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1.
BMC Biol ; 19(1): 242, 2021 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-34763695

RESUMO

BACKGROUND: Proteostasis unbalance and mitochondrial dysfunction are two hallmarks of aging. While the chaperone folds and activates its clients, it is the cochaperone that determines the specificity of the clients. Ids2 is an HSP90's cochaperone controlling mitochondrial functions, but no in vivo clients of Ids2 have been reported yet. RESULTS: We performed a screen of the databases of HSP90 physical interactors, mitochondrial components, and mutants with respiratory defect, and identified Atp3, a subunit of the complex V ATP synthase, as a client of Ids2. Deletion of IDS2 destabilizes Atp3, and an α-helix at the middle region of Ids2 recruits Atp3 to the folding system. Shortage of Ids2 or Atp3 leads to the loss of mitochondrial DNA. The intermembrane space protease Yme1 is critical to maintaining the Atp3 protein level. Moreover, Ids2 is highly induced when cells carry out oxidative respiration. CONCLUSIONS: These findings discover a cochaperone essentially for maintaining the stability of mitochondrial DNA and the proteostasis of the electron transport chain-crosstalk between two hallmarks of aging.


Assuntos
DNA Mitocondrial , Proteínas de Choque Térmico HSP90 , Trifosfato de Adenosina , DNA Mitocondrial/genética , Proteínas de Choque Térmico HSP90/genética , Humanos , Mitocôndrias , Chaperonas Moleculares/genética
2.
Infect Dis Ther ; 10(4): 2661-2675, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34623624

RESUMO

INTRODUCTION: Histopathological characteristics of cytomegalovirus (CMV) lymphadenitis have been well described. Rare studies have reported the immune status and clinical features. Clinically, experts believed that CMV lymphadenitis develops in immunocompromised and immunocompetent patients. Infectious mononucleosis (IM)-like syndrome is the most well-known clinical presentation. METHODS: We reviewed archived CMV immunohistochemical stains on lymphoid tissues. The clinicopathological features of CMV-positive cases were studied. RESULTS: For lymph nodes, we detected CMV in 29% (5/17) allogeneic peripheral blood hematopoietic stem cell transplantation (PBSCT) recipients, 29% (4/14) post-autologous PBSCT patients, 13% (6/47) patients treated with intravenous chemotherapy, and 9% (9/96) immunocompetent patients. We detected CMV in 7% (2/24) of tonsils but not in the nasopharynx, tongue base, or spleen specimens. The patients with iatrogenic immunodeficiency ranged from 37 to 76 years old. CMV infections developed a few years after lymphoma treatment (median duration after allogeneic PBSCT, 932 days; after autologous PBSCT, 370 days; and after chemotherapy, 626 days). The most common clinical presentation was neck mass (13/25, 42%), followed by asymptomatic image finding (10/25, 40%). Positron emission tomography/computed tomography (PET/CT) scan showed increased uptake compared to the liver in all patients (11/11, 100%). Of 10 lymphoma patients, 8 (80%) had a Deauville score of 4-5; they accounted for 30% (8/27) of lymphoma patients with false-positive PET/CT scan results. All cases were self-limiting. 96% (23/25) cases had Epstein-Barr virus coinfection, and EBER-positive cells were predominantly in a few germinal centers. CONCLUSIONS: Cytomegalovirus (CMV) lymphadenitis and tonsillitis were subclinical infections, not primary CMV infection with IM-like syndrome. The lymphadenopathy typically developed a few years after lymphoma treatments in the middle-aged and the elderly. The lesions mimicked lymphoma relapse in PET scans. Therefore, recognizing CMV infection in lymphoid tissues is of clinical importance.

