The Key Laboratory of Forest Plant Ecology, Northeast Forestry University, Ministry of Education, Harbin 150040, China.
Molecules. 2011 Sep 13;16(9):7803-14. doi: 10.3390/molecules16097803.
Camptothecin-20(s)-O-[N-(3'α,12'α-dihydroxy-24'-carbonyl-5'β-cholan)]-lysine (B2) is a novel camptothecin analogue. Our previous study had shown that it displayed higher cytoxicity activity towards hepatocellular carcinoma SMMC-7721 cells than camptothecin (CPT) in vitro. In this paper, the underlying mechanism of anti-proliferation of B2 towards SMMC-7721 cells was further examined. Cell growth inhibition of B2 was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; morphological changes were observed under Laser Scanning Confocal Microscope (LSCM); cell cycle distribution, apoptotic population, changes in mitochondrial membrane potential, intracellular calcium concentration and reactive oxygen species (ROS) production were determined by flow cytometry (FCM). Activities of caspase-3 and caspase-9 were measured, and the expression level of Bcl-2 and Bax proteins were analyzed by Western blot. The results suggested that B2 inhibited SMMC-7721 cell growth by causing cell cycle arrest at the S and G2/M phases, and induced apoptosis involving a mitochondrial pathway. B2 appears to cause a high induction of apoptosis on SMMC-7721 cells in vitro, which suggests it might be a potential drug for cancer therapy.
喜树碱-20(s)-O-[N-(3'α,12'α-二羟基-24'-羰基-5'β-胆烷)]-赖氨酸（B2）是一种新型喜树碱类似物。我们之前的研究表明，它在体外对肝癌 SMMC-7721 细胞的细胞毒性活性比喜树碱（CPT）更高。在本文中，进一步研究了 B2 对 SMMC-7721 细胞的抗增殖作用的潜在机制。使用 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）测定 B2 的细胞生长抑制作用；通过激光共聚焦显微镜（LSCM）观察形态变化；通过流式细胞术（FCM）测定细胞周期分布、凋亡群体、线粒体膜电位变化、细胞内钙离子浓度和活性氧（ROS）产生。测量 caspase-3 和 caspase-9 的活性，并通过 Western blot 分析 Bcl-2 和 Bax 蛋白的表达水平。结果表明，B2 通过使 SMMC-7721 细胞周期停滞在 S 和 G2/M 期来抑制细胞生长，并诱导涉及线粒体途径的细胞凋亡。B2 似乎在体外对 SMMC-7721 细胞有很高的诱导凋亡作用，这表明它可能是一种有潜力的癌症治疗药物。
