Project description:22 plexiform neurofibromas from 18 unrelated neurofibromatosis-type 1 patients were screened with a high resolution array-CGH. Each PNF DNA (somatic tumor DNA) was individually hybridized on Agilent whole human genome 244K microarrays (Platform GPL4091) using the matched genomic constitutional DNA (lymphocytes DNA) from the corresponding patient as reference, in order to detect tumor-specific aberrations. NF1-associated plexiform neurofibromas DNA vs. constitutional DNA
Project description:Plexiform neurofibromas (PN) are benign nerve sheath Schwann cell tumors, common in patients with neurofibromatosis type 1 (NF1), that are characterized by biallelic mutations in the NF1 tumor suppressor gene. Atypical neurofibromas (ANF) show additional frequent loss of CDKN2A/Ink4a/Arf and may be precursor lesions of aggressive malignant peripheral nerve sheath tumors (MPNST). We combined loss of Nf1 in developing
Project description:Patients carrying an inactive NF1 allele develop tumours of Schwann cell origin called neurofibromas (NFs). Genetically engineered mouse models have significantly enriched our understanding of plexiform forms of NFs (pNFs). However, this has not been the case for cutaneous neurofibromas (cNFs), observed in all NF1 patients, as no previous model recapitulates their development. Here, we show that conditional Nf1 inactivation in Prss56-positive boundary cap cells leads to bona fide pNFs and cNFs. This work identifies subepidermal glia as a likely candidate for the cellular origin of cNFs, and provides insights on disease mechanisms, revealing a long, multistep pathological process in which inflammation play pivotal role. This new mouse model is an important asset for future clinical and therapeutic investigations of NF1-associated neurofibromas.
Project description:Malignant peripheral nerve sheath tumors (MPNSTs) are the leading cause of premature death for patients with Neurofibromatosis type 1 and no approved targeted therapies are available. Transformation from Nf1-null benign plexiform neurofibromas is driven by the loss of the Cdkn2a (Arf) locus. Here, genetically engineered mouse models with combined Nf1 flox/flox and Arf flox/flox alleles were used (crossed with Postn-Cre+ mice). Tissue from MPNSTs that form in the Nf1-/-;Arf-/- setting were used for mRNA sequencing and compared to benign plexiform neurofibroma tissue (Nf1-/- from Nf1 flox/flox; Postn-Cre+ mice, GSE213789) to identify transcriptome signatures from MPNST and compare them to benign plexiform neurofibroma.
Project description:Patients with neurofibromatosis type 1 (NF1) develop benign plexiform neurofibromas that frequently progress to become malignant peripheral nerve sheath tumors (MPNSTs). A genetically engineered mouse model that accurately models plexiform neurofibroma-MPNST progression would facilitate the identification of somatic mutations driving this process. We have previously reported that transgenic mice overexpressing the growth factor neuregulin-1 in Schwann cells (P0-GGF?3 mice) develop MPNSTs. To determine whether P0-GGF?3 mice accurately model neurofibroma-MPNST progression, cohorts of these animals were followed to death and necropsied. 94% of the mice developed multiple neurofibromas, with 70% carrying smaller numbers of MPNSTs; nascent MPNSTs were identified within neurofibromas, suggesting that these sarcomas arise from neurofibromas. Although neurofibromin expression was maintained, P0-GGF?3 MPNSTs, like human NF1-associated MPNSTs, demonstrated Ras hyperactivation. P0-GGF?3 MPNSTs also showed abnormalities in the p16INK4A-cyclin D/CDK4-Rb and p19ARF-Mdm-p53 pathways analogous to their human counterparts. Array comparative genomic hybridization (CGH) demonstrated reproducible chromosomal alterations in P0-GGF?3 MPNST cells (including universal chromosome 11 gains) and focal gains and losses affecting 39 genes previously implicated in neoplasia (e.g., Pten, Tpd52, Myc , Gli1, Xiap, Bbc3/PUMA). Array CGH also identified recurrent focal copy number variations affecting genes not previously linked to neurofibroma or MPNST pathogenesis. We conclude that P0-GGF?3 mice represent a robust model of neurofibroma-MPNST progression that can be used to identify novel genes driving neurofibroma and MPNST pathogenesis. Array CGH comparison of malignant peripheral nerve sheath tumor (MPNST) cells vs non-neoplastic Schwann cells
