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and J.H.H. extract (Gibco-Invitrogen). RNA interference Cdc6-specific siRNA with the following sequence: Cdc6_1: 5?-AAC UUC CCA CCU UAU ACC AGA-3?39, Cdc6_2: 5?-AAG AAU CUG CAU GUG UGA GAC-3?40 and Cdc6_3: 5?-CCA AGA AGG AGC ACA AGA U-3?41 were synthesized by GenePharma (Shanghai, China). Cells were Rabbit Polyclonal to FOXC1/2 transfected with the siRNA using Lipofectamine RNAiMAX transfection reagents according to the manufacturers instructions (Invitrogen, Carlsbad, CA, USA). Cell proliferation and colony formation assays PANC-1 cells were seeded in 12-well plates at a density of 2??104 cells per well. After siRNA transfection, cell proliferation was monitored every 24?h for 7?days using MTT (Sigma-Aldrich, Saint Louis, MO, USA) assay. Briefly, 50?L of prepared MTT answer was added to each well at the desired time point and incubated at 37?C for 4?h. The media was carefully removed and the cells were solubilized in 500 L of dimethyl sulfoxide (DMSO). Plates were go through spectrophotometrically at a wavelength of 570?nm. For the colony formation assay, 1??103 PANC-1 cells were seeded in a six-well plate and transfected with siRNA. After 2?weeks, the colonies were fixed with methanol, stained with 0.1% crystal violet (Sigma-Aldrich), and counted. Circulation cytometric analysis of the cell cycle and apoptosis To analyze the cell cycle, cells were collected, fixed with 80% chilly ethanol, and managed at 4?C overnight. The cells were then treated with 50?g/mL RNAse A, stained with 50?g/mL PI, and analyzed by circulation cytometry (BD Biosciences, San Jose, CA, USA). To assess apoptosis, the cells were double stained with an FITC Annexin V apoptosis detection kit (BD Biosciences) and analyzed according to the manufacturers instructions. Western blotting Cells were lysed with radioimmunoprecipitation assay (RIPA) buffer (Cell Signaling Technology Inc., Danvers, MA, USA), a protease inhibitor cocktail (Sigma-Aldrich), and phenylmethylsulfonyl fluoride (PMSF, Cell Signaling Technology). Protein concentration was measured using the bicinchoninic acid (BCA) protein assay reagent (Pierce-Thermo scientific, Rockford, IL, USA). Equivalent amounts of protein from each cell lysate were separated on sodium dodecyl sulfate (SDS) polyacrylamide gels, transferred onto nitrocellulose (NE) membranes, and reacted with antibodies against p-histone H3 ser10 (Thermo Fisher Scientific, Waltham, MA, USA), cyclin A2 (Cell Signaling Technology), caspase-3 (Cell Signaling Technology), or caspase-9 (Cell Signaling Technology). The membranes were then washed with TBST (Tris-buffered saline, 0.1% Tween 20), incubated with HRP-conjugated anti-mouse IgG (The Jackson Laboratory, Bar Harbor, ME, USA) or anti-rabbit IgG (Cell Signaling Technology) secondary antibodies, and the target proteins were detected with ECL western blotting detection reagents (Amersham-GE Healthcare Life Sciences, Malborough, MA, USA). Total protein loading amounts and intensity were quantified using -actin (Cell Signaling Technology) as the loading control. Immunofluorescence microscopy PANC-1 cells were cultured in a Lab-Tek chamber slide 5-Hydroxydopamine hydrochloride (Nalge Nunc International, Rochester, NY, USA) at a density of 20,000 cells/well. After 48?h, cells were fixed with 4% paraformaldehyde in phosphate buffered saline (PBS) for 15?min. After being permeabilized with 0.5% Triton X-100 in PBS for 10?min, the cells were blocked with 1% BSA in PBS and incubated with main antibodies overnight at 4?C. Main antibodies used in these studies were anti-pericentrin (Abcam, Cambridge, UK), anti–tubulin (Abcam), human anti-CREST (Immuno Vision Inc., Springdale, AR, USA) and anti-cleaved caspase-3 (1:400, Cell Signaling Technology). The cells were then washed three times with 5-Hydroxydopamine hydrochloride PBS, and incubated with the indicated secondary antibody for 2?h at 25?C. Secondary antibodies were goat Alexa Fluor 568 (Invitrogen), goat Alexa Fluor 488 (Abcam), and goat anti-Human IgG-FITC (Invitrogen). Nuclei were counterstained with DAPI and mounted with ProLong Gold Antifade (Invitrogen). Images were captured using a ZEISS LSM 710 confocal microscope and processed using ZEN software 5-Hydroxydopamine hydrochloride (ZEISS International, Oberkochen, DE). Chromosome spreading assay Cells were treated with colcemid (0.1?g/mL) for 4?h and then harvested. After treatment with 0.075?M KCl and incubation at 37?C, the cells were fixed with a dropwise application of a freshly-prepared methanol/acetic acid (3:1) solution and placed on glass slides. Slides were dried at room temperature, stained with DAPI (100?ng/mL), and mounted with ProLong.