[Expression of MAGE-A1 in human hepatoma cell lines associated with genic hypomethylation]

To investigate the correlation between MAGE-A1 mRNA expression and genic demethylation in hepatoma cell lines.

Total RNA and genomic DNA were prepared from 10 human hepatoma cell lines. MAGE-1 mRNA expression was determined with RT-PCR and the level of genome-wide demethylation was evaluated by enzyme digestion and Southern blot assay. The genomic DNA was digested by HpaII, then the promoter of MAGE-A1 gene was amplified with primers CDS21, EDP4 and CDS20. EDP4 and the PCR products were further hybridized with a probe to detect the methylation in the promoter of the MAGE-A1 gene. HLA-A locus was typed using SSP kit.

In cell lines QGY-7703, SMMC-7721, HLE, BEL-7402, BEL-7404 and BEL-7405, MAGE-A1 mRNA expression was positive and cell differentiation was moderate or low. In cell lines of HepG2 2.2.15, HepG2, QGY-7701 and Huh7, MAGE-A1 mRNA expression was negative and cell differentiation was well or moderate. The level of genomic demethylation in MAGE-A1 mRNA positive cell lines was much higher than that in MAGE-A1 mRNA negative cell lines (t = 2.896, P = 0.02). The methylation analysis showed that methylation in the promoters of MAGE-A1 gene of HepG2 2.2.15, HepG2, QGY-7701 and Huh7 was high, and that methylation in those of SMMC-7721, HLE, BEL-7402, BEL-7404, and BEL-7405 was low.

The results suggest that MAGE-A1 mRNA expression in the human hepatoma cell lines is associated with genic hypomethylation.