Department of Pathology, University of Otago, Dunedin, New Zealand.
PLoS One. 2011;6(6):e20603. doi: 10.1371/journal.pone.0020603. Epub 2011 Jun 10.
The literature concerning the subcellular location of Y-box binding protein 1 (YB-1), its abundance in normal and cancer tissues, and its prognostic significance is replete with inconsistencies. An explanation for this could be due in part to the use of different antibodies in immunohistochemical and immunofluorescent labeling of cells and tissues. The inconsistencies could also be due to poor resolution of immunohistochemical data. We analyzed two cohorts of breast tumours for both abundance and subcellular location of YB-1 using three different antibodies; two targeting N-terminal epitopes (AB-a and AB-b) and another (AB-c) targeting a C-terminal epitope. We also investigated stress-induced nuclear translocation of YB-1 in cell culture. We report that both AB-a and AB-c detected increased YB-1 in the cytoplasm of high-grade breast cancers, and in those lacking estrogen and progesterone receptors; however the amount of YB-1 detected by AB-a in these cancers is significantly greater than that detected by AB-c. We confirm our previously published findings that AB-b is also detecting hnRNP A1, and cannot therefore be used to reliably detect YB-1 by immunohistochemistry. We also report that AB-a detected nuclear YB-1 in some tumour tissues and stress treated cells, whereas AB-c did not. To understand this, cancer cell lines were analyzed using native gel electrophoresis, which revealed that the antibodies detect different complexes in which YB-1 is a component. Our data suggest that different YB-1 antibodies show different staining patterns that are determined by the accessibility of epitopes, and this depends on the nature of the YB-1 complexes. It is important therefore to standardize the protocols if YB-1 is to be used reproducibly as a prognostic guide for different cancers.
有关 Y 盒结合蛋白 1（YB-1）的亚细胞定位、在正常组织和癌症组织中的丰度及其预后意义的文献充满了不一致之处。造成这种情况的一个解释可能部分归因于在细胞和组织的免疫组织化学和免疫荧光标记中使用了不同的抗体。不一致也可能是由于免疫组织化学数据的分辨率较差。我们使用三种不同的抗体分析了两个乳腺癌队列的 YB-1 的丰度和亚细胞定位；两种针对 N 端表位（AB-a 和 AB-b），另一种（AB-c）针对 C 端表位。我们还研究了细胞培养中应激诱导的 YB-1 核易位。我们报告说，AB-a 和 AB-c 都在高级别乳腺癌和缺乏雌激素和孕激素受体的乳腺癌中检测到细胞质中 YB-1 的增加；然而，AB-a 在这些癌症中检测到的 YB-1 量明显大于 AB-c。我们证实了我们之前发表的发现，即 AB-b 也在检测 hnRNP A1，因此不能通过免疫组织化学可靠地检测 YB-1。我们还报告说，AB-a 在一些肿瘤组织和应激处理的细胞中检测到核 YB-1，而 AB-c 则没有。为了理解这一点，使用天然凝胶电泳分析了癌细胞系，结果表明抗体检测到不同的复合物，其中 YB-1 是一个组成部分。我们的数据表明，不同的 YB-1 抗体显示出不同的染色模式，这取决于表位的可及性，而这取决于 YB-1 复合物的性质。因此，如果要将 YB-1 作为不同癌症的预后指南重复使用，则标准化方案非常重要。
