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1.
BMC Bioinformatics ; 21(Suppl 14): 408, 2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-32998723

RESUMO

BACKGROUND: Second messengers, c-di-GMP and (p)ppGpp, are vital regulatory molecules in bacteria, influencing cellular processes such as biofilm formation, transcription, virulence, quorum sensing, and proliferation. While c-di-GMP and (p)ppGpp are both synthesized from GTP molecules, they play antagonistic roles in regulating the cell cycle. In C. crescentus, c-di-GMP works as a major regulator of pole morphogenesis and cell development. It inhibits cell motility and promotes S-phase entry by inhibiting the activity of the master regulator, CtrA. Intracellular (p)ppGpp accumulates under starvation, which helps bacteria to survive under stressful conditions through regulating nucleotide levels and halting proliferation. (p)ppGpp responds to nitrogen levels through RelA-SpoT homolog enzymes, detecting glutamine concentration using a nitrogen phosphotransferase system (PTS Ntr). This work relates the guanine nucleotide-based second messenger regulatory network with the bacterial PTS Ntr system and investigates how bacteria respond to nutrient availability. RESULTS: We propose a mathematical model for the dynamics of c-di-GMP and (p)ppGpp in C. crescentus and analyze how the guanine nucleotide-based second messenger system responds to certain environmental changes communicated through the PTS Ntr system. Our mathematical model consists of seven ODEs describing the dynamics of nucleotides and PTS Ntr enzymes. Our simulations are consistent with experimental observations and suggest, among other predictions, that SpoT can effectively decrease c-di-GMP levels in response to nitrogen starvation just as well as it increases (p)ppGpp levels. Thus, the activity of SpoT (or its homologues in other bacterial species) can likely influence the cell cycle by influencing both c-di-GMP and (p)ppGpp. CONCLUSIONS: In this work, we integrate current knowledge and experimental observations from the literature to formulate a novel mathematical model. We analyze the model and demonstrate how the PTS Ntr system influences (p)ppGpp, c-di-GMP, GMP and GTP concentrations. While this model does not consider all aspects of PTS Ntr signaling, such as cross-talk with the carbon PTS system, here we present our first effort to develop a model of nutrient signaling in C. crescentus.


Assuntos
Caulobacter crescentus/fisiologia , Modelos Teóricos , Sistemas do Segundo Mensageiro , Pontos de Checagem do Ciclo Celular , GMP Cíclico/análogos & derivados , GMP Cíclico/metabolismo , Nitrogênio/metabolismo , Fosfotransferases/metabolismo , Sistemas do Segundo Mensageiro/fisiologia
2.
Anticancer Res ; 40(10): 5517-5527, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32988875

RESUMO

BACKGROUND/AIM: Drug resistance is a significant cause of high mortality in ovarian cancer (OC) patients. The reverse transcriptase inhibitor azidothymidine (AZT) has been utilized as a treatment for tumors, but its role in OC treatment has not been revealed. The aim of the present in vitro study was to examine the influence of AZT on the growth of human OC cells and the involved proteins. MATERIALS AND METHODS: The proliferation, cell cycle distribution, extent of apoptosis, mitotic index, and terminal restriction fragment length were examined in three OC cell lines, CaOV3, TOV112D, and TOV21G, treated with AZT. RESULTS: AZT inhibited growth of the TOV21G and CaOV3 cell lines by regulating cell cycle distribution. Specifically, AZT caused G2/M phase arrest on TOV21G cells and S phase arrest on CaOV3 cells. In addition, AZT treatment induced up-regulation of p21 and p16 in the TOV21G and CaOV3 cell line, respectively. CONCLUSION: AZT inhibited cell proliferation in serous and clear cell OC via the regulation of cell cycle distribution.


Assuntos
Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Neoplasias Ovarianas/tratamento farmacológico , Zidovudina/farmacologia , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Feminino , Humanos , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia
3.
Nat Commun ; 11(1): 4709, 2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32948765

RESUMO

Glioblastoma cancer-stem like cells (GSCs) display marked resistance to ionizing radiation (IR), a standard of care for glioblastoma patients. Mechanisms underpinning radio-resistance of GSCs remain largely unknown. Chromatin state and the accessibility of DNA lesions to DNA repair machineries are crucial for the maintenance of genomic stability. Understanding the functional impact of chromatin remodeling on DNA repair in GSCs may lay the foundation for advancing the efficacy of radio-sensitizing therapies. Here, we present the results of a high-content siRNA microscopy screen, revealing the transcriptional elongation factor SPT6 to be critical for the genomic stability and self-renewal of GSCs. Mechanistically, SPT6 transcriptionally up-regulates BRCA1 and thereby drives an error-free DNA repair in GSCs. SPT6 loss impairs the self-renewal, genomic stability and tumor initiating capacity of GSCs. Collectively, our results provide mechanistic insights into how SPT6 regulates DNA repair and identify SPT6 as a putative therapeutic target in glioblastoma.


