The transcriptomic signature of painful and non-painful human NF2 schwannomas [set2]
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ABSTRACT: Schwannomas are benign peripheral nerve sheath tumors that are associated with substantial morbidity including severe, persistent pain. Treatment, essentially limited to surgical resection, is associated with significant morbidity and for many patient’s efficacious treatment of tumor-related pain is not achievable. There is an urgent need to elucidate the molecular mechanisms underlying schwannoma-induced pain as a first step in development of new therapeutics. In this study, we performed next-generation RNASequencing on a small cohort of formalin fixed paraffin-embedded, painful, and non-painful schwannoma samples obtained from Neurofibromatosis type 2 (NF2) patients. Differential gene and isoform level expression analysis revealed significant transcriptomic differences between painful and non-painful tumors; differentially regulated genes included members of the fibroblast growth factor (FGF) family of genes. Using a xenograft model of human-NF2 we demonstrated that over-expression of FGF7 in schwannoma cells was associated with the development of pain-like behaviors. These results demonstrate both the value of RNASeq utilizing formalin fixed tissues and reveal a novel pathway responsible for neoplasm-associated pain.
Project description:Schwannomas are benign peripheral nerve sheath tumors that are associated with substantial morbidity including severe, persistent pain. Treatment, essentially limited to surgical resection, is associated with significant morbidity and for many patient’s efficacious treatment of tumor-related pain is not achievable. There is an urgent need to elucidate the molecular mechanisms underlying schwannoma-induced pain as a first step in development of new therapeutics. In this study, we performed next-generation RNASequencing on a small cohort of formalin fixed paraffin-embedded, painful, and non-painful schwannoma samples obtained from Neurofibromatosis type 2 (NF2) patients. Differential gene and isoform level expression analysis revealed significant transcriptomic differences between painful and non-painful tumors; differentially regulated genes included members of the fibroblast growth factor (FGF) family of genes. Using a xenograft model of human-NF2 we demonstrated that over-expression of FGF7 in schwannoma cells was associated with the development of pain-like behaviors. These results demonstrate both the value of RNASeq utilizing formalin fixed tissues and reveal a novel pathway responsible for neoplasm-associated pain.
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:This work describes the DNA methylation signature and identifies genes associated with neuropathic pain in type 2 diabetes mellitus. Genome-wide methylation data for 315 DNA (WB) samples were generated using Illumina Infinium Methylation EPIC v1.0 BeadChip. Four different selection criteria were used to identify promising pain-related genes. The findings revealed significant differences in methylation patterns between painful and painless diabetic neuropathy and identified a set of individual CpG sites of unique candidate genes associated with the painful phenotype. Several of these genes, including GCH1, MYT1L and MED16, have been previously linked to pain-related phenotypes or diabetes. Through pathway enrichment analysis, we demonstrated that specific epigenetic signatures could contribute to the complex phenotype of diabetic neuropathy and cluster analyses highlighted significant epigenetic dissimilarities between painful and painless phenotypes. Our results uncovered epigenetic differences between painful and painless diabetic neuropathy patients and identified targeted genes linked to neuropathic pain through DNA methylation mechanisms. This approach holds promise for investigating other chronic pain conditions, such as secondary chronic pain from cancer treatment, thoracic surgery, and various transplant settings.
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:The use of radiation treatment has increased for both sporadic and neurofibromatosis type 2 (NF2)-associated vestibular schwannoma (VS). However, there are a subset of radioresistant tumors and systemic treatments that are seldom used in these patients. We investigated molecular alterations after radiation in three NF2-associated and five sporadically operated recurrent VS after primary irradiation. We compared these findings with 49 non-irradiated (36 sporadic and 13 NF2-associated) VS through gene-expression profiling and pathway analysis. Furthermore, we stained the key molecules of the distinct pathway by immunohistochemistry. A total of 195 differentially expressed genes in sporadic and NF2-related comparisons showed significant differences based on the criteria of p value < 0.05 and a two-fold change. These genes were involved in pathways that are known to be altered upon irradiation (e.g., mammalian target of rapamycin (mTOR), phosphatase and tensin homolog (PTEN) and vascular endothelial growth factor (VEGF) signaling). We observed a combined downregulation of PTEN signaling and an upregulation of mTOR signaling in progressive NF2-associated VS after irradiation. Immunostainings with mTOR and PTEN antibodies confirmed the respective molecular alterations. Taken together, mTOR inhibition might be a promising therapeutic strategy in NF2-associated VS progress after irradiation.
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