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1.
Medicine (Baltimore) ; 99(39): e22257, 2020 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-32991423

RESUMO

Cutaneous squamous cell carcinoma (cSCC) is a common skin cancer with an increasing incidence. As a pre-cancerous condition, actinic keratosis (AK) has an up to 20% risk of progression to cSCC. This study aims to define the potential genes that associated with genesis and progression of cSCC, thereby further identify critical biomarkers for the prevention, early diagnosis, and effective treatment of cSCC.Two datasets GSE42677 and GSE45216 were downloaded from the GEO. Microarray data analysis was applied to explore the differentially expressed genes (DEGs) between cSCC samples and AK samples. Then functional enrichment analysis, protein-protein interaction (PPI) network, and drug-gene interaction analysis were performed to screen key genes.A total of 711 DEGs, including 238 upregulated genes and 473 downregulated genes, were screened out. DEGs mainly involved in pathways as extracellular matrix (ECM)-receptor interaction, hematopoietic cell lineage, phosphatidylinositol 3-kinase (PI3K-Akt) signaling pathway, and focal adhesion. Candidate genes, including upregulated genes as JUN, filamin A (FLNA), casein kinase 1 delta (CSNK1D), and histone cluster 1 H3 family member f (HIST1H3F), and downregulated genes as androgen receptor (AR), heat shock protein family H member 1 (HSPH1), tropomyosin 1 (TPM1), pyruvate kinase, muscle (PKM), LIM domain and actin binding 1 (LIMA1), and synaptopodin (SYNPO) were screened out. In drug-gene interaction analysis, 13 genes and 44 drugs were identified.This study demonstrates that genes JUN, FLNA, AR, HSPH1, and CSNK1D have the potential to function as targets for diagnosis and treatment of cSCC.


Assuntos
Carcinoma de Células Escamosas/genética , Análise em Microsséries/normas , Neoplasias Cutâneas/genética , Biomarcadores Tumorais/genética , Bases de Dados Genéticas , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Ceratose Actínica/genética , Mapas de Interação de Proteínas , Melhoria de Qualidade
2.
N Engl J Med ; 383(12): 1139-1148, 2020 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-32877599

RESUMO

BACKGROUND: In the previously reported primary analysis of this phase 3 trial, 12 months of adjuvant dabrafenib plus trametinib resulted in significantly longer relapse-free survival than placebo in patients with resected stage III melanoma with BRAF V600E or V600K mutations. To confirm the stability of the relapse-free survival benefit, longer-term data were needed. METHODS: We randomly assigned 870 patients who had resected stage III melanoma with BRAF V600E or V600K mutations to receive 12 months of oral dabrafenib (at a dose of 150 mg twice daily) plus trametinib (2 mg once daily) or two matched placebos. The primary end point was relapse-free survival. Here, we report 5-year results for relapse-free survival and survival without distant metastasis as the site of the first relapse. Overall survival was not analyzed, since the required number of events to trigger the final overall survival analysis had not been reached. RESULTS: The minimum duration of follow-up was 59 months (median patient follow-up, 60 months for dabrafenib plus trametinib and 58 months for placebo). At 5 years, the percentage of patients who were alive without relapse was 52% (95% confidence interval [CI], 48 to 58) with dabrafenib plus trametinib and 36% (95% CI, 32 to 41) with placebo (hazard ratio for relapse or death, 0.51; 95% CI, 0.42 to 0.61). The percentage of patients who were alive without distant metastasis was 65% (95% CI, 61 to 71) with dabrafenib plus trametinib and 54% (95% CI, 49 to 60) with placebo (hazard ratio for distant metastasis or death, 0.55; 95% CI, 0.44 to 0.70). No clinically meaningful between-group difference in the incidence or severity of serious adverse events was reported during the follow-up period. CONCLUSIONS: In the 5-year follow-up of a phase 3 trial involving patients who had resected stage III melanoma with BRAF V600E or V600K mutations, 12 months of adjuvant therapy with dabrafenib plus trametinib resulted in a longer duration of survival without relapse or distant metastasis than placebo with no apparent long-term toxic effects. (Funded by GlaxoSmithKline and Novartis; COMBI-AD ClinicalTrials.gov number, NCT01682083; EudraCT number, 2012-001266-15.).


