Hoechst staining assay Cells were cultured on 6-well tissue culture plates to confluence and treated with or without DDP for another 12 h. Then, Hoechst 33342 (Sigma, USA) was added to the culture medium of living cells; changes in nuclear morphology were detected Selleckchem ICG-001 by fluorescence microscopy using a filter for Hoechst 33342 (365 nm). The percentages of Hoechst-positive nuclei per optical field (at least 50 fields) were counted. Caspase-3 activity The activity of Caspase-3

was measured using Caspase-3 Colorimetric Assay Kit (Nanjing Keygen Biotech. Co., Ltd) following the manufacturer’s instruction. In brief, cells were seeded in the 6-wells and were cultured for 24 h. Then, the cells were administered with or without DDP for another 12 h and harvested, resuspended in 50 μL of lysis buffer and incubated on ice for 30 min, and cellular debris was pelleted. The lysates (50 μL) were transferred to 96-well plates. The lysates were AZD6244 clinical trial added to 50 μL 2.0 × Reaction Buffer along with 5 μL Caspase-3 Substrate and incubated for 4 h at 37°C, 5% CO2 incubator. The activities were quantified spectrophotometrically at a wavelength of 405 nm. Terminal Transferase dUTP Nick End Labeling (TUNEL) Assay Tissues were plated on polylysine-coated slides, fixed with

4% paraformaldehyde in 0.1 M phosphate-buffered saline (PBS) for 1 h at 25°C, rinsed with 0.1 M PBS, pH 7.4, and permeabilized with 1% Triton X-100 in 0.01 M citrate buffer (pH 6.0). DNA fragmentation was detected using TUNEL Apoptosis Detection Kit (Nanjing KeyGen, China), SB-3CT which specifically labeled 3′-hydroxyl termini of DNA strand breaks using fluorescein isothiocyanate (FITC)-conjugated dUTP. DNA was also labeled with FITC DNA-binding dye for 5 min. FITC labels were observed with a fluorescence microscope. The percentage of apoptotic cells was calculated as the number of apoptotic cells per number of total cells × 100%. Animal experiment All experimental

procedures involving animals were in accordance with the Guide for the Care and Use of Laboratory Animals and were performed TGF-beta/Smad inhibitor according to the institutional ethical guidelines for animal experiment. Each aliquot of mock or stably transfected A549 cells were injected into the flanks of BALB/c nude mice (Nu/Nu, female, 4-6 weeks old) which were purchased from the Experimental Animal Centre of Nanjing Medical University and maintained under pathogen-free conditions (n = 8/group). One day after tumor cell implantation, mice were treated with CDDP (3.0 mg/kg body weight; i.p., thrice/week), Tumor volume was followed up for 4 weeks and measured once weekly. The tumor volume formed was calculated by the following formula: V = 0.4 × D × d2 (V, volume; D, longitudinal diameter; d, latitudinal diameter). All mice were killed and s.c. tumors were resected and fixed in 10% PBS. TUNEL staining assay was performed on 5 μm sections of the excised tumors. The number of apoptotic cells in five random high-power fields was counted.