Project description:Background: Malignant peripheral nerve sheath tumors (MPNST) are soft-tissue sarcomas that can arise either sporadically or in association with neurofibromatosis type 1 (NF1). These aggressive malignancies confer poor survival, with no effective therapy available. Methods: We generated five patient-derived MPNST orthoxenograft models (three NF1-related and two sporadic) and performed an exhaustive histological and molecular characterization of primary MPNSTs and their corresponding orthoxenografts. Finally, orthoxenografts models were used as an in vivo pre-clinical platform to test several treatment strategies. Results: MPNST orthoxenografts recapitulate the histopathological properties and preserve the genomic and transcriptomic status of their parental primary tumors. Additionally, they mimic distal dissemination properties in mice. Compatible with an origin in a catastrophic event and subsequent stabilization, MPNSTs contained highly altered genomes that remained remarkably stable in orthoxenograft establishment and along passages. Although preliminary, the results presented here point to clear differences between NF1-associated and sporadic MPNSTs. In accordance, mutation frequency in sporadic MPNSTs was an order of magnitude higher than in NF1-associated MPNSTs and unsupervised cluster analysis and principal component analysis (PCA) using a MPNST signature perfectly divided the samples between NF1 and sporadic MPNST. Finally, different therapeutic approaches tested in the validated orthoxenograft MPNST models, reveal that sorafenib, or in combination with doxorubicin or rapamycin caused a great tumor reduction in all models. Conclusion: The development of a well-characterized and standardized preclinical model for MPNSTs has laid the foundations for evaluating novel therapeutic strategies in the clinical setting. Moreover, results obtained strongly support the clinical evaluation of Sorafenib in this subset of patients. Primary MPNSTs were implanted in the sciatic nerve of nude mices to create orthoxenograft MPNST models. Several orthoxenograft passages were created. The primary tumor (when available) and passages 1 and 4 were selected for gene expression profiling to demonstrate that the orthoxenografts closely resemble their primary tumors and are stable along xenograft passages.
Project description:Background: Malignant peripheral nerve sheath tumors (MPNST) are soft-tissue sarcomas that can arise either sporadically or in association with neurofibromatosis type 1 (NF1). These aggressive malignancies confer poor survival, with no effective therapy available. Methods: We generated five patient-derived MPNST orthoxenograft models (three NF1-related and two sporadic) and performed an exhaustive histological and molecular characterization of primary MPNSTs and their corresponding orthoxenografts. Finally, orthoxenografts models were used as an in vivo pre-clinical platform to test several treatment strategies. Results: MPNST orthoxenografts recapitulate the histopathological properties and preserve the genomic and transcriptomic status of their parental primary tumors. Additionally, they mimic distal dissemination properties in mice. Compatible with an origin in a catastrophic event and subsequent stabilization, MPNSTs contained highly altered genomes that remained remarkably stable in orthoxenograft establishment and along passages. Although preliminary, the results presented here point to clear differences between NF1-associated and sporadic MPNSTs. In accordance, mutation frequency in sporadic MPNSTs was an order of magnitude higher than in NF1-associated MPNSTs and unsupervised cluster analysis and principal component analysis (PCA) using a MPNST signature perfectly divided the samples between NF1 and sporadic MPNST. Finally, different therapeutic approaches tested in the validated orthoxenograft MPNST models, reveal that sorafenib, or in combination with doxorubicin or rapamycin caused a great tumor reduction in all models. Conclusion: The development of a well-characterized and standardized preclinical model for MPNSTs has laid the foundations for evaluating novel therapeutic strategies in the clinical setting. Moreover, results obtained strongly support the clinical evaluation of Sorafenib in this subset of patients.
