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
The RAS pathway is among the most frequently activated signaling nodes in cancer. However, the mechanisms that alter RAS activity in human pathologies are not entirely understood. The most prevalent post-translational modification within the GTPase core domain of NRAS and KRAS is ubiquitination at lysine 128 (K128), which is significantly decreased in cancer samples compared to normal tissue. Here, we found that K128 ubiquitination creates an additional binding interface for RAS GTPase-activating proteins (GAPs), NF1 and RASA1, thus increasing RAS binding to GAP proteins and promoting GAP-mediated GTP hydrolysis. Stimulation of cultured cancer cells with growth factors or cytokines transiently induces K128 ubiquitination and restricts the extent of wild-type RAS activation in a GAP-dependent manner. In KRAS mutant cells, K128 ubiquitination limits tumor growth by restricting RAL/ TBK1 signaling and negatively regulating the autocrine circuit induced by mutant KRAS. Reduction of K128 ubiquitination activates both wild-type and mutant RAS signaling and elicits a senescence-associated secretory phenotype, promoting RAS-driven pancreatic tumorigenesis.
- MeSH
- GTP-fosfohydrolasy metabolismus genetika MeSH
- lidé MeSH
- lysin metabolismus MeSH
- membránové proteiny metabolismus genetika MeSH
- myši MeSH
- nádorové buněčné linie MeSH
- neurofibromin 1 MeSH
- protein aktivující GTPasu p120 metabolismus genetika MeSH
- protein-serin-threoninkinasy metabolismus genetika MeSH
- protoonkogenní proteiny p21(ras) * metabolismus genetika MeSH
- Ras proteiny metabolismus genetika MeSH
- signální transdukce MeSH
- ubikvitinace * MeSH
- vazba proteinů * MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Targeting Anaplastic lymphoma kinase (ALK) is a promising therapeutic strategy for aberrant ALK-expressing malignancies including neuroblastoma, but resistance to ALK tyrosine kinase inhibitors (ALK TKI) is a distinct possibility necessitating drug combination therapeutic approaches. Using high-throughput, genome-wide CRISPR-Cas9 knockout screens, we identify miR-1304-5p loss as a desensitizer to ALK TKIs in aberrant ALK-expressing neuroblastoma; inhibition of miR-1304-5p decreases, while mimics of this miRNA increase the sensitivity of neuroblastoma cells to ALK TKIs. We show that miR-1304-5p targets NRAS, decreasing cell viability via induction of apoptosis. It follows that the farnesyltransferase inhibitor (FTI) lonafarnib in addition to ALK TKIs act synergistically in neuroblastoma, inducing apoptosis in vitro. In particular, on combined treatment of neuroblastoma patient derived xenografts with an FTI and an ALK TKI complete regression of tumour growth is observed although tumours rapidly regrow on cessation of therapy. Overall, our data suggests that combined use of ALK TKIs and FTIs, constitutes a therapeutic approach to treat high risk neuroblastoma although prolonged therapy is likely required to prevent relapse.
- MeSH
- anaplastická lymfomová kináza * genetika metabolismus antagonisté a inhibitory MeSH
- apoptóza účinky léků genetika MeSH
- chemorezistence genetika účinky léků MeSH
- dibenzocyklohepteny * MeSH
- farnesyltranstransferasa * antagonisté a inhibitory metabolismus MeSH
- GTP-fosfohydrolasy * genetika metabolismus MeSH
- inhibitory proteinkinas * farmakologie terapeutické užití MeSH
- lidé MeSH
- membránové proteiny metabolismus genetika MeSH
- mikro RNA * genetika metabolismus MeSH
- mutace MeSH
- myši MeSH
- nádorové buněčné linie MeSH
- neuroblastom * farmakoterapie genetika patologie metabolismus MeSH
- piperidiny * farmakologie terapeutické užití MeSH
- pyridiny * farmakologie terapeutické užití MeSH
- regulace genové exprese u nádorů účinky léků MeSH
- synergismus léků MeSH
