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1.
Cell ; 177(3): 622-638.e22, 2019 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-31002797

RESUMO

DNA repair has been hypothesized to be a longevity determinant, but the evidence for it is based largely on accelerated aging phenotypes of DNA repair mutants. Here, using a panel of 18 rodent species with diverse lifespans, we show that more robust DNA double-strand break (DSB) repair, but not nucleotide excision repair (NER), coevolves with longevity. Evolution of NER, unlike DSB, is shaped primarily by sunlight exposure. We further show that the capacity of the SIRT6 protein to promote DSB repair accounts for a major part of the variation in DSB repair efficacy between short- and long-lived species. We dissected the molecular differences between a weak (mouse) and a strong (beaver) SIRT6 protein and identified five amino acid residues that are fully responsible for their differential activities. Our findings demonstrate that DSB repair and SIRT6 have been optimized during the evolution of longevity, which provides new targets for anti-aging interventions.


Assuntos
Quebras de DNA de Cadeia Dupla , Reparo do DNA , Longevidade/genética , Sirtuínas/metabolismo , Sequência de Aminoácidos , Animais , Peso Corporal , Quebras de DNA de Cadeia Dupla/efeitos da radiação , Evolução Molecular , Fibroblastos/citologia , Fibroblastos/metabolismo , Técnicas de Inativação de Genes , Humanos , Cinética , Masculino , Mutagênese , Filogenia , Roedores/classificação , Alinhamento de Sequência , Sirtuínas/química , Sirtuínas/genética , Raios Ultravioleta
2.
Mol Cell ; 82(11): 2032-2049.e7, 2022 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-35460603

RESUMO

Virus infection modulates both host immunity and host genomic stability. Poly(ADP-ribose) polymerase 1 (PARP1) is a key nuclear sensor of DNA damage, which maintains genomic integrity, and the successful application of PARP1 inhibitors for clinical anti-cancer therapy has lasted for decades. However, precisely how PARP1 gains access to cytoplasm and regulates antiviral immunity remains unknown. Here, we report that DNA virus induces a reactive nitrogen species (RNS)-dependent DNA damage and activates DNA-dependent protein kinase (DNA-PK). Activated DNA-PK phosphorylates PARP1 on Thr594, thus facilitating the cytoplasmic translocation of PARP1 to inhibit the antiviral immunity both in vitro and in vivo. Mechanistically, cytoplasmic PARP1 interacts with and directly PARylates cyclic GMP-AMP synthase (cGAS) on Asp191 to inhibit its DNA-binding ability. Together, our findings uncover an essential role of PARP1 in linking virus-induced genome instability with inhibition of host immunity, which is of relevance to cancer, autoinflammation, and other diseases.


Assuntos
Antivirais , Nucleotidiltransferases , Antivirais/farmacologia , Citoplasma/genética , Citoplasma/metabolismo , DNA , Dano ao DNA , Instabilidade Genômica , Humanos , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , Poli(ADP-Ribose) Polimerase-1/metabolismo
3.
EMBO Rep ; 25(8): 3263-3275, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38866979

RESUMO

As a hallmark of senescent cells, the derepression of Long Interspersed Elements 1 (LINE1) transcription results in accumulated LINE1 cDNA, which triggers the secretion of the senescence-associated secretory phenotype (SASP) and paracrine senescence in a cGAS-STING pathway-dependent manner. However, transcription factors that govern senescence-associated LINE1 reactivation remain ill-defined. Here, we predict several transcription factors that bind to human LINE1 elements to regulate their transcription by analyzing the conserved binding motifs in the 5'-untranslated regions (UTR) of the commonly upregulated LINE1 elements in different types of senescent cells. Further analysis reveals that PAX5 directly binds to LINE1 5'-UTR and the binding is enhanced in senescent cells. The enrichment of PAX5 at the 5'-UTR promotes cellular senescence and SASP by activating LINE1. We also demonstrate that the longevity gene SIRT6 suppresses PAX5 transcription by directly binding to the PAX5 promoter, and overexpressing PAX5 abrogates the suppressive effect of SIRT6 on stress-dependent cellular senescence. Our work suggests that PAX5 could serve as a potential target for drug development aiming to suppress LINE1 activation and treat senescence-associated diseases.


