RESUMO
Neurofibromatosis type 1, including the highly aggressive malignant peripheral nerve sheath tumors (MPNSTs), is featured by the loss of functional neurofibromin 1 (NF1) protein resulting from genetic alterations. A major function of NF1 is suppressing Ras activities, which is conveyed by an intrinsic GTPase-activating protein-related domain (GRD). In this study, we explored the feasibility of restoring Ras GTPase via exogenous expression of various GRD constructs, via gene delivery using a panel of adeno-associated virus (AAV) vectors in MPNST and human Schwann cells (HSCs). We demonstrated that several AAV serotypes achieved favorable transduction efficacies in those cells and a membrane-targeting GRD fused with an H-Ras C-terminal motif (C10) dramatically inhibited the Ras pathway and MPNST cells in a NF1-specific manner. Our results opened up a venue of gene replacement therapy in NF1-related tumors.
Assuntos
Dependovirus/genética , Terapia Genética/métodos , Neurofibromatose 1/terapia , Neurofibromina 1/genética , Linhagem Celular , Linhagem Celular Tumoral , Células Cultivadas , Estudos de Viabilidade , Vetores Genéticos/genética , Humanos , Neurofibromina 1/química , Neurofibromina 1/metabolismo , Domínios Proteicos , Células de Schwann/metabolismo , Proteínas ras/genética , Proteínas ras/metabolismoRESUMO
Schwannomas are common, highly morbid and medically untreatable tumors that can arise in patients with germ line as well as somatic mutations in neurofibromatosis type 2 (NF2). These mutations most commonly result in the loss of function of the NF2-encoded protein, Merlin. Little is known about how Merlin functions endogenously as a tumor suppressor and how its loss leads to oncogenic transformation in Schwann cells (SCs). Here, we identify nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)-inducing kinase (NIK) as a potential drug target driving NF-κB signaling and Merlin-deficient schwannoma genesis. Using a genomic approach to profile aberrant tumor signaling pathways, we describe multiple upregulated NF-κB signaling elements in human and murine schwannomas, leading us to identify a caspase-cleaved, proteasome-resistant NIK kinase domain fragment that amplifies pathogenic NF-κB signaling. Lentiviral-mediated transduction of this NIK fragment into normal SCs promotes proliferation, survival, and adhesion while inducing schwannoma formation in a novel in vivo orthotopic transplant model. Furthermore, we describe an NF-κB-potentiated hepatocyte growth factor (HGF) to MET proto-oncogene receptor tyrosine kinase (c-Met) autocrine feed-forward loop promoting SC proliferation. These innovative studies identify a novel signaling axis underlying schwannoma formation, revealing new and potentially druggable schwannoma vulnerabilities with future therapeutic potential.
Assuntos
Neurilemoma/genética , Neurofibromatose 2/genética , Neurofibromina 2/genética , Proteínas Serina-Treonina Quinases/genética , Animais , Comunicação Autócrina/genética , Carcinogênese/genética , Caspase 1/genética , Proliferação de Células/genética , Modelos Animais de Doenças , Regulação Neoplásica da Expressão Gênica , Fator de Crescimento de Hepatócito/genética , Humanos , Camundongos , Terapia de Alvo Molecular , NF-kappa B/genética , Neurilemoma/complicações , Neurilemoma/tratamento farmacológico , Neurilemoma/patologia , Neurofibromatose 2/complicações , Neurofibromatose 2/tratamento farmacológico , Neurofibromatose 2/patologia , Complexo de Endopeptidases do Proteassoma/genética , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas c-met/genética , Células de Schwann , Transdução de Sinais/genética , Quinase Induzida por NF-kappaBRESUMO
Neurofibromatosis type 2 (NF2) is an autosomal dominant genetic disorder resulting from germline mutations in the NF2 gene. Bilateral vestibular schwannomas, tumors on cranial nerve VIII, are pathognomonic for NF2 disease. Furthermore, schwannomas also commonly develop in other cranial nerves, dorsal root ganglia and peripheral nerves. These tumors are a major cause of morbidity and mortality, and medical therapies to treat them are limited. Animal models that accurately recapitulate the full anatomical spectrum of human NF2-related schwannomas, including the characteristic functional deficits in hearing and balance associated with cranial nerve VIII tumors, would allow systematic evaluation of experimental therapeutics prior to clinical use. Here, we present a genetically engineered NF2 mouse model generated through excision of the Nf2 gene driven by Cre expression under control of a tissue-restricted 3.9kbPeriostin promoter element. By 10 months of age, 100% of Postn-Cre; Nf2(flox/flox) mice develop spinal, peripheral and cranial nerve tumors histologically identical to human schwannomas. In addition, the development of cranial nerve VIII tumors correlates with functional impairments in hearing and balance, as measured by auditory brainstem response and vestibular testing. Overall, the Postn-Cre; Nf2(flox/flox) tumor model provides a novel tool for future mechanistic and therapeutic studies of NF2-associated schwannomas.