The RAS/MAPK pathway is an emerging targeted pathway across a spectrum of both adult and pediatric cancers. Typically, this is associated with a single, well-characterized point mutation in an oncogene. Hypermutant tumors that harbor many somatic mutations may obscure the interpretation of such targetable genomic events. We find that replication repair-deficient (RRD) cancers, which are universally hypermutant and affect children born with RRD cancer predisposition, are enriched for RAS/MAPK mutations (P = 10-8). These mutations are not random, exist in subclones, and increase in allelic frequency over time. The RAS/MAPK pathway is activated both transcriptionally and at the protein level in patient-derived RRD tumors, and these tumors responded to MEK inhibition in vitro and in vivo. Treatment of patients with RAS/MAPK hypermutant gliomas reveals durable responses to MEK inhibition. Our observations suggest that hypermutant tumors may be addicted to oncogenic pathways, resulting in favorable response to targeted therapies. SIGNIFICANCE: Tumors harboring a single RAS/MAPK driver mutation are targeted individually for therapeutic purposes. We find that in RRD hypermutant cancers, mutations in the RAS/MAPK pathway are enriched, highly expressed, and result in sensitivity to MEK inhibitors. Targeting an oncogenic pathway may provide therapeutic options for these hypermutant polyclonal cancers.This article is highlighted in the In This Issue feature, p. 1307.

• MeSH
• celosvětové zdraví MeSH
• dítě MeSH
• dospělí MeSH
• genetická predispozice k nemoci * MeSH
• gliom farmakoterapie   genetika   MeSH
• inhibitory proteinkinas terapeutické užití   MeSH
• kolorektální nádory farmakoterapie   genetika   MeSH
• lidé MeSH
• mitogenem aktivované proteinkinasy kinas genetika   MeSH
• mutace MeSH
• myši inbrední NOD MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádory mozku farmakoterapie   genetika   MeSH
• protinádorové látky terapeutické užití   MeSH
• zvířata MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Cardio-facio-cutaneous (CFC) and Costello syndrome (CS) are congenital disorders with a significant clinical overlap. The recent discovery of heterozygous mutations in genes encoding components of the RAS-RAF-MAPK pathway in both CFC and CS suggested a similar underlying pathogenesis of these two disorders. While CFC is heterogeneous with mutations in BRAF, MAP2K1, MAP2K2 and KRAS, HRAS alterations are almost exclusively associated with CS. We carried out a comprehensive mutation analysis in 51 CFC-affected patients and 31 individuals with CS. Twelve different BRAF alterations were found in twenty-four patients with CFC (47.0%), two MAP2K1 mutations in five (9.8%) and two MAP2K2 sequence variations in three CFC-affected individuals (5.9%), whereas three patients had a KRAS alteration (5.9%). We identified four different missense mutations of HRAS in twenty-eight cases with CS (90.3%), while KRAS mutations were detected in two infants with a phenotype meeting criteria for CS (6.5%). In 14 informative families, we traced the parental origin of HRAS alterations and demonstrated inheritance of the mutated allele exclusively from the father, further confirming a paternal bias in the parental origin of HRAS mutations in CS. Careful clinical evaluation of patients with BRAF and MAP2K1/2 alterations revealed the presence of slight phenotypic differences regarding craniofacial features in MAP2K1- and MAP2K2-mutation positive individuals, suggesting possible genotype-phenotype correlations.

• MeSH
• dítě MeSH
• dospělí MeSH
• faciální stigmatizace * MeSH
• fenotyp MeSH
• kožní abnormality * genetika   MeSH
• lidé MeSH
• MAP kinasa-kinasa 1 genetika   MeSH
• MAP kinasa-kinasa 2 genetika   MeSH
• mentální retardace MeSH
• mnohočetné abnormality * genetika   MeSH
• mutace * MeSH
• mutační analýza DNA MeSH
• protoonkogenní proteiny B-raf genetika   MeSH
• protoonkogenní proteiny genetika   MeSH
• ras proteiny genetika   MeSH
• syndrom MeSH
• vrozené srdeční vady * genetika   MeSH
• vývojové poruchy u dětí MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