Assuntos
Adjuvantes Imunológicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Imidazóis/uso terapêutico , Melanoma/tratamento farmacológico , Oximas/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/genética , Piridonas/uso terapêutico , Pirimidinonas/uso terapêutico , Neoplasias Cutâneas/tratamento farmacológico , Administração Oral , Adulto , Idoso , Intervalo Livre de Doença , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Masculino , Melanoma/genética , Pessoa de Meia-Idade , Mutação , Metástase Neoplásica , Estadiamento de Neoplasias , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Neoplasias Cutâneas/genética , Análise de Sobrevida
3.
Mutat Res ; 785: 108321, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32800272

RESUMO

BRAF is a member of the RAF family of serine/threonine-specific protein kinases. Oncogenic BRAF, in particular, BRAF V600E, can disturb the normal protein folding machinery in the endoplasmic reticulum (ER) leading to accumulation of unfolded/misfolded proteins in the ER lumen, a condition known as endoplasmic reticulum (ER) stress. To alleviate such conditions, ER-stressed cells have developed a highly robust and adaptable signaling network known as unfolded protein response (UPR). UPR is ordinarily a cytoprotective response and usually operates through the induction of autophagy, an intracellular lysosomal degradation pathway that directs damaged proteins, protein aggregates, and damaged organelles for bulk degradation and recycling. Both ER stress and autophagy are involved in the progression and chemoresistance of melanoma. Melanoma, which arises as a result of malignant transformation of melanocytes, exhibits exceptionally high therapeutic resistance. Many mechanisms of therapeutic resistance have been identified in individual melanoma patients and in preclinical BRAF-driven melanoma models. Recently, it has been recognized that oncogenic BRAF interacts with GRP78 and removes its inhibitory influence on the three fundamental ER stress sensors of UPR, PERK, IRE1α, and ATF6. Dissociation of GRP78 from these ER stress sensors prompts UPR that subsequently activates cytoprotective autophagy. Thus, pharmacological inhibition of BRAF-induced ER stress-mediated autophagy can potentially resensitize BRAF mutant melanoma tumors to apoptosis. However, the underlying molecular mechanism of how oncogenic BRAF elevates the basal level of ER stress-mediated autophagy in melanoma tumors is not well characterized. A better understanding of the crosstalk between oncogenic BRAF, ER stress and autophagy may provide a rationale for improving existing cancer therapies and identify novel targets for therapeutic intervention of melanoma.


Assuntos
Autofagia , Resistencia a Medicamentos Antineoplásicos , Estresse do Retículo Endoplasmático , Melanoma/genética , Proteínas Proto-Oncogênicas B-raf/genética , Neoplasias Cutâneas/genética , Resposta a Proteínas não Dobradas , Apoptose , Humanos , Melanoma/tratamento farmacológico , Transdução de Sinais , Neoplasias Cutâneas/tratamento farmacológico
4.
PLoS Pathog ; 16(8): e1008562, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32833988

RESUMO

Merkel Cell Polyomavirus (MCPyV) is the etiological agent of the majority of Merkel Cell Carcinomas (MCC). MCPyV positive MCCs harbor integrated, defective viral genomes that constitutively express viral oncogenes. Which molecular mechanisms promote viral integration, if distinct integration patterns exist, and if integration occurs preferentially at loci with specific chromatin states is unknown. We here combined short and long-read (nanopore) next-generation sequencing and present the first high-resolution analysis of integration site structure in MCC cell lines as well as primary tumor material. We find two main types of integration site structure: Linear patterns with chromosomal breakpoints that map closely together, and complex integration loci that exhibit local amplification of genomic sequences flanking the viral DNA. Sequence analysis suggests that linear patterns are produced during viral replication by integration of defective/linear genomes into host DNA double strand breaks via non-homologous end joining, NHEJ. In contrast, our data strongly suggest that complex integration patterns are mediated by microhomology-mediated break-induced replication, MMBIR. Furthermore, we show by ChIP-Seq and RNA-Seq analysis that MCPyV preferably integrates in open chromatin and provide evidence that viral oncogene expression is driven by the viral promoter region, rather than transcription from juxtaposed host promoters. Taken together, our data explain the characteristics of MCPyV integration and may also provide a model for integration of other oncogenic DNA viruses such as papillomaviruses.


