[Impact of epigallocatechin gallate on gene expression profiles of human hepatocellular carcinoma cell lines BEL7404/ADM and BEL7402/5-FU].

BACKGROUND & OBJECTIVE: Epigallocatechin gallate (EGCG) from green tea could reverse multidrug resistance (MDR) in human hepatocellular carcinoma (HCC) in vitro and in vivo. This study was to investigate the mechanism of reversing effect of EGCG on MDR of human hepatocelluar carcinoma cell lines BEL7404/ADM and BEL7402/5-FU.

METHODS: Drug sensitivity of BEL7404/ADM and BEL7402/5-FU cells was tested by MTT assay. The different gene expression profiles of BEL7404/ADM and BEL7402/5-FU cells were detected by cDNA microarray before and after treatment of EGCG. The expression of MDR1 and LRP genes was detemined by reverse transcription-polymerase chain reaction (RT-PCR); the expression of Cyclin G1 protein was detected by Western blot to confirm the results of cDNA microarray.

RESULTS: The 10% inhibitory concentration (IC10) of EGCG was 24.76 mg/L for BEL7404/ADM cells and 20.60 mg/L for BEL7402/5-FU cells. When treated with 0.05 mg/L adriamycin (ADM) and 100 micromol/L 5-fluorouracil (5-FU) in combination, 20 mg/L EGCG reversed the MDR by 9.66 folds in BEL7404/ADM cells and by 2.36 folds in BEL7402/5-FU cells. After treatment of EGCG, 210 differentially expressed genes were identified in BEL7404/ADM cells: 38 were up-regulated and 172 were down-regulated; the potential MDR-related genes included the up-regulated ABCB10 (MDR/TAP), TOP2A, TOP2B, CCNG1, and down-regulated ABCB1, MVP, ARHD, HDAC5, GSS, GSTPI, HSPA1B, HSPB7, CDKN1A, RAB11B, RAB9P40. After treatment of EGCG, 179 differentially expressed genes were identified in BEL7402/5-FU cells: 31 were up-regulated and 148 were down-regulated; the potential MDR-related genes included the up-regulated ABCG (BCRP), CCNG2, GADD34, RB1, RBBP4, and down-regulated DTYMK, GPX1, USP5, BAX, BAK1, HSPA1L. The down-regulation of MDR1 and LRP expression was confirmed by RT-PCR; the up-regulation of Cyclin G1 expression was confirmed by Western blot.

CONCLUSION: EGCG could reverse the MDR of BEL7404/ADM and BEL7402/5-FU cells, but the changes of gene expression profiles of these two HCC cell lines are different.