- xenogenní modely - testy protinádorové aktivity MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The presence of wild-type RAS alleles, as determined by genotyping codons 12, 13, 59, 61, 117, and 146, is a prerequisite for personalized anti-EGFR treatment of metastatic colorectal cancer (mCRC) patients. Here we describe analytical validation of in-house developed massively parallel sequencing technology (MPS) in comparison to the in vitro diagnostics (IVD) certified qPCR method. DNA extracted from FFPE samples from CRC patients (n=703) and reference standards (n=33) were tested for KRAS and NRAS mutations in 6 codons of exons 2, 3, and 4 using deep amplicon sequencing (DAS) on a MiSeq benchtop sequencer (Illumina). Two different amplicon lengths and two different library preparation methods (long-RAS and short-RAS) were tested in order to evaluate their impact on DAS performance. In parallel, identical tumor DNA was tested by the following IVD assays: therascreen KRAS RGQ PCR Kit (Qiagen), cobas® KRAS Mutation Test (Roche Diagnostics), and SNaPshot assay (Thermo Fisher Scientific). Both DAS assays detected all the mutations present in reference standards and external quality control samples, except for the artificially generated KRAS codon 146 mutation. The DAS assays performed sufficient analytical specificity and sensitivity (≥0.95). The use of shorter amplicons prolonged the preparation steps but significantly improved the sequencing success rate of FFPE-derived DNA. RAS mutation frequencies in the Czech CRC patients were similar to previous reports, although rare mutations were also detected. DAS with short amplicons is a good strategy for routine assessment of somatic mutations in low-quality FFPE-derived DNA.
- MeSH
- akutní myeloidní leukemie * diagnóza genetika MeSH
- bodová mutace MeSH
- GTP-fosfohydrolasy genetika MeSH
- lidé MeSH
- membránové proteiny genetika MeSH
- mutace MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Spitzoid melanocytic lesions represent a heterogeneous group of proliferations with ambiguous and overlapping terminology. The exact distinction of a Spitz nevus from a Spitzoid melanoma can be very difficult or, in some cases, impossible. Among the Spitzoid lesions, there is a lesion termed an atypical Spitz tumour (AST) that has intermediate histopathologic features between those of a Spitz nevus and a Spitzoid melanoma and thus uncertain malignant potential. There are several rare cases of patients with a Spitzoid melanoma initially misdiagnosed as a Spitz nevus or an AST with fatal consequences. It is, therefore, advised to perform a molecular characterization in cases where uncertain skin lesions are presented, as it may provide extended set of information with a possible impact on the treatment options. Furthermore, preventive measures, such as regular physical and skin examinations, as well as thorough scheduling of individual follow-up visits, are essential in patients with potentially malignant skin nevi. CASE REPORT: We report a case of a young adult female with a history of AST excision with a negative sentinel lymph node biopsy (SLNB) and insufficient follow-up. Four years after the primary dermatological diagnosis, she presented with a giant tumour in the right hemithorax. Radical en bloc resection of the tumour with right pneumonectomy and resection of the pericardium with reconstruction of the pericardium using mesh was performed. A definitive histopathological examination revealed a metastatic melanoma. The association of the previously diagnosed AST and subsequent appearance of melanoma metastases led to a retrospective re-evaluation of the initial lesion. The suspected diagnosis of Spitzoid melanoma, however, was not confirmed. Moreover, the molecular examination revealed a major discordance between the initial lesion and the lung tumour, which most likely excluded the possible association of the lung metastasis with the initial skin lesion. The initial skin lesion was a BRAF-mutant melanoma with Spitzoid features and termed as AST, while the giant lung metastasis was NRAS-mutant melanoma. The subsequent postoperative course was complicated by the appearance of brain metastases that were stereotactically irradiated. Nevertheless, despite complex specialised medical care, the patient's clinical condition rapidly deteriorated. By this time, no active oncological treatment was possible. The patient was delegated to local hospice for palliative care six months after the surgery and died three weeks later. CONCLUSIONS: Our patient was surgically treated at the age of 20 for AST and died four years later of metastatic NRAS-mutant melanoma most likely of different occult origin. Molecular characterization, as well as the close clinical follow-up should be always precisely performed in patients with uncertain skin lesions, such as AST.
