RESUMO
The story of p53 is illuminating. Despite widespread attention, the tumor-suppressive functions of wild-type p53 or the oncogenic activities of its cancer-associated mutants are still not fully understood, and our discoveries have not yet led to major therapeutic breakthroughs. There is still much to learn about this fascinating protein.
Assuntos
Neoplasias , Proteína Supressora de Tumor p53 , Humanos , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Neoplasias/genética , Neoplasias/tratamento farmacológico , MutaçãoRESUMO
Lysine lactylation is a post-translational modification that links cellular metabolism to protein function. Here, we find that AARS1 functions as a lactate sensor that mediates global lysine lacylation in tumor cells. AARS1 binds to lactate and catalyzes the formation of lactate-AMP, followed by transfer of lactate to the lysince acceptor residue. Proteomics studies reveal a large number of AARS1 targets, including p53 where lysine 120 and lysine 139 in the DNA binding domain are lactylated. Generation and utilization of p53 variants carrying constitutively lactylated lysine residues revealed that AARS1 lactylation of p53 hinders its liquid-liquid phase separation, DNA binding, and transcriptional activation. AARS1 expression and p53 lacylation correlate with poor prognosis among cancer patients carrying wild type p53. ß-alanine disrupts lactate binding to AARS1, reduces p53 lacylation, and mitigates tumorigenesis in animal models. We propose that AARS1 contributes to tumorigenesis by coupling tumor cell metabolism to proteome alteration.
Assuntos
Carcinogênese , Ácido Láctico , Proteína Supressora de Tumor p53 , Animais , Feminino , Humanos , Camundongos , Carcinogênese/metabolismo , Carcinogênese/genética , Linhagem Celular Tumoral , Ácido Láctico/metabolismo , Lisina/metabolismo , Neoplasias/metabolismo , Neoplasias/genética , Processamento de Proteína Pós-Traducional , Proteína Supressora de Tumor p53/metabolismo , MasculinoRESUMO
Ongoing, early-stage clinical trials illustrate the translational potential of human pluripotent stem cell (hPSC)-based cell therapies in Parkinson's disease (PD). However, an unresolved challenge is the extensive cell death following transplantation. Here, we performed a pooled CRISPR-Cas9 screen to enhance postmitotic dopamine neuron survival in vivo. We identified p53-mediated apoptotic cell death as a major contributor to dopamine neuron loss and uncovered a causal link of tumor necrosis factor alpha (TNF-α)-nuclear factor κB (NF-κB) signaling in limiting cell survival. As a translationally relevant strategy to purify postmitotic dopamine neurons, we identified cell surface markers that enable purification without the need for genetic reporters. Combining cell sorting and treatment with adalimumab, a clinically approved TNF-α inhibitor, enabled efficient engraftment of postmitotic dopamine neurons with extensive reinnervation and functional recovery in a preclinical PD mouse model. Thus, transient TNF-α inhibition presents a clinically relevant strategy to enhance survival and enable engraftment of postmitotic hPSC-derived dopamine neurons in PD.
Assuntos
Sobrevivência Celular , Neurônios Dopaminérgicos , NF-kappa B , Fator de Necrose Tumoral alfa , Proteína Supressora de Tumor p53 , Neurônios Dopaminérgicos/metabolismo , Animais , Humanos , NF-kappa B/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Camundongos , Sobrevivência Celular/efeitos dos fármacos , Transdução de Sinais , Doença de Parkinson/metabolismo , Células-Tronco Pluripotentes/metabolismo , Apoptose , Modelos Animais de Doenças , Sistemas CRISPR-CasRESUMO
Whole-genome duplication (WGD) is a frequent event in cancer evolution and an important driver of aneuploidy. The role of the p53 tumor suppressor in WGD has been enigmatic: p53 can block the proliferation of tetraploid cells, acting as a barrier to WGD, but can also promote mitotic bypass, a key step in WGD via endoreduplication. In wild-type (WT) p53 tumors, WGD is frequently associated with activation of the E2F pathway, especially amplification of CCNE1, encoding cyclin E1. Here, we show that elevated cyclin E1 expression causes replicative stress, which activates ATR- and Chk1-dependent G2 phase arrest. p53, via its downstream target p21, together with Wee1, then inhibits mitotic cyclin-dependent kinase activity sufficiently to activate APC/CCdh1 and promote mitotic bypass. Cyclin E expression suppresses p53-dependent senescence after mitotic bypass, allowing cells to complete endoreduplication. Our results indicate that p53 can contribute to cancer evolution through the promotion of WGD.
