Departamento de Bioquímica, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Av, 28 de Setembro 87, fds, PAPC, Vila Isabel, Rio de Janeiro, RJ, CEP 20551-030, Brazil.
BMC Complement Altern Med. 2012 Nov 27;12:231. doi: 10.1186/1472-6882-12-231.
Plant derived compounds have been shown to be important sources of several anti-cancer agents. As cell cycle deregulation and tumor growth are intimately linked, the discovery of new substances targeting events in this biochemical pathway would be of great value. The anti-leukemic effect of an ethanolic extract of Pterodon pubescens seeds (EEPp) has been previously demonstrated and now we show that a terpenic subfraction (SF5) of EEPp containing farnesol, geranylgeraniol and vouacapan derivatives induces apoptosis in the human chronic myelogenous leukemia cell line K562. This work addresses SF5's antiproliferative mechanisms in these cells since they are still unclear.
DNA synthesis in K562 cells was assessed by [3H]-methyl-thymidine incorporation and cell cycle status by flow cytometry. The expression of cyclins D1 and E2, of the cell cycle inhibitor p21 and of the proto-oncogene c-myc was evaluated by semi-quantitative RT-PCR. Extracellular-signal-regulated kinases (ERK) 1/2 and nuclear factor kappa B (NF-κB) activation was evaluated by western blotting.
In K562 cells, SF5 treatment induced a higher inhibition of DNA synthesis and cell growth than the original EEPp hexanic fraction from which SF5 originated, and also arrested the cell cycle in G1. Exposure of these cells to SF5 led to a decrease in cyclin E2 and c-myc expression while p21 mRNA levels were increased. Furthermore, SF5 inhibited the activation of mitogen-activated protein kinase (MAPK) ERK 1/2 and NF-κB.
This work suggests that the anti-leukemic action of SF5 is linked to the inhibition of ERKs, NF-κB and c-myc signaling pathways resulting in reduced cyclin E2 mRNA expression and cell cycle arrest in the G1 phase.
植物衍生化合物已被证明是多种抗癌药物的重要来源。由于细胞周期失调与肿瘤生长密切相关，因此发现靶向该生化途径中事件的新物质将具有重要价值。先前已经证明，羽扇豆种子的乙醇提取物（EEPp）具有抗白血病作用，现在我们表明 EEPp 的萜烯亚组分（SF5）含有法呢醇、香叶基香叶醇和 vouacapan 衍生物，可诱导人慢性髓系白血病细胞系 K562 细胞凋亡。这项工作研究了 SF5 在这些细胞中的抗增殖机制，因为这些机制尚不清楚。
通过 [3H]-甲基胸苷掺入法评估 K562 细胞中的 DNA 合成，通过流式细胞术评估细胞周期状态。通过半定量 RT-PCR 评估细胞周期抑制剂 p21 和原癌基因 c-myc 的表达。通过 Western blot 评估细胞外信号调节激酶 (ERK) 1/2 和核因子 kappa B (NF-κB) 的激活。
在 K562 细胞中，SF5 处理比其原始来源的 EEPp 己烷部分更高地抑制 DNA 合成和细胞生长，并使细胞周期停滞在 G1 期。这些细胞暴露于 SF5 导致细胞周期蛋白 E2 和 c-myc 表达降低，而 p21 mRNA 水平增加。此外，SF5 抑制丝裂原激活蛋白激酶 (MAPK) ERK 1/2 和 NF-κB 的激活。
这项工作表明，SF5 的抗白血病作用与抑制 ERK、NF-κB 和 c-myc 信号通路有关，导致 cyclin E2 mRNA 表达降低和细胞周期停滞在 G1 期。
