中文摘要：

目的：探讨磷脂酶D1（PLD1）在不同乳腺癌细胞中的表达情况以及雷公藤甲素（TP）对人乳腺癌细胞PLD1表达的影响.方法：体外培养人乳腺癌细胞MCF7、MDA-MB-231和小鼠乳腺癌细胞4T1,以人乳腺上皮细胞MCF10A为对照,采用半定量RT-PCR测定PLD1 mRNA表达水平,Western blot法测定PLD1蛋白表达水平,并分别测定不同浓度TP对PLD1及细胞周期素D1（cyclin D1）mRNA和蛋白的表达水平的影响.结果：半定量RT-PCR和Western blot分析均显示,PLD1 mRNA和蛋白在乳腺癌细胞MCF7、MDA-MB-231和4T1中的表达显著高于乳腺上皮细胞MCF10A,其中MDA-MB-231细胞PLD1蛋白表达水平约为MCF10A细胞的20倍.TP抑制人乳腺癌细胞MDA-MB-231增殖的同时下调PLD1和cyclin D1表达水平,并且呈一定浓度依赖性.结论：相比乳腺正常上皮细胞,PLD1 mRNA和蛋白在乳腺癌细胞中表达增高,TP抑制乳腺癌细胞增殖的作用机制与其抑制PLD1的表达有关.

英文摘要：

AIM： To investigate the expression of phospholipase D1（ PLD1） in different breast cancer cells and its role in the effects of traditional Chinese medicine triptolide（ TP） on human breast cancer cells. METHODS： The expression levels of PLD1 mRNA and PLD1 protein in human breast epithelial cells and cancer cell lines were determined by RT-PCR and Western Blot.The effect of TP on cancer cell proliferation was examined by MTT assay in MDA-MB-231 cells. Meanwhile,PLD1 and cyclin D1 expression in triptolide-treated human breast cancer cells were also determined by RT-PCR and Western Blot. RESULTS：Expression levels of both PLD1 mRNA and protein were higher in breast cancer cells including MCF7,MDA-MB-231 and 4 T1 than those of normal breast epithelial cell（ MCF10 A）,with expression level of PLD1 protein in MDA-MB-231 cell roughly 20 times that of MCF10 A cells. Furthermore,expression of PLD1 and cyclin D1 reduced while MDA-MB-231 cell proliferation was inhibited by TP treatment. CONCLUSION： Higher expression of PLD1 in human MDA-MB-231 breast cancer cells is associated with its role in the development and progression of breast cancer. TP down-regulated PLD1 expression in the breast cancer cell line,which provides evidence for developing PLD1-targeted therapeutics for breast cancer with high expression of PLD1.