Neuroprotective role of FOXA1 in Parkinson's disease: Involvements of NF1 transcription activation and MAPK signaling pathway inhibition.

Forkhead box A1 (FOXA1), a member of the forkhead family of transcription factors, plays a crucial role in the development of various organ systems and exhibits neuroprotective properties. This study aims to investigate the effect of FOXA1 on Parkinson's disease (PD) and unravel the underlying mechanism. Transcriptome analysis of PD was conducted using three GEO datasets to identify aberrantly expressed genes. A mouse model of PD was generated by injecting neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP), resulting in reduced FOXA1 expression. FOXA1 decline was also observed in 1-methyl-4-phenylpyridinium-treated SH-SY5Y cells. Artificial upregulation of FOXA1 improved motor abilities of mice according to rotarod and pole tests, and it mitigated tissue damage, cell loss, and neuronal damage in the mouse substantia nigra or in vitro. FOXA1 was found to bind to the neurofibromin 1 (NF1) promoter, thereby inducing its transcription and inactivating the mitogen-activated protein kinase (MAPK) signaling pathway. Further experimentation revealed that silencing NF1 in mice or SH-SY5Y cells counteracted the neuroprotective effects of FOXA1. In conclusion, this research suggests that FOXA1 activates NF1 transcription and inactivates the MAPK signaling pathway, ultimately ameliorating neuronal damage and motor disability in PD. The findings may offer novel ideas in the field of PD management.

The oncogenic role of NF1 in gallbladder cancer through regulation of YAP1 stability by direct interaction with YAP1.

BACKGROUND: Gallbladder cancer (GBC) is the most prevalent and invasive biliary tract malignancy. As a GTPase-activating protein, Neurofibromin 1 (NF1) is a tumor suppressor that negatively regulates the RAS signaling pathway, and its abnormality leads to neurofibromatosis type 1 (NF-1) disease. However, the role of NF1 playing in GBC and the underlying molecular mechanism has not been defined yet. METHODS: A combination of NOZ and EH-GB1 cell lines as well as nude mice, were utilized in this study. mRNA expression and protein levels of NF1 and YAP1 were evaluated by quantitative real-time PCR (qRT-PCR), western blot (WB), and immunohistochemistry (IHC). In vitro and in vivo assays were performed to explore the biological effects of NF1 in NOZ and EH-GB1 cells via siRNA or lv-shRNA mediated knockdown. Direct interaction between NF1 and YAP1 was detected by confocal microscopy and co-immunoprecipitation (Co-IP), and further confirmed by GST pull-down assay and isothermal titration calorimetry assay (ITC). The stability of proteins was measured by western blot (WB) in the presence of cycloheximide. RESULTS: This study showed that a higher level of NF1 and YAP1 was found in GBC samples than in normal tissues and associated with worse prognoses. The NF1 knockdown impaired the proliferation and migration of NOZ in vivo and in vitro by downregulating YAP1 expression. Moreover, NF1 co-localized with YAP1 in NOZ and EH-GB1 cells, and the WW domains of YAP1 specifically recognized the PPQY motif of NF1. The structural modeling also indicated the hydrophobic interactions between YAP1 and NF1. On the other hand, YAP1 knockdown also impaired the proliferation of NOZ in vitro, phenocopying the effects of NF1 knockdown. Overexpression of YAP1 can partially rescue the impaired proliferation in NF1 stably knockdown cells. In mechanism, NF1 interacted with YAP1 and increased the stability of YAP1 by preventing ubiquitination. CONCLUSIONS: Our findings discovered a novel oncogenic function of NF1 by directly interacting with YAP1 protein and stabilizing YAP1 to protect it from proteasome degradation in NOZ cells. NF1 may serve as a potential therapeutic target in GBC.

Co-occurrence of neurofibromatosis type 1 and pseudoachondroplasia - a first case report.