Assuntos
Reparo do DNA , Instabilidade Genômica , Glioblastoma/genética , Células-Tronco Neoplásicas , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Animais , Apoptose , Proteína BRCA1 , Neoplasias Encefálicas/genética , Pontos de Checagem do Ciclo Celular , Linhagem Celular Tumoral , Feminino , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Inativação Gênica , Glioblastoma/patologia , Células HEK293 , Xenoenxertos , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Células-Tronco Neoplásicas/patologia , RNA Interferente Pequeno/genética , Tolerância a Radiação , Radiação Ionizante , Transcriptoma
4.
Anticancer Res ; 40(9): 4979-4987, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32878786

RESUMO

BACKGROUND/AIM: Multiple myeloma is a highly heterogeneous disease of clonal plasma cells. Histone deacetylase (HDAC) inhibitors are promising anticancer drugs but their precise mechanisms of actions are not well understood. MATERIALS AND METHODS: Cell-cycle regulation and pro-apoptotic effects of two histone deacetylase inhibitors, suberohydroxamic acid (SAHA) and suberoylanilide hydroxamic acid (SBHA), were analyzed in multiple myeloma cell lines RPMI8226 and U266 with differing TP53 status using gene-expression analysis. RESULTS: Enhanced expression of cyclin-dependent kinase inhibitor 1A (CDKN1A/p21WAF/CIP1) detected in the TP53-deleted U266 cell line after SAHA treatment indicates the P53-independent mode of transcriptional activation of CDKN1A gene. In contrast, CDKN1A gene expression was significantly increased by both SBHA and SAHA treatment of TP53-mutated RPMI8226 cells. CONCLUSION: SAHA appears to be a potentially effective pro-apoptotic and anticancer drug with universal application in the treatment of heterogeneous populations of multiple myeloma cells.


Assuntos
Inibidor de Quinase Dependente de Ciclina p21/genética , Mieloma Múltiplo/patologia , Proteína Supressora de Tumor p53/metabolismo , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p21/antagonistas & inibidores , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Inibidores de Histona Desacetilases/farmacologia , Humanos , Ácidos Hidroxâmicos/farmacologia , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Proteína Supressora de Tumor p53/genética
5.
Anticancer Res ; 40(9): 5191-5200, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32878807

RESUMO

BACKGROUND/AIM: Colorectal cancer is one of the most common malignancies worldwide. Small molecule-based chemotherapy is an attractive approach for the chemoprevention and treatment of colorectal cancer. Methylsulfonylmethane (MSM) is a natural organosulfur compound with anticancer properties, as revealed by studies on in vitro models of gingival, prostate, lung, hepatic, and breast cancer. However, the molecular mechanisms underlying the effects of MSM in colon cancer cells remain unclear. MATERIALS AND METHODS: Here, we investigated the effects of MSM, especially on the cell cycle arrest and apoptosis, in HT-29 cells. RESULTS: MSM suppressed the viability of HT-29 cells by inducing apoptosis and cell cycle arrest at the G0/G1 phase. MSM suppressed the sphere-forming ability and expression of stemness markers in HT-29 cells. CONCLUSION: MSM has anti-cancer effects on HT-29 cells, and induces cell cycle arrest and apoptosis, while suppressing the stemness potential.