Assuntos
Carcinoma de Célula de Merkel/patologia , Reparo do DNA por Junção de Extremidades , Poliomavírus das Células de Merkel/genética , Infecções por Polyomavirus/complicações , Infecções Tumorais por Vírus/complicações , Integração Viral , Replicação Viral , Antígenos Virais de Tumores , Neoplasias Ósseas/genética , Neoplasias Ósseas/secundário , Neoplasias Ósseas/virologia , Carcinoma de Célula de Merkel/genética , Carcinoma de Célula de Merkel/virologia , Humanos , Infecções por Polyomavirus/genética , Infecções por Polyomavirus/virologia , Recombinação Genética , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/virologia , Infecções Tumorais por Vírus/genética , Infecções Tumorais por Vírus/virologia , Proteínas Virais/genética
5.
Nat Commun ; 11(1): 3946, 2020 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-32770055

RESUMO

Melanomas can switch to a dedifferentiated cell state upon exposure to cytotoxic T cells. However, it is unclear whether such tumor cells pre-exist in patients and whether they can be resensitized to immunotherapy. Here, we chronically expose (patient-derived) melanoma cell lines to differentiation antigen-specific cytotoxic T cells and observe strong enrichment of a pre-existing NGFRhi population. These fractions are refractory also to T cells recognizing non-differentiation antigens, as well as to BRAF + MEK inhibitors. NGFRhi cells induce the neurotrophic factor BDNF, which contributes to T cell resistance, as does NGFR. In melanoma patients, a tumor-intrinsic NGFR signature predicts anti-PD-1 therapy resistance, and NGFRhi tumor fractions are associated with immune exclusion. Lastly, pharmacologic NGFR inhibition restores tumor sensitivity to T cell attack in vitro and in melanoma xenografts. These findings demonstrate the existence of a stable and pre-existing NGFRhi multitherapy-refractory melanoma subpopulation, which ought to be eliminated to revert intrinsic resistance to immunotherapeutic intervention.


Assuntos
Antineoplásicos Imunológicos/farmacologia , Melanoma/tratamento farmacológico , Proteínas do Tecido Nervoso/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Receptores de Fator de Crescimento Neural/metabolismo , Neoplasias Cutâneas/tratamento farmacológico , Linfócitos T Citotóxicos/imunologia , Animais , Antineoplásicos Imunológicos/uso terapêutico , Fator Neurotrófico Derivado do Encéfalo/antagonistas & inibidores , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Humanos , Masculino , Melanoma/genética , Melanoma/imunologia , Melanoma/patologia , Camundongos , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Proteínas do Tecido Nervoso/antagonistas & inibidores , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/imunologia , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , RNA-Seq , Receptores de Fator de Crescimento Neural/antagonistas & inibidores , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/patologia , Linfócitos T Citotóxicos/metabolismo , Evasão Tumoral/genética , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/genética , Microambiente Tumoral/imunologia , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Nat Commun ; 11(1): 4306, 2020 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-32855398

RESUMO

Metastatic melanoma carries a poor prognosis despite modern systemic therapies. Understanding the evolution of the disease could help inform patient management. Through whole-genome sequencing of 13 melanoma metastases sampled at autopsy from a treatment naïve patient and by leveraging the analytical power of multi-sample analyses, we reveal evidence of diversification among metastatic lineages. UV-induced mutations dominate the trunk, whereas APOBEC-associated mutations are found in the branches of the evolutionary tree. Multi-sample analyses from a further seven patients confirmed that lineage diversification was pervasive, representing an important mode of melanoma dissemination. Our analyses demonstrate that joint analysis of cancer cell fraction estimates across multiple metastases can uncover previously unrecognised levels of tumour heterogeneity and highlight the limitations of inferring heterogeneity from a single biopsy.


Assuntos
Evolução Clonal , Heterogeneidade Genética , Melanoma/genética , Neoplasias Cutâneas/genética , Idoso , Biópsia , Análise Mutacional de DNA , Humanos , Masculino , Melanoma/secundário , Estudos Prospectivos , Pele/patologia , Neoplasias Cutâneas/patologia , Sequenciamento Completo do Genoma
7.
Zhonghua Bing Li Xue Za Zhi ; 49(8): 827-833, 2020 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-32746551

