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Bamboo scrimber is acknowledged for its eco-friendly potential as a structural material. Its properties are significantly affected by both its density and resin content, but the effect of resin content on the properties under high density is not yet known. In this study, the microstructure, water resistance, mechanical properties, and thermal stability of bamboo scrimbers with varying resin content at a density of 1.30 g/cm3 were investigated. The results unearthed that phenolic resin assisted in the densification of bamboo cells during hot pressing, and a higher resin content could effectively reduce the cracks in the scrimber. The inherent cellulose I structure remained unaffected, but an increase in resin content led to a noticeable decline in crystallinity. Additionally, an increase in resin content pronouncedly improved the water resistance and dimensional stability of bamboo scrimbers. The water absorption and thickness swelling were as low as 9.67% and 7.62%, respectively. The modulus of rupture (MOR) exhibited a marginal increase with the amount of resin, whereas the compressive strength and short-beam shearing strength first increased and then decreased. Their peak strengths were 327.87 MPa at a resin content of 15 wt.%, and 168.85 MPa and 25.96 MPa at 11 wt.%, respectively. However, phenolic resin accelerated the thermal decomposition of bamboo scrimbers, and more resin worsened the thermal stability. These research outcomes offer a dual advantage, providing both a theoretical foundation and concrete data that can inform the production and practical application of high-density bamboo scrimbers.
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Aberrant expression of the Forkhead box transcription factor, FOXQ1, is a prevalent mechanism of epithelial-mesenchymal transition (EMT) and metastasis in multiple carcinoma types. However, it remains unknown how FOXQ1 regulates gene expression. Here, we report that FOXQ1 initiates EMT by recruiting the MLL/KMT2 histone methyltransferase complex as a transcriptional coactivator. We first establish that FOXQ1 promoter recognition precedes MLL complex assembly and histone-3 lysine-4 trimethylation within the promoter regions of critical genes in the EMT program. Mechanistically, we identify that the Forkhead box in FOXQ1 functions as a transactivation domain directly binding the MLL core complex subunit RbBP5 without interrupting FOXQ1 DNA binding activity. Moreover, genetic disruption of the FOXQ1-RbBP5 interaction or pharmacologic targeting of KMT2/MLL recruitment inhibits FOXQ1-dependent gene expression, EMT, and in vivo tumor progression. Our study suggests that targeting the FOXQ1-MLL epigenetic axis could be a promising strategy to combat triple-negative breast cancer metastatic progression.
Assuntos
Neoplasias da Mama , Segunda Neoplasia Primária , Feminino , Humanos , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal/fisiologia , Fatores de Transcrição Forkhead/metabolismo , Regulação Neoplásica da Expressão Gênica , Segunda Neoplasia Primária/genética , Proteína de Leucina Linfoide-Mieloide/metabolismo , Melanoma Maligno CutâneoRESUMO
The methyltransferase like 3 (METTL3) has been generally recognized as a nuclear protein bearing oncogenic properties. We find predominantly cytoplasmic METTL3 expression inversely correlates with node metastasis in human cancers. It remains unclear if nuclear METTL3 is functionally distinct from cytosolic METTL3 in driving tumorigenesis and, if any, how tumor cells sense oncogenic insults to coordinate METTL3 functions within these intracellular compartments. Here, we report an acetylation-dependent regulation of METTL3 localization that impacts on metastatic dissemination. We identify an IL-6-dependent positive feedback axis to facilitate nuclear METTL3 functions, eliciting breast cancer metastasis. IL-6, whose mRNA transcript is subjected to METTL3-mediated m6A modification, promotes METTL3 deacetylation and nuclear translocation, thereby inducing global m6A abundance. This deacetylation-mediated nuclear shift of METTL3 can be counterbalanced by SIRT1 inhibition, a process that is further enforced by aspirin treatment, leading to ablated lung metastasis via impaired m6A methylation. Intriguingly, acetylation-mimetic METTL3 mutant reconstitution results in enhanced translation and compromised metastatic potential. Our study identifies an acetylation-dependent regulatory mechanism determining the subcellular localization of METTL3, which may provide mechanistic clues for developing therapeutic strategies to combat breast cancer metastasis.
