Abstract
Selenium is a chalcogen element that is essential in animals, but is highly toxic when ingested above the nutritional requirement. Selenite is used as a supplement in patients receiving total parenteral nutrition. However, the therapeutic and toxic doses of selenite are separated by a narrow range. This ambivalent character of selenite implies the presence of cellular mechanisms that precisely control selenite homeostasis. Here, we investigated mechanisms that determine cellular susceptibility to selenite exposure. The resistance to selenite exposure was significantly different among cell lines. We determined the expression levels of TPMT (thiopurine S-methyltransferase) and SLC4A1 (solute carrier family 4 member 1), which encode selenium methyltransferase and selenite transporter, respectively. We also examined the effect of inhibition of Band 3 protein activity, which is encoded by SLC4A1, on the cellular sensitivity to selenite. The data suggest that the expression level of SLC4A1 is the determinant of cellular sensitivity to selenite.
Keywords:
Band 3 protein; Chalcogen element; DIDS, 4,4’-diisothiocyanatostilbene-2,2’-disulfonic acid; SLC4A1, solute carrier family 4 member 1; Selenite; Selenium; Solute carrier family 4 member 1; TPMT, thiopurine S-methyltransferase; Thiopurine S-Methyltransferase.