The Reversal Of MRP1 Expression Affected By Low-frequency And Low-intensity Ultrasound And Curcumin Mediated By VEGF In Brain Glioma

Objective:The aim of this study was to explore the inhibition rate of curcumin and low-frequency and low-intensity ultrasound(LFLIU)on C6 and U87 cell,explore the expression of vascular epithelial growth factor(VEGF)and multidrug resistance protein1(MRP1),and observe the interactions of VEGF and MRP1 in glioma.Methods:1.Treated by different concentrations of curcumin(5μmol/L,10μmol/L,15μmol/L and 20μmol/L)respectively on human brain glioma U87 cells and rat brain glioma C6 cells for 24h,the inhibition rate of C6 and U87 cells was measured by CCK-8.2.Treated by different intensity of LFLIU(3m W/cm~2,50.4m W/cm~2,83.4m W/cm~2,142m W/cm~2,290m W/cm~2and 474m W/cm~2)respectively on C6 and U87 cells for 60s,the inhibit rate was measured by CCK-8.3.The dose of curcumin,10μmol/L or 15μmol/L,and the intensity of ultrasound,142m W/cm~2,was selected as the parameters for the following study.The inhibition rate of U87 and C6 cells was measured by CCK-8.4.The morphological changes of the U87 cells and C6 cells were observed by microscope,and the expression of Survivin was detected by Western blot.5.The m RNA expression of VEGF and MRP1 was detected by Real-time PCR,and Western blot was used to detect the protein expression of VEGF and MRP1 in the glioma cells.6.U87 and C6 cells were pretreated with the recombinant human vascular epithelial growth factor,or LY294002,an inhibitor of PI3K/Akt signaling pathway.Protein expressions of MRP1 was assessed by western blot.Results:1.Curcumin significantly inhibited C6 and U87 cell growth in a dose-dependent manner.When the concentration of curcumin is higher than 10μmol/L,the difference was statistically significant compared with the control group(P<0.05).2.LFLIU inhibited C6 and U87 cell growth in an intensity-dependent manner.Compared with the control group,for C6 cells,when the intensity of LFLIU is more than142m W/cm~2,the difference was statistically significant(P<0.05).For U87 cells,when the intensity of LFLIU is more than 83.4m W/cm~2,the difference was statistically significant(P<0.05).3.The inhibition rate of C6 and U87 cells decreased after treatment of the combination of LFLIU and curcumin compared with that of curcumin or LFLIU alone respectively(P<0.05).4.LFLIU and curcumin can promote glioma cell morphological changes,showing typical characteristics of apoptosis.5.LFLIU and curcumin can reduce the expression of Survivin in protein level.And synergistic effects were observed significantly in the combination of LFLIU and curcumin.6.VEGF and MRP1 expressed highly in glioma cells.LFLIU and curcumin could decreased the expression of VEGF and MRP1.Furthermore,the combination of LFLIU and curcumin could down-regulate the expression of VEGF and MRP1 significantly compared with those of curcumin or LFLIU alone respectively(P<0.05).7.LY294002 could down-regulate MRP1 expression,however,VEGF blocked this effect.Conclusions:LFLIU and curcumin alone or in combination can inhibit the growth of glioma cells.They can also down-regulate the expression of VEGF and MRP1 in m RNA and protein levels.The down-regulating of MRP1 may be related with VEGF/PI3K/Akt in glioma.