Zhao Ying-Yong, Shen Xuefeng, Chao Xu, Ho Charlene C, Cheng Xian-Long, Zhang Yongmin, Lin Rui-Chao, Du Ke-Jun, Luo Wen-Jing, Chen Jing-Yuan, Sun Wen-Ji
Biomedicine Key Laboratory of Shaanxi Province, Northwest University, No.229 Taibai North Road, Xi'an, Shaanxi 710069, China.
Biochim Biophys Acta. 2011 Apr;1810(4):384-90. doi: 10.1016/j.bbagen.2010.12.005. Epub 2011 Jan 15.
Mushrooms have been used in Asia as traditional foods and medicines for a long time. Ergosta-4,6,8(14),22-tetraen-3-one (ergone) is one of the well-known bioactive steroids, which exists widely in various medicinal fungi such as Polyporus umbellatus, Russula cyanoxantha, and Cordyceps sinensis. Ergone has been demonstrated to possess cytotoxic activity. However, the molecular mechanisms by which ergone exerts its cytotoxic activity are currently unknown.
In the present study, ergone possessed a remarkable anti-proliferative activity toward human hepatocellular carcinoma HepG2 cells. We assayed the cell cycle by flow cytometry using PI staining; investigated the exposure of phosphatidylserine at the outer layer of the cytoplasmic membrane by the FITC-annexin V/PI staining; observed the nuclear fragmentation by Hoechst 33258 staining and studied the protein expression of Bax, Bcl-2, p-53, procaspase-3, -8, -9, PARP and cleaved PARP by Western blotting analysis.
Cells treated with ergone showed typical markers of apoptosis: G2/M cell cycle arrest, chromatin condensation, nuclear fragmentation, and phosphatidylserine exposure. Furthermore, PARP-cleavage; activation of caspase-3, -8, -9; up-regulation of Bax and down-regulation of Bcl-2 were observed in HepG2 cells treated with ergone, which show that both the intrinsic and extrinsic apoptotic pathways are involved in ergone-induced apoptosis in HepG2 cells. Ergosta-4,6,8(14),22-tetraen-3-one induces G2/M cell cycle arrest and apoptosis in HepG2 cells in a caspase-dependent manner.
In this study, we reported for the first time that ergone-induced apoptosis through activating the caspase. These results would be useful for the further utilization of many medicinal fungi in cancer treatment.
长期以来，蘑菇在亚洲一直被用作传统食品和药物。麦角甾-4,6,8(14),22-四烯-3-酮（麦角甾酮）是一种著名的生物活性甾体，广泛存在于多种药用真菌中，如猪苓、红菇和冬虫夏草。麦角甾酮已被证明具有细胞毒性活性。然而，目前尚不清楚麦角甾酮发挥其细胞毒性活性的分子机制。
在本研究中，麦角甾酮对人肝癌HepG2细胞具有显著的抗增殖活性。我们使用PI染色通过流式细胞术检测细胞周期；通过FITC-膜联蛋白V/PI染色研究细胞质膜外层磷脂酰丝氨酸的暴露情况；通过Hoechst 33258染色观察核碎裂，并通过蛋白质印迹分析研究Bax、Bcl-2、p-53、procaspase-3、-8、-9、PARP和裂解的PARP的蛋白表达。
用麦角甾酮处理的细胞显示出典型的凋亡标志物：G2/M细胞周期阻滞、染色质浓缩、核碎裂和磷脂酰丝氨酸暴露。此外，在用麦角甾酮处理的HepG2细胞中观察到PARP裂解；caspase-3、-8、-9激活；Bax上调和Bcl-2下调，这表明内源性和外源性凋亡途径均参与了麦角甾酮诱导的HepG2细胞凋亡。麦角甾-4,6,8(14),22-四烯-3-酮以caspase依赖的方式诱导HepG2细胞G2/M细胞周期阻滞和凋亡。
在本研究中，我们首次报道麦角甾酮通过激活caspase诱导凋亡。这些结果将有助于进一步利用多种药用真菌进行癌症治疗。