Assuntos
Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Autorrenovação Celular/efeitos dos fármacos , Dimetil Sulfóxido/farmacologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Sulfonas/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Células HT29 , Humanos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Esferoides Celulares , Células Tumorais Cultivadas
6.
Tumour Biol ; 42(9): 1010428320954735, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32873193

RESUMO

Acute myeloid leukemia is the most common form of acute leukemia in adults, constituting about 80% of cases. Although remarkable progress has been made in the therapeutic scenario for patients with acute myeloid leukemia, research and development of new and effective anticancer agents to improve patient outcome and minimize toxicity is needed. In this study, the antitumor activity of axolotl (AXO) Ambystoma mexicanum crude extract was assessed in vitro on the human acute myeloid leukemia HL-60 cell line. The anticancer activity was evaluated in terms of ability to influence proliferative activity, cell viability, cell cycle arrest, and differentiation. Moreover, gene expression analysis was performed to evaluate the genes involved in the regulation of these processes. The AXO crude extract exhibited antiproliferative but not cytotoxic activities on HL-60 cells, with cell cycle arrest in the G0/G1 phase. Furthermore, the AXO-treated HL-60 cells showed an increase in both the percentage of nitroblue tetrazolium positive cells and the expression of CD11b, whereas the proportion of CD14-positive cells did not change, suggesting that extract is able to induce differentiation toward the granulocytic lineage. Finally, the treatment with AXO extract caused upregulation of CEBPA, CEBPB, CEBPE, SPI1, CDKN1A, and CDKN2C, and downregulation of c-MYC. Our data clearly show the potential anticancer activity of Ambystoma mexicanum on HL-60 cells and suggest that it could help develop promising therapeutic agents for the treatment of acute myeloid leukemia.


Assuntos
Ambystoma mexicanum , Proliferação de Células/efeitos dos fármacos , Misturas Complexas/farmacologia , Leucemia Mieloide Aguda/tratamento farmacológico , Animais , Proteína beta Intensificadora de Ligação a CCAAT/genética , Proteínas Estimuladoras de Ligação a CCAAT/genética , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p18/genética , Inibidor de Quinase Dependente de Ciclina p21/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HL-60 , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Proteínas Proto-Oncogênicas c-myc/genética
7.
Nat Commun ; 11(1): 4124, 2020 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-32807787

RESUMO

In response to DNA damage, a synthetic lethal relationship exists between the cell cycle checkpoint kinase MK2 and the tumor suppressor p53. Here, we describe the concept of augmented synthetic lethality (ASL): depletion of a third gene product enhances a pre-existing synthetic lethal combination. We show that loss of the DNA repair protein XPA markedly augments the synthetic lethality between MK2 and p53, enhancing anti-tumor responses alone and in combination with cisplatin chemotherapy. Delivery of siRNA-peptide nanoplexes co-targeting MK2 and XPA to pre-existing p53-deficient tumors in a highly aggressive, immunocompetent mouse model of lung adenocarcinoma improves long-term survival and cisplatin response beyond those of the synthetic lethal p53 mutant/MK2 combination alone. These findings establish a mechanism for co-targeting DNA damage-induced cell cycle checkpoints in combination with repair of cisplatin-DNA lesions in vivo using RNAi nanocarriers, and motivate further exploration of ASL as a generalized strategy to improve cancer treatment.


Assuntos
Pontos de Checagem do Ciclo Celular/fisiologia , Reparo do DNA/fisiologia , Animais , Pontos de Checagem do Ciclo Celular/genética , Linhagem Celular Tumoral , Dano ao DNA/genética , Dano ao DNA/fisiologia , Reparo do DNA/genética , Células HCT116 , Humanos , Immunoblotting , Camundongos , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Nanomedicina/métodos , Interferência de RNA , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo
8.
Nat Commun ; 11(1): 4345, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32859945

RESUMO

Chromosome movements and programmed DNA double-strand breaks (DSBs) promote homologue pairing and initiate recombination at meiosis onset. Meiotic progression involves checkpoint-controlled termination of these events when all homologue pairs achieve synapsis and form crossover precursors. Exploiting the temporo-spatial organisation of the C. elegans germline and time-resolved methods of protein removal, we show that surveillance of the synaptonemal complex (SC) controls meiotic progression. In nuclei with fully synapsed homologues and crossover precursors, removing different meiosis-specific cohesin complexes, which are individually required for SC stability, or a SC central region component causes functional redeployment of the chromosome movement and DSB machinery, triggering whole-nucleus reorganisation. This apparent reversal of the meiotic programme requires CHK-2 kinase reactivation via signalling from chromosome axes containing HORMA proteins, but occurs in the absence of transcriptional changes. Our results uncover an unexpected plasticity of the meiotic programme and show how chromosome signalling orchestrates nuclear organisation and meiotic progression.


