured by the FUJIFILM LAS-3000 system (Fujifilm, Tokyo, Japan). Extraction of RNA and RT –PCR Total RNA was extracted using TRIzol reagent (Invitrogen) according to the manufacturers’ PSI-7977 recommendations. RT-PCR(Reverse-Transcription PCR) was used to compare the relative mRNA expression of Bcl-2 and Bcl-xL in breast cancer cell lines. The primer sequences used were: Bcl-2, sense, 5′- GTGAACTGGGGGAGGATTGT-3′ and antisense, 5′- GGAGAAATCAAACAGAGGCC-3′ and Bcl-xL, sense, 5′-CCCAGAAAGGATACAGCTGG-3′ and antisense, 5′- GCGATCCGACTCACCAATAC-3′. Thirty-two cycles of PCR were performed using the program of 30 s at 94°C, 30 s at 56°C and 1min at 72°C. The PCR products were electrophoresed on 2% agarose gel and imaged using a ChemiImag 5500 Imaging System (Alpha Innotech, San Leandro, CA, USA). Apoptosis assay MDA-MB-231 and MDA-MB-231R cells (1 × 106) were plated in 10 mm dishes for each data point. Following incubation overnight

at 37°C, the cells were treated with ABT-737 (1 μM, 24 hours) and irradiated with 4 or 12 Gy. After 24 h, apoptotic analyses were performed by flow cytometry, as described previously [18], using a FACS Calibur system (Becton Dickinson Biosciences, San Diego, CA) with ModFit Belnacasan price LT™ software (Verity Software House, Inc.,

Topsham, ME). The apoptotic cells were analyzed by using quadrant statistics on the propidium iodide-negative and Annexin V-positive cells. Caspase-3 colorimetric assay The cells were collected and washed with phosphate-buffer saline (PBS, pH 7.2). After centrifugation, the caspase 3 colorimetric assays were performed according to the manufacturer’s specifications (ab39401, Abcam) using a Sunrise Microplate Reader(Tecan US, Inc.,Charlotte, NC). Cell viability Cell viability was evaluated using Cell Counting Kit-8 (CCK-8; either Dojindo Molecular Technologies Inc., Gaithersburg, MD) assay. The cells were plated in 96-well plates at 1 × 104 cells/well with media only, media with ABT-737 (1 μM) or DMSO, which were changed with media 24 hours later. To evaluate cell viability, 10 μl of CCK-8 was added per well, and the cells were incubated for an additional 4 hours, Following the incubation, the absorbance at 450 nm was recorded using a 96-well plate reader (Sunrise Microplate Reader, Tecan US, Inc.,Charlotte, NC). Animal experiments The animals used in this study were 4 to 6-week-old athymic female BALB/c nu/nu mice which were provided by the Shanghai Institute of Materia Medica, Chinese Academy of Science. MDA-MB-231R cells (106) were implanted into the mammary fat pad.