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Neoplasias da Mama , Metiltransferases , Humanos , Feminino , Metiltransferases/metabolismo , Acetilação , Sirtuína 1/metabolismo , Interleucina-6/metabolismo , RNA Mensageiro/metabolismo , Carcinogênese , Neoplasias da Mama/genética , Proteínas Nucleares/metabolismo , AspirinaRESUMO
Aging is a primary risk factor for neurodegenerative diseases, such as Alzheimer's disease (AD). SIRT2, an NAD+(nicotinamide adenine dinucleotide)-dependent deacetylase, accumulates in the aging brain. Here, we report that, in the amyloid precursor protein (APP)/PS1 transgenic mouse model of AD, genetic deletion of SIRT2 or pharmacological inhibition of SIRT2 ameliorates cognitive impairment. We find that suppression of SIRT2 enhances acetylation of APP, which promotes non-amyloidogenic processing of APP at the cell surface, leading to increased soluble APP-α (sAPPα). We discover that lysines 132 and 134 of the major pathogenic protein ß-amyloid (Aß) precursor are acetylated and that these residues are deacetylated by SIRT2. Strikingly, exogenous expression of wild-type or an acetylation-mimic APP mutant protects cultured primary neurons from Aß42 challenge. Our study identifies SIRT2-mediated deacetylation of APP on K132 and K134 as a regulated post-translational modification (PTM) and suggests inhibition of SIRT2 as a potential therapeutic strategy for AD.
Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Acetilação , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Modelos Animais de Doenças , Camundongos , Camundongos Transgênicos , Presenilina-1/metabolismo , Processamento de Proteína Pós-Traducional , Sirtuína 2/genética , Sirtuína 2/metabolismoRESUMO
Improper distribution of chromosomes during mitosis can contribute to malignant transformation. Higher eukaryotes have evolved a mitotic catastrophe mechanism for eliminating mitosis-incompetent cells; however, the signaling cascade and its epigenetic regulation are poorly understood. Our analyses of human cancerous tissue revealed that the NAD-dependent deacetylase SIRT2 is up-regulated in early-stage carcinomas of various organs. Mass spectrometry analysis revealed that SIRT2 interacts with and deacetylates the structural maintenance of chromosomes protein 1 (SMC1A), which then promotes SMC1A phosphorylation to properly drive mitosis. We have further demonstrated that inhibition of SIRT2 activity or continuously increasing SMC1A-K579 acetylation causes abnormal chromosome segregation, which, in turn, induces mitotic catastrophe in cancer cells and enhances their vulnerability to chemotherapeutic agents. These findings suggest that regulation of the SIRT2-SMC1A axis through deacetylation-phosphorylation permits escape from mitotic catastrophe, thus allowing early precursor lesions to overcome oncogenic stress.
Assuntos
Antimitóticos , Sirtuína 2 , Acetilação , Carcinogênese/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Epigênese Genética , Humanos , Fosforilação , Sirtuína 2/genética , Sirtuína 2/metabolismoRESUMO
Drug resistance and tumor recurrence are major challenges in cancer treatment. Cancer cells often display centrosome amplification. To maintain survival, cancer cells achieve bipolar division by clustering supernumerary centrosomes. Targeting centrosome clustering is therefore considered a promising therapeutic strategy. However, the regulatory mechanisms of centrosome clustering remain unclear. Here we report that KIFC1, a centrosome clustering regulator, is positively associated with tumor recurrence. Under DNA damaging treatments, the ATM and ATR kinases phosphorylate KIFC1 at Ser26 to selectively maintain the survival of cancer cells with amplified centrosomes via centrosome clustering, leading to drug resistance and tumor recurrence. Inhibition of KIFC1 phosphorylation represses centrosome clustering and tumor recurrence. This study identified KIFC1 as a prognostic tumor recurrence marker, and revealed that tumors can acquire therapeutic resistance and recurrence via triggering centrosome clustering under DNA damage stresses, suggesting that blocking KIFC1 phosphorylation may open a new vista for cancer therapy.
Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Centrossomo/metabolismo , Cinesinas/metabolismo , Recidiva Local de Neoplasia/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular Tumoral , Instabilidade Cromossômica , Dano ao DNA , Resistencia a Medicamentos Antineoplásicos , Humanos , Cinesinas/química , Camundongos , Recidiva Local de Neoplasia/patologia , Fosforilação , Fosfosserina/metabolismoRESUMO
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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A major challenge in chemotherapy is chemotherapy resistance in cells lacking p53. Here we demonstrate that NIP30, an inhibitor of the oncogenic REGγ-proteasome, attenuates cancer cell growth and sensitizes p53-compromised cells to chemotherapeutic agents. NIP30 acts by binding to REGγ via an evolutionarily-conserved serine-rich domain with 4-serine phosphorylation. We find the cyclin-dependent phosphatase CDC25A is a key regulator for NIP30 phosphorylation and modulation of REGγ activity during the cell cycle or after DNA damage. We validate CDC25A-NIP30-REGγ mediated regulation of the REGγ target protein p21 in vivo using p53-/- and p53/REGγ double-deficient mice. Moreover, Phosphor-NIP30 mimetics significantly increase the growth inhibitory effect of chemotherapeutic agents in vitro and in vivo. Given that NIP30 is frequently mutated in the TCGA cancer database, our results provide insight into the regulatory pathway controlling the REGγ-proteasome in carcinogenesis and offer a novel approach to drug-resistant cancer therapy.
Assuntos
Autoantígenos/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Nucleares/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/metabolismo , Proteína Supressora de Tumor p53/deficiência , Animais , Autoantígenos/genética , Ciclo Celular , Linhagem Celular Tumoral , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Resistencia a Medicamentos Antineoplásicos , Células HEK293 , Xenoenxertos , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Camundongos , Camundongos Knockout , Proteínas Nucleares/genética , Fosforilação , Complexo de Endopeptidases do Proteassoma/deficiência , Complexo de Endopeptidases do Proteassoma/genética , Proteína Supressora de Tumor p53/genética , Fosfatases cdc25/metabolismoRESUMO
Ubiquitin-specific peptidase 10 (USP10) stabilizes both tumor suppressors and oncogenes in a context-dependent manner. However, the nature of USP10's role in non-small cell lung cancer (NSCLC) remains unclear. By analyzing The Cancer Genome Atlas (TCGA) database, we have shown that high levels of USP10 are associated with poor overall survival in NSCLC with mutant p53, but not with wild-type p53. Consistently, genetic depletion or pharmacological inhibition of USP10 dramatically reduces the growth of lung cancer xenografts lacking wild-type p53 and sensitizes them to cisplatin. Mechanistically, USP10 interacts with, deubiquitinates, and stabilizes oncogenic protein histone deacetylase 6 (HDAC6). Furthermore, reintroducing either USP10 or HDAC6 into a USP10-knockdown NSCLC H1299 cell line with null-p53 renders cisplatin resistance. This result suggests the existence of a "USP10-HDAC6-cisplatin resistance" axis. Clinically, we have found a positive correlation between USP10 and HDAC6 expression in a cohort of NSCLC patient samples. Moreover, we have shown that high levels of USP10 mRNA correlate with poor overall survival in a cohort of advanced NSCLC patients who received platinum-based chemotherapy. Overall, our studies suggest that USP10 could be a potential biomarker for predicting patient response to platinum, and that targeting USP10 could sensitize lung cancer patients lacking wild-type p53 to platinum-based therapy.