Chan Chim Kei, Chan Gomathi, Awang Khalijah, Abdul Kadir Habsah
Biomolecular Research Group, Biochemistry Program, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.
Molecules. 2016 Mar 21;21(3):385. doi: 10.3390/molecules21030385.
Deoxyelephantopin (DET), one of the major sesquiterpene lactones derived from Elephantopus scaber was reported to possess numerous pharmacological functions. This study aimed to assess the apoptosis inducing effects and cell cycle arrest by DET followed by elucidation of the mechanisms underlying cell death in HCT116 cells. The anticancer activity of DET was evaluated by a MTT assay. Morphological and biochemical changes were detected by Hoescht 33342/PI and Annexin V/PI staining. The results revealed that DET and isodeoxyelephantopin (isoDET) could be isolated from the ethyl acetate fraction of E. scaber leaves via a bioassay-guided approach. DET induced significant dose- and time-dependent growth inhibition of HCT116 cells. Characteristics of apoptosis including nuclear morphological changes and externalization of phosphatidylserine were observed. DET also significantly resulted in the activation of caspase-3 and PARP cleavage. Additionally, DET induced cell cycle arrest at the S phase along with dose-dependent upregulation of p21 and phosphorylated p53 protein expression. DET dose-dependently downregulated cyclin D1, A2, B1, E2, CDK4 and CDK2 protein expression. In conclusion, our data showed that DET induced apoptosis and cell cycle arrest in HCT116 colorectal carcinoma, suggesting that DET has potential as an anticancer agent for colorectal carcinoma.
去氧地胆苦素（DET）是地胆草中主要的倍半萜内酯之一，据报道具有多种药理功能。本研究旨在评估DET诱导的细胞凋亡作用和细胞周期阻滞，并阐明HCT116细胞死亡的潜在机制。通过MTT法评估DET的抗癌活性。采用Hoescht 33342/PI和Annexin V/PI染色检测形态学和生化变化。结果表明，通过生物活性导向法可从地胆草叶的乙酸乙酯部位分离得到DET和异去氧地胆苦素（isoDET）。DET对HCT116细胞具有显著的剂量和时间依赖性生长抑制作用。观察到细胞凋亡的特征，包括核形态变化和磷脂酰丝氨酸外化。DET还显著导致caspase-3激活和PARP裂解。此外，DET诱导细胞周期阻滞于S期，并伴随p21和磷酸化p53蛋白表达的剂量依赖性上调。DET剂量依赖性地下调细胞周期蛋白D1、A2、B1、E2、CDK4和CDK2蛋白表达。总之，我们的数据表明，DET诱导HCT116结肠癌细胞凋亡和细胞周期阻滞，提示DET有潜力作为一种结肠癌抗癌剂。