- MeSH
- epiteloidní a vřetenobuněčný névus genetika patologie MeSH
- GTP-fosfohydrolasy genetika MeSH
- lidé MeSH
- melanom genetika sekundární MeSH
- membránové proteiny genetika MeSH
- mladý dospělý MeSH
- mnohočetné primární nádory genetika patologie MeSH
- mutace MeSH
- nádory kůže genetika patologie sekundární MeSH
- nádory plic sekundární MeSH
- protoonkogenní proteiny B-raf genetika MeSH
- Check Tag
- lidé MeSH
- mladý dospělý MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- kazuistiky MeSH
BRCA1-associated protein (BAP1)-inactivated melanocytic tumor (BIMT) is a group of epithelioid melanocytic neoplasms characterized by the loss of function of BAP1, a tumor suppressor gene located on chromosome 3p21. They occur sporadically or in the setting of an autosomal-dominant cancer susceptibility syndrome that predisposes to the development of different internal malignancies. Most of these cutaneous lesions are associated with a BRAF-mutated melanocytic nevus and therefore are included in the group of combined nevi in the last WHO classification of skin tumors. Apart from a BRAF mutation, an NRAS mutation has been reported in rare cases, whereas in some lesions no driver mutation has been detected. Here, we report 2 cases of BIMTs with a BAP1 mutation and a RAF1 fusion. Both lesions proved to be BRAF and NRAS wild type and were associated with a conventional melanocytic nevus with dysplastic junctional features. We suggest that RAF1 fusions can represent an underlying driver genetic event in these cases. Our study extends the morphological and molecular spectrum in BIMTs.
- MeSH
- dítě MeSH
- dospělí MeSH
- fenotyp MeSH
- fúze genů * MeSH
- genetická predispozice k nemoci MeSH
- GTP-fosfohydrolasy genetika MeSH
- imunohistochemie MeSH
- lidé MeSH
- membránové proteiny genetika MeSH
- mutační analýza DNA MeSH
- nádorové biomarkery analýza genetika MeSH
- nádorové supresorové proteiny genetika MeSH
- nádory kůže chemie genetika patologie chirurgie MeSH
- pigmentový névus chemie genetika patologie chirurgie MeSH
- protoonkogenní proteiny B-raf genetika MeSH
- protoonkogenní proteiny c-raf genetika MeSH
- thiolesterasa ubikvitinu genetika MeSH
- umlčování genů * MeSH
- Check Tag
- dítě MeSH
- dospělí MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
AIMS: Ameloblastic fibrosarcoma (AFS) is an aggressive odontogenic neoplasm featuring malignant mesenchymal stroma in addition to an ameloblastic epithelial component, and is hence considered to be the malignant counterpart of ameloblastic fibroma (AF). AFS is exceedingly rare, with <110 cases having been reported so far. Although BRAF mutations are recognised driver mutations in ameloblastoma, the molecular pathogenesis of AFS remains elusive. METHODS AND RESULTS: We herein describe seven AFSs that were analysed, for the first time, for mutations in the BRAF-NRAS pathway. The patients were four females and three males aged 23-57 years (median, 26 years). Three tumours developed after one or multiple recurrences of AF (4-20 years after initial diagnosis), two showed transition from AF-like bland areas, and two developed de novo. All patients were treated with surgery; adjuvant chemotherapy was given to one patient. At the last follow-up, five patients were alive and well (19-344 months). The remainder were lost to follow-up. Histological examination showed variable sarcomatous overgrowth with varying degrees of atypia and increased mitotic activity. The epithelial component varied greatly according to the degree of sarcomatous overgrowth. Molecular testing revealed BRAF V600E mutations in five cases and NRAS p.Gln61Lys mutation in one case. One tumour was wild-type. CONCLUSION: To our knowledge, this is the first study on BRAF/NRAS mutations in AFS. Given the activity of RAF and MEK inhibitors across different cancers harbouring V600E mutations, our data strongly suggest that all AFS cases should be genetically tested, and that targeted treatment approaches for this extremely rare sarcoma subtype should be clinically investigated.
