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1.
Life Sci ; 259: 118168, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32739469

RESUMO

AIMS: Circular RNA PRKCI (circPRKCI) and poly ADP-ribose polymerase 9 (PARP9) are related to the development of cancers. In this study, we aimed to explore the regulatory mechanisms between circPRKCI and PARP9 in EC progression and radioresistance. MATERIALS AND METHODS: The levels of circPRKCI, PARP9 mRNA, and miR-186-5p were assessed by quantitative real time polymerase chain reaction (qRT-PCR). Western blot analysis was employed to examine the levels of several proteins. The viability, colony formation, cell cycle progression, and apoptosis of EC cells were determined with CCK-8, colony formation, or flow cytometry assays. The relationship between circPRKCI or PARP9 and miR-186-5p was verified with the dual-luciferase reporter and RIP assays. KEY FINDINGS: We observed that circPRKCI and PARP9 were upregulated while miR-186-5p was downregulated in EC tissues and cells. Furthermore, circPRKCI knockdown decreased tumor growth in vivo and constrained cell viability, colony formation, cell cycle progression, elevated cell radiosensitivity in EC cells in vitro. Importantly, circPRKCI modulated PARP9 expression through sponging miR-186-5p. Besides, PARP9 overexpression overturned circPRKCI silencing-mediated effects on the viability, colony formation, cell cycle progression, and radiosensitivity of EC cells. SIGNIFICANCE: CircPRKCI regulated cell malignancy and radioresistance through modulating the miR-186-5p /PARP9 axis in EC, which provided a might target for EC treatment.


Assuntos
Neoplasias Esofágicas/genética , Neoplasias Esofágicas/terapia , Isoenzimas/genética , MicroRNAs/genética , Proteínas de Neoplasias/genética , Poli(ADP-Ribose) Polimerases/genética , Proteína Quinase C/genética , RNA Circular/genética , Animais , Apoptose , Ciclo Celular , Linhagem Celular Tumoral , Progressão da Doença , Neoplasias Esofágicas/radioterapia , Regulação Neoplásica da Expressão Gênica/genética , Técnicas de Silenciamento de Genes , Humanos , Camundongos , Células-Tronco Neoplásicas , Interferência de RNA , Radiossensibilizantes/uso terapêutico , Ensaios Antitumorais Modelo de Xenoenxerto
3.
Nucleic Acids Res ; 48(13): 7252-7264, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32542389

RESUMO

The DNA damage response is essential to maintain genomic stability, suppress replication stress, and protect against carcinogenesis. The ATR-CHK1 pathway is an essential component of this response, which regulates cell cycle progression in the face of replication stress. PARP14 is an ADP-ribosyltransferase with multiple roles in transcription, signaling, and DNA repair. To understand the biological functions of PARP14, we catalogued the genetic components that impact cellular viability upon loss of PARP14 by performing an unbiased, comprehensive, genome-wide CRISPR knockout genetic screen in PARP14-deficient cells. We uncovered the ATR-CHK1 pathway as essential for viability of PARP14-deficient cells, and identified regulation of DNA replication dynamics as an important mechanistic contributor to the synthetic lethality observed. Our work shows that PARP14 is an important modulator of the response to ATR-CHK1 pathway inhibitors.


Assuntos
Replicação do DNA , Poli(ADP-Ribose) Polimerases/metabolismo , Mutações Sintéticas Letais , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Sistemas CRISPR-Cas , Linhagem Celular Tumoral , Quinase 1 do Ponto de Checagem/genética , Quinase 1 do Ponto de Checagem/metabolismo , Humanos , Poli(ADP-Ribose) Polimerases/genética
4.
Proc Natl Acad Sci U S A ; 117(24): 13447-13456, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32482854

RESUMO

Precisely controlling the activation of transcription factors is crucial for physiology. After a transcription factor is activated and carries out its transcriptional activity, it also needs to be properly deactivated. Here, we report a deactivation mechanism of HIF-1 and several other oncogenic transcription factors. HIF-1 promotes the transcription of an ADP ribosyltransferase, TiPARP, which serves to deactivate HIF-1. Mechanistically, TiPARP forms distinct nuclear condensates or nuclear bodies in an ADP ribosylation-dependent manner. The TiPARP nuclear bodies recruit both HIF-1α and an E3 ubiquitin ligase HUWE1, which promotes the ubiquitination and degradation of HIF-1α. Similarly, TiPARP promotes the degradation of c-Myc and estrogen receptor. By suppressing HIF-1α and other oncogenic transcription factors, TiPARP exerts strong antitumor effects both in cell culture and in mouse xenograft models. Our work reveals TiPARP as a negative-feedback regulator for multiple oncogenic transcription factors, provides insights into the functions of protein ADP-ribosylation, and suggests activating TiPARP as an anticancer strategy.


