RESUMO
Cellular senescence is a terminal cell fate characterized by growth arrest and a metabolically active state characterized by high glycolytic activity. Human fibroblasts were placed in a unique metabolic state using a combination of methionine restriction (MetR) and rapamycin (Rapa). This combination induced a metabolic reprogramming that prevented the glycolytic shift associated with senescence. Surprisingly, cells treated in this manner did not undergo senescence but continued to divide at a slow rate even at high passage, in contrast with either Rapa treatment or MetR, both of which extended life span but eventually resulted in growth arrest. Transcriptome-wide analysis revealed a coordinated regulation of metabolic enzymes related to one-carbon metabolism including three methyltransferase enzymes (KMT2D, SETD1B, and ASH1L), key enzymes for both carnitine synthesis and histone modification. These enzymes appear to be involved in both the metabolic phenotype of senescent cells and the chromatin changes required for establishing the senescence arrest. Targeting one of these enzymes, ASH1L, produced both a glycolytic shift and senescence, providing proof of concept. These findings reveal a mechanistic link between a major metabolic hallmark of senescence and nuclear events required for senescence.
Assuntos
Senescência Celular , Epigênese Genética , Senescência Celular/genética , Fibroblastos/metabolismo , Glicólise , Metionina/metabolismo , Sirolimo/farmacologiaRESUMO
Innate immune responses of the earthworm Eisenia hortensis were studied by detecting mitochondrial membrane depolarization and reactive oxygen species (ROS) production after incubation with pathogen-associated molecular patterns (PAMPs). Coelomocytes from E. hortensis were incubated with zymosan, flagellin, or peptidoglycan (PTG) for 48 h in vitro and studied using flow cytometric assays for changes in mitochondrial membrane potential (ΔΨ(m)) or ROS production using the fluorescent indicators JC-1 or DHR 123, respectively. All three PAMPs evoked ΔΨ(m), with zymosan inducing the most significant membrane depolarization in coelomocyte samples compared to untreated controls. When treated with zymosan or flagellin, coelomocyte samples exhibited significant increases in ROS production in the zymosan sample after 16 h of in vitro incubation, but this effect was not observed for flagellin. These results demonstrate that PAMPs evoke evolutionarily conserved cellular responses which may be important during innate immune defenses to eradicate intracellular reserves of foreign pathogens.
Assuntos
Eimeria/microbiologia , Interações Hospedeiro-Patógeno , Potencial da Membrana Mitocondrial/imunologia , Membranas Mitocondriais/imunologia , Animais , Apoptose/efeitos dos fármacos , Eimeria/citologia , Eimeria/imunologia , Enterócitos/efeitos dos fármacos , Enterócitos/imunologia , Enterócitos/patologia , Flagelina/farmacologia , Imunidade Inata/efeitos dos fármacos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Membranas Mitocondriais/efeitos dos fármacos , Membranas Mitocondriais/microbiologia , Peptidoglicano/farmacologia , Espécies Reativas de Oxigênio , Zimosan/farmacologiaRESUMO
Methyltransferase-like 3 (METTL3) and 14 (METTL14) are core subunits of the methyltransferase complex that catalyses messenger RNA N6-methyladenosine (m6A) modification. Despite the expanding list of m6A-dependent functions of the methyltransferase complex, the m6A-independent function of the METTL3 and METTL14 complex remains poorly understood. Here we show that genome-wide redistribution of METTL3 and METTL14 transcriptionally drives the senescence-associated secretory phenotype (SASP) in an m6A-independent manner. METTL14 is redistributed to the enhancers, whereas METTL3 is localized to the pre-existing NF-κB sites within the promoters of SASP genes during senescence. METTL3 and METTL14 are necessary for SASP. However, SASP is not regulated by m6A mRNA modification. METTL3 and METTL14 are required for both the tumour-promoting and immune-surveillance functions of senescent cells, which are mediated by SASP in vivo in mouse models. In summary, our results report an m6A-independent function of the METTL3 and METTL14 complex in transcriptionally promoting SASP during senescence.
