Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, 90, Cumaratunga Munidasa Mawatha, Colombo 03, Sri Lanka.
HEJ Research Institute of Chemistry, University of Karachi, Karachi, Pakistan.
Anticancer Agents Med Chem. 2019;19(3):410-424. doi: 10.2174/1871520619666181128163359.
BACKGROUND/OBJECTIVE: Vernonia zeylanica (L) less is an endemic plant to Sri Lanka. The present study was designed to isolate potential cytotoxic compound/s from chloroform and ethyl acetate extracts of V. zeylanica by bio-activity guided isolation and to evaluate its anti-proliferative effects in three breast cancer phenotypes (MCF -7, MDA-MB-231, SKBR-3).
Combined chloroform and ethyl acetate extracts were subjected to chromatographic separations to isolate a compound (1) and the structure of the isolated compound was elucidated using 1H, 13C and mass spectroscopic techniques. Cytotoxic effects of the compound were evaluated by the sulforhodamine B (SRB) and the MTT (3- (4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays. Effects of the compound on apoptosis were evaluated by fluorescent microscopy, caspase 3/7 activation, DNA fragmentation and real time PCR. Effects of the compound on the expression of heat shock protein complex were also evaluated by real time PCR and immunofluorescence.
Isolated compound was identified as a new sesquiterpene lactone (vernolactone). The compound mediated significant cytotoxic effects in SKBR-3 and MDA-MB-231 breast cancer cells, with little effect in MCF-7 and normal mammary epithelial MCF-10A cells. Morphological changes, DNA fragmentation, increased caspase 3/7 activities and up-regulation of p53, Bax and down regulation of Survivin confirmed the proapoptotic effects of the compound. Significant inhibition of HSP complex related genes were also observed in SKBR-3 and MDA-MB-231 breast cancer cells.
Overall results indicate that vernolactone can mediate its cytotoxic effects via apoptosis and modulating the HSP complex.
背景/目的：泽兰叶（L）是斯里兰卡特有的一种植物。本研究旨在通过生物活性导向分离从泽兰叶的氯仿和乙酸乙酯提取物中分离潜在的细胞毒性化合物，并评估其在三种乳腺癌表型（MCF-7、MDA-MB-231、SKBR-3）中的抗增殖作用。
将氯仿和乙酸乙酯提取物合并进行色谱分离，以分离出一种化合物（1），并使用 1H、13C 和质谱技术阐明分离化合物的结构。采用磺酰罗丹明 B（SRB）和 MTT（3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐）测定法评估化合物的细胞毒性作用。通过荧光显微镜、半胱天冬酶 3/7 激活、DNA 片段化和实时 PCR 评估化合物对细胞凋亡的影响。还通过实时 PCR 和免疫荧光评估化合物对热休克蛋白复合物表达的影响。
分离出的化合物被鉴定为一种新的倍半萜内酯（vernolactone）。该化合物在 SKBR-3 和 MDA-MB-231 乳腺癌细胞中具有显著的细胞毒性作用，而对 MCF-7 和正常乳腺上皮 MCF-10A 细胞的作用较小。形态学变化、DNA 片段化、半胱天冬酶 3/7 活性增加以及 p53、Bax 的上调和 Survivin 的下调证实了该化合物的促凋亡作用。还观察到 SKBR-3 和 MDA-MB-231 乳腺癌细胞中 HSP 复合物相关基因的显著抑制。
总体结果表明，vernolactone 可以通过凋亡和调节 HSP 复合物来介导其细胞毒性作用。