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Cisplatino/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Desacetilase 6 de Histona/metabolismo , Neoplasias Pulmonares/tratamento farmacológico , Proteína Supressora de Tumor p53/deficiência , Ubiquitina Tiolesterase/metabolismo , Animais , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Cisplatino/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Camundongos SCID , Mutação/genética , Neoplasias Ovarianas/patologia , Platina/farmacologia , Ligação Proteica/efeitos dos fármacos , Estabilidade Proteica/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Especificidade por Substrato/efeitos dos fármacos , Proteína Supressora de Tumor p53/metabolismo , Ubiquitinação/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The homeostatic link between oxidative stress and autophagy plays an important role in cellular responses to a wide variety of physiological and pathological conditions. However, the regulatory pathway and outcomes remain incompletely understood. Here, we show that reactive oxygen species (ROS) function as signaling molecules that regulate autophagy through ataxia-telangiectasia mutated (ATM) and cell cycle checkpoint kinase 2 (CHK2), a DNA damage response (DDR) pathway activated during metabolic and hypoxic stress. We report that CHK2 binds to and phosphorylates Beclin 1 at Ser90/Ser93, thereby impairing Beclin 1-Bcl-2 autophagy-regulatory complex formation in a ROS-dependent fashion. We further demonstrate that CHK2-mediated autophagy has an unexpected role in reducing ROS levels via the removal of damaged mitochondria, which is required for cell survival under stress conditions. Finally, CHK2-/- mice display aggravated infarct phenotypes and reduced Beclin 1 p-Ser90/Ser93 in a cerebral stroke model, suggesting an in vivo role of CHK2-induced autophagy in cell survival. Taken together, these results indicate that the ROS-ATM-CHK2-Beclin 1-autophagy axis serves as a physiological adaptation pathway that protects cells exposed to pathological conditions from stress-induced tissue damage.
Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteína Beclina-1/metabolismo , Quinase do Ponto de Checagem 2/metabolismo , AVC Isquêmico/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Animais , Autofagia , Linhagem Celular , Modelos Animais de Doenças , Células HCT116 , Células HEK293 , Células HeLa , Humanos , Camundongos , Estresse Oxidativo , FosforilaçãoRESUMO
Sirt3, as a major mitochondrial nicotinamide adenine dinucleotide (NAD)-dependent deacetylase, is required for mitochondrial metabolic adaption to various stresses. However, how to regulate Sirt3 activity responding to metabolic stress remains largely unknown. Here, we report Sirt3 as a SUMOylated protein in mitochondria. SUMOylation suppresses Sirt3 catalytic activity. SUMOylation-deficient Sirt3 shows elevated deacetylation on mitochondrial proteins and increased fatty acid oxidation. During fasting, SUMO-specific protease SENP1 is accumulated in mitochondria and quickly de-SUMOylates and activates Sirt3. SENP1 deficiency results in hyper-SUMOylation of Sirt3 and hyper-acetylation of mitochondrial proteins, which reduces mitochondrial metabolic adaption responding to fasting. Furthermore, we find that fasting induces SENP1 translocation into mitochondria to activate Sirt3. The studies on mice show that Sirt3 SUMOylation mutation reduces fat mass and antagonizes high-fat diet (HFD)-induced obesity via increasing oxidative phosphorylation and energy expenditure. Our results reveal that SENP1-Sirt3 signaling modulates Sirt3 activation and mitochondrial metabolism during metabolic stress.