Assuntos
Senescência Celular , Elementos Nucleotídeos Longos e Dispersos , Fator de Transcrição PAX5 , Humanos , Regiões 5' não Traduzidas/genética , Regulação da Expressão Gênica , Fator de Transcrição PAX5/genética , Fator de Transcrição PAX5/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Retroelementos/genética , Fenótipo Secretor Associado à Senescência/genética
4.
Nucleic Acids Res ; 52(9): 5107-5120, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38554113

RESUMO

Sirtuin 2 (SIRT2) regulates the maintenance of genome integrity by targeting pathways of DNA damage response and homologous recombination repair. However, whether and how SIRT2 promotes base excision repair (BER) remain to be determined. Here, we found that independent of its catalytic activity SIRT2 interacted with the critical glycosylase OGG1 to promote OGG1 recruitment to its own promoter upon oxidative stress, thereby enhancing OGG1 promoter activity and increasing BER efficiency. Further studies revealed that SIRT2 was phosphorylated on S46 and S53 by ATM/ATR upon oxidative stress, and SIRT2 phosphorylation enhanced the SIRT2-OGG1 interaction and mediated the stimulatory effect of SIRT2 on OGG1 promoter activity. We also characterized 37 cancer-derived SIRT2 mutants and found that 5 exhibited the loss of the stimulatory effects on OGG1 transcription. Together, our data reveal that SIRT2 acts as a tumor suppressor by promoting OGG1 transcription and increasing BER efficiency in an ATM/ATR-dependent manner.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia , DNA Glicosilases , Reparo do DNA , Sirtuína 2 , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia/genética , Humanos , Sirtuína 2/metabolismo , Sirtuína 2/genética , DNA Glicosilases/metabolismo , DNA Glicosilases/genética , Fosforilação , Regiões Promotoras Genéticas , Estresse Oxidativo , Ativação Transcricional , Células HEK293 , Dano ao DNA , Transcrição Gênica , Linhagem Celular Tumoral , Reparo por Excisão
5.
Proc Natl Acad Sci U S A ; 120(47): e2309200120, 2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-37967221

RESUMO

Patients with Hutchinson-Gilford progeria syndrome (HGPS) present with a number of premature aging phenotypes, including DNA damage accumulation, and many of them die of cardiovascular complications. Although vascular pathologies have been reported, whether HGPS patients exhibit cardiac dysfunction and its underlying mechanism is unclear, rendering limited options for treating HGPS-related cardiomyopathy. In this study, we reported a cardiac atrophy phenotype in the LmnaG609G/G609G mice (hereafter, HGPS mice). Using a GFP-based reporter system, we demonstrated that the efficiency of nonhomologous end joining (NHEJ) declined by 50% in HGPS cardiomyocytes in vivo, due to the attenuated interaction between γH2AX and Progerin, the causative factor of HGPS. As a result, genomic instability in cardiomyocytes led to an increase of CHK2 protein level, promoting the LKB1-AMPKα interaction and AMPKα phosphorylation, which further led to the activation of FOXO3A-mediated transcription of atrophy-related genes. Moreover, inhibiting AMPK enlarged cardiomyocyte sizes both in vitro and in vivo. Most importantly, our proof-of-concept study indicated that isoproterenol treatment significantly reduced AMPKα and FOXO3A phosphorylation in the heart, attenuated the atrophy phenotype, and extended the mean lifespan of HGPS mice by ~21%, implying that targeting cardiac atrophy may be an approach to HGPS treatment.


Assuntos
Senilidade Prematura , Progéria , Humanos , Camundongos , Animais , Progéria/metabolismo , Coração , Dano ao DNA , Instabilidade Genômica , Proteínas Quinases Ativadas por AMP/genética , Lamina Tipo A/genética , Lamina Tipo A/metabolismo
6.
EMBO Rep ; 24(12): e56984, 2023 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-37955230

