Withaferin A causes FOXO3a- and Bim-dependent apoptosis and inhibits growth of human breast cancer cells in vivo.
Withaferin A causes FOXO3a- and Bim-dependent apoptosis and inhibits growth of human breast cancer cells in vivo.
复制标题
DOI：
10.1158/0008-5472.can-08-1510
复制
发表时间：
2008-09-15
期刊：
影响因子：
11.2
通讯作者：
Singh, Shivendra V.
中科院分区：
文献类型：
--
作者：
Stan, Silvia D.;Hahm, Eun-Ryeong;Warin, Renaud;Singh, Shivendra V.
Withaferin A （WA）是从药用植物Withania somnifera中提取的，在印度阿育吠陀医学中被安全使用了几个世纪，用于治疗不同的疾病。我们现在首次证明，WA在培养和体内对人类乳腺癌细胞表现出显著的活性。WA治疗降低MCF-7（雌激素应答）和MDA-MB-231（雌激素非依赖型）人乳腺癌细胞的活力呈浓度依赖性。wa介导的乳腺癌细胞活力的抑制与细胞凋亡诱导相关，其特征是DNA浓缩、细胞质组蛋白相关的DNA片段化和聚（adp核糖）聚合酶的裂解。另一方面，与乳腺癌细胞相比，自发永活的正常乳腺上皮细胞系（MCF-10A）对wa诱导的凋亡具有相对更强的抵抗力。wa介导的凋亡伴随着MCF-7细胞中Bim-s和Bim-L的诱导，以及MDA-MB-231细胞中Bim-s和Bim-EL亚型的诱导。在两种细胞系中，通过敲低Bim及其转录调节因子FOXO3a的蛋白水平，WA暴露导致的细胞质组蛋白相关DNA片段明显减弱。此外，FOXO3a敲除对wa介导的诱导Bim-s表达具有显著的保护作用。每周5次腹腔注射4 mg WA/kg体重可显著延缓雌性裸鼠MDA-MB-231细胞的生长。与对照组小鼠相比，wa处理小鼠的肿瘤表现出细胞增殖减少和细胞凋亡增加。这些结果表明FOXO3a和Bim在调节wa介导的人乳腺癌细胞凋亡中起重要作用。
Withaferin A (WA) is derived from the medicinal plant Withania somnifera which has been safely used for centuries in Indian Ayurvedic medicine for treatment of different ailments. We now demonstrate, for the first time, that WA exhibits significant activity against human breast cancer cells in culture and in vivo. The WA treatment decreased viability of MCF-7 (estrogen-responsive) and MDA-MB-231 (estrogen-independent) human breast cancer cells in a concentration-dependent manner. The WA-mediated suppression of breast cancer cell viability correlated with apoptosis induction characterized by DNA condensation, cytoplasmic histone-associated DNA fragmentation, and cleavage of poly-(ADP-ribose)-polymerase. On the other hand, a spontaneously immortalized normal mammary epithelial cell line (MCF-10A) was relatively more resistant to WA-induced apoptosis compared with breast cancer cells. The WA-mediated apoptosis was accompanied by induction of Bim-s and Bim-L in MCF-7 cells and induction of Bim-s and Bim-EL isoforms in MDA-MB-231 cells. The cytoplasmic histone-associated DNA fragmentation resulting from WA exposure was significantly attenuated by knockdown of protein levels of Bim and its transcriptional regulator FOXO3a in both cell lines. Moreover, FOXO3a knockdown conferred marked protection against WA-mediated induction of Bim-s expression. The growth of MDA-MB-231 cells implanted in female nude mice was significantly retarded by five weekly i.p. injections of 4 mg WA/kg body weight. The tumors from WA-treated mice exhibited reduced cell proliferation and increased apoptosis compared with tumors from control mice. These results point towards an important role of FOXO3a and Bim in regulation of WA-mediated apoptosis in human breast cancer cells.