RESUMO

Objective: To investigate the clinical value of the first multicolor fluorescence in situ hybridization (FISH) assay on multiple genes, and combined with 9p21 and 8q24 evaluation in the differential diagnosis of melanoma. Methods: Fifty-six melanomas and 36 benign melanocytic nevi diagnosed in Fudan University Shanghai Cancer Center from 2017 to 2019 were included. Each specimen was examined by first multicolor FISH assay targeting 6p25 (RREB1), 6q23 (MYB), 11q13 (CCND1) and CEP6, as well as 9p21 (CDKN2A) and 8q24 (MYC). The results of FISH assay in all cases were recorded according to Gerami's criteria. Basing on the sensitivity and specificity of the first FISH assay, the refinement of diagnosis by adding combined 9p21 and 8q24 probes was further evaluated, as well as their association with different clinicopathological features. Results: In 86 cases, the FISH signals were adequate for analysis. Of the 56 melanoma cases, 52 cases were adequate for analysis; 36 cases (69.2%) were positive in the first FISH assay. The most frequent chromosomal anomaly was gain of RREB1 (30/52, 57.7%), followed by gain of CCND1 (20/52, 38.5%), loss of MYB relative to CEP6 (18/52, 34.6%) and gain of RREB1 relative to CEP6 (17/52, 32.7%). The frequency of homozygous deletions in 9p21 was 15.4% (8/52) and gain of 8q24 was 36.5% (19/52). Among the 36 melanocytic nevi cases, FISH results could be accurately evaluated in 34 cases, and none showed a positive result in the first FISH assay or 9p21 and 8q24 FISH analysis. Compared with the first FISH assay, the sensitivity of combination with 9p21 and 8q24 FISH analysis increased from 69.2% to 76.9% (40/52) and the specificity remained 100.0%. Statistical data showed that the rates of FISH positivity in patients with acral-lentiginious melanoma and nodual melanoma subtypes were higher than that in patients with superficial spreading melanoma and lentigo maligna melanoma subtypes, and patients with Breslow thickness>2.0 mm had higher positive FISH frequency than patients with Breslow thickness ≤2.0 mm. Conclusion: Multisite FISH analysis is a highly effective ancillary tool for the differentiation of unequivocal malignant from benign melanocytic lesions. By combining the first FISH assay with CDKN2A and MYC assay, the clinical utility of FISH analysis is further optimized in differential diagnosis of melanoma. Patients with Breslow thickness>2.0 mm, or acral-lentiginious melanoma and nodual melanoma subtypes tend to have higher FISH positivity. There remains a need to further explore the ancillary value of FISH analysis in diagnosis of ambiguous lesions.


Assuntos
Melanoma/diagnóstico , Melanoma/genética , Nevo Pigmentado , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/genética , China , Diagnóstico Diferencial , Humanos , Hibridização in Situ Fluorescente
8.
Yonsei Med J ; 61(7): 562-571, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32608199

RESUMO

Melanoma, originating from epidermal melanocytes, is a heterogeneous disease that has the highest mortality rate among all types of skin cancers. Numerous studies have revealed the cause of this cancer as related to various somatic driver mutations, including alterations in KIT-a proto-oncogene encoding for a transmembrane receptor tyrosine kinase. Although accounting for only 3% of all melanomas, mutations in c-KIT are mostly derived from acral, mucosal, and chronically sun-damaged melanomas. As an important factor for cell differentiation, proliferation, and survival, inhibition of c-KIT has been exploited for clinical trials in advanced melanoma. Here, apart from the molecular background of c-KIT and its cellular functions, we will review the wide distribution of alterations in KIT with a catalogue of more than 40 mutations reported in various articles and case studies. Additionally, we will summarize the association of KIT mutations with clinicopathologic features (age, sex, melanoma subtypes, anatomic location, etc.), and the differences of mutation rate among subgroups. Finally, several therapeutic trials of c-KIT inhibitors, including imatinib, dasatinib, nilotinib, and sunitinib, will be analyzed for their success rates and limitations in advanced melanoma treatment. These not only emphasize c-KIT as an attractive target for personalized melanoma therapy but also propose the requirement for additional investigational studies to develop novel therapeutic trials co-targeting c-KIT and other cytokines such as members of signaling pathways and immune systems.


Assuntos
Antineoplásicos/uso terapêutico , Biomarcadores Tumorais/metabolismo , Resistencia a Medicamentos Antineoplásicos/genética , Melanoma/tratamento farmacológico , Melanoma/metabolismo , Proteínas Proto-Oncogênicas c-kit/uso terapêutico , Transdução de Sinais/efeitos dos fármacos , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/metabolismo , Feminino , Humanos , Masculino , Melanoma/genética , Membrana Mucosa/metabolismo , Mutação , Proteínas Proto-Oncogênicas c-kit/genética , Proteínas Proto-Oncogênicas c-kit/metabolismo , Receptores Proteína Tirosina Quinases/genética , Neoplasias Cutâneas/genética
9.
Cancer Treat Rev ; 88: 102060, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32619863

RESUMO

Phenotypic plasticity of malignant melanoma is a well-known phenomenon. Several translational studies and small case series have reported this clinical and biological entity, particularly in metastatic melanoma, showing frequent aberrant expression of non-melanocytic differentiation markers of different lineages, posing remarkable challenges due to several alternative differential diagnoses including undifferentiated carcinoma and sarcomas. When melanoma loses its typical morpho-phenotype by routinely used diagnostic immunohistochemical markers, it is defined as "dedifferentiated melanoma". Historically, this process was closely related to diagnostic interpretative difficulties. In recent years, however, dedifferentiation has been increasingly recognized as an important biological phenomenon that demonstrates the phenotypic and genetic plasticity of melanoma, and specifically the non-irreversibility of the multistep cancerogenesis. Furthermore, dedifferentiation emerged as a general hallmark of cancer evolution and a common denominator of cross-resistance to both targeted and immunotherapy. In this review, we summarize the histopathological features, the genetic and epigenetic bases underlying the dedifferentiated phenotype in melanomas and provide additional support that dedifferentiation is a mechanism of resistance to immunotherapy and targeted therapy.