RESUMO

Aging is accompanied by a decreased DNA repair capacity, which might contribute to age-associated functional decline in multiple tissues. Disruption in hormone signaling, associated with reproductive organ dysfunction, is an early event of age-related tissue degeneration, but whether it impacts DNA repair in nonreproductive organs remains elusive. Using skin fibroblasts derived from healthy donors with a broad age range, we show here that the downregulation of expression of XRCC4, a factor involved in nonhomologous end-joining (NHEJ) repair, which is the dominant pathway to repair somatic double-strand breaks, is mediated through transcriptional mechanisms. We show that the androgen receptor (AR), whose expression is also reduced during aging, directly binds to and enhances the activity of the XRCC4 promoter, facilitating XRCC4 transcription and thus stabilizing the genome. We also demonstrate that dihydrotestosterone (DHT), a powerful AR agonist, restores XRCC4 expression and stabilizes the genome in different models of cellular aging. Moreover, DHT treatment reverses senescence-associated phenotypes, opening a potential avenue to aging interventions in the future.


Assuntos
Androgênios , Reparo do DNA por Junção de Extremidades , Androgênios/metabolismo , Quebras de DNA de Cadeia Dupla , Reparo do DNA/genética , Transdução de Sinais , Humanos
7.
Inorg Chem ; 63(24): 11406-11415, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38835144

RESUMO

Large and rapid lithium storage is hugely demanded for high-energy/power lithium-ion batteries; however, it is difficult to achieve these two indicators simultaneously. Sn-based materials with a (de)alloying mechanism show low working potential and high theoretical capacity, but the huge volume expansion and particle agglomeration of Sn restrict cyclic stability and rate capability. Herein, a soft-in-rigid concept was proposed and achieved by chemical scissoring where a soft Sn-S bond was chosen as chemical tailor to break the Ti-S bond to obtain a loose stacking structure of 1D chain-like Sn1.2Ti0.8S3. The in situ and ex situ (micro)structural characterizations demonstrate that the Sn-S bonds are reduced into Sn domains and such Sn disperses in the rigid Ti-S framework, thus relieving the volume expansion and particle agglomeration by chemical and physical shielding. Benefiting from the merits of large-capacity Sn with an alloying mechanism and high-rate TiS2 with an intercalation mechanism, the Sn1.2Ti0.8S3 anode offers a high specific capacity of 963.2 mA h g-1 at 0.1 A g-1 after 100 cycles and a reversible capacity of 250 mA h g-1 at 10 A g-1 after 3900 cycles. Such a strategy realized by chemical tailoring at the structural unit level would broaden the prospects for constructing joint high-capacity and high-rate LIB anodes.

8.
Nature ; 563(7729): 131-136, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30356214

RESUMO

Accurate repair of DNA double-stranded breaks by homologous recombination preserves genome integrity and inhibits tumorigenesis. Cyclic GMP-AMP synthase (cGAS) is a cytosolic DNA sensor that activates innate immunity by initiating the STING-IRF3-type I IFN signalling cascade1,2. Recognition of ruptured micronuclei by cGAS links genome instability to the innate immune response3,4, but the potential involvement of cGAS in DNA repair remains unknown. Here we demonstrate that cGAS inhibits homologous recombination in mouse and human models. DNA damage induces nuclear translocation of cGAS in a manner that is dependent on importin-α, and the phosphorylation of cGAS at tyrosine 215-mediated by B-lymphoid tyrosine kinase-facilitates the cytosolic retention of cGAS. In the nucleus, cGAS is recruited to double-stranded breaks and interacts with PARP1 via poly(ADP-ribose). The cGAS-PARP1 interaction impedes the formation of the PARP1-Timeless complex, and thereby suppresses homologous recombination. We show that knockdown of cGAS suppresses DNA damage and inhibits tumour growth both in vitro and in vivo. We conclude that nuclear cGAS suppresses homologous-recombination-mediated repair and promotes tumour growth, and that cGAS therefore represents a potential target for cancer prevention and therapy.