BACKGROUND: Neurofibromatosis type 1 and pseudoachondroplasia are both rare autosomal dominant disorders, caused by pathogenic mutations in NF1 and COMP genes, respectively. Both neurofibromin 1 and cartilage oligomeric matrix protein (COMP) play a role in the development of the skeleton. Carrying both germline mutations has not been previously reported; however, it can affect the developing phenotype. CASE PRESENTATION: The index patient, an 8-year-old female presented with several skeletal and dermatologic anomalies resembling the coexistence of multiple syndromes. Her mother had dermatologic symptoms characteristic for neurofibromatosis type 1, and her father presented with distinct skeletal anomalies. NGS-based analysis revealed a heterozygous pathogenic mutation in genes NF1 and COMP in the index patient. A previously unreported heterozygous variant was detected for the NF1 gene. The sequencing of the COMP gene revealed a previously reported, pathogenic heterozygous variant that is responsible for the development of the pseudoachondroplasia phenotype. CONCLUSIONS: Here, we present the case of a young female carrying pathogenic NF1 and COMP mutations, diagnosed with two distinct heritable disorders, neurofibromatosis type 1 and pseudoachondroplasia. The coincidence of two monogenic autosomal dominant disorders is rare and can pose a differential diagnostic challenge. To the best of our knowledge, this is the first reported co-occurrence of these syndromes.

CT of malignant peripheral nerve sheath tumor.

Malignant peripheral nerve sheath tumors are soft tissue sarcomas that typically arise from a neurofibroma. Patients with neurofibromatosis type 1 represent approximately half of the population diagnosed with these tumors. This autosomal-dominant genetic disorder is distinguished by loss-of-function mutations in the neurofibromin 1 gene, which ultimately promotes atypical cellular proliferation. These biologically aggressive tumors are associated with a poor prognosis as they are resistant to available therapies and have high rates of recurrence, progression, and mortality. In this article, we report the case of a 45-year-old male with a history of neurofibromatosis type 1 who was diagnosed with a malignant peripheral nerve sheath tumor. We focus on optimizing diagnosis and treatment through the application of radiological imaging modalities, including cinematic rendering.

Neurofibromatosis laríngea: a propósito de un caso / Laryngeal neurofibromatosis: a case report

Resumen El neurofibroma laríngeo es poco frecuente, representa menos del 0,1% de las neoplasias benignas de la laringe. Puede presentarse aislado, o más comúnmente asociado a neurofibromatosis tipo I. Se presenta el caso de un paciente varón de 40 años, ya diagnosticado de neurofibromatosis tipo I, que presenta masa supraglótica submucosa asintomática, diagnosticada como hallazgo casual en una intubación por una cirugía previa programada.

Abstract Laryngeal neurofibroma is rare, representing less than 0.1% of benign tumors of the larynx. It can occur in isolation or more commonly associated with type I neurofibromatosis. The case of a 40-year-old male patient, already diagnosed with type I neurofibromatosis, is presented with an asymptomatic submucosal supraglottic mass, diagnosed as a chance finding in intubation due to a previous scheduled surgery.

Expression of neurofibromin 1 in colorectal cancer and cetuximab resistance.

Neurofibromin 1 (NF1) is a tumor suppressor that has been previously reported to regulate RAS­MAPK signaling. The present study investigated the possible relationship between NF1 expression and anti­EGFR antibody (cetuximab) sensitivity in colorectal cancer cell lines. In addition, primary or metastatic colorectal cancer samples from patients treated with cetuximab were assessed for the association of cetuximab sensitivity. The quantities of the NF1 transcript, NF1­related pathway enrichment and NF1 mutation profile were measured and investigated using RNA sequencing and targeted DNA sequencing. Based on growth inhibition and colony formation assay results, cell lines were designated to be cetuximab­sensitive (NCI­H508 and Caco2) or cetuximab­resistant (KM12C and SM480). Western blotting revealed NF1 was highly expressed in cetuximab­sensitive cell lines whilst there was little expression in their cetuximab­resistant counterparts. Knocking down NF1 expression using small interfering RNA in the cetuximab­sensitive cell lines enhanced the phosphorylation of MEK and ERK according to western blotting. NF1 knockdown also reduced apoptosis, as observed by the decreased number of apoptotic bodies by DAPI nuclear staining and reduced cleavage of caspase and poly­(ADP ribose) polymerase. NF1 overexpression by transfection with GTPase­activating protein­related domain subunit rendered the cetuximab­resistant cell lines, KM12C and SW480, more susceptible to cetuximab­induced apoptosis. RNA sequencing of 111 RAS and BRAFV600 wild­type tumor samples collected from cetuximab­treated patients with metastatic colorectal cancer revealed that the pre­treatment NF1 expression levels were not associated with the cetuximab response. However, tumor samples obtained after cetuximab treatment displayed slightly lower NF1 transcript levels compared with those in the pre­treatment samples, suggesting that exposure to the anti­EGFR antibody may be associated with reduced NF1 expression levels. Next­generation sequencing revealed that the frequency of inactivating mutations in NF1 were rare (1.8%) in patients with colorectal cancer and were not associated with the protein expression levels of NF1 except for in a small number of cases (0.5%), where the biallelic inactivation of NF1 was observed. To conclude, the present study showed that modification of NF1 expression can affect sensitivity to cetuximab in colorectal cancer cell lines, though a limitation exists in terms of its potential application as a biomarker for RAS and BRAFV600 wild­type tumors.