Assuntos
Caenorhabditis elegans/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Estruturas Cromossômicas/metabolismo , Meiose/fisiologia , Animais , Proteínas de Caenorhabditis elegans/metabolismo , Pontos de Checagem do Ciclo Celular , Quinase do Ponto de Checagem 2/metabolismo , Pareamento Cromossômico , Quebras de DNA de Cadeia Dupla , Complexo Sinaptonêmico/metabolismo
9.
Nat Commun ; 11(1): 3987, 2020 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-32778678

RESUMO

Aneuploidy, the presence of an abnormal number of chromosomes, is a major cause of early pregnancy loss in humans. Yet, the developmental consequences of specific aneuploidies remain unexplored. Here, we determine the extent of post-implantation development of human embryos bearing common aneuploidies using a recently established culture platform. We show that while trisomy 15 and trisomy 21 embryos develop similarly to euploid embryos, monosomy 21 embryos exhibit high rates of developmental arrest, and trisomy 16 embryos display a hypo-proliferation of the trophoblast, the tissue that forms the placenta. Using human trophoblast stem cells, we show that this phenotype can be mechanistically ascribed to increased levels of the cell adhesion protein E-CADHERIN, which lead to premature differentiation and cell cycle arrest. We identify three cases of mosaicism in embryos diagnosed as full aneuploid by pre-implantation genetic testing. Our results present the first detailed analysis of post-implantation development of aneuploid human embryos.


Assuntos
Aneuploidia , Implantação do Embrião/genética , Embrião de Mamíferos , Desenvolvimento Embrionário , Antígenos CD/genética , Caderinas/genética , Caderinas/metabolismo , Adesão Celular , Pontos de Checagem do Ciclo Celular , Linhagem da Célula , Segregação de Cromossomos , Cromossomos Humanos Par 16 , Cromossomos Humanos Par 21 , Feminino , Genes erbB-1/genética , Testes Genéticos , Humanos , Monossomia , Mosaicismo , Gravidez , Células-Tronco , Trissomia
10.
PLoS One ; 15(7): e0234103, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645016

RESUMO

Cyclin-dependent kinases (CDKs) contribute to the cancer hallmarks of uncontrolled proliferation and increased survival. As a result, over the last two decades substantial efforts have been directed towards identification and development of pharmaceutical CDK inhibitors. Insights into the biological consequences of CDK inhibition in specific tumor types have led to the successful development of CDK4/6 inhibitors as treatments for certain types of breast cancer. More recently, a new generation of pharmaceutical inhibitors of CDK enzymes that regulate the transcription of key oncogenic and pro-survival proteins, including CDK9, have entered clinical development. Here, we provide the first disclosure of the chemical structure of fadraciclib (CYC065), a CDK inhibitor and clinical candidate designed by further optimization from the aminopurine scaffold of seliciclib. We describe its synthesis and mechanistic characterization. Fadraciclib exhibits improved potency and selectivity for CDK2 and CDK9 compared to seliciclib, and also displays high selectivity across the kinome. We show that the mechanism of action of fadraciclib is consistent with potent inhibition of CDK9-mediated transcription, decreasing levels of RNA polymerase II C-terminal domain serine 2 phosphorylation, the pro-survival protein Myeloid Cell Leukemia 1 (MCL1) and MYC oncoprotein, and inducing rapid apoptosis in cancer cells. This cellular potency and mechanism of action translate to promising anti-cancer activity in human leukemia mouse xenograft models. Studies of leukemia cell line sensitivity identify mixed lineage leukemia (MLL) gene status and the level of B-cell lymphoma 2 (BCL2) family proteins as potential markers for selection of patients with greater sensitivity to fadraciclib. We show that the combination of fadraciclib with BCL2 inhibitors, including venetoclax, is synergistic in leukemic cell models, as predicted from simultaneous inhibition of MCL1 and BCL2 pro-survival pathways. Fadraciclib preclinical pharmacology data support its therapeutic potential in CDK9- or CDK2-dependent cancers and as a rational combination with BCL2 inhibitors in hematological malignancies. Fadraciclib is currently in Phase 1 clinical studies in patients with advanced solid tumors (NCT02552953) and also in combination with venetoclax in patients with relapsed or refractory chronic lymphocytic leukemia (CLL) (NCT03739554) and relapsed refractory acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) (NCT04017546).