Assuntos
Núcleo Celular/metabolismo , Transformação Celular Neoplásica/patologia , Neoplasias/metabolismo , Neoplasias/patologia , Nucleotidiltransferases/metabolismo , Reparo de DNA por Recombinação , Transporte Ativo do Núcleo Celular , Adulto , Animais , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Núcleo Celular/enzimologia , Quebras de DNA de Cadeia Dupla , Dano ao DNA , Feminino , Células HEK293 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteínas de Neoplasias/metabolismo , Neoplasias/genética , Nucleotidiltransferases/deficiência , Fosforilação , Ftalazinas/farmacologia , Piperazinas/farmacologia , Poli(ADP-Ribose) Polimerase-1/antagonistas & inibidores , Poli(ADP-Ribose) Polimerase-1/metabolismo , Ligação Proteica/efeitos dos fármacos , Reparo de DNA por Recombinação/genética , Quinases da Família src/metabolismo
9.
J Biol Chem ; 298(5): 101861, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35339488

RESUMO

DNA polymerase eta (Pol η) is a eukaryotic member of the Y-family of DNA polymerase involved in translesion DNA synthesis and genome mutagenesis. Recently, several translesion DNA synthesis polymerases have been found to function in repair of DNA double-strand breaks (DSBs). However, the role of Pol η in promoting DSB repair remains to be well defined. Here, we demonstrated that Pol η could be targeted to etoposide (ETO)-induced DSBs and that depletion of Pol η in cells causes increased sensitivity to ETO. Intriguingly, depletion of Pol η also led to a nonhomologous end joining repair defect in a catalytic activity-independent manner. We further identified the scaffold protein Kap1 as a novel interacting partner of Pol η, the depletion of which resulted in impaired formation of Pol η and Rad18 foci after ETO treatment. Additionally, overexpression of Kap1 failed to restore Pol η focus formation in Rad18-deficient cells after ETO treatment. Interestingly, we also found that Kap1 bound to Rad18 in a Pol η-dependent manner, and moreover, depletion of Kap1 led to a significant reduction in Rad18-Pol η association, indicating that Kap1 forms a ternary complex with Rad18 and Pol η to stabilize Rad18-Pol η association. Our findings demonstrate that Kap1 could regulate the role of Pol η in ETO-induced DSB repair via facilitating Rad18 recruitment and stabilizing Rad18-Pol η association.


Assuntos
Reparo do DNA por Junção de Extremidades , Proteínas de Ligação a DNA , DNA Polimerase Dirigida por DNA , Ubiquitina-Proteína Ligases , Dano ao DNA , Reparo do DNA , Proteínas de Ligação a DNA/metabolismo , DNA Polimerase Dirigida por DNA/genética , DNA Polimerase Dirigida por DNA/metabolismo , Etoposídeo/farmacologia , Fatores de Transcrição/genética , Ubiquitina-Proteína Ligases/metabolismo
10.
Stem Cells ; 40(5): 493-507, 2022 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-35349711

RESUMO

DNA damage is assumed to accumulate in stem cells over time and their ability to withstand this damage and maintain tissue homeostasis is the key determinant of aging. Nonetheless, relatively few studies have investigated whether DNA damage does indeed accumulate in stem cells and whether this contributes to stem cell aging and functional decline. Here, we found that, compared with young mice, DNA double-strand breaks (DSBs) are reduced in the subventricular zone (SVZ)-derived neural stem cells (NSCs) of aged mice, which was achieved partly through the adaptive upregulation of Sirt1 expression and non-homologous end joining (NHEJ)-mediated DNA repair. Sirt1 deficiency abolished this effect, leading to stem cell exhaustion, olfactory memory decline, and accelerated aging. The reduced DSBs and the upregulation of Sirt1 expression in SVZ-derived NSCs with age may represent a compensatory mechanism that evolved to protect stem cells from excessive DNA damage, as well as mitigate memory loss and other stresses during aging.


Assuntos
Ventrículos Laterais , Células-Tronco Neurais , Sirtuína 1 , Envelhecimento/genética , Animais , DNA/metabolismo , Quebras de DNA de Cadeia Dupla , Reparo do DNA por Junção de Extremidades , Reparo do DNA , Ventrículos Laterais/metabolismo , Camundongos , Células-Tronco Neurais/metabolismo , Sirtuína 1/genética , Sirtuína 1/metabolismo
11.
Proc Natl Acad Sci U S A ; 117(42): 26356-26365, 2020 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-33020270

