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PURPOSE: The role of dual-specificity phosphatase-5 (DUSP5) in BRAF-mutant thyroid cancers remains unclear. The aims of this study are to investigate the role of DUSP5 in BRAF-mutant thyroid cancer cells, explore its value in the diagnosis and evaluate therapeutic potential of targeting DUSP5 combined with sorafenib for BRAF-mutant thyroid cancer patients. METHODS: The role of DUSP5 in thyroid cancer cells was determined by a series of in vitro and in vivo experiments. Underlying mechanisms were explored by western blotting analysis. The diagnostic value of combination detection of DUSP5 expression and BRAFV600E mutation was evaluated using ROC curve. RESULTS: Knocking down DUSP5 in BRAF-mutant thyroid cancer cells significantly inhibited colony formation, cell migration and invasion, meanwhile, induced cell cycle arrest and cell apoptosis. Moreover, inhibition of DUSP5 improved the anti-tumor efficacy of sorafenib both in vitro and in vivo. Besides, combination detection of DUSP5 expression and BRAFV600E mutation showed much more accuracy in preoperative diagnosis of thyroid cancer. CONCLUSIONS: Our data demonstrate an oncogenic role of DUSP5 in BRAF-mutant thyroid cancer cells, and combined analysis of its expression and BRAFV600E mutation can accurately diagnose thyroid cancer. In addition, inhibition of DUSP5 improves the response of BRAF-mutant thyroid cancer cells to sorafenib.
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Antineoplásicos , Proteínas Proto-Oncogênicas B-raf , Sorafenibe , Neoplasias da Glândula Tireoide , Sorafenibe/farmacologia , Sorafenibe/uso terapêutico , Humanos , Proteínas Proto-Oncogênicas B-raf/genética , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/tratamento farmacológico , Neoplasias da Glândula Tireoide/patologia , Linhagem Celular Tumoral , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Fosfatases de Especificidade Dupla/genética , Fosfatases de Especificidade Dupla/metabolismo , Animais , Mutação , Feminino , Masculino , Movimento Celular/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Camundongos , Pessoa de Meia-Idade , Proliferação de Células/efeitos dos fármacos , FenótipoRESUMO
Gliomas are the most common primary intracranial tumor worldwide. The maintenance of telomeres serves as an important biomarker of some subtypes of glioma. In order to investigate the biological role of RTEL1 in glioma. Relative telomere length (RTL) and RTEL1 mRNA was explored and regression analysis was performed to further examine the relationship of the RTL and the expression of RTEL1 with clinicopathological characteristics of glioma patients. We observed that high expression of RTEL1 is positively correlated with telomere length in glioma tissue, and serve as a poor prognostic factor in TERT wild-type patients. Further in vitro studies demonstrate that RTEL1 promoted proliferation, formation, migration and invasion ability of glioma cells. In addition, in vivo studies also revealed the oncogene role of RTEL1 in glioma. Further study using RNA sequence and phospho-specific antibody microarray assays identified JNK/ELK1 signaling was up-regulated by RTEL1 in glioma cells through ROS. In conclusion, our results suggested that RTEL1 promotes glioma tumorigenesis through JNK/ELK1 cascade and indicate that RTEL1 may be a prognostic biomarker in gliomas.
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Neoplasias Encefálicas , Glioma , Humanos , Glioma/patologia , Neoplasias Encefálicas/genética , Transformação Celular Neoplásica/genética , Oncogenes , Biomarcadores , Proliferação de Células , Proteínas Elk-1 do Domínio ets/genética , DNA Helicases/genéticaRESUMO
BACKGROUND: Newborn screening (NBS) aims to detect congenital anomalies, and next-generation sequencing (NGS) has shown promise in this aspect. However, the NBS strategy for monogenic inherited diseases in China remains insufficient. METHODS: We developed a NeoEXOME panel comprising 601 genes that are relevant to the Chinese population found through extensive research on available databases. An interpretation system to grade the results into positive (high-risk, moderate-risk, and low-risk genotypes), negative, and carrier according to the American College of Medical Genetics (ACMG) guidelines was also developed. We validated the panel to evaluate its efficacy by using data from the "1000 Genomes Project" and conducted a pilot multicenter study involving 3423 neonates. RESULTS: The NGS positive rate in the 1000 Genomes Project was 7.6% (23/301), whereas the rate was 12.0% in the multicenter study, including 3249 recruited neonates. Notably, in 200 neonates, positive per conventional NBS, 58.5% (69/118) showed results consistent with NGS. In the remaining 3049 neonates showing negative results in conventional NBS, 271 (8.9%) were positive per NGS, and nine of them were clinically diagnosed with diseases in the follow-up. CONCLUSION: We successfully designed a NeoEXOME panel for targeted sequencing of monogenic inherited diseases in NBS. The panel demonstrated high performance in the Chinese population, particularly for the early detection of diseases with no biochemical markers.
