一种海洋来源的ETP类化合物HDN-1诱导K562细胞凋亡作用及机制初探

目的 探讨南极土壤来源真菌的次级代谢产物HDN-1对人慢性粒细胞白血病K562细胞的增殖抑制,诱导凋亡作用及其机制。方法 采用MTT法检测HDN-1对K562细胞的增殖抑制作用；DNA结合染料Hoechst 33342染色,Western Blotting以及DNA琼脂糖凝胶电泳检测细胞凋亡以及凋亡相关蛋白的变化。结果 HDN-1能显著抑制K562细胞的增殖,并呈剂量-时间依赖性；HDN-1作用后,细胞核形态发生明显变化并且出现了基因组DNA的梯状剪切条带；Caspase-9、8、3逐渐被激活,Caspase3的作用底物PARP被活化裂解出现89KD的剪切条带,并且Caspase蛋白的激活可被特异性抑制剂所阻断；抑凋亡蛋白Bcl-2,Mcl-1的表达降低,促凋亡蛋白Bax的表达量增高。另外,融合蛋白Bcr-Abl的表达被HDN-1抑制并呈剂量依赖性。结论 来源于南极土壤来源真菌的次级代谢产物HDN-1可能是通过抑制Bcr-Abl融合蛋白的表达进而诱导K562细胞凋亡,并且凋亡是通过Caspase依赖的线粒体途径和死亡受体途径共同介导发生的。

Apoptosis-inducing effects of a marine source ETP compound HDN-1 and its preliminary mechanism exploration

Objective To investigate the mechanisms of human erythro-leukemia K562 cells proliferation and apoptosis induced by HDN-1 which was the secondary metabolites of antarctic soil fungi Oidiodendron truncatum GW3-13. Methods MTT assay was applied to examine the effect of HDN-1 on the proliferation inhibition of K562 cells. Hoechst 33342 staining, DNA agarose gel electrophoresis and Western Blotting were used to detect the apoptosis of K562 cells. Results HDN-1 could inhibit the proliferation and induce apoptosis in K562 cells in both time- and dose-dependent manners. Typical morphological changes and DNA fragmentation were observed under the treatment of HDN-1. Western Blotting showed cleavage of the caspase-9, 8, 3 zymogen protein and a 89KD subunit cleavage product of ADP-ribose PARP after the treatment of HDN-1 . Moreover, activation of caspase was dramatically inhibited by caspase specific inhibitor. Western Blotting also revealed that the expression of pro-apoptotic protein Bax was up-regulated significantly accompanied by the decrease of anti-apoptotic protein Bcl-2 and Mcl-1. In addition, the Bcr-Abl protein was decreased by HDN-1 in dose-dependent manners. Conclusion All these results suggest that HDN-1 induces apoptosis of K562 leukemia cells by impeding the expression of Bcr-Abl protein, and the apoptosis of K562 cells depends both on the death receptor pathway and the mitochondrial pathway.