ABSTRACT: Global Profiling in Vestibular Schwannomas Shows Critical Deregulation of MicroRNAs and Upregulation in those included in Chromosomal Region 14q32
Project description:Background: Vestibular Schwannomas are benign tumors that arise from Schwann cells in the VIII cranial pair and usually present NF2 gene mutations and/or loss of heterozygosity on chromosome 22q. Deregulation has also been found in several genes, such as ERBB2 and NRG1. MicroRNAs are non-coding RNAs approximately 21 to 23 nucleotides in length that regulate mRNAs, usually by degradation at the post-transcriptional level. Methods: We used microarray technology to test the deregulation of miRNAs and other non-coding RNAs present in GeneChip miRNA 1.0 (Affymetrix) over 16 vestibular Schwannomas and 3 control-nerves, validating 10 of them by qRT-PCR. Findings: Our results showed the deregulation of 174 miRNAs, including miR-10b, miR-206, miR-183 and miR-204, and the upregulation of miR-431, miR-221, miR-21 and miR-720, among others. The results also showed an aberrant expression of other non-coding RNAs. We also found a general upregulation of the miRNA cluster located at chromosome 14q32. Conclusion: Our results suggest that several miRNAs are involved in tumor formation and/or maintenance and that global upregulation of the 14q32 chromosomal site may represent a therapeutic target for this neoplasm. 16 Vestibular Schwannomas and 3 control-nerves were analysed
Project description:Background: Vestibular Schwannomas are benign tumors that arise from Schwann cells in the VIII cranial pair and usually present NF2 gene mutations and/or loss of heterozygosity on chromosome 22q. Deregulation has also been found in several genes, such as ERBB2 and NRG1. MicroRNAs are non-coding RNAs approximately 21 to 23 nucleotides in length that regulate mRNAs, usually by degradation at the post-transcriptional level. Methods: We used microarray technology to test the deregulation of miRNAs and other non-coding RNAs present in GeneChip miRNA 1.0 (Affymetrix) over 16 vestibular Schwannomas and 3 control-nerves, validating 10 of them by qRT-PCR. Findings: Our results showed the deregulation of 174 miRNAs, including miR-10b, miR-206, miR-183 and miR-204, and the upregulation of miR-431, miR-221, miR-21 and miR-720, among others. The results also showed an aberrant expression of other non-coding RNAs. We also found a general upregulation of the miRNA cluster located at chromosome 14q32. Conclusion: Our results suggest that several miRNAs are involved in tumor formation and/or maintenance and that global upregulation of the 14q32 chromosomal site may represent a therapeutic target for this neoplasm.
Project description:Vestibular schwannomas are intracranial tumors that affects unilateral and sporadically or bilateral when is associated to Neurofibromatosis type 2 syndrome. The hallmark of the disease is the biallelic inactivation by NF2 gene mutation or LOH of chromosome 22q, where this gene harbors. In this work, we used Infinium HumanMethylation 450K BeadChip microarrays in a series of 36 vestibular schwannomas, 4 non-vestibular schwannomas and 5 healthy nerves. Our results shows a trend to hypomethylation in schwannomas. Furthermore, HOX genes, located at 4 clusters in the genome, displayed hypomethylation in numerous CpG sites in vestibular but not in non-vestibular schwannomas. Additionally, several microRNA and protein-coding genes were found hypomethylated at promoter regions and confirmed by expression analysis; including miRNA-199a1, miRNA-21, MET and PMEPA1. We also detected methylation patterns that might be involved in alternative transcripts of several genes such as NRXN1 or MBP; that would increase the complexity of methylation-expression. Overall, our results shows specific epigenetic signatures in several coding genes and microRNA that could be used in the finding of potential therapeutic targets.
