Selenium effectively inhibits 1,2-dihydroxynaphthalene-induced apoptosis in human lens epithelial cells through activation of PI3-K/Akt pathway

PURPOSE: To investigate whether activation of the phosphatidylinositol 3-kinase (PI3-K)/protein kinase B (Akt) pathway was necessary for selenium in protecting human lens epithelial cells (hLECs) from 1,2-dihydroxynaphthalene (1,2-DHN)-induced apoptosis. In addition, we studied the link between heat shock protein 70 (HSP70) expression and Akt phosphorylation in selenium-induced cell protection. METHODS: Cell viabilities were assessed by Cell Counting Kit-8 (CCK-8) kit and trypan blue exclusion. The effect of sodium selenite on Akt phosphorylation was studied. After the pretreatment with 30 μM of LY294002, a PI3-K/Akt pathway inhibitor, apoptosis was assessed by flow cytometry, protein levels of phospho-Akt and Akt were quantified by western blot, and cell localization of phospho-Akt was determined by immunofluorescence staining. Time-course effect of sodium selenite on HSP70 expression was studied by reverse transcription polymerase chain reaction (RT–PCR) and western blot. Moreover, effect of LY294002 on HSP70 expression was also examined. RESULTS: Our data showed that sodium selenite increased cell viabilities and prevented 1,2-DHN-induced apoptosis through phosphorylation and nuclear translocation of Akt. Furthermore, pretreatment of LY294002 inhibited the phosphorylation of Akt. However, it failed to block the selenium-induced upregulation of HSP70. CONCLUSIONS: The activation of PI3-K/Akt pathway was necessary for selenium in protecting hLECs from 1,2-DHN-induced apoptosis. However, this pathway was not involved in the selenium-induced upregulation of HSP70.