Preimplantation genetic testing and prenatal diagnosis in a family with type Ⅰ neurofibromatosis / 中华围产医学杂志

We report the implantation genetic testing and prenatal diagnosis of a family with neurofibromatosis type I (NF1). High-throughput sequencing combined with multiplex ligation-dependent probe amplification was performed to identify the pathogenic mutation sites, then verified by Sanger sequencing. The pathogenic mutation of c.4172G>C in the NF1 gene was found in the proband and his mother. After sequencing and single nucleotide polymorphism (SNP) haplotyping of the mutation sites in the embryos by establishing the SNP-linked haplotype, a well-developed blastocyst, without pathogenic mutations, was transplanted, and 28 d later, the ultrasound confirmed that the patient was pregnant. Amniotic fluid samples of the fetus were obtained at 19 +3 weeks for karyotyping and detection of the gene mutation site, which found the fetus did not carry the maternal c.4172G>C mutation of NF1 gene or any copy number variants of clear clinical significance. The patient delivered a healthy term girl by cesarean section, and no significant abnormalities were found during the follow-up to 10 months of age.

Mechanism study of neurofibromin 1 in gallbladder cancer / 中华消化外科杂志

Objective:To investigate the mechanism of neurofibromin 1 (NF1) in gallbla-dder cancer.Methods:The experimental study was conducted. Human gallbladder cancer cell lines, including GBC-SD, NOZ, SGC996, EH-GB1, ZJU0428, human embryonic kidneys cell line 293T and human cervical cancer cell line HELA, were cultured. The recombinant plasmids (mRFP-YAP1 FL-FLAG and eGFP-MYC-NF1 2650?2750-HA) were constructed for co-immunoprecipitation experiment. The truncated Yes associated protein 1(YAP1) and NF1 recombinant proteins were purified in vitro. The interaction between NF1 and YAP1 in vitro or in vivo were verified by isothermal titration calori-metry (ITC) assay, GST pull-down experiment, co-immunoprecipitation, immunofluorescence, laser confocal microscopy, and the expression of NF1 protein in different gallbladder cancer cell lines was verified by Western blot experiments. Observation indicators: (1) interaction between NF1 and YAP1 in vitro; (2) interaction between NF1 and YAP1 in cells; (3) expression of NF1 protein in different human gallbladder cancer cell lines. The dissociation constants were exported from ITC 200 software and represented as Mean± SD. Count data were represented as absolute numbers. Results:(1) Interaction between NF1 and YAP1 in vitro. ① Results of ITC assay showed that there was interac-tion between PPQY and YAP1-WW1, between PPQY and YAP1 (Amino acid residues 162?275), and the dissociation constants between PPQY and YAP1-WW1, between PPQY and YAP1(Amino acid residues 162?275) were (0.42±0.06)mmol/L, (0.69±0.14)mmol/L, respectively. ② GST pull-down results indicated that the target protein His-Sumo-YAP1 WW1 was obviouly observed in protein lane of reaction system between GST-PPQY recombinant protein and His-Sumo-YAP1 WW1, relative to the reaction system between GST protein and His-Sumo-YAP1 WW1. The target protein His-Sumo-YAP1 WW2 was obviouly observed in protein lane of reaction system between GST-PPQY recombinant protein and His-Sumo-YAP1 WW2, relative to the reaction system between GST protein and His-Sumo-YAP1 WW2. (2) Interaction between NF1 and YAP1 in cells. ① Co-immunoprecipitation results indica-ted that NF1 protein was observed in cell lysis solution which was incubated by FLAG gel beads and cotransfected with mRFP-YAP1 FL-FLAG and eGFP-MYC-NF1 2650?2750-HA. ② Immuno-fluorescence and laser confocal microscopy results indicated that YAP1 and NF1 with obvious fluorescence were co-localized in the cytoplasm of human gallbladder cancer NOZ cells. However, YAP1 with obvious fluorescence was localized in the nucleus of human gallbladder SGC996 cells and NF1 showed weak fluorescence. (3) Expression of NF1 protein in different human gallbladder cancer cell lines. Western blot results showed that with the expression level of NF1 protein in HELA cell line as the standard, the relative expression levels of NF1 protein in EH-GB1, GBC-SD, NOZ, SGC996, ZJU0428 cell lines were 1.28, 0, 1.01, 0, 0, respectively. Conclusion:NF1 affects the gallbladder cancer by directly acting on YAP1 protein.