Assuntos
Cisteína Endopeptidases/metabolismo , Mitocôndrias/metabolismo , Mutação , Obesidade/metabolismo , Transdução de Sinais , Sirtuína 3/metabolismo , Sumoilação , Acetilação , Animais , Cisteína Endopeptidases/genética , Gorduras na Dieta/efeitos adversos , Gorduras na Dieta/farmacologia , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Mutantes , Mitocôndrias/genética , Mitocôndrias/patologia , Obesidade/induzido quimicamente , Obesidade/genética , Obesidade/patologia , Sirtuína 3/genéticaRESUMO
Tumor repopulation during therapy is an important cause of treatment failure. Strategies to overcome repopulation are arising in parallel with advances in the comprehension of underlying biological mechanisms. Here, we reveal a new mechanism by which high mobility group box 1 (HMGB1) released by dying cells during radiotherapy or chemotherapy could stimulate living tumor cell proliferationInhibition or genetic ablation of HMGB1 suppressed tumor cell proliferation. This effect was due to binding of HMGB1with the member receptor for advanced glycation end-products (RAGE), which activated downstream ERK and p38 signaling pathway and promoted cell proliferation. Furthermore, higher HMGB1 expression in tumor tissue correlated with poor overall survival and higher HMGB1 concentration was detected in serum of patients who accepted radiotherapy. Collectively, the results from this study suggested that interaction between dead cells and surviving cells might influence the fate of tumor. HMGB1 could be a novel tumor promoter with therapeutic and prognostic relevance in cancers.
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Proteína HMGB1/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Comunicação Parácrina/efeitos da radiação , Antígenos de Neoplasias/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos da radiação , Sobrevivência Celular/efeitos da radiação , Feminino , Humanos , Sistema de Sinalização das MAP Quinases/efeitos da radiação , Masculino , Pessoa de Meia-Idade , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Análise Multivariada , Prognóstico , Ligação Proteica , Análise de SobrevidaRESUMO
Most eukaryotic mRNAs are polyadenylated in the nucleus, and the poly(A)-tail is required for efficient mRNA export and translation. However, mechanisms governing mRNA transport remain unclear. Here, we report that the nicotinamide adenine dinucleotide (NAD)-dependent deacetylase SIRT1 acts as an energy sensor and negatively regulates poly(A)RNA transport via deacetylating a poly(A)-binding protein, PABP1. Upon energy starvation, SIRT1 interacts with and deacetylates PABP1 and deactivates its poly(A)RNA binding, leading to nuclear accumulation of PABP1 and poly(A)RNA and thus facilitating eukaryotic cells to attenuate protein synthesis and energy consumption to adapt to energy stress. Moreover, AMPK-directed SIRT1 phosphorylation is required for energy starvation-induced PABP1-SIRT1 association, PABP1 deacetylation, and poly(A)RNA nuclear retention. In addition, the SIRT1-PABP1 association is not specific to energy starvation but represents a common stress response. These observations provide insights into dynamic modulation of eukaryotic mRNA transport and translation, suggesting that the poly(A)-tail also provides a basis for eukaryotes to effectively shut down mature mRNA transport and thereby tailor protein synthesis to maintain energy homeostasis under stress conditions.
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Proteína I de Ligação a Poli(A)/genética , Transporte de RNA , Sirtuína 1/genética , Animais , Células HeLa , Humanos , Camundongos , Camundongos Knockout , Proteína I de Ligação a Poli(A)/metabolismo , Sirtuína 1/metabolismoRESUMO
Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) has been an important afforestation species in northeast China. It has obvious defects of buckling and cracking easily, which are caused by its chemical components. Trametes versicolor (L.) Lloyd, a white-rot fungus, can decompose the cellulose, hemicellulose, and lignin in the wood. White-rot fungus was used to biologically degrade Chinese fir wood. The effects of different degradation time on the Chinese fir wood's mechanical properties, micromorphology, chemical components, and crystallinity were studied. The results showed that the heartwood of Chinese fir was more durable than the sapwood and the durability class of Chinese fir was III. Trametes versicolor (L.) Lloyd had a greater influence on the mechanical properties (especially with respect to the modulus of elasticity (MOE)) for the sapwood. Trametes versicolor (L.) Lloyd degraded Chinese fir and colonized the lumen of various wood cell types in Chinese fir, penetrated cell walls via pits, caused erosion troughs and bore holes, and removed all cell layers. The ability of white-rot fungus to change the chemical composition mass fraction for Chinese fir was: hemicellulose > lignin > cellulose. The durability of the chemical compositions was: lignin > cellulose > hemicellulose. The crystallinity of the cellulose decreased and the mean size of the ordered (crystalline) domains increased after being treated by white-rot fungus.
