By Down-regulating The Expression Of PGE2,Salinomycin Promotes The Apoptosis And Inhibits The Tumor Microspheres Of DU145 Cell Line

Objective:Observing the expression of PGE2 and its' down-stream receptors in DU145 cell line after treated with different concentrations of salinomycin,and detecting the the efficacy changes of salinomycin on the cells apoptosis and tumor microspheres of DU145 cells after adding different concentrations of exogenous PGE2,thus to provide some experimental evidences for the clinical use of salinomycin in the treatment of prostate cancer.Materials and methods:?1?Treated DU145 cells with 2.5?M?5.0?M?10.0?M?15.0?M salinomycin for 24 hours,set blank and DMSO groups as controls,then detected the expression of PGE2 by ELISA and the expression of PGE2 down-stream receptors EP₁,EP₂,EP₃ and EP₄ by Western-Blot.?2?DU145 cells were respectively treated with salinomycin combined with 0.5?M,1.0?M and 2.0?M exogenous PGE2,set blank,DMSO and 5.0?M salinomycin groups as controls.After cultured for 24 hours,we performed the AO-EB staining on these cells and observed the apoptosis condition under the fluorescence microscope.?3?DU145 cells were respectively treated salinomycin combined with 0.5?M,1.0?M and2.0?M exogenous PGE2,set blank,DMSO and 5.0?M salinomycin groups as controls,cultured these cells in serum-free medium which had removed growth factors and adhesion factors for about 7 days until the tumor microspheres were formed,then counted the tumor microspheres number in each group.Result:?1?The expression levels of PGE2 in blank group,DMSO group and 2.5?M,5.0?M,10.0?M,15.0?M salinomycin group respectively were 142.0±5.1 pg/ml,138.0±4.6pg/ml,118.0±3.9 pg/ml,87.0±2.7 pg/ml,52.0±4.2 pg/ml,42.0±2.8pg/ml.Compared with the blank group and the DMSO group,the expression of PGE2 in the salinomycin treatment groups were down-regulation,differences were statistically significant?p<0.05?.The higher the concentration of salinomycin was,the lower the expression of PGE2 was,differences were statistically significant?p<0.05?.There was no statistically difference on the expression of EP₁,EP₃,EP₄ in each group?p>0.05?,but the expression levels of EP₂ in salinomycin treated groups were lower than that in blank group and DMSO group,differences were statistically significant?p<0.05?.The higher the concentration of salinomycin was,the lower the EP₂ expression level was,differences between each group were statistically significant?p<0.05?.?2?The cells' apoptosis rates of blank group,DMSO group and5?M salinomycin group respectively were?12.0±3.0?%,?11.0±1.5?%and?84.2±4.0?%,the apoptosis rates of 5?M salinomycin group was significantly higher than that of blank group and DMSO group,differences were statistically significant?p<0.05?.The apoptotic rates of 5?M salinomycin combined with 0.5?M,1.0?M,2.0?M exogenous PGE2 groups were respectively?76.2±3.7?%,?33.8±3.8?%and?19.5±4.3?%.Compared with 5?M salinomycin group,the apoptosis rate of salinomycin combined with exogenous PGE2 groups were significantly lower,differences between each group were statistically significant?p<0.05?.?3?The average number of tumor microspheres per low-power field of blank group,DMSO group and 5?M salinomycin group respectively were 13.2±1.7,12.7±1.9,0.9±0.5,the tumor microspheres number of 5?M salinomycin group was significantly higher than that of blank group and DMSO group,differences were statistically significant?p<0.05?.The average number of tumor microspheres per low-power field of 5?M salinomycin combined with 0.5?M,1.0?M,2.0?M exogenous PGE2 groups were respectively 3.7±0.6,6.3±1.3,8.7±1.2,compared with 5?M salinomycin group,the tumor microspheres number of salinomycin combined with exogenous PGE2 groups were significantly lower,differences between each group were statistically significant?p<0.05?.Conclusion:?1?Salinomycin could down-regulate the expression of PGE2 and EP₂ in DU145 cell line.?2?Salinomycin may promote the apoptosis of DU145 cells by inhibiting the expression of PGE2.?3?Salinomycin may inhibits the microspheres forming by down-regulating the expression of PGE2.