Assuntos
Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/farmacologia , Animais , Antineoplásicos/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Quinase 2 Dependente de Ciclina/efeitos dos fármacos , Quinase 2 Dependente de Ciclina/metabolismo , Quinase 9 Dependente de Ciclina/efeitos dos fármacos , Quinase 9 Dependente de Ciclina/metabolismo , Quinases Ciclina-Dependentes/antagonistas & inibidores , Humanos , Camundongos , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Sulfonamidas/farmacologia
11.
Toxicol Lett ; 332: 74-81, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32645459

RESUMO

Long-term exposure to benzene is associated with adverse health effects such as leukemia. Abnormal cell cycle progression has been reported participating in tumorigenesis. Our previous study found that lncRNA-OBFC2A was involved in benzene toxicity through regulating cell proliferation. However, the function of lncRNA-OBFC2A in the regulation of cell cycle remains obscure and the precise mechanisms need to be explored. In vitro study, results showed that benzene metabolic, 1,4-Benzoquinone (1,4-BQ), induced cell cycle arrest at the G1 phase accompanied with decreased expression of Cyclin D1 in a dose-dependently manner. Interestingly, lncRNA-OBFC2A overexpression was found in AHH-1 cells treated with 1,4-BQ and while interference with lncRNA-OBFC2A, the expression of Cyclin D1 were reversed. Further, we found that lncRNA-OBFC2A can interact with Smad3 to control cell cycle via modulating Cyclin D1 expression. In benzene exposed workers, the expression of lncRNA-OBFC2A and Smad3 increased while cyclin D1 decreased which was consistent with the in vitro experiment, meanwhile, the significant associations among them were also found. Thus, these findings indicate that lncRNA-OBFC2A targeted to Smad3 regulated cyclin D1 influences cell cycle arrest induced by 1,4-BQ. LncRNA-OBFC2A, Smad3 and Cyclin D1 as a set of biomarkers play important roles in benzene haematotoxicity.


Assuntos
Benzoquinonas/toxicidade , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Ciclina D1/efeitos dos fármacos , RNA Longo não Codificante/efeitos dos fármacos , Proteína Smad3/efeitos dos fármacos , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Fase G1/efeitos dos fármacos , Doenças Hematológicas/induzido quimicamente , Neoplasias Hematológicas/induzido quimicamente , Humanos , Proteômica
12.
Chem Biol Interact ; 328: 109201, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32717190

RESUMO

The caseinate and glycated caseinate generated from the transglutaminase-catalyzed reaction of caseinate and oligochitosan were digested using pepsin and trypsin, and the activity of the resultant digests was measured in rat intestinal epithelial cell line (IEC-6) using several biological responses as indicators. Compared with the caseinate digest, the glycated caseinate digest had similar contents in 17 amino acids but less reactable -NH2 contents, and 6.57 g glucosamine per kg protein; moreover, it showed higher activity in the cells (P < 0.05) to promote cell growth, accumulate the cell-cycle progression at the S-phase, and prevent the camptothecin-induced cell apoptosis. The glycated caseinate digest also showed higher differentiation activity in the cells than the caseinate digest, resulting in enhanced activities of the three brush-border membrane enzymes (P < 0.05) and increased microvilli on the cell surfaces. The real-time reverse transcription-polymerase chain reaction, Western-blot assay, and Dickkopf-1 (a receptor inhibitor of the Wnt/ß-catenin signaling pathway) were used to determine both gene and protein expression changes in the cells. A Wnt/ß-catenin signaling pathway responsible for these enhanced effects was proposed because the five genes (glycogen synthase kinase 3ß, Wnt3a, ß-catenin, c-Myc, and cyclin D1) and three proteins (nuclear and cytosolic ß-catenin, cyclin D1, and c-Myc) as part of this signaling pathway were regulated in the treated cells. The oligochitosan glycation of caseinate induced by transglutaminase is thus suggested endowing the peptic-tryptic caseinate digest with higher activity in the cells through its effects on the Wnt/ß-catenin signaling pathway.