Assuntos
Ciclina E , Duplicação Gênica , Neoplasias , Proteína Supressora de Tumor p53 , Humanos , Linhagem Celular Tumoral , Ciclina E/genética , Ciclina E/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/genética , Mitose , Neoplasias/genética , Neoplasias/patologia , Proteína Supressora de Tumor p53/metabolismoRESUMO
Living organisms are constantly exposed to DNA damage, and optimal repair is therefore crucial. A characteristic hallmark of the response is the formation of sub-compartments around the site of damage, known as foci. Following multiple DNA breaks, the transcription factor p53 exhibits oscillations in its nuclear concentration, but how this dynamics can affect the repair remains unknown. Here, we formulate a theory for foci formation through droplet condensation and discover how oscillations in p53, with its specific periodicity and amplitude, optimize the repair process by preventing Ostwald ripening and distributing protein material in space and time. Based on the theory predictions, we reveal experimentally that the oscillatory dynamics of p53 does enhance the repair efficiency. These results connect the dynamical signaling of p53 with the microscopic repair process and create a new paradigm for the interplay of complex dynamics and phase transitions in biology.
Assuntos
Proteínas Proto-Oncogênicas c-mdm2 , Proteína Supressora de Tumor p53 , Proteína Supressora de Tumor p53/metabolismo , Proteínas Proto-Oncogênicas c-mdm2/genética , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Reparo do DNA , Dano ao DNA , Transdução de Sinais/fisiologiaRESUMO
The most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is a GGGGCC repeat expansion in the C9orf72 gene. We developed a platform to interrogate the chromatin accessibility landscape and transcriptional program within neurons during degeneration. We provide evidence that neurons expressing the dipeptide repeat protein poly(proline-arginine), translated from the C9orf72 repeat expansion, activate a highly specific transcriptional program, exemplified by a single transcription factor, p53. Ablating p53 in mice completely rescued neurons from degeneration and markedly increased survival in a C9orf72 mouse model. p53 reduction also rescued axonal degeneration caused by poly(glycine-arginine), increased survival of C9orf72 ALS/FTD-patient-induced pluripotent stem cell (iPSC)-derived motor neurons, and mitigated neurodegeneration in a C9orf72 fly model. We show that p53 activates a downstream transcriptional program, including Puma, which drives neurodegeneration. These data demonstrate a neurodegenerative mechanism dynamically regulated through transcription-factor-binding events and provide a framework to apply chromatin accessibility and transcription program profiles to neurodegeneration.
Assuntos
Proteína C9orf72/metabolismo , Expansão das Repetições de DNA/genética , Degeneração Neural/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Axônios/metabolismo , Proteína C9orf72/genética , Morte Celular , Células Cultivadas , Córtex Cerebral/patologia , Cromatina/metabolismo , Dano ao DNA , Modelos Animais de Doenças , Drosophila , Camundongos Endogâmicos C57BL , Degeneração Neural/patologia , Estabilidade Proteica , Transcrição Gênica , Proteínas Supressoras de Tumor/metabolismoRESUMO
Cells confront DNA damage in every cell cycle. Among the most deleterious types of DNA damage are DNA double-strand breaks (DSBs), which can cause cell lethality if unrepaired or cancers if improperly repaired. In response to DNA DSBs, cells activate a complex DNA damage checkpoint (DDC) response that arrests the cell cycle, reprograms gene expression, and mobilizes DNA repair factors to prevent the inheritance of unrepaired and broken chromosomes. Here we examine the DDC, induced by DNA DSBs, in the budding yeast model system and in mammals.