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Sequenciamento de Nucleotídeos em Larga Escala , Triagem Neonatal , Humanos , Recém-Nascido , Projetos Piloto , Sequenciamento do Exoma , Triagem Neonatal/métodos , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala/métodosRESUMO
Lanthanide clusters with good stability and intriguing physical properties are attractive in many fields. By reacting 9-anthracenylphosphonic acid (AnPO3H2) and lanthanide nitrates under solvothermal conditions, we obtained a series of hexanuclear lanthanide phosphonate cages [H3O][Ln6(PO4)(AnPO3)8(DMF)6]·2DMF·H2O (Ln6, Ln = NdIII, EuIII, GdIII, DyIII, HoIII, ErIII, YbIII). Within the cluster, the six Ln atoms form an octahedron and its eight faces are covered by phosphonate groups. The in situ generated phosphate anion resides inside the cage and binds to the six Ln atoms via its four oxygen atoms. Photoluminescence studies show that Nd6, Er6 and Yb6 can emit near-infrared (NIR) luminescence due to the energy transfer from the anthracene ligand to the lanthanide ions. Magnetic studies reveal the magnetocaloric effect of Gd6 with an entropy change (-ΔSm) of 25.92 J kg-1 K-1 at 2.5 K and ΔH = 0-7 T. The possibility of using Gd6 as a contrast agent for magnetic resonance imaging was also explored with longitudinal (r1) and transverse (r2) relaxivities of 5.68 mM-1 s-1 per Gd and 158.11 mM-1 s-1 per Gd, respectively.
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Breast cancer is the most common female tumors arising worldwide, and genetic and epigenetic events are constantly accumulated in breast tumorigenesis. The melastatin-related transient receptor potential 7 channel (TRPM7) is a nonselective cation channel, mainly maintaining Zn2+, Ca2+ and Mg2+ homeostasis. It is also involved in regulating proliferation and migration in various cancers including breast cancer. However, epigenetic alterations (such as promoter methylation) of TRPM7 and their correlation with clinical outcomes in breast cancer patients remain largely unclear. In this study, we found that TRPM7 was highly expressed in the luminal A subtype of breast cancers but no other subtypes compared with GTEx (Genotype-Tissue Expression Rad) or normal samples by analyzing the TCGA database. Correspondingly, TRPM7 was methylated in 42.7% (93 of 219) of breast cancers. Further studies found that promoter methylation of TRPM7 were significantly associated with better clinical outcomes in breast cancer patients, especially in the Luminal A subtype. Besides, methylated TRPM7 was correlated with less number of metastatic lymph nodes and longer local failure free survival time in this subtype. In summary, our data indicate that promoter methylation of TRPM7 may predict poor prognosis in patients with luminal A breast cancer.
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Neoplasias da Mama , Canais de Cátion TRPM , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Metilação de DNA , Feminino , Humanos , Prognóstico , Regiões Promotoras Genéticas , Proteínas Serina-Treonina Quinases/genética , Canais de Cátion TRPM/genética , Canais de Cátion TRPM/metabolismoRESUMO
RAD21 plays multiple roles in numerous cancers. In breast cancer (BC), a high level of RAD21 correlates with poor disease outcomes and resistance to chemotherapy. However, data regarding RAD21 promoter methylation in BC tissue and its correlation with clinical outcomes in patients with BC remain limited. Here, we investigated the clinicopathological features associated with the methylation status of RAD21 in BC to figure out its possible role in pathogenesis and the formation of breast carcinogenesis. The methylation status of the RAD21 gene was significantly associated with better clinical outcomes in patients with BC.
