CRTC1-MAML2 fusion oncogene-induced transcriptional program is regulated by CREB-dependent and -independent mechanisms
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE59795 | GEO | 2014/07/25
SECONDARY ACCESSION(S): PRJNA256213
REPOSITORIES: GEO
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Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2014-07-25 | E-GEOD-59795 | biostudies-arrayexpress
Project description:CRTC1-MAML2 fusion oncogene-induced transcriptional program is regulated by CREB-dependent and -independent mechanisms
| PRJNA256213 | ENA
Project description:Mucoepidermoid carcinomas (MEC) is the most common salivary gland malignancy. To date, advanced and nonresectable MEC have poor prognosis and no effective treatment. The CRTC1-MAML2 fusion oncogene, which is associated with more than 50% of MEC, consists of the N-terminal CREB-binding domain of the CREB transcriptional co-activator CRTC1 and the C-terminal transcriptional activation domain of the Notch transcriptional co-activator MAML2. CRTC1-MAML2 fusion was found to interact with CREB and constitutively activate their transcriptional targets. To investigate the genes and pathways regulated by CRTC1-MAML2 fusion oncogene, gene expression profiling analysis were performed in human fusion-positive MEC cells before and after knockdown of both CRTC1-MAML2 and MAML2 as well as in human fusion-negative salivary gland cancer cells before and after MAML2 knockdown only. This study revealed specific transcriptional program induced by the CRTC1-MAML2 fusion oncogene, which potentially mediates CRC1-MAML2 functions in MEC initiation and maintenance. The information will be useful for developing new approaches to block CRTC1-MAML2 fusion-expressing MEC. The fusion-positive H3118 MEC cells were used in this study. The fusion knockdown was performed with two biological replicates for each group. Since we are unable to obtain any shRNA that causes specific knockdown of CRTC1-MAML2, we utilized pSuperRetro-based retroviruses that express shRNA targeting the MAML2 TAD as well as GFP for fusion knock down, and the retroviruses express shRNA targeting luciferase gene (shLuc) and GFP for the control. Cells were infected with retroviruses and cultured for 48 hours. FACS sorting was performed to obtain GFP-positive cells and thus enrich shRNA-expressing cells. RNA was subsequently harvested for microarray analysis. The shMAML2 retroviruses caused the knockdown of MAML2 and CRTC1-MAML2 fusion in fusion-positive H3118 cells.
2014-04-21 | E-GEOD-46580 | biostudies-arrayexpress
Project description:BackgroundMucoepidermoid 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.MethodsTranscriptional 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.ResultsA 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.ConclusionThis 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.
| S-EPMC4624166 | biostudies-literature
Project description:Mucoepidermoid carcinomas (MEC) is the most common salivary gland malignancy. To date, advanced and nonresectable MEC have poor prognosis and no effective treatment. The CRTC1-MAML2 fusion oncogene, which is associated with more than 50% of MEC, consists of the N-terminal CREB-binding domain of the CREB transcriptional co-activator CRTC1 and the C-terminal transcriptional activation domain of the Notch transcriptional co-activator MAML2. CRTC1-MAML2 fusion was found to interact with CREB and constitutively activate their transcriptional targets. To investigate the genes and pathways regulated by CRTC1-MAML2 fusion oncogene, gene expression profiling analysis were performed in human fusion-positive MEC cells before and after knockdown of both CRTC1-MAML2 and MAML2 as well as in human fusion-negative salivary gland cancer cells before and after MAML2 knockdown only. This study revealed specific transcriptional program induced by the CRTC1-MAML2 fusion oncogene, which potentially mediates CRC1-MAML2 functions in MEC initiation and maintenance. The information will be useful for developing new approaches to block CRTC1-MAML2 fusion-expressing MEC.
