Effect Of EGCG On Expression Of RECK And Its Modulating Mechanism In Gastric Cancer Cell Line MGC803

Objective: This study was designated to investigate the effect of epigallocatechin-3-gallate (EGCG) on the methylation of RECK and its mRNA expression level in a cell line of MGC803, and elucidate the role of NF-κB on the effect caused by EGCG, thus provide theoretical basis for oncotherapy.Methods: The cultured MGC803 cells were incubate with EGCG for appropriate times. After that, DNA was extracted, and the methylation in RECK promoter region was determined by methylation-specific PCR (MSP). The mRNA level of RECK was detected by RT-PCR. Total protein and nucleoprotein were extracted, and the nuclear translocation of p65 was detected by Western blot for study activation of NF-κB. Pyrrolidine dithiocarbamate(PDTC), a specific inhibitor, was used to elucidate the effect of NF-κB caused by EGCG,.Result1. MSP results showed non-methylation band and methylation band was detected when MGC803 cells was under quiescent condition. When the cells was incubated with 50μM EGCG, the methylation band level was decreased, and the non-methylation was DNA increased.2. RT-PCR showed the mRNA level of RECK increased in dose and time-dependent manner after MGC803 cells was treated with EGCG.3. The p65 translocated to the nucleus when MGC803 cells were under quiescent condition, and the level decreased after incubated with EGCG.4. PDTC could inhibit p65 translocation, and increase the mRNA level of RECK in MGC803 cells.Conclusion1. EGCG could decrease the methylation level in the RECK promoter region in MGC803 cells.2. EGCG could increase the MGC803 cells'RECK mRNA level in dose and time-dependent manner.3. EGCG could inhibit NF-κB activation, and thus induced the expression of RECK.