3.
J Biomed Sci ; 28(1): 65, 2021 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-34565360

RESUMO

BACKGROUND: Heterozygous pathogenic variants in STUB1 are implicated in autosomal dominant spinocerebellar ataxia type 48 (SCA48), which is a rare familial ataxia disorder. We investigated the clinical, genetic and functional characteristics of STUB1 mutations identified from a Taiwanese ataxia cohort. METHODS: We performed whole genome sequencing in a genetically undiagnosed family with an autosomal dominant ataxia syndrome. Further Sanger sequencing of all exons and intron-exon boundary junctions of STUB1 in 249 unrelated patients with cerebellar ataxia was performed. The pathogenicity of the identified novel STUB1 variant was investigated. RESULTS: We identified a novel heterozygous frameshift variant, c.832del (p.Glu278fs), in STUB1 in two patients from the same family. This rare mutation is located in the U-box of the carboxyl terminus of the Hsc70-interacting protein (CHIP) protein, which is encoded by STUB1. Further in vitro experiments demonstrated that this novel heterozygous STUB1 frameshift variant impairs the CHIP protein's activity and its interaction with the E2 ubiquitin ligase, UbE2D1, leading to neuronal accumulation of tau and α-synuclein, caspase-3 activation, and promoting cellular apoptosis through a dominant-negative pathogenic effect. The in vivo study revealed the influence of the CHIP expression level on the differentiation and migration of cerebellar granule neuron progenitors during cerebellar development. CONCLUSIONS: Our findings provide clinical, genetic, and a mechanistic insight linking the novel heterozygous STUB1 frameshift mutation at the highly conserved U-box domain of CHIP as the cause of autosomal dominant SCA48. Our results further stress the importance of CHIP activity in neuronal protein homeostasis and cerebellar functions.


Assuntos
Mutação da Fase de Leitura , Ataxias Espinocerebelares/genética , Ubiquitina-Proteína Ligases/genética , Adulto , Idoso , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Taiwan , Ubiquitina-Proteína Ligases/metabolismo
4.
Aging (Albany NY) ; 13(7): 10490-10516, 2021 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-33820871

RESUMO

Telomere length homeostasis is essential for maintaining genomic stability and cancer proliferation. Telomerase-negative cancer cells undergo recombination-mediated alternative lengthening of telomeres. Telomeres associate with the nuclear envelope through the shelterin RAP1 and nuclear envelope SUN1 proteins. However, how the associations between telomeres and the nuclear envelope affect the progression of telomere recombination is not understood. Here, we show that telomere anchorage might inhibit telomere-telomere recombination. SUN1 depletion stimulates the formation of alternative lengthening of telomeres-associated promyelocytic leukemia bodies in ALT cells. In contrast, overexpression of a telomere-nuclear envelope-tethering chimera protein, RAP1-SUN1, suppresses APB formation. Moreover, inhibition of this nuclear envelope attachment alleviates the requirement of TOP3α for resolving the supercoiling pressure during telomere recombination. A coimmunoprecipitation assay revealed that the SUN1 N-terminal nucleoplasmic domain interacts with the RAP1 middle coil domain, and phosphorylation-mimetic mutations in RAP1 inhibit this interaction. However, abolishing the RAP1-SUN1 interaction does not hinder APB formation, which hints at the existence of another SUN1-dependent telomere anchorage pathway. In summary, our results reveal an inhibitory role of telomere-nuclear envelope association in telomere-telomere recombination and imply the presence of redundant pathways for the telomere-nuclear envelope association in ALT cells.


Assuntos
Proteínas de Membrana/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Membrana Nuclear/metabolismo , Proteínas Nucleares/metabolismo , Homeostase do Telômero/fisiologia , Proteínas de Ligação a Telômeros/metabolismo , Linhagem Celular Tumoral , Humanos , Proteína da Leucemia Promielocítica/metabolismo
5.
Aging (Albany NY) ; 12(20): 20702-20727, 2020 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-33085644

RESUMO

Parkinson's disease (PD) is a common neurodegenerative disorder with the pathological hallmark of α-synuclein aggregation. Dysregulation of α-synuclein homeostasis caused by aging, genetic, and environmental factors underlies the pathogenesis of PD. While chaperones are essential for proteostasis, whether modulation of cochaperones may participate in PD formation has not been fully characterized. Here, we assessed the expression of several HSP70- and HSP90-related factors under various stresses and found that BAG5 expression is distinctively elevated in etoposide- or H2O2-treated SH-SY5Y cells. Stress-induced p53 binds to the BAG5 promoter directly to stimulate BAG5. Induced BAG5 binds α-synuclein and HSP70 in both cell cultures and brain lysates from PD patients. Overexpressed BAG5 may result in the loss of its ability to promote HSP70. Importantly, α-synuclein aggregation in SH-SY5Y cells requires BAG5. BAG5 expression is also detected in transgenic SNCA mutant mice and in PD patients. Together, our data reveal stress-induced p53-BAG5-HSP70 regulation that provides a potential therapeutic angle for PD.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Doença de Parkinson/genética , Proteína Supressora de Tumor p53/fisiologia , alfa-Sinucleína/fisiologia , Animais , Células Cultivadas , Modelos Animais de Doenças , Regulação da Expressão Gênica , Humanos , Camundongos
6.
J Cancer Res Clin Oncol ; 146(7): 1671-1676, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32333143

