[Apoptosis-inducing effect of alternol on mouse lymphocyte leukemia cells and its mechanism]

Alternol is purified from fermentation productions of microorganisms named as Alternaria alternata var. monosporus. The research is to investigate the apoptosis-inducing effect of alternol on mouse lymphocyte leukemia (L1210) cells and the possible mechanisms. MTT method was used to evaluate the viability of L1210 cells. Apoptosis of L1210 cells was detected by morphological assessment, DNA electrophoresis assay and flow cytometry. Western blotting analysis was carried out to determine the apoptosis-related proteins. Proliferation inhibition of L1210 cells by alternol was found remarkably in a dose-dependent manner. When treated with alternol, apoptotic morphological features of L1210 cells were observed by fluorescent microscopy (AO/EB) and the apoptosis rate was also elevated in a time-dependent manner. After treatments with various concentrations of alternol for 48 h, DNA laddering appeared. The increase of reactive oxygen species (ROS) production was found after cells were exposed to alternol for 6 h, while the decrease of mitochondrial transmembrane potential (delta psi m) was not found until cells were exposed to alternol for 24 h. Furthermore, the level of Bcel-2 and Bcl-2/Bax was down-regulated, while the level of caspase-3 and caspase-9 but not caspase-8 was up-regulated when alternol was added for 72 h. In summary, the results suggested that alternol could inhibit the proliferation of L1210 cells and induce apoptosis of L1210 cells, which was mediated by mitochondria-dependent pathway.