AIM: Valproic acid (VPA) is a widely-used anticonvulsant and mood-stabilizing agent. VPA is also known to inhibit histone deacetylases (HDACs) affecting the expression of numerous genes. METHODS: In the present study, we examined the effect of VPA on the extracellular signal-related kinase (ERK, p42/p44) pathway (Ras-Raf-MEK-ERK) belonging to the mitogen-activated protein kinases (MAPKs) pathways in primary human hepatocytes. In the liver, the pathway is associated with progression of hepatocellular carcinoma. RESULTS: We found that VPA in a therapeutically relevant concentration (500 μM) activates the ERK pathway, as indicated by increased ERK Thr202/Tyr204 phosphorylation. Interestingly, a prototype HDAC inhibitor, trichostatin A, also activated ERK phosphorylation in primary human hepatocytes. These data suggest that HDAC inhibition might be the primary stimulus for ERK pathway activation in primary human hepatocytes. Notably, U0126, a MEK1 inhibitor, was ineffective in inhibiting ERK pathway activation, likely due to its metabolic deactivation in metabolically competent primary human hepatocytes. CONCLUSION: We conclude that VPA activates the ERK pathway in primary human hepatocytes.

• MeSH
• fosforylace účinky léků   MeSH
• hepatocyty účinky léků   metabolismus   MeSH
• inhibitory histondeacetylas farmakologie   MeSH
• kultivované buňky MeSH
• kyselina valproová farmakologie   MeSH
• kyseliny hydroxamové farmakologie   MeSH
• lidé MeSH
• MAP kinasový signální systém účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The eIF4F translation initiation complex plays a critical role in melanoma resistance to clinical BRAF and MEK inhibitors. In this study, we uncover a function of eIF4F in the negative regulation of the rat sarcoma (RAS)/rapidly accelerated fibrosarcoma (RAF)/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) signaling pathway. We demonstrate that eIF4F is essential for controlling ERK signaling intensity in treatment-naïve melanoma cells harboring BRAF or NRAS mutations. Specifically, the dual-specificity phosphatase DUSP6/MKP3, which acts as a negative feedback regulator of ERK activity, requires continuous production in an eIF4F-dependent manner to limit excessive ERK signaling driven by oncogenic RAF/RAS mutations. Treatment with small-molecule eIF4F inhibitors disrupts the negative feedback control of MAPK signaling, leading to ERK hyperactivation and EGR1 overexpression in melanoma cells in vitro and in vivo. Furthermore, our quantitative analyses reveal a high spare signaling capacity in the ERK pathway, suggesting that eIF4F-dependent feedback keeps the majority of ERK molecules inactive under normal conditions. Overall, our findings highlight the crucial role of eIF4F in regulating ERK signaling flux and suggest that pharmacological eIF4F inhibitors can disrupt the negative feedback control of MAPK activity in melanomas with BRAF and NRAS activating mutations.

• MeSH
• eukaryotický iniciační faktor 4F * metabolismus   genetika   MeSH
• extracelulárním signálem regulované MAP kinasy metabolismus   MeSH
• fosfatasa 6 s dvojí specificitou metabolismus   genetika   MeSH
• GTP-fosfohydrolasy * metabolismus   genetika   MeSH
• lidé MeSH
• MAP kinasový signální systém * genetika   MeSH
• melanom * genetika   metabolismus   patologie   MeSH
• membránové proteiny * metabolismus   genetika   MeSH
• mutace * MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• protoonkogenní proteiny B-Raf * genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Sinonasal mucosal melanoma is a rare tumor arising within the nasal cavity, paranasal sinuses, or nasopharynx (sinonasal tract). This study evaluated 90 cases diagnosed in 29 males and 61 females with median age 68 years. Most tumors involved the nasal cavity and had an epithelioid morphology. Spectrum of research techniques used in this analysis includes targeted-DNA and -RNA next-generation sequencing, Sanger sequencing, fluorescence in situ hybridization and immunohistochemistry. Sinonasal melanomas were commonly driven by RAS (38/90, 42%), especially NRAS (n = 36) mutations and rarely (4/90, 4%) displayed BRAF pathogenic variants. BRAF/RAS mutants were more frequent among paranasal sinuses (10/14, 71%) than nasal (26/64, 41%) tumors. BRAF/RAS-wild type tumors occasionally harbored alterations of the key components and regulators of Ras-MAPK signaling pathway: NF1 mutations (1/17, 6%) or NF1 locus deletions (1/25, 4%), SPRED1 (3/25, 12%), PIK3CA (3/50, 6%), PTEN (4/50, 8%) and mTOR (1/50, 2%) mutations. These mutations often occurred in a mutually exclusive manner. In several tumors some of which were NRAS mutants, TP53 was deleted (6/48, 13%) and/or mutated (5/90, 6%). Variable nuclear accumulation of TP53, mirrored by elevated nuclear MDM2 expression was seen in >50% of cases. Furthermore, sinonasal melanomas (n = 7) including RAS/BRAF-wild type tumors (n = 5) harbored alterations of the key components and regulators of canonical WNT-pathway: APC (4/90, 4%), CTNNB1 (3/90, 3%) and AMER1 (1/90, 1%). Both, TERT promoter mutations (5/53, 9%) and fusions (2/40, 5%) were identified. The latter occurred in BRAF/RAS-wild type tumors. No oncogenic fusion gene transcripts previously reported in cutaneous melanomas were detected. Eight tumors including 7 BRAF/RAS-wild type cases expressed ADCK4::NUMBL cis-fusion transcripts. In summary, this study documented mutational activation of NRAS and other key components and regulators of Ras-MAPK signaling pathway such as SPRED1 in a majority of sinonasal melanomas.

