Yedjou Clement G, Tchounwou Paul B
Cellomics and Toxicogenomics Research Laboratory, NIH RCMI-Center for Environmental Health, College of Science, Engineering and Technology, Jackson State University, 1400 Lynch Street, P.O. Box 18540, Jackson, Mississippi, USA.
J Cancer Sci Ther. 2012 Jan 1;2012(Suppl 3):6. doi: 10.4172/1948-5956.S3-006.
Garlic supplementation in diet has been shown to be beneficial to cancer patients. Recently, its pharmacological role in the prevention and treatment of cancer has received increasing attention. However, the mechanisms by which garlic extract (GE) induces cytotoxicity, oxidative stress, and apoptosis in cancer cells remain largely unknown.
The present study was designed to use HL-60 cells as a test model to evaluate whether or not GE-induced cytotoxicty and apoptosis in human leukemia (HL-60) cells is mediated through oxidative stress.
Human leukemia (HL-60) cells were treated with different concentrations of GE for 12 hr. Cell survival was determined by MTT assay. The extent of oxidative cell/tissue damage was determined by measuring malondialdehyde (lipid peroxidation biomarker) concentrations by spectrophotometry. Cell apoptosis was measured by flow cytometry assessment (Annexin-V and caspase-3 assays) and agarose gel electrophoresis (DNA laddering assay).
Data obtained from the MTT assay indicated that GE significantly () reduced the viability of HL-60 cells in a concentration-dependent manner. We detected a significant ( 0.05) increase in malondialdehyde (MDA) concentrations in GE-treated HL-60 cells compared to the control. Flow cytometry data showed a strong concentration-response relationship between GE exposure and Annexin-V positive HL-60 cells. Similarly, a statistically significant and concentration-dependent increase (0.05) were recorded with regard to caspase-3 activity in HL-60 cells undergoing late apoptosis. These results were confirmed by data of DNA laddering assay showing a clear evidence of nucleosomal DNA fragmentation in GE-treated cells.
Our finding indicates that GE-induced cytotoxicity and apoptosis in HL-60 cells involve phosphatidylserine externalization, caspase-3 activation, and nucleosomal DNA fragmentation associated with the formation of MDA, a by-product of lipid peroxidation and biomarker of oxidative stress. At therapeutic concentrations, GE-induced cytotoxic and apoptotic effects in HL-60 cells is mediated by oxidative stress.
饮食中补充大蒜已被证明对癌症患者有益。最近，其在癌症预防和治疗中的药理作用受到越来越多的关注。然而，大蒜提取物（GE）诱导癌细胞产生细胞毒性、氧化应激和凋亡的机制仍 largely 未知。
本研究旨在以 HL-60 细胞为测试模型，评估 GE 诱导人白血病（HL-60）细胞产生细胞毒性和凋亡是否通过氧化应激介导。
用不同浓度的 GE 处理人白血病（HL-60）细胞 12 小时。通过 MTT 法测定细胞存活率。通过分光光度法测量丙二醛（脂质过氧化生物标志物）浓度来确定氧化细胞/组织损伤程度。通过流式细胞术评估（膜联蛋白 V 和半胱天冬酶-3 检测）和琼脂糖凝胶电泳（DNA 梯状条带检测）测量细胞凋亡。
MTT 法获得的数据表明，GE 显著（）以浓度依赖方式降低 HL-60 细胞的活力。与对照组相比，我们检测到 GE 处理的 HL-60 细胞中丙二醛（MDA）浓度显著（0.05）增加。流式细胞术数据显示 GE 暴露与膜联蛋白 V 阳性 HL-60 细胞之间存在强烈的浓度-反应关系。同样，在经历晚期凋亡的 HL-60 细胞中，半胱天冬酶-3 活性在统计学上有显著的浓度依赖性增加（0.05）。DNA 梯状条带检测数据证实了这些结果，显示 GE 处理的细胞中有明显的核小体 DNA 片段化证据。
我们的发现表明，GE 诱导 HL-60 细胞产生细胞毒性和凋亡涉及磷脂酰丝氨酸外化、半胱天冬酶-3 激活以及与 MDA 形成相关的核小体 DNA 片段化，MDA 是脂质过氧化的副产物和氧化应激的生物标志物。在治疗浓度下，GE 诱导 HL-60 细胞产生细胞毒性和凋亡作用是由氧化应激介导的。