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Neoplasias da Mama , Proteínas de Ciclo Celular , Proteínas de Ligação a DNA , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona , Metilação de DNA , Proteínas de Ligação a DNA/genética , Feminino , Humanos , Prognóstico , Regiões Promotoras Genéticas , CoesinasRESUMO
HACE1, an E3 ubiquitin-protein ligase, is frequently inactivated and has been evidenced as a putative tumor suppressor in different types of cancer. However, its role in glioma remains elusive. Here, we observed increased expression of HACE1 in gliomas related to control subjects, and found a strong correlation of high HACE1 expression with poor prognosis in patients with WHO grade III and IV as well as low-grade glioma (LGG) patients receiving radiotherapy. HACE1 knockdown obviously suppressed malignant behaviors of glioma cells, while ectopic expression of HACE1 enhanced cell growth in vitro and in vivo. Further studies revealed that HACE1 enhanced protein stability of nuclear factor erythroid 2-related factor 2 (NRF2) by competitively binding to NRF2 with another E3 ligase KEAP1. Besides, HACE1 also promoted internal ribosome entry site (IRES)-mediated mRNA translation of NRF2. These effects did not depend on its E3 ligase activity. Finally, we demonstrated that HACE1 dramatically reduced cellular ROS levels by activating NRF2, thereby decreasing the response of glioma cells to radiation. Altogether, our data demonstrate that HACE1 causes enhanced malignant phenotypes and decreased radiosensitivity of glioma cells by activating NRF2, and indicate that it may act as the role of prognostic factor and potential therapeutic target in glioma.
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Glioma/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Proteínas de Neoplasias/metabolismo , Tolerância a Radiação , Ubiquitina-Proteína Ligases/metabolismo , Linhagem Celular Tumoral , Glioma/genética , Glioma/radioterapia , Humanos , Fator 2 Relacionado a NF-E2/genética , Proteínas de Neoplasias/genética , Ubiquitina-Proteína Ligases/genéticaRESUMO
Neurofibromatosis type 1 (NF1), an autosomal dominant and multisystem disorder, is generally considered to be caused by NF1 inactivation. However, there are also numerous studies showing that Neurofibromatosis type 1-like phenotype can be caused by the abnormalities in the other genes. Through targeted parallel sequencing, whole-exome sequencing, de novo genomic sequencing, and RNA isoform sequencing, we identified a germline V2097M variation in CSPG4 gene probably increased susceptibility to a NF1-like phenotype family. Besides, a series of in vitro functional studies revealed that this variant promoted cell proliferation by activating the MAPK/ERK signaling pathway via hindering ectodomain cleavage of CSPG4. Our data demonstrate that a germline variation in the CSPG4 gene might be a high risk to cause NF1-like phenotype. To our knowledge, this is the first report of mutations in the CSPG4 gene in human diseases.
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Proteoglicanas de Sulfatos de Condroitina/genética , Células Germinativas/metabolismo , Proteínas de Membrana/genética , Mutação/genética , Neurofibromatose 1/genética , Neurofibromatose 1/patologia , Adulto , Sequência de Aminoácidos , Linhagem Celular Tumoral , Proliferação de Células/genética , Pré-Escolar , Proteoglicanas de Sulfatos de Condroitina/química , Família , Feminino , Predisposição Genética para Doença , Humanos , Lactente , Sistema de Sinalização das MAP Quinases , Masculino , Proteínas de Membrana/química , Pessoa de Meia-Idade , Modelos Biológicos , Neurofibromatose 1/diagnóstico por imagem , Linhagem , Fenótipo , Adulto JovemRESUMO
Novel coronavirus (2019-nCov) infection (COVID-19) rapidly spread across China and 25 countries in the worldwide, which infected not only adults but also children, even neonates. Each year, about 15 million newborns are delivered in China. Newborn screening (NBS) helps effectively prevent some mental retardation, premature death, and adverse outcomes in the early stage of baby, which could detect some inherited metabolic disorders (IMDs). During this COVID-19 epidemic, how to balance the risk of infected 2019-nCov and the risk of disability and teratogenesis of IMDs. Expert members of NBS extra quality assessment in National Clinical Center of Laboratory (NCCL) give a brief consensus for NBS of IMDs in the COVID-2019 epidemic, hoping that the brief consensus could be reference for NBS of IMDs in the other epidemic areas or periods all over the world.