RESUMO

BACKGROUND: DNA topoisomerase and telomerase enzymes are popular targets of several anti-tumor drugs. Smooth proceeding of telomeric recombination requires Topoisomerase II (Top2), which is involved in telomere-telomere recombination through functioning in relaxation of positive supercoils among the cells adopting telomerase-independent Alternative lengthening of telomere (ALT) pathway. Most of the inhibitors reported so far have been designed to targetsolely telomerase-positive cells, which can potentially lead to therapeutic failure because tumor cells treated with telomerase inhibitors can activate the ALT pathway for telomere maintenance. Knowing that ALT cells are more sensitive against a Top2 inhibitor, ICRF-93 agent, compared to telomerase-positive cells, we analyzed two selected ellipticine derivatives that we recently reported as TopII-targeting compounds, to assess their effects on the formation of DNA breaks and suppression of ALT pathway. METHODS: Cell viability, Comet, C-Circle assays, dot blot, immunofluorescence staining, and telomere fluorescence in situ hybridization (FISH) staining were used for determining the effect of the compounds on ALT status of tumor cells. RESULTS AND CONCLUSIONS: Treatment of ALT cells with ellipticine derivatives resulted in the formation of DNA breaks and suppression of ALT-associated phenotypes in vitro. Our results will contribute to the development of therapeutic strategies combining telomerase and ALT pathway inhibitors.


Assuntos
Antineoplásicos/farmacologia , Elipticinas/farmacologia , Telomerase/genética , Homeostase do Telômero/efeitos dos fármacos , Inibidores da Topoisomerase II/farmacologia , Antineoplásicos/química , Linhagem Celular , Elipticinas/química , Imunofluorescência , Humanos , Hibridização in Situ Fluorescente
7.
Elife ; 72018 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-30516470

RESUMO

Aging is an intricate phenomenon associated with the gradual loss of physiological functions, and both nutrient sensing and proteostasis control lifespan. Although multiple approaches have facilitated the identification of candidate genes that govern longevity, the molecular mechanisms that link aging pathways are still elusive. Here, we conducted a quantitative mass spectrometry screen and identified all phosphorylation/dephosphorylation sites on yeast proteins that significantly responded to calorie restriction, a well-established approach to extend lifespan. Functional screening of 135 potential regulators uncovered that Ids2 is activated by PP2C under CR and inactivated by PKA under glucose intake. ids2Δ or ids2 phosphomimetic cells displayed heat sensitivity and lifespan shortening. Ids2 serves as a co-chaperone to form a complex with Hsc82 or the redundant Hsp82, and phosphorylation impedes its association with chaperone HSP90. Thus, PP2C and PKA may orchestrate glucose sensing and protein folding to enable cells to maintain protein quality for sustained longevity.


Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/genética , Regulação Fúngica da Expressão Gênica , Glucose/deficiência , Proteínas de Choque Térmico HSP90/genética , Fosfoproteínas Fosfatases/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Glucose/farmacologia , Proteínas de Choque Térmico HSP90/metabolismo , Resposta ao Choque Térmico , Temperatura Alta , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Fosfoproteínas Fosfatases/metabolismo , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Fosforilação , Dobramento de Proteína , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo
8.
Nucleic Acids Res ; 45(18): 10492-10503, 2017 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-28985359

RESUMO

Telomerase is highly expressed in cancer and embryonic stem cells (ESCs) and implicated in controlling genome integrity, cancer formation and stemness. Previous studies identified that Krüppel-like transcription factor 4 (KLF4) activates telomerase reverse transcriptase (TERT) expression and contributes to the maintenance of self-renewal in ESCs. However, little is known about how KLF4 regulates TERT expression. Here, we discover poly(ADP-ribose) polymerase 1 (PARP1) as a novel KLF4-interacting partner. Knockdown of PARP1 reduces TERT expression and telomerase activity not only in cancer cells, but also in human and mouse ESCs. Recruitment of KLF4 to TERT promoter is reduced in PARP1-suppressed cells. The poly(ADP-ribose) polymerase activity is dispensable, while the oligo(ADP-ribose) polymerase activity is required for the PARP1- and KLF4-mediated TERT activation. Repression of Parp1 in mouse ESCs decreases expression of pluripotent markers and induces differentiation. These results suggest that PARP1 recruits KLF4 to activate telomerase expression and stem cell pluripotency, indicating a positive regulatory role of the PARP1-KLF4 complex in telomerase expression in cancer and stem cells.