RESUMO

Understanding differences in DNA double-strand break (DSB) repair between tumor and normal tissues would provide a rationale for developing DNA repair-targeted cancer therapy. Here, using knock-in mouse models for measuring the efficiency of two DSB repair pathways, homologous recombination (HR) and nonhomologous end-joining (NHEJ), we demonstrated that both pathways are up-regulated in hepatocellular carcinoma (HCC) compared with adjacent normal tissues due to altered expression of DNA repair factors, including PARP1 and DNA-PKcs. Surprisingly, inhibiting PARP1 with olaparib abrogated HR repair in HCC. Mechanistically, inhibiting PARP1 suppressed the clearance of nucleosomes at DNA damage sites by blocking the recruitment of ALC1 to DSB sites, thereby inhibiting RPA2 and RAD51 recruitment. Importantly, combining olaparib with NU7441, a DNA-PKcs inhibitor that blocks NHEJ in HCC, synergistically suppressed HCC growth in both mice and HCC patient-derived-xenograft models. Our results suggest the combined inhibition of both HR and NHEJ as a potential therapy for HCC.


Assuntos
Carcinoma Hepatocelular/tratamento farmacológico , Cromonas/farmacologia , Morfolinas/farmacologia , Ftalazinas/farmacologia , Piperazinas/farmacologia , Animais , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Dano ao DNA , Reparo do DNA por Junção de Extremidades/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Proteínas de Ligação a DNA/metabolismo , Quimioterapia Combinada/métodos , Técnicas de Introdução de Genes , Recombinação Homóloga , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Camundongos , Camundongos Nus , Poli(ADP-Ribose) Polimerase-1/antagonistas & inibidores , Poli(ADP-Ribose) Polimerase-1/metabolismo , Reparo de DNA por Recombinação/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
12.
J Biomed Sci ; 29(1): 32, 2022 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-35546402

RESUMO

BACKGROUND: Aberrant DNA repair pathways contribute to malignant transformation or disease progression and the acquisition of drug resistance in multiple myeloma (MM); therefore, these pathways could be therapeutically exploited. Ribonucleotide reductase (RNR) is the rate-limiting enzyme for the biosynthesis of deoxyribonucleotides (dNTPs), which are essential for DNA replication and DNA damage repair. In this study, we explored the efficacy of the novel RNR inhibitor, 4-hydroxysalicylanilide (HDS), in myeloma cells and xenograft model. In addition, we assessed the clinical activity and safety of HDS in patients with MM. METHODS: We applied bioinformatic, genetic, and pharmacological approaches to demonstrate that HDS was an RNR inhibitor that directly bound to RNR subunit M2 (RRM2). The activity of HDS alone or in synergy with standard treatments was evaluated in vitro and in vivo. We also initiated a phase I clinical trial of single-agent HDS in MM patients (ClinicalTrials.gov: NCT03670173) to assess safety and efficacy. RESULTS: HDS inhibited the activity of RNR by directly targeting RRM2. HDS decreased the RNR-mediated dNTP synthesis and concomitantly inhibited DNA damage repair, resulting in the accumulation of endogenous unrepaired DNA double-strand breaks (DSBs), thus inhibiting MM cell proliferation and inducing apoptosis. Moreover, HDS overcame the protective effects of IL-6, IGF-1 and bone marrow stromal cells (BMSCs) on MM cells. HDS prolonged survival in a MM xenograft model and induced synergistic anti-myeloma activity in combination with melphalan and bortezomib. HDS also showed a favorable safety profile and demonstrated clinical activity against MM. CONCLUSIONS: Our study provides a rationale for the clinical evaluation of HDS as an anti-myeloma agent, either alone or in combination with standard treatments for MM. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03670173, Registered 12 September 2018.


Assuntos
Mieloma Múltiplo , Ribonucleotídeo Redutases , Quebras de DNA de Cadeia Dupla , Dano ao DNA , Reparo do DNA , Replicação do DNA , Humanos , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/genética , Ribonucleotídeo Redutases/genética , Ribonucleotídeo Redutases/metabolismo
13.
Nucleic Acids Res ; 48(16): 9181-9194, 2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32789493