Project description:Vestibular schwannomas are intracranial tumors that affects unilateral and sporadically or bilateral when is associated to Neurofibromatosis type 2 syndrome. The hallmark of the disease is the biallelic inactivation by NF2 gene mutation or LOH of chromosome 22q, where this gene harbors. In this work, we used Infinium HumanMethylation 450K BeadChip microarrays in a series of 36 vestibular schwannomas, 4 non-vestibular schwannomas and 5 healthy nerves. Our results shows a trend to hypomethylation in schwannomas. Furthermore, HOX genes, located at 4 clusters in the genome, displayed hypomethylation in numerous CpG sites in vestibular but not in non-vestibular schwannomas. Additionally, several microRNA and protein-coding genes were found hypomethylated at promoter regions and confirmed by expression analysis; including miRNA-199a1, miRNA-21, MET and PMEPA1. We also detected methylation patterns that might be involved in alternative transcripts of several genes such as NRXN1 or MBP; that would increase the complexity of methylation-expression. Overall, our results shows specific epigenetic signatures in several coding genes and microRNA that could be used in the finding of potential therapeutic targets.
Project description:Tumor miRNA expression is related to the growth rate of sporadic vestibular schwannomas. Rapid tumor growth is associated with deregulation of several miRNAs, including up-regulation of miR-29abc, miR-19, miR-340-5p, miR-21 and miR-221 and down-regulation of miR-744 and let-7b. Gene ontologies affected by the deregulated miRNAs included neuron development and differentiation, gene silencing and negative regulation of various biological processes, including cellular and intracellular signalling and metabolism. We used microarray to determine the miRNA expresison in vestibular schwannoma their relation to the growth rate.
Project description:Vestibular Schwannomas are benign neoplasms that arise from the vestibular nerve. The hallmark of these tumors is the biallelic inactivation of NF2. Transcriptomic alterations, such as the Nrg1/ErbB2 pathway, have been described in Schwannomas. Here, we have performed a whole transcriptomic analysis in 31 vestibular Schwannomas and 9 control nerves in the Affymetrix Gene 1.0ST platform, validated by quantitative Real-Time PCR using TaqMan Low Density Arrays. We performed a mutational analysis of NF2 by PCR/dHPLC and MLPA as well as a microsatellite marker analysis of the loss of heterozygosity of chromosome 22q. The microarray analysis showed that 1516 genes were deregulated, and 48 of the genes were validated by qRT-PCR. At least two genetic hits (allelic loss and/or gene mutation) in NF2 were found in 16 tumors, seven cases showed one hit and eight tumors showed no NF2 alteration. As conclusion, MET and associated genes such as ITGA4/B6, PLEXNB3/SEMA5 and CAV1 showed a clear deregulation in vestibular Schwannomas. In addition, androgen receptor (AR) downregulation may denote a hormonal effect or cause in this tumor. Furthermore, the osteopontin gene (SPP1), which is involved in Merlin protein degradation, was upregulated, which suggests that this mechanism may also exert a pivotal role in Schwannoma Merlin depletion. Finally, no major differences were found between tumors of different sizes, histological types or NF2 status, which suggests that at the mRNA level all Schwannomas, regardless of molecular and clinical characteristics, may share common features that can be used in the fight against them. In order to find target to fight against vestibular schwannoma, we performed an analysis of gene expression by microarrays.
Project description:Vestibular Schwannomas are benign neoplasms that arise from the vestibular nerve. The hallmark of these tumors is the biallelic inactivation of NF2. Transcriptomic alterations, such as the Nrg1/ErbB2 pathway, have been described in Schwannomas. Here, we have performed a whole transcriptomic analysis in 31 vestibular Schwannomas and 9 control nerves in the Affymetrix Gene 1.0ST platform, validated by quantitative Real-Time PCR using TaqMan Low Density Arrays. We performed a mutational analysis of NF2 by PCR/dHPLC and MLPA as well as a microsatellite marker analysis of the loss of heterozygosity of chromosome 22q. The microarray analysis showed that 1516 genes were deregulated, and 48 of the genes were validated by qRT-PCR. At least two genetic hits (allelic loss and/or gene mutation) in NF2 were found in 16 tumors, seven cases showed one hit and eight tumors showed no NF2 alteration. As conclusion, MET and associated genes such as ITGA4/B6, PLEXNB3/SEMA5 and CAV1 showed a clear deregulation in vestibular Schwannomas. In addition, androgen receptor (AR) downregulation may denote a hormonal effect or cause in this tumor. Furthermore, the osteopontin gene (SPP1), which is involved in Merlin protein degradation, was upregulated, which suggests that this mechanism may also exert a pivotal role in Schwannoma Merlin depletion. Finally, no major differences were found between tumors of different sizes, histological types or NF2 status, which suggests that at the mRNA level all Schwannomas, regardless of molecular and clinical characteristics, may share common features that can be used in the fight against them.