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Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common X-linked enzymopathies caused by G6PD gene variant. We aimed to provide the characteristics of G6PD deficiency and G6PD gene variant distribution in a large Chinese newborn screening population. We investigated the prevalence of G6PD in China from 2013 to 2017. Then, we examined G6PD activity and G6PD gene in representative Chinese birth cohort to explore the distribution of G6PD gene variant in 2016. We then performed multicolor melting curve analysis to classify G6PD gene variants in 10,357 neonates with activity-confirmed G6PD deficiency, and DNA Sanger sequencing for G6PD coding exons if hot site variants were not found. The screened population, organizations, and provinces of G6PD deficiency were increased from 2013 to 2017 in China. The top five frequency of G6PD gene variants were c.1376G>T, c.1388G>A, c.95A>G, c.1024C>T, and c.871G>A and varied in different provinces, with regional and ethnic features, and four pathogenic variant sites (c.152C>T, c.290A>T, c.697G>C, and c.1285A>G) were first reported. G6PD deficiency mainly occurs in South China, and the frequency of G6PD gene variant varies in different regions and ethnicities.
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Variação Genética , Deficiência de Glucosefosfato Desidrogenase/epidemiologia , Deficiência de Glucosefosfato Desidrogenase/genética , Glucosefosfato Desidrogenase/genética , Triagem Neonatal , Alelos , China/epidemiologia , Mapeamento Cromossômico , Análise Mutacional de DNA/métodos , Feminino , Genes Ligados ao Cromossomo X , Glucosefosfato Desidrogenase/metabolismo , Deficiência de Glucosefosfato Desidrogenase/diagnóstico , Deficiência de Glucosefosfato Desidrogenase/história , História do Século XXI , Humanos , Incidência , Recém-Nascido , Masculino , Mutação , Triagem Neonatal/métodos , Triagem Neonatal/normas , Vigilância da PopulaçãoRESUMO
BACKGROUND: Previous studies indicated that miR-218 was deregulated in gastric cancer patients and correlated with tumor invasion and prognosis. The aim of this study was to clarify the effect of miR-218 on the malignant behavior of gastric cancer and its role in regulating Bmi-1/Akt signaling pathway. MATERIALS AND METHODS: We used miR-218 mimic to transfect gastric cancer cell lines AGS and SGC-7901, and the overexpression efficiency was validated using qRT-PCR assay. MTT assay and Transwell chamber system were performed to detect the effect of miR-218 on cell proliferation, invasion and migration on gastric cancer. Western blot and qRT-PCR assay was used to test the role of miR-218 in regulating Bmi-1/Akt signaling pathway. RESULTS: As shown in our research, ectopic expression of miR-218 in gastric cancer cells inhibits the proliferation, invasion and migration of gastric cancer cells. In addition, miR-218 re-expression inhibits the expression of Bmi-1 and its downstream target p-Akt473, as well as MMPs and EMT process. CONCLUSIONS: miR-218 inhibits the proliferation, invasion and migration of gastric cancer cells through modulating EMT process and the expression of MMPs via Bmi-1/Akt signaling pathway.
