Background: Selenium is an essential micronutrient for mammals but toxic in large amounts. Most studies indicate that selenium has inhibitory effect on cancer. The aim of this study is to investigate the effects of selenium and reduced glutathione (GSH) combined application on the proliferation and apoptosis of human lung adenocarcinoma cell line XWLC-05.
Methods: XWLC-05 cells were respectively treated in vitro by four factors (sodium selenite, GSH, sodium selenite+GSH and blank control (RMPI-1640 +10% calf serum) in different concentrations for 24 h. Cell growth inhibition rates were determined by MTT assay, cytomorphology was observed under inverted phase contrast microscope and changes of cell cycle were detected by Flow Cytometry (FCM).
Results: Both selenium and GSH individual on the XWLC-05 cells were found to possess obvious growth inhibition effect on the XWLC-05 cells. Selenium and GSH combined application on the XWLC-05 cells had cooperative inhibition effect (P <0.01). The inhibition rate was increased in a dose-dependent relationship as selenium with concentrations between (0.5-4.0) mug/mL (P <0.01) whether it was selenium single factors or selenium and GSH combined effect. FCM results showed that some XWLC-05 cells were induced apoptosis and G1 phase cells were markedly increased and S, G2/M phase cells decreased in both selenium individual groups and selenium and GSH combined groups.
Conclusions: Selenium and GSH combined application on XWLC-05 cells can enhance directly the cell growth inhibitory effect compared with selenium and GSH individual. The mechanism seems to inhibit the synthesis of RNA and protein and prevent cells from entering S phase.