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In mammalian cells, histone deacetylase (HDAC) and Sirtuin (SIRT) are two families responsible for removing acetyl groups from acetylated proteins. Here, we describe protein deacetylation coupled with deacetylimination as a function of lysyl oxidase (LOX) family members. LOX-like 3 (Loxl3) associates with Stat3 in the nucleus to deacetylate and deacetyliminate Stat3 on multiple acetyl-lysine sites. Surprisingly, Loxl3 N-terminal scavenger receptor cysteine-rich (SRCR) repeats, rather than the C-terminal oxidase catalytic domain, represent the major deacetylase/deacetyliminase activity. Loxl3-mediated deacetylation/deacetylimination disrupts Stat3 dimerization, abolishes Stat3 transcription activity, and restricts cell proliferation. In Loxl3-/- mice, Stat3 is constitutively acetylated and naive CD4+ T cells are potentiated in Th17/Treg cell differentiation. When overexpressed, the SRCR repeats from other LOX family members can catalyze protein deacetylation/deacetylimination. Thus, our findings delineate a hitherto-unknown mechanism of protein deacetylation and deacetylimination catalyzed by lysyl oxidases.
Assuntos
Aminoácido Oxirredutases/metabolismo , Linfócitos T CD4-Positivos/enzimologia , Colite/enzimologia , Processamento de Proteína Pós-Traducional , Fator de Transcrição STAT3/metabolismo , Acetilação , Aminoácido Oxirredutases/deficiência , Aminoácido Oxirredutases/genética , Animais , Linfócitos T CD4-Positivos/imunologia , Catálise , Diferenciação Celular , Núcleo Celular/enzimologia , Proliferação de Células , Colite/genética , Colite/imunologia , Modelos Animais de Doenças , Genótipo , Células HEK293 , Células HeLa , Humanos , Células MCF-7 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , Domínios Proteicos , Multimerização Proteica , Interferência de RNA , Fator de Transcrição STAT3/genética , Linfócitos T Reguladores/enzimologia , Linfócitos T Reguladores/imunologia , Células Th17/enzimologia , Células Th17/imunologia , Transcrição Gênica , TransfecçãoRESUMO
Maintenance of energy homeostasis is essential for cell survival. Here, we report that the ATP- and ubiquitin-independent REGγ-proteasome system plays a role in maintaining energy homeostasis and cell survival during energy starvation via repressing rDNA transcription, a major intracellular energy-consuming process. Mechanistically, REGγ-proteasome limits cellular rDNA transcription and energy consumption by targeting the rDNA transcription activator SirT7 for ubiquitin-independent degradation under normal conditions. Moreover, energy starvation induces an AMPK-directed SirT7 phosphorylation and subsequent REGγ-dependent SirT7 subcellular redistribution and degradation, thereby further reducing rDNA transcription to save energy to overcome cell death. Energy starvation is a promising strategy for cancer therapy. Our report also shows that REGγ knockdown markedly improves the anti-tumour activity of energy metabolism inhibitors in mice. Our results underscore a control mechanism for an ubiquitin-independent process in maintaining energy homeostasis and cell viability under starvation conditions, suggesting that REGγ-proteasome inhibition has a potential to provide tumour-starving benefits.
