Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract only
Publication Acceptance Date: 11/10/2006
Publication Date: 4/1/2007
Publication URL: www.fasebj.org
Citation: Uthus, E.O., Begaye, A., Ross, S.A., Zeng, H. 2007. The von Hippel-Lindau (VHL) tumor-suppressor gene is down-regulated in Caco-2 cells incubated in low-selenium (Se) media [abstract]. Journal of Federation of American Societies for Experimental Biology. 21(5):A717. Interpretive Summary:
Technical Abstract: To test the hypothesis that Se affects DNA methylation and hence gene regulation we employed a methylation array (Panomics) in the human colonic epithelial Caco-2 cell model. The array profiles DNA methylation from promoter regions of 82 human genes. After conditioning cells to repeatedly reduced concentrations of fetal bovine serum, a serum-free culture was established. Se-(methyl) selenocysteine (SeMSC) was added at 0 (deficient Se) or 250 (control Se) nM to cells maintained in DMEM. After 7d cells were collected and stored at -80 deg C until analysis; experiments were replicated 3 times. GPx activity was significantly decreased in cells grown in low SeMSC. Cells grown in 250 nM SeMSC had maximal GPx activity. Of the genes profiled, VHL was most different by visual inspection of the arrays suggesting that its promoter was hypermethylated in cells from the low-SeMSC media. To determine whether promoter methylation affected transcription, we isolated RNA from replicate samples and performed real-time RT PCR. VHL was down-regulated (fold change significantly <1) in cells grown in low SeMSC compared to cells grown in 250 nM SeMSC (fold change=1). Treatment GPx, VHL SeMSC mU/Mg protein (+/- SE) fold change (-1 SE, + 1 SE) 0 6.1 +/- 0.45 0.67 (0.62, 0.73) 250 104 +/- 14 1.0 (0.95, 1.05) t-test 0.02 0.007 Our results suggest that low Se status affects DNA methylation and that this can result in down-regulation of the tumor suppressor gene VHL.