Ho Yuan-Soon, Wu Chih-Hsiung, Chou Hsiao-Min, Wang Ying-Jan, Tseng How, Chen Chien-Ho, Chen Li-Ching, Lee Chia-Hwa, Lin Shyr-Yi
Graduate Institute of Biomedical Technology, Taipei Medical University, Taipei 110, Taiwan.
Food Chem Toxicol. 2005 Oct;43(10):1483-95. doi: 10.1016/j.fct.2005.04.002.
Econazole (Eco), a potent broad-spectrum anti-fungal agent, has been used in the treatment of superficial mycosis. Eco is a store-operated Ca2+ channel antagonist which induces cytotoxic cell death of leukemia. However, little is known about its cytotoxic effect upon solid tumor cells. The purpose of this study is to investigate both the in vitro and in vivo molecular mechanisms of Eco-induced toxicity on colon cancer cells. We used COLO 205 cell line and nude mice xenograft model to investigate the cytotoxic effect of Eco. We demonstrated that lower doses Eco (5-20 microM) arrested human colon cancer cells at the G0/G1 phase of the cell cycle. The protein levels of p53, p21/Cip1, and p27/Kip1 were significantly elevated while CDK2 and CDK4 kinase activity were significantly suppressed by Eco treatment in COLO 205 cells. At higher doses (40-60 microM), Eco induced COLO 205 cells apoptosis evidenced by ladder formation in DNA fragmentation assay and sub-G1 peak in flow cytometry analysis. Western blot analysis showed that caspases 3, 9 but not 8 were activated by high dose Eco treatment to the COLO 205 cells accompanied with cytochrome c and apoptosis-inducing factor (AIF) translocation. Significant anti-tumorigenesis effect was further demonstrated in vivo by treating nude mice bearing COLO 205 tumor xenografts with Eco 50 mg/kg intraperitoneally. Our findings highlight the molecular mechanisms underlying the Eco-induced toxicity on colon cancer cells.
益康唑（Eco）是一种强效的广谱抗真菌剂，已用于治疗浅表真菌病。Eco是一种储存性钙通道拮抗剂，可诱导白血病细胞发生细胞毒性死亡。然而，关于其对实体瘤细胞的细胞毒性作用知之甚少。本研究的目的是探讨Eco诱导的对结肠癌细胞毒性的体外和体内分子机制。我们使用COLO 205细胞系和裸鼠异种移植模型来研究Eco的细胞毒性作用。我们证明，较低剂量的Eco（5-20微摩尔）可使人类结肠癌细胞停滞于细胞周期的G0/G1期。在COLO 205细胞中，Eco处理可使p53、p21/Cip1和p27/Kip1的蛋白水平显著升高，而CDK2和CDK4激酶活性则受到显著抑制。在较高剂量（40-60微摩尔）时，Eco诱导COLO 205细胞凋亡，这在DNA片段化分析中的梯状条带形成和流式细胞术分析中的亚G1峰中得到证实。蛋白质印迹分析表明，高剂量Eco处理COLO 205细胞可激活caspases 3、9而非caspases 8，并伴有细胞色素c和凋亡诱导因子（AIF）易位。通过给携带COLO 205肿瘤异种移植的裸鼠腹腔注射50毫克/千克的Eco，进一步在体内证明了显著的抗肿瘤作用。我们的研究结果突出了Eco诱导的对结肠癌细胞毒性的分子机制。