RESUMO

The NAD+-dependent deacetylase and mono-ADP-ribosyl transferase SIRT6 stabilizes the genome by promoting DNA double strand break repair, thereby acting as a tumor suppressor. However, whether SIRT6 regulates nucleotide excision repair (NER) remains unknown. Here, we showed that SIRT6 was recruited to sites of UV-induced DNA damage and stimulated the repair of UV-induced DNA damage. Mechanistic studies further indicated that SIRT6 interacted with DDB2, the major sensor initiating global genome NER (GG-NER), and that the interaction was enhanced upon UV irradiation. SIRT6 deacetylated DDB2 at two lysine residues, K35 and K77, upon UV stress and then promoted DDB2 ubiquitination and segregation from chromatin, thereby facilitating downstream signaling. In addition, we characterized several SIRT6 mutations derived from melanoma patients. These SIRT6 mutants ablated the stimulatory effect of SIRT6 on NER and destabilized the genome due to (i) partial loss of enzymatic activity (P27S or H50Y), (ii) a nonsense mutation (R150*) or (iii) high turnover rates (G134W). Overall, we demonstrate that SIRT6 promotes NER by deacetylating DDB2, thereby preventing the onset of melanomagenesis.


Assuntos
Carcinogênese/genética , Dano ao DNA/genética , Proteínas de Ligação a DNA/genética , Melanoma/genética , Sirtuínas/genética , Carcinogênese/efeitos da radiação , Cromatina/genética , Cromatina/efeitos da radiação , Dano ao DNA/efeitos da radiação , Reparo do DNA/efeitos da radiação , Regulação da Expressão Gênica/efeitos da radiação , Células HeLa , Humanos , Melanoma/patologia , Mutação/efeitos da radiação , Ubiquitinação/efeitos da radiação , Raios Ultravioleta/efeitos adversos
14.
Acta Biochim Biophys Sin (Shanghai) ; 54(6): 828-835, 2022 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-35975605

RESUMO

DNA damage repair and innate immunity are two conserved mechanisms that both function in cellular stress responses. Recently, an increasing amount of evidence has uncovered the close relationship between these two ancient biological processes. Here, we review the classical function of factors involved in DNA repair, and especially double-strand break repair, in innate immunity; more importantly, we discuss the novel roles of DNA repair factors in regulating innate immunity and vice versa. In addition, we also review the roles of DNA repair, innate immunity and their crosstalk in human diseases, which suggest that these two pathways may be compelling targets for disease prevention and treatment.


Assuntos
Ácidos Nucleicos , DNA/genética , Quebras de DNA de Cadeia Dupla , Dano ao DNA , Reparo do DNA , Humanos
15.
FASEB J ; 34(8): 10966-10983, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32592217

RESUMO

Uterine leiomyomas (ULM) are a major public health issue contributing to high morbidity and poor pregnancy outcomes. However, its molecular pathogenesis is poorly understood. HMGA2-ULM is the second major subtype of human ULM and associates with large sizes, fast-growth, and high percentages of estrogen receptor α (ERα). As altered ERα expression plays a distinct role in ULM growth, here, we investigate a regulatory mechanism driving ULM growth via HMGA2 and ERα. We reveal a positive correlation of HMGA2 with ERα protein and demonstrate that HMGA2 promotes ULM cells proliferation via ERα. In addition, autophagy pathway and p62/SQSTM1 (a selective autophagy receptor) are found to participate in the regulation of HMGA2 and ERα. Moreover, HMGA2 suppresses the transcription of p62 by binding to its promoter, meanwhile, p62 interacts with ERα, and inhibition of p62 increases ERα expression and enhances cell viability in ULM, suggesting a novel mechanism of the HMGA2-p62-ERα axis in ULM proliferation. Notably, rapamycin, a familiar autophagy agonist, reduces ERα levels and the proliferation ability of ULM cells. This study demonstrates a causal role of the HMGA2-p62-ERα axis in preventing autophagy and increasing ERα expression in HMGA2-ULM. Therefore, blocking HMGA2-p62-ERα axis and targeting autophagy pathway establish a roadmap toward HMGA2-ULM medical treatment.