Assuntos
Melanoma/genética , Melanoma/terapia , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/terapia , Animais , Desdiferenciação Celular/fisiologia , Reprogramação Celular/fisiologia , Epigênese Genética , Humanos , Melanoma/patologia , Neoplasias Cutâneas/patologia
10.
Nat Commun ; 11(1): 3599, 2020 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-32680990

RESUMO

Notwithstanding the central biological role of the (6-4) photoadduct in the induction of skin cancer by sunlight, crucial mechanistic details about its formation have evaded characterization despite efforts spanning more than half a century. 4-Thiothymidine (4tT) has been widely used as an important model system to study its mechanism of formation, but the excited-state precursor, the intermediate species, and the time scale leading to the formation of the (6-4) photoadduct have remained elusive. Herein, steady-state and time-resolved spectroscopic techniques are combined with new and reported quantum-chemical calculations to demonstrate the excited state leading to the formation of the thietane intermediate, its rate, and the formation of the (6-4) photoadduct using the 5'-TT(4tT)T(4tT)TT-3' DNA oligonucleotide. Efficient, sub-1 ps intersystem crossing leads to the population of a triplet minimum of the thietane intermediate in as short as 3 ps, which intersystem crosses to its ground state and rearranges to form the (6-4) photoadduct.


Assuntos
Adutos de DNA/genética , DNA/genética , Neoplasias Cutâneas/genética , Tionucleosídeos/química , Timidina/análogos & derivados , Raios Ultravioleta/efeitos adversos , DNA/química , Adutos de DNA/efeitos da radiação , Humanos , Estrutura Molecular , Conformação de Ácido Nucleico/efeitos da radiação , Neoplasias Cutâneas/etiologia , Timidina/química
11.
Anticancer Res ; 40(6): 3423-3427, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32487640

RESUMO

BACKGROUND: Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary disease with complete penetrance and a very variable phenotype. Recent research has shown that postzygotic NF1 gene mutations occur to a far greater extent than previously thought. The phenotype of affected individuals reflects the time of somatic mutation and the phenotype is correspondingly diverse. This report describes histological and genetic findings in a case of mosaic NF1, the clinical control of which documents almost stationary skin findings over a period of 9 years. CASE REPORT: The 55-year-old female first presented for advice on a strip of nodular skin tumours of the calf skin. She had no hallmarks of NF1. It was only 9 years later that she had the skin tumours removed, all of which were partially diffuse and partially plexiform neurofibroma. The genetic examination showed an atypical large deletion of the NF1 gene in the skin tumours, but not in overlying skin or blood. CONCLUSION: Segmental NF1 is a distinct type of mosaic/somatic NF1 mutation. The phenotype of diffuse and plexiform skin neurofibromas can resemble cutaneous neurofibroma. Surgical therapy for segmental neurofibromatosis does not differ from the concepts for treating nerve sheath tumours in NF1 patients with a germline NF1 mutation.


Assuntos
Mosaicismo , Neurofibroma Plexiforme/diagnóstico , Neurofibroma Plexiforme/genética , Neurofibromatose 1/diagnóstico , Neurofibromatose 1/genética , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/genética , Biópsia , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Testes Genéticos , Humanos , Perna (Membro)/patologia , Pessoa de Meia-Idade
12.
Mol Genet Genomics ; 295(5): 1239-1252, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32529263

RESUMO

The genetic mechanisms underlying cutaneous melanoma onset and progression need to be further understood to improve patients' care. Several studies have focused on the genetic determinism of melanoma development in the MeLiM pig, a biomedical model of cutaneous melanoma. The objective of this study was to better describe the influence of a particular genomic region on melanoma progression in the MeliM model. Indeed, a large region of the Sus scrofa chromosome 1 has been identified by linkage and association analyses, but the causal mechanisms have remained elusive. To deepen the analysis of this candidate region, a dedicated SNP panel was used to fine map the locus, downsizing the interval to less than 2 Mb, in a genomic region located within a large gene desert. Transcription from this locus was addressed using a tiling array strategy and further validated by RT-PCR in a large panel of tissues. Overall, the gene desert showed an extensive transcriptional landscape, notably dominated by repeated element transcription in tumor and fetal tissues. The transcription of LINE-1 and PERVs has been confirmed in skin and tumor samples from MeLiM pigs. In conclusion, although this study still does not identify a candidate mutation for melanoma occurrence or progression, it highlights a potential role of repeated element transcriptional activity in the MeLiM model.


