d -Limonene sensitizes docetaxel-induced cytotoxicity in human prostate cancer cells: Generation of reactive oxygen species and induction of apoptosis.
d -Limonene sensitizes docetaxel-induced cytotoxicity in human prostate cancer cells: Generation of reactive oxygen species and induction of apoptosis.
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DOI：
10.4103/1477-3163.51368
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发表时间：
2009
影响因子：
--
通讯作者：
Bishayee A
中科院分区：
文献类型：
--
作者：
Rabi T;Bishayee A
临床试验表明，多西他赛联合其他新药可以提高雄激素非依赖性前列腺癌患者的存活率。D-柠檬烯是一种非营养性饮食成分，已被发现无毒性地抑制各种癌细胞的生长。在转移性前列腺癌的体外模型中，我们试图确定无毒剂量的d-柠檬烯是否可以增强肿瘤对多西紫杉醇的反应。用不同浓度的d-柠檬烯、多西紫杉醇或两者联合作用于人前列腺癌DU-145细胞和正常前列腺上皮PZ-HPV-7细胞，用四甲基偶氮唑盐比色法测定细胞存活率。测定细胞内活性氧(ROS)、还原型谷胱甘肽(GSH)和半胱氨酸天冬氨酸氨基转移酶(Caspase)活性。用酶联免疫吸附试验和Western blotting分别检测细胞凋亡和凋亡相关蛋白的表达。与PZ-HPV-7细胞相比，D-柠檬烯和多西紫杉醇联合应用对DU-145细胞的杀伤作用明显增强。与多西紫杉醇单独作用相比，d-柠檬烯和多西紫杉醇联合作用可导致DU-145细胞产生更高的ROS，消耗GSH，同时caspase活性增加。它还引发了一系列影响，涉及细胞色素c，caspase-9，3和多聚(ADP-核糖)聚合酶的裂解，以及Bad/BCL-XL比率的改变，有利于细胞凋亡。N-乙酰半胱氨酸预处理可显著阻断细胞的凋亡作用，表明抗肿瘤作用是由ROS的产生启动的，caspase级联通路参与了细胞死亡。我们的结果首次表明，d-柠檬烯增强了多西紫杉醇对前列腺癌细胞的抗肿瘤作用，而对正常的前列腺上皮细胞没有毒性。这种联合的有益作用可能是通过调节线粒体凋亡途径中涉及的蛋白质来实现的。D-柠檬烯可以作为一种有效的无毒药物来改善多西紫杉醇治疗激素抵抗型前列腺癌的疗效。
Clinical trials have shown that docetaxel combined with other novel agents can improve the survival of androgen-independent prostate cancer patients. d-Limonene, a non-nutrient dietary component, has been found to inhibit various cancer cell growths without toxicity. We sought to characterize whether a non-toxic dose of d-limonene may enhance tumor response to docetaxel in an in vitro model of metastatic prostate cancer. Human prostate carcinoma DU-145 and normal prostate epithelial PZ-HPV-7 cells were treated with various concentrations of d-limonene, docetaxel or a combination of both, and cell viability was determined by MTT assay. Intracellular reactive oxygen species (ROS), reduced glutathione (GSH) and caspase activity were measured. Apoptosis and apoptosis-related proteins were studied by enzyme-linked immunosorbent assay and Western blotting, respectively. d-Limonene and docetaxel in combination significantly enhanced the cytotoxicity to DU-145 cells than PZ-HPV-7 cells. Exposure of DU-145 cells to a combined d-limonene and docetaxel resulted in higher ROS generation, depletion of GSH, accompanied by increased caspase activity than docetaxel alone. It also triggered a series of effects involving cytochrome c, cleavages of caspase-9, 3 and poly (ADP-ribose) polymerase, and a shift in Bad:Bcl-xL ratio in favor of apoptosis. Apoptotic effect was significantly blocked on pretreatment with N-acetylcystein, indicating that antitumor effect is initiated by ROS generation, and caspase cascades contribute to the cell death. Our results show, for the first time, that d-limonene enhanced the antitumor effect of docetaxel against prostate cancer cells without being toxic to normal prostate epithelial cells. The combined beneficial effect could be through the modulation of proteins involved in mitochondrial pathway of apoptosis. d-Limonene could be used as a potent non-toxic agent to improve the treatment outcome of hormone-refractory prostate cancer with docetaxel.