- MeSH
- ameloblastom genetika patologie MeSH
- dospělí MeSH
- fibrosarkom genetika patologie MeSH
- GTP-fosfohydrolasy genetika MeSH
- lidé středního věku MeSH
- lidé MeSH
- membránové proteiny genetika MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mutace MeSH
- nádory čelistí genetika patologie MeSH
- protoonkogenní proteiny B-raf genetika MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Rare cases of hematological precursor neoplasms fulfill the diagnostic criteria of mixed phenotype acute leukemia (MPAL), characterized by expression patterns of at least two hematopoietic lineages, for which a highly aggressive behavior was reported. We present a series of 11 pediatric non-leukemic MPAL identified among 146 precursor lymphoblastic lymphomas included in the prospective trial Euro-LBL 02. Paraffin-embedded biopsies of 10 cases were suitable for molecular analyses using OncoScan assay (n = 7), fluorescence in situ hybridization (FISH; n = 7) or both (n = 5). Except for one case with biallelic KMT2A (MLL) breaks, all cases analyzed by FISH lacked the most common translocations defining molecular subsets of lymphoblastic leukemia/lymphomas. Two non-leukemic B-myeloid MPALs showed the typical genomic profile of hyperdiploid precursor B-cell lymphoblastic leukemia with gains of chromosomes 4, 6, 10, 14, 18, and 21. One B-T MPAL showed typical aberrations of T-cell lymphoblastic lymphoma, such as copy number neutral loss of heterozygosity (CNN-LOH) at 9p targeting a 9p21.3 deletion of CDKN2A and 11q12.2-qter affecting the ATM gene. ATM was also mutated in a T-myeloid MPAL case with additional loss at 7q21.2-q36.3 and mutation of NRAS, two alterations common in myeloid disorders. No recurrent regions of CNN-LOH were observed. The outcome under treatment was good with all patients being alive in first complete remission after treatment according to a protocol for precursor lymphoblastic lymphoma (follow-up 3-10 years, median: 4.9 years). In summary, the present series of non-leukemic MPALs widely lacked recurrently reported translocations in lymphoid/myeloid neoplasias and showed heterogeneous spectrum of chromosomal imbalances.
- MeSH
- akutní lymfatická leukemie farmakoterapie genetika patologie MeSH
- ATM protein genetika MeSH
- dítě MeSH
- fenotyp * MeSH
- GTP-fosfohydrolasy genetika MeSH
- histonlysin-N-methyltransferasa genetika MeSH
- inhibitor p16 cyklin-dependentní kinasy genetika MeSH
- lidé MeSH
- membránové proteiny genetika MeSH
- mladiství MeSH
- nestabilita genomu účinky léků MeSH
- předškolní dítě MeSH
- protinádorové látky škodlivé účinky terapeutické užití MeSH
- protoonkogenní protein MLL genetika MeSH
- translokace genetická * MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- předškolní dítě MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- randomizované kontrolované studie MeSH
Altered cell metabolism is a hallmark of cancer, and targeting specific metabolic nodes is considered an attractive strategy for cancer therapy. In this study, we evaluate the effects of metabolic stressors on the deregulated ERK pathway in melanoma cells bearing activating mutations of the NRAS or BRAF oncogenes. We report that metabolic stressors promote the dimerization of KSR proteins with CRAF in NRAS-mutant cells, and with oncogenic BRAF in BRAFV600E-mutant cells, thereby enhancing ERK pathway activation. Despite this similarity, the two genomic subtypes react differently when a higher level of metabolic stress is induced. In NRAS-mutant cells, the ERK pathway is even more stimulated, while it is strongly downregulated in BRAFV600E-mutant cells. We demonstrate that this is caused by the dissociation of mutant BRAF from KSR and is mediated by activated AMPK. Both types of ERK regulation nevertheless lead to cell cycle arrest. Besides studying the effects of the metabolic stressors on ERK pathway activity, we also present data suggesting that for efficient therapies of both genomic melanoma subtypes, specific metabolic targeting is necessary.
- MeSH
- aktivace enzymů MeSH
- extracelulárním signálem regulované MAP kinasy metabolismus MeSH
- fyziologický stres * MeSH
- glukosa metabolismus MeSH
- glykolýza MeSH
- GTP-fosfohydrolasy genetika metabolismus MeSH
- kontrolní body buněčného cyklu genetika MeSH
- lidé MeSH
- melanom genetika metabolismus MeSH
- membránové proteiny genetika metabolismus MeSH
- multimerizace proteinu * MeSH
- mutace MeSH
- nádorové buněčné linie MeSH
- proteinkinasy chemie genetika metabolismus MeSH
- proteiny 14-3-3 chemie metabolismus MeSH
- raf kinasy chemie genetika metabolismus MeSH
- rekombinantní fúzní proteiny MeSH
- spotřeba kyslíku MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