Assuntos
Células-Tronco Embrionárias/metabolismo , Fatores de Transcrição Kruppel-Like/fisiologia , Neoplasias/genética , Poli(ADP-Ribose) Polimerase-1/fisiologia , Telomerase/genética , Animais , Diferenciação Celular/genética , Células Cultivadas , Embrião de Mamíferos , Células-Tronco Embrionárias/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Humanos , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , Neoplasias/patologia , Poli(ADP-Ribose) Polimerase-1/metabolismo , Telomerase/metabolismo
9.
Nat Commun ; 8(1): 56, 2017 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-28676626

RESUMO

Upon environmental changes, proliferating cells delay cell cycle to prevent further damage accumulation. Yeast Cip1 is a Cdk1 and Cln2-associated protein. However, the function and regulation of Cip1 are still poorly understood. Here we report that Cip1 expression is co-regulated by the cell-cycle-mediated factor Mcm1 and the stress-mediated factors Msn2/4. Overexpression of Cip1 arrests cell cycle through inhibition of Cdk1-G1 cyclin complexes at G1 stage and the stress-activated protein kinase-dependent Cip1 T65, T69, and T73 phosphorylation may strengthen the Cip1and Cdk1-G1 cyclin interaction. Cip1 accumulation mainly targets Cdk1-Cln3 complex to prevent Whi5 phosphorylation and inhibit early G1 progression. Under osmotic stress, Cip1 expression triggers transient G1 delay which plays a functionally redundant role with another hyperosmolar activated CKI, Sic1. These findings indicate that Cip1 functions similarly to mammalian p21 as a stress-induced CDK inhibitor to decelerate cell cycle through G1 cyclins to cope with environmental stresses.A G1 cell cycle regulatory kinase Cip1 has been identified in budding yeast but how this is regulated is unclear. Here the authors identify cell cycle (Mcm1) and stress-mediated (Msn 2/4) transcription factors as regulating Cip1, causing stress induced CDK inhibition and delay in cell cycle progression.


Assuntos
Ciclo Celular , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Ciclinas/metabolismo , Regulação Fúngica da Expressão Gênica , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteína 1 de Manutenção de Minicromossomo/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Pressão Osmótica , Saccharomyces cerevisiae , Estresse Fisiológico , Fatores de Transcrição/metabolismo
10.
Sci Rep ; 7(1): 3842, 2017 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-28630472

RESUMO

SMYD3 is a methyltransferase highly expressed in many types of cancer. It usually functions as an oncogenic protein to promote cell cycle, cell proliferation, and metastasis. Here, we show that SMYD3 modulates another hallmark of cancer, DNA repair, by stimulating transcription of genes involved in multiple steps of homologous recombination. Deficiency of SMYD3 induces DNA-damage hypersensitivity, decreases levels of repair foci, and leads to impairment of homologous recombination. Moreover, the regulation of homologous recombination-related genes is via the methylation of H3K4 at the target gene promoters. These data imply that, besides its reported oncogenic abilities, SMYD3 may maintain genome integrity by ensuring expression levels of HR proteins to cope with the high demand of restart of stalled replication forks in cancers.