• MeSH
• fosfatidylinositol-3-kinasy třídy I genetika   MeSH
• hybridizace in situ fluorescenční MeSH
• lidé MeSH
• melanom * genetika   patologie   MeSH
• molekulární biologie MeSH
• mutace MeSH
• mutační analýza DNA MeSH
• nádory vedlejších dutin nosních * genetika   patologie   MeSH
• paranazální dutiny * patologie   MeSH
• protoonkogenní proteiny B-raf genetika   MeSH
• RNA MeSH
• senioři MeSH
• signální transdukce MeSH
• TOR serin-threoninkinasy genetika   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

T-2 toxin, a major compound of trichothecenes, inhibits protein synthesis and induces inflammation and cell apoptosis through the activation of MAPK pathway. The JAK/STAT pathway has recently been shown to be downstream targets of trichothecenes. However, whether there is any crosstalk between JNK and JAK/STAT pathways in trichothecene toxicity has not been studied. In the present study, we explored this potential in RAW264.7 cells treated with T-2 toxin. Our results revealed a crosstalk between JNK1 and STAT3 after T-2 toxin treatment, which was mediated by K-Ras. T-2 toxin treatment resulted in rapid phosphorylation, and more importantly, JNK1-STAT3 signaling pathway was shown to maintain the normal function of the mitochondria and to inhibit T-2 toxin-induced apoptosis. Therefore, this pathway was considered to be a potential cell survival pathway. Breakdown and degranulation of ribosomes in the rough endoplasmic reticulum and swelling of mitochondria were clearly visible after the cells had been incubated with T-2 toxin for 12h. Our data suggest that T-2 toxin had a Janus face: it induced both apoptotic and cell survival pathways. These results suggest that the crosstalk and the balance between MAPK and JAK/STAT pathway might be involved in T-2 toxin-induced apoptosis in RAW264.7 cells.

• MeSH
• anthraceny farmakologie   MeSH
• apoptóza účinky léků   MeSH
• biologické modely MeSH
• buněčné linie MeSH
• cytokiny genetika   metabolismus   MeSH
• fluorescenční protilátková technika MeSH
• fosforylace účinky léků   MeSH
• Janus kinasy metabolismus   MeSH
• kinetika MeSH
• makrofágy cytologie   účinky léků   metabolismus   ultrastruktura   MeSH
• mitochondrie účinky léků   metabolismus   ultrastruktura   MeSH
• mitogenem aktivovaná proteinkinasa 8 metabolismus   MeSH
• myši MeSH
• ras proteiny metabolismus   MeSH
• regulace genové exprese účinky léků   MeSH
• ribozomy účinky léků   metabolismus   ultrastruktura   MeSH
• signální transdukce * účinky léků   MeSH
• T-2 toxin farmakologie   MeSH
• transkripční faktor STAT3 metabolismus   MeSH
• viabilita buněk účinky léků   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