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Adenocarcinoma/genética , Carcinogênese/genética , Regulação Neoplásica da Expressão Gênica/genética , MicroRNAs/genética , Neoplasias Gástricas/genética , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Transição Epitelial-Mesenquimal/genética , Humanos , Estimativa de Kaplan-Meier , Complexo Repressor Polycomb 1/biossíntese , Proteínas Proto-Oncogênicas c-akt/biossíntese , Transdução de Sinais/genética , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/patologiaRESUMO
SIRT7 is an NAD+-dependent histone/non-histone deacetylase, which is highly expressed in different types of cancer including thyroid cancer; however, its biological function in thyroid cancer is still undiscovered. In this study, we found that SIRT7 expression was elevated in papillary thyroid cancers (PTCs), and demonstrated that SIRT7 knockdown dramatically inhibited the proliferation, colony formation, migration and invasion of thyroid cancer cells, and induced thyroid cancer cell cycle arrest and apoptosis. Conversely, SIRT7 re-expression markedly enhanced thyroid cancer cell growth, invasiveness and tumorigenic potential in nude mice. Further studies revealed that SIRT7 exerted an oncogenic function in thyroid tumorigenesis by phosphorylation of Akt and p70S6K1. Mechanistically, SIRT7 binds to the promoter of deleted in breast cancer-1 (DBC1), an endogenous inhibitor of SIRT1, and represses its transcription via deacetylation of H3K18Ac. This results in enhanced interactions between SIRT1 and Akt or p70S6K1, thereby promoting deacetylation and subsequent phosphorylation of Akt and p70S6K1 through a SIRT1-dependent manner. Altogether, our results show that DBC1 is a downstream target of SIRT7, and first uncover that SIRT7 promotes thyroid tumorigenesis through phosphorylation and activation of Akt and p70S6K1 via the modulation of DBC1/SIRT1 axis.
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Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Carcinoma Papilar/metabolismo , Proteínas de Neoplasias/fisiologia , Processamento de Proteína Pós-Traducional/fisiologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Sirtuína 1/metabolismo , Sirtuínas/fisiologia , Neoplasias da Glândula Tireoide/metabolismo , Acetilação , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Apoptose , Carcinoma Papilar/patologia , Ciclo Celular , Divisão Celular , Linhagem Celular Tumoral , Movimento Celular , Transformação Celular Neoplásica , Ativação Enzimática , Regulação Neoplásica da Expressão Gênica , Xenoenxertos , Camundongos , Camundongos Nus , Fosforilação , Ligação Proteica , Mapeamento de Interação de Proteínas , Transdução de Sinais , Neoplasias da Glândula Tireoide/patologia , Ensaio Tumoral de Célula-TroncoRESUMO
Clinical translation of therapeutic peptides, particularly those targeting intracellular protein-protein interactions (PPIs), has been hampered by their inefficacious cellular internalization in diseased tissue. Therapeutic peptides engineered into nanostructures with stable spatial architectures and smart disease targeting ability may provide a viable strategy to overcome the pharmaceutical obstacles of peptides. This study describes a strategy to assemble therapeutic peptides into a stable peptide-Au nanohybrid, followed by further self-assembling into higher-order nanoclusters with responsiveness to tumor microenvironment. As a proof of concept, an anticancer peptide termed ß-catenin/Bcl9 inhibitors is copolymerized with gold ion and assembled into a cluster of nanohybrids (pCluster). Through a battery of in vitro and in vivo tests, it is demonstrated that pClusters potently inhibit tumor growth and metastasis in several animal models through the impairment of the Wnt/ß-catenin pathway, while maintaining a highly favorable biosafety profile. In addition, it is also found that pClusters synergize with the PD1/PD-L1 checkpoint blockade immunotherapy. This new strategy of peptide delivery will likely have a broad impact on the development of peptide-derived therapeutic nanomedicine and reinvigorate efforts to discover peptide drugs that target intracellular PPIs in a great variety of human diseases, including cancer.
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The peptide-derived self-assembly platform has attracted increasing attention for its great potential to develop into multitargeting nanomedicines as well as its inherent biocompatibility and biodegradability. However, their clinical application potentials are often compromised by low stability, weak membrane penetrating ability, and limited functions. Herein, inspired by a natural protein from the seeds of Luffa cylindrica, we engineered via epitope grafting and structure design a hybrid peptide-based nanoplatform, termed Lupbin, which is capable of self-assembling into a stable superstructure and concurrently targeting multiple protein-protein interactions (PPIs) located in cytoplasm and nuclei. We showed that Lupbin can efficiently penetrate cell membrane, escape from early endosome-dependent degradation, and subsequently disassemble into free monomers with wide distribution in cytosol and nucleus. Importantly, Lupbin abrogated tumor growth and metastasis through concurrent blockade of the Wnt/ß-catenin signaling and reactivation of the p53 signaling, with a highly favorable in vivo biosafety profile. Our strategy expands the application of self-assembled nanomedicines into targeting intercellular PPIs, provides a potential nanoplatform with high stability for multitargeted cancer therapy, and likely reinvigorates the development of peptide-based therapeutics for the treatment of different human diseases including cancer.