Assuntos
Regulação da Expressão Gênica , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/metabolismo , Recombinação Homóloga , Linhagem Celular Tumoral , Dano ao DNA , Reparo do DNA , Técnicas de Silenciamento de Genes , Humanos , Metilação , Modelos Biológicos
11.
Nucleic Acids Res ; 45(14): 8314-8328, 2017 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-28575419

RESUMO

Telomere homeostasis is controlled by both telomerase machinery and end protection. Telomere shortening induces DNA damage sensing kinases ATM/ATR for telomerase recruitment. Yet, whether telomere shortening also governs end protection is poorly understood. Here we discover that yeast ATM/ATR controls end protection. Rap1 is phosphorylated by Tel1 and Mec1 kinases at serine 731, and this regulation is stimulated by DNA damage and telomere shortening. Compromised Rap1 phosphorylation hampers the interaction between Rap1 and its interacting partner Rif1, which thereby disturbs the end protection. As expected, reduction of Rap1-Rif1 association impairs telomere length regulation and increases telomere-telomere recombination. These results indicate that ATM/ATR DNA damage checkpoint signal contributes to telomere protection by strengthening the Rap1-Rif1 interaction at short telomeres, and the checkpoint signal oversees both telomerase recruitment and end capping pathways to maintain telomere homeostasis.


Assuntos
Retroalimentação Fisiológica , Homeostase do Telômero/genética , Encurtamento do Telômero/genética , Telômero/genética , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Western Blotting , Dano ao DNA , Modelos Genéticos , Mutação , Fosforilação , Ligação Proteica , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Serina/genética , Serina/metabolismo , Proteínas Reguladoras de Informação Silenciosa de Saccharomyces cerevisiae/genética , Proteínas Reguladoras de Informação Silenciosa de Saccharomyces cerevisiae/metabolismo , Telômero/metabolismo , Proteínas de Ligação a Telômeros/genética , Proteínas de Ligação a Telômeros/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Técnicas do Sistema de Duplo-Híbrido
12.
Food Sci Nutr ; 5(2): 197-204, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28265354

RESUMO

In both tumor and yeast cells that lack telomerase, telomeres are maintained via an alternative recombination mechanism. In this study, we tested genistein, a potential TOP2 inhibitor required for telomere-telomere recombination, on the repression of telomere-telomere recombination. Genistein on the repression of type II recombination on a tlc1 yeast strain was examined by the telomeric DNA structures using Southern blot analysis. Telomere patterns of freshly dissected tlc1 spores containing an empty plasmid (pYES2) or a yeast TOP2 (yTOP2) plasmid were analyzed. The results indicated that the reintroduction of TOP2 recovered the type II pattern, implying genistein in the blockage of type II survivors in the tlc1 strain. The effects of genistein on both tlc1 and tlc1 rad 51 strains in liquid and solid mediums were also examined. Finally, treatment of 10 µmol/L of genistein showed inhibitory effect on the growth of telomerase-negative U2OS alternative lengthening of telomere (ALT) cells, but not in telomerase-positive HCT116 cells. These results provide evidences that the inhibitory effects of genistein on telomerase-negative cells depend on type II recombination pathway in yeast and the ALT pathway in human tumors.

13.
Nat Commun ; 7: 13644, 2016 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-27934968

RESUMO

Intratumoural hypoxia induces HIF-1α and promotes tumour progression, metastasis and treatment resistance. HIF-1α stability is regulated by VHL-E3 ligase-mediated ubiquitin-dependent degradation; however, the hypoxia-regulated deubiquitinase that stabilizes HIF-1α has not been identified. Here we report that HAUSP (USP7) deubiquitinase deubiquitinates HIF-1α to increase its stability, induce epithelial-mesenchymal transition and promote metastasis. Hypoxia induces K63-linked polyubiquitinated HAUSP at lysine 443 to enhance its functions. Knockdown of HAUSP decreases acetylation of histone 3 lysine 56 (H3K56Ac). K63-polyubiquitinated HAUSP interacts with a ubiquitin receptor CBP to specifically mediate H3K56 acetylation. ChIP-seq analysis of HAUSP and HIF-1α binding reveals two motifs responsive to hypoxia. HectH9 is the E3 ligase for HAUSP and a prognostic marker together with HIF-1α. This report demonstrates that hypoxia-induced K63-polyubiquitinated HAUSP deubiquitinates HIF-1α and causes CBP-mediated H3K56 acetylation on HIF-1α target gene promoters to promote EMT/metastasis, further defining HAUSP as a therapeutic target in hypoxia-induced tumour progression.