Assuntos
Envelhecimento/genética , Senescência Celular/genética , Metiltransferases/genética , Adenosina/análogos & derivados , Adenosina/genética , Animais , Metilação de DNA/genética , Genoma/genética , Camundongos , NF-kappa B/genética , RNA Mensageiro/genéticaRESUMO
The SWI/SNF chromatin-remodeling complex is frequently altered in human cancers. For example, the SWI/SNF component ARID1A is mutated in more than 50% of ovarian clear cell carcinomas (OCCC), for which effective treatments are lacking. Here, we report that ARID1A transcriptionally represses the IRE1α-XBP1 axis of the endoplasmic reticulum (ER) stress response, which confers sensitivity to inhibition of the IRE1α-XBP1 pathway in ARID1A-mutant OCCC. ARID1A mutational status correlated with response to inhibition of the IRE1α-XBP1 pathway. In a conditional Arid1aflox/flox/Pik3caH1047R genetic mouse model, Xbp1 knockout significantly improved survival of mice bearing OCCCs. Furthermore, the IRE1α inhibitor B-I09 suppressed the growth of ARID1A-inactivated OCCCs in vivo in orthotopic xenograft, patient-derived xenograft, and the genetic mouse models. Finally, B-I09 synergized with inhibition of HDAC6, a known regulator of the ER stress response, in suppressing the growth of ARID1A-inactivated OCCCs. These studies define the IRE1α-XBP1 axis of the ER stress response as a targetable vulnerability for ARID1A-mutant OCCCs, revealing a promising therapeutic approach for treating ARID1A-mutant ovarian cancers. SIGNIFICANCE: These findings indicate that pharmacological inhibition of the IRE1α-XBP1 pathway alone or in combination with HDAC6 inhibition represents an urgently needed therapeutic strategy for ARID1A-mutant ovarian cancers.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Proteínas de Ligação a DNA/genética , Estresse do Retículo Endoplasmático , Endorribonucleases/antagonistas & inibidores , Mutação , Neoplasias Ovarianas/patologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Fatores de Transcrição/genética , Proteína 1 de Ligação a X-Box/antagonistas & inibidores , Adenocarcinoma de Células Claras/tratamento farmacológico , Adenocarcinoma de Células Claras/genética , Adenocarcinoma de Células Claras/metabolismo , Adenocarcinoma de Células Claras/patologia , Animais , Apoptose , Proliferação de Células , Proteínas de Ligação a DNA/fisiologia , Endorribonucleases/genética , Endorribonucleases/metabolismo , Endorribonucleases/fisiologia , Feminino , Regulação Neoplásica da Expressão Gênica , Desacetilase 6 de Histona/antagonistas & inibidores , Inibidores de Histona Desacetilases/farmacologia , Humanos , Camundongos , Camundongos Knockout , Camundongos Nus , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/fisiologia , Fatores de Transcrição/fisiologia , Células Tumorais Cultivadas , Proteína 1 de Ligação a X-Box/genética , Proteína 1 de Ligação a X-Box/metabolismo , Proteína 1 de Ligação a X-Box/fisiologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Alterations in components of the SWI/SNF chromatin-remodeling complex occur in ~20% of all human cancers. For example, ARID1A is mutated in up to 62% of clear cell ovarian carcinoma (OCCC), a disease currently lacking effective therapies. Here we show that ARID1A mutation creates a dependence on glutamine metabolism. SWI/SNF represses glutaminase (GLS1) and ARID1A inactivation upregulates GLS1. ARID1A inactivation increases glutamine utilization and metabolism through the tricarboxylic acid cycle to support aspartate synthesis. Indeed, glutaminase inhibitor CB-839 suppresses the growth of ARID1A mutant, but not wildtype, OCCCs in both orthotopic and patient-derived xenografts. In addition, glutaminase inhibitor CB-839 synergizes with immune checkpoint blockade anti-PDL1 antibody in a genetic OCCC mouse model driven by conditional Arid1a inactivation. Our data indicate that pharmacological inhibition of glutaminase alone or in combination with immune checkpoint blockade represents an effective therapeutic strategy for cancers involving alterations in the SWI/SNF complex such as ARID1A mutations.