Assuntos
Núcleo Celular/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Proteínas Supressoras de Tumor/metabolismo , ADP-Ribosilação , Animais , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Receptor alfa de Estrogênio/metabolismo , Retroalimentação Fisiológica , Regulação Neoplásica da Expressão Gênica , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Camundongos , Poli(ADP-Ribose) Polimerases/química , Poli(ADP-Ribose) Polimerases/genética , Domínios e Motivos de Interação entre Proteínas , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Supressoras de Tumor/química , Proteínas Supressoras de Tumor/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação
5.
Nat Rev Mol Cell Biol ; 21(5): 284-299, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32094664

RESUMO

The tumour suppressor breast cancer type 1 susceptibility protein (BRCA1) promotes DNA double-strand break (DSB) repair by homologous recombination and protects DNA replication forks from attrition. BRCA1 partners with BRCA1-associated RING domain protein 1 (BARD1) and other tumour suppressor proteins to mediate the initial nucleolytic resection of DNA lesions and the recruitment and regulation of the recombinase RAD51. The discovery of the opposing functions of BRCA1 and the p53-binding protein 1 (53BP1)-associated complex in DNA resection sheds light on how BRCA1 influences the choice of homologous recombination over non-homologous end joining and potentially other mutagenic pathways of DSB repair. Understanding the functional crosstalk between BRCA1-BARD1 and its cofactors and antagonists will illuminate the molecular basis of cancers that arise from a deficiency or misregulation of chromosome damage repair and replication fork maintenance. Such knowledge will also be valuable for understanding acquired tumour resistance to poly(ADP-ribose) polymerase (PARP) inhibitors and other therapeutics and for the development of new treatments. In this Review, we discuss recent advances in elucidating the mechanisms by which BRCA1-BARD1 functions in DNA repair, replication fork maintenance and tumour suppression, and its therapeutic relevance.


Assuntos
Proteína BRCA1/genética , Neoplasias da Mama/genética , Proteínas Supressoras de Tumor/genética , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/genética , Ubiquitina-Proteína Ligases/genética , Neoplasias da Mama/patologia , Reparo do DNA por Junção de Extremidades/genética , Replicação do DNA/genética , Feminino , Humanos , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Poli(ADP-Ribose) Polimerases/genética , Ligação Proteica/genética , Reparo de DNA por Recombinação/genética
6.
J Hum Genet ; 65(3): 209-220, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31907386

RESUMO

The clinical utility of BRCA1/2 genotyping was recently extended from the selection of subjects at high risk for hereditary breast and ovary cancer to the identification of candidates for poly (ADP-ribose) polymerase (PARP) inhibitor treatment. This underscores the importance of accurate interpretation of BRCA1/2 genetic variants and of reducing the number of variants of uncertain significance (VUSs). Two recent studies by Findlay et al. and Starita et al. introduced high-throughput functional assays, and proactively analyzed variants in specific regions regardless of whether they had been previously observed. We retrospectively reviewed all BRCA1 and BRCA2 germline genetic test reports from patients with breast or ovarian cancer examined at Asan Medical Center (Seoul, Korea) between September 2011 and December 2018. Variants were assigned pathogenic or benign strong evidence codes according to the functional classification and were reclassified according to the ACMG/AMP 2015 guidelines. Among 3684 patients with available BRCA1 and BRCA2 germline genetic test reports, 429 unique variants (181 from BRCA1) were identified. Of 34 BRCA1 variants intersecting with the data reported by Findlay et al., three missense single-nucleotide variants from four patients (0.11%, 4/3684) were reclassified from VUSs to likely pathogenic variants. Four variants scored as functional were reclassified into benign or likely benign variants. Three variants that overlapped with the data reported by Starita et al. could not be reclassified. In conclusion, proactive high-throughput functional study data are useful for the reclassification of clinically observed VUSs. Integrating additional evidence, including functional assay results, may help reduce the number of VUSs.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/genética , Neoplasias Ovarianas/genética , Adulto , Idoso , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/patologia , Feminino , Predisposição Genética para Doença , Testes Genéticos , Variação Genética/genética , Genótipo , Mutação em Linhagem Germinativa/genética , Humanos , Pessoa de Meia-Idade , Mutação de Sentido Incorreto/genética , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/epidemiologia , Neoplasias Ovarianas/patologia , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Poli(ADP-Ribose) Polimerases/genética , República da Coreia/epidemiologia
8.
Pharmacogenomics ; 21(1): 75-81, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31849283