Assuntos
Histonas/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Oxigênio/metabolismo , Peptidase 7 Específica de Ubiquitina/metabolismo , Acetilação , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal/fisiologia , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Modelos Moleculares , Fragmentos de Peptídeos , Regiões Promotoras Genéticas , Conformação Proteica , Sialoglicoproteínas , Espectrometria de Massas em Tandem , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Peptidase 7 Específica de Ubiquitina/genética , Ubiquitinação
14.
Cancer Res ; 76(20): 6043-6053, 2016 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-27569210

RESUMO

SMYD3 methyltransferase is nearly undetectable in normal human tissues but highly expressed in several cancers, including breast cancer, although its contributions to pathogenesis in this setting are unclear. Here we report that histone H2A.Z.1 is a substrate of SMYD3 that supports malignancy. SMYD3-mediated dimethylation of H2A.Z.1 at lysine 101 (H2A.Z.1K101me2) increased stability by preventing binding to the removal chaperone ANP32E and facilitating its interaction with histone H3. Moreover, a microarray analysis identified cyclin A1 as a target coregulated by SMYD3 and H2A.Z.1K101me2. The colocalization of SMYD3 and H2A.Z.1K101me2 at the promoter of cyclin A1 activated its expression and G1-S progression. Enforced expression of cyclin A1 in cells containing mutant H2A.Z.1 rescued tumor formation in a mouse model. Our findings suggest that SMYD3-mediated H2A.Z.1K101 dimethylation activates cyclin A1 expression and contributes to driving the proliferation of breast cancer cells. Cancer Res; 76(20); 6043-53. ©2016 AACR.


Assuntos
Neoplasias da Mama/patologia , Ciclo Celular , Proliferação de Células , Histona-Lisina N-Metiltransferase/fisiologia , Histonas/metabolismo , Animais , Linhagem Celular Tumoral , Ciclina A1/genética , Feminino , Humanos , Metilação , Camundongos
15.
Cancer Lett ; 378(1): 59-67, 2016 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-27177472

RESUMO

Intratumoral hypoxia induces epithelial-mesenchymal transition and promotes cancer metastasis. MicroRNAs (miRNAs) are endogenous, single-strand RNA molecules that regulate gene expression. MiRNAs control cell growth, proliferation, differentiation and cell death and may function as oncogenes or tumor suppressors. HDAC3 and SENP1 are two molecules involved in hypoxia-induced EMT and HIF-1α stability, respectively. In this report, we show that miR-1236 plays a critical role in hypoxia-induced EMT and metastasis. MiRNA prediction programs TargetScan and miRanda show that miR-1236 may target HDAC3 and SENP1. MiR-1236 represses the luciferase activity of reporter constructs containing 3'UTR of HDAC3 and SENP1 as well as the expression levels of HDAC3 and SENP1. MiR-1236 abolishes hypoxia-induced EMT and inhibits migration and invasion activity of tumor cells. Hypoxia represses miR-1236 expression. The promoter region of miR-1236 is identified as the NELFE promoter. Twist1, an EMT regulator activated by hypoxia/HIF-1α, is shown to repress the reporter construct driven by the NELFE promoter. The binding site of Twist1 in the NELFE promoter is identified and chromatin immunoprecipitation assays show the direct binding of Twist1 to this site. Overexpression or knockdown of Twist1 in stable cell lines shows the inverse correlation between Twist1 and miR-1236 expression. These results identify a miRNA that regulates hypoxia-induced EMT and metastasis through repressing HDAC3 and SENP1 expression and present a regulatory network that involves many key players in hypoxia-induced EMT.


Assuntos
Movimento Celular , Cisteína Endopeptidases/metabolismo , Transição Epitelial-Mesenquimal , Histona Desacetilases/metabolismo , MicroRNAs/metabolismo , Neoplasias/enzimologia , Regiões 3' não Traduzidas , Sítios de Ligação , Biologia Computacional , Cisteína Endopeptidases/genética , Regulação para Baixo , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Histona Desacetilases/genética , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Células MCF-7 , MicroRNAs/genética , Invasividade Neoplásica , Neoplasias/genética , Neoplasias/patologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Regiões Promotoras Genéticas , Interferência de RNA , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transfecção , Hipóxia Tumoral , Proteína 1 Relacionada a Twist/genética , Proteína 1 Relacionada a Twist/metabolismo
16.
Oncotarget ; 7(12): 13917-31, 2016 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-26871601

