The mRNA levels of GCS and MDR1 were measured with RT-PCR. The Selleckchem Veliparib following specific oligonucleotide primers were designed respectively for mdr1 (mdr1-F:5′- TGGTGGTGGGAACTT TGG-3′ and mdr1-R:5′-CCTATCTCCTGTCGCATT-3′),

GCS (GCS-F:5′-CACCCGATTACACCTCAA – 3′ and GCS-R: 5′-CCGTGAACC AAGCCTACT-3′), β-actin (β-actin-F:5′-TGACGTGGACATC CGCAAAG – 3′, and β-actin-R: 5′-CTGGAA GGTGGACAGCGAGG – 3′). PCR cycles were adjusted to have linear amplification for all the targets. Each RT-PCR reaction was repeated three times. The semiquantitative analysis of GCS mRNA and MDR1 mRNA levels Selleckchem Ro 61-8048 was measured with Syngene Gel Imaging System and analysis software (Syngene Company). Western blotting analysis of P-gp, Caspase-3 and GCS protein HCT-8, HCT-8/VCR, HCT-8/VCR-sh-mock and HCT-8/VCR-sh-GCS were harvested using RIPA cell lysis buffer (Biotech Corporation). The protein concentrations were measured by using a bicinchoninic acid (BCA) protein assay kit. Equal aliquots of total detergent-soluble proteins (50 μg) were resolved to 5-10% gradient SDS-PAGE. The transferred PVDF membrane were blocked with 5% fat-free milk in TBST at room temperature for 1 h and then incubated with primary antibodies (anti-P-gp antibody, C-19,

anti-GCS antibody, anti-caspase-3 or anti-β-actin antibody; 1:1000 dilution) at 4°C overnight. The protein was detected by using horseradish peroxidase

(HRP) and enzyme-linked chemiluminescence (ECL) plus substrate (GE Healthcare, Piscataway, NJ) Anti-human P-gp antibody (C-19) CX-5461 order and GCS antibody (H-300) and anti-caspase-3 antibody were purchased from Santa Cruz Corporation. The protein levels of P-gp, Caspase-3 and GCS were represented by the ratios of optical densities in PRKD3 their bands normalized against β-actin. Cytotoxicity assay In 96 well plates, cells were seeded in 100 μl PRMI-1640 medium supplemented with 10% FBS at 5 × 103 cells/well. Then chemotherapeutic agents were added in normal growth medium supplemented with FBS. After 48 h incubation, 10 μl Cell Counting Kit-8 (CCK-8) was added and culture was continued for 1 h in humidified atmosphere containing 5% CO2. Absorbances at 450 nm were measured by Microplate Reader (Bio-Tech Company). The relative drug resistance folds were analyzed by compared with IC50. Flow cytometry To measure the apoptosis rate of the cells, we chose the AnnexinV-FITC Apoptosis Detection Kit. The cells were washed 2 times by 4°CPBS, and diluted with 400 μl AnnexinV binding liquid, then added 5 μl Annexin V-FITC at 4°C for 15 min without light, and then added 10 μl PI at 4°C for 5 min without light. The cells were measure with flow cytometry within 1 h. Statistical analysis All of the data were presented as the mean ± SD, and analyzed with one-way ANOVA by SPSS16.0 software package.