Expression of MAGE-A1 mRNA is associated with gene hypomethylation in hepatocarcinoma cell lines

A correlation between melanoma-associated antigen (MAGE) A1 mRNA expression and genome-wide hypomethylation has been observed in some carcinomas, but this relationship is not known in hepatocarcinoma.

Total RNA and genomic DNA were prepared from ten human hepatocarcinoma cell lines in which the genetic characteristics are stable. MAGE-1 mRNA expression was determined by reverse transcription polymerase chain reaction (RT-PCR), and the level of genome-wide demethylation was evaluated by enzyme digestion and Southern-blot assay. The methylation status of the MAGE-A1 gene promoter was measured by enzyme digestion and PCR.

MAGE-A1 mRNA was detected in the hepatocarcinoma cell lines QGY-7703, SMMC-7721, HLE, BEL-7402, BEL-7404, and BEL-7405, which showed moderate to low levels of cell differentiation. In contrast, MAGE-A1 mRNA expression was not detected in the hepatoma cell lines HepG2215, HepG2, QGY-7701, and Huh7, which showed moderate to high levels of differentiation. The level of demethylation in MAGE-A1 mRNA-positive cell lines was much higher than that in MAGE-A1 mRNA-negative cell lines (P=0.02).

The results suggest that MAGE-A1 mRNA expression in human hepatoma cell lines is associated with hypomethylation of the genome and the MAGE-A1 promoter domain. This study will be helpful to reveal the expression mechanisms of MAGE-like tumor antigens in cancer cells.