13-甲基十四烷酸诱导前列腺癌DU145细胞凋亡的分子机制

Molecular mechanism of DU145 prostatic cancer cells apoptosis induced by 13-MTD

目的探讨侧链饱和脂肪酸13-甲基十四烷酸（13-MTD）诱导前列腺癌DU145细胞凋亡的分子机制。方法体外培养人前列腺癌DU145细胞，分别用溶剂和140 μg／ml 13-MTD处理，在作用4、8和24h后，用Western blot检测Caspase酶底物多二磷酸腺苷核糖多聚酶（PARP）、核纤层蛋白B受体（Lamin B）以及视母细胞瘤蛋白（Rb）是否断裂，观察Caspase酶抑制剂z—DEYD-fmk和z—YAD—fmk对Caspase酶抑制作用，监测13-MTD处理DU145细胞后是否使线粒体释放细胞色素C至胞浆，最后检测13-MTD对人前列腺正常上皮细胞、人乳腺正常上皮细胞、人皮肤正常角化细胞是否具有诱导凋亡作用。结果经13-MTD处理的前列腺癌细胞，蛋白免疫印迹法检测到Caspase底物Lamin B、Rb以及PARP蛋白出现断裂，该反应可被Caspase抑制剂z—DEVD—fmk和z—VAD—fmk阻止，胞浆中可检测到从线粒体释放的细胞色素C。与前列腺癌细胞不同，经13-MTD处理过的正常前列腺上皮细胞、乳腺上皮细胞及皮肤角化细胞没有出现Caspase底物Lamin B断裂和细胞色素C释放。结论13-MTD能选择性地诱导前列腺癌细胞凋亡而不作用于正常细胞，其凋亡是通过线粒体释放细胞色素C的Caspase依赖性途径。

Objective To investgate the molecular mechanism of DU145 prostatic cancer cells apoptosis induced by 13-MTD. Methods Prostate carcinoma cell line DU145 was treated with solvent or 13-MTD at 140 μg/ ml for 4h, 8h and 24h. Cytosol Cytochrome C released from mitochomdria, cleavage of PARP, Lamin B and Rb proteins were analysed by Western blot. Caspase-dependent analysis were performed with inhibitor z-DEVD-fmk and z-VAD-fmk. 3 kinds of normal epithelial cell lines were treated with 13-MTD compared with DU145, released Cytochrome C and cleavaged of Lamin B were detected by western blot. Result After treatment with 140μg/ml 13- MTD, cytosol Cytochrome C released from mitochondrion could be detected by Western blot, indicating mitochondrion attended the 13-MTD-induced apoptotic in DU145 prostatic cancer cells, which could not be eliminated by Caspase inhibitor z-DEVD-fmk and z-VAD-fmk. Fragmentation of PARP, Rb and Lamin B were detected in the 13-MTD-induced prostatic cancer cells, but not in the 13-MTD-induced normal cells, showing that 13-MTD selectively induced apoptosis for cancer cells and had no effect on normal cells. This reaction could be inhibited by z-DEVD-fmk and z-VAD-fmk, indicating that this 13-MTD-induced apoptotic in DU145 prostatic cancer cells was caspase -dependent. Conclusion 13-MTD induces apoptosis of prostate cancer cell line DU145, not normal human epithelial cell, through mitochondria-attended and Caspase-dependent pathway.