RESUMO

Our current understanding of prostate cancer pharmacogenomics is growing at a rapid pace. Apart from evaluating relevant biomarkers and genomic alterations in tumor tissues, an increasing focus is being placed on decoding the impact of germline alterations on prostate cancer and its treatment. Herein we summarize various germline variants that have shown to associate with response to systemic therapy in men with advanced prostate cancer. Covered biomarkers include HSD3B1, SLCO2B1, SULT1E1, TRMT11, CYP17A1, CYP1B1, genes involved in homologous recombination and DNA mismatch repair.


Assuntos
Complexos Multienzimáticos/genética , Transportadores de Ânions Orgânicos/genética , Progesterona Redutase/genética , Neoplasias da Próstata/tratamento farmacológico , Esteroide 17-alfa-Hidroxilase/genética , Esteroide Isomerases/genética , Biomarcadores Tumorais/genética , Reparo de Erro de Pareamento de DNA/genética , Reparo do DNA/efeitos dos fármacos , Células Germinativas/efeitos dos fármacos , Mutação em Linhagem Germinativa/efeitos dos fármacos , Recombinação Homóloga/genética , Humanos , Masculino , Poli(ADP-Ribose) Polimerases/genética , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia
9.
Chem Biol Interact ; 316: 108932, 2020 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-31874162

RESUMO

The incidence and mortality of lung cancer are the highest among cancer-related deaths. However, the long-term use of currently available cytotoxic drugs can increase genetic alterations in cancer cells and cause drug-resistance, which significantly limits their usage. Since current systemic treatment options are limited, effective chemotherapeutic agents are urgently needed for non-small cell lung cancer (NSCLC) treatment. In this study, we demonstrated that ganoderic acid DM (GA-DM) could increase apoptosis in A549 and NCI-H460 NSCLC cells. GA-DM treatment decreased the protein expression levels of Bcl-2 and increased the expression levels of Bax, cleaved caspase-3 and cleaved PRAP. Furthermore, GA-DM could promote autophagic flux, and the cytotoxic effect against cancer cells of GA-DM was significantly inhibited by targeted suppression of autophagy, suggesting that autophagy contributed to GA-DM-induced cell death in NSCLC. Moreover, GA-DM clearly induced autophagy by inactivating the PI3K/Akt/mTOR pathway. When overexpression of Akt reactivated Akt/mTOR pathway in A549 or NCI-H460 cells, the increase of autophagy related marker LC3B-II and apoptosis related protein cleaved PARP and cleaved caspase 3 and the ration of apoptotic cells by GA-DM was reversed, suggesting that GA-DM promoted autophagy and apoptosis by inhibiting Akt/mTOR pathway-mediated autophagy induction. In conclusion, our study indicated that GA-DM can induce autophagic apoptosis in NSCLC by inhibiting Akt/mTOR activity. (209 words).


Assuntos
Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Triterpenos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Caspase 3/metabolismo , Linhagem Celular Tumoral , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Poli(ADP-Ribose) Polimerases/genética , Poli(ADP-Ribose) Polimerases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Serina-Treonina Quinases TOR/metabolismo
10.
Nature ; 576(7786): 274-280, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31802000

