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Objective To observe the inhibitory effect of curcumin on the proliferation of multidrug resistance liver cancer line HepG2/ADM cells and to explore its mechanisms.Methods HepG2/ADM cells were prepared and cultured in vitro,and treated by different concentrations (5,10,20,40 μmol/L) of curcumin for 24,48,72 h respectively.The effect of curcumin on proliferation of HepG2/ADM cells was measured by CCK-8 reagent;the concentration of intracellular rhodamine-123 (Rh-123) and adriamycin (ADM) were determined by flow cytometry;the level change of intracellular mdr-1 mRNA in each group was determined by RT-PCR,the P-gp protein level was detected by Western blot.Results Compared with the blank control and DMSO group,curucmin had more obvious inhibitory effect on HepG2/ADM cells proliferation (P＜0.05),and could more remarkably inhibit the intracellular Rh-123 excretion(P＜0.05).The RT-PCR and Western blot results showed that curcumm more significantly decrease the mdr-1 mRNA and P-gp protein levels in dose-time dependent manner (P＜0.05).Conclusion Curcumin could significantly inhibit the proliferation of multidrug-resistant HepG2/ADM cells,and its mechanism may be related with inhibiting mdr-1 gene expression and its encoded P-gp protein level,which are closely related with MDR.
RESUMO
Objective Ginsenoside Rh2 can inhibit the proliferation of a variety of malignant tumor cells.However, little research has been done on the sensitivity of Rh2 in human hepatocellular carcinoma HepG2/ADM cells with multidrug resistance(MDR).This study aimed to explore the reversing effects of ginsenoside Rh2 on the MDR of human hepatocellular carcinoma HepG2/ADM cells and its potential mechanism.Methods MTT assay was applied to detect the effect of Rh2(0-250 μg/mL) on the viability of HepG2/ADM cells and screen out the optimum drug-resistant reversal concentration of Rh2.Cells were divided into 3 groups: HepG2/ADM group (without any medicine treatment), ADM group(ADM treatment for 48 h), ADM+40 μg/mL Rh2 group (pretreatment of 40μg/mL Rh2 for 30 min followed by ADM treatment for 48 h).Flow cytometry was applied to detect the effect of Rh2 on the fluorescence intensity of cellular Rh-123.RT-PCR was used to measure the expression of MDR1 gene.Western blot was used to detect the protein levels of P-gp, Bax, Bcl-2 and cleaved caspase-3.Results 40 μg/mL ginsenoside Rh2 significantly reversed the MDR of HepG2/ADM cells by a 2.55-to-3.70-fold increase in sensitivity.Furthermore, compared with ADM group, the efflux of Rh-123 in HepG2/ADM cells were remarkably inhibited by Rh2 in ADM+40 μg/mL Rh2 group (65.83±1.78 vs 78.21±1.26, P<0.01), along with the down-regulated expressions of MDR1 (0.48±0.02 vs 0.86±0.05, P<0.05), P-gp(0.97±0.04 vs 1.91±0.03,P<0.01), Bcl-2(1.25±0.05 vs 1.86±0.03, P<0.05) and the up-regulated protein level of Bax (1.76±0.04 vs 1.25±0.02,P<0.05) and cleved caspase-3(0.42±0.04 vs 38.26±5.45,P<0.05).Conclusion Ginsenoside Rh2 can effectively reverse the MDR of HepG2/ADM cells, and the potential mechanism is related to the decreased expressions of MDR1 and P-gp, the increasing drug concentration inside the cells and the Bax/Bcl-2 signaling pathway.