Contribution of mTOR and PTEN to Radioresistance in Sporadic and NF2-Associated Vestibular Schwannomas: A Microarray and Pathway Analysis.
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PROVIDER: PRJNA594756 | ENA |
REPOSITORIES: ENA
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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.
2013-03-01 | E-GEOD-39645 | biostudies-arrayexpress
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.
2020-01-24 | GSE141801 | GEO
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.
2013-03-01 | GSE39645 | GEO
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
2014-03-24 | E-GEOD-43571 | biostudies-arrayexpress
Project description:Object: The main limitation of treatment strategies for vestibular schwannomas (VSs) is loss of function of vestibulocochlear and facial nerves, which has driven investigations into new pharmaceutical therapies. The most common genetic alteration in human VSs is loss ofthe NF2 gene which encodes the protein merlin. It is well established that merlin achieves tumor suppressive functions through regulation of the Hippo pathway. The aim of this study was to analyze dysregulation of the Hippo pathway in sporadic VSs and to identify whether Hippo signaling could be potential targetable pathway for treatment of VS. Methods: In this study, we performed gene expression profiling of ten human sporadic VSs and four normal control vestibular nerves to identify aberrant expression of the Hippo pathway in VSs. Molecular subtypes in VSs was evaluated using unsupervised hierarchical clustering analysis. Western blot analysis and immunohistochemical staining were used to examine the expression of Hippo pathway core components in twenty human sporadic VSs. NF2 gene sequencing and mutation analysis were performed in all VS samples. Ki67 marker was used to investigate proliferation of tumor cells. Verteporfin was used to determine whether the inhibitor of YAP-TEAD reduced proliferation of human primary VS cells with NF2 mutations and RT4-D6P2T cell line. Results: We found fifty-one differentially expressed genes between VSs and controls. Unsupervised analysis of transcriptional profiles identified the two distinct molecular variants, which was significantly associated with NF2 mutation status. The protein level of MST2, LAST2,phospho-LAST1, and phospho-YAP were significantly decreased in VSs compared with normal tissues. Nuclear YAP staining was positively correlated with Ki-67 indexin VS samples. Finally, verteporfin reduced viability of human primary VS cells and in a dose-dependent manner by decreasing YAP expression. Conclusions: Our findings implicate that deregulation of the Hippo pathway as a molecular mechanism of pathogenesis in human sporadic VSs, and suggest inhibition of this pathway as a potential treatment strategy.
2020-12-01 | GSE108237 | GEO
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.
2014-11-30 | GSE56596 | GEO
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.
2014-11-30 | GSE56597 | GEO
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.
2014-03-24 | GSE43571 | GEO
Project description:Neurofibromatosis type II (NF2) is a disease that needs new solutions. Vestibular schwannoma (VS) growth cause progressive hearing loss, and the standard treatment including surgery and radiotherapy, can further damage the nerve. There is an urgent need to identify an adjunct therapy that, by enhancing the efficacy of radiation, can help lower the radiation dose and preserve hearing. The mechanisms underlying deafness in NF2 are still unclear. One of the major limitations in studying tumor-induced hearing loss is the lack of mouse models that allows hearing test. Here we developed a cerebellopontine angle (CPA) schwannomas model that faithfully recapitulates the tumor-induced hearing loss. Using this model we discovered that cMET blockade by crizotinib (CRZ) enhanced schwannoma radiosensitivity by enhancing DNA damage, and CRZ treatment combined with low-dose radiation was as effective as high-dose radiation. CRZ treatment had no adverse effect on hearing; however, it did not affect tumor-induced hearing loss, presumably because cMET blockade did not change tumor HGF levels. cMET gene knockdown study independently confirmed the role of cMET pathway in mediating the effect of CRZ. Furthermore, we evaluated the translational potential of cMET blockade in human schwannomas. We found that human NF2-associated and sporadic VSs showed significantly elevated HGF expression and cMET activation compared to normal nerves, which correlated with tumor growth and cyst formation. Using organoid brain slice culture, cMET blockade inhibited the growth of patient-derived schwannomas. Our findings provide the rationale and necessary data for the clinical translation of combined cMET blockade with radiation therapy in NF2 patients. We found that human NF2-associated and sporadic VSs showed significantly elevated HGF expression and cMET activation compared to normal nerves, which correlated with tumor growth and cyst formation.
2018-06-26 | GSE108524 | GEO
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.
| S-EPMC7016954 | biostudies-literature