Assuntos
Proliferação de Células/fisiologia , Receptor alfa de Estrogênio/genética , Proteína HMGA2/genética , Leiomioma/genética , Proteína Sequestossoma-1/genética , Neoplasias Uterinas/genética , Adulto , Autofagia/fisiologia , Sobrevivência Celular/genética , Células Cultivadas , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Células HEK293 , Humanos , Leiomioma/patologia , Pessoa de Meia-Idade , Regiões Promotoras Genéticas/genética , Transdução de Sinais/genética , Transcrição Gênica/genética , Neoplasias Uterinas/patologia , Útero/patologia
16.
Nucleic Acids Res ; 47(16): 8563-8580, 2019 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-31291457

RESUMO

Creating access to DNA double-strand break (DSB) sites in the chromatin context is an essential step during the repair process, but much remains to be determined about its regulatory mechanisms. Here, using a novel reporter cassette for simultaneous detection of homologous recombination (HR) and nonhomologous end joining (NHEJ) at the same chromosomal site, we report that the efficiency of HR but not NHEJ negatively correlates with nucleosome density. We demonstrate that PARP1 is required for HR by modulating nucleosome density at damage sites. Mechanistic studies indicate that the ATPase domain of BRG1 and the ZnF domain of SIRT1 interact with poly-ADP ribose (PAR) in response to DNA damage, and are responsible for bringing the two factors to broken DNA ends. At DNA damage sites, BRG1 and SIRT1 physically interact, whereupon SIRT1 deacetylates BRG1 at lysine residues 1029 and 1033, stimulating its ATPase activity to remodel chromatin and promote HR.


Assuntos
DNA Helicases/genética , DNA/genética , Proteínas Nucleares/genética , Nucleossomos/metabolismo , Poli(ADP-Ribose) Polimerase-1/genética , Reparo de DNA por Recombinação , Sirtuína 1/genética , Fatores de Transcrição/genética , Sítios de Ligação , Linhagem Celular , Linhagem Celular Tumoral , Cloroquina/farmacologia , DNA/metabolismo , Quebras de DNA de Cadeia Dupla , Reparo do DNA por Junção de Extremidades , DNA Helicases/metabolismo , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Regulação da Expressão Gênica , Genes Reporter , Células HEK293 , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Proteínas Nucleares/metabolismo , Nucleossomos/química , Nucleossomos/efeitos dos fármacos , Fenantrenos/farmacologia , Ftalazinas/farmacologia , Piperazinas/farmacologia , Poli(ADP-Ribose) Polimerase-1/antagonistas & inibidores , Poli(ADP-Ribose) Polimerase-1/metabolismo , Poli Adenosina Difosfato Ribose/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Sirtuína 1/metabolismo , Fatores de Transcrição/metabolismo
17.
J Cell Sci ; 131(12)2018 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-29760279

RESUMO

Dysregulation of the homeostatic balance of histone H3 di- and tri-methyl lysine 27 (H3K27me2/3) levels caused by the mis-sense mutation of histone H3 (H3K27M) is reported to be associated with various types of cancers. In this study, we found that reduction in H3K27me2/3 caused by H3.1K27M, a mutation of H3 variants found in patients with diffuse intrinsic pontine glioma (DIPG), dramatically attenuated the presence of 53BP1 (also known as TP53BP1) foci and the capability of non-homologous end joining (NHEJ) in human dermal fibroblasts. H3.1K27M mutant cells showed increased rates of genomic insertions/deletions and copy number variations, as well as an increase in p53-dependent apoptosis. We further showed that both hypo-H3K27me2/3 and H3.1K27M interacted with FANCD2, a central player in the choice of DNA repair pathway. H3.1K27M triggered the accumulation of FANCD2 on chromatin, suggesting an interaction between H3.1K27M and FANCD2. Interestingly, knockdown of FANCD2 in H3.1K27M cells recovered the number of 53BP1-positive foci, NHEJ efficiency and apoptosis rate. Although these findings in HDF cells may differ from the endogenous regulation of the H3.1K27M mutant in the specific tumor context of DIPG, our results suggest a new model by which H3K27me2/3 facilitates NHEJ and the maintenance of genome stability.This article has an associated First Person interview with the first author of the paper.


