Li Yue, Wang Ying, Wang Suihai, Gao Yanjun, Zhang Xuefeng, Lu Chunhua
State Key Laboratory of Oncology in Southern China, Sun Yat-Sen University Cancer Center, Guangzhou, China.
Med Oncol. 2015 Jan;32(1):365. doi: 10.1007/s12032-014-0365-1. Epub 2014 Dec 10.
Oridonin is an active diterpenoid, which was extracted from traditional Chinese herbs and had been widely used in clinical treatment nowadays. Oridonin phosphate is one of the derivatives of oridonin. In the present study, we explored its anti-tumor effect and investigated the molecular mechanism of oridonin phosphate in breast cancer cell lines. Firstly, cell viability was analyzed by MTT assay. The breast cancer cells were treated with increasing concentrations of oridonin phosphate for 24, 48 and 72 h, respectively. The results demonstrated that oridonin phosphate inhibited the proliferation of MDA-MB-436 and MDA-MB-231 cells in a dose- and time-dependent manner. Next, cell apoptosis rate was detected in oridonin phosphate-treated breast cancer cells by Annexin V-FITC/PI dual staining analysis and the data demonstrated that oridonin phosphate induced cell apoptosis of breast cancer cells in time- and dose-dependent manner. Moreover, apoptosis-related proteins were detected by Western blotting analysis. The results showed that the expression level of Bax was up-regulated and the expression level of Bcl-2 was down-regulated. Meanwhile, the level of cleaved caspase-9 was significantly increased when the cells were treated with 40 μM of oridonin phosphate for 48 h, although the expression level of pro-caspase-9 was not obviously changed. All of the data revealed that mitochondrial apoptosis pathway may be involved in the cell apoptosis induced by oridonin phosphate in breast cancer cells. Importantly, the expression levels of autophagy-related protein beclin-1 and LC3-II were significantly higher in oridonin phosphate-treated breast cancer cell lines MDA-MB-436 and MDA-MB-231 for 48 h. Additionally, we further explored the relationship between apoptosis and autophagy specifically induced by oridonin phosphate in breast cancer cells. The result showed that inhibition of autophagy suppressed the cell apoptosis in oridonin phosphate-treated MDA-MB-436 cells. Taken together, the compound of oridonin phosphate simultaneously induced cell apoptosis and autophagy in breast cancer cells. Inhibition oridonin phosphate-induced cell autophagy suppressed the progression of cell apoptosis, which revealed that oridonin phosphate-induced autophagy participated in up-regulation of apoptosis in human breast cancer cells. It would provide some new clues for the therapy of breast cancer.
冬凌草甲素是一种活性二萜类化合物,它从传统中草药中提取而来,如今已广泛应用于临床治疗。磷酸冬凌草甲素是冬凌草甲素的衍生物之一。在本研究中,我们探究了其抗肿瘤作用,并研究了磷酸冬凌草甲素在乳腺癌细胞系中的分子机制。首先,通过MTT法分析细胞活力。分别用不同浓度的磷酸冬凌草甲素处理乳腺癌细胞24、48和72小时。结果表明,磷酸冬凌草甲素以剂量和时间依赖性方式抑制MDA-MB-436和MDA-MB-231细胞的增殖。接下来,通过Annexin V-FITC/PI双染分析检测磷酸冬凌草甲素处理的乳腺癌细胞的凋亡率,数据表明磷酸冬凌草甲素以时间和剂量依赖性方式诱导乳腺癌细胞凋亡。此外,通过蛋白质免疫印迹分析检测凋亡相关蛋白。结果显示,Bax的表达水平上调,Bcl-2的表达水平下调。同时,当细胞用40μM磷酸冬凌草甲素处理48小时时,cleaved caspase-9的水平显著增加,尽管pro-caspase-9的表达水平没有明显变化。所有数据表明,线粒体凋亡途径可能参与了磷酸冬凌草甲素诱导的乳腺癌细胞凋亡。重要的是,在磷酸冬凌草甲素处理48小时的乳腺癌细胞系MDA-MB-436和MDA-MB-231中,自噬相关蛋白beclin-1和LC3-II的表达水平显著更高。此外,我们进一步探究了磷酸冬凌草甲素在乳腺癌细胞中特异性诱导的凋亡与自噬之间的关系。结果显示,抑制自噬可抑制磷酸冬凌草甲素处理的MDA-MB-436细胞的凋亡。综上所述,磷酸冬凌草甲素化合物同时诱导乳腺癌细胞凋亡和自噬。抑制磷酸冬凌草甲素诱导的细胞自噬可抑制细胞凋亡的进程,这表明磷酸冬凌草甲素诱导的自噬参与了人乳腺癌细胞凋亡的上调。这将为乳腺癌的治疗提供一些新线索。