RESUMO

Embryonal tumours with multilayered rosettes (ETMRs) are aggressive paediatric embryonal brain tumours with a universally poor prognosis1. Here we collected 193 primary ETMRs and 23 matched relapse samples to investigate the genomic landscape of this distinct tumour type. We found that patients with tumours in which the proposed driver C19MC2-4 was not amplified frequently had germline mutations in DICER1 or other microRNA-related aberrations such as somatic amplification of miR-17-92 (also known as MIR17HG). Whole-genome sequencing revealed that tumours had an overall low recurrence of single-nucleotide variants (SNVs), but showed prevalent genomic instability caused by widespread occurrence of R-loop structures. We show that R-loop-associated chromosomal instability can be induced by the loss of DICER1 function. Comparison of primary tumours and matched relapse samples showed a strong conservation of structural variants, but low conservation of SNVs. Moreover, many newly acquired SNVs are associated with a mutational signature related to cisplatin treatment. Finally, we show that targeting R-loops with topoisomerase and PARP inhibitors might be an effective treatment strategy for this deadly disease.


Assuntos
MicroRNAs/genética , Neoplasias Embrionárias de Células Germinativas/genética , RNA Helicases DEAD-box/genética , DNA Topoisomerases Tipo I/genética , Humanos , Mutação , Neoplasias Embrionárias de Células Germinativas/diagnóstico , Inibidores de Poli(ADP-Ribose) Polimerases , Poli(ADP-Ribose) Polimerases/genética , Polimorfismo de Nucleotídeo Único , Recidiva , Ribonuclease III/genética
11.
Nat Commun ; 10(1): 5654, 2019 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-31827085

RESUMO

Poly(ADP-ribose)ylation (PARylation) by PAR polymerase 1 (PARP1) and PARylation removal by poly(ADP-ribose) glycohydrolase (PARG) critically regulate DNA damage responses; yet, conflicting reports obscure PARG biology and its impact on cancer cell resistance to PARP1 inhibitors. Here, we found that PARG expression is upregulated in many cancers. We employed chemical library screening to identify and optimize methylxanthine derivatives as selective bioavailable PARG inhibitors. Multiple crystal structures reveal how substituent positions on the methylxanthine core dictate binding modes and inducible-complementarity with a PARG-specific tyrosine clasp and arginine switch, supporting inhibitor specificity and a competitive inhibition mechanism. Cell-based assays show selective PARG inhibition and PARP1 hyperPARylation. Moreover, our PARG inhibitor sensitizes cells to radiation-induced DNA damage, suppresses replication fork progression and impedes cancer cell survival. In PARP inhibitor-resistant A172 glioblastoma cells, our PARG inhibitor shows comparable killing to Nedaplatin, providing further proof-of-concept that selectively inhibiting PARG can impair cancer cell survival.


Assuntos
Replicação do DNA/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Glicosídeo Hidrolases/antagonistas & inibidores , Neoplasias/genética , Bibliotecas de Moléculas Pequenas/farmacologia , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Inibidores Enzimáticos/química , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Humanos , Neoplasias/enzimologia , Neoplasias/metabolismo , Neoplasias/fisiopatologia , Poli ADP Ribosilação/efeitos dos fármacos , Poli(ADP-Ribose) Polimerases/genética , Poli(ADP-Ribose) Polimerases/metabolismo , Bibliotecas de Moléculas Pequenas/química
12.
J Agric Food Chem ; 67(46): 12761-12769, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31675233

RESUMO

There is convincing evidence that consuming whole grains (WGs) may decrease the risk of colorectal cancer (CRC). Wheat bran (WB) is a rich source of dietary fiber and phytochemicals with health-promoting properties. However, the active components especially the interaction between different components in WG wheat have not been fully explored. Here, we investigated whether one of the major WB phytochemicals, alkylresorcinol (AR) C21, and the major active intestinal microbial metabolite of fiber, butyrate, could synergistically suppress human colon cancer cells. Our results demonstrated for the first time that the combination of C21 and butyrate synergistically inhibited the growth of human colon cancer cells and induced apoptosis. Further mechanistic studies demonstrated that the cotreatment of C21 and butyrate induced significant up-regulations in cleaved Poly(ADP-ribose) polymerase (PARP), cleaved caspase 3, p53 upregulated modulator of apoptosis (PUMA), cytochrome C, lipid-conjugated membrane-bound form of microtubule-associated protein 1A/1B-light chain 3 (LC3-II), and C/EBP homologous protein (CHOP) expressions, indicating the synergistic anticancer effects of C21 and butyrate were associated with induction of apoptosis, autophagy, and ER stress pathways. Notably, the C21 concentrations in the large intestinal tract of mice treated with human relevant doses of C21, were from 0.86 to 1.78 µmol/g, suggesting the C21 doses used in vitro may be achievable after daily WG wheat intake. These results provide novel insights into the dietary prevention of CRC regarding the potential interaction of bioactive WG wheat phytochemicals and the microbial metabolites of fiber.