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Antineoplásicos Fitogênicos/farmacologia , Luffa/química , Nanopartículas/química , Peptídeos/farmacologia , Proteínas de Plantas/metabolismo , Neoplasias Cutâneas/tratamento farmacológico , Animais , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/metabolismo , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Camundongos , Camundongos Endogâmicos C57BL , Nanomedicina , Peptídeos/química , Peptídeos/metabolismo , Proteínas de Plantas/química , Ligação Proteica/efeitos dos fármacos , Sementes/química , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologiaRESUMO
Peptide-tuned self-assembly of macromolecular agents (>500 Da) such as therapeutic peptides offers a strategy to improve the properties and biofunctions of degradable nanomaterials, but the tough requirement of macromolecular therapeutics delivery and a lack of understanding of peptide-based self-assembly design present high barriers for their applications. Herein, we developed a new strategy for nanoengineering macromolecular drugs by an elaborate peptide, termed PSP (VVVVVHHRGDC), capable of directly conjugating with cargo to be a PSP-cargo monomer as building block tending to self-assemble into a well-defined nanoshell with tumor-triggered shape and charge switch. As a proof of concept, conjugation PSP to a D-peptide activator of tumor suppressor p53 termed DPMI (1492.5 Da) generated hollow spheres ~80 nm in diameter named PSP-DPMI that disintegrated only in the acidic microenvironment of tumor tissues, followed by integrin-mediated cellular uptake of PSP-DPMI monomers. Importantly, PSP-based self-assembly successfully endowed the DPMI with long circulation time and high cancer-cell-specific intracellular accumulation. PSP-DPMI nanoshells potently inhibited tumor growth in vitro and in vivo by the p53 restoration, while maintaining a highly favorable in vivo safety profile. Out of conventional encapsulation and conjugation, our study showcases a clinically viable novel method to nanoengineer macromolecular agents such as peptide for anticancer therapy and provides a hazard-free alternative strategy for the theranostics delivery.
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The aim of this study was to investigate copy number of ErbB family members (including EGFR, HER2, HER3 and HER4) in a cohort of gliomas and benign meningiomas (control subjects), and explore the associations of their copy number with clinicopathological characteristics and clinical outcomes of glioma patients. Using real-time quantitative PCR assay, we demonstrated that copy number of EGFR, HER2, HER3 and HER4 in glioma patients was significantly increased compared to control subjects. Moreover, our data also showed that the risk of cancer-related death was positively associated with copy number gain (CNG) of EGFR, HER3 and HER4, but not HER2. CNG of EGFR and HER2 was positively related to radiotherapy, while CNG of HER3 and HER4 was negatively related to chemotherapy. Importantly, EGFR CNG significantly shortened median survival times of glioma patients regardless of gender, tumor grade and therapeutic regimens. Stratified analysis showed that CNG of HER2-4 almost did not influence the survival of male patients, patients with high-grade tumors and patients receiving chemotherapy, but dramatically shortened median survival times of female patients, those with low-grade tumors and those receiving radiotherapy. Collectively, our data not only demonstrate that the members of ErbB family are frequently amplified in gliomas, but also suggest that these common genetic events may be prognostic factors for poor clinical outcomes in glioma patients.
