The role of miR-17-92 in the miRegulatory landscape of Ewing sarcoma.
The role of miR-17-92 in the miRegulatory landscape of Ewing sarcoma.
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DOI：
10.18632/oncotarget.14091
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发表时间：
2017-02-14
期刊：
影响因子：
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通讯作者：
Kovar H
中科院分区：
文献类型：
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作者：
Schwentner R;Herrero-Martin D;Kauer MO;Mutz CN;Katschnig AM;Sienski G;Alonso J;Aryee DN;Kovar H
MicroRNA 用于微调基因表达，并在组织特异性基因网络中发挥重要的调节作用。组织中 miRNA 靶基因的识别和验证仍然是一个重大问题，因为 mRNA 3'UTR 中种子序列的存在及其对 miRNA 异位表达的表达调节不能可靠地预测生理条件下的调节。嵌合癌蛋白 EWS-FLI1 是尤文肉瘤的致病驱动力。 MiR-17-92 是最有效的致癌 miRNA 之一，最近据报道是 EWS-FLI1 激活的顶级 miRNA 之一。结合使用 PAR-CLIP（光活化核糖核苷增强交联和免疫沉淀）进行的 AGO2 下拉实验和异位海绵表达消耗 miRNA 时的 RNAseq，我们的目的是鉴定尤文肉瘤中 miR-17-92 的靶标组。交叉这两个数据集，我们发现 miR-17-92 簇成员的 PAR-CLIP 命中富集在响应 mir-17-92 特异性海绵表达而上调的基因 3'UTR 中。引人注目的是，大约四分之一的这些基因注释到 TGFB/BMP 通路，其中大多数映射到 SMAD 信号传导的下游。通过测试 SMAD 磷酸化，我们发现了安静但可激活的 TGFB 信号传导和 BMP 通路的细胞自主活性，从而导致干性调节转录阻遏物 ID1 和 ID3 的激活。总而言之，我们的研究结果揭示了尤文肉瘤复杂的 miRegulatory 景观，指出 miR-17-92 是与 TGFB/BMP 通路相关的关键节点。
MicroRNAs serve to fine-tune gene expression and play an important regulatory role in tissue specific gene networks. The identification and validation of miRNA target genes in a tissue still poses a significant problem since the presence of a seed sequence in the 3′UTR of an mRNA and its expression modulation upon ectopic expression of the miRNA do not reliably predict regulation under physiological conditions. The chimeric oncoprotein EWS-FLI1 is the driving pathogenic force in Ewing sarcoma. MiR-17-92, one of the most potent oncogenic miRNAs, was recently reported to be among the top EWS-FLI1 activated miRNAs. Using a combination of AGO2 pull-down experiments by PAR-CLIP (Photoactivatable-Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation) and of RNAseq upon miRNA depletion by ectopic sponge expression, we aimed to identify the targetome of miR-17-92 in Ewing sarcoma. Intersecting both datasets we found an enrichment of PAR-CLIP hits for members of the miR-17-92 cluster in the 3′UTRs of genes up-regulated in response to mir-17-92 specific sponge expression. Strikingly, approximately a quarter of these genes annotate to the TGFB/BMP pathway, the majority mapping downstream of SMAD signaling. Testing for SMAD phosphorylation, we identify quiet but activatable TGFB signaling and cell autonomous activity of the BMP pathway resulting in the activation of the stemness regulatory transcriptional repressors ID1 and ID3. Taken together, our findings shed light on the complex miRegulatory landscape of Ewing Sarcoma pointing miR-17-92 as a key node connected to TGFB/BMP pathway.