Project description:Malignant peripheral nerve sheath tumors (MPNST) are aggressive cancers that occur spontaneously (sporadic MPNST) or from pre-existing, benign plexiform neurofibromas in neurofibromatosis type 1 (NF1) patients. MPNSTs metastasize easily, are resistant to therapeutic intervention and are frequently fatal. The molecular changes underlying the transition to malignancy in the NF1 setting are incompletely understood. Here we investigate the involvement of microRNAs in this process. Using an RT-PCR platform microRNA expression profiles were determined from a unique series of archival paired samples of plexiform neurofibroma and MPNST. At least 90 differentially expressed microRNAs (p<0.025; FDR<10%) were identified between the paired samples. Most microRNAs (91%) were found downregulated and 9% of the microRNAs were upregulated in MPNST. Based on the fold changes and statistical significance three downregulated microRNAs (let-7b-5p, miR-143-3p, miR-145-5p) and two upregulated microRNAs (miR135b-5p and miR-889-3p) were selected for further functional characterization. Their expression levels were validated in a relevant cell line panel and a series of unpaired fresh frozen tumor samples containing plexiform neurofibromas, atypical neurofibromas and MPNSTs. As part of the validation process we also determined and analyzed microRNA expression profiles of sporadic MPNSTs observing that microRNA expression discriminates NF1-associated and sporadic MPNSTs emphasizing their different etiologies. The involvement of microRNAs in tumorigenesis and cancer progression was examined in NF1-derived MPNST cell lines through modulating microRNA levels by transient transfection of microRNA mimics or inhibitors. The effects of microRNAs on cellular proliferation, migration, invasion and Wnt/ẞ-catenin signaling were determined. Our findings indicate that, some of the selected microRNAs affect migratory and invasive capabilities and Wnt signaling activity. It was observed that the functional effects upon microRNA modulation are distinct in different cell lines. From our study we conclude that miRNAs play essential regulatory roles in MPNST facilitating tumor progression.
Project description:Malignant peripheral nerve sheath tumors (MPNST) are aggressive cancers that occur spontaneously (sporadic MPNST) or from pre-existing, benign plexiform neurofibromas in neurofibromatosis type 1 (NF1) patients. MPNSTs metastasize easily, are resistant to therapeutic intervention and are frequently fatal. The molecular changes underlying the transition to malignancy in the NF1 setting are incompletely understood. Here we investigate the involvement of microRNAs in this process. Using an RT-PCR platform microRNA expression profiles were determined from a unique series of archival paired samples of plexiform neurofibroma and MPNST. At least 90 differentially expressed microRNAs (p<0.025; FDR<10%) were identified between the paired samples. Most microRNAs (91%) were found downregulated and 9% of the microRNAs were upregulated in MPNST. Based on the fold changes and statistical significance three downregulated microRNAs (let-7b-5p, miR-143-3p, miR-145-5p) and two upregulated microRNAs (miR135b-5p and miR-889-3p) were selected for further functional characterization. Their expression levels were validated in a relevant cell line panel and a series of unpaired fresh frozen tumor samples containing plexiform neurofibromas, atypical neurofibromas and MPNSTs. As part of the validation process we also determined and analyzed microRNA expression profiles of sporadic MPNSTs observing that microRNA expression discriminates NF1-associated and sporadic MPNSTs emphasizing their different etiologies. The involvement of microRNAs in tumorigenesis and cancer progression was examined in NF1-derived MPNST cell lines through modulating microRNA levels by transient transfection of microRNA mimics or inhibitors. The effects of microRNAs on cellular proliferation, migration, invasion and Wnt/ẞ-catenin signaling were determined. Our findings indicate that, some of the selected microRNAs affect migratory and invasive capabilities and Wnt signaling activity. It was observed that the functional effects upon microRNA modulation are distinct in different cell lines. From our study we conclude that miRNAs play essential regulatory roles in MPNST facilitating tumor progression.
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.
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:Comparison of copy number changes in MPNST samples against benign neurofibromas in NF1 patients 24 MPNSTs and 3 NF samples were hybridised to the human 32K BAC tiling path array
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas and the primary cause of mortality in patients with neurofibromatosis type 1 (NF1). These malignancies develop within pre-existing benign lesions called plexiform neurofibromas (PNs). PNs are solely driven by biallelic NF1 loss eliciting RAS pathway activation and respond favorably to MEK inhibitor therapy. MPNSTs harbor additional mutations and respond poorly to MEK inhibition. Our analysis of genetically engineered and orthotopic patient-derived xenograft MPNST tumor models indicates that MEK inhibition has poor anti-tumor efficacy. By contrast, upstream inhibition of RAS through the protein-tyrosine phosphatase SHP2 reduced downstream signaling and suppressed NF1 MPNST growth, although resistance eventually emerged. To investigate possible mechanisms of acquired resistance, kinomic analyses of resistant tumors was performed, and data analysis identified enrichment of activated autophagy pathway protein kinases. Combining SHP2 inhibition with hydroxychloroquine resulted in durable responses in NF1 MPNSTs in both genetic and orthotopic xenograft mouse models. Our studies could be rapidly translated into a clinical trial to evaluate SHP2 inhibition in conjunction with hydroxychloroquine as a novel treatment approach for NF1 MPNSTs.