RASopatie je skupina syndromů, které jsou způsobeny zárodečnými mutacemi v genech, které kódují složky signální dráhy RAS/MAPK. Tato cesta je klíčem k regulaci buněk, jejich proliferaci, diferenciaci a přežití. Pro velkou heterogenitu fenotypových projevů převládala v posledních letech klinická diagnóza RASopatií po narození, prenatální detekce těchto syndromů je ale možná. Hlavní úlohu při stanovení fetální diagnózy hraje ultrazvukové vyšetření plodu během screeningových testů. Mezi typické společné znaky a indikační kritéria pro molekulární sekvenování na RASopatie patří patologická hodnota šíjového projasnění, rozšíření lymfatických jugulárních váčků, vývoj cystického hygromu, výpotky nebo fetální hydrops, polyhydramnion, vrozené srdeční vady a patologie ledvin. Při patologickém výsledku prenatálního screeningu je, i při normálních výsledcích karyotypu, vhodné další ultrazvukové a genetické došetření plodu.

RASopathy is a group of syndromes that are caused by germline mutations in genes that encode components of the RAS/MAPK signaling pathway. This pathway is key for cell regulation, proliferation, differentiation, and survival. For the great heterogeneity of phenotypic manifestations, the clinical diagnosis prevailed in the past years after birth, but the detection of these syndromes is possible also prenatally. Ultrasound examination of the fetus during screening tests plays a major role. Typical common features and indication criteria for RASopathy sequencing include pathological nuchal translucency measurement, lymphatic jugular sacs enlargement, development of cystic hygroma, effusions or fetal hydrops, polyhydramnios, congenital heart disease, and renal pathology. In pathological prenatal screening, even with normal karyotype results, additional ultrasound and genetic fetal examination are appropriate.

• Klíčová slova
• RASopatie,
• MeSH
• lidé MeSH
• měření nuchální translucence metody   MeSH
• Noonanové syndrom * diagnóza   MeSH
• prenatální diagnóza * metody   MeSH
• těhotenství MeSH
• Check Tag
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• přehledy MeSH

Ionotropní glutamátové receptory NMDA typu hrají podstatnou roli v procesu synaptické plasticity, která je základem učení a paměti. Změna spojení mezi neurony je důsledkem působení jednak lokálních faktorů v synapsi a jednak celkových faktorů, které zahrnují aktivaci proteinkináz a přenos signálu do buněčného jádra, kde proteinkinázy fosforylují konstitutivně exprimované transkripční faktory, které řídí expresi tzv. genů časné odpovědi, z nichž některé jsou samy transkripční faktory a kontrolují expresi dalších cílových genů. Článek prezentuje dosud známé poznatky o mechanizmu přenosu signálu od NMDA receptoru k indukci modelového genu časné odpovědi c-fos, jehož exprese je pod kontrolou několika konstitutivních faktorů, mezi jinými CREB (cAMP-response element binding protein), který musí být fosforylován na kritickém Ser133, aby aktivoval transkripci. Rychlým důsledkem aktivace NMDA receptoru je translokace komplexu Ca2+-kalmodulin do jádra a aktivace Ca2+/kalmodulin dependentní kinázy IV. S pomalejší kinetikou dochází k aktivaci Ras-MAPK (mitogen-activated protein kinase) kinázové kaskády, která je zřejmě v signalizaci do jádra neuronu nejdůležitější a přes jiné specifické signální molekuly integruje i signalizaci využívající Ca2+ nebo cyklický AMP jako druhého posla.

Ionotropic NMDA glutamate receptors play a central role in the process of synaptic plasticity underlying learning and memory. Alteration of neuronal connections results from local effects in the target synapse as well as from the whole-cell factors that encompass activation of protein kinases and signal transduction to the cell nucleus, where the kinases phosphorylate constitutively expressed transcription factors controlling expression of a set of immediate-early genes; some of them, in turn, are themselves transcription factors and regulate expression of further target genes. The article presents some of knowledge accumulated to date, on the mechanism of signal transduction from NMDA receptor to induction of the model immediate-early gene c-fos, whose expression is controlled by several constitutive factors, among them by the CREB (cAMP-response element binding protein), that must be phosphorylated at a critical Ser133, in order to activate transcription. One fast event in response to NMDA receptor activation is translocation of the Ca2+-calmodulin complex to the cell nucleus and activation of Ca2+/calmodulin-dependent protein kinase IV. With slower kinetics, the Ras-MAPK (mitogen-activated protein kinase) kinase cascade is activated, emerging in the signalling to the neuronal nucleus as the most significant pathway, through other specific signalling molecules integrating also signals originally using Ca2+ or cyclic AMP as the second messengers.

