Background & objective: Catechin is composed of a variety of components,some of which have anti-cancer activity. There was no report on effect of catechin on the multidrug resistance of hepatocellular carcinoma so far. The aim of this study was to investigate the MDR-reversing effect of two components of catechin on human hepatocellular carcinoma BEL-7404/Adr in vitro and its potential mechanism.
Methods: MTT was used to test the toxicity of the two components of catechin. The concentration of the drugs inside the cells was determined by fluorospectro-photometry and the expression of MDR1 was measured by RT-PCR.
Results: The inhibition rates of BEL-7404/Adr caused by two components of catechin were less than 10% under the dose of 100 mg/L. Epicatechin gallate (ECG) in 60 mg/L or epigallocatechin gallate (EGCG) in 14 mg/L has slight cytotoxicity, but they could decrease the IC(50) of adriamycin (ADM) for BEL-7404/Adr from 36 mg/L to 2.3 mg/L or 1.9 mg/L, respectively, and the reversing folds were 15.8 and 19.2, respectively. The combined administration could increase the concentration of ADM in BEL-7404/Adr cells from 0.76 microg/10(8) cells-2.55 microg/10(8) cells to 2.04 microg/10(8) cells -9.28 microg/10(8) cells (P< 0.01). The expression of MDR1 was down-regulated by 27.6% and 41.3%, respectively. Furthermore, EGCG is the stronger one.
Conclusion: ECG and EGCG can reverse the multi-drug resistance of human hepatocellular carcinoma in vitro. The possible mechanism is related to down-regulating the expression of MDR1 and raising the concentration of drugs inside the cells.