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Autoantígenos/metabolismo , Homeostase , Neoplasias/terapia , Complexo de Endopeptidases do Proteassoma/metabolismo , Animais , Sobrevivência Celular , Citoplasma/metabolismo , DNA Ribossômico/metabolismo , Células HCT116 , Células HEK293 , Células HeLa , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Camundongos Nus , Fosforilação , Ubiquitina/metabolismoRESUMO
BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is the sixth most lethal cancer worldwide and the fourth most lethal cancer in China. Genomic characterization of tumors, particularly those of different stages, is likely to reveal additional oncogenic mechanisms. Although copy number alterations and somatic point mutations associated with the development of ESCC have been identified by array-based technologies and genome-wide studies, the genomic characterization of ESCCs from different stages of the disease has not been explored. Here, we have performed either whole-genome sequencing or whole-exome sequencing on 51 stage I and 53 stage III ESCC patients to characterize the genomic alterations that occur during the various clinical stages of ESCC, and further validated these changes in 36 atypical hyperplasia samples. RESULTS: Recurrent somatic amplifications at 8q were found to be enriched in stage I tumors and the deletions of 4p-q and 5q were particularly identified in stage III tumors. In particular, the FAM84B gene was amplified and overexpressed in preclinical and ESCC tumors. Knockdown of FAM84B in ESCC cell lines significantly reduced in vitro cell growth, migration and invasion. Although the cancer-associated genes TP53, PIK3CA, CDKN2A and their pathways showed no significant difference between stage I and stage III tumors, we identified and validated a prevalence of mutations in NOTCH1 and in the NOTCH pathway that indicate that they are involved in the preclinical and early stages of ESCC. CONCLUSIONS: Our results suggest that FAM84B and the NOTCH pathway are involved in the progression of ESCC and may be potential diagnostic targets for ESCC susceptibility.
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Carcinoma de Células Escamosas/genética , Neoplasias Esofágicas/genética , Genoma Humano/genética , Proteínas de Neoplasias/genética , Receptores Notch/genética , Análise de Sequência de DNA/métodos , Transdução de Sinais/genética , Adulto , Idoso , Linhagem Celular Tumoral , Movimento Celular/genética , Deleção Cromossômica , Variações do Número de Cópias de DNA , Progressão da Doença , Neoplasias Esofágicas/patologia , Predisposição Genética para Doença/genética , Humanos , Imuno-Histoquímica , Hibridização in Situ Fluorescente , Masculino , Proteínas de Membrana , Pessoa de Meia-Idade , Mutação , Proteínas de Neoplasias/metabolismo , Estadiamento de Neoplasias , Lesões Pré-Cancerosas/genética , Interferência de RNARESUMO
AIMS: Parkinson's disease (PD) heavily affects humans and little is known about its cause and pathogenesis. Sirtuin 3 (Sirt3) plays a key role in regulating mitochondrial dysfunction, which is the main cause of DAergic neuronal loss in PD. We investigated the mechanisms of neuroprotective role of Sirt3 in DAergic neuronal survival. RESULTS: Sirt3 was reduced in 1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine (MPTP)-treated neurons with its overexpression being neuroprotective. We identified that Sirt3 interacted with manganese superoxide dismutase (SOD2) and adenosine triphosphate (ATP) synthase ß and modulated their activities by deacetylating SOD2 (K130) and ATP synthase ß (K485) to prevent reactive oxygen species accumulation and ATP depletion, and to alleviate DAergic neuronal death upon MPTP treatment. Peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) interacted with estrogen-related receptor alpha (ERRα) that bound to the Sirt3 promoter as its transcription factor to regulate Sirt3 expression and DAergic neuronal death. In the mouse midbrain, MPTP administration led to the loss of PGC-1α and Sirt3, high acetylation level of SOD2 and ATP synthase ß, and the specific loss of DAergic neurons, while Sirt3 overexpression could protect against DAergic neuronal loss. Sirt3 knockout mice exhibited more sensitive and more DAergic neuronal loss to MPTP treatment. INNOVATION: The study provides new insights into a critical PGC-1α/ERRα-Sirt3 pathway, linking regulation of mitochondrial protein acetylation and DAergic neuronal death in PD pathogenesis, which provide a potential therapeutic strategy and target in PD treatment. CONCLUSION: These results provide a vital PGC-1α/ERRα-Sirt3 pathway that protects against DAergic neuronal death by directly deacetylating SOD2 (K130) and ATP synthase ß (K485) in PD.
