Laboratory of Biochemistry and Toxicology, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece.
Mamm Genome. 2009 Nov-Dec;20(11-12):758-67. doi: 10.1007/s00335-009-9237-y. Epub 2009 Dec 2.
Human kallikrein-related peptidases are serine proteases, with diverse, yet poorly defined, roles in carcinogenesis. Recently, we have suggested that the dog may represent a suitable animal model for studying kallikrein (KLK) functions in cancer. The initial objective of the present study was to investigate KLK10 expression in cancerous and noncancerous canine mammary tissues. Our results revealed that the in silico predicted canine KLK10 mRNA sequence (GenBank accession No. XM_541467) is not accurate. Specifically, the predicted mRNA harbors a 183-bp segment, which constitutes part of (CANFA)KLK10 intron I, and a 756-bp sequence that corresponds to the nonpreviously characterized (CANFA)KLK9 coding region. In this report we experimentally determined the coding regions of canine KLK9 and KLK10, which were shown to exhibit high homology to their human counterparts and possess all KLK-defining features. For (CANFA)KLK9, other than the classical form of the gene, three more alternatively spliced variants bearing exon 3 skipping and/or intron I retention were identified. The classical form and variant 1 of KLK9, as well as KLK10, were found to be widely expressed among all tissues examined. Lower positivity rates were detected for KLK9 variants 2 and 3. None of these transcripts, however, showed any preferential or differential expression between tumor and normal tissues. Interestingly, (CANFA)KLK9 and (CANFA)KLK10 were concurrently expressed in almost all tissue samples; this suggests a possible participation of these serine proteases in a common proteolytic cascade. Overall, this is the first study that experimentally characterizes canine KLK9 and KLK10 and demonstrates their expression in normal and malignant tissues.
人激肽释放酶相关肽酶是丝氨酸蛋白酶，在肿瘤发生中具有多种但定义不明确的作用。最近，我们提出狗可能是研究激肽（KLK）在癌症中功能的合适动物模型。本研究的最初目的是研究犬科 KLK10 在癌性和非癌性犬乳腺组织中的表达。我们的研究结果表明，计算机预测的犬科 KLK10 mRNA 序列（GenBank 登录号 XM_541467）并不准确。具体而言，预测的 mRNA 包含一个 183 个碱基的片段，该片段构成部分（CANFA）KLK10 内含子 I，以及一个 756 个碱基的序列，对应于以前未表征的（CANFA）KLK9 编码区。在本报告中，我们实验确定了犬科 KLK9 和 KLK10 的编码区，它们与人类对应物具有高度同源性，并具有所有 KLK 定义特征。对于（CANFA）KLK9，除了经典形式的基因外，还鉴定了另外三种带有外显子 3 跳过和/或内含子 I 保留的选择性剪接变体。KLK9 的经典形式和变体 1 以及 KLK10 在所有检查的组织中广泛表达。KLK9 变体 2 和 3 的阳性率较低。然而，这些转录物在肿瘤和正常组织之间没有表现出任何优先或差异表达。有趣的是，（CANFA）KLK9 和（CANFA）KLK10 在几乎所有组织样本中同时表达；这表明这些丝氨酸蛋白酶可能参与共同的蛋白水解级联反应。总体而言，这是第一项实验表征犬科 KLK9 和 KLK10 并证明其在正常和恶性组织中表达的研究。
