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 mu M 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.