Zare-Mirakabadi Abbas, Sarzaeem Ali, Moradhaseli Saeed, Sayad Aida, Negahdary Masoud
Dept. of Venomous Animals and Antivenom Production, Razi Vaccine and Serum Research Institute, Karaj, Iran.
Dept. of Venomous Animals and Antivenom Production, Razi Vaccine and Serum Research Institute, Karaj, Iran ; Dept. of Biology, Payam-e-Noor University, Tehran, Iran.
Iran J Cancer Prev. 2012 Summer;5(3):109-16.
Functional defects in mitochondria are involved in the induction of cell death in cancer cells. The process of programmed cell death may occur through the mechanisms of apoptosis. Several potential lead molecules such as Camptothecin (CPT) and its analogues have been isolated from plants with anticancer effect. The aim of the present study was to understand the necrotic effect versus apoptotic nature of CPT in HeLa cancer cells.
The anti-proliferative activity of CPT was estimated through 3-(4, 5- Dimethyl Thiazol-2-yl)-2, 5-diphenyl Tetrazolium bromide (MTT) assay and DNA fragmentation analysis using gel electrophoresis. Lactate Dehydrogenase (LDH) activity and cell morphology were assessed under control and CPT exposed conditions to evaluate the necrotic effect of CPT.
The results showed that CPT inhibited the proliferation of HeLa cells in a dose-dependent manner with an Inhibitory Concentration 50% (IC50) of 0.08±0.012 µg/ml. However the significant (p<0.05) increase happens in LDH activity at concentrations 1×10(-1)µg/ml and above. Morphological changes showed that CPT in low concentrations induced an apoptotic mechanism of cell death, such as cell shrinkage and characteristic rounding of dying cells, while at high concentrations showed necrosis changes. The characteristic DNA ladder formation of CPT-treated cells in agarose gel electrophoresis confirmed the results obtained by light microscopy and LDH assay.
Camptothecin as an anticancer drug may have anti-proliferative effect on HeLa cancer cells in low concentrations, through its nature of induction of apoptosis. The border line between necrotic effect and apoptotic nature of CPT in HeLa cancer cells has been found to be at concentration of 1×10(-1) µg/ml.
线粒体功能缺陷参与癌细胞的细胞死亡诱导过程。程序性细胞死亡过程可能通过凋亡机制发生。几种潜在的先导分子，如喜树碱（CPT）及其类似物已从具有抗癌作用的植物中分离出来。本研究的目的是了解CPT对HeLa癌细胞的坏死作用与凋亡性质。
通过3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐（MTT）法和使用凝胶电泳的DNA片段分析来评估CPT的抗增殖活性。在对照和CPT暴露条件下评估乳酸脱氢酶（LDH）活性和细胞形态，以评估CPT的坏死作用。
结果表明，CPT以剂量依赖性方式抑制HeLa细胞的增殖，半数抑制浓度（IC50）为0.08±0.012μg/ml。然而，在浓度为1×10（-1）μg/ml及以上时，LDH活性显著（p<0.05）增加。形态学变化表明，低浓度的CPT诱导细胞死亡的凋亡机制，如细胞收缩和垂死细胞的特征性变圆，而高浓度时则显示坏死变化。琼脂糖凝胶电泳中CPT处理细胞的特征性DNA梯状条带形成证实了通过光学显微镜和LDH测定获得的结果。
喜树碱作为一种抗癌药物，在低浓度下可能通过诱导凋亡的性质对HeLa癌细胞具有抗增殖作用。已发现CPT对HeLa癌细胞的坏死作用和凋亡性质之间的界限浓度为1×10（-1）μg/ml。
