[Effect of realgar on induction of apoptosis in DLBCL cell line SU-DHL-4 and its possible mechanisms].

ABSTRACT

This study was aimed to explore the effect of realgar (As4S4) on growth inhibition and apoptosis induction of DLBCL cell line SU-DHL-4 and its mechanisms. The inhibitory effect of realgar on the cell growth were detected by MTT method. The morphological changes of SU-DHL-4 were observed by transmission electron microscopy (TEM). The apoptosis of SU-DHL-4 cells treated with realgar were detected by flow cytometry with Annexin V-FITC/PI double staining and DNA agarose gel electrophoresis. The cell cycle was examined by flow cytometry with PI staining. The expressions of apoptosis-related proteins (BCL-2 , Caspase-3,BAX) were detected by Western blot. The results showed that the realgar at the concentration of 20, 40, 80 µmol/L all could inhibit the proliferation of SU-DHL-4 (P < 0.05), and in a certain time and concentration range, the inhibition rate was enhanced in a time and dose dependent manner(r = 0.982). Flow cytometric test results showed that realgar could induce SU-DHL-4 cell apoptosis after treating for 48 hours, and the apoptosis rate increased with the increasing of drug concentration (P < 0.05). After treating SU-DHL-4 cells with Realgar for 48 h, the cell cycle was blocked in the S phase (P < 0.05). TEM results revealed that when treated with realgar for 48 h, the typically apoptosis morphology-apoptotic bodies were observed in all drug-treated group, furthermore, some necrotic cells in the 80 µmol/L group were observed. After intervened by realgar for 48 h, the DNA Ladder pattern was seen according to agarose gel electrophoresis. Western blot showed that the expression of Bcl-2 protein was down-regulated while the expressions of BAX and Caspase-3 protein were up-regulated when treating SU-DHL-4 cells with realgar for 48 h. It is concluded that realgar can inhibit cell growth and induce cell apoptosis, which may be related with up-regulation of Caspase-3 and BAX expression and down-regulation the of BCL-2 expression.