3D disorganization and rearrangement of genome provide insights into pathogenesis of NAFLD by integrated Hi-C, Nanopore, and RNA sequencing.

The three-dimensional (3D) conformation of chromatin is integral to the precise regulation of gene expression. The 3D genome and genomic variations in non-alcoholic fatty liver disease (NAFLD) are largely unknown, despite their key roles in cellular function and physiological processes. High-throughput chromosome conformation capture (Hi-C), Nanopore sequencing, and RNA-sequencing (RNA-seq) assays were performed on the liver of normal and NAFLD mice. A high-resolution 3D chromatin interaction map was generated to examine different 3D genome hierarchies including A/B compartments, topologically associated domains (TADs), and chromatin loops by Hi-C, and whole genome sequencing identifying structural variations (SVs) and copy number variations (CNVs) by Nanopore sequencing. We identified variations in thousands of regions across the genome with respect to 3D chromatin organization and genomic rearrangements, between normal and NAFLD mice, and revealed gene dysregulation frequently accompanied by these variations. Candidate target genes were identified in NAFLD, impacted by genetic rearrangements and spatial organization disruption. Our data provide a high-resolution 3D genome interaction resource for NAFLD investigations, revealed the relationship among genetic rearrangements, spatial organization disruption, and gene regulation, and identified candidate genes associated with these variations implicated in the pathogenesis of NAFLD. The newly findings offer insights into novel mechanisms of NAFLD pathogenesis and can provide a new conceptual framework for NAFLD therapy.

Distinct progenitor behavior underlying neocortical gliogenesis related to tumorigenesis.

Radial glial progenitors (RGPs) give rise to the vast majority of neurons and glia in the neocortex. Although RGP behavior and progressive generation of neocortical neurons have been delineated, the exact process of neocortical gliogenesis remains elusive. Here, we report the precise progenitor behavior and gliogenesis program at single-cell resolution in the mouse neocortex. Fractions of dorsal RGPs transition from neurogenesis to gliogenesis progressively, producing astrocytes, oligodendrocytes, or both in well-defined propensities of ∼60%, 15%, and 25%, respectively, by fate-restricted "intermediate" precursor cells (IPCs). Although the total number of IPCs generated by individual RGPs appears stochastic, the output of individual IPCs exhibit clear patterns in number and subtype and form discrete local subclusters. Clonal loss of tumor suppressor Neurofibromatosis type 1 leads to excessive production of glia selectively, especially oligodendrocyte precursor cells. These results quantitatively delineate the cellular program of neocortical gliogenesis and suggest the cellular and lineage origin of primary brain tumor.

Social Behavioral Deficits with Loss of Neurofibromin Emerge from Peripheral Chemosensory Neuron Dysfunction.

