SLC5A8, a sodium transporter, is a tumor suppressor gene silenced by methylation in human colon aberrant crypt foci and cancers.
نویسندگان
چکیده
We identify a gene, SLC5A8, and show it is a candidate tumor suppressor gene whose silencing by aberrant methylation is a common and early event in human colon neoplasia. Aberrant DNA methylation has been implicated as a component of an epigenetic mechanism that silences genes in human cancers. Using restriction landmark genome scanning, we performed a global search to identify genes that would be aberrantly methylated at high frequency in human colon cancer. From among 1,231 genomic NotI sites assayed, site 3D41 was identified as methylated in 11 of 12 colon cancers profiled. Site 3D41 mapped to exon 1 of SLC5A8, a transcript that we assembled. In normal colon mucosa we found that SLC5A8 exon 1 is unmethylated and SLC5A8 transcript is expressed. In contrast, SLC5A8 exon 1 proved to be aberrantly methylated in 59% of primary colon cancers and 52% of colon cancer cell lines. SLC5A8 exon 1 methylated cells were uniformly silenced for SLC5A8 expression, but reactivated expression on treatment with a demethylating drug, 5-azacytidine. Transfection of SLC5A8 suppressed colony growth in each of three SLC5A8-deficient cell lines, but showed no suppressive effect in any of three SLC5A8-proficient cell lines. SLC5A8 exon 1 methylation is an early event, detectable in colon adenomas, and in even earlier microscopic colonic aberrant crypt foci. Structural homology and functional testing demonstrated that SLC5A8 is a member of the family of sodium solute symporters, which are now added as a class of candidate colon cancer suppressor genes.
منابع مشابه
Biological functions of SLC5A8, a candidate tumour suppressor.
SLC5A8 is a candidate tumour suppressor gene that is silenced in colon cancer, gastric cancer and possibly other cancers in humans. This gene codes for a transporter belonging to the Na(+)/glucose co-transporter gene family (SLC5). The cancer-associated silencing of the gene involves hypermethylation of CpG islands present in exon 1 of the gene. SLC5A8 is expressed in colon, ileum, kidney and t...
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ورودعنوان ژورنال:
- Proceedings of the National Academy of Sciences of the United States of America
دوره 100 14 شماره
صفحات -
تاریخ انتشار 2003