Assuntos
Caseínas/metabolismo , Quitina/análogos & derivados , Enterócitos/metabolismo , Pepsina A/metabolismo , Tripsina/metabolismo , Via de Sinalização Wnt , Animais , Apoptose , Bovinos , Pontos de Checagem do Ciclo Celular , Diferenciação Celular/genética , Proliferação de Células , Sobrevivência Celular , Quitina/metabolismo , Enterócitos/citologia , Enterócitos/ultraestrutura , Regulação da Expressão Gênica/efeitos dos fármacos , Glicosilação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Via de Sinalização Wnt/efeitos dos fármacos , Via de Sinalização Wnt/genética
13.
Adv Cancer Res ; 148: 201-232, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32723564

RESUMO

Polyploid giant cancer cells (PGCC) constitute a dangerous subpopulation of cancer cells and are a driving force in cancer recurrence. These unique cells arise from diploid tumor cells in response to stress encountered in the tumor microenvironment or during cancer therapy. PGCC are greatly dedifferentiated, acquire pluripotency, and are able to replicate through a form of asymmetric division called neosis, which results in new populations that are themselves able to differentiate into new cell types or to re-establish tumors. Progeny tend to be more genetically unstable than the founding population due to the dysregulation required to transition through a PGCC state. Therefore, cancers that escape stressors through this mechanism tend to re-emerge with a more aggressive phenotype that is therapy resistant. This review focuses on the clinical significance of PGCC, the need for standardized nomenclature and molecular markers, as well as possible avenues to develop therapies aimed at PGCC and the process of neosis. The biology underlying the development of PGCC including cell cycle checkpoint dysregulation, stress responses, dedifferentiation, stemness and epithelial-mesenchymal transition is discussed.


Assuntos
Recidiva Local de Neoplasia/patologia , Neoplasias/patologia , Células-Tronco Neoplásicas/patologia , Poliploidia , Animais , Pontos de Checagem do Ciclo Celular , Transição Epitelial-Mesenquimal , Humanos , Microambiente Tumoral
14.
Science ; 369(6502): 466-471, 2020 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-32703881

RESUMO

Cell size is fundamental to cell physiology. For example, cell size determines the spatial scale of organelles and intracellular transport and thereby affects biosynthesis. Although some genes that affect mammalian cell size have been identified, the molecular mechanisms through which cell growth drives cell division have remained elusive. We show that cell growth during the G1 phase of the cell division cycle dilutes the cell cycle inhibitor Retinoblastoma protein (Rb) to trigger division in human cells. RB overexpression increased cell size and G1 duration, whereas RB deletion decreased cell size and removed the inverse correlation between cell size at birth and the duration of the G1 phase. Thus, Rb dilution through cell growth in G1 provides one of the long-sought molecular mechanisms that promotes cell size homeostasis.


Assuntos
Divisão Celular/fisiologia , Proteína do Retinoblastoma/fisiologia , Pontos de Checagem do Ciclo Celular/fisiologia , Proliferação de Células , Tamanho Celular , Fase G1/fisiologia , Humanos
15.
Chem Biol Interact ; 328: 109200, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32702347

RESUMO

Activation of Notch signaling is associated with tumor aggressiveness, poor clinical outcome and drug resistance in breast cancer patients. Targeting Notch signaling with small molecule inhibitors may be a better strategy for anticancer drug development. We identified 3-O-(E)-p-Coumaroylbetulinic acid (CB) as a lead compound and potent inhibitor of Notch signaling pathway. Treatment of human breast cancer MBA-MD-231 and T47D cells with CB resulted in a dose- and time-dependent inhibition of cell viability and G0/G1-phase cell cycle arrest. This effect was associated with a marked decrease in the expression of cyclin D1 and its activating partner, cyclin-dependent kinase 2 with concomitant increase in cyclin kinase inhibitor p21, operative in G1-phase of the cell cycle. CB treatment induced early apoptosis in breast cancer cells as evident by increase in cleaved caspase-3, decrease in Bcl2 and survivin, surge in reactive oxygen species and disruption of mitochondrial membrane potential. CB treatment altered Notch target genes viz. Hes1, Hey1 and E-cadherin at mRNA and protein level in time-dependent manner along with decrease in Notch promoter activity at IC50 concentration. Furthermore, CB treatment decreased mammosphere formation in MCF-7 cells through down-modulation of the Notch signaling pathway and suppression of self-renewal markers such as c-Myc, SOX-2 and CD44. Our findings demonstrate that CB possess anticancer activity in breast cancer cells and suppresses self-renewal ability in the mammosphere as a result of modulation in cell-cycle machinery, disruption of mitochondrial function, induction of apoptosis, and Notch inhibition.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Receptores Notch/antagonistas & inibidores , Receptores Notch/metabolismo , Transdução de Sinais/efeitos dos fármacos , Triterpenos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias da Mama/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Linhagem Celular Tumoral , Feminino , Células HEK293 , Humanos , Células MCF-7 , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo
16.
Nucleic Acids Res ; 48(14): 7844-7855, 2020 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-32652013

