Promoter characterization of Semaphorin SEMA3F, a tumor suppressor gene.
The tumor suppressor gene, Semaphorin SEMA3F, is frequently downregulated in lung cancer. Understanding the specific mechanism of SEMA3F suppression should be informative in terms of epithelial carcinogenesis and potential therapeutic interventions. Although a CpG-island is located 5083-3927 nt upstream of the translation start site, there have been no previous reports dealing with SEMA3F promoter regulation. We have now mapped the transcriptional initiation sites within the CpG-island and defined the region necessary for transcriptional activation. We then looked for evidence of SEMA3F promoter methylation since SEMA3F mutations are rare. By Southern blot and methylation-specific PCR assays, we identified a region in cell lines (i.e., area d at position minus 3850-3644 nt) for which methylation was significantly (P<0.0001) correlated with loss of expression. However, histone deacetylase inhibition with Trichostatin A was much more effective than 5-aza-2'-deoxycytidine in stimulating SEMA3F. Our results suggest that while SEMA3F promoter methylation correlates with repression, chromatin remodeling through histone deacetylase inhibition is sufficient to activate SEMA3F expression.
Kusy
Sophie
S
CNRS UMR 6187, IPBC, Faculté des Sciences de Poitiers, 40 Av du Recteur Pineau, 86022 Poitiers Cédex, France.
Potiron
Vincent
V
Zeng
Chan
C
Franklin
Wilbur
W
Brambilla
Elisabeth
E
Minna
John
J
Drabkin
Harry A
HA
Roche
Joëlle
J
D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D001483:Base Sequence; D015139:Blotting, Southern; D045744:Cell Line, Tumor; D019295:Computational Biology; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation; D017931:DNA Primers; D000077209:Decitabine; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000235:genetics*; D016147:Genes, Tumor Suppressor; D056572:Histone Deacetylase Inhibitors; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D008156:Luciferases; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012313:RNA / Q000378:metabolism*
D017931:DNA Primers; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C491230:SEMA3F protein, human; C012589:trichostatin A; D012313:RNA; D000077209:Decitabine; D008156:Luciferases; D001374:Azacitidine