2014-04-21 | GSE46580 | GEO
Project description:No effective systemic treatment is available for patients with unresectable, recurrent, or metastatic mucoepidermoid carcinoma (MEC), the most common salivary gland malignancy. MEC is frequently associated with a t(11;19)(q14-21;p12-13) translocation that creates a CRTC1-MAML2 fusion gene. The CRTC1-MAML2 fusion exhibited transforming activity in vitro; however, whether it serves as an oncogenic driver for MEC establishment and maintenance in vivo remains unknown. Here, we show that doxycycline-induced CRTC1-MAML2 knockdown blocked the growth of established MEC xenografts, validating CRTC1-MAML2 as a therapeutic target. We further generated a conditional transgenic mouse model and observed that Cre-induced CRTC1-MAML2 expression caused 100% penetrant formation of salivary gland tumors resembling histological and molecular characteristics of human MEC. Molecular analysis of MEC tumors revealed altered p16-CDK4/6-RB pathway activity as a potential cooperating event in promoting CRTC1-MAML2-induced tumorigenesis. Cotargeting of aberrant p16-CDK4/6-RB signaling and CRTC1-MAML2 fusion-activated AREG/EGFR signaling with the respective CDK4/6 inhibitor Palbociclib and EGFR inhibitor Erlotinib produced enhanced antitumor responses in vitro and in vivo. Collectively, this study provides direct evidence for CRTC1-MAML2 as a key driver for MEC development and maintenance and identifies a potentially novel combination therapy with FDA-approved EGFR and CDK4/6 inhibitors as a potential viable strategy for patients with MEC.
| S-EPMC8119194 | biostudies-literature
Project description:ObjectiveMucoepidermoid carcinoma (MEC) is the most common malignant tumor of the salivary glands. Tumor stage and grade have historically been important predictors of survival. An oncogenic CRTC1- or CRTC3-MAML2 gene fusion has been identified in a number of MECs. Historically, these gene fusions have been associated with lower grade tumors and better survival. However, reported gene fusion rates and prognosis varies widely across studies, and have not controlled for tumor grade. We sought to identify gene fusion rates and outcomes in our cohort of MEC patients.Materials and methodsAn IRB-approved retrospective cohort of patients with MEC was identified at the University of Michigan. Clinical, histologic, and outcome data was collected from medical records. RNA was isolated from formalin fixed paraffin-embedded tumor sections, and qRT-PCR was performed to identify CRTC1/3-MAML2 gene fusions. Sanger sequencing of qRT-PCR products was used to confirm gene fusions.ResultsOverall, 90 patient MEC tumors were collected (58 low-grade, 25 intermediate-grade, and 7 high-grade). Gene fusions were identified in 59% (53/90) of tumors. On univariate and bivariate analysis, fusion status did not significantly associate with grade or survival.ConclusionWe have identified a high rate of CRTC1/3-MAML2 gene fusions in a large cohort of MEC. We do not identify any correlation between fusion status with tumor grade or survival. These findings suggest further characterization of MECs is needed before considering the CRTC1/3-MAML2 gene fusion as a prognostic biomarker. Additional genetic drivers may account for survival and grade in MECs.
| S-EPMC5433350 | biostudies-literature
Project description:Chimeric oncoproteins created by chromosomal translocations are among the most common genetic mutations associated with tumorigenesis. Malignant mucoepidermoid salivary gland tumors, as well as a growing number of solid epithelial-derived tumors, can arise from a recurrent t (11, 19)(q21;p13.1) translocation that generates an unusual chimeric cAMP response element binding protein (CREB)-regulated transcriptional coactivator 1 (CRTC1)/mastermind-like 2 (MAML2) (C1/M2) oncoprotein comprised of two transcriptional coactivators, the CRTC1 and the NOTCH/RBPJ coactivator MAML2. Accordingly, the C1/M2 oncoprotein induces aberrant expression of CREB and NOTCH target genes. Surprisingly, here we report a gain-of-function activity of the C1/M2 oncoprotein that directs its interactions with myelocytomatosis oncogene (MYC) proteins and the activation of MYC transcription targets, including those involved in cell growth and metabolism, survival, and tumorigenesis. These results were validated in human mucoepidermoid tumor cells that harbor the t (11, 19)(q21;p13.1) translocation and express the C1/M2 oncoprotein. Notably, the C1/M2-MYC interaction is necessary for C1/M2-driven cell transformation, and the C1/M2 transcriptional signature predicts other human malignancies having combined involvement of MYC and CREB. These findings suggest that such gain-of-function properties may also be manifest in other oncoprotein fusions found in human cancer and that agents targeting the C1/M2-MYC interface represent an attractive strategy for the development of effective and safe anticancer therapeutics in tumors harboring the t (11, 19) translocation.
