FITC-labeled secondary antibody (diluted 1:100) was applied for 30 min at room temperature. (Burlingame, CA) and fluorescence-activated cell sorter (FACS) analysis (FacsScan; BD Biosciences). Briefly, cells were treated with 0, 40, 80, and 160 nmol/L of triptolide, and the cells were harvested at Irinotecan 24 h. After incubation, 100 L of treated cells was transferred to a 5-mL culture tube, and a solution made up of 5 L Annexin V-FITC plus 10 L PI was added. The tube was gently vortexed and incubated for 15 min at room temperature in the dark. Afterwards, 300 L binding buffer was added, and the cells were analyzed immediately by flow cytometry. The extent of early apoptosis was decided as the percentage of Annexin V+/PI? cells. Flow cytometric analysis was performed with a FACSCaliber using CellQuest software (BD, San Diego, CA, USA). Hoechst 33258 staining Nuclear fragmentation was visualized by Hoechst 33258 staining of apoptotic nuclei. Apoptotic cells were collected by centrifugation, washed with phosphate-buffered saline (PBS), and fixed in 4% paraformaldehyde for 20 min at room temperature. Subsequently, the cells were washed and resuspended in 20 L PBS before being deposited on polylysine-coated coverslips. The cells were then left to adhere to the cover slips for 30 min at room temperature, after which the cover slips were washed twice with PBS. The adhered cells were incubated with 0.1% Triton X-100 for 5 min at room temperature and rinsed with PBS three times. Cells were then treated with Hoechst 33258 for 30 min at 37 C , rinsed with PBS and mounted on slides with glycerol-PBS. The cells were viewed with an Olympus fluorescence microscope (Japan). Western Rabbit Polyclonal to CD97beta (Cleaved-Ser531) blotting Approximately 5106 cells were plated and incubated for 24 h prior to the addition of triptolide. U266 cells were collected following a 48-h incubation with triptolide (0, 40, 80, and 160 nmol/L, respectively), and PBMC from healthy donors were collected and cultured for 48 h. The cells were washed once with PBS, centrifuged, resuspended in a lysis buffer consisting of 50 mmol/L Tris (pH 7.4), 150 mmol/L NaCl, 1% Triton X-100, 1% sodium Irinotecan deoxycholate, 0.1% sodium dodecylsulfate (SDS), 1 mmol/L phenylmethylsulphonyl fluoride, and protease inhibitors and incubated for 1 h at 4 oC. Next, the cellular debris was pelleted by centrifugation at 15 000 round per min for 30 min, and the supernatant was collected. A BCA protein assay kit from Pierce Biotechnology was used to determine the protein concentration. Samples were separated on 8%?12% SDS-polyacrylamide gels and then transferred to nitrocellulose membranes using standard electroblotting procedures. After being blocked with 5% skim milk in Tris-buffered saline with 0.1% Tween-20 (TBS-T), membranes were incubated with the primary antibodies anti-H3K9me1 (1:2000; Upstate Biotechnology, Charlottesville, VA, USA), anti-RIZ1 (1:200; Santa Cruz, California, USA) and anti–actin (1:1000; Santa Cruz, California, USA) at 4 C overnight. Immunoblots were washed and then incubated with HRP-conjugated secondary antibodies (1:3000; Pierce Biotechnology, Rockford, IL, USA) for 1 h at room temperature and subsequently processed for enhanced chemiluminescence (ECL) detection using SuperSignal Substrate. Signals were detected by a chemiluminescence detection system (Bio-Rad, USA). Immunofluorescence with confocal microscopy After incubation with Irinotecan 40 mol/L triptolide for 24 h, cells were collected and fixed in 4% paraformaldehyde for 10 min. The suspensions were permeabilized with 0.25% Triton X-100 for 10 min, blocked with 3% bovine serum albumin for 30 min and then incubated with primary antibody against H3K9me1 (diluted 1:100; Upstate Biotechnology) overnight at 4 C. Then, the samples were exposed to TRITC-labeled secondary antibody (diluted 1:100) for 1 h and stained with Hoechst 33258 (10 g/mL) to visualize the DNA. Images were captured using an FV-500 confocal microscope (Olympus, Japan). RIZ1 protein analysis using flow cytometry Flow cytometry was performed to determine the expression of RIZ1 in U266 cells. A total of 1106 cells were collected and washed after 48 h culture, anti-RIZ1 antibody (dilution 1:100; Santa Cruz) was added, and the mixture was kept at 4 C overnight. Cells treated without primary antibody served as the unfavorable control group. FITC-labeled secondary antibody (diluted 1:100) was applied for 30 min at room temperature. Stained cells were analyzed on a flow cytometer. The mean fluorescence intensity (MFI) of the cells was determined by the CellQuest software program. The final MFI was calculated by subtracting Irinotecan the MFI of the unfavorable controls. Reverse transcription-polymerase chain reaction Total cellular RNA was extracted using Trizol reagent. Reverse transcription (RT)-polymerase chain reaction (PCR) was performed with the appropriate primers, following the protocol of the TOYOBO kit. A 20-L PCR reaction mixture was initially amplified. Primer pairs were all designed from.