Assuntos
Pontos de Checagem do Ciclo Celular/genética , Reparo do DNA por Junção de Extremidades , DNA/genética , Reparo de DNA por Recombinação , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Animais , Proteínas Mutadas de Ataxia Telangiectasia/química , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Quinase 1 do Ponto de Checagem/genética , Quinase 1 do Ponto de Checagem/metabolismo , Quinase do Ponto de Checagem 2/genética , Quinase do Ponto de Checagem 2/metabolismo , DNA/química , DNA/metabolismo , Quebras de DNA de Cadeia Dupla , Humanos , Modelos Moleculares , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Estrutura Secundária de Proteína , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
The volume-regulated anion channel (VRAC) is formed by LRRC8 proteins and is responsible for the regulatory volume decrease (RVD) after hypotonic cell swelling. Besides chloride, VRAC transports other molecules, for example, immunomodulatory cyclic dinucleotides (CDNs) including 2'3'cGAMP. Here, we identify LRRC8C as a critical component of VRAC in T cells, where its deletion abolishes VRAC currents and RVD. T cells of Lrrc8c-/- mice have increased cell cycle progression, proliferation, survival, Ca2+ influx and cytokine production-a phenotype associated with downmodulation of p53 signaling. Mechanistically, LRRC8C mediates the transport of 2'3'cGAMP in T cells, resulting in STING and p53 activation. Inhibition of STING recapitulates the phenotype of LRRC8C-deficient T cells, whereas overexpression of p53 inhibits their enhanced T cell function. Lrrc8c-/- mice have exacerbated T cell-dependent immune responses, including immunity to influenza A virus infection and experimental autoimmune encephalomyelitis. Our results identify cGAMP uptake through LRRC8C and STING-p53 signaling as a new inhibitory signaling pathway in T cells and adaptive immunity.
Assuntos
Ânions/metabolismo , Fosfatos de Dinucleosídeos/metabolismo , Canais Iônicos/metabolismo , Proteínas de Membrana/metabolismo , Linfócitos T/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Cálcio/metabolismo , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Nucleotídeos Cíclicos/metabolismo , Transdução de Sinais/fisiologiaRESUMO
Pulmonary neuroendocrine (NE) cells are neurosensory cells sparsely distributed throughout the bronchial epithelium, many in innervated clusters of 20-30 cells. Following lung injury, NE cells proliferate and generate other cell types to promote epithelial repair. Here, we show that only rare NE cells, typically 2-4 per cluster, function as stem cells. These fully differentiated cells display features of classical stem cells. Most proliferate (self-renew) following injury, and some migrate into the injured area. A week later, individual cells, often just one per cluster, lose NE identity (deprogram), transit amplify, and reprogram to other fates, creating large clonal repair patches. Small cell lung cancer (SCLC) tumor suppressors regulate the stem cells: Rb and p53 suppress self-renewal, whereas Notch marks the stem cells and initiates deprogramming and transit amplification. We propose that NE stem cells give rise to SCLC, and transformation results from constitutive activation of stem cell renewal and inhibition of deprogramming.
Assuntos
Transformação Celular Neoplásica/patologia , Neoplasias Pulmonares/patologia , Pulmão/patologia , Células-Tronco Neoplásicas/patologia , Células Neuroendócrinas/patologia , Receptores Notch/metabolismo , Proteína do Retinoblastoma/metabolismo , Carcinoma de Pequenas Células do Pulmão/patologia , Proteína Supressora de Tumor p53/metabolismo , Animais , Diferenciação Celular , Transformação Celular Neoplásica/metabolismo , Lesão Pulmonar/patologia , Neoplasias Pulmonares/metabolismo , Camundongos , Células-Tronco Neoplásicas/metabolismo , Células Neuroendócrinas/metabolismo , Análise de Célula Única/métodos , Carcinoma de Pequenas Células do Pulmão/metabolismoRESUMO
There are still gaps in our understanding of the complex processes by which p53 suppresses tumorigenesis. Here we describe a novel role for p53 in suppressing the mevalonate pathway, which is responsible for biosynthesis of cholesterol and nonsterol isoprenoids. p53 blocks activation of SREBP-2, the master transcriptional regulator of this pathway, by transcriptionally inducing the ABCA1 cholesterol transporter gene. A mouse model of liver cancer reveals that downregulation of mevalonate pathway gene expression by p53 occurs in premalignant hepatocytes, when p53 is needed to actively suppress tumorigenesis. Furthermore, pharmacological or RNAi inhibition of the mevalonate pathway restricts the development of murine hepatocellular carcinomas driven by p53 loss. Like p53 loss, ablation of ABCA1 promotes murine liver tumorigenesis and is associated with increased SREBP-2 maturation. Our findings demonstrate that repression of the mevalonate pathway is a crucial component of p53-mediated liver tumor suppression and outline the mechanism by which this occurs.
