Rehman I, Cross S S, Azzouzi A-R, Catto J W F, Deloulme J C, Larre S, Champigneuille J, Fromont G, Cussenot O, Hamdy F C
Academic Urology Unit, Division of Clinical Sciences South, University of Sheffield, Floor K, Royal Hallamshire Hospital, Glossop Road, Sheffield S10 2JF, UK.
Br J Cancer. 2004 Aug 16;91(4):739-44. doi: 10.1038/sj.bjc.6602034.
S100A6 (Calcyclin) is a calcium-binding protein that has been implicated in a variety of biological functions as well as tumorigenesis. The aim of our study was to investigate the involvement of S100A6 during prostate cancer development and progression. Using immunohistochemistry, the expression of S100A6 was examined in benign (n=66), premalignant (n=10), malignant (n=66) and metastatic prostate (n=5) tissues arranged in a tissue-microarray or whole sections as well as in prostate cancer cell lines. The S100A6 immunostaining pattern in tissues was compared with that of cytokeratin 5 (a basal cell marker) and 18 (a benign luminal cell marker). In all cases of benign epithelium, intense S100A6 expression was seen in the basal cell layer with absent staining in luminal cells. In all cases of prostatic adenocarcinoma (matched), metastatic lesions and 3/10 high-grade prostatic intraepithelial neoplasia lesions, an absence of S100A6 was seen. Western blotting and RT-PCR analysis of cell lines showed S100A6 expression to be absent in LNCaP, LNCaP-LN3 and LNCaP-Pro5 but present in Du145, PC3, PC-3M and PC-3M-LN4. LNCaP cells treated with 5-Azacytidine, caused re-expression of S100A6 mRNA. Sequencing of bisulphite modified DNA showed CpG methylation within the S100A6 promoter region and exon 1 of LNCaP, LNCaP-LN3 and LNCaP-Pro5 cell lines but not in Du145 cells. Our data suggest that loss of S100A6 protein expression is common in prostate cancer development and may occur at an early stage. The mechanism of loss of expression may involve hypermethylation of CpG sites. The finding of intense S100A6 expression in the basal cells of benign glands but loss of expression in cancer could be useful as a novel diagnostic marker for prostate cancer.
S100A6（钙周期蛋白）是一种钙结合蛋白，与多种生物学功能以及肿瘤发生有关。我们研究的目的是调查S100A6在前列腺癌发生和发展过程中的作用。采用免疫组织化学方法，在组织芯片或全切片上检测了66例良性、10例癌前、66例恶性和5例转移性前列腺组织以及前列腺癌细胞系中S100A6的表达。将组织中的S100A6免疫染色模式与细胞角蛋白5（一种基底细胞标志物）和18（一种良性管腔细胞标志物）的模式进行比较。在所有良性上皮病例中，基底细胞层可见强烈的S100A6表达，管腔细胞无染色。在所有前列腺腺癌（配对）、转移灶以及3/10的高级别前列腺上皮内瘤变病变中，均未见S100A6表达。细胞系的蛋白质印迹和逆转录-聚合酶链反应分析显示，LNCaP、LNCaP-LN3和LNCaP-Pro5细胞系中无S100A6表达，但在Du145、PC3、PC-3M和PC-3M-LN4细胞系中有表达。用5-氮杂胞苷处理LNCaP细胞导致S100A6 mRNA重新表达。亚硫酸氢盐修饰DNA测序显示，LNCaP、LNCaP-LN3和LNCaP-Pro5细胞系的S100A6启动子区域和外显子1内存在CpG甲基化，而Du145细胞中无此现象。我们的数据表明，S100A6蛋白表达缺失在前列腺癌发生过程中很常见，且可能发生在早期。表达缺失的机制可能涉及CpG位点的高甲基化。在良性腺体基底细胞中发现强烈的S100A6表达而在癌组织中表达缺失，这可能作为前列腺癌一种新的诊断标志物。
