Project description: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:Merlin is the tumor suppressor protein encoded by the NF2 gene. The expression of Merlin is remarkably decreased in metastatic breast cancer tissues irrespective of the breast cancer subtype. In order to ascribe clinical relevance, we re-capitulated the loss of Merlin in breast cancer cells. Merlin deficiency elicited a markedly invasive phenotype. In order to overcome the challenge of embryonic lethality of a total Nf2-knockout, we generated a unique mammary-specific Nf2-knockout mouse mammary tumor model. Both, the Nf2-knockout mouse embryonic fibroblasts (MEF) and Merlin-deficient breast tumor cells displayed a robust invasive phenotype. Transcriptomic assessment of Nf2-knockout MEFs revealed notable alterations in glutathione transferase and antioxidant networks indicating a role for Merlin in redox biology. This programmatic alteration resonated with the pathways that emerged from breast tumor cells engineered for Merlin deficiency.
Project description:The NF2 gene, which encodes the Merlin protein, is a bona fide tumor suppressor whose mutations underlie inherited tumor syndrome Neurofibromatosis Type 2 (NF2). Recent large-scale genome sequencing studies have also identified NF2 as one of the most frequently mutated genes in VHL-wild-type kidney cancers. Even though a wide array of downstream signaling pathways has been described for Merlin/NF2, the molecular mechanisms underpinning the growth and survival of NF2 mutant tumors remain poorly understood. Using an inducible orthotopic kidney tumor model, we demonstrate for the first time that silencing of YAP/TAZ is sufficient to induce regression of pre-established NF2 deficient kidney tumors. Mechanistically, we show that YAP/TAZ ablation severely diminishes glycolysis by downregulating the transcription of several glycolytic enzymes and growth factors and RTK-PI3K-AKT signaling, resulting in growth arrest. On the other hand, YAP/TAZ depletion significantly increases mitochondrial respiration and overproduction of mitochondrial ROS, resulting in redox imbalance and oxidative stress cell death when challenged by nutrient stress. Furthermore, we identify lysosome-mediated cAMP-PKA/EPACdependent activation of the RAF-MEK-ERK pathway to be a novel resistance mechanism that allows NF2 deficient tumor cells to survive YAP/TAZ inhibition in vitro and in vivo. Finally, unbiased analysis of TCGA primary kidney tumor transcriptomes confirms strong correlations of a YAP/TAZ signature with the expression of glycolysis, oxidative phosphorylation and lysosomal genes, validating the clinical relevance of our findings.
Project description:Neurofibromatosis Type II is a genetic condition caused by loss of the NF2 gene, resulting in activation of the YAP/TAZ pathway and recurrent growth of benign tumors from Schwann cells, the glia of the peripheral nervous system. Unfortunately, no pharmacological therapy is currently available for NFII. Here, we undertake a genome-wide CRISPR/cas9 screen to search for synthetic-lethal genes that, when inhibited, cause death of NF2 mutant cells but not NF2 wildtype cells. We thereby identify ACSL3 and G6PD as two synthetic-lethal partners for NF2. We find that NF2 mutant Schwann cells are vulnerable to G6PD inhibition because they have low levels of ME1. G6PD and ME1 redundantly generate cytosolic NADPH needed by cells to fight oxidative stress. Lack of either one of the two is compatible with cell viability, but down-regulation of both leads to Schwann cell death. Since genetic deficiency for G6PD is tolerated in the human population, this raises the possibility that G6PD could be a pharmacological target for NFII.
Project description:Neurofibromatosis Type II is a genetic condition caused by loss of the NF2 gene, resulting in activation of the YAP/TAZ pathway and recurrent growth of benign tumors from Schwann cells, the glia of the peripheral nervous system. Unfortunately, no pharmacological therapy is currently available for NFII. Here, we undertake a genome-wide CRISPR/cas9 screen to search for synthetic-lethal genes that, when inhibited, cause death of NF2 mutant cells but not NF2 wildtype cells. We thereby identify ACSL3 and G6PD as two synthetic-lethal partners for NF2. We find that NF2 mutant Schwann cells are vulnerable to G6PD inhibition because they have low levels of ME1. G6PD and ME1 redundantly generate cytosolic NADPH needed by cells to fight oxidative stress. Lack of either one of the two is compatible with cell viability, but down-regulation of both leads to Schwann cell death. Since genetic deficiency for G6PD is tolerated in the human population, this raises the possibility that G6PD could be a pharmacological target for NFII.
Project description:Meningiomas are the most common primary brain tumors in adults. Although generally benign, a subset is of higher grade, recurs even after multiple surgeries, and frequently fatal. Around half of meningiomas harbor inactivating mutations in NF2. While low-grade NF2 mutant meningiomas harbor few additional mutations in addition to NF2 inactivation, high-grade NF2 mutant tumors frequently harbor a highly aberrant genome. We and others have previously shown that NF2 inactivation leads to YAP1 activation and that YAP1 acts as an oncogene in NF2 mutant meningiomas. Here, we show that high-grade NF2 mutant meningiomas downregulate YAP1 signaling, in part through upregulating the expression of the YAP1 competitor VGLL4 and the YAP1 upstream regulators FAT3/4. Overexpression of VGLL4 resulted in the downregulation of YAP activity and the growth inhibition of low-grade NF2 mutant meningioma cells. Our results have important implications for the efficacy of therapies targeting oncogenic YAP1 in high-grade NF2 mutant meningiomas.
Project description:To investigate the trancriptomic changes of endothelial cells (ECs) by Nf2/Merlin, Lewis Lung Carcinoma (LLC) tumor ECs from Ctrl and NF2 KO mice were sorted by FACS and single-cell RNA seq was performed.