Expression and the role of nuclear matrix protein HMGI (Y) in human renal cell carcinoma

为了检测抗人HMGI(Y)抗体的特异性，我们用小鼠前列腺癌移植瘤模型进行了HMGI(Y)的免疫组织化学染色。在Western印迹分析中，用从PC3细胞中提取的核蛋白检测HMGI(Y)。虽然HMGI(Y)是一种核基质蛋白，但它在胞核和胞浆中均有染色。因此，免疫组织化学方法被认为不适合于检测手术切除标本中HMGI(Y)的表达。另一方面，聚合酶链式反应在所有肾癌细胞系(NC65、ACHN、OUR10、CAKI-L)中均显示与HMGI(Y)基因扩增产物相对应的164个碱基对条带。然后，我们检测了实时荧光聚合酶链式反应以定量检测HMGI(Y)在这些肾癌细胞系中的表达。该方法还检测了其在手术切除的新鲜冰冻组织中的表达。有趣的是，HMGI(Y)在癌组织中的表达比在正常肾组织中更丰富。此外，其在癌组织中的表达高于同一患者的正常组织。在T2-3肿瘤患者的癌组织中，HMGI(Y)的表达高于T1肿瘤患者的癌组织。探讨HMGI(Y)在肾癌中表达作为预后因素的可能性。HMGI(Y)高表达患者的生存期明显长于HMGI(Y)低表达患者，因此，HMGI(Y)在肾癌中的表达可能是一个可能的预后因素。

To examine the specificity of the antibody against human HMGI(Y), we performed immunohistochemical staining of HMGI(Y) using mouse xenograft model of human prostatic cancer. In Western blot analysis, HMGI(Y) was detected using nuclear protein extracted from PC3 cells. Although HMGI(Y) is a nuclear matrix protein, it was stained in nucleus and also in cytosol. Therefore, immunohistochemical approach was not thought to be appropriate to examine the expression of HMGI(Y) in surgical resected specimens. On the other hand, polymerase chain reaction showed 164 base pair band corresponding to PCR product of HMGI(Y) in all renal cancer cell lines (NC65, ACHN, OUR10, Caki-l). Then, we examined real-time PCR for quantify HMGI(Y) expression in these renal cancer cell lines. This method also detected its expression in freshly-frozen tissues which were surgically resected. Interestingly, the expression of HMGI(Y) in cancer tissues was more abundant than in normal renal tissues. Moreover, its expression in cancer tissues was higher than in normal tissues from the same patients. In cancer tissues from patients with T2-3 tumor HMGI(Y) expressed more intensively than in cancer tissues of T1 tumor. The possibility for prognostic factor of the expression of HMGI(Y) in renal cancer was examined. Patients with high expression of HMGI(Y) tend to live longer than those with low expression.Therefore, the expression of HMGI(Y) in renal cell carcinoma may be a possible candidate as a prognostic factor.