Project description:Genome-wide DNA methylation profiling of 22 schwannomas belonging to three different genotypes (NF2-mutant, SOX10-mutant, and HTRA1-fused). The Illumina Infinium EPIC 850k Human DNA Methylation Beadchip was used to obtain DNA methylation profiles across approximately 850,000 CpG sites of genomic DNA extracted from formalin-fixed, paraffin-embedded tumor tissue of 22 schwannomas.
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:Genome-wide DNA methylation profiling of 6 schwannomas arising as part of segmental schwannomatosis due to somatic mosaic SOX10 indel mutations. The Illumina Infinium EPIC 850k Human DNA Methylation Beadchip was used to obtain DNA methylation profiles across approximately 850,000 CpG sites of genomic DNA extracted from formalin-fixed, paraffin-embedded tumor tissue of 6 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.
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