Fig. 2.
SLC5A8 expression. (A) RT-PCR analysis demonstrating SLC5A8 transcript expression in three normal colon mucosa samples (N1, N2, and N3) but the absence of SLC5A8 transcript in most colon cancer cell lines (remaining samples). (B) RT-PCR analysis demonstrating reactivation of SLC5A8 expression in cell lines treated with 5-azacytidine (+) compared with untreated controls (-). (C) MS-PCR assay for methylated (M) or unmethylated (U) SLC5A8 exon 1 sequences detects exclusively methylated templates in SLC5A8-silenced cell lines. (D) MS-PCR detects only unmethylated SLC5A8 templates in SLC5A8-expressing cell lines. (E) MS-PCR detection of methylated SLC5A8 templates in colon cancer tumors (T) antecedent to SLC5A8-methylated cell lines (V425 and V670). Matched normal colon tissue (N) shows only unmethylated templates. Unmethylated templates in tumor tissue presumptively arise from contaminating nonmalignant cells. (F) MS-PCR analysis of colon cancer tumors (T) and matched normal colon tissues (N). Methyl-specific bands are seen in each of the tumor samples but none of the normal controls.