Assuntos
Ácido Mevalônico/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Animais , Linhagem Celular , Colesterol/metabolismo , Feminino , Genes Supressores de Tumor , Células HCT116 , Hepatócitos/metabolismo , Humanos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias/genética , Regiões Promotoras Genéticas , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Terpenos/metabolismoRESUMO
Chemotherapy is designed to induce cell death. However, at non-lethal doses, cancer cells can choose to remain proliferative or become senescent. The slow development of senescence makes studying this decision challenging. Here, by analyzing single-cell p21 dynamics before, during, and days after drug treatment, we link three distinct patterns of early p21 dynamics to final cell fate. Surprisingly, while high p21 expression is classically associated with senescence, we find the opposite at early times during drug treatment: most senescence-fated cells express much lower p21 levels than proliferation-fated cells. We demonstrate that these dynamics lead to a p21 "Goldilocks zone" for proliferation, in which modest increases of p21 expression can lead to an undesirable increase of cancer cell proliferation. Our study identifies a counter-intuitive role for early p21 dynamics in the cell-fate decision and pinpoints a source of proliferative cancer cells that can emerge after exposure to non-lethal doses of chemotherapy.
Assuntos
Proliferação de Células/efeitos dos fármacos , Senescência Celular/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Doxorrubicina/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Quinase 1 do Ponto de Checagem/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/antagonistas & inibidores , Inibidor de Quinase Dependente de Ciclina p21/genética , Dano ao DNA/efeitos dos fármacos , Humanos , Modelos Biológicos , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Proteína Supressora de Tumor p53/metabolismoRESUMO
Targeting the p53-MDM2 pathway to reactivate tumor p53 is a chemotherapeutic approach. However, the involvement of this pathway in CD8+ T cell-mediated antitumor immunity is unknown. Here, we report that mice with MDM2 deficiency in T cells exhibit accelerated tumor progression and a decrease in tumor-infiltrating CD8+ T cell survival and function. Mechanistically, MDM2 competes with c-Cbl for STAT5 binding, reduces c-Cbl-mediated STAT5 degradation and enhances STAT5 stability in tumor-infiltrating CD8+ T cells. Targeting the p53-MDM2 interaction with a pharmacological agent, APG-115, augmented MDM2 in T cells, thereby stabilizing STAT5, boosting T cell immunity and synergizing with cancer immunotherapy. Unexpectedly, these effects of APG-115 were dependent on p53 and MDM2 in T cells. Clinically, MDM2 abundance correlated with T cell function and interferon-γ signature in patients with cancer. Thus, the p53-MDM2 pathway controls T cell immunity, and targeting this pathway may treat patients with cancer regardless of tumor p53 status.