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BACKGROUND AND AIMS: Neurofibromatosis type I (NF1) is one of the most common neurocutaneous syndromes characterized by development of adult neurofibromas which is mainly made up of Schwann cells. The disease is generally accepted to be caused by inactivation mutation of Nf1 gene. And Nf1 deficiency had been reported to lead to ROS overproduction and epithelial-mesenchymal transition (EMT) phenotype. This study was designed to investigate whether excessive ROS conferred to Nf1 deficiency-induced EMT in Schwann cells. METHODS: Colony formation, wound healing assay and transwell assay was used to evaluate the effects of stable Nf1 knockdown in SW10 Schwann cells. Western blot and ROS assay was conducted to explore the molecular mechanisms of Nf1 inactivation in tumorigenesis. Animal experiments were performed to assess the inhibitory effects of lipoamide, which is the neutral amide of α-lipoic acid and functions as a potent antioxidant to scavenge ROS, on Nf1-deficiency tumor growth in vivo. RESULTS: Nf1 knockdown enhanced the cellular capacities of proliferation, migration and invasion, promoted ROS generation, decreased the expression of epithelial surface marker E-cadherin, and up-regulated several EMT-associated molecules in Schwann cells. Moreover, lipoamide dose-dependently inhibited not only Nf1 deficiency-induced EMT but also spontaneous EMT. Furthermore, lipoamide markedly suppresses tumor growth in a mouse model of NF1-associated neurofibroma. CONCLUSIONS: Our results clearly reveal that ROS overproduction is responsible for Nf1 deficiency-induced EMT and plays a crucial role in NF1 tumor growth. The findings presented herein shed light on the potential of antioxidant therapy to prevent the progression of NF1-associated neurofibroma.
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Transição Epitelial-Mesenquimal/efeitos dos fármacos , Genes da Neurofibromatose 1 , Neurofibroma/tratamento farmacológico , Neurofibromatose 1/tratamento farmacológico , Neurofibromina 1/deficiência , Espécies Reativas de Oxigênio/metabolismo , Células de Schwann/efeitos dos fármacos , Ácido Tióctico/análogos & derivados , Animais , Western Blotting , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Transformação Celular Neoplásica/patologia , Células Cultivadas , Masculino , Camundongos , Camundongos Nus , Ácido Tióctico/farmacologia , Regulação para Cima , Cicatrização/efeitos dos fármacosRESUMO
To date, the mechanisms underlying global downregulation of miRNAs in cancer remain largely unclear. Recent findings indicate that activated ERK can cause widespread miRNA repression through suppressing the major steps of miRNA biogenesis. Here we discuss how ERK signaling globally downregulates miRNAs and how this contributes to tumorigenesis.
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Carcinogênese/genética , Sistema de Sinalização das MAP Quinases/genética , MicroRNAs/genética , Neoplasias/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias/patologiaRESUMO
BRAFV600E mutation is frequently found in human cancers particularly thyroid cancer and melanoma, and is involved in the regulation of gene expression through activating MAPK/Erk signaling. Trimethylation of histone 3 lysine 27 (H3K27me3) is a critical epigenetic mark for the maintenance of gene silencing in tumorigenesis. However, molecular mechanism underlying the complex interplay between these two molecular events remains to be explored. In the present study, we conducted chromatin immunoprecipitation combined with next-generation sequencing (ChIP-Seq) and expression microarray analysis in NIH3T3 cells to explore the relationship between H3K27me3 and transcriptional regulation by BRAFV600E mutation. Our results showed that activated MAPK/Erk signaling by BRAFV600E mutation was a trigger of this epigenetic processing at many downstream target genes in cancer cell lines and BrafV600E-induced thyroid cancer of transgenetic mice. By integrating ChIP-Seq and gene expression microarray data, we identified 150 down-regulated loci with increased levels of H3K27me3 in BRAF-mutant cells relative to BRAF wild-type cells. Our data also demonstrated that c-Myc, a downstream key effector of BRAFV600E signaling, was required for BRAFV600E-induced changes in H3K27me3 through regulating the components of the polycomb repressive complex 2 (PRC2) genes Ezh2, Suz12 and Jarid2 at both transcriptional levels via direct binding to their regulatory elements and post-transcriptional levels via repressing the miR-26a, miR-200b and miR-155. In addition, BRAFV600E also caused gene silencing through Erk1/2-induced RNA polymerase II (RNAPII) poising and chromatin architecture. Collectively, our data uncover a previously unknown epigenetic mechanism in the tumorigenesis of BRAFV600E-driven cancers.