RESUMO

The catalytic activity of human AURORA-A kinase (AURKA) regulates mitotic progression, and its frequent overexpression in major forms of epithelial cancer is associated with aneuploidy and carcinogenesis. Here, we report an unexpected, kinase-independent function for AURKA in DNA replication initiation whose inhibition through a class of allosteric inhibitors opens avenues for cancer therapy. We show that genetic depletion of AURKA, or its inhibition by allosteric but not catalytic inhibitors, blocks the G1-S cell cycle transition. A catalytically inactive AURKA mutant suffices to overcome this block. We identify a multiprotein complex between AURKA and the replisome components MCM7, WDHD1 and POLD1 formed during G1, and demonstrate that allosteric but not catalytic inhibitors prevent the chromatin assembly of functional replisomes. Indeed, allosteric but not catalytic AURKA inhibitors sensitize cancer cells to inhibition of the CDC7 kinase subunit of the replication-initiating factor DDK. Thus, our findings define a mechanism essential for replisome assembly during DNA replication initiation that is vulnerable to inhibition as combination therapy in cancer.


Assuntos
Aurora Quinase A/fisiologia , Replicação do DNA , DNA Polimerase Dirigida por DNA/metabolismo , Complexos Multienzimáticos/metabolismo , Regulação Alostérica , Aurora Quinase A/antagonistas & inibidores , Aurora Quinase A/genética , Aurora Quinase A/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proteínas de Ciclo Celular/antagonistas & inibidores , Linhagem Celular , Pontos de Checagem da Fase G1 do Ciclo Celular , Células HeLa , Humanos , Interfase/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Origem de Replicação
17.
Am J Hum Genet ; 107(2): 342-351, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32673564

RESUMO

Male infertility affects ∼7% of men, but its causes remain poorly understood. The most severe form is non-obstructive azoospermia (NOA), which is, in part, caused by an arrest at meiosis. So far, only a few validated disease-associated genes have been reported. To address this gap, we performed whole-exome sequencing in 58 men with unexplained meiotic arrest and identified the same homozygous frameshift variant c.676dup (p.Trp226LeufsTer4) in M1AP, encoding meiosis 1 associated protein, in three unrelated men. This variant most likely results in a truncated protein as shown in vitro by heterologous expression of mutant M1AP. Next, we screened four large cohorts of infertile men and identified three additional individuals carrying homozygous c.676dup and three carrying combinations of this and other likely causal variants in M1AP. Moreover, a homozygous missense variant, c.1166C>T (p.Pro389Leu), segregated with infertility in five men from a consanguineous Turkish family. The common phenotype between all affected men was NOA, but occasionally spermatids and rarely a few spermatozoa in the semen were observed. A similar phenotype has been described for mice with disruption of M1ap. Collectively, these findings demonstrate that mutations in M1AP are a relatively frequent cause of autosomal recessive severe spermatogenic failure and male infertility with strong clinical validity.


Assuntos
Pontos de Checagem do Ciclo Celular/genética , Infertilidade Masculina/genética , Meiose/genética , Mutação/genética , Proteínas/genética , Espermatogênese/genética , Adulto , Alelos , Animais , Azoospermia/genética , Homozigoto , Humanos , Masculino , Camundongos , Fenótipo , Espermatozoides/anormalidades , Testículo/anormalidades , Turquia , Sequenciamento Completo do Exoma/métodos
18.
Yonsei Med J ; 61(7): 587-596, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32608202