Neurofibromatosis type 1 (NF1) is a neurodevelopmental disorder associated with social and communicative disabilities. The cellular and circuit mechanisms by which loss of neurofibromin 1 (Nf1) results in social deficits are unknown. Here, we identify social behavioral dysregulation with Nf1 loss in Drosophila. These deficits map to primary dysfunction of a group of peripheral sensory neurons. Nf1 regulation of Ras signaling in adult ppk23+ chemosensory cells is required for normal social behaviors in flies. Loss of Nf1 attenuates ppk23+ neuronal activity in response to pheromones, and circuit-specific manipulation of Nf1 expression or neuronal activity in ppk23+ neurons rescues social deficits. This disrupted sensory processing gives rise to persistent changes in behavior beyond the social interaction, indicating a sustained effect of an acute sensory misperception. Together our data identify a specific circuit mechanism through which Nf1 regulates social behaviors and suggest social deficits in NF1 arise from propagation of sensory misinformation.

New Model Systems and the Development of Targeted Therapies for the Treatment of Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheath Tumors.

Neurofibromatosis Type 1 (NF1) is a common genetic disorder and cancer predisposition syndrome (1:3000 births) caused by mutations in the tumor suppressor gene NF1. NF1 encodes neurofibromin, a negative regulator of the Ras signaling pathway. Individuals with NF1 often develop benign tumors of the peripheral nervous system (neurofibromas), originating from the Schwann cell linage, some of which progress further to malignant peripheral nerve sheath tumors (MPNSTs). Treatment options for neurofibromas and MPNSTs are extremely limited, relying largely on surgical resection and cytotoxic chemotherapy. Identification of novel therapeutic targets in both benign neurofibromas and MPNSTs is critical for improved patient outcomes and quality of life. Recent clinical trials conducted in patients with NF1 for the treatment of symptomatic plexiform neurofibromas using inhibitors of the mitogen-activated protein kinase (MEK) have shown very promising results. However, MEK inhibitors do not work in all patients and have significant side effects. In addition, preliminary evidence suggests single agent use of MEK inhibitors for MPNST treatment will fail. Here, we describe the preclinical efforts that led to the identification of MEK inhibitors as promising therapeutics for the treatment of NF1-related neoplasia and possible reasons they lack single agent efficacy in the treatment of MPNSTs. In addition, we describe work to find targets other than MEK for treatment of MPNST. These have come from studies of RAS biochemistry, in vitro drug screening, forward genetic screens for Schwann cell tumors, and synthetic lethal screens in cells with oncogenic RAS gene mutations. Lastly, we discuss new approaches to exploit drug screening and synthetic lethality with NF1 loss of function mutations in human Schwann cells using CRISPR/Cas9 technology.

MicroRNA-103a-3p potentiates chemoresistance to cisplatin in non-small cell lung carcinoma by targeting neurofibromatosis 1.

Lung cancer remains the leading cause of cancer-associated mortality worldwide, and non-small-cell lung cancer (NSCLC) contributes to ~80% of these deaths. However, both primary and acquired cisplatin resistance frequently occurs within the disease and represents a huge clinical treatment problem. The underlying molecular mechanisms are not yet completely understood, but in recent years, microRNAs (miR) have been reported to play vital roles in the development of lung cancer and chemoresistance. In the present study, it was revealed that there were increased expression levels of miR-103a-3p in both NSCLC cell lines and human NSCLC samples that exhibited resistance to cisplatin. The results also revealed that the inhibition of miR-103a-3p in A549/cisplatin cells significantly sensitized these cells to cisplatin, while inhibition of miR-103a-3p expression inhibited tumor growth and enhanced the function of cisplatin in a xenograft animal model. Furthermore, the present study demonstrated that miR-103a-3p regulates cisplatin resistance by targeting neurofibromatosis 1 (NF1) via activating ERK signaling in vitro and in vivo. In conclusion, NF1 was identified as a special miR-103a-3p target in the present study, and it was revealed that targeting NF1 via miR-103a-3p may help reverse chemoresistance and provide a biomarker to cisplatin responsiveness in NSCLC.

Clinical significance of the molecular heterogeneity of gastrointestinal stromal tumors and related research: A systematic review.