RESUMO

Cancer stem cells, also known as cancer initiating cells (CICs), are considered to be responsible for tumor growth and chemoresistance. Different hypotheses have been proposed to explain the origin of CICs, including mutations in adult stem/progenitor cells or the acquisition of stem-like characteristics in differentiated cells; however, studies have yielded conflicting identification for CICs and have little information for the origin to generate CICs. Part of the difficulty in identifying CICs may stem from the fact that the CICs studied have been largely derived from cancer cell lines or well-developed tumors. In previous studies, we have reported the enrichment of mouse pulmonary stem/progenitor cells (mPSCs) by using serum-free primary selection culture followed by FACS isolation using the coxsackievirus/adenovirus receptor (CAR) as the positive selection marker. Here, we demonstrated that overexpression of the pluripotent transcription factor Oct-4 is sufficient to induce CAR+/mPSCs transformation, which we name CAR+/mPSCsOct-4_hi. These transformed cells possess cancer initiating and chemoresistance potential, as well as exhibiting remarkable expression of certain proangiogenic factors, including angiopoietins (ANGs) and VEGF, and enhanced angiogenic potential. Moreover, CAR+/mPSCsOct-4_hi actively participated in tumor blood vessel formation and triggered a novel angiogenic mechanism, the angiopoietins/Tie2 signaling pathway. These study provide critical evidence supporting the possible origin to generate CICs, and help elucidate the pathways responsible for CICs-mediated blood vessel formation.


Assuntos
Biomarcadores Tumorais/metabolismo , Carcinogênese/patologia , Neoplasias Pulmonares/irrigação sanguínea , Neoplasias Pulmonares/patologia , Células-Tronco Neoplásicas/patologia , Neovascularização Patológica/patologia , Fator 3 de Transcrição de Octâmero/metabolismo , Adenocarcinoma/irrigação sanguínea , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Animais , Apoptose , Carcinogênese/metabolismo , Proliferação de Células , Humanos , Neoplasias Pulmonares/metabolismo , Masculino , Camundongos , Camundongos SCID , Células-Tronco Neoplásicas/metabolismo , Neovascularização Patológica/metabolismo , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
18.
Int J Biochem Cell Biol ; 64: 229-38, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25959252

RESUMO

Hypoxia-inducible factor (HIF) is a heterodimer transcription factor complex that monitors the cellular response to the oxygen levels in cells. Hypoxia-inducible factor-1α (HIF-1α) has been shown to be stabilized by ionizing radiation (IR) and its stabilization promotes tumor progression and metastasis. Nijmegen breakage syndrome protein 1 (NBS1), a component of the MRE11-RAD50-NBS1 complex, plays an important role in the cellular response to DNA damage but its overexpression contributes to transformation and has been found to correlate with metastasis. However, whether NBS1 participates in IR-induced metastasis needs to be further determined. The aim of this study is to investigate whether radiation-induced HIF-1α stabilization is regulated by NBS1 and thereby promotes tumor cell migration/invasion. Here, we show that both NBS1 and HIF-1α expression are up-regulated after exposure to IR, and NBS1 increases HIF-1α expression at the protein level. In addition, IR treatment promotes the epithelial-mesenchymal transition (EMT) and in vitro cell migration and invasion activity, which could be abolished by suppression of NBS1. Furthermore, NBS1 directly interacts with HIF-1α and reduces the ubiquitination of HIF-1α⋅ Co-expression of HIF-1α and NBS1 in primary tumors of patients with lung adenocarcinoma correlates with a worse prognosis. These results provide a new function of NBS1 in stabilizing HIF-1α under IR, which leads to enhanced cancer cell migration and invasion.


Assuntos
Proteínas de Ciclo Celular/fisiologia , Movimento Celular/efeitos da radiação , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Proteínas Nucleares/fisiologia , Adenocarcinoma/metabolismo , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Transição Epitelial-Mesenquimal , Expressão Gênica , Células HEK293 , Meia-Vida , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Células MCF-7 , Invasividade Neoplásica , Prognóstico , Estabilidade Proteica , Ubiquitinação
19.
Antioxid Redox Signal ; 22(7): 587-602, 2015 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-25328978

