Increased Expression of miR-23a Mediates a Loss of Expression in the RAF Kinase Inhibitor Protein RKIP.
Increased Expression of miR-23a Mediates a Loss of Expression in the RAF Kinase Inhibitor Protein RKIP.
复制标题
DOI：
10.1158/0008-5472.can-15-3049
复制
发表时间：
2016-06-15
期刊：
影响因子：
11.2
通讯作者：
Zebisch A
中科院分区：
文献类型：
--
作者：
Hatzl S;Geiger O;Kuepper MK;Caraffini V;Seime T;Furlan T;Nussbaumer E;Wieser R;Pichler M;Scheideler M;Nowek K;Jongen-Lavrencic M;Quehenberger F;Wölfler A;Troppmair J;Sill H;Zebisch A
RAF 激酶抑制剂蛋白 (RKIP) 是细胞内信号传导的精液调节剂，具有抗转移和抗肿瘤发生的特性。 RKIP 表达降低在多种人类恶性肿瘤中都有报道，包括急性髓性白血病 (AML)。由于导致 AML 中 RKIP 丢失的机制仍不清楚，我们旨在分析 miRNA 在本研究中的潜在参与。超过 400 份 AML 患者样本的 miRNA 微阵列和 qPCR 数据揭示了 RKIP 表达减少与 miR-23a（miR-23a/27a/24-2 簇成员）表达增加之间的相关性。在功能实验中，miR-23a的过度表达降低了RKIP mRNA和蛋白质的表达，而miR-23a的抑制则产生相反的效果。通过使用带有或不带有假定的 miR-23a 结合位点突变或缺失的 RKIP 3'-非翻译区荧光素酶报告基因构建体，我们可以证明 miR-23a 的 RKIP 调节是通过直接结合到该区域来介导的。重要的是，miR-23a 过表达诱导造血细胞增殖显着增加。同时转染缺乏 miR-23a 结合位点的 RKIP 表达构建体逆转了这种表型，表明这种效应确实是通过下调 RKIP 介导的。最后，通过从癌症基因组图谱中检索数据库来分析 4,300 多个主要患者样本，我们可以强调 miR-23a/RKIP 轴在广泛的人类癌症实体中的重要性。总之，我们已经确定 miR-23a 是 AML 中 RKIP 表达的负调节因子，并提供的数据表明我们观察这一肿瘤实体之外的重要性。
RAF kinase inhibitor protein (RKIP) is a seminal regulator of intracellular signaling and exhibits both antimetastatic and antitumorigenic properties. Decreased expression of RKIP has been described in several human malignancies, including acute myelogenous leukemia (AML). As the mechanisms leading to RKIP loss in AML are still unclear, we aimed to analyze the potential involvement of miRNAs within this study. miRNA microarray and qPCR data of more than 400 AML patient specimens revealed correlation between decreased expression of RKIP and increased expression of miR-23a, a member of the miR-23a/27a/24-2 cluster. In functional experiments, overexpression of miR-23a decreased RKIP mRNA and protein expression, whereas miR-23a inhibition caused the opposite effect. By using an RKIP 3′-untranslated region luciferase reporter construct with and without mutation or deletion of the putative miR-23a–binding site, we could show that RKIP modulation by miR-23a is mediated via direct binding to this region. Importantly, miR-23a overexpression induced a significant increase of proliferation in hematopoietic cells. Simultaneous transfection of an RKIP expression construct lacking the miR-23a–binding sites reversed this phenotype, indicating that this effect is truly mediated via downregulation of RKIP. Finally, by analyzing more than 4,300 primary patient specimens via database retrieval from The Cancer Genome Atlas, we could highlight the importance of the miR-23a/RKIP axis in a broad range of human cancer entities. In conclusion, we have identified miR-23a as a negative regulator of RKIP expression in AML and have provided data that suggest the importance of our observation beyond this tumor entity.