Abstract:
Objective: To investigate the effects of caudal type homeobox 2 (Cdx2) silence on reservion of multidrug resistance of gastric carcinoma cisplantinresistant cell SGC7901/DDP.
Methods: Gastric carcinoma cisplantinresistant 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 Cdx2recombinanted lentiviral vector (pLLCdx2shRNA)], 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 cmyc, cyclin D1 and survivin were detected by the Western blot and reversetranscription PCR, respectively. The sensitivity of the cells in the 3 groups to adriamycin, 5fluorouracil and cisplatium were assessed by MTT. The pumpout 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 multigroups was done by oneway analysis of variance, and comparison between 2 groups was done by SNKq test. The enumeration data were analyzed using the chisquare test.
Results: The relative protein expression levels of Cdx2, cmyc, 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, cmyc, 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, cmyc, 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, cmyc, 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 IC 50 values detected by MTT of adriamycin, 5flurouracile and cisplatin to gastroc carcinoma cisplantinresistant 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 experi mental 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)mg/L in the blank control group, respectively. The pumpout rates of adriamycin of the experimental group, negative control group, and the blank control group were 0.21%, 0.37% and 0.35%. Compared with the negative control group and the blank control group, the IC 50 values of adriamycin, 5fluorouracil and cisplatin in the experimental group were significantly increased, and the pumpout rate of adriamycin was significantly decreased (F=8.101, 13.854, 15.159, χ2=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.