RESUMO

AIMS: Mitochondrial succinate dehydrogenase (SDH) is an essential complex of the electron transport chain and tricarboxylic acid cycle. Mutations in the human SDH subunit D frequently lead to paraganglioma (PGL), but the mechanistic consequences of the majority of SDHD polymorphisms have yet to be unraveled. In addition to the originally discovered yeast SDHD subunit Sdh4, a conserved homolog, Shh4, has recently been identified in budding yeast. To assess the pathogenic significance of SDHD mutations in PGL patients, we performed functional studies in yeast. RESULTS: SDHD protein expression was reduced in SDHD-related carotid body tumor tissues. A BLAST search of SDHD to the yeast protein database revealed a novel protein, Shh4, that may have a function similar to human SDHD and yeast Sdh4. The missense SDHD mutations identified in PGL patients were created in Sdh4 and Shh4, and, surprisingly, a severe respiratory incompetence and reduced expression of the mutant protein was observed in the sdh4Δ strain expressing shh4. Although shh4Δ cells showed no respiratory-deficient phenotypes, deletion of SHH4 in sdh4Δ cells further abolished mitochondrial function. Remarkably, sdh4Δ shh4Δ strains exhibited increased reactive oxygen species (ROS) production, nuclear DNA instability, mtDNA mutability, and decreased chronological lifespan. INNOVATION AND CONCLUSION: SDHD mutations are associated with protein and nuclear and mitochondrial genomic instability and increase ROS production in our yeast model. These findings reinforce our understanding of the mechanisms underlying PGL tumorigenesis and point to the yeast Shh4 as a good model to investigate the possible pathogenic relevance of SDHD in PGL polymorphisms.


Assuntos
Neoplasias de Cabeça e Pescoço/metabolismo , Mutação , Paraganglioma/metabolismo , Polimorfismo Genético , Espécies Reativas de Oxigênio/metabolismo , Succinato Desidrogenase/genética , Succinato Desidrogenase/metabolismo , Sequência de Aminoácidos , Carcinogênese/metabolismo , Linhagem Celular , Núcleo Celular/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Neoplasias de Cabeça e Pescoço/genética , Humanos , Mitocôndrias/genética , Dados de Sequência Molecular , Proteínas Mutantes Quiméricas/genética , Paraganglioma/genética , Saccharomyces cerevisiae , Succinato Desidrogenase/química
20.
Cell Mol Life Sci ; 72(9): 1825-37, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25430478

RESUMO

Telomere maintenance is required for chromosome stability, and telomeres are typically elongated by telomerase following DNA replication. In both tumor and yeast cells that lack telomerase, telomeres are maintained via an alternative recombination mechanism. Previous studies have indicated that yeast Sgs1 and Top3 may work together to remove highly negative supercoils that are generated from recombination. However, the mechanism by which cells eradicate highly positive supercoils during recombination remains unclear. In the present study, we demonstrate that TOP2 is involved in telomere-telomere recombination. Disturbance of telomeric structure by RIF1 or RIF2 deletion alleviates the requirement for TOP2 in telomere-telomere recombination. In human telomerase-negative alternative lengthening of telomere (ALT) cells, TOP2α or TOP2ß knockdown decreases ALT-associated PML bodies, increases telomere dysfunction-induced foci and triggers telomere shortening. Similar results were observed when ALT cells were treated with ICRF-193, a TOP2 inhibitor. Importantly, ICRF-193 treatment blocks ALT-associated phenotypes in vitro, causes telomere shortening, and inhibits ALT cell proliferation in mice. Taken together, these findings imply that TOP2 is involved in the ALT pathway, perhaps by resolving the highly positive supercoil structure at the front of the helicase. Inhibition of topoisomerase II may be a promising therapeutic approach that can be used to prevent cell proliferation in ALT-type cancer cells.


Assuntos
DNA Topoisomerases Tipo II/metabolismo , Neoplasias/tratamento farmacológico , Piperazinas/uso terapêutico , Telomerase/genética , Inibidores da Topoisomerase II/uso terapêutico , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , DNA Topoisomerases Tipo II/genética , Dicetopiperazinas , Deleção de Genes , Técnicas de Silenciamento de Genes , Humanos , Camundongos , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Piperazinas/farmacologia , Homeostase do Telômero/efeitos dos fármacos , Proteínas de Ligação a Telômeros/genética , Proteínas de Ligação a Telômeros/metabolismo , Inibidores da Topoisomerase II/farmacologia
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