| S-EPMC4136562 | biostudies-literature
Project description:Mucoepidermoid carcinoma (MEC) is the most common malignant tumor of the major and minor salivary glands. Surgical resection is the only curative treatment and there is no effective post-operative therapy for MEC. The present study reports an Institutional Review Board-approved case of a 45-year-old Japanese female diagnosed with low-grade MEC in the hard palate. Radical resection, supraomohyoid neck dissection and antero-lateral thigh flap reconstruction was performed. A MEC cell line was then established from the resected tumor tissue. Short tandem repeat profiling confirmed the origin and authenticity of the cell line, that harbors a CRTC1-MAML2 translocation, which is frequently observed in MEC. Amphiregulin (AREG), identified as one of the targets of the CRTC1-MAML2 fusion gene, was expressed in the cell line. The AREG receptor, epidermal growth factor receptor (EGFR) was also highly phosphorylated. The results predicted that AREG-EGFR signaling, which is required for tumor growth and survival, might be activated in the cell line in a cell-autonomous manner. As AREG expression is associated with EGFR-targeted drug resistance, this cell line might assist with the identification of novel strategies for MEC treatment.
| S-EPMC8848773 | biostudies-literature
Project description:Mucoepidermoid carcinoma (MEC) arises in many glandular tissues and contributes to the most common malignant salivary gland cancers. MEC is specifically associated with a unique t(11;19) translocation and the resulting CRTC1-MAML2 fusion is a major oncogenic driver for MEC initiation and maintenance. However, the molecular basis underlying the CRTC1-MAML2 oncogenic functions remains elusive. Through gene expression profiling analysis, we observed that LINC00473, a long non-coding RNA (lncRNA), was the top down-regulated target in CRTC1-MAML2-depleted human MEC cells. LncRNAs belong to a new class of non-coding RNAs with emerging roles in tumorigenesis and progression, but remain poorly characterized. In this study, we investigated the role of LINC00473 in mediating CRTC1-MAML2 oncogenic activity in human MEC. We found that LINC00473 transcription was significantly induced in human CRTC1-MAML2-positive MEC cell lines and primary MEC tumors, and was tightly correlated with the CRTC1-MAML2 RNA level. LINC00473 induction was dependent on the ability of CRTC1-MAML2 to activate CREB-mediated transcription. Depletion of LINC00473 significantly reduced the proliferation and survival of human MEC cells in vitro and blocked the in vivo tumor growth in a human MEC xenograft model. RNA in situ hybridization analysis demonstrated a predominantly nuclear localization pattern for LINC00473 in human MEC cells. Furthermore, gene expression profiling revealed that LINC00473 depletion resulted in differential expression of genes important in cancer cell growth and survival. LINC00473 likely regulates gene expression in part through its ability to bind to a cAMP signaling pathway component NONO, enhancing the ability of CRTC1-MAML2 to activate CREB-mediated transcription. Our overall results demonstrate that LINC00473 is a downstream target and an important mediator of the CRTC1-MAML2 oncoprotein. Therefore, LINC00473 acts as a promising biomarker and therapeutic target for human CRTC1-MAML2-positive MECs.
| S-EPMC5889358 | biostudies-literature