Inhibitory effect of lignans from Ailanthus altissima on proliferation of human lung cancer cells and its mechanism.

Abstract

e15059 Background: Plants are thought to contain compounds that inhibit the proliferation of cancer cells in vitro, and many attempts have been made to isolate anti-cancer drugs from plants. Ailanthus altissima is a family of Simaroubaceae, the bark is gray to grayish-black, because of the smell of the gland patches at the base of the leaves. 3,5,3-trimethoxy-8,1-neoligna-4,2,7,9,9-pentol (TNP) isolated from Ailanthus altissima. Methods: (1) Apoptosis was detected by flow cytometry: the cells were incubated with 10 mmol/L TNP for 24 h, and the cells were collected. The cell concentration was adjusted to 5×105 ̃ 5×106/ L. While propionate iodide was added for DNA fluorescence staining (Propidium Iodide, PI: 50 mg/L，triton-x100 1.0%). (2) The changes of p53, Bax and caspase-3 were detected by Western blot. The cells were cultured in 10 μmol/L cisplatin and TNP medium for 24 hours. Image J image analysis software is used for semi quantitative analysis. The data were expressed by mean standard deviation, and the mean values of each group were compared by analysis of variance and the least significant difference. There was a significant difference in P< 0.05. (3) A549 cells were treated with 10 μmol/L cisplatin and TNP. A549 cells were incubated with cisplatin and TNP, and then treated with solvent control (final concentration 0.1% dimethyl sulfoxide) with or without caspase inhibitor for 48 hours The OD value was determined by MTT method. Cell survival rate (%) = (OD value of control group /OD value of control group) 100%. Results: (1) The reverse effect of caspase inhibitor on the proliferation of A549 cells: the cell survival rates of A549 cells treated with 0.1, 1 and 10 μmol/L cisplatin and TNP were 96.11%, 72.36%, 27.57% and 71.42%, 28.97% and 4.34% respectively. The survival rate of A549 cells incubated with cisplatin and TNP 20 μmol/L increased to 100.00%, 81.92%, 57.54% and 85.69%, 48.57% and 16.95% respectively. Caspase inhibitor reversed the inhibitory effect of TNP on A549 cells. (2) The effect of TNP on apoptosis of A549 cells: after treatment with 10 μmol/L TNP for 24 h, the apoptosis rate of A549 cells was (24.01)%, which was significantly higher than that of the blank control group (6.79)% ( P< 0.05). (3) The results showed that the up regulation of p53, Bax and caspase-3 protein by TNP was 10 μmol/L. Conclusions: TNP can induce apoptosis of human lung cancer cell line A549, and it can up regulate the expression of p53, Bax and Caspase-3, which may be one of the mechanisms of TNP inducing apoptosis of A549 cells. The experiment also proves that caspase inhibitor can reverse the effect of TNP. TNP inhibits the proliferation of A549 cells.