Gene expression changes in HEI-193 (NF2-deficient Schwannoma) cells by NF2-restoring or TEW7197 treatment.
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ABSTRACT: Neurofibromatosis type 2 (NF2) syndrome is a very rare human genetic disease and until now, it’s proper treatment has not been suggested. In our recent study, it has been reported that the loss of NF2 activates MAPK signaling through reduction of RKIP in a mesothelioma model. Here, we show that loss of NF2 induces reduction of the TGF-β receptor 2 (TβR2) expression and an overwhelming expression of TGF-β receptor 1 is activated by physical stimuli such as pressure or heavy materials. Activated TR1 induced the phosphorylation and degradation of RKIP. RKIP reduction consequently results in MAPK activation as well as Snail-mediated p53 suppression and occurrence of EMT in NF2-deficient cells by physical stimuli. Thus, TβR1 kinase inhibitors restore cell differentiation and induce growth suppression in NF2 deficient Schwannoma cell line and MEF. Moreover, TEW7197, a specific TβR1 kinase inhibitor, reduces tumor formation in the NF2-model mouse (Postn-Cre;NF2f/f). Gene expression profiling reveals that TEW7197-treatment induces the expression of lipid metabolism-related gene set such as NF2-restored cells in HEI-193 (NF2-deficient Schwannoma). Our results indicate that reduction or deletion of TβR2 or NF2 induces the TβR1-mediated oncogenic pathway, and therefore inhibition of the unbalanced TGF-β signaling is a putative strategy for NF2-related cancers (NF2 syndrome and mesothelioma) and TβR2 mutated advanced cancers. To know the global effect of TEW7197, we performed the microarray with HEI-193.
Project description:Loss of NF2 (merlin) has been suggested as a genetic cause of neurofibromatosis type 2 and malignant peripheral nerve sheath tumor (MPNST). Previously, we demonstrated that NF2 sustained TGF- receptor 2 (TR2) expression and reduction or loss of NF2 activated non-canonical TGF- signaling, which reduced RKIP expression via TR1 kinase activity. Here, we show that a selective RKIP inducer (novel chemical, Nf18001) inhibits tumor growth and promotes schwannoma cell differentiation into mature Schwann cells under NF2-deficient conditions. In addition, Nf18001 is not cytotoxic to cells expressing NF2 and is not disturb canonical TGF- signaling. Moreover, the novel chemical induces expression of SOX10, a marker of differentiated Schwann cells, and promotes nuclear export and degradation of SOX2, a stem cell factor. Treatment with Nf18001 inhibited tumor growth in an allograft model with mouse schwannoma cells. These results strongly suggest that selective RKIP inducers could be useful for the treatment of neurofibromatosis type 2 as well as NF2-deficient MPNST. To know the global effect of Nf18001, we performed the microarray with HEI-193.
Project description:Since loss of the NF2 tumor suppressor gene results in p21-activated kinase (Pak) activation, PAK inhibitors hold promise for the treatment of NF2-deficient tumors. To test this possibility, we asked if loss of Pak2, a highly expressed group I PAK member, affects the development of malignant mesothelioma in Nf2;Cdkn2a-deficient (NC) mice and the growth properties of NC mesothelioma cells in culture. In vivo, deletion of Pak2 resulted in a markedly decreased incidence and delayed onset of both pleural and peritoneal malignant mesotheliomas in NC mice. In vitro, Pak2 deletion decreased malignant mesothelioma cell viability, migration, clonogenicity, and spheroid formation. RNA-seq analysis demonstrated downregulated expression of Hedgehog and Wnt pathway genes in NC;Pak2-/- mesothelioma cells versus NC;Pak2+/+ mesothelioma cells. Targeting of the Hedgehog signaling component Gli1 or its target gene Myc inhibited cell viability and spheroid formation in NC;P+/+ mesothelioma cells. Kinome profiling uncovered kinase changes indicative of EMT in NC;Pak2-/- mesothelioma cells, suggesting that Pak2-deficient malignant mesotheliomas can adapt by reprogramming their kinome in the absence of Pak activity. The identification of such compensatory pathways offers opportunities for rational combination therapies to circumvent resistance to anti-PAK drugs.
Project description:Treatment of multiple intracranial schwannomas in patient with neurofibromatosis type 2 (NF2) is extremely unsatisfactory and innovative therapeutic approaches are urgently needed. The lack of clinically relevant NF2 models has severely hampered drug discovery in this rare disease. Here, we report for the first time the establishment and characterization of patient-derived xenograft (PDX) and cell line models of NF2-associated schwannoma, which retain the gene mutations and transcriptome profile, and recapitulate the morphological and histopathological features with the patient tumors, retain patient NF2 mutations, and maintain gene expression profiles resembling the patient tumor profiles with the preservation of multiple key signaling pathways commonly dysregulated in human schwannoma. Using expression profiling, we found that the PI3K/AKT/mTOR networks are elevated in NF2-associated vestibular schwannomas, as well as in PDX models.