Project description:Background: Neurofibromatosis type 2 (NF2) is an autosomal dominant genetic disease characterized by the development of multiple Schwannomas, usually occurring on both VIIIth (vestibular) cranial nerves. Bromodomain and extra-terminal domain (BET) proteins regulate gene transcription and their activity is required in a variety of cancers including malignant peripheral nerve sheath tumors (MPNST). The use of BET inhibitors as a therapeutic option to treat NF2 schwannomas has not been explored and is the focus of this study. Methods: A panel of normal and NF2-null Schwann cell and schwannoma cell lines were used to characterize the impact of the BET inhibitor JQ1 in vitro and in vivo. The mechanism of action was explored by chromatin immunoprecipitation (ChIP) of the BET BRD4, phospho-kinase arrays and immunohistochemistry of BRD4 in human vestibular schwannomas. Results: JQ1 inhibited the proliferation of NF2-null schwannoma and Schwann cell lines in vitro and in vivo. Further, loss of NF2 by CRISPR deletion or siRNA knockdown increased the sensitivity of cells to JQ1. Knock-down experiments identified BRD4 as the BET family member mediating the majority of JQ1 effects on cell proliferation. Immunohistochemistry demonstrated elevated levels of BRD4 protein in human vestibular schwannomas. BRD4 ChIP experiments identified the small G-protein Rac1 and PI3K signaling pathways as sensitive to JQ1. Conclusions: NF2 deficient Schwann cell and schwannoma cells are sensitive to BET inhibition, primarily mediated by BRD4, which is overexpressed in human vestibular schwannomas. BRD4 regulates Rac/Ras and PI3K signaling pathways and inhibition of these pathways by JQ1 impedes NF2 Schwannoma growth. These findings implicate BET inhibition as a therapeutic option for NF2-deficient schwannomas.
Project description:MicroRNAs (miRNAs) negatively regulate protein-coding genes at the post-transcriptional level and are critical in tumorigenesis. Schwannomas develop from proliferation of dedifferentiated Schwann cells, which normally wrap around nerve fibers to help support and insulate nerves. In this study, we carried out high-throughput miRNA expression profiling of human vestibular schwannomas using an array representing 407 known miRNAs in order to explore the role of miRNAs in tumor growth. Twelve miRNAs were found to be significantly deregulated in tumor samples as compared with control nerve tissue, defining a schwannoma-typical signature. Among these miRNAs, we focused on miR-7 which was one of the most downregulated in these tumors and has several known oncogene targets, including mRNAs for epidermal growth factor receptor (EGFR) and p21-activated kinase 1 (Pak1). We found that overexpression of miR-7 inhibited schwannoma cell growth both in culture and in a xenograft tumor model in vivo, which correlated with downregulation of these signaling pathways. Furthermore, we identified a novel direct target of miR-7, the mRNA for associated cdc42 kinase 1 (Ack1), with the expression levels of miR-7 and Ack1 being inversely correlated in human schwannoma samples. These findings are the first analyzing miRNA profiles of schwannomas and support a “tumor suppressor” function for miR-7 in these tumors by targeting proteins in three major oncogenic pathways, EGFR, Pak1, and Ack1. Moreover, our result also suggest that miR-7 may serve as a potential therapeutic molecule for schwannomas and that drugs which inhibit these signaling pathways could suppress growth of these benign tumors. Schwannoma tumor samples are compared to nerve controls