Assuntos
Adenocarcinoma de Células Claras , Neoplasias Ovarianas , Adenocarcinoma de Células Claras/tratamento farmacológico , Animais , Proteínas de Ligação a DNA/genética , Feminino , Glutaminase/genética , Glutamina/uso terapêutico , Humanos , Inibidores de Checkpoint Imunológico , Camundongos , Proteínas Nucleares/genética , Neoplasias Ovarianas/tratamento farmacológico , Fatores de Transcrição/genéticaRESUMO
We have recently discovered that AT-rich interactive domain-containing protein 1A (ARID1A) protects telomere cohesion through regulation of the cohesin subunit stromal antigen 1 (STAG1). ARID1A inactivation results in mitotic defects and negatively selects gross chromosomal aberrations, resulting in preservation of genomic stability in ARID1A-mutated cancers. These findings explain the long-standing paradox between mitotic defects caused by ARID1A inactivation and the lack of genomic instability in ARID1A-mutated cancers.
RESUMO
Epithelial ovarian cancer (EOC) is the most lethal of gynecologic malignancies. The standard-of-care treatment for EOC is platinum-based chemotherapy such as cisplatin. Platinum-based chemotherapy induces cellular senescence. Notably, therapy-induced senescence contributes to chemoresistance by inducing cancer stem-like cells (CSC). However, therapeutic approaches targeting senescence-associated CSCs remain to be explored. Here, we show that nicotinamide phosphoribosyltransferase (NAMPT) inhibition suppresses senescence-associated CSCs induced by platinum-based chemotherapy in EOC. Clinically applicable NAMPT inhibitors suppressed the outgrowth of cisplatin-treated EOC cells both in vitro and in vivo. Moreover, a combination of the NAMPT inhibitor FK866 and cisplatin improved the survival of EOC-bearing mice. These phenotypes correlated with inhibition of the CSCs signature, which consists of elevated expression of ALDH1A1 and stem-related genes, high aldehyde dehydrogenase activity, and CD133 positivity. Mechanistically, NAMPT regulates EOC CSCs in a paracrine manner through the senescence-associated secretory phenotype. Our results suggest that targeting NAMPT using clinically applicable NAMPT inhibitors, such as FK866, in conjunction with platinum-based chemotherapy represents a promising therapeutic strategy by suppressing therapy-induced senescence-associated CSCs. SIGNIFICANCE: This study highlights the importance of NAMPT-mediated NAD+ biosynthesis in the production of cisplatin-induced senescence-associated cancer stem cells, as well as tumor relapse after cisplatin treatment.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Carcinoma Epitelial do Ovário/tratamento farmacológico , Citocinas/antagonistas & inibidores , Células-Tronco Neoplásicas/efeitos dos fármacos , Nicotinamida Fosforribosiltransferase/antagonistas & inibidores , Neoplasias Ovarianas/tratamento farmacológico , Acrilamidas/farmacologia , Acrilamidas/uso terapêutico , Família Aldeído Desidrogenase 1/metabolismo , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Epitelial do Ovário/patologia , Linhagem Celular Tumoral , Senescência Celular/efeitos dos fármacos , Cisplatino/farmacologia , Cisplatino/uso terapêutico , Citocinas/metabolismo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Feminino , Humanos , Camundongos , Células-Tronco Neoplásicas/patologia , Nicotinamida Fosforribosiltransferase/metabolismo , Neoplasias Ovarianas/patologia , Piperidinas/farmacologia , Piperidinas/uso terapêutico , Retinal Desidrogenase/metabolismo , Esferoides Celulares , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Cyclic cGMP-AMP synthase (cGAS) is a pattern recognition cytosolic DNA sensor that is essential for cellular senescence. cGAS promotes inflammatory senescence-associated secretory phenotype (SASP) through recognizing cytoplasmic chromatin during senescence. cGAS-mediated inflammation is essential for the antitumor effects of immune checkpoint blockade. However, the mechanism by which cGAS recognizes cytoplasmic chromatin is unknown. Here we show that topoisomerase 1-DNA covalent cleavage complex (TOP1cc) is both necessary and sufficient for cGAS-mediated cytoplasmic chromatin recognition and SASP during senescence. TOP1cc localizes to cytoplasmic chromatin and TOP1 interacts with cGAS to enhance the binding of cGAS to DNA. Retention of TOP1cc to cytoplasmic chromatin depends on its stabilization by the chromatin architecture protein HMGB2. Functionally, the HMGB2-TOP1cc-cGAS axis determines the response of orthotopically transplanted ex vivo therapy-induced senescent cells to immune checkpoint blockade in vivo. Together, these findings establish a HMGB2-TOP1cc-cGAS axis that enables cytoplasmic chromatin recognition and response to immune checkpoint blockade.
Assuntos
Senescência Celular/imunologia , DNA Topoisomerases Tipo I/metabolismo , Proteína HMGB2/metabolismo , Nucleotidiltransferases/metabolismo , Animais , Antígeno B7-H1/imunologia , Linhagem Celular , Cromatina/imunologia , Cromatina/metabolismo , Citosol/imunologia , Citosol/metabolismo , DNA/imunologia , DNA/metabolismo , Dano ao DNA/imunologia , DNA Topoisomerases Tipo I/genética , Técnicas de Silenciamento de Genes , Proteína HMGB2/genética , Humanos , Inflamação , Camundongos , Camundongos Endogâmicos C57BL , Mutação , Neoplasias/imunologia , Nucleotidiltransferases/genética , Ligação Proteica , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Tumor recurrence years after seemingly successful treatment of primary tumors is one of the major causes of mortality in patients with cancer. Reactivation of dormant tumor cells is largely responsible for this phenomenon. Using dormancy models of lung and ovarian cancer, we found a specific mechanism, mediated by stress and neutrophils, that may govern this process. Stress hormones cause rapid release of proinflammatory S100A8/A9 proteins by neutrophils. S100A8/A9 induce activation of myeloperoxidase, resulting in accumulation of oxidized lipids in these cells. Upon release from neutrophils, these lipids up-regulate the fibroblast growth factor pathway in tumor cells, causing tumor cell exit from the dormancy and formation of new tumor lesions. Higher serum concentrations of S100A8/A9 were associated with shorter time to recurrence in patients with lung cancer after complete tumor resection. Targeting of S100A8/A9 or ß2-adrenergic receptors abrogated stress-induced reactivation of dormant tumor cells. These observations demonstrate a mechanism linking stress and specific neutrophil activation with early recurrence in cancer.
Assuntos
Calgranulina B , Neutrófilos , Calgranulina A , Humanos , Lipídeos , Recidiva Local de NeoplasiaRESUMO
We have recently discovered that nicotinamide adenine dinucleotide metabolism controls the pro-inflammatory senescence-associated secretory phenotype during cellular senescence. This newly discovered epigenetic-metabolic signaling axis, mediated by high mobility group A and nicotinamide phosphoribosyltransferase, drives key metabolic changes and pro-inflammatory responses of senescent cells that fuel cancer progression.