Assuntos
Linfócitos T CD8-Positivos/enzimologia , Linfócitos do Interstício Tumoral/enzimologia , Neoplasias/enzimologia , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Fator de Transcrição STAT5/metabolismo , Animais , Antineoplásicos/farmacologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/transplante , Linhagem Celular Tumoral , Terapia Combinada , Feminino , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Humanos , Imunoterapia Adotiva , Linfócitos do Interstício Tumoral/efeitos dos fármacos , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/transplante , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neoplasias/genética , Neoplasias/imunologia , Neoplasias/terapia , Estabilidade Proteica , Proteólise , Proteínas Proto-Oncogênicas c-mdm2/genética , Fator de Transcrição STAT5/genética , Transdução de Sinais , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
Patients with myelodysplastic syndromes (MDSs) display severe anemia but the mechanisms underlying this phenotype are incompletely understood. Right open-reading-frame kinase 2 (RIOK2) encodes a protein kinase located at 5q15, a region frequently lost in patients with MDS del(5q). Here we show that hematopoietic cell-specific haploinsufficient deletion of Riok2 (Riok2f/+Vav1cre) led to reduced erythroid precursor frequency leading to anemia. Proteomic analysis of Riok2f/+Vav1cre erythroid precursors suggested immune system activation, and transcriptomic analysis revealed an increase in p53-dependent interleukin (IL)-22 in Riok2f/+Vav1cre CD4+ T cells (TH22). Further, we discovered that the IL-22 receptor, IL-22RA1, was unexpectedly present on erythroid precursors. Blockade of IL-22 signaling alleviated anemia not only in Riok2f/+Vav1cre mice but also in wild-type mice. Serum concentrations of IL-22 were increased in the subset of patients with del(5q) MDS as well as patients with anemia secondary to chronic kidney disease. This work reveals a possible therapeutic opportunity for reversing many stress-induced anemias by targeting IL-22 signaling.
Assuntos
Anemia/metabolismo , Anticorpos Neutralizantes/farmacologia , Células Eritroides/metabolismo , Eritropoese/efeitos dos fármacos , Interleucinas/antagonistas & inibidores , Síndromes Mielodisplásicas/tratamento farmacológico , Receptores de Interleucina/metabolismo , Anemia/sangue , Anemia/imunologia , Anemia/prevenção & controle , Animais , Células Cultivadas , Microambiente Celular , Modelos Animais de Doenças , Células Eritroides/imunologia , Humanos , Interleucinas/imunologia , Interleucinas/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Síndromes Mielodisplásicas/sangue , Síndromes Mielodisplásicas/imunologia , Síndromes Mielodisplásicas/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-vav/genética , Proteínas Proto-Oncogênicas c-vav/metabolismo , Receptores de Interleucina/genética , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/imunologia , Insuficiência Renal Crônica/metabolismo , Transdução de Sinais , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Interleucina 22RESUMO
While mutations affecting protein-coding regions have been examined across many cancers, structural variants at the genome-wide level are still poorly defined. Through integrative deep whole-genome and -transcriptome analysis of 101 castration-resistant prostate cancer metastases (109X tumor/38X normal coverage), we identified structural variants altering critical regulators of tumorigenesis and progression not detectable by exome approaches. Notably, we observed amplification of an intergenic enhancer region 624 kb upstream of the androgen receptor (AR) in 81% of patients, correlating with increased AR expression. Tandem duplication hotspots also occur near MYC, in lncRNAs associated with post-translational MYC regulation. Classes of structural variations were linked to distinct DNA repair deficiencies, suggesting their etiology, including associations of CDK12 mutation with tandem duplications, TP53 inactivation with inverted rearrangements and chromothripsis, and BRCA2 inactivation with deletions. Together, these observations provide a comprehensive view of how structural variations affect critical regulators in metastatic prostate cancer.
Assuntos
Variação Estrutural do Genoma/genética , Neoplasias da Próstata/genética , Idoso , Idoso de 80 Anos ou mais , Proteína BRCA2/metabolismo , Quinases Ciclina-Dependentes/metabolismo , Variações do Número de Cópias de DNA , Exoma , Perfilação da Expressão Gênica/métodos , Genômica/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Metástase Neoplásica/genética , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , Sequências de Repetição em Tandem/genética , Proteína Supressora de Tumor p53/metabolismo , Sequenciamento Completo do Genoma/métodosRESUMO
Genetic alterations in signaling pathways that control cell-cycle progression, apoptosis, and cell growth are common hallmarks of cancer, but the extent, mechanisms, and co-occurrence of alterations in these pathways differ between individual tumors and tumor types. Using mutations, copy-number changes, mRNA expression, gene fusions and DNA methylation in 9,125 tumors profiled by The Cancer Genome Atlas (TCGA), we analyzed the mechanisms and patterns of somatic alterations in ten canonical pathways: cell cycle, Hippo, Myc, Notch, Nrf2, PI-3-Kinase/Akt, RTK-RAS, TGFß signaling, p53 and ß-catenin/Wnt. We charted the detailed landscape of pathway alterations in 33 cancer types, stratified into 64 subtypes, and identified patterns of co-occurrence and mutual exclusivity. Eighty-nine percent of tumors had at least one driver alteration in these pathways, and 57% percent of tumors had at least one alteration potentially targetable by currently available drugs. Thirty percent of tumors had multiple targetable alterations, indicating opportunities for combination therapy.