Assuntos
Cromossomos de Mamíferos/genética , Perfilação da Expressão Gênica/veterinária , Elementos Nucleotídeos Longos e Dispersos , Melanoma/genética , Polimorfismo de Nucleotídeo Único , Neoplasias Cutâneas/genética , Animais , Mapeamento Cromossômico , Modelos Animais de Doenças , Progressão da Doença , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Sus scrofa , Suínos
13.
Proc Natl Acad Sci U S A ; 117(24): 13730-13739, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32482869

RESUMO

Merkel cell carcinoma (MCC) is a lethal skin cancer that metastasizes rapidly. Few effective treatments are available for patients with metastatic MCC. Poor intratumoral T cell infiltration and activation are major barriers that prevent MCC eradication by the immune system. However, the mechanisms that drive the immunologically restrictive tumor microenvironment remain poorly understood. In this study, we discovered that the innate immune regulator stimulator of IFN genes (STING) is completely silenced in MCCs. To reactivate STING in MCC, we developed an application of a human STING mutant, STINGS162A/G230I/Q266I, which we found to be readily stimulated by a mouse STING agonist, DMXAA. This STING molecule was efficiently delivered to MCC cells via an AAV vector. Introducing STINGS162A/G230I/Q266I expression and stimulating its activity by DMXAA in MCC cells reactivates their antitumor inflammatory cytokine/chemokine production. In response to MCC cells with restored STING, cocultured T cells expressing MCPyV-specific T cell receptors (TCRs) show increased cytokine production, migration toward tumor cells, and tumor cell killing. Our study therefore suggests that STING deficiency contributes to the immune suppressive nature of MCCs. More importantly, DMXAA stimulation of STINGS162A/G230I/Q266I causes robust cell death in MCCs as well as several other STING-silenced cancers. Because tumor antigens and DNA released by dying cancer cells have the potential to amplify innate immune response and activate antitumor adaptive responses, our finding indicates that targeted delivery and activation of STINGS162A/G230I/Q266I in tumor cells holds great therapeutic promise for the treatment of MCC and many other STING-deficient cancers.


Assuntos
Carcinoma de Célula de Merkel/imunologia , Proteínas de Membrana/imunologia , Neoplasias Cutâneas/imunologia , Carcinoma de Célula de Merkel/genética , Linhagem Celular Tumoral , Humanos , Imunidade Inata , Proteínas de Membrana/genética , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Transdução de Sinais/efeitos dos fármacos , Neoplasias Cutâneas/genética , Xantonas/farmacologia
14.
Ann Afr Med ; 19(2): 150-152, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32499474

RESUMO

Neurofibromatosis type 1 is the most common inherited nervous system disorder affecting 1 in 3500 live births. Cutaneous neurofibromas, the most characteristic feature of the disease, begin to appear in adolescence and continue throughout adulthood. Although neurofibromas have been noted to increase in size or number during pregnancy, there have been very few reports of eruption of a large number of lesions during this period. We report a case of a 24-year-old Nigerian woman of 32-week gestation who presented with a history of sudden eruption of neurofibromas during the current pregnancy and the previous one 3 years earlier. We discuss how hormones and growth factors contribute to the increase in numbers of neurofibromas during pregnancy, which is occasionally severe, as in our case, and the complications which may arise in the mother and fetus.


Assuntos
Neurofibroma/patologia , Neurofibromatose 1/patologia , Complicações Neoplásicas na Gravidez/patologia , Neoplasias Cutâneas/patologia , Feminino , Humanos , Neurofibroma/genética , Neurofibromatose 1/genética , Gravidez , Pele/patologia , Neoplasias Cutâneas/genética , Adulto Jovem
15.
Mol Cell ; 79(3): 472-487.e10, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32531202

RESUMO

It is widely assumed that decreasing transcription factor DNA-binding affinity reduces transcription initiation by diminishing occupancy of sequence-specific regulatory elements. However, in vivo transcription factors find their binding sites while confronted with a large excess of low-affinity degenerate motifs. Here, using the melanoma lineage survival oncogene MITF as a model, we show that low-affinity binding sites act as a competitive reservoir in vivo from which transcription factors are released by mitogen-activated protein kinase (MAPK)-stimulated acetylation to promote increased occupancy of their regulatory elements. Consequently, a low-DNA-binding-affinity acetylation-mimetic MITF mutation supports melanocyte development and drives tumorigenesis, whereas a high-affinity non-acetylatable mutant does not. The results reveal a paradoxical acetylation-mediated molecular clutch that tunes transcription factor availability via genome-wide redistribution and couples BRAF to tumorigenesis. Our results further suggest that p300/CREB-binding protein-mediated transcription factor acetylation may represent a common mechanism to control transcription factor availability.


