Achiwa Yumiko, Hasegawa Kiyoshi, Udagawa Yasuhiro
Faculty of Obstetrics and Gynecology, School of Medicine, Fujita Health University, 1-98 Dengaku gakubo kutukake-cho, Toyoake-shi, Aichi 470-1192, Japan.
Oncol Rep. 2005 Aug;14(2):507-12.
We studied the effect of ursolic acid, a pentacyclic triterpene acid, on the growth of poorly differentiated type endometrial cancer HEC108 cells in vitro. Ursolic acid strongly inhibited the growth of HEC108 cells in a dose- and time-dependent manner. Morphological changes characteristic of apoptosis were observed in ursolic acid-treated cells, such as the presence of apoptotic bodies and fragmentation of DNA to oligonucleosomal-sized fragments. Investigation of caspase activity in ursolic acid-treated HEC108 cells showed that exposure at 50, 75 or 100 microM induced marked increases in caspase-3 activity (after 24 h) to 5.00, 11.76 or 12.75 times that of control levels, while cleaved caspase-3 levels increased in dose-dependent manner after 24 h. Activation of caspase was shown to lead to the cleavage of target proteins such as PARP. Ursolic acid treatment also resulted in a cleavage of poly(ADP-ribose) polymerase in a dose-dependent manner. Testing whether caspase-3 activation and DNA polymerase activity were inhibited by the addition of Ac-DEDV-HOC during ursolic acid treatment showed that 50 microM Ac-DEDV-HOC inhibited caspase-3 activity in treated cells. A mitochondrial pathway has been suggested to be involved in ursolic acid-induced apoptosis because the treatment induces mitochondria cytochrome c release. Experimentally, we found that anti-apoptotic Bcl-2 protein levels decreased after ursolic acid treatment, while Bax expression increased. Our results indicated that ursolic acid induced apoptotic processes in these poorly differentiated endometrial cancer cells occurs through mechanisms involving mitochondrial pathways and Bcl-2 family proteins.
我们研究了五环三萜酸熊果酸对低分化型子宫内膜癌HEC108细胞体外生长的影响。熊果酸以剂量和时间依赖性方式强烈抑制HEC108细胞的生长。在经熊果酸处理的细胞中观察到凋亡特有的形态学变化，如凋亡小体的存在以及DNA断裂成寡核小体大小的片段。对经熊果酸处理的HEC108细胞中半胱天冬酶活性的研究表明，在50、75或100微摩尔浓度下处理24小时后，半胱天冬酶-3活性显著增加，分别是对照水平的5.00、11.76或12.75倍，而裂解的半胱天冬酶-3水平在24小时后呈剂量依赖性增加。已证明半胱天冬酶的激活会导致靶蛋白如PARP的裂解。熊果酸处理还导致聚（ADP - 核糖）聚合酶以剂量依赖性方式裂解。在熊果酸处理期间添加Ac - DEDV - HOC测试半胱天冬酶-3激活和DNA聚合酶活性是否受到抑制，结果表明50微摩尔的Ac - DEDV - HOC抑制了处理细胞中的半胱天冬酶-3活性。由于该处理诱导线粒体细胞色素c释放，提示线粒体途径参与了熊果酸诱导的凋亡。实验中，我们发现熊果酸处理后半凋亡蛋白Bcl - 2水平降低，而Bax表达增加。我们的结果表明，熊果酸诱导这些低分化子宫内膜癌细胞凋亡的过程是通过涉及线粒体途径和Bcl - 2家族蛋白的机制发生的。
