Both YAP1-MAML2 and constitutively active YAP1 drive the formation of tumors that resemble NF2 mutant meningiomas in mice [human]
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ABSTRACT: We analyzed the expression profiles of human and mouse meningiomas (driven by NF2 loss, YAP1-MAML2, TRAF7/KLF4/SMO1/AKT1, or constitutively active non-fusion YAP1). We found that YAP1-MAML2 meningiomas resemble NF2mutant tumors and constitutively exert de-regulated YAP1 activity that is dependent on the interaction with TEADs.
Project description:We analyzed the expression profiles of human and mouse meningiomas (driven by NF2 loss, YAP1-MAML2, TRAF7/KLF4/SMO1/AKT1, or constitutively active non-fusion YAP1). We found that YAP1-MAML2 meningiomas resemble NF2mutant tumors and constitutively exert de-regulated YAP1 activity that is dependent on the interaction with TEADs.
Project description:YAP1 is a transcriptional coactivator regulated by the Hippo signaling pathway, including NF2. Meningiomas are the most common primary brain tumors; a large percentage exhibit heterozygous loss of chromosome 22 (harboring the NF2 gene) and functional inactivation of the remaining NF2 copy, implicating oncogenic YAP activity in these tumors. Recently, fusions between YAP1 and MAML2 have been identified in a subset of pediatric NF2 wild-type meningiomas. Here, we show that human YAP1-MAML2-positive meningiomas resemble NF2 mutant meningiomas by global and YAP-related gene expression signatures. We then show that expression of YAP1-MAML2 in mice induces tumors that resemble human YAP1 fusion-positive and NF2 mutant meningiomas by gene expression. We demonstrate that YAP1-MAML2 primarily functions by exerting TEAD-dependent YAP activity that is resistant to Hippo signaling. Treatment with YAP-TEAD inhibitors is sufficient to inhibit the viability of YAP1-MAML2-driven mouse tumors ex vivo. Finally, we show that expression of constitutively active YAP1 (S127/397A-YAP1) is sufficient to induce similar tumors, suggesting that the YAP component of the gene fusion is the critical driver of these tumors. In summary, our results implicate YAP1-MAML2 as a causal oncogenic driver and highlight TEAD-dependent YAP activity as an oncogenic driver in YAP1-MAML2 fusion meningioma as well as NF2 mutant meningioma in general.
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.
Project description:We report genomic analysis of 300 meningiomas, the most common primary brain tumors, leading to the discovery of mutations in TRAF7, a proapoptotic E3 ubiquitin ligase, in nearly one-fourth of all meningiomas. Mutations in TRAF7 commonly occurred with a recurrent mutation (K409Q) in KLF4, a transcription factor known for its role in inducing pluripotency, or with AKT1(E17K), a mutation known to activate the PI3K pathway. SMO mutations, which activate Hedgehog signaling, were identified in ~5% of non-NF2 mutant meningiomas. These non-NF2 meningiomas were clinically distinctive-nearly always benign, with chromosomal stability, and originating from the medial skull base. In contrast, meningiomas with mutant NF2 and/or chromosome 22 loss were more likely to be atypical, showing genomic instability, and localizing to the cerebral and cerebellar hemispheres. Collectively, these findings identify distinct meningioma subtypes, suggesting avenues for targeted therapeutics. Analysis of meningioma gene expression data for each mutation subtype. Includes gene expression data from 75 unique meningiomas and 39 replicates.
Project description:Meningiomas are the most common primary brain tumors in adults. Although generally benign, a subset is of higher grade, recurs even after multiple surgeries, and frequently fatal. Around half of meningiomas harbor inactivating mutations in NF2. While low-grade NF2 mutant meningiomas harbor few additional mutations in addition to NF2 inactivation, high-grade NF2 mutant tumors frequently harbor a highly aberrant genome. We and others have previously shown that NF2 inactivation leads to YAP1 activation and that YAP1 acts as an oncogene in NF2 mutant meningiomas. Here, we show that high-grade NF2 mutant meningiomas downregulate YAP1 signaling, in part through upregulating the expression of the YAP1 competitor VGLL4 and the YAP1 upstream regulators FAT3/4. Overexpression of VGLL4 resulted in the downregulation of YAP activity and the growth inhibition of low-grade NF2 mutant meningioma cells. Our results have important implications for the efficacy of therapies targeting oncogenic YAP1 in high-grade NF2 mutant meningiomas.
Project description:We report genomic analysis of 300 meningiomas, the most common primary brain tumors, leading to the discovery of mutations in TRAF7, a proapoptotic E3 ubiquitin ligase, in nearly one-fourth of all meningiomas. Mutations in TRAF7 commonly occurred with a recurrent mutation (K409Q) in KLF4, a transcription factor known for its role in inducing pluripotency, or with AKT1(E17K), a mutation known to activate the PI3K pathway. SMO mutations, which activate Hedgehog signaling, were identified in ~5% of non-NF2 mutant meningiomas. These non-NF2 meningiomas were clinically distinctive-nearly always benign, with chromosomal stability, and originating from the medial skull base. In contrast, meningiomas with mutant NF2 and/or chromosome 22 loss were more likely to be atypical, showing genomic instability, and localizing to the cerebral and cerebellar hemispheres. Collectively, these findings identify distinct meningioma subtypes, suggesting avenues for targeted therapeutics.
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.