Abstract: Abstract Objective: To investigate the mechanism of reversing effect of Quercetin on MDR of human hepatocellular carcinoma ( HCC) in the course of genetic transcription by q-PCR microarray.Methods: Human hepatocellular carcinoma cell line Bel-7402 and 5-FU resistant cell line Bel-FU were cultured in vitro. The cytotoxicity and dose-dependen reverse effect of Quercetin were detected by MTT assay. The different gene expression profiles between Bel-7402 and Bel-FU cells ,and those between Bel-FU and Bel-FU cells treated with Quercetin were detected by q-PCR microarray . Then the gene expression of H-ras，MDR1 were detected by real-time quantitative PCR and the expression of P-gp were detected by western-blot to confirm the results of q-PCR microarray .Results: The 10% inhibitory concentration(IC10) as to Bel-7402 and Bel-FU cells were 59.2、58.2μM ，and IC50 were226.7、193.9μM respectively。16.5、33.0、49.5 μM Quercetin reversed the MDR by1.14、1.68、2.38 folds respectively . Compared with those in Bel-7402, and the gene expression of H-ras，Bcl-2，PDGFA，MDR1，BCRP were up-regulated （P＜0.05），The gene expression of H-ras、EGFR、FGF、VEGFA、PDGFA、MDR1、Erk1 were down-regulated in Bel-FU treated with Quercetin（P＜0.05），the real-time quantitative PCR and western-blot comfirmed that gene H-ras，mdr1 and P-gp expression were were down-regulated by Quercetin，they were in accordanc with the result of q-PCR microarray . Conclusion: Quercetin can reverse the up-regulated expression of difference gene in resistant cell line so as to reverse the MDR of human HCC cells.

Key words: Quercetin, q-PCR microarray, hepatocellular carcinoma, multidrug resistance