Assuntos
Butiratos/metabolismo , Neoplasias do Colo/tratamento farmacológico , Fibras na Dieta/análise , Microbioma Gastrointestinal/efeitos dos fármacos , Intestinos/microbiologia , Compostos Fitoquímicos/administração & dosagem , Resorcinóis/administração & dosagem , Animais , Autofagia/efeitos dos fármacos , Caspase 3/genética , Caspase 3/metabolismo , Linhagem Celular Tumoral , Neoplasias do Colo/metabolismo , Neoplasias do Colo/microbiologia , Neoplasias do Colo/fisiopatologia , Humanos , Intestinos/efeitos dos fármacos , Masculino , Camundongos , Compostos Fitoquímicos/química , Poli(ADP-Ribose) Polimerases/genética , Poli(ADP-Ribose) Polimerases/metabolismo , Resorcinóis/química
13.
BMC Complement Altern Med ; 19(1): 274, 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31638961

RESUMO

BACKGROUND: Recent research has suggested that autophagy can provide a better mechanism for inducing cell death than current therapeutic strategies. This study investigated the effects of using an ethanol extract of Chrysanthemum zawadskii Herbich (ECZ) to induce apoptosis and autophagy associated with reliable signal pathways in mouse colon cancer CT-26 cells. METHODS: Using ECZ on mouse colon cancer CT-26 cells, cell viability, annexin V/propidium iodide staining, acridine orange staining, reactive oxygen species (ROS) and western blotting were assayed. RESULTS: ECZ exhibited cytotoxicity in CT-26 cells in a dose-dependent manner. ECZ induced apoptosis was confirmed by caspase-3 activation, poly (ADP-ribose) polymerase cleavage, and increased production of reactive oxygen species (ROS). Furthermore, it was shown that ECZ induced autophagy via the increased conversion of microtubule-associated protein 1 light chain 3II, the degradation of p62, and the formation of acidic vesicular organelles. The inhibition of ROS production by N-Acetyl-L-cysteine resulted in reduced ECZ-induced apoptosis and autophagy. Furthermore, the inhibition of autophagy by 3-methyladenine resulted in enhanced ECZ-induced apoptosis via increased ROS generation. CONCLUSION: These findings confirmed that ECZ induced ROS-mediated autophagy and apoptosis in colon cancer cells. Therefore, ECZ may serve as a novel potential chemotherapeutic candidate for colon cancer.


Assuntos
Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Chrysanthemum/química , Neoplasias do Colo/fisiopatologia , Extratos Vegetais/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Animais , Caspase 3/genética , Caspase 3/metabolismo , Linhagem Celular Tumoral , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/genética , Neoplasias do Colo/metabolismo , Humanos , Camundongos , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Extratos Vegetais/isolamento & purificação , Poli(ADP-Ribose) Polimerases/genética , Poli(ADP-Ribose) Polimerases/metabolismo
14.
Mol Cell ; 75(6): 1286-1298.e12, 2019 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-31473101

RESUMO

Long interspersed element-1 (LINE-1 or L1) retrotransposition poses a threat to genome integrity, and cells have evolved mechanisms to restrict retrotransposition. However, how cellular proteins facilitate L1 retrotransposition requires elucidation. Here, we demonstrate that single-strand DNA breaks induced by the L1 endonuclease trigger the recruitment of poly(ADP-ribose) polymerase 2 (PARP2) to L1 integration sites and that PARP2 activation leads to the subsequent recruitment of the replication protein A (RPA) complex to facilitate retrotransposition. We further demonstrate that RPA directly binds activated PARP2 through poly(ADP-ribosyl)ation and can protect single-strand L1 integration intermediates from APOBEC3-mediated cytidine deamination in vitro. Paradoxically, we provide evidence that RPA can guide APOBEC3A, and perhaps other APOBEC3 proteins, to sites of L1 integration. Thus, the interplay of L1-encoded and evolutionarily conserved cellular proteins is required for efficient retrotransposition; however, these interactions also may be exploited to restrict L1 retrotransposition in the human genome.


Assuntos
Elementos Nucleotídeos Longos e Dispersos , Poli(ADP-Ribose) Polimerases/metabolismo , Proteína de Replicação A/metabolismo , Animais , Células CHO , Cricetulus , Citidina Desaminase/genética , Citidina Desaminase/metabolismo , Células HEK293 , Células HeLa , Humanos , Poli(ADP-Ribose) Polimerases/genética , Ligação Proteica , Proteína de Replicação A/genética
15.
BMC Plant Biol ; 19(1): 364, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31426748

RESUMO

BACKGROUND: Poly (ADP-ribosyl) ation (PARylation) is an important posttranslational modification that regulates DNA repair, gene transcription, stress responses and developmental processes in multicellular organisms. Poly (ADP-ribose) polymerase (PARP) catalyzes PARylation by consecutively adding ADP-ribose moieties from NAD+ to the amino acid receptor residues on target proteins. Arabidopsis has three canonical PARP members, and two of these members, AtPARP1 and AtPARP2, have been demonstrated to be bona fide poly (ADP-ribose) polymerases and to regulate DNA repair and stress response processes. However, it remains unknown whether AtPARP3, a member that is highly expressed in seeds, has similar biochemical activity to that of AtPARP1 and AtPARP2. Additionally, although both the phylogenetic relationships and structural similarities indicate that AtPARP1 and AtPARP2 correspond to animal PARP1 and PARP2, respectively, two previous studies have indicated that AtPARP2, and not AtPARP1, accounts for most of the PARP activity in Arabidopsis, which is contrary to the knowledge that PARP1 is the predominant PARP in animals. RESULTS: In this study, we obtained both in vitro and in vivo evidence demonstrating that AtPARP3 does not act as a typical PARP in Arabidopsis. Domain swapping and point mutation assays indicated that AtPARP3 has lost NAD+-binding capability and is inactive. In addition, our results showed that AtPARP1 was responsible for most of the PARP enzymatic activity in response to the DNA damage-inducing agents zeocin and methyl methanesulfonate (MMS) and was more rapidly activated than AtPARP2, which supports that AtPARP1 remains the predominant PARP member in Arabidopsis. AtPARP1 might first become activated by binding to damaged sites, and AtPARP2 is then poly (ADP-ribosyl) ated by AtPARP1 in vivo. CONCLUSIONS: Collectively, our biochemical and genetic analysis results strongly support the notion that AtPARP3 has lost poly (ADP-ribose) polymerase activity in plants and performs different functions from those of AtPARP1 and AtPARP2. AtPARP1, instead of AtPARP2, plays the predominant role in PAR synthesis in both seeds and seedlings. These data bring new insights into our understanding of the physiological functions of plant PARP family members.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Dano ao DNA/genética , Reparo do DNA/genética , Poli(ADP-Ribose) Polimerase-1/genética , Poli(ADP-Ribose) Polimerases/genética , Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Bleomicina/farmacologia , Metanossulfonato de Metila/farmacologia , Mutagênicos/farmacologia , Poli(ADP-Ribose) Polimerase-1/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/metabolismo
16.
Mutat Res ; 780: 82-91, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31395352

RESUMO

Poly(ADP-ribosyl)ation (aka PARylation) is a unique protein post-translational modification (PTM) first described over 50 years ago. PARylation regulates a number of biological processes including chromatin remodeling, the DNA damage response (DDR), transcription, apoptosis, and mitosis. The subsequent discovery of poly(ADP-ribose) polymerase-1 (PARP-1) catalyzing DNA-dependent PARylation spearheaded the field of DDR. The expanding knowledge about the poly ADP-ribose (PAR) recognition domains prompted the discovery of novel DDR factors and revealed crosstalk with other protein PTMs including phosphorylation, ubiquitination, methylation and acetylation. In this review, we highlight the current knowledge on PAR-regulated DDR, PAR recognition domain, and PARP inhibition in cancer therapy.


Assuntos
Dano ao DNA/genética , Neoplasias/genética , Poli ADP Ribosilação/genética , Poli Adenosina Difosfato Ribose/genética , Animais , Dano ao DNA/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Reparo do DNA/genética , Humanos , Neoplasias/tratamento farmacológico , Poli ADP Ribosilação/efeitos dos fármacos , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Poli(ADP-Ribose) Polimerases/genética
17.
Bioengineered ; 10(1): 374-382, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31431131

RESUMO

The aim of the present study was to investigate the anticancer effects and potential mechanisms of polyphenol epigallocatechin-3-gallate (EGCG) on breast cancer MCF-7 cells in vitro and in vivo. Our results showed that EGCG significantly inhibited MCF-7 cell viability in a time- and dose-dependent manner. Flow cytometry analysis indicated that EGCG induced apoptosis and disrupted cell cycle progression at G2/M phase. Moreover, EGCG inhibited miR-25 expression and increased PARP, pro-caspase-3 and pro-caspase-9 at protein levels. Restoration of miR-25 inhibited EGCG-induced cell apoptosis. Furthermore, EGCG suppressed tumor growth in vivo by downregulating the expression of miR-25 and proteins associated with apoptosis, which was further confirmed by a reduction of Ki-67 and increase of pro-apoptotic PARP expression as determined by immunohistochemistry staining. These findings indicate that EGCG possesses chemopreventive potential in breast cancer which may serve as a promising anticancer agent for clinical applications.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Catequina/análogos & derivados , Proliferação de Células/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Caspase 3/genética , Caspase 3/metabolismo , Caspase 9/genética , Caspase 9/metabolismo , Catequina/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Pontos de Checagem da Fase G2 do Ciclo Celular/genética , Humanos , Antígeno Ki-67/genética , Antígeno Ki-67/metabolismo , Células MCF-7 , Camundongos , Camundongos SCID , MicroRNAs/antagonistas & inibidores , MicroRNAs/metabolismo , Poli(ADP-Ribose) Polimerases/genética , Poli(ADP-Ribose) Polimerases/metabolismo , Transdução de Sinais , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
18.
BMC Cancer ; 19(1): 731, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31340767

RESUMO

BACKGROUND: Emerging evidence indicates that Long non-coding RNAs (LncRNAs) and microRNAs (miRNAs) play crucial roles in tumor progression, including hepatocellular carcinoma (HCC). However, whether there is a crosstalk between LncRNA pituitary tumor-transforming 3 (PTTG3P) and miR-383 in HCC remains unknown. This study is designed to explore the underlying mechanism by which LncRNA PTTG3P sponges miR-383 during HCC progression. METHODS: qPCR and Western blot were used to analyze LncRNA PTTG3P, miR-383 and other target genes' expression. CCK-8 assay was performed to examine cell proliferation. Annexin V-PE/PI and PI staining were used to analyze cell apoptosis and cell cycle distribution by flow cytometry, respectively. Transwell migration and invasion assays were used to examine cell migration and invasion abilities. An in vivo xenograft study was performed to detect tumor growth. Luciferase reporter assay and RNA pull-down assay were carried out to detect the interaction between miR-383 and LncRNA PTTG3P. RIP was carried out to detect whether PTTG3P and miR-383 were enriched in Ago2-immunoprecipitated complex. RESULTS: In this study, we found that PTTG3P was up-regulated in HCC tissues and cells. Functional experiments demonstrated that knockdown of PTTG3P inhibited cell proliferation, migration and invasion, and promoted cell apoptosis, acting as an oncogene. Mechanistically, PTTG3P upregulated the expression of miR-383 targets Cyclin D1 (CCND1) and poly ADP-ribose polymerase 2 (PARP2) by sponging miR-383, acting as a competing endogenous RNA (ceRNA). The PTTG3P-miR-383-CCND1/PARP2 axis modulated HCC phenotypes. Moreover, PTTG3P also affected the PI3K/Akt signaling pathway. CONCLUSION: The data indicate a novel PTTG3P-miR-383-CCND1/PARP2 axis in HCC tumorigenesis, suggesting that PTTG3P may be used as a potential therapeutic target in HCC.


Assuntos
Carcinoma Hepatocelular/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/genética , MicroRNAs/genética , RNA Longo não Codificante/metabolismo , Apoptose/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Ciclina D1/genética , Feminino , Técnicas de Silenciamento de Genes , Humanos , Fígado/patologia , Neoplasias Hepáticas/patologia , Masculino , MicroRNAs/metabolismo , Pessoa de Meia-Idade , Invasividade Neoplásica/genética , Oncogenes , Poli(ADP-Ribose) Polimerases/genética , RNA Longo não Codificante/genética , Regulação para Cima
19.
Genes (Basel) ; 10(8)2019 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-31357527

RESUMO

Prostate cancer is globally the second most commonly diagnosed cancer type in men. Recent studies suggest that mutations in DNA repair genes are associated with aggressive forms of prostate cancer and castration resistance. Prostate cancer with DNA repair defects may be vulnerable to therapeutic targeting by Poly(ADP-ribose) polymerase (PARP) inhibitors. PARP enzymes modify target proteins with ADP-ribose in a process called PARylation and are in particular involved in single strand break repair. The rationale behind the clinical trials that led to the current use of PARP inhibitors to treat cancer was to target the dependence of BRCA-mutant cancer cells on the PARP-associated repair pathway due to deficiency in homologous recombination. However, recent studies have proposed therapeutic potential for PARP inhibitors in tumors with a variety of vulnerabilities generating dependence on PARP beyond the synthetic lethal targeting of BRCA1/BRCA2 mutated tumors, suggesting a wider potential than initially thought. Importantly, PARP-associated DNA repair pathways are also closely connected to androgen receptor (AR) signaling, which is a key regulator of tumor growth and a central therapeutic target in prostate cancer. In this review, we provide an extensive overview of published and ongoing trials exploring PARP inhibitors in treatment of prostate cancer and discuss the underlying biology. Several clinical trials are currently studying PARP inhibitor mono- and combination therapies in the treatment of prostate cancer. Integration of drugs targeting DNA repair pathways in prostate cancer treatment modalities allows developing of more personalized care taking also into account the genetic makeup of individual tumors.


Assuntos
Antineoplásicos/uso terapêutico , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Neoplasias da Próstata/genética , Animais , Ensaios Clínicos como Assunto , Avaliação Pré-Clínica de Medicamentos , Humanos , Masculino , Poli(ADP-Ribose) Polimerases/genética , Poli(ADP-Ribose) Polimerases/metabolismo , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/metabolismo
20.
Nucleic Acids Res ; 47(16): 8548-8562, 2019 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-31276581

RESUMO

Cockayne syndrome is an accelerated aging disorder, caused by mutations in the CSA or CSB genes. In CSB-deficient cells, poly (ADP ribose) polymerase (PARP) is persistently activated by unrepaired DNA damage and consumes and depletes cellular nicotinamide adenine dinucleotide, which leads to mitochondrial dysfunction. Here, the distribution of poly (ADP ribose) (PAR) was determined in CSB-deficient cells using ADPr-ChAP (ADP ribose-chromatin affinity purification), and the results show striking enrichment of PAR at transcription start sites, depletion of heterochromatin and downregulation of H3K9me3-specific methyltransferases SUV39H1 and SETDB1. Induced-expression of SETDB1 in CSB-deficient cells downregulated PAR and normalized mitochondrial function. The results suggest that defects in CSB are strongly associated with loss of heterochromatin, downregulation of SETDB1, increased PAR in highly-transcribed regions, and mitochondrial dysfunction.


Assuntos
Senescência Celular/genética , Síndrome de Cockayne/genética , DNA Helicases/genética , Enzimas Reparadoras do DNA/genética , Histonas/genética , Mitocôndrias/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/genética , Metiltransferases de Proteína/genética , Fatores de Transcrição/genética , Linhagem Celular Transformada , Cromatina/química , Cromatina/metabolismo , Síndrome de Cockayne/metabolismo , Síndrome de Cockayne/patologia , DNA/genética , DNA/metabolismo , Dano ao DNA , DNA Helicases/metabolismo , Enzimas Reparadoras do DNA/metabolismo , Fibroblastos/metabolismo , Fibroblastos/patologia , Regulação da Expressão Gênica , Histonas/metabolismo , Humanos , Metiltransferases/genética , Metiltransferases/metabolismo , Mitocôndrias/patologia , Mutação , NAD/metabolismo , Poli Adenosina Difosfato Ribose/metabolismo , Poli(ADP-Ribose) Polimerases/genética , Poli(ADP-Ribose) Polimerases/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , Metiltransferases de Proteína/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo , Sítio de Iniciação de Transcrição , Transcrição Genética
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