Gastrointestinal stromal tumors (GISTs) are the most commonly observed mesenchymal tumors of the digestive tract, and they originate from the interstitial cells of Cajal. GISTs can be divided into KIT/PDGFRA­mutant GISTs and wild­type GISTs based on the presence or absence of KIT/PDGFRA mutations. Wild­type GISTs can be divided into succinate dehydrogenase complex (SDH)­deficient GISTs and non­SDH­deficient GISTs. Downstream signaling pathways activated by these mutations serve a pivotal role in the development of GISTs and are associated with the biological behavior, including risk stratification, clinical prognosis and drug resistance. Accurate medical care requires accurate molecular diagnosis, which in turn prolongs the survival of patients with GISTs and makes GIST a chronic disease. At present, there is a lack of effective treatment for imatinib/sunitinib/regorafenib resistant patients and KIT/PDGFRA­WT GISTs, which is undoubtedly a major challenge for future research. The present review summarizes the molecular pathogenesis of GISTs and the progress of related research.

Clinical characteristics and mutation Spectrum of NF1 in 12 Chinese families with orbital/periorbital plexiform Neurofibromatosis type 1.

BACKGROUND: Orbital/periorbital plexiform neurofibroma (OPPN) can compromise physical appearance and visual function. However, the clinical characteristics and NF1 mutation landscape in patients with heritable OPPN have not been reported. METHODS: The medical charts of 26 Chinese patients with OPPN from 12 families were reviewed. Mutation analysis of the entire coding region and flanking splice sites of the NF1 gene was performed using next-generation sequencing (NGS). Novel NF1 mutations were confirmed by Sanger sequencing. RESULTS: Compared to the parental generation, a significantly larger proportion of OPPN patients in the successive generation presented with earlier onset (p = 0.001), amblyopia (p = 0.034), motility disorders (p = 0.009) and bony orbital expansion (p = 0.019). Six novel NF1 mutations were identified in 11 (91.67%) families, including 6 (42.9%) single-base substitutions, 4 (28.5%) splicing mutations, 3 (21.4%) frameshift deletions, and 1 (7.14%) intron mutation. CONCLUSIONS: The successive generation of OPPN patients presented with earlier onset and exhibited more severe ocular signs than did their parents or grandparents. Special attention should be paid to successive generations of OPPN patients. Considering that 6 mutations were novel, comprehensive NF1 mutation analysis is required or necessary or proposed for genetic counselling.

Neurofibromin 1 expression is negatively correlated with malignancy and prognosis of epithelial ovarian cancer.

Epithelial ovarian cancer ranks as the 5th most deadly female cancer. However, few effective biomarkers have been identified for clinical application. Thus, it is critical to identify differentially expressed genes in epithelial ovarian cancer patient samples. Our work has focused on a tumor suppressor gene Neurofibromin 1 and its role in epithelial ovarian cancer pathology. We examined 124 samples of benign ovarian tissues, borderline ovarian tissues, and epithelial ovarian cancer tissues for NF1 expression by immunohistochemistry and further validated our results using RT-PCR and Western blot. We next analyzed the follow-up information with pathological features using Kaplan-Meier univariate survival analysis and Cox regression multivariate analysis. First, our results show that the mRNA level and protein level of NF1 are significantly decreased in epithelial ovarian cancer patients. Second, NF1 expression is negatively associated with 5-year overall survival, lymph node metastasis, and tumor size. Furthermore, our data also suggests that NF1 expression is a protective factor for epithelial ovarian cancer prognosis. NF1 is negatively regulated in EOC patients and low expression of NF1 is associated with lymph node metastasis. More importantly, patients that have lost NF1 showed poorer prognosis and five-year overall survival.

Conditional Inactivation of Nf1 and Pten in Schwann Cells Results in Abnormal Neuromuscular Junction Maturation.