• MeSH
• buněčné jádro MeSH
• exprese genu MeSH
• glutamátové receptory MeSH
• kalmodulin MeSH
• neuroplasticita MeSH
• signální transdukce MeSH

Fibrotic diseases are a group of pathologies with high incidence and mortality. Despite extensive research efforts, effective therapies are still not available. Understanding the molecular mechanisms driving the onset, progression and possible resolution of fibrosis is a prerequisite to the development of successful therapies. The central role of the TGF-β pathway and myofibroblasts in the pathogenesis of fibrosis is now generally accepted. The possible mechanisms of myofibroblast elimination or dedifferentiation, on the other hand, are still almost uncharted territory. Here we show that sustained expression of some components of MAPK signaling pathway (PDGFB, Ha-Ras(G12V) or the transcription factor EGR4) in primary chicken embryo dermal myofibroblasts results in a loss of autocrine TGF-β signaling and suppression of the myofibroblastic phenotype, characterized by the loss of alpha smooth muscle actin fibers and a substantial reduction in the production of extracellular matrix. Detailed analysis of the possible molecular mechanisms employed by EGR4 revealed FOXG1, BAMBI, NAB1, NAB2 and DUSP5 genes forming an EGR4 regulated network counteracting autocrine TGF-β signaling. We have also found that a combination of chemical inhibition of TGF-β signaling and perturbation of MAPK signaling with phorbol ester mimics the anti-fibrotic effects of PDGFB, Ha-Ras(G12V) and EGR4.

• MeSH
• aktiny genetika   metabolismus   MeSH
• dediferenciace buněk * MeSH
• forbolové estery farmakologie   MeSH
• kuřecí embryo MeSH
• mitogenem aktivované proteinkinasy metabolismus   MeSH
• myofibroblasty cytologie   metabolismus   MeSH
• signální transdukce MeSH
• transformující růstový faktor beta metabolismus   MeSH
• zvířata MeSH
• Check Tag
• kuřecí embryo MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

MiR-34a acts as tumor suppressor microRNA (miRNA) in several cancers, including multiple myeloma (MM), by controlling the expression of target proteins involved in cell cycle, differentiation and apoptosis. Here, we have investigated the combination between miR-34a and γ-secretase inhibitor (γSI), Sirtinol or zoledronic acid (ZOL) in order to enhance the inhibitory action of this miRNA on its canonical targets such as Notch1 and SIRT1, and on Ras/MAPK-dependent pathways. Our data demonstrate that miR-34a synthetic mimics significantly enhance the anti-tumor activity of all the above-mentioned anti-cancer agents in RPMI 8226 MM cells. We found that γSI enhanced miR-34a-dependent anti-tumor effects by activating the extrinsic apoptotic pathway which could overcome the cytoprotective autophagic mechanism. Moreover, the combination between miR-34a and γSI increased the cell surface calreticulin (CRT) expression, that is well known for triggering anti-tumor immunological response. The combination between miR-34a and Sirtinol induced the activation of an intrinsic apoptotic pathway along with increased surface expression of CRT. Regarding ZOL, we found a powerful growth inhibition after enforced miR-34a expression, which was not likely attributable to neither apoptosis nor autophagy modulation. Based on our data, the combination of miR-34a with other anti-cancer agents appears a promising anti-MM strategy deserving further investigation.

• MeSH
• apoptóza účinky léků   MeSH
• benzamidy terapeutické užití   MeSH
• buněčný cyklus účinky léků   MeSH
• kyselina zoledronová terapeutické užití   MeSH
• lidé MeSH
• mikro RNA terapeutické užití   MeSH
• mnohočetný myelom farmakoterapie   MeSH
• nádorové buněčné linie MeSH
• naftoly terapeutické užití   MeSH
• protinádorové látky terapeutické užití   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH