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1.
PLoS One ; 15(7): e0236291, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32701997

RESUMO

Nuclear IGF1R has been linked to poor outcome in cancer. We recently showed that nuclear IGF1R phosphorylates PCNA and increases DNA damage tolerance. In this paper we aimed to describe this mechanism in cancer tissue as well as in cancer cell lines. In situ proximity ligation assay identified frequent IGF1R and PCNA colocalization in many cancer types. IGF1R/PCNA colocalization was more frequently increased in tumor cells than in adjacent normal, and more prominent in areas with dysplasia and invasion. However, the interaction was often lost in tumors with poor response to neoadjuvant treatment and most metastatic lesions. In two independent cohorts of serous ovarian carcinomas and oropharyngeal squamous cell carcinomas, stronger IGF1R/PCNA colocalization was significantly associated with a higher overall survival. Ex vivo irradiation of ovarian cancer tissue acutely induced IGF1R/PCNA colocalization together with γH2AX-foci formations. In vitro, RAD18 mediated mono-ubiquitination of PCNA during replication stress was dependent on IGF1R kinase activity. DNA fiber analysis revealed that IGF1R activation could rescue stalled DNA replication forks, but only in cancer cells with baseline IGF1R/PCNA interaction. We believe that the IGF1R/PCNA interaction is a basic cellular mechanism to increase DNA stress tolerance during proliferation, but that this mechanism is lost with tumor progression in conjunction with accumulated DNA damage and aberrant strategies to tolerate genomic instability. To exploit this mechanism in IGF1R targeted therapy, IGF1R inhibitors should be explored in the context of concomitant induction of DNA replication stress as well as in earlier clinical stages than previously tried.


Assuntos
Núcleo Celular/metabolismo , Dano ao DNA , Replicação do DNA , Neoplasias/metabolismo , Antígeno Nuclear de Célula em Proliferação/metabolismo , Receptor IGF Tipo 1/metabolismo , Linhagem Celular Tumoral , Humanos , Gradação de Tumores , Neoplasias/patologia , Neoplasias/terapia , Ligação Proteica , Análise de Sobrevida
2.
Nat Commun ; 11(1): 3664, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32694532

RESUMO

Ethanol is a ubiquitous environmental stressor that is toxic to all lifeforms. Here, we use the model eukaryote Saccharomyces cerevisiae to show that exposure to sublethal ethanol concentrations causes DNA replication stress and an increased mutation rate. Specifically, we find that ethanol slows down replication and affects localization of Mrc1, a conserved protein that helps stabilize the replisome. In addition, ethanol exposure also results in the recruitment of error-prone DNA polymerases to the replication fork. Interestingly, preventing this recruitment through mutagenesis of the PCNA/Pol30 polymerase clamp or deleting specific error-prone polymerases abolishes the mutagenic effect of ethanol. Taken together, this suggests that the mutagenic effect depends on a complex mechanism, where dysfunctional replication forks lead to recruitment of error-prone polymerases. Apart from providing a general mechanistic framework for the mutagenic effect of ethanol, our findings may also provide a route to better understand and prevent ethanol-associated carcinogenesis in higher eukaryotes.


Assuntos
Replicação do DNA/efeitos dos fármacos , DNA Polimerase Dirigida por DNA/metabolismo , Etanol/toxicidade , Taxa de Mutação , Saccharomyces cerevisiae/genética , Sistemas CRISPR-Cas/genética , Proteínas de Ciclo Celular/metabolismo , DNA Fúngico/genética , Mutagênese , Testes de Mutagenicidade , Antígeno Nuclear de Célula em Proliferação/genética , Antígeno Nuclear de Célula em Proliferação/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
3.
Nucleic Acids Res ; 48(13): 7218-7238, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32542338

RESUMO

R-loops are formed when replicative forks collide with the transcriptional machinery and can cause genomic instability. However, it is unclear how R-loops are regulated at transcription-replication conflict (TRC) sites and how replisome proteins are regulated to prevent R-loop formation or mediate R-loop tolerance. Here, we report that ATAD5, a PCNA unloader, plays dual functions to reduce R-loops both under normal and replication stress conditions. ATAD5 interacts with RNA helicases such as DDX1, DDX5, DDX21 and DHX9 and increases the abundance of these helicases at replication forks to facilitate R-loop resolution. Depletion of ATAD5 or ATAD5-interacting RNA helicases consistently increases R-loops during the S phase and reduces the replication rate, both of which are enhanced by replication stress. In addition to R-loop resolution, ATAD5 prevents the generation of new R-loops behind the replication forks by unloading PCNA which, otherwise, accumulates and persists on DNA, causing a collision with the transcription machinery. Depletion of ATAD5 reduces transcription rates due to PCNA accumulation. Consistent with the role of ATAD5 and RNA helicases in maintaining genomic integrity by regulating R-loops, the corresponding genes were mutated or downregulated in several human tumors.


Assuntos
ATPases Associadas a Diversas Atividades Celulares/metabolismo , Proteínas de Ligação a DNA/metabolismo , Estruturas R-Loop , RNA Helicases DEAD-box/metabolismo , Células HEK293 , Células HeLa , Humanos , Antígeno Nuclear de Célula em Proliferação/metabolismo
4.
Nat Commun ; 11(1): 2147, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358495

RESUMO

Upon genotoxic stress, PCNA ubiquitination allows for replication of damaged DNA by recruiting lesion-bypass DNA polymerases. However, PCNA is also ubiquitinated during normal S-phase progression. By employing 293T and RPE1 cells deficient in PCNA ubiquitination, generated through CRISPR/Cas9 gene editing, here, we show that this modification promotes cellular proliferation and suppression of genomic instability under normal growth conditions. Loss of PCNA-ubiquitination results in DNA2-dependent but MRE11-independent nucleolytic degradation of nascent DNA at stalled replication forks. This degradation is linked to defective gap-filling in the wake of the replication fork and incomplete Okazaki fragment maturation, which interferes with efficient PCNA unloading by ATAD5 and subsequent nucleosome deposition by CAF-1. Moreover, concomitant loss of PCNA-ubiquitination and the BRCA pathway results in increased nascent DNA degradation and PARP inhibitor sensitivity. In conclusion, we show that by ensuring efficient Okazaki fragment maturation, PCNA-ubiquitination protects fork integrity and promotes the resistance of BRCA-deficient cells to PARP-inhibitors.


Assuntos
Antígeno Nuclear de Célula em Proliferação/metabolismo , Linhagem Celular Tumoral , Montagem e Desmontagem da Cromatina/genética , Montagem e Desmontagem da Cromatina/fisiologia , Ensaio Cometa , DNA/genética , Dano ao DNA/genética , Dano ao DNA/fisiologia , Reparo do DNA/genética , Reparo do DNA/fisiologia , Replicação do DNA/genética , Replicação do DNA/fisiologia , Imunofluorescência , Instabilidade Genômica/genética , Instabilidade Genômica/fisiologia , Células HEK293 , Células HeLa , Humanos , Antígeno Nuclear de Célula em Proliferação/genética , Ligação Proteica , Ubiquitinação/genética , Ubiquitinação/fisiologia
5.
PLoS Pathog ; 16(5): e1008190, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32413071

RESUMO

DNA replication protein Cdc45 is an integral part of the eukaryotic replicative helicase whose other components are the Mcm2-7 core, and GINS. We identified a PIP box motif in Leishmania donovani Cdc45. This motif is typically linked to interaction with the eukaryotic clamp proliferating cell nuclear antigen (PCNA). The homotrimeric PCNA can potentially bind upto three different proteins simultaneously via a loop region present in each monomer. Multiple binding partners have been identified from among the replication machinery in other eukaryotes, and the concerted /sequential binding of these partners are central to the fidelity of the replication process. Though conserved in Cdc45 across Leishmania species and Trypanosoma cruzi, the PIP box is absent in Trypanosoma brucei Cdc45. Here we investigate the possibility of Cdc45-PCNA interaction and the role of such an interaction in the in vivo context. Having confirmed the importance of Cdc45 in Leishmania DNA replication we establish that Cdc45 and PCNA interact stably in whole cell extracts, also interacting with each other directly in vitro. The interaction is mediated via the Cdc45 PIP box. This PIP box is essential for Leishmania survival. The importance of the Cdc45 PIP box is also examined in Schizosaccharomyces pombe, and it is found to be essential for cell survival here as well. Our results implicate a role for the Leishmania Cdc45 PIP box in recruiting or stabilizing PCNA on chromatin. The Cdc45-PCNA interaction might help tether PCNA and associated replicative DNA polymerase to the DNA template, thus facilitating replication fork elongation. Though multiple replication proteins that associate with PCNA have been identified in other eukaryotes, this is the first report demonstrating a direct interaction between Cdc45 and PCNA, and while our analysis suggests the interaction may not occur in human cells, it indicates that it may not be confined to trypanosomatids.


Assuntos
Leishmania donovani/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/fisiologia , Cromatina/genética , DNA Helicases/metabolismo , Replicação do DNA/fisiologia , Leishmania donovani/genética , Proteínas Nucleares/genética , Proteínas Nucleares/fisiologia , Nucleotidiltransferases/genética , Antígeno Nuclear de Célula em Proliferação/genética , Antígeno Nuclear de Célula em Proliferação/metabolismo , Ligação Proteica , Domínios Proteicos , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/fisiologia , Análise de Sequência de Proteína/métodos
6.
Adv Exp Med Biol ; 1241: 35-45, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32383114

RESUMO

Polymerase δ-interacting protein 2 (PolDIP2) is involved in the multiple protein-protein interactions and plays roles in many cellular processes including regulation of the nuclear redox environment, organization of the mitotic spindle and chromosome segregation, pre-mRNA processing, mitochondrial morphology and functions, cell migration and cellular adhesion. PolDIP2 is also a binding partner of high-fidelity DNA polymerase delta, PCNA and a number of translesion and repair DNA polymerases. The growing evidence suggests that PolDIP2 is a general regulatory protein in DNA damage response. However PolDIP2 functions in DNA translesion synthesis and repair are not fully understood. In this review, we address the functional interaction of PolDIP2 with human DNA polymerases and discuss the possible functions in DNA damage response.


Assuntos
Dano ao DNA , Replicação do DNA , DNA Polimerase Dirigida por DNA/metabolismo , DNA/biossíntese , Proteínas Nucleares/metabolismo , Humanos , Antígeno Nuclear de Célula em Proliferação/metabolismo
7.
Arch Biochem Biophys ; 688: 108404, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32416101

RESUMO

Hemangioma (HA) is the most common benign tumor and formed by the proliferating endothelial cells of blood vessels. Interleukins (ILs) have been reported to be critical for HA progression. Our present study found that the expression of IL-10 was decreased in HA cells and tissues as compared to their corresponding controls. Treatment with recombinant IL-10 (rIL-10) can suppress the proliferation of HA cells via suppression of proliferating cell nuclear antigen (PCNA), while over expression of PCNA can attenuate rIL-10-inhibited cell proliferation. Further, rIL-10 can decrease the promoter activity and mRNA stability of PCNA in HA cells. Mechanistically, rIL-10 can increase expression of miR-27b-3p to decrease mRNA stability of PCNA, while down regulation of YY1 is involved in rIL-10 suppressed transcription of PCNA. Collectively, IL-10 can suppress the expression of PCNA via miR-27b-3p mediated suppression of mRNA stability and YY1 mediated down regulation of transcription. It suggested that rIL-10 might be a potential therapeutic approach for HA development and progression.


Assuntos
Células Endoteliais/metabolismo , Hemangioma/prevenção & controle , Interleucina-10/farmacologia , Antígeno Nuclear de Célula em Proliferação/metabolismo , Proliferação de Células/fisiologia , Progressão da Doença , Hemangioma/metabolismo , Células Endoteliais da Veia Umbilical Humana , Humanos , Interleucina-10/metabolismo , MicroRNAs/metabolismo , Antígeno Nuclear de Célula em Proliferação/genética , Estabilidade de RNA/efeitos dos fármacos , RNA Mensageiro/metabolismo , Fator de Transcrição YY1/metabolismo
8.
Tumour Biol ; 42(4): 1010428320914475, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32252611

RESUMO

Hepatocellular carcinoma is a major cause of cancer mortality worldwide. The outcome of hepatocellular carcinoma depends mainly on its early diagnosis. To date, the performance of traditional biomarkers is unsatisfactory. Polo-like kinase 1 is a serine/threonine kinase that plays essential roles in cell cycle progression and deoxyribonucleic acid damage. Moreover, polo-like kinase 1 knockdown decreases the survival of hepatocellular carcinoma cells; therefore, polo-like kinase 1 is an attractive target for anticancer treatments. Nobiletin, a natural polymethoxy flavonoid, exhibits a potential antiproliferative effect against a wide variety of cancers. This study targets to identify a reliable diagnostic biomarker for hepatocellular carcinoma and provide a potential therapeutic target for its treatment. Polo-like kinase 1 levels were analyzed in 44 hepatocellular carcinoma patients, 33 non-hepatocellular carcinoma liver cirrhosis patients and 15 healthy controls using the enzyme-linked immunosorbent assay method. Receiver operating characteristics curve analysis was used to establish a predictive model for polo-like kinase 1 relative to α-fetoprotein in hepatocellular carcinoma diagnosis. Furthermore, in the in vitro study, gene expressions were assessed by quantitative polymerase chain reaction in two human hepatocellular carcinoma cell lines after treatment with doxorubicin and polo-like kinase 1 inhibitor volasertib (Vola) either alone or in combination with nobiletin. Cell viability was also determined using the crystal violet assay.: Serum polo-like kinase 1 levels in hepatocellular carcinoma patients were significantly higher than liver cirrhosis and control groups (p < 0.0001). Polo-like kinase 1 showed a reasonable sensitivity, specificity, positive predictive value, and negative predictive value in hepatocellular carcinoma diagnosis. Moreover, nobiletin improved inhibition of cell growth induced by Vola and doxorubicin. Regarding reverse transcription polymerase chain reaction results, nobiletin suppressed expressions of polo-like kinase 1 and proliferating cell nuclear antigen and elevated expressions of P53, poly (ADPribose) polymerase 1, and caspase-3. Nobiletin/doxorubicin and nobiletin/Vola showed a significant increase in caspase-3 activity indicating cell apoptosis. Polo-like kinase 1 may be a potential biomarker for hepatocellular carcinoma diagnosis and follow-up during treatment with chemotherapies. In addition, nobiletin synergistically potentiates the doxorubicin and Vola-mediated anticancer effect that may be attributed partly to suppression of polo-like kinase 1 and proliferating cell nuclear antigen expression and enhancement of chemotherapy-induced apoptosis.


Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma Hepatocelular/patologia , Proteínas de Ciclo Celular/metabolismo , Neoplasias Hepáticas/patologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Apoptose/efeitos dos fármacos , Biomarcadores Tumorais/genética , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Caspase 3/metabolismo , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Doxorrubicina/farmacologia , Flavonas/farmacologia , Células Hep G2 , Humanos , Cirrose Hepática/patologia , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Antígeno Nuclear de Célula em Proliferação/metabolismo , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/genética , Pteridinas/farmacologia
9.
Nucleic Acids Res ; 48(10): 5540-5554, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32347931

RESUMO

In the fight against antimicrobial resistance, the bacterial DNA sliding clamp, ß-clamp, is a promising drug target for inhibition of DNA replication and translesion synthesis. The ß-clamp and its eukaryotic homolog, PCNA, share a C-terminal hydrophobic pocket where all the DNA polymerases bind. Here we report that cell penetrating peptides containing the PCNA-interacting motif APIM (APIM-peptides) inhibit bacterial growth at low concentrations in vitro, and in vivo in a bacterial skin infection model in mice. Surface plasmon resonance analysis and computer modeling suggest that APIM bind to the hydrophobic pocket on the ß-clamp, and accordingly, we find that APIM-peptides inhibit bacterial DNA replication. Interestingly, at sub-lethal concentrations, APIM-peptides have anti-mutagenic activities, and this activity is increased after SOS induction. Our results show that although the sequence homology between the ß-clamp and PCNA are modest, the presence of similar polymerase binding pockets in the DNA clamps allows for binding of the eukaryotic binding motif APIM to the bacterial ß-clamp. Importantly, because APIM-peptides display both anti-mutagenic and growth inhibitory properties, they may have clinical potential both in combination with other antibiotics and as single agents.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , DNA Polimerase III/antagonistas & inibidores , Peptídeos/química , Peptídeos/farmacologia , Animais , Antibacterianos/metabolismo , Antibacterianos/uso terapêutico , DNA Polimerase III/química , Replicação do DNA/efeitos dos fármacos , DNA Polimerase Dirigida por DNA , Feminino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Camundongos Endogâmicos BALB C , Mutagênese/efeitos dos fármacos , Inibidores da Síntese de Ácido Nucleico/química , Inibidores da Síntese de Ácido Nucleico/farmacologia , Inibidores da Síntese de Ácido Nucleico/uso terapêutico , Peptídeos/metabolismo , Peptídeos/uso terapêutico , Antígeno Nuclear de Célula em Proliferação/metabolismo , Domínios e Motivos de Interação entre Proteínas , Infecções Cutâneas Estafilocócicas/tratamento farmacológico , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/genética , Staphylococcus epidermidis/crescimento & desenvolvimento
10.
Vascular ; 28(4): 396-404, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32228224

RESUMO

BACKGROUND AND OBJECTIVES: Wall shear stress plays a critical role in neointimal hyperplasia after stent implantation. It has been found that there is an inverse relation between wall shear stress and neointimal hyperplasia. This study hypothesized that the increase of arterial wall shear stress caused by arteriovenous fistula could reduce neointimal hyperplasia after stents implantation. METHODS AND RESULTS: Thirty-six male rabbits were randomly divided into three groups: STENT, rabbits received stent implantation into right common carotid artery; STENT/arteriovenous fistula, rabbits received stent implantation into right common carotid artery and carotid-jugular arteriovenous fistula; Control, rabbits received no treatment. After 21 days, stented common carotid artery specimens were harvested for histological staining and protein expression analysis. In STENT group, wall shear stress maintained at a low level from 43.2 to 48.9% of baseline. In STENT/arteriovenous fistula group, wall shear stress gradually increased to 86% over baseline. There was a more significant neointimal hyperplasia in group STENT compared with the STENT/arteriovenous fistula group (neointima area: 0.87 mm2 versus 0.19 mm2; neointima-to-media area ratio: 1.13 versus 0.18). Western blot analysis demonstrated that the protein level of endothelial nitric oxide synthase in STENT group was significantly lower than that in STENT/arteriovenous fistula group, but the protein levels of proliferating cell nuclear antigen, vascular cell adhesion molecule 1, phospho-p38 mitogen-activated protein kinase (Pp38), and phospho-c-Jun N-terminal kinase in STENT group were significantly higher than that in the STENT group. CONCLUSION: High wall shear stress caused by arteriovenous fistula as associated with the induction in neointimal hyperplasia after stent implantation. The underlying mechanisms may be related to modulating the expression and activation of endothelial nitric oxide synthase, vascular cell adhesion molecule 1, p38, and c-Jun N-terminal kinase.


Assuntos
Derivação Arteriovenosa Cirúrgica , Artéria Carótida Primitiva/cirurgia , Procedimentos Endovasculares/instrumentação , Veias Jugulares/cirurgia , Neointima , Animais , Artéria Carótida Primitiva/metabolismo , Artéria Carótida Primitiva/patologia , Artéria Carótida Primitiva/fisiopatologia , Procedimentos Endovasculares/efeitos adversos , Hiperplasia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Veias Jugulares/fisiopatologia , Masculino , Modelos Animais , Óxido Nítrico Sintase Tipo III/metabolismo , Fosforilação , Antígeno Nuclear de Célula em Proliferação/metabolismo , Coelhos , Fluxo Sanguíneo Regional , Stents , Estresse Mecânico , Molécula 1 de Adesão de Célula Vascular/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
11.
Mol Cell ; 78(4): 725-738.e4, 2020 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-32277910

RESUMO

Concomitant with DNA replication, the chromosomal cohesin complex establishes cohesion between newly replicated sister chromatids. Several replication-fork-associated "cohesion establishment factors," including the multifunctional Ctf18-RFC complex, aid this process in as yet unknown ways. Here, we show that Ctf18-RFC's role in sister chromatid cohesion correlates with PCNA loading but is separable from its role in the replication checkpoint. Ctf18-RFC loads PCNA with a slight preference for the leading strand, which is dispensable for DNA replication. Conversely, the canonical Rfc1-RFC complex preferentially loads PCNA onto the lagging strand, which is crucial for DNA replication but dispensable for sister chromatid cohesion. The downstream effector of Ctf18-RFC is cohesin acetylation, which we place toward a late step during replication maturation. Our results suggest that Ctf18-RFC enriches and balances PCNA levels at the replication fork, beyond the needs of DNA replication, to promote establishment of sister chromatid cohesion and possibly other post-replicative processes.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Cromátides/fisiologia , Proteínas Cromossômicas não Histona/metabolismo , Cromossomos Fúngicos/fisiologia , Replicação do DNA , Antígeno Nuclear de Célula em Proliferação/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Acetiltransferases/genética , Acetiltransferases/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Segregação de Cromossomos , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Antígeno Nuclear de Célula em Proliferação/genética , Proteína de Replicação C/genética , Proteína de Replicação C/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética
12.
Medicine (Baltimore) ; 99(16): e19755, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32311975

RESUMO

Although proliferating cell nuclear antigen (PCNA) plays an important role in tumor proliferation and its expression level is closely related to the biological activity of tumor cells, PCNA expression in non-small cell lung cancer (NSCLC) has been seldom reported. In this study, we aimed to investigate the significance of PCNA expression in NSCLC tissues. PCNA expression in NSCLC and adjacent tissues were assessed by immunohistochemistry (IHC), western blotting, and reverse transcription polymerase chain reaction. Single factor analysis was used to study the relationship between the expression of PCNA and clinicopathological features of NSCLC. Multi-factor Cox survival analysis was used to evaluate the relationship between the expression of PCNA and overall survival of postoperative NSCLC patients. The areas under the receiver operating characteristics were calculated to evaluate the value of PCNA expression level in predicting the 3-year survival of NSCLC patients. IHC analysis showed that the positive expression rates of PCNA protein in NSCLC and adjacent tissues were 91.79% (257/280) and 25.83% (31/120), respectively. Western blotting confirmed that PCNA protein level was significantly higher in NSCLC tissues than in the adjacent tissues (P < .05). Reverse transcription polymerase chain reaction showed that the positive rate of PCNA mRNA in NSCLC was 88.93% (249/280), which was significantly higher than that in adjacent tissues 29.17% (35/120) (P < .05). Both PCNA mRNA and protein levels were correlated with tumor differentiation, size, metastasis, and stage in NSCLC. Patients exhibiting higher PCNA protein expression had a significantly shorter disease-specific survival rate than the other patients. PCNA protein level and tumor pathological type, metastasis, differentiation degree, and stage were independent factors affecting the overall survival of postoperative patients. The areas under the receiver operating characteristics of PCNA mRNA for predicting the 3-year survival of NSCLC patients was 0.89 (0.79-0.98), with a sensitivity and specificity of 0.84 and 0.76, respectively. In conclusion, high PCNA protein and mRNA levels may be associated with the occurrence, development, and prognosis of NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/metabolismo , Neoplasias Pulmonares/metabolismo , Antígeno Nuclear de Célula em Proliferação/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/metabolismo , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Carcinoma Pulmonar de Células não Pequenas/cirurgia , China/epidemiologia , Estudos Transversais , Feminino , Humanos , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/cirurgia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
13.
Cardiovasc Ther ; 2020: 1926249, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32328171

RESUMO

Isoliquiritigenin (ISL) is a flavonoid isolated mainly from the licorice plant, a traditional Chinese herb. ISL has shown anticancer, anti-inflammatory, antioxidant, and antidiabetic activities. However, the pharmaceutical effects of ISL on atherosclerosis are seldom explored. In this study, we used apolipoprotein E (ApoE) knockout mouse model and angiotensin II- (Ang II-) stimulated vascular smooth muscle cells (VSMCs) to elucidate the pharmacological mechanism of ISL to inhibit atherosclerosis. We found that in ApoE-/- mice ISL could attenuate atherosclerotic lesion, reduce serum lipid levels, and inhibit TRPC5 expression. In vitro, ISL inhibited Ang II-stimulated proliferation of VSMCs and suppressed Ang II-induced TRPC5 and PCNA expressions in a dose-dependent fashion. In conclusion, our findings provide novel insight into the pharmacological effects of ISL on atherosclerosis and suggest that ISL is beneficial for cardiovascular protection.


Assuntos
Aorta/efeitos dos fármacos , Doenças da Aorta/prevenção & controle , Aterosclerose/prevenção & controle , Chalconas/farmacologia , Placa Aterosclerótica , Canais de Cátion TRPC/antagonistas & inibidores , Animais , Aorta/metabolismo , Aorta/patologia , Doenças da Aorta/genética , Doenças da Aorta/metabolismo , Doenças da Aorta/patologia , Aterosclerose/genética , Aterosclerose/metabolismo , Aterosclerose/patologia , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Modelos Animais de Doenças , Lipídeos/sangue , Camundongos Endogâmicos C57BL , Camundongos Knockout para ApoE , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Antígeno Nuclear de Célula em Proliferação/genética , Antígeno Nuclear de Célula em Proliferação/metabolismo , Transdução de Sinais , Canais de Cátion TRPC/metabolismo
14.
Nat Struct Mol Biol ; 27(5): 461-471, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32341532

RESUMO

The coordination of DNA unwinding and synthesis at replication forks promotes efficient and faithful replication of chromosomal DNA. Disruption of the balance between helicase and polymerase activities during replication stress leads to fork progression defects and activation of the Rad53 checkpoint kinase, which is essential for the functional maintenance of stalled replication forks. The mechanism of Rad53-dependent fork stabilization is not known. Using reconstituted budding yeast replisomes, we show that mutational inactivation of the leading strand DNA polymerase, Pol ε, dNTP depletion, and chemical inhibition of DNA polymerases cause excessive DNA unwinding by the replicative DNA helicase, CMG, demonstrating that budding yeast replisomes lack intrinsic mechanisms that control helicase-polymerase coupling at the fork. Importantly, we find that the Rad53 kinase restricts excessive DNA unwinding at replication forks by limiting CMG helicase activity, suggesting a mechanism for fork stabilization by the replication checkpoint.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Quinase do Ponto de Checagem 2/metabolismo , DNA Helicases/metabolismo , Replicação do DNA , DNA Fúngico/biossíntese , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Ciclo Celular/genética , Quinase do Ponto de Checagem 2/genética , DNA Helicases/genética , DNA Polimerase II/genética , DNA Polimerase II/metabolismo , DNA Polimerase III/genética , DNA Polimerase III/metabolismo , Primers do DNA , DNA Fúngico/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Mutação , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Nucleossomos/genética , Plasmídeos , Antígeno Nuclear de Célula em Proliferação/genética , Antígeno Nuclear de Célula em Proliferação/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
15.
Nat Struct Mol Biol ; 27(5): 450-460, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32341533

RESUMO

Leading-strand template aberrations cause helicase-polymerase uncoupling and impede replication fork progression, but the details of how uncoupled forks are restarted remain uncertain. Using purified proteins from Saccharomyces cerevisiae, we have reconstituted translesion synthesis (TLS)-mediated restart of a eukaryotic replisome following collision with a cyclobutane pyrimidine dimer. We find that TLS functions 'on the fly' to promote resumption of rapid replication fork rates, despite lesion bypass occurring uncoupled from the Cdc45-MCM-GINS (CMG) helicase. Surprisingly, the main lagging-strand polymerase, Pol δ, binds the leading strand upon uncoupling and inhibits TLS. Pol δ is also crucial for efficient recoupling of leading-strand synthesis to CMG following lesion bypass. Proliferating cell nuclear antigen monoubiquitination positively regulates TLS to overcome Pol δ inhibition. We reveal that these mechanisms of negative and positive regulation also operate on the lagging strand. Our observations have implications for both fork restart and the division of labor during leading-strand synthesis generally.


Assuntos
Replicação do DNA , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Acetiltransferases/genética , Acetiltransferases/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , DNA Polimerase II/genética , DNA Polimerase II/metabolismo , DNA Polimerase III/genética , DNA Polimerase III/metabolismo , Reparo do DNA , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas de Manutenção de Minicromossomo/genética , Proteínas de Manutenção de Minicromossomo/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Antígeno Nuclear de Célula em Proliferação/genética , Antígeno Nuclear de Célula em Proliferação/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Enzimas Ativadoras de Ubiquitina/genética , Enzimas Ativadoras de Ubiquitina/metabolismo , Ubiquitinação
16.
Environ Toxicol ; 35(9): 971-981, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32302048

RESUMO

Hepatocellular carcinoma (HCC) ranks the sixth position among various cancers worldwide. Recent research shows that natural and dietary compounds possess many therapeutic effects. Citral is a monoterpene aldehyde that contains geranial and neral. The present study was considered to study the role of citral against N-nitrosodiethylamine (NDEA)-induced HCC via modulation of antioxidants and xenobiotic-metabolizing enzymes in vivo. NDEA-alone-administered group II animals profoundly showed increased tumor incidence, reactive oxygen species, liver marker enzyme levels, serum bilirubin levels, tumor markers of carcinoembryonic antigen, α-fetoprotein, proliferative markers of argyrophilic nucleolar organizing regions, proliferating cell nuclear antigen (PCNA) expressions, phase I xenobiotic-metabolic enzymes and simultaneously decreased antioxidants, and phase II enzymes levels. Citral (100 mg/kg b.w.) treatment significantly reverted the levels in group III cancer-bearing animals when compared to group II cancer-bearing animals. In group IV animals, citral-alone administration did not produce any adverse effect during the experimental condition. Based on the results, citral significantly inhibits the hepatocellular carcinogenesis through restoring the antioxidants and phase II xenobiotic-enzyme levels; thereby, it strongly proves as an antiproliferative agent against rat HCC.


Assuntos
Monoterpenos Acíclicos/uso terapêutico , Antineoplásicos Fitogênicos/uso terapêutico , Antioxidantes/metabolismo , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Animais , Antígeno Carcinoembrionário/análise , Carcinoma Hepatocelular/enzimologia , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Dietilnitrosamina , Humanos , Testes de Função Hepática , Neoplasias Hepáticas Experimentais/enzimologia , Neoplasias Hepáticas Experimentais/patologia , Masculino , Antígeno Nuclear de Célula em Proliferação/metabolismo , Ratos , Ratos Wistar , alfa-Fetoproteínas/análise
17.
Life Sci ; 250: 117561, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32198052

RESUMO

AIMS: Pyruvate kinase M2 (PKM2), a unique isoform of the pyruvate kinases, not only acts as a crucial metabolic enzyme when it locates in the cytoplasm, but also plays important roles in tumor formation and growth when it accumulates in the nuclei. Our aim was to investigate the potential role of PKM2 in liver regeneration in mice insulted with carbon tetrachloride (CCl4). MATERIAL AND METHODS: The liver regeneration model was established by intraperitoneal injection of CCl4 for 48 h in male BALB/c mice. The expression of PKM2, phospho-STAT3, STAT3, proliferating cell nuclear antigen (PCNA) and Cyclin D1 were evaluated by western blot. The distribution of PKM2 was verified by immunofluorescence staining. The degree of injured region was assessed by hematoxylin and eosin (HE) staining. The proliferation of liver cells was tested by Immunohistochemistry. KEY FINDINGS: The nuclear accumulation of PKM2 increased in the liver treated with CCl4, but treatment with ML-265 significantly suppressed CCl4-induced nuclear accumulation of PKM2. In addition, treatment with ML-265 suppressed the level of cyclin D1 and proliferating cell nuclear antigen (PCNA), reduced the count of Ki67-positive hepatocytes, and expanded the damaged region in histological examination. Meanwhile, treatment with ML-265 suppressed the phosphorylation of nuclear signal transducer and activator of transcription 3 (STAT3). Inhibition of STAT3 by stattic made the same effects as ML-265. SIGNIFICANCE: These data uncovered the role of nuclear PKM2 in liver regeneration and the pro-proliferation effects of nuclear PKM2 may be through targeting its downstream transcription factor STAT3.


Assuntos
Núcleo Celular/metabolismo , Regeneração Hepática , Piruvato Quinase/metabolismo , Fator de Transcrição STAT3/metabolismo , Animais , Tetracloreto de Carbono , Proliferação de Células , Citoplasma/metabolismo , Hepatócitos/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Fígado/metabolismo , Hepatopatias/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Fosforilação/efeitos dos fármacos , Antígeno Nuclear de Célula em Proliferação/metabolismo
18.
Proc Natl Acad Sci U S A ; 117(11): 5791-5800, 2020 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-32123106

RESUMO

Targeted degradation approaches such as proteolysis targeting chimeras (PROTACs) offer new ways to address disease through tackling challenging targets and with greater potency, efficacy, and specificity over traditional approaches. However, identification of high-affinity ligands to serve as PROTAC starting points remains challenging. As a complementary approach, we describe a class of molecules termed biological PROTACs (bioPROTACs)-engineered intracellular proteins consisting of a target-binding domain directly fused to an E3 ubiquitin ligase. Using GFP-tagged proteins as model substrates, we show that there is considerable flexibility in both the choice of substrate binders (binding positions, scaffold-class) and the E3 ligases. We then identified a highly effective bioPROTAC against an oncology target, proliferating cell nuclear antigen (PCNA) to elicit rapid and robust PCNA degradation and associated effects on DNA synthesis and cell cycle progression. Overall, bioPROTACs are powerful tools for interrogating degradation approaches, target biology, and potentially for making therapeutic impacts.


Assuntos
Antígeno Nuclear de Célula em Proliferação/metabolismo , Engenharia de Proteínas/métodos , Proteólise , Ubiquitina-Proteína Ligases/genética , Sítios de Ligação , Células HEK293 , Humanos , Terapia de Alvo Molecular/métodos , Antígeno Nuclear de Célula em Proliferação/química , Ligação Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Ubiquitina-Proteína Ligases/química , Ubiquitina-Proteína Ligases/metabolismo
19.
Nanotoxicology ; 14(5): 683-695, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32189538

RESUMO

The aim of this survey is to explore the possible effects of unsupported and supported copper nanoparticles (CuNPs) of different morphologies on basic ovarian cell functions. For this purpose, we have compared the activity of unsupported spherical, triangular, and hexagonal CuNPs, as well as of spherical CuNPs supported on titania, zeolite Y and activated charcoal (0, 1, 10, or 100 ng/mL) on cultured porcine ovarian granulosa cells. Cell viability, proliferation (accumulation of proliferating cell nuclear antigen, PCNA), apoptosis (accumulation of Bcl-2-associated X protein, bax) and release of steroid hormones progesterone, testosterone, and 17ß-estradiol have been analyzed by the Trypan blue test, quantitative immunocytochemistry, and ELISA, respectively. Cell viability decreased after treatment with hexagonal CuNPs, whilst all the other CuNPs increased it. Unsupported spherical and hexagonal CuNPs, and spherical CuNPs/titania reduced PCNA accumulation; in contrast, an increase was noted for unsupported triangular CuNPs and CuNPs/zeolite Y. Bax accumulation was not affected by hexagonal CuNPs, whereas CuNPs/zeolite Y promoted it and all the other CuNPs depleted it. The release of all steroid hormones was inhibited by CuNPs/titanium dioxide and stimulated by CuNPs/charcoal, whilst CuNPs/zeolite Y promoted the testosterone and 17ß-estradiol output, but not that of progesterone. These results demonstrate the direct, mainly stimulatory, impact of CuNPs on basic ovarian cell functions. The character of the CuNPs' action depends on their shape and support. Therefore, CuNPs with appropriate chemical modification could be potentially useful for the control of reproductive processes and treatment of reproductive disorders.


Assuntos
Proliferação de Células/efeitos dos fármacos , Cobre/química , Cobre/toxicidade , Hormônios Gonadais/metabolismo , Células da Granulosa/efeitos dos fármacos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/toxicidade , Animais , Apoptose/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Carvão Vegetal/química , Relação Dose-Resposta a Droga , Feminino , Células da Granulosa/metabolismo , Células da Granulosa/fisiologia , Ovário/metabolismo , Ovário/patologia , Antígeno Nuclear de Célula em Proliferação/metabolismo , Propriedades de Superfície , Suínos , Titânio/química , Zeolitas/química
20.
Nat Commun ; 11(1): 1591, 2020 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-32221299

RESUMO

Replicative DNA polymerases (DNAPs) have evolved the ability to copy the genome with high processivity and fidelity. In Eukarya and Archaea, the processivity of replicative DNAPs is greatly enhanced by its binding to the proliferative cell nuclear antigen (PCNA) that encircles the DNA. We determined the cryo-EM structure of the DNA-bound PolD-PCNA complex from Pyrococcus abyssi at 3.77 Å. Using an integrative structural biology approach - combining cryo-EM, X-ray crystallography, protein-protein interaction measurements, and activity assays - we describe the molecular basis for the interaction and cooperativity between a replicative DNAP and PCNA. PolD recruits PCNA via a complex mechanism, which requires two different PIP-boxes. We infer that the second PIP-box, which is shared with the eukaryotic Polα replicative DNAP, plays a dual role in binding either PCNA or primase, and could be a master switch between an initiation and a processive phase during replication.


Assuntos
DNA Polimerase Dirigida por DNA/química , DNA Polimerase Dirigida por DNA/metabolismo , Antígeno Nuclear de Célula em Proliferação/química , Antígeno Nuclear de Célula em Proliferação/metabolismo , Archaea , Proteínas Arqueais/química , Proteínas Arqueais/metabolismo , Clonagem Molecular , Microscopia Crioeletrônica , Cristalografia por Raios X , DNA/metabolismo , Proteínas de Ligação a DNA/química , DNA Polimerase Dirigida por DNA/genética , Eucariotos , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Pyrococcus abyssi/genética , Pyrococcus abyssi/metabolismo , Proteínas Recombinantes de Fusão
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