Reversion of multi-drug resistance of gastric carcinoma cisplantin-resistant cell SCG7901/DDP by silencing caudal type homeobox 2

Abstract

Objective To investigate the effects of caudal type homeobox 2 (Cdx2) silence on reservion of multi-drug resistance of gastric carcinoma cisplantin-resistant cell SGC7901/DDP.Methods Gastric carcinoma cisplantin-resistant cells SCG7901/DDP in the logarithmic phase were cultured in the plate,and were divided into the experimental group [gastric carcinoma cells of SGC7901/DDP were infected with a silent Cdx2-recombinanted lentiviral vector (pLL-Cdx2-shRNA)],the negative control group (gastric carcinoma cells of SGC7901/DDP were infected with empty lentiviral vector) and the blank control group (gastric carcinoma cells of SGC7901/DDP were not treated).The protein and mRNA expressions of Cdx2 and apoptosis related genes like c-myc,cyclin D1 and survivin were detected by the Western blot and reverse-transcription PCR,respectively.The sensitivity of the cells in the 3 groups to adriamycin,5-fluorouracil and cisplatium were assessed by MTT.The pump-out rate of adriamycin,cell cycle distribution and apoptosis of the 3 groups were analyzed using flow cytometry.All measurement data were expressed with mean ± standard deviation.Comparison among multi-groups was done by one-way analysis of variance,and comparison between 2 groups was done by SNK-q test.The enumeration data were analyzed using the chi-square test.Results The relative protein expression levels of Cdx2,c-myc,cyclin D1 and survivin were 0.187 ± 0.060,0.086 ± 0.004,0.016 ± 0.005 and 0.276 ± 0.012 in the experimental group,0.535 ± 0.033,0.379 ± 0.006,0.141 ± 0.003 and 0.672 ± 0.009 in the negative control group,and 0.567 ± 0.014,0.354 ± 0.004,0.162 ± 0.008 and 0.517 ± 0.313 in the blank control group,respectively.The relative protein expression levels of Cdx2,c-myc,cyclin D1 and survivin in the experimental group were significantly lower than those in the negative control group and the blank control group (F =247.385,3.353,597.882,98.628,P ＜0.05).The relative mRNA expression levels of Cdx2,c-myc,cyclin D1 and survivin were 0.184 ± 0.010,0.212 ± 0.022,0.045 ± 0.009 and 0.401 ± 0.027 in the experimental group,0.894 ± 0.056,0.538 ± 0.021,0.163 ±0.009 and 0.824 ± 0.016 in the negative control group,and 0.837 ±0.049,0.545 ±0.032,0.157 ±0.010 and 0.782 ±0.056 in the blank control group,respectively.The relative mRNA expression levels of Cdx2,c-myc,cyclin D1 and survivin in the experimental group were significantly lower than those in the negative control group and the blank control group (F =243.776,161.793,138.523,118.426,P ＜ 0.05).The IC50 values detected by MTT of adriamycin,5-flurouracile and cisplatin to gastroc carcinoma cisplantin-resistant cell SCG7901/DDP were (0.12 ± 0.05) mg/L,(0.52 ± 0.13) mg/L and (0.82 ± 0.13) mg/L in the experimental group,(0.33 ± 0.08) mg/L,(4.10.± 1.25) mg/L and (2.81 ± 0.50) mg/L in the negative control group,(0.39 ±0.15)mg/L,(4.05 ± 1.44) mg/L and (3.28 ± 1.03) rng/L in the blank control group,respectively.The pump-out rates of adriamycin of the experimental group,negative control group,and the blank control group were0.21％,0.37％ and 0.35％.Compared with the negative control group and the blank control group,the IC50values of adriamycin,5-fluorouracil and cisplatin in the experimental group were significantly increased,and thepump-out rate of adriamycin was significantly decreased (F =8.101,13.854,15.159,x2 =7.106,P ＜ 0.05).The ratios of cells in the G0/G1 phase were 17.87％,34.71％ and 37.20％ in the experimental group,negative control group and the blank control group,respectively.Compared with the negative control group and blank control group,the ratio of cells in the G0/Gt was significantly decreased (x2=1.055,P ＜ 0.05).The ratio of cells in the G2/M phase in the experimental group was 11.93％,and the apoptosis rate was 31.13％,which were significantly higher than the negative group (0.26％,16.58％) and the blank control group (0.35％,13.18％) (x2=2.249,11.030,P ＜ 0.05).Conclusions Silent Cdx2 can effectively enhance the sensitivity of the SGC7901/DDP cells and the intracellular accumulation concentration of the drugs.Silent Cdx2 can also reverse the multidrug resistance of the SGC7901/DDP cells. Key words: Gastric neoplasms; Caudal type homeobox 2; Gastric carcinoma cisplantin-resistant cell SGC7901/DDP; Multi-drug resistance