姜黄素的抗胰腺癌作用及相关机制研究

The Anti-Tumor Effect and Mechanism of Curcumin in Pancreatic Cancer

目的探讨姜黄素(curcumin)的抗胰腺癌作用及其可能的机制。方法采用免疫组化法检测35例胰腺癌组织及相邻非癌组织中Smad4、Jab1的表达情况,并从中抽取21例胰腺癌组织测定Jab1与Smad4染色的阳性细胞百分比,分析两者相关性。将人胰腺癌细胞系PANC-1细胞分为PANC-1对照组(不做处理)和PANC-1 cur-cumin组(含10μmol/L姜黄素的细胞培养液处理),采用Western Blot检测姜黄素对肿瘤抑制物p53、Smad4及细胞循环抑制剂p27蛋白表达的影响。将人胚肾细胞系293T细胞分为293T对照组(不做处理)、293T curcumin组(含10μmol/L姜黄素的细胞培养液处理)和293T Jab1组(转染HA-Jab1质粒),采用免疫共沉淀法检测姜黄素对β-Tr CP1与Smad4结合的蛋白表达影响。结果与相邻非癌组织比较,胰腺癌组织中Smad4呈低表达,Jab1呈高表达(均P<0.01),Jab1与Smad4的表达呈负相关(n=21,r=-0.71,P=0.007)。姜黄素可增加PANC-1细胞中Smad4、p53和p27蛋白表达的水平,降低293T细胞中β-Tr CP1与Smad4结合的蛋白表达水平;Jab1可增加293T细胞中β-Tr CP1与Smad4结合的蛋白表达水平(均P<0.05)。结论姜黄素可能通过上调Smad4、p53和p27的蛋白表达进而起到抗胰腺癌作用,其上调Smad4表达的机制可能与其抑制Smad4蛋白的泛素化进程有关,而Jab1也可能通过参与Smad4的泛素化进程影响Smad4蛋白降解。

Objective To investigate the anti-tumor effect and mechanism of curcumin in pancreatic cancer（PC）.Methods Smad4 and Jab1 expressions were detected by immunohistochemistry in tumor tissues and pericarcinomatous tissue from 35 PC cases, and the correlation of Smad4 and Jab1 were analyzed based on the percentage of positive staining intissues from 21 random selected PC cases. The effect of curcumin on expressions of tumor suppressors p53, Smad4 and cell cycle inhibitor p27 were examined by Western Blotting after human pancreatic cancer cell line PANC-1 were divided into PANC-1 control group（no treatments were given） and PANC-1 curcumin group（treated with cell culture medium containing10 μmol/L curcumin）. The effect of curcumin on expressions of combination of β-Tr CP1 and Smad4 was examined by CoImmunoprecipitation after human embryonic kidney cell line 293 T were divided into 293 T control group（no treatments were given）, 293 T curcumin group（treated with cell culture medium containing 10 μmol/L curcumin） and 293 T Jab1 group（transfected by HA-Jab1 plasmid）. Results Compared with expressions in pericarcinomatous tissues, Smad4 was down regulated while the expression of Jab1 was upregulated in PC tissues（P〈0.01）, and the expression of Smad4 was negatively correlated with the expression of Jab1（n=21, r=-0.71, P=0.007）. After treated with curcumin, the protein expression of p53, Smad4and p27 was increased in PANC1 cell, and the protein expression of the combination of β-Tr CP1 and Smad4 was decreased in 293 T cell（P〈0.05）. After transfected by HA-Jab1 plasmid, the protein expression of the combination of β-Tr CP1 and Smad4 was increased in 293 T cell（P〈0.05）. Conclusion Curcumin may have suppression effect of PC through increasing the protein expression of p53, Smad4 and p27, and the mechanism of Smad4 upregulation may be related with the inhibition of Smad4 ubiquitination process, while Jab1 may be also involved in Smad4 degradation through ubiquitination.