Assuntos
Cromatina/metabolismo , Reparo do DNA por Junção de Extremidades , Enzimas Reparadoras do DNA/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteína do Grupo de Complementação D2 da Anemia de Fanconi/metabolismo , Histonas/metabolismo , Neoplasias do Tronco Encefálico/genética , Neoplasias do Tronco Encefálico/metabolismo , Linhagem Celular , Cromatina/genética , Reparo do DNA , Enzimas Reparadoras do DNA/genética , Proteínas de Ligação a DNA/genética , Proteína do Grupo de Complementação D2 da Anemia de Fanconi/genética , Fibroblastos , Instabilidade Genômica , Glioma/genética , Glioma/metabolismo , Células HEK293 , Histonas/genética , Humanos , Metilação , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/genética , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo
18.
Nat Chem Biol ; 14(12): 1118-1126, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30374165

RESUMO

SIRT6, a member of the SIRT deacetylase family, is responsible for deacetylation of histone H3 Nε-acetyl-lysines 9 (H3K9ac) and 56 (H3K56ac). As a tumor suppressor, SIRT6 has frequently been found to have low expression in various cancers. Here, we report the identification of MDL-800, a selective SIRT6 activator. MDL-800 increased the deacetylase activity of SIRT6 by up to 22-fold via binding to an allosteric site; this interaction led to a global decrease in H3K9ac and H3K56ac levels in human hepatocellular carcinoma (HCC) cells. Consequently, MDL-800 inhibited the proliferation of HCC cells via SIRT6-driven cell-cycle arrest and was effective in a tumor xenograft model. Together, these data demonstrate that pharmacological activation of SIRT6 is a potential therapeutic approach for the treatment of HCC. MDL-800 is a first-in-class small-molecule cellular SIRT6 activator that can be used to physiologically and pathologically investigate the roles of SIRT6 deacetylation.


Assuntos
Antineoplásicos/farmacologia , Benzoatos/farmacologia , Ensaios de Triagem em Larga Escala/métodos , Sirtuínas/metabolismo , Compostos de Enxofre/farmacologia , Regulação Alostérica , Sítio Alostérico , Animais , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular , Linhagem Celular Tumoral , Cristalografia por Raios X , Feminino , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Camundongos Endogâmicos BALB C , Simulação de Dinâmica Molecular , Terapia de Alvo Molecular , Sirtuínas/química , Sirtuínas/genética , Ensaios Antitumorais Modelo de Xenoenxerto
19.
Nature ; 499(7458): 346-9, 2013 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-23783513

RESUMO

The naked mole rat (Heterocephalus glaber) displays exceptional longevity, with a maximum lifespan exceeding 30 years. This is the longest reported lifespan for a rodent species and is especially striking considering the small body mass of the naked mole rat. In comparison, a similarly sized house mouse has a maximum lifespan of 4 years. In addition to their longevity, naked mole rats show an unusual resistance to cancer. Multi-year observations of large naked mole-rat colonies did not detect a single incidence of cancer. Here we identify a mechanism responsible for the naked mole rat's cancer resistance. We found that naked mole-rat fibroblasts secrete extremely high-molecular-mass hyaluronan (HA), which is over five times larger than human or mouse HA. This high-molecular-mass HA accumulates abundantly in naked mole-rat tissues owing to the decreased activity of HA-degrading enzymes and a unique sequence of hyaluronan synthase 2 (HAS2). Furthermore, the naked mole-rat cells are more sensitive to HA signalling, as they have a higher affinity to HA compared with mouse or human cells. Perturbation of the signalling pathways sufficient for malignant transformation of mouse fibroblasts fails to transform naked mole-rat cells. However, once high-molecular-mass HA is removed by either knocking down HAS2 or overexpressing the HA-degrading enzyme, HYAL2, naked mole-rat cells become susceptible to malignant transformation and readily form tumours in mice. We speculate that naked mole rats have evolved a higher concentration of HA in the skin to provide skin elasticity needed for life in underground tunnels. This trait may have then been co-opted to provide cancer resistance and longevity to this species.


Assuntos
Transformação Celular Neoplásica/metabolismo , Ácido Hialurônico/metabolismo , Sequência de Aminoácidos , Animais , Proliferação de Células , Células Cultivadas , Inibição de Contato , Resistência à Doença , Fibroblastos/metabolismo , Glucuronosiltransferase/química , Cobaias , Humanos , Hialuronan Sintases , Camundongos , Ratos-Toupeira , Dados de Sequência Molecular
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