RESUMO
Despite the high initial response rates to PARP inhibitors (PARPi) in BRCA-mutated epithelial ovarian cancers (EOC), PARPi resistance remains a major challenge. Chemical modifications of RNAs have emerged as a new layer of epigenetic gene regulation. N6-methyladenosine (m6A) is the most abundant chemical modification of mRNA, yet the role of m6A modification in PARPi resistance has not previously been explored. Here, we show that m6A modification of FZD10 mRNA contributes to PARPi resistance by upregulating the Wnt/ß-catenin pathway in BRCA-mutated EOC cells. Global m6A profile revealed a significant increase in m6A modification in FZD10 mRNA, which correlated with increased FZD10 mRNA stability and an upregulation of the Wnt/ß-catenin pathway. Depletion of FZD10 or inhibition of the Wnt/ß-catenin sensitizes resistant cells to PARPi. Mechanistically, downregulation of m6A demethylases FTO and ALKBH5 was sufficient to increase FZD10 mRNA m6A modification and reduce PARPi sensitivity, which correlated with an increase in homologous recombination activity. Moreover, combined inhibition of PARP and Wnt/ß-catenin showed synergistic suppression of PARPi-resistant cells in vitro and in vivo in a xenograft EOC mouse model. Overall, our results show that m6A contributes to PARPi resistance in BRCA-deficient EOC cells by upregulating the Wnt/ß-catenin pathway via stabilization of FZD10. They also suggest that inhibition of the Wnt/ß-catenin pathway represents a potential strategy to overcome PARPi resistance. SIGNIFICANCE: These findings elucidate a novel regulatory mechanism of PARPi resistance in EOC by showing that m6A modification of FZD10 mRNA contributes to PARPi resistance in BRCA-deficient EOC cells via upregulation of Wnt/ß-catenin pathway.
Assuntos
Adenosina/metabolismo , Resistencia a Medicamentos Antineoplásicos/genética , Receptores Frizzled/genética , Neoplasias Ovarianas/tratamento farmacológico , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Homólogo AlkB 5 da RNA Desmetilase/genética , Dioxigenase FTO Dependente de alfa-Cetoglutarato/genética , Animais , Proteína BRCA2/genética , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Feminino , Receptores Frizzled/metabolismo , Compostos Heterocíclicos com 3 Anéis/farmacologia , Humanos , Metilação , Camundongos SCID , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Ftalazinas/farmacologia , Piperazinas/farmacologia , RNA Mensageiro/metabolismo , Via de Sinalização Wnt/efeitos dos fármacos , Via de Sinalização Wnt/genética , Ensaios Antitumorais Modelo de Xenoenxerto , beta Catenina/genética , beta Catenina/metabolismoRESUMO
ARID1A, encoding a subunit of the SWI/SNF complex, is the most frequently mutated epigenetic regulator in human cancers and is mutated in more than 50% of ovarian clear cell carcinomas (OCCC), a disease that currently has no effective therapy. Inhibition of histone deacetylase 6 (HDAC6) suppresses the growth of ARID1A-mutated tumors and modulates tumor immune microenvironment. Here, we show that inhibition of HDAC6 synergizes with anti-PD-L1 immune checkpoint blockade in ARID1A-inactivated ovarian cancer. ARID1A directly repressed transcription of CD274, the gene encoding PD-L1. Reduced tumor burden and improved survival were observed in ARID1Aflox/flox/PIK3CAH1047R OCCC mice treated with the HDAC6 inhibitor ACY1215 and anti-PD-L1 immune checkpoint blockade as a result of activation and increased presence of IFNγ-positive CD8 T cells. We confirmed that the combined treatment limited tumor progression in a cytotoxic T-cell-dependent manner, as depletion of CD8+ T cells abrogated these antitumor effects. Together, these findings indicate that combined HDAC6 inhibition and immune checkpoint blockade represents a potential treatment strategy for ARID1A-mutated cancers. SIGNIFICANCE: These findings offer a mechanistic rationale for combining epigenetic modulators and existing immunotherapeutic interventions against a disease that has been so far resistant to checkpoint blockade as a monotherapy.See related commentary by Prokunina-Olsson, p. 5476.
