Hung Wen-Chun, Chang Hui-Chiu
School of Technology for Medical Sciences, Kaohsiung Medical University, Kaohsiung 807, Taiwan, Republic of China.
J Agric Food Chem. 2003 Dec 3;51(25):7333-7. doi: 10.1021/jf0340512.
Previous results demonstrated that the methanolic extract of adlay seed exerted an antiproliferative effect on human lung cancer cells in vitro and in vivo and might prevent tobacco carcinogen-induced lung tumorigenesis. In this study, the methanolic extract of adlay seed was tested for its regulation of COX-2 expression of human lung cancer cells. Western blot analysis showed that the methanolic extract of adlay seed inhibited basal and TPA-induced COX-2 expression in a dose-dependent fashion, whereas COX-1 expression was not affected. By using a promoter activity assay, it was found that the methanolic extract inhibited basal and TPA-stimulated COX-2 expression at the transcription level. The effect of the methanolic extract on COX-2 expression in vivo was then investigated. The data demonstrated that treatment of the methanolic extract reduced the PGE(2) level in serum and inhibited COX-2 expression of tumor tissues in nude mice. Taken together, these results suggest that inhibition of COX-2 is one of the mechanisms by which the methanolic extract of adlay seed inhibits cancer growth and prevents lung tumorigenesis.
先前的研究结果表明，薏仁种子的甲醇提取物在体外和体内对人肺癌细胞均具有抗增殖作用，并且可能预防烟草致癌物诱导的肺癌发生。在本研究中，对薏仁种子的甲醇提取物调节人肺癌细胞COX-2表达的作用进行了检测。蛋白质免疫印迹分析表明，薏仁种子的甲醇提取物以剂量依赖性方式抑制基础状态和佛波酯（TPA）诱导的COX-2表达，而COX-1表达未受影响。通过启动子活性分析发现，甲醇提取物在转录水平抑制基础状态和TPA刺激的COX-2表达。随后研究了甲醇提取物在体内对COX-2表达的影响。数据表明，给予甲醇提取物可降低裸鼠血清中前列腺素E2（PGE2）水平，并抑制肿瘤组织中COX-2的表达。综上所述，这些结果表明抑制COX-2是薏仁种子甲醇提取物抑制癌症生长和预防肺癌发生的机制之一。