Project description:Understanding biological pathways critical for common neurofibromatosis type 1 (NF1) peripheral nerve tumors is essential, as tumor biomarkers, prognostic factors and therapeutics are all lacking. We used gene expression profiling to define transcriptional changes between primary normal Schwann cells (n = 10), NF1-derived primary benign neurofibroma Schwann cells (n = 22), malignant peripheral nerve sheath tumor (MPNST) cell lines (n = 13), benign neurofibromas (n = 26) and MPNST (n = 6). Dermal and plexiform neurofibromas were indistinguishable. A prominent theme in the analysis was aberrant differentiation. Neurofibromas repressed gene programs normally active in Schwann cell precursors and immature Schwann cells. MPNST signatures strongly differed; genes upregulated in the sarcomas were significantly enriched for genes activated in neural crest cells. We validated differential expression of 82 genes including the neural crest transcription factor SOX9 and SOX9 predicted targets. SOX9 immunoreactivity was robust in neurofibroma and MPSNT tissue sections and targeting SOX9 - strongly expressed in NF1-related tumors - caused MPNST cell death. SOX9 is a biomarker of neurofibroma and MPNST, and possibly a therapeutic target in NF1. Keywords: tumor stage 86 microarrays, consisting of 77 samples and 9 batch reference samples: NHSC (10), dNFSC (11), pNFSC (11), MPNST cell lines (13), dNF (13), pNF (13), MPNST (6)
Project description:The MEK inhibitor selumetinib induces objective responses and provides clinical benefit in children with neurofibromatosis type 1 (NF1) and inoperable plexiform neurofibromas (PNs). To evaluate whether similar outcomes were possible in adult patients, in whom PN growth is generally slower than in pediatric patients, an open-label phase 2 study of selumetinib in adults with NF1 PNs was conducted. Correlative analysis included extraction of RNA followed by sequencing. Samples include paired specimens collected before and on treatment.
Project description:Patients with neurofibromatosis type 1 (NF1) develop benign plexiform neurofibromas that frequently progress to become malignant peripheral nerve sheath tumors (MPNSTs). A genetically engineered mouse model that accurately models plexiform neurofibroma-MPNST progression would facilitate the identification of somatic mutations driving this process. We have previously reported that transgenic mice overexpressing the growth factor neuregulin-1 in Schwann cells (P0-GGFβ3 mice) develop MPNSTs. To determine whether P0-GGFβ3 mice accurately model neurofibroma-MPNST progression, cohorts of these animals were followed to death and necropsied. 94% of the mice developed multiple neurofibromas, with 70% carrying smaller numbers of MPNSTs; nascent MPNSTs were identified within neurofibromas, suggesting that these sarcomas arise from neurofibromas. Although neurofibromin expression was maintained, P0-GGFβ3 MPNSTs, like human NF1-associated MPNSTs, demonstrated Ras hyperactivation. P0-GGFβ3 MPNSTs also showed abnormalities in the p16INK4A-cyclin D/CDK4-Rb and p19ARF-Mdm-p53 pathways analogous to their human counterparts. Array comparative genomic hybridization (CGH) demonstrated reproducible chromosomal alterations in P0-GGFβ3 MPNST cells (including universal chromosome 11 gains) and focal gains and losses affecting 39 genes previously implicated in neoplasia (e.g., Pten, Tpd52, Myc , Gli1, Xiap, Bbc3/PUMA). Array CGH also identified recurrent focal copy number variations affecting genes not previously linked to neurofibroma or MPNST pathogenesis. We conclude that P0-GGFβ3 mice represent a robust model of neurofibroma-MPNST progression that can be used to identify novel genes driving neurofibroma and MPNST pathogenesis.