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:Pleural mesothelioma (PM) is one of the deadliest cancers, with limited therapeutic options due to its therapeutically intractable genome, which is characterized by the functional inactivation of tumor suppressor genes (TSGs) and high tumor heterogeneity, including diverse metabolic adaptations. However, the molecular mechanisms underlying these metabolic alterations remain poorly understood, particularly how TSG inactivation rewires tumor metabolism to drive tumorigenesis and create metabolic dependencies. Through integrated multi-omics analysis, we identify for the first time that NF2 loss of function defines a distinct PM subtype characterized by enhanced de novo pyrimidine synthesis, which NF2-deficient PM cells are critically dependent on for sustained proliferation in vitro and in vivo. Mechanistically, NF2 loss activates YAP, a downstream proto-oncogenic transcriptional coactivator in the Hippo signalling pathway, which in turn upregulates CAD and DHODH, key enzymes in the de novo pyrimidine biosynthesis pathway. Our findings provide novel insights into metabolic reprogramming in PM, revealing de novo pyrimidine synthesis as a synthetic lethal vulnerability in NF2-deficient tumors. This work highlights a potential therapeutic strategy for targeting NF2-deficient mesothelioma through metabolic intervention.
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:We previously generated an orthotopic, NF2-deficient meningioma model using the luciferase-expressing Ben-Men-1 cell line established from a sporadic tumor and identified the multi-kinase inhibitor brigatinib and the mTOR kinase inhibitor INK128 to potently impede tumor growth. Here, we describe generation of the telomerase-immortalized AG-NF2-Men cell line from a grade-1 meningioma of an NF2-related schwannomatosis (NF2-SWN) patient. We showed that like Ben-Men-1 cells, AG-NF2-Men cells were NF2-null, expressed several NF2-regulated receptor tyrosine kinases, and responded to their cognate ligands. We also found that brigatinib and INK128 alone inhibited AG-NF2-Men cell proliferation at IC50 values similar to those in Ben-Men-1 cells. Combining brigatinib with INK128 exhibited growth-inhibitory synergy. Mechanistically, the combination not only completely abrogated p-AKT(S473) and its downstream signaling compared to either drug alone but also prevented INK128-mediated re-phosphorylation of AKT on T308. Also, the combination more-effectively blocked ligand-mediated phosphorylation of EGFR, ErbB3, and IGF-1R and elicited major changes in the expression of genes including the upstream regulators of several signaling networks important for meningioma growth. Further, we generated luciferase-expressing AG-NF2-Men cells that readily grew as intracranial xenografts. Importantly, combining brigatinib with INK128 enhanced tumor regression in both the orthotopic AG-NF2-Men and Ben-Men-1 xenograft models. As the first NF2-SWN-related meningioma cell line, AG-NF2-Men is a unique reagent for investigating meningioma biology and therapeutics. A clinical trial to evaluate the combination of brigatinib with an mTOR inhibitor in NF2-deficient meningiomas is warranted.
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:Pleural mesothelioma (PM) is one of the deadliest cancers, with limited therapeutic options due to its therapeutically intractable genome, which is characterized by the functional inactivation of tumor suppressor genes (TSGs) and high tumor heterogeneity, including diverse metabolic adaptations. However, the molecular mechanisms underlying these metabolic alterations remain poorly understood, particularly how TSG inactivation rewires tumor metabolism to drive tumorigenesis and create metabolic dependencies. Through integrated multi-omics analysis, we identify for the first time that NF2 loss of function defines a distinct PM subtype characterized by enhanced de novo pyrimidine synthesis, which NF2-deficient PM cells are critically dependent on for sustained proliferation in vitro and in vivo. Mechanistically, NF2 loss activates YAP, a downstream proto-oncogenic transcriptional coactivator in the Hippo signalling pathway, which in turn upregulates CAD and DHODH, key enzymes in the de novo pyrimidine biosynthesis pathway. Our findings provide novel insights into metabolic reprogramming in PM, revealing de novo pyrimidine synthesis as a synthetic lethal vulnerability in NF2-deficient tumors. This work highlights a potential therapeutic strategy for targeting NF2-deficient mesothelioma through metabolic intervention.
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.