Assuntos
Regulação Neoplásica da Expressão Gênica , Genoma , Melanoma/genética , Fator de Transcrição Associado à Microftalmia/genética , Processamento de Proteína Pós-Traducional , Neoplasias Cutâneas/genética , Acetilação , Sequência de Aminoácidos , Animais , Sítios de Ligação , Linhagem Celular Tumoral , Sequência Conservada , Elementos Facilitadores Genéticos , Feminino , Xenoenxertos , Humanos , Masculino , Melanócitos/metabolismo , Melanócitos/patologia , Melanoma/metabolismo , Melanoma/patologia , Camundongos , Camundongos Nus , Fator de Transcrição Associado à Microftalmia/química , Fator de Transcrição Associado à Microftalmia/metabolismo , Motivos de Nucleotídeos , Regiões Promotoras Genéticas , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Peixe-Zebra
16.
Nat Commun ; 11(1): 2858, 2020 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-32504051

RESUMO

Metastatic melanoma is challenging to manage. Although targeted- and immune therapies have extended survival, most patients experience therapy resistance. The adaptability of melanoma cells in nutrient- and therapeutically-challenged environments distinguishes melanoma as an ideal model for investigating therapy resistance. In this review, we discuss the current available repertoire of melanoma models including two- and three-dimensional tissue cultures, organoids, genetically engineered mice and patient-derived xenograft. In particular, we highlight how each system recapitulates different features of melanoma adaptability and can be used to better understand melanoma development, progression and therapy resistance.


Assuntos
Antinematódeos/farmacologia , Modelos Animais de Doenças , Melanoma/tratamento farmacológico , Neoplasias Cutâneas/tratamento farmacológico , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , Animais , Antinematódeos/uso terapêutico , Biomarcadores Tumorais/antagonistas & inibidores , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Técnicas de Cultura de Células , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Melanoma/genética , Melanoma/imunologia , Melanoma/patologia , Camundongos , Camundongos Transgênicos , Organoides , Pele/citologia , Pele/imunologia , Pele/patologia , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/patologia , Esferoides Celulares
18.
Nat Cell Biol ; 22(7): 758-766, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32483388

RESUMO

Cancer-associated fibroblasts (CAFs) perform diverse roles and can modulate therapy responses1. The inflammatory environment within tumours also influences responses to many therapies, including the efficacy of oncolytic viruses2; however, the role of CAFs in this context remains unclear. Furthermore, little is known about the cell signalling triggered by heterotypic cancer cell-fibroblast contacts and about what activates fibroblasts to express inflammatory mediators1,3. Here, we show that direct contact between cancer cells and CAFs triggers the expression of a wide range of inflammatory modulators by fibroblasts. This is initiated following transcytosis of cytoplasm from cancer cells into fibroblasts, leading to the activation of STING and IRF3-mediated expression of interferon-ß1 and other cytokines. Interferon-ß1 then drives interferon-stimulated transcriptional programs in both cancer cells and stromal fibroblasts and ultimately undermines the efficacy of oncolytic viruses, both in vitro and in vivo. Further, targeting IRF3 solely in stromal fibroblasts restores oncolytic herpes simplex virus function.


Assuntos
Fibroblastos Associados a Câncer/imunologia , Instabilidade Genômica , Fator Regulador 3 de Interferon/metabolismo , Proteínas de Membrana/metabolismo , Terapia Viral Oncolítica , Neoplasias Cutâneas/imunologia , Células Estromais/imunologia , Adulto , Animais , Fibroblastos Associados a Câncer/metabolismo , Fibroblastos Associados a Câncer/patologia , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/imunologia , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/terapia , Células Cultivadas , Citocinas , Interações Hospedeiro-Patógeno , Humanos , Fator Regulador 3 de Interferon/genética , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Vírus Oncolíticos/genética , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/terapia , Células Estromais/metabolismo , Células Estromais/patologia , Ensaios Antitumorais Modelo de Xenoenxerto
19.
Virchows Arch ; 477(1): 121-130, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32388720

