Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.346
Filtrar
1.
Invest Ophthalmol Vis Sci ; 60(14): 4784-4791, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31743935

RESUMO

Purpose: To investigate the antifibrotic effects of sakuraso-saponin on a primary culture of human pterygium fibroblasts (HPFs) and normal human Tenon fibroblasts (HTFs) as compared to the effects of mitomycin C (MMC). Methods: Samples of HPFs and HTFs were acquired during primary pterygium surgery. Cell toxicity, cell migration, and expression of α-smooth muscle actin (α-SMA) and transforming growth factor-ß (TGF-ß) were evaluated in HPFs and HTFs after treatment with sakuraso-saponin and MMC. To determine the possible mechanisms underlying the antifibrotic effects of sakuraso-saponin, the expression of phosphorylated Smad2/3 was evaluated after treatment with sakuraso-saponin and MMC. Results: MMC (≥200 µg/mL) significantly reduced cell viability in both HPFs and HTFs, whereas sakuraso-saponin (1.0 µg/mL) decreased cell viability in HPFs only. Both sakuraso-saponin (1.0 µg/mL) and MMC (200 µg/mL) treatment significantly reduced the expression of α-SMA and TGF-ß in HPFs (P < 0.05). It is interesting that the expression of α-SMA and TGF-ß after treatment with sakuraso-saponin was significