Gene expression profiling analysis of CRTC1-MAML2 fusion oncogene-induced transcriptional program in human mucoepidermoid carcinoma cells.
Gene expression profiling analysis of CRTC1-MAML2 fusion oncogene-induced transcriptional program in human mucoepidermoid carcinoma cells.
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DOI：
10.1186/s12885-015-1827-3
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发表时间：
2015-10-26
期刊：
影响因子：
3.8
通讯作者：
Wu L
中科院分区：
文献类型：
--
作者：
Chen J;Li JL;Chen Z;Griffin JD;Wu L
粘液表皮样癌（MEC）起源于多个器官，是涎腺恶性肿瘤中最常见的类型。目前，患有不可切除和转移性MEC的患者的长期临床结果较差，并且没有靶向治疗。大多数MEC肿瘤含有t（11;19）染色体易位，其融合两个基因CRTC 1和MAML 2以产生嵌合蛋白CRTC 1-MAML 2。CRTC 1-MAML 2在体外表现出转化活性，并且是人类MEC细胞生长和生存所必需的，部分原因是其能够组成性激活CREB介导的转录。因此，CRTC 1-MAML 2被认为是MEC的主要病因学分子事件和治疗靶点。然而，CRTC 1-MAML 2致癌作用在MEC的分子机制尚未得到系统的分析。阐明CRTC 1-MAML 2调控的转录程序及其潜在机制将为MEC发病机制提供重要的见解，这对于靶向治疗的发展至关重要。通过shRNA介导的基因敲低，在内源性CRTC 1-MAML 2融合物或其相互作用伴侣CREB耗尽的情况下，对人MEC细胞进行转录谱分析。通过实时RT-PCR测定验证靶基因的子集。通过途径分析鉴定MEC中CRTC 1-MAML 2干扰的分子途径。最后，比较分析CRTC 1-MAML 2调节和CREB调节的转录谱，以评估CREB在介导CRTC 1-MAML 2诱导的转录中的贡献。CRTC 1-MAML 2基因敲低后，在人MEC细胞中共鉴定出808个差异表达基因，并通过实时RT-PCR证实了已知和新融合靶基因的子集。通路分析显示，CRTC 1-MAML 2调节基因与细胞生长、增殖、存活、迁移和代谢的重要网络功能相关。CRTC 1-MAML 2调节和CREB调节的转录谱的比较揭示了分别由CRTC 1-MAML 2和CREB调节的共同和不同的基因。这项研究确定了一个特定的CRTC 1-MAML 2诱导的人类MEC细胞的转录程序，并证明CRTC 1-MAML 2调节CREB依赖和独立的方式基因表达。我们的数据提供了CRTC 1-MAML 2致癌功能的分子基础，并为进一步研究CRTC 1-MAML 2诱导的信号在MEC启动和维持中的功能奠定了基础。本文的在线版本（doi：10.1186/s12885-015-1827-3）包含补充材料，可供授权用户使用。
Mucoepidermoid carcinoma (MEC) arises from multiple organs and accounts for the most common types of salivary gland malignancies. Currently, patients with unresectable and metastatic MEC have poor long-term clinical outcomes and no targeted therapies are available. The majority of MEC tumors contain a t(11;19) chromosomal translocation that fuses two genes, CRTC1 and MAML2, to generate the chimeric protein CRTC1-MAML2. CRTC1-MAML2 displays transforming activity in vitro and is required for human MEC cell growth and survival, partially due to its ability to constitutively activate CREB-mediated transcription. Consequently, CRTC1-MAML2 is implicated as a major etiologic molecular event and a therapeutic target for MEC. However, the molecular mechanisms underlying CRTC1-MAML2 oncogenic action in MEC have not yet been systematically analyzed. Elucidation of the CRTC1-MAML2-regulated transcriptional program and its underlying mechanisms will provide important insights into MEC pathogenesis that are essential for the development of targeted therapeutics. Transcriptional profiling was performed on human MEC cells with the depletion of endogenous CRTC1-MAML2 fusion or its interacting partner CREB via shRNA-mediated gene knockdown. A subset of target genes was validated via real-time RT-PCR assays. CRTC1-MAML2-perturbed molecular pathways in MEC were identified through pathway analyses. Finally, comparative analysis of CRTC1-MAML2-regulated and CREB-regulated transcriptional profiles was carried out to assess the contribution of CREB in mediating CRTC1-MAML2-induced transcription. A total of 808 differentially expressed genes were identified in human MEC cells after CRTC1-MAML2 knockdown and a subset of known and novel fusion target genes was confirmed by real-time RT-PCR. Pathway Analysis revealed that CRTC1-MAML2-regulated genes were associated with network functions that are important for cell growth, proliferation, survival, migration, and metabolism. Comparison of CRTC1-MAML2-regulated and CREB-regulated transcriptional profiles revealed common and distinct genes regulated by CRTC1-MAML2 and CREB, respectively. This study identified a specific CRTC1-MAML2-induced transcriptional program in human MEC cells and demonstrated that CRTC1-MAML2 regulates gene expression in CREB-dependent and independent manners. Our data provide the molecular basis underlying CRTC1-MAML2 oncogenic functions and lay a foundation for further functional investigation of CRTC1-MAML2-induced signaling in MEC initiation and maintenance. The online version of this article (doi:10.1186/s12885-015-1827-3) contains supplementary material, which is available to authorized users.