胰腺癌中Ring1B、LSD1及P16表达及其与预后的关系

Expressions of Ring1B, LSD1 and P16 in pancreatic cancer and their prognostic impacts

目的:探讨胰腺癌中E3泛素连接酶亚单位Ring1B、组蛋白赖氨酸特异性去甲基化酶1(LSD1)及细胞周期调节因子P16表达与及其与患者预后的关系。方法:用免疫组化法检测85例胰腺癌患者手术标本(癌组织与癌旁组织)中LSD1、Ring1B与P16蛋白的表达及分布,并选取其中6对癌组织和癌旁组织,用qRT-PCR和Western blot法检测mRNA和蛋白表达;分析三者在胰腺癌组织中表达的相关性,及其与患者生存的关系。结果:免疫组化结果显示,Ring1B与LSD1蛋白主要表达于细胞浆,P16主要表达于胞核;Ring1B与LSD1在胰腺癌组织中表达明显高于癌旁组织,而P16的表达明显低于癌旁组织(均P<0.05);在胰腺癌组织中Ring1B、LSD1的表达与P16的表达均呈负相关(r=-476;r=-0.673,均P<0.05)。qRTPCR结果显示,胰腺癌组织中Ring1B和LSD1的mRNA的平均相对表达量均明显高于癌旁组织(8.908vs.1.947;7.126 vs.1.940,均P<0.05),P16的mRNA的平均相对表达量明显低于癌旁组织(1.269vs.5.237,P<0.05);Western blot结果显示,三者的蛋白表达趋势与mRNA表达一致。生存分析显示,Ring1B、LSD1高表达患者生存率均分别低于其低表达患者(χ~2=8.958,P=0.012;χ~2=8.856,P=0.010),而P16高表达患者生存率高于其低表达患者(χ~2=7.867,P=0.024)。结论:胰腺癌组织中Ring1B与LSD1表达升高,P16表达降低;Ring1B、LSD1可能分别通过组蛋白泛素化和去甲基化调控P16的表达,从而影响胰腺癌预后。

Objective： To investigate the expressions of the E3-ubiquitin ligase subunit Ring1B, lysine-specific histone demethylase 1 （LSD1） and cell cycle regulatory molecule P16 in pancreatic cancer and their relations with the prognosis of the patients. Methods： The distributions and expressions of Ring1B LSD1 and P16 proteins in the surgical specimens （cancer tissues and cancer-adjacent tissues） from 85 pancreatic cancer patients were determined by immunohistochemical staining, from which, 6 paired specimens were picked up for measurement of mRNA and protein expressions of Ring1B, LSD1 and P16 through qRT-PCR and Western blot, respectively. The correlations among their expressions in pancreatic cancer tissue, and relations of their expressions with the survival of the patients were analyzed. Results： The results of immunohistochemical staining showed that Ring1B and LSD1 were mainly expressed in the cytoplasm, while P16 protein was mainly found in the nucleus; the Ring1B and LSD1 expressions were significantly higher, while the P16 expression was significantly lower in pancreatic cancer tissue than those in cancer-adjacent tissue （all P〈0.05）; either the Ring1B or LSD1 expression had a negative correlation with P16 expression in pancreatic cancer （r=–476; r=–0.673, both P〈0.05）. The results of qRT-PCR showed that the average relative mRNA expression levels of Ring1B and LSD1 were significantly higher （8.908 vs. 1.947; 7.126 vs. 1.940, both P〈0.05） and the average relative mRNA expression level of P16 in pancreatic cancer tissue was significantly lower （1.269 vs. 5.237, P〈0.05） than those in cancer-adjacent tissue; the protein expression patterns of them were similar to their mRNA expressions as evidenced by Western blot analysis. The survival analysis showed that the survival rate in patients with high Ring1B or LSD1 expression was significantly lower than that in patients with low Ring1B or LSD1 expression （χ2=8.958, P=0.012; χ2=8.856, P=0.010）, which in patients with high P16 expression was significantly higher than that in patients with low P16 expression （χ2=7.867, P=0.024）. Conclusion： Ring1B and LSD1 expressions are increased and P16 expression is decreased in pancreatic cancer tissue. Ring1B and LSD1 may probably regulate P16 expression respectively through histone ubiquitination and demethylation, and thereby influence the prognosis of pancreatic cancer.