The neuromuscular junction (NMJ) consists of three components, namely presynaptic motor neurons, postsynaptic muscle fibers and perisynaptic Schwann cells (PSCs). The role of Schwann cells (SCs) in regulating NMJ structural and functional development remains unclear. In this study, mice with conditional inactivation of neurofibromin 1 (Nf1) and phosphatase and tensin homolog (Pten), specifically in SCs, resulted in delayed NMJ maturation that led to delayed muscle growth, recapitulating the muscular dystrophy condition observed in human neurofibromatosis type I syndrome (NF1) patients. Expression levels of NMJ development related molecules such as cholinergic receptor, nicotinic, alpha polypeptide 1 (Chrna1), agrin (Agrn), dystrophin, muscular dystrophy (Dmd), laminin, beta 2 (Lamb2) and dystroglycan 1 (Dag1) were also downregulated. To further explore the molecular alterations in these SCs, NF1- and PTEN-related pathways were analyzed in mutant sciatic nerves. As expected, hyperactive RAS/PI3K/AKT/mTOR signaling pathways were identified, suggesting the importance of these pathways for NMJ development, and subsequent muscle maturation.

Exploiting mitochondrial and metabolic homeostasis as a vulnerability in NF1 deficient cells.

Neurofibromatosis type 1 is a disease caused by mutation of neurofibromin 1 (NF1), loss of which results in hyperactive Ras signaling and a concomitant increase in cell proliferation and survival. Patients with neurofibromatosis type 1 frequently develop tumors such as plexiform neurofibromas and malignant peripheral nerve sheath tumors. Mutation of NF1 or loss of the NF1 protein is also observed in glioblastoma, lung adenocarcinoma, and ovarian cancer among other sporadic cancers. A therapy that selectively targets NF1 deficient tumors would substantially advance our ability to treat these malignancies. To address the need for these therapeutics, we developed and conducted a synthetic lethality screen to discover molecules that target yeast lacking the homolog of NF1, IRA2. One of the lead candidates that was observed to be synthetic lethal with ira2Δ yeast is Y100. Here, we describe the mechanisms by which Y100 targets ira2Δ yeast and NF1-deficient tumor cells. Y100 treatment disrupted proteostasis, metabolic homeostasis, and induced the formation of mitochondrial superoxide in NF1-deficient cancer cells. Previous studies also indicate that NF1/Ras-dysregulated tumors may be sensitive to modulators of oxidative and ER stress. We hypothesize that the use of Y100 and molecules with related mechanisms of action represent a feasible therapeutic strategy for targeting NF1 deficient cells.

Molecular characterization and pathogenesis of gastrointestinal stromal tumor.

Most gastrointestinal stromal tumors (GISTs) harbor activating mutations in the receptor tyrosine kinase gene KIT or platelet-derived growth factor receptor alpha (PDGFRA), and the resultant activation of downstream signals plays a pivotal role in the development of GISTs. The sites of the tyrosine kinase gene mutations are associated with the biological behavior of GISTs, including risk category, clinical outcome and drug response. Mutations in RAS signaling pathway genes, including KRAS and BRAF, have also been reported in KIT/PDGFRA wild-type GISTs, though they are rare. Neurofibromin 1 (NF1) is a tumor suppressor gene mutated in neurofibromatosis type 1. Patients with NF1 mutations are at high risk of developing GISTs. Recent findings suggest that altered expression or mutation of members of succinate dehydrogenase (SDH) heterotetramer are causally associated with GIST development through induction of aberrant DNA methylation. At present, GISTs with no alterations in KIT, PDGFRA, RAS signaling genes or SDH family genes are referred to as true wild-type GISTs. KIT and PDGFRA mutations are thought as the earliest events in GIST development, and subsequent accumulation of chromosomal aberrations and other molecular alterations are required for malignant progression. In addition, recent studies have shown that epigenetic alterations and noncoding RNAs also play key roles in the pathogenesis of GISTs.

A Novel c.6766_6767insAA Mutation in the Neurofibromin Gene in a Patient with Neurofibromatosis Type 1-Associated Glioblastoma / 대한소아신경학회지

Neurofibromatosis type 1 (NF-1) is an autosomal dominant neurocutaneous syndrome caused by mutations in the neurofibromin gene. NF-1 patients have a high risk of tumors, and optic glioma is the most commonly observed central nervous system tumor in these patients. However, glioblastoma is extremely rare in pediatric NF-1 patients. Here we report the discovery of a novel heterozygous c.6766_6767insAA (p.Ser2256Lysfs*4), pathogenic mutation in the neurofibromin gene in a 17-year-old boy with NF-1-associated glioblastoma.