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:Neurofibromatosis Type 1 (NF1) patients develop benign neurofibromas and malignant peripheral nerve sheath tumors (MPNST). These incurable peripheral nerve tumors result from loss of NF1 tumor suppressor gene function, causing hyperactive Ras signaling. Activated Ras controls numerous downstream effectors, but specific pathways mediating effects of hyperactive Ras in NF1 tumors are unknown. Cross-species transcriptome analyses of mouse and human neurofibromas and MPNSTs identified global negative feedback of genes that regulate Ras-Raf- MEK- extracellular signal-regulated protein kinase (ERK) signaling in both species. Nonetheless, activation of ERK was sustained in mouse and human neurofibromas and MPNST. PD0325901, a highly selective pharmacological inhibitor of MEK, was used to test whether sustained Ras-Raf-MEK-ERK signaling contributes to neurofibroma growth in the Nf1fl/fl;Dhh-cre mouse model or in NF1 patient MPNST cell xenografts. PD0325901 treatment reduced aberrantly proliferating cells in neurofibroma and MPNST, prolonged survival of mice implanted with human MPNST cells, and shrank neurofibromas in >80% of mice tested. PD0325901 also caused effects on tumor vasculature. Our data demonstrate that deregulated Ras/ERK signaling is critical for the growth of NF1 peripheral nerve tumors and provide strong rationale for testing MEK inhibitors in NF1 clinical trials. 83 microarrays: Mouse control (15), Mouse neurofibroma (15), Mouse MPNST (18); Human nerve (3), Human neurofibroma (26), Human MPNST (6) We used the same human tumor samples as in series GSE14038 (dNF, pNF and MPNST). However, instead of referencing gene expression changes to the normal human Schwann cell samples (NHSC) as we did in series GSE14038, we generated three (new) normal nerve samples (samples jan-N1-3) and referenced gene expression changes to those samples. Moreover, the analysis of series GSE14038 evaluated changes in expression between NHSC, benign tumor subtypes (dNF and pNF), and malignant tumors (MPNST), while our present submission evaluated changes between normal nerve, benign tumors (combined dNF and pNF),and malignant tumors (MPNST). The Series supplementary 'merged_data.txt' file contains the data for 9,891 transcripts that were statistically different in at least one of the two species and present in both mouse and human data sets.
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: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
Project description:No consensus treatment regime exists beyond surgery for malignant peripheral nerve sheath tumours (MPNST), and the purpose of the present study was to find new approaches to stratify patients with good and poor prognosis and to better guide therapeutic intervention for this aggressive soft tissue cancer. Genome-wide RNA expression was analysed for 30 MPNSTs and eight neurofibromas from Scandinavian patients, and the overall gene expression in these two groups were compared in order to identify prognostic markers.
Project description:Neurofibromatosis Type 1 (NF1) patients develop benign neurofibromas and malignant peripheral nerve sheath tumors (MPNST). These incurable peripheral nerve tumors result from loss of NF1 tumor suppressor gene function, causing hyperactive Ras signaling. Activated Ras controls numerous downstream effectors, but specific pathways mediating effects of hyperactive Ras in NF1 tumors are unknown. Cross-species transcriptome analyses of mouse and human neurofibromas and MPNSTs identified global negative feedback of genes that regulate Ras-Raf- MEK- extracellular signal-regulated protein kinase (ERK) signaling in both species. Nonetheless, activation of ERK was sustained in mouse and human neurofibromas and MPNST. PD0325901, a highly selective pharmacological inhibitor of MEK, was used to test whether sustained Ras-Raf-MEK-ERK signaling contributes to neurofibroma growth in the Nf1fl/fl;Dhh-cre mouse model or in NF1 patient MPNST cell xenografts. PD0325901 treatment reduced aberrantly proliferating cells in neurofibroma and MPNST, prolonged survival of mice implanted with human MPNST cells, and shrank neurofibromas in >80% of mice tested. PD0325901 also caused effects on tumor vasculature. Our data demonstrate that deregulated Ras/ERK signaling is critical for the growth of NF1 peripheral nerve tumors and provide strong rationale for testing MEK inhibitors in NF1 clinical trials.
Project description:Plexiform neurofibromas (PNF) are benign peripheral nerve sheath tumors (PNST) that arise in persons with neurofibromatosis type 1 (NF1). Despite similar histological appearance, these neoplasms proceed along diverse evolutionary trajectories, with a subset progressing to a devastating form of sarcoma called malignant peripheral nerve sheath tumor (MPNST), the leading cause of premature death in individuals with NF1. Malignant transformation of PNF often occurs through the development of atypical neurofibroma (ANF) precursor lesions characterized by distinct histopathological features and CDKN2A copy number loss. While genomic studies have improved our understanding of key driver events promoting tumor progression, the transcriptional alterations that precede malignant transformation remain poorly understood. Here we resolve gene expression profiles in PNSTs across the neurofibroma-to-MPNST continuum in NF1 patients and genetically engineered mouse models, providing insight into nascent molecular features associated with neurofibroma evolution and transformation. These findings highlight the need for molecular diagnostic tools that augment conventional histopathological criteria to identify neurofibromas at high risk of undergoing malignant transformation, facilitating risk-adapted care.
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. Benign plexiform neurofibromas have been successfully treated with selumetinib, a MEK inhibitor, but after progression to MPNST, MEK inhibition alone is not effective. Frequently, adaptive responses to single agent targeted inhibitors invokes alterations in receptor tyrosine kinase expression and feedback regulation that leads to inhibitor bypass. Here, the effects of SHP099, an inhibitor of the protein-tyrosine phosphatase SHP2 (encoded by the PTPN11 gene) was tested alone and in combination with trametinib (MEKi) in an NF1 MPNST patient derived xenograft model (PDX4) treated with SHP099, hydroxychloroquine (HCQ) or the combination. Kinase enrichment proteomic analysis was performed using tumor tissue treated with SHP099, hydroxychloroquine (HCQ) or the combination to evaluate the effects on the functional kinome.
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