Project description:Current models imply that the FERM domain protein Merlin, encoded by the tumor suppressor NF2, inhibits mitogenic signaling at or near the plasma membrane. Here, we show that the closed, growth inhibitory form of Merlin accumulates in the nucleus, binds to the E3 ubiquitin ligase CRL4DCAF1, and suppresses its activity. Depletion of DCAF1 blocks the promitogenic effect of inactivation of Merlin. Conversely, enforced expression of a Merlin-insensitive mutant of DCAF1 counteracts the antimitogenic effect of Merlin. Re-expression of Merlin and silencing of DCAF1 induce a similar, tumor-suppressive program of gene expression. Tumor-derived mutations invariably disrupt Merlinâs ability to interact with or inhibit CRL4DCAF1. Finally, depletion of DCAF1 inhibits the hyperproliferation of Schwannoma cells from NF2 patients and suppresses the oncogenic potential of Merlin-deficient tumor cell lines. We propose that Merlin suppresses tumorigenesis by translocating to the nucleus to inhibit CRL4DCAF1. To examine if Merlin controls gene expression through inhibition of CRL4DCAF1, and define the general function of this ligase, we compared the gene expression program activated by expression of Merlin or by depletion of DCAF1 in Merlin-null FC-1801 mouse Schwannoma cells
Project description:Schwannomas are benign peripheral nerve sheath tumors that are associated with substantial morbidity including severe, persistent pain. Treatment, essentially limited to surgical resection, is associated with significant morbidity and for many patient’s efficacious treatment of tumor-related pain is not achievable. There is an urgent need to elucidate the molecular mechanisms underlying schwannoma-induced pain as a first step in development of new therapeutics. In this study, we performed next-generation RNASequencing on a small cohort of formalin fixed paraffin-embedded, painful, and non-painful schwannoma samples obtained from Neurofibromatosis type 2 (NF2) patients. Differential gene and isoform level expression analysis revealed significant transcriptomic differences between painful and non-painful tumors; differentially regulated genes included members of the fibroblast growth factor (FGF) family of genes. Using a xenograft model of human-NF2 we demonstrated that over-expression of FGF7 in schwannoma cells was associated with the development of pain-like behaviors. These results demonstrate both the value of RNASeq utilizing formalin fixed tissues and reveal a novel pathway responsible for neoplasm-associated pain.
Project description:Schwannomas are benign peripheral nerve sheath tumors that are associated with substantial morbidity including severe, persistent pain. Treatment, essentially limited to surgical resection, is associated with significant morbidity and for many patient’s efficacious treatment of tumor-related pain is not achievable. There is an urgent need to elucidate the molecular mechanisms underlying schwannoma-induced pain as a first step in development of new therapeutics. In this study, we performed next-generation RNASequencing on a small cohort of formalin fixed paraffin-embedded, painful, and non-painful schwannoma samples obtained from Neurofibromatosis type 2 (NF2) patients. Differential gene and isoform level expression analysis revealed significant transcriptomic differences between painful and non-painful tumors; differentially regulated genes included members of the fibroblast growth factor (FGF) family of genes. Using a xenograft model of human-NF2 we demonstrated that over-expression of FGF7 in schwannoma cells was associated with the development of pain-like behaviors. These results demonstrate both the value of RNASeq utilizing formalin fixed tissues and reveal a novel pathway responsible for neoplasm-associated pain.
Project description:Here we describe a mouse model of mesothelioma with combined deletion of Bap1, Nf2, and Cdkn2ab that shows rapid onset and recapitulates human mesothelioma including its response to the standard treatment. This autochthonous model should be attractive for testing cancer immunotherapies.
Project description:Neurofibromatosis type 2 is an inherited neoplastic disease consisting of schwannomas, meningiomas, and ependymomas that is caused by inactivation of the tumor suppressor gene NF2. The NF2 gene product, merlin, has no intrinsic catalytic activity; its tumor suppressor function is mediated through the proteins with which it interacts. However, there is no consensus about which merlin interactions are necessary for tumor suppression. We used proximity biotinylation followed by mass spectrometry and direct binding assays to characterize the proteins that associate with merlin and merlin mutants in immortalized Schwann cells. We identified 52 proteins that associate with merlin, including a previously unreported merlin binding protein, ASPP2. Our results identify merlin as a component of mechanosensing signal transduction pathways in cell junctions, in the context of a specific set of structures and molecules through which it acts, in a cell type relevant to schwannoma formation.