Selenium inhibits apoptosis and GSH extrusion induced by DHA in human Paca-44 cell line

Aim of the Study. Considering that the possible interactions between selenium (Se) and docosahexaenoic acid (DHA) in regulating various physiopathological responses in cancer cell lines have not been elucidated and defined yet, the aim of this work was to investigate the effects of the co-treatment of DHA with Se on cellular redox state, apoptosis induction and glutathione content in human pancreatic PaCa-44 cancer cells line. Methods. The human PaCa-44 pancreatic adenocarcinoma cell line was treated with docosahexaenoic acid or arachidonic acid (ARA), alone or in co-cultures with sodium selenite (Na2SeO3). After treatments cell viability was analyzed by Trypan blue dye exclusion assay and apoptosis was evaluated by Annexin V/FITC kit. Moreover cellular oxidative status was assessed measuring the levels of ROS by cell-permeable 2’,7’-dichlorofluorescein diacetate (DCFH-DA), the glutathione peroxidase (GSHPx) activity by spectrophotometric analysis and lipid peroxidation by TBA-method. The intracellular glutathione level was determined by HPLC. Results. The results herein reported show that sodium selenite inhibits both the pro-oxidant and the pro-apoptotic effects induced by DHA. Conclusion. This study suggests that sodium selenite, is able to inhibit the GSH reduction and this gives an important indication for the study of a new functional property of Se. Moreover our experimental results indicated that sodium selenite interferes with the pro-oxidant and pro-apoptotic actions of DHA, which is considered as a potential adjuvant in the treatment of cancer.