Assuntos
Adenocarcinoma de Células Claras , Neoplasias Ovarianas , Animais , Antígeno B7-H1 , Linfócitos T CD8-Positivos , Proteínas de Ligação a DNA , Feminino , Desacetilase 6 de Histona , Humanos , Camundongos , Proteínas Nucleares , Fatores de Transcrição , Microambiente TumoralRESUMO
Senescence is induced by various stimuli such as oncogene expression and telomere shortening, referred to as oncogene-induced senescence (OIS) and replicative senescence (RS), respectively, and accompanied by global transcriptional alterations and 3D genome reorganization. Here, we demonstrate that the human condensin II complex participates in senescence via gene regulation and reorganization of euchromatic A and heterochromatic B compartments. Both OIS and RS are accompanied by A-to-B and B-to-A compartmental transitions, the latter of which occur more frequently and are undergone by 14% (430 Mb) of the human genome. Mechanistically, condensin is enriched in A compartments and implicated in B-to-A transitions. The full activation of senescence genes (SASP genes and p53 targets) requires condensin; its depletion impairs senescence markers. This study describes that condensin reinforces euchromatic A compartments and promotes B-to-A transitions, both of which are coupled to optimal expression of senescence genes, thereby allowing condensin to contribute to senescent processes.
Assuntos
Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/farmacologia , Senescência Celular/genética , Senescência Celular/fisiologia , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Complexos Multiproteicos/metabolismo , Complexos Multiproteicos/farmacologia , Proteínas de Ciclo Celular/genética , Linhagem Celular , Cromatina , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Genômica , Humanos , Proteínas Nucleares/genética , Oncogenes , Regiões Promotoras Genéticas , Encurtamento do Telômero , Proteína Supressora de Tumor p53/genéticaRESUMO
Cellular senescence is a stable growth arrest that is implicated in tissue ageing and cancer. Senescent cells are characterized by an upregulation of proinflammatory cytokines, which is termed the senescence-associated secretory phenotype (SASP). NAD+ metabolism influences both tissue ageing and cancer. However, the role of NAD+ metabolism in regulating the SASP is poorly understood. Here, we show that nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme of the NAD+ salvage pathway, governs the proinflammatory SASP independent of senescence-associated growth arrest. NAMPT expression is regulated by high mobility group A (HMGA) proteins during senescence. The HMGA-NAMPT-NAD+ signalling axis promotes the proinflammatory SASP by enhancing glycolysis and mitochondrial respiration. HMGA proteins and NAMPT promote the proinflammatory SASP through NAD+-mediated suppression of AMPK kinase, which suppresses the p53-mediated inhibition of p38 MAPK to enhance NF-κB activity. We conclude that NAD+ metabolism governs the proinflammatory SASP. Given the tumour-promoting effects of the proinflammatory SASP, our results suggest that anti-ageing dietary NAD+ augmentation should be administered with precision.
Assuntos
Senescência Celular , Citocinas/metabolismo , Mediadores da Inflamação/metabolismo , NAD/metabolismo , Animais , Linhagem Celular , Citocinas/genética , Fibroblastos/metabolismo , Regulação da Expressão Gênica , Humanos , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Nicotinamida Fosforribosiltransferase/genética , Nicotinamida Fosforribosiltransferase/metabolismo , Fenótipo , Transdução de Sinais , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Inhibition of mTOR signaling using rapamycin has been shown to increase lifespan and healthspan in multiple model organisms; however, the precise mechanisms for the beneficial effects of rapamycin remain uncertain. We have previously reported that rapamycin delays senescence in human cells and that enhanced mitochondrial biogenesis and protection from mitochondrial stress is one component of the benefit provided by rapamycin treatment. Here, using two models of senescence, replicative senescence and senescence induced by the presence of the Hutchinson-Gilford progeria lamin A mutation, we report that senescence is accompanied by elevated glycolysis and increased oxidative phosphorylation, which are both reduced by rapamycin. Measurements of mitochondrial function indicate that direct mitochondria targets of rapamycin are succinate dehydrogenase and matrix alanine aminotransferase. Elevated activity of these enzymes could be part of complex mechanisms that enable mitochondria to resume their optimal oxidative phosphorylation and resist senescence. This interpretation is supported by the fact that rapamycin-treated cultures do not undergo a premature senescence in response to the replacement of glucose with galactose in the culture medium, which forces a greater reliance on oxidative phosphorylation. Additionally, long-term treatment with rapamycin increases expression of the mitochondrial carrier protein UCP2, which facilitates the movement of metabolic intermediates across the mitochondrial membrane. The results suggest that rapamycin impacts mitochondrial function both through direct interaction with the mitochondria and through altered gene expression of mitochondrial carrier proteins.