RESUMO

PURPOSE: The current study aimed to investigate the synergistic antitumor effect of combined treatment with 17-DMAG (HSP90 inhibitor) and NVP-BEZ235 (PI3K/mTOR dual inhibitor) on cisplatin-resistant human bladder cancer cells. MATERIALS AND METHODS: Human bladder cancer cells exhibiting cisplatin resistance (T24R2) were exposed to escalating doses of 17-DMAG (2.5-20 nM) with or without NVP-BEZ236 (0.5-4 µM) in combination with cisplatin. Antitumor effects were assessed by CCK-8 analysis. Based on the dose-response study, synergistic interactions between the two regimens were evaluated using clonogenic assay and combination index values. Flow cytometry and Western blot were conducted to analyze mechanisms of synergism. RESULTS: Dose- and time-dependent antitumor effects for 17-DMAG were observed in both cisplatin-sensitive (T24) and cisplatin-resistant cells (T24R2). The antitumor effect of NVP-BEZ235, however, was found to be self-limiting. The combination of 17-DMAG and NVP-BEZ235 in a 1:200 fixed ratio showed a significant antitumor effect in cisplatin-resistant bladder cancer cells over a wide dose range, and clonogenic assay showed compatible results with synergy tests. Three-dimensional analysis revealed strong synergy between the two drugs with a synergy volume of 201.84 µM/mL²%. The combination therapy resulted in G1-phase cell cycle arrest and caspase-dependent apoptosis confirmed by the Western blot. CONCLUSION: HSP90 inhibitor monotherapy and in combination with the PI3K/mTOR survival pathway inhibitor NVP-BEZ235 shows a synergistic antitumor effect in cisplatin-resistant bladder cancers, eliciting cell cycle arrest at the G1 phase and induction of caspase-dependent apoptotic pathway.


Assuntos
Antineoplásicos/uso terapêutico , Benzoquinonas/uso terapêutico , Cisplatino/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Lactamas Macrocíclicas/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico , Serina-Treonina Quinases TOR/antagonistas & inibidores , Neoplasias da Bexiga Urinária/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica , Apoptose/efeitos dos fármacos , Benzoquinonas/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Cisplatino/farmacologia , Dano ao DNA/efeitos dos fármacos , Humanos , Imidazóis , Lactamas Macrocíclicas/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Inibidores de Proteínas Quinases/farmacologia , Quinolinas , Serina-Treonina Quinases TOR/metabolismo
19.
Anticancer Res ; 40(8): 4695-4700, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32727794

RESUMO

BACKGROUND/AIM: We investigated the anti-proliferative effect of quercetin on liver cancer cell lines. MATERIALS AND METHODS: Thirteen liver cancer cell lines were cultured followed by treatment with varying concentrations of quercetin (0-100 µM) or quercetin and 5-FU, and the cell viability was analysed by the MTT assay. Flow cytometry was also used to examine cell cycle progression after treatment with quercetin. RESULTS: The addition of quercetin resulted in a dose- and time-dependent suppression of cell proliferation. In some cell lines, treatment with quercetin and 5-FU caused an additional or synergistic effect. Most cell lines displayed cell cycle arrest at different phases of the cell cycle. CONCLUSION: Quercetin inhibits the proliferation of liver cancer cells via induction of apoptosis and cell cycle arrest.


Assuntos
Neoplasias Hepáticas/tratamento farmacológico , Quercetina/farmacologia , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Neoplasias Hepáticas/patologia
20.
Nat Chem Biol ; 16(7): 716-724, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32572259

RESUMO

Largely non-overlapping sets of cyclin-dependent kinases (CDKs) regulate cell division and RNA polymerase II (Pol II)-dependent transcription. Here we review the molecular mechanisms by which specific CDKs are thought to act at discrete steps in the transcription cycle and describe the recent emergence of transcriptional CDKs as promising drug targets in cancer. We emphasize recent advances in understanding the transcriptional CDK network that were facilitated by development and deployment of small-molecule inhibitors with increased selectivity for individual CDKs. Unexpectedly, several of these compounds have also shown selectivity in killing cancer cells, despite the seemingly universal involvement of their target CDKs during transcription in all cells. Finally, we describe remaining and emerging challenges in defining functions of individual CDKs in transcription and co-transcriptional processes and in leveraging CDK inhibition for therapeutic purposes.


Assuntos
Antineoplásicos/farmacologia , Quinases Ciclina-Dependentes/antagonistas & inibidores , Regulação Neoplásica da Expressão Gênica , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , RNA Polimerase II/genética , Bibliotecas de Moléculas Pequenas/farmacologia , Animais , Antineoplásicos/química , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/genética , Quinases Ciclina-Dependentes/genética , Quinases Ciclina-Dependentes/metabolismo , Modelos Animais de Doenças , Humanos , Neoplasias/enzimologia , Neoplasias/genética , Neoplasias/patologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteínas Quinases/química , Proteólise , RNA Polimerase II/antagonistas & inibidores , RNA Polimerase II/metabolismo , Transdução de Sinais , Bibliotecas de Moléculas Pequenas/química , Transcrição Genética
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