School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, PR China.
Chem Biol Interact. 2011 Apr 25;190(2-3):91-101. doi: 10.1016/j.cbi.2011.02.026. Epub 2011 Mar 3.
Hyperforin is an abundant phloroglucinol-type constituent isolated from the extract of the flowering upper portion of the plant Hypericum perforatum L. The dicyclohexylammonium salt of hyperforin (DCHA-HF) has exhibited antitumor and antiangiogenic activities in various cancer cells. Here, the antitumor effects of DCHA-HF on the chronic myeloid leukemia K562 cell line were investigated for the first time. DCHA-HF exhibited dose- and time-dependent inhibitory activities against K562 cells, with IC(50) values of 8.6 and 3.2 μM for 48 h and 72 h of treatment, respectively, which was more effective than that of the hyperforin. In contrast, little cytotoxic activity was observed with DCHA-HF on HUVECs. DCHA-HF treatment resulted in induction of apoptosis as evidenced from DNA fragmentation, nuclear condensation and increase of early apoptotic cells by DAPI staining analysis, TUNEL assay and Annexin V-FITC/PI double-labeled staining analysis, respectively. Moreover, DCHA-HF elicited dissipation of mitochondrial transmembrane potential that commenced with the release of cytochrome c through down-regulation of expression of anti-apoptotic proteins and up-regulation of expression of pro-apoptotic proteins. DCHA-HF treatment induced activation of the caspase 3, 8, and 9 cascade and subsequent PARP cleavage, and DCHA-HF-induced apoptosis was significantly inhibited by caspase inhibitors. Treated cells were arrested at the G1 phase of the cell cycle and the expression of p53 and p27(Kip1), two key regulators related to cell cycle and apoptosis, was up-regulated. These results suggest that DCHA-HF inhibits K562 cell growth by inducing caspase-dependent apoptosis mediated by a mitochondrial pathway and arresting the cell cycle at the G1 phase. Therefore, DCHA-HF is a potential chemotherapeutic antitumor drug for chronic myeloid leukemia therapy.
金丝桃素是贯叶连翘提取物中含量丰富的邻苯二酚型化合物。金丝桃素的二环己基铵盐（DCHA-HF）在各种癌细胞中表现出抗肿瘤和抗血管生成活性。在这里，首次研究了 DCHA-HF 对慢性髓性白血病 K562 细胞系的抗肿瘤作用。DCHA-HF 对 K562 细胞表现出剂量和时间依赖性的抑制活性，其 IC50 值分别为 8.6 和 3.2 μM，分别在 48 h 和 72 h 时达到，其效果优于金丝桃素。相比之下，DCHA-HF 对 HUVECs 的细胞毒性作用较小。DCHA-HF 处理导致细胞凋亡，如 DNA 片段化、核浓缩以及 DAPI 染色分析、TUNEL 测定和 Annexin V-FITC/PI 双标记染色分析分别显示的早期凋亡细胞增加所证明的。此外，DCHA-HF 通过下调抗凋亡蛋白的表达和上调促凋亡蛋白的表达，引起线粒体跨膜电位耗散，从而导致细胞色素 c 的释放。DCHA-HF 处理诱导 caspase 3、8 和 9 级联的激活和随后的 PARP 裂解，并且 caspase 抑制剂显著抑制了 DCHA-HF 诱导的细胞凋亡。处理后的细胞被阻滞在细胞周期的 G1 期，并且与细胞周期和凋亡相关的两个关键调节因子 p53 和 p27(Kip1)的表达上调。这些结果表明，DCHA-HF 通过诱导 caspase 依赖性凋亡来抑制 K562 细胞的生长，该凋亡由线粒体途径介导，并将细胞周期阻滞在 G1 期。因此，DCHA-HF 是一种用于慢性髓性白血病治疗的有潜力的化疗抗肿瘤药物。