RESUMO
Cellular senescence is a central component of the aging process. This cellular response has been found to be induced by multiple forms of molecular damage and senescent cells increase in number with age in all tissues examined to date. We have examined the correlation with age of two key proteins involved in the senescence program, p16INK4a and HMGB2. These proteins are involved in cell cycle arrest and chromatin remodeling during senescence. Circulating levels of these markers increases with age and correlates with functional status. The levels of HMGB2 appear to be significantly correlated with functional status, whereas p16INK4a levels are more weakly associated. Interestingly, there is a strong correlation between the two proteins independent of age. In particular, a single high-functioning individual over 90 years of age displays a disproportionately low level of HGMB2. The results suggest that with improved testing methodology, it may be possible to monitor circulating protein markers of senescence in human populations.
Assuntos
Atividades Cotidianas , Senescência Celular/fisiologia , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Proteína HMGB2/metabolismo , Saúde Mental , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Biomarcadores/metabolismo , Estudos de Casos e Controles , Células Cultivadas , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Humanos , Masculino , Limitação da Mobilidade , Aptidão Física/fisiologia , Valores de Referência , Medição de Risco , Estudos de Amostragem , Adulto JovemRESUMO
HIV-1 causes premature aging in chronically infected patients. Despite effective anti-retroviral therapy, around 50% of patients suffer HIV-associated neurocognitive disorders (HAND), which likely potentiate aging-associated neurocognitive decline. Microglia support productive HIV-1 infection in the brain. Elevated markers of cellular senescence, including p53 and p21, have been detected in brain tissues from patients with HAND, but the potential for microglia senescence during HIV-1 infection has not been investigated. We hypothesized that HIV-1 can induce senescence in microglia. Primary human fetal microglia were exposed to single-round infectious HIV-1 pseudotypes or controls, and examined for markers of senescence. Post-infection, microglia had significantly elevated: senescence-associated ß-galactosidase activity, p21 levels, and production of cytokines such as IL-6 and IL-8, potentially indicative of a senescence-associated secretory phenotype. We also found increased detection of p53-binding protein foci in microglia nuclei post-infection. Additionally, we examined mitochondrial reactive oxygen species (ROS) and respiration, and found significantly increased mitochondrial ROS levels and decreased ATP-linked respiration during HIV-1 infection. Supernatant transfer from infected cultures to naïve microglia resulted in elevated p21 and caveolin-1 levels, and IL-8 production. Finally, nucleoside treatment reduced senescence markers induction in microglia. Overall, HIV-1 induces a senescence-like phenotype in human microglia, which could play a role in HAND.