RESUMO

Overlapping histological features between benign and malignant lesions and a lack of firm diagnostic criteria for malignancy result in high rates of inter-observer variation in the diagnosis of melanocytic lesions. We aimed to investigate the differential expression of five miRNAs (21, 200c, 204, 205, and 211) in benign naevi (n = 42), dysplastic naevi (n = 41), melanoma in situ (n = 42), and melanoma (n = 42) and evaluate their potential as diagnostic biomarkers of melanocytic lesions. Real-time PCR showed differential miRNA expression profiles between benign naevi; dysplastic naevi and melanoma in situ; and invasive melanoma. We applied a random forest machine learning algorithm to classify cases based on their miRNA expression profiles, which resulted in a ROC curve analysis of 0.99 for malignant melanoma and greater than 0.9 for all other groups. This indicates an overall very high accuracy of our panel of miRNAs as a diagnostic biomarker of benign, dysplastic, and malignant melanocytic lesions. However, the impact of variable lesion percentage and spatial expression patterns of miRNAs on these real-time PCR results was also considered. In situ hybridisation confirmed the expression of miRNA 21 and 211 in melanocytes, while demonstrating expression of miRNA 205 only in keratinocytes, thus calling into question its value as a biomarker of melanocytic lesions. In conclusion, we have validated some miRNAs, including miRNA 21 and 211, as potential diagnostic biomarkers of benign, dysplastic, and malignant melanocytic lesions. However, we also highlight the crucial importance of considering tissue morphology and spatial expression patterns when using molecular techniques for the discovery and validation of new biomarkers.


Assuntos
Biomarcadores/análise , Síndrome do Nevo Displásico/patologia , Hiperplasia/patologia , Melanoma/genética , MicroRNAs/genética , Neoplasias Cutâneas/genética , Diagnóstico Diferencial , Síndrome do Nevo Displásico/diagnóstico , Síndrome do Nevo Displásico/metabolismo , Humanos , Hiperplasia/diagnóstico , Hiperplasia/metabolismo , Melanócitos/metabolismo , Melanócitos/patologia , Melanoma/patologia , Nevo Pigmentado/diagnóstico , Nevo Pigmentado/patologia , Neoplasias Cutâneas/patologia
20.
Am J Surg Pathol ; 44(6): 776-781, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32412717

RESUMO

Unlike systemic anaplastic large cell lymphoma, the vast majority of primary cutaneous anaplastic large cell lymphomas (C-ALCL) do not carry translocations involving the ALK gene and do not express ALK. Expression of ALK protein therefore strongly suggests secondary cutaneous involvement of a systemic anaplastic large cell lymphoma. Recent studies described a small subgroup of ALK-positive C-ALCL, but information on frequency, prognosis, and translocation partners is virtually lacking. A total of 6/309 (2%) C-ALCL patients included in the Dutch registry for cutaneous lymphomas between 1993 and 2019 showed immunohistochemical ALK expression. Clinical and histopathologic characteristics, immunophenotype and disease course were evaluated. Underlying ALK translocations were analyzed with anchored multiplex polymerase chain reaction-based targeted next-generation sequencing. Median age at diagnosis was 39 years (range: 16 to 53 y). All patients presented with a solitary lesion. Treatment with radiotherapy (n=5) or anthracycline-based chemotherapy (n=1) resulted in complete responses in all 6 patients. Three patients developed a relapse, of whom 2 extracutaneous. After a median follow-up of 41 months, 5 patients were alive without disease and 1 patient died of lymphoma. Immunohistochemically, 3 cases (50%) showed combined nuclear and cytoplasmic ALK expression with underlying NPM1-ALK fusions, while 3 cases (50%) showed solely cytoplasmic ALK expression with variant ALK fusion partners (TRAF1, ATIC, TPM3). ALK-positive C-ALCL is extremely uncommon, has a comparable favorable prognosis to ALK-negative C-ALCL, and should be treated in the same way with radiotherapy as first-line treatment.


Assuntos
Quinase do Linfoma Anaplásico/genética , Linfoma Anaplásico Cutâneo Primário de Células Grandes/genética , Linfoma Anaplásico Cutâneo Primário de Células Grandes/patologia , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Adolescente , Adulto , Quinase do Linfoma Anaplásico/metabolismo , Feminino , Humanos , Linfoma Anaplásico Cutâneo Primário de Células Grandes/metabolismo , Masculino , Pessoa de Meia-Idade , Neoplasias Cutâneas/metabolismo , Adulto Jovem
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