Assuntos
Bases de Dados Genéticas , Neoplasias/patologia , Transdução de Sinais/genética , Genes Neoplásicos , Humanos , Neoplasias/genética , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Proteínas Wnt/genética , Proteínas Wnt/metabolismoRESUMO
Low-grade gliomas almost invariably progress into secondary glioblastoma (sGBM) with limited therapeutic option and poorly understood mechanism. By studying the mutational landscape of 188 sGBMs, we find significant enrichment of TP53 mutations, somatic hypermutation, MET-exon-14-skipping (METex14), PTPRZ1-MET (ZM) fusions, and MET amplification. Strikingly, METex14 frequently co-occurs with ZM fusion and is present in â¼14% of cases with significantly worse prognosis. Subsequent studies show that METex14 promotes glioma progression by prolonging MET activity. Furthermore, we describe a MET kinase inhibitor, PLB-1001, that demonstrates remarkable potency in selectively inhibiting MET-altered tumor cells in preclinical models. Importantly, this compound also shows blood-brain barrier permeability and is subsequently applied in a phase I clinical trial that enrolls MET-altered chemo-resistant glioma patients. Encouragingly, PLB-1001 achieves partial response in at least two advanced sGBM patients with rarely significant side effects, underscoring the clinical potential for precisely treating gliomas using this therapy.
Assuntos
Neoplasias Encefálicas , Éxons , Glioblastoma , Mutação , Inibidores de Proteínas Quinases , Proteínas Proto-Oncogênicas c-met , Animais , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/patologia , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Sistemas de Liberação de Medicamentos , Feminino , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Glioblastoma/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Inibidores de Proteínas Quinases/farmacocinética , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-met/genética , Proteínas Proto-Oncogênicas c-met/metabolismo , Ratos Sprague-Dawley , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Genetic drivers of cancer can be dysregulated through epigenetic modifications of DNA. Although the critical role of DNA 5-methylcytosine (5mC) in the regulation of transcription is recognized, the functions of other non-canonical DNA modifications remain obscure. Here, we report the identification of novel N6-methyladenine (N6-mA) DNA modifications in human tissues and implicate this epigenetic mark in human disease, specifically the highly malignant brain cancer glioblastoma. Glioblastoma markedly upregulated N6-mA levels, which co-localized with heterochromatic histone modifications, predominantly H3K9me3. N6-mA levels were dynamically regulated by the DNA demethylase ALKBH1, depletion of which led to transcriptional silencing of oncogenic pathways through decreasing chromatin accessibility. Targeting the N6-mA regulator ALKBH1 in patient-derived human glioblastoma models inhibited tumor cell proliferation and extended the survival of tumor-bearing mice, supporting this novel DNA modification as a potential therapeutic target for glioblastoma. Collectively, our results uncover a novel epigenetic node in cancer through the DNA modification N6-mA.
Assuntos
Adenina/análogos & derivados , Neoplasias Encefálicas/patologia , Metilação de DNA , Glioblastoma/patologia , Adenina/análise , Adenina/química , Adulto , Idoso , Homólogo AlkB 1 da Histona H2a Dioxigenase/antagonistas & inibidores , Homólogo AlkB 1 da Histona H2a Dioxigenase/genética , Homólogo AlkB 1 da Histona H2a Dioxigenase/metabolismo , Animais , Astrócitos/citologia , Astrócitos/metabolismo , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/mortalidade , Hipóxia Celular , Criança , Epigenômica , Feminino , Glioblastoma/metabolismo , Glioblastoma/mortalidade , Heterocromatina/metabolismo , Histonas/metabolismo , Humanos , Estimativa de Kaplan-Meier , Masculino , Camundongos , Pessoa de Meia-Idade , Células-Tronco Neoplásicas/citologia , Células-Tronco Neoplásicas/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Proteína Supressora de Tumor p53/metabolismoRESUMO
TP53 is the most frequently mutated gene in human cancer. Functionally, p53 is activated by a host of stress stimuli and, in turn, governs an exquisitely complex anti-proliferative transcriptional program that touches upon a bewildering array of biological responses. Despite the many unveiled facets of the p53 network, a clear appreciation of how and in what contexts p53 exerts its diverse effects remains unclear. How can we interpret p53's disparate activities and the consequences of its dysfunction to understand how cell type, mutation profile, and epigenetic cell state dictate outcomes, and how might we restore its tumor-suppressive activities in cancer?
