Department of Obstetrics and Gynecology, Yamaguchi University Graduate School of Medicine, Ube 755-8505, Japan.
Int J Oncol. 2010 Jun;36(6):1395-400. doi: 10.3892/ijo_00000624.
Squamous cell carcinoma antigen (SCCA) is a useful tumor marker for diagnosis and management of squamous cell carcinoma. Recent reports have shown that SCCA can influence the invasion or metastasis of cancer cells. However, it remained unclear how SCCA acts to mediate these biological functions. To solve this question, at first, SCCA1- and SCCA2-glutathione S-transferase fusion protein were used to purify a protein which binds to SCCA1 or SCCA2, and the combined protein was identified by proteomic analysis. Secondly, immunocytochemical and immunohistochemical analyses were performed to investigate the localization of this protein. Third, Western blotting was performed to analyze the expression levels of this protein in keratinocytes and six kinds of uterine squamous cell carcinoma cell lines. Both SCCA1 and SCCA2 molecules bind to the cytoplasmic protein, which was identified to be carbonyl reductase (CR). The immunostaining analyses revealed that CR is located in the cytoplasm of keratinocytes and the normal squamous epithelial cells of the uterine cervix as well as SCCA1 and SCCA2. The CR expression levels in six kinds of squamous cell carcinoma cell lines were lower compared to those in keratinocytes. In conclusion, CR binds to SCCA1 and SCCA2 and they are co-located in the same layer of the squamous epithelium, suggesting that CR may collaborate with SCCA1 and SCCA2 to mediate cancer behavior such as invasion or metastasis.
鳞状细胞癌抗原 (SCCA) 是诊断和治疗鳞状细胞癌的有用肿瘤标志物。最近的报告表明，SCCA 可以影响癌细胞的侵袭或转移。然而，SCCA 如何发挥作用来介导这些生物学功能仍不清楚。为了解决这个问题，首先使用 SCCA1 和 SCCA2-谷胱甘肽 S-转移酶融合蛋白来纯化与 SCCA1 或 SCCA2 结合的蛋白，然后通过蛋白质组学分析鉴定结合蛋白。其次，进行免疫细胞化学和免疫组织化学分析以研究该蛋白的定位。第三，进行 Western blot 分析以分析该蛋白在角质形成细胞和六种子宫鳞状细胞癌细胞系中的表达水平。SCCA1 和 SCCA2 分子都与细胞质蛋白结合，该蛋白被鉴定为羰基还原酶 (CR)。免疫染色分析表明，CR 位于角质形成细胞和子宫颈的正常鳞状上皮细胞以及 SCCA1 和 SCCA2 中。六种鳞状细胞癌细胞系中的 CR 表达水平低于角质形成细胞。总之，CR 与 SCCA1 和 SCCA2 结合，并且它们在鳞状上皮的同一层中共定位，表明 CR 可能与 SCCA1 和 SCCA2 合作来介导侵袭或转移等癌症行为。