Assuntos
Senilidade Prematura , Senescência Celular/fisiologia , Infecções por HIV , Microglia/metabolismo , Senilidade Prematura/etiologia , Senilidade Prematura/metabolismo , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Infecções por HIV/complicações , Infecções por HIV/metabolismo , HIV-1/fisiologia , Humanos , Interleucina-6/metabolismo , Interleucina-8/metabolismo , Mitocôndrias/metabolismo , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , beta-Galactosidase/metabolismoRESUMO
ARID1A, a subunit of the SWI/SNF complex, is among the most frequently mutated genes across cancer types. ARID1A is mutated in more than 50% of ovarian clear cell carcinomas (OCCCs), diseases that have no effective therapy. Here, we show that ARID1A mutation confers sensitivity to pan-HDAC inhibitors such as SAHA in ovarian cancers. This correlated with enhanced growth suppression induced by the inhibition of HDAC2 activity in ARID1A-mutated cells. HDAC2 interacts with EZH2 in an ARID1A status-dependent manner. HDAC2 functions as a co-repressor of EZH2 to suppress the expression of EZH2/ARID1A target tumor suppressor genes such as PIK3IP1 to inhibit proliferation and promote apoptosis. SAHA reduced the growth and ascites of the ARID1A-inactivated OCCCs in both orthotopic and genetic mouse models. This correlated with a significant improvement of survival of mice bearing ARID1A-mutated OCCCs. These findings provided preclinical rationales for repurposing FDA-approved pan-HDAC inhibitors for treating ARID1A-mutated cancers.
Assuntos
Reposicionamento de Medicamentos , Inibidores de Histona Desacetilases/farmacologia , Mutação , Proteínas Nucleares/genética , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Fatores de Transcrição/genética , Animais , Proteínas de Ligação a DNA , Feminino , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas Nucleares/metabolismo , Neoplasias Ovarianas/patologia , Fatores de Transcrição/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Cellular senescence has gained much attention as a contributor to aging and susceptibility to disease. Senescent cells undergo a stable cell cycle arrest and produce pro-inflammatory cytokines. However, an additional feature of the senescence phenotype is an altered metabolic state. Despite maintaining a non-dividing state, senescent cells display a high metabolic rate. Metabolic changes characteristic of replicative senescence include altered mitochondrial function and perturbations in growth signaling pathways, such as the mTORC1-signaling pathway. Recent evidence has raised the possibility that these metabolic changes may be essential for the induction and maintenance of the senescent state. Interventions such as rapamycin treatment and methionine restriction impact key aspects of metabolism and delay cellular senescence to extend cellular lifespan. Here, we review the metabolic changes and potential metabolic regulators of the senescence program. In addition, we will discuss how lifespan-extending regimens prevent metabolic stress that accompanies and potentially regulates the senescence program.
Assuntos
Envelhecimento/metabolismo , Proteínas de Ciclo Celular/genética , Senescência Celular/genética , Complexo de Proteínas da Cadeia de Transporte de Elétrons/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Mitocôndrias/metabolismo , Envelhecimento/efeitos dos fármacos , Envelhecimento/genética , Animais , Proteínas de Ciclo Celular/metabolismo , Senescência Celular/efeitos dos fármacos , Citocinas/genética , Citocinas/metabolismo , Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Regulação da Expressão Gênica , Glucose/metabolismo , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina/antagonistas & inibidores , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Metionina/administração & dosagem , Metionina/deficiência , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Fenótipo , Transdução de Sinais , Sirolimo/farmacologiaRESUMO
Cellular senescence is a tumor suppressive response that has become recognized as a major contributor of tissue aging. Senescent cells undergo a stable proliferative arrest that protects against neoplastic transformation, but acquire a secretory phenotype that has long-term deleterious effects. Studies are still unraveling the effector mechanisms that underlie these senescence responses with the goal to identify therapeutic interventions. Such effector mechanisms have been linked to the dramatic remodeling in the epigenetic and chromatin landscape that accompany cellular senescence. We discuss these senescence-associated epigenetic changes and their impact on the senescence phenotypes, notably the proliferative arrest and senescence associated secretory phenotype (SASP). We also explore possible epigenetic targets to suppress the deleterious effects of senescent cells that contribute towards aging.