<i>CLDN11</i> mRNA re-expression in AGS GC cells after 5-aza-2′-deoxycytidine (5-aza-dC) treatment.

<p>AGS is a GC cell line manifesting hypermethylation of the <i>CLDN11</i> promoter in conjunction with absent <i>CLDN11</i> mRNA expression. These cells were treated with 5-aza-dC, a global demethylating agent. Total RNA from AGS cells before and after 5-aza-dC treatment were subjected to quantitative real-time RT-PCR analysis for <i>CLDN11</i> mRNA expression. The <i>Y-axis</i> represents the average fold change in expression levels of <i>CLDN11</i> mRNA after 5-aza-dC treatment at various time points, when compared with the untreated cells. AGS cells, when treated with 5-aza-dC, exhibited a time-dependent increase in <i>CLDN11</i> mRNA expression up to 72 hrs of treatment. This restoration of <i>CLDN11</i> expression after 5-aza-dC treatment supports our hypothesis that claudin-11 is silenced by promoter hypermethylation in GC cells.