Experimental Study Of MDR-reversing Effect Of Arsenic Trioxide On Human Hepatocellular Carcinoma HepG2/ADM

Objective To study the MDR-reversing effect of arsenic trioxide on human hepatocellular carcinoma HepG2/ADM in vitro and its potential mechanism.Methods MTT assay was used to test the toxicity of the arsenic trioxide and the chemosensitivity to chemotherapeutics in arsenic trioxide–treated HepG2 and HepG2/ADM cell lines. Flow cytometry was used to determine intracellular ADM (Adriamycin) concentration. The expression of mdr1 was measured by RT-PCR.Results1.Study of cytotoxicity of As2O3 on HepG2 and HepG2/ADM cells.At 0.25 mg/L no significant toxicity of As2O3 on HepG2 and HepG2/ADM cells were observed ,but it increased in a dose dependent manner with a concentration higher than 0.25 mg/L, IC50 was 1.02mg/L,1.34mg/L respectively.2. As2O3 can improve cell sensivity to anticancer drugs. With a concentration of 0.2 mg/L, IC50 of ADM,CDDP,MMC, 5-FU to HepG2,HepG2/ADM were significantly decreased. As2O3 can reversed HepG2/ADM cells resistance to chemotherapeutics by 2.92,3.09,2.13,2.60 times(ADM, CDDP, MMC, 5-FU, respectively).3. As2O3 can increased drug concentration in HepG2 and HepG2/ADM cells.When used in combination with As2O3, intra-cellular cumulant of ADM were significantly increased compared with the control group.4. As2O3 can decreased the expression of Pgp in HepG2/ADM cells.After As2O3 treatment,the expression of Pgp as showed by mean intra-cellular fluorescence intensity were decreased compared with the control group(5.65±0.03 vs 7.22±0.23).5. As2O3 can down-regulatethe expression of mdr1 in HepG2/ADM cells. RT-PCR results showed: the expression of mdr1 in HepG2 cells were weaker than in HepG2/ADM cells, which changed little after As2O3 treatment.But in HepG2/ADM cells, the expression decreases significantly after treatment with 0.2 mg/L As2O3 for 48 hours, which were still higher than in HepG2 cells.Conclusions1. As2O3 can reverse multidrug resistance of human hepatoma carcinoma cells, with is associated with decreasing the expression of mdr1 and increasing intra-cellular drug cumulant.2. As2O3 could significantly reversed multidrug resistance of hepatoma, which provide a new strategy for hepatoma chemotherapy.