Assuntos
Neoplasias/genética , Proteína Supressora de Tumor p53/metabolismo , Animais , Epigênese Genética , Genes p53 , Humanos , Mutação , Neoplasias/metabolismo , Proteína Supressora de Tumor p53/genéticaRESUMO
The accumulation of irreparable cellular damage restricts healthspan after acute stress or natural aging. Senescent cells are thought to impair tissue function, and their genetic clearance can delay features of aging. Identifying how senescent cells avoid apoptosis allows for the prospective design of anti-senescence compounds to address whether homeostasis can also be restored. Here, we identify FOXO4 as a pivot in senescent cell viability. We designed a FOXO4 peptide that perturbs the FOXO4 interaction with p53. In senescent cells, this selectively causes p53 nuclear exclusion and cell-intrinsic apoptosis. Under conditions where it was well tolerated in vivo, this FOXO4 peptide neutralized doxorubicin-induced chemotoxicity. Moreover, it restored fitness, fur density, and renal function in both fast aging XpdTTD/TTD and naturally aged mice. Thus, therapeutic targeting of senescent cells is feasible under conditions where loss of health has already occurred, and in doing so tissue homeostasis can effectively be restored.
Assuntos
Envelhecimento/patologia , Antibióticos Antineoplásicos/efeitos adversos , Peptídeos Penetradores de Células/farmacologia , Doxorrubicina/efeitos adversos , Envelhecimento/efeitos dos fármacos , Animais , Antibióticos Antineoplásicos/administração & dosagem , Antibióticos Antineoplásicos/farmacologia , Apoptose , Proteínas de Ciclo Celular , Linhagem Celular , Sobrevivência Celular , Senescência Celular/efeitos dos fármacos , Doxorrubicina/administração & dosagem , Doxorrubicina/farmacologia , Feminino , Fibroblastos/citologia , Fatores de Transcrição Forkhead/química , Fatores de Transcrição Forkhead/metabolismo , Humanos , Corpos de Inclusão/efeitos dos fármacos , Corpos de Inclusão/metabolismo , Corpos de Inclusão/patologia , Rim/efeitos dos fármacos , Rim/fisiologia , Fígado/efeitos dos fármacos , Fígado/fisiologia , Masculino , Camundongos , Síndromes de Tricotiodistrofia/tratamento farmacológico , Proteína Supressora de Tumor p53/metabolismoRESUMO
J-domain proteins (JDPs) constitute a large family of molecular chaperones that bind a broad spectrum of substrates, targeting them to Hsp70, thus determining the specificity of and activating the entire chaperone functional cycle. The malfunction of JDPs is therefore inextricably linked to myriad human disorders. Here, we uncover a unique mechanism by which chaperones recognize misfolded clients, present in human class A JDPs. Through a newly identified ß-hairpin site, these chaperones detect changes in protein dynamics at the initial stages of misfolding, prior to exposure of hydrophobic regions or large structural rearrangements. The JDPs then sequester misfolding-prone proteins into large oligomeric assemblies, protecting them from aggregation. Through this mechanism, class A JDPs bind destabilized p53 mutants, preventing clearance of these oncoproteins by Hsp70-mediated degradation, thus promoting cancer progression. Removal of the ß-hairpin abrogates this protective activity while minimally affecting other chaperoning functions. This suggests the class A JDP ß-hairpin as a highly specific target for cancer therapeutics.