Yousef G M, Yacoub G M, Polymeris M-E, Popalis C, Soosaipillai A, Diamandis E P
Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada.
Br J Cancer. 2004 Jan 12;90(1):167-72. doi: 10.1038/sj.bjc.6601451.
Recent evidence suggests that many members of the human kallikrein gene family are differentially regulated in breast cancer and other endocrine-related malignancies. In this study, we utilised the serial analysis of gene expression (SAGE) and expressed sequence tag (EST) databases of the Cancer Genome Anatomy Project (CGAP) to perform in silico analyses of the expression pattern of the 15 human kallikrein genes in normal and cancerous breast tissues and cell lines using different analytical tools such as Virtual Northern blotting, Digital Differential Display and X-profiler. Our results indicate that at least four kallikrein genes (KLK5, 6, 8, 10) are downregulated in breast cancer. Probing eight normal and 24 breast cancer SAGE libraries with gene-specific tags for each of the above kallikreins indicated moderate-to-high expression densities in normal breast (27-319 tags per million; tpm, in two to five out of eight libraries), compared to no or low expression (0 - 34 tpm in zero to two libraries out of 24) in breast cancer. These data were verified by screening the EST databases, where all mRNA clones isolated for these genes, except for one in each, were from normal breast libraries, with no clones detected from breast cancer tissues or cell lines (with the exception of KLK8). X-profiler comparison of two pools of normal and breast cancer libraries further verified the presence of significant downregulation of expression levels of 4 of the kallikreins genes (KLK5, 6, 10, 12). We experimentally verified the downregulation of these four kallikreins (KLK5, 6, 8, 10 and 12) by RT - PCR analysis.
最近的证据表明，人类激肽释放酶基因家族的许多成员在乳腺癌和其他内分泌相关恶性肿瘤中受到不同程度的调控。在本研究中，我们利用癌症基因组解剖计划（CGAP）的基因表达序列分析（SAGE）和表达序列标签（EST）数据库，使用不同的分析工具，如虚拟Northern印迹、数字差异显示和X-profiler，对15个人类激肽释放酶基因在正常和癌性乳腺组织及细胞系中的表达模式进行了电子分析。我们的结果表明，至少有四个激肽释放酶基因（KLK5、6、8、10）在乳腺癌中表达下调。用上述每个激肽释放酶的基因特异性标签探测8个正常乳腺和24个乳腺癌SAGE文库，结果显示正常乳腺中的表达密度为中度至高度（每百万27 - 319个标签；tpm，在8个文库中的2至5个文库中），而在乳腺癌中则无表达或低表达（24个文库中的0至2个文库中为0 - 34 tpm）。通过筛选EST数据库验证了这些数据，其中除每个基因各有一个外，所有分离到的这些基因的mRNA克隆均来自正常乳腺文库，未检测到来自乳腺癌组织或细胞系的克隆（KLK8除外）。对两个正常和乳腺癌文库池进行X-profiler比较，进一步验证了4个激肽释放酶基因（KLK5、6、10、12）的表达水平存在显著下调。我们通过RT - PCR分析实验验证了这四个激肽释放酶（KLK5、6、8、10和12）的下调。