Assuntos
Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Receptores de Estrogênio/metabolismo , Sirtuína 3/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Western Blotting , Morte Celular/genética , Morte Celular/fisiologia , Imunoprecipitação da Cromatina , Células HEK293 , Humanos , Imuno-Histoquímica , Imunoprecipitação , Lentivirus/genética , Camundongos , Mitocôndrias/metabolismo , ATPases Mitocondriais Próton-Translocadoras/genética , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Modelos Biológicos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Receptores de Estrogênio/genética , Sirtuína 3/genética , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo , Receptor ERRalfa Relacionado ao EstrogênioRESUMO
BACKGROUND: Recurrent genetic abnormalities that correlate with clinical features could be used to determine patients' prognosis, select treatments and predict responses to therapy. Esophageal squamous cell carcinoma (ESCC) contains genomic alterations of undefined clinical significance. We aimed to identify mutually exclusive mutations that are frequently detected in ESCCs and characterized their associations with clinical variables. METHODS: We analyzed next-generation-sequencing data from 104 ESCCs from Taihang Mountain region of China; 96 pairs were selected for deep target-capture-based validation and analysis of clinical and pathology data. We used model proposed by Szczurek to identify exclusive mutations and to associate these with pathology findings. Univariate and multivariate analyses with Cox proportional hazards model were used to examine the association between mutations and overall survival and response to chemotherapy. Findings were validated in an analysis of samples from 89 patients with ESCC from Taihang Mountain. RESULTS: We identified statistically significant mutual exclusivity between mutations in NOTCH1 and PIK3CA in ESCC samples. Mutations in NOTCH1 were associated with well-differentiated, early-stage malignancy and less metastasis to regional lymph nodes. Nonetheless, patients with NOTCH1 mutations had shorter survival times than patients without NOTCH1 mutations, and failed to respond to chemotherapy. In contrast, patients with mutations in PIK3CA had better responses to chemotherapy and longer survival times than patients without PIK3CA mutations. CONCLUSIONS: In a genetic analysis of ESCCs from patients in China, we identified mutually exclusive mutations in NOTCH1 and PIK3CA. These findings might increase our understanding of ESCC development and be used as prognostic factors.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma de Células Escamosas/secundário , Neoplasias Esofágicas/patologia , Mutação/genética , Recidiva Local de Neoplasia/patologia , Fosfatidilinositol 3-Quinases/genética , Receptor Notch1/genética , Idoso , Apoptose/efeitos dos fármacos , Biomarcadores Tumorais/genética , Western Blotting , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/genética , Proliferação de Células/efeitos dos fármacos , China , Cisplatino/administração & dosagem , Classe I de Fosfatidilinositol 3-Quinases , Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Esofágicas/genética , Feminino , Fluoruracila/administração & dosagem , Seguimentos , Genômica/métodos , Humanos , Técnicas Imunoenzimáticas , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Invasividade Neoplásica , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/genética , Estadiamento de Neoplasias , Paclitaxel/administração & dosagem , Prognóstico , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Taxa de Sobrevida , Células Tumorais CultivadasRESUMO
Centrosome amplification is frequent in cancer, but the underlying mechanisms remain unclear. Here we report that disruption of the Kruppel-like factor 14 (KLF14) gene in mice causes centrosome amplification, aneuploidy and spontaneous tumorigenesis. Molecularly, KLF14 functions as a transcriptional repressor of Plk4, a polo-like kinase whose overexpression induces centrosome overduplication. Transient knockdown of KLF14 is sufficient to induce Plk4-directed centrosome amplification. Clinically, KLF14 transcription is significantly downregulated, whereas Plk4 transcription is upregulated in multiple types of cancers, and there exists an inverse correlation between KLF14 and Plk4 protein expression in human breast and colon cancers. Moreover, KLF14 depletion promotes AOM/DSS-induced colon tumorigenesis. Our findings reveal that KLF14 reduction serves as a mechanism leading to centrosome amplification and tumorigenesis. On the other hand, forced expression of KLF14 leads to mitotic catastrophe. Collectively, our findings identify KLF14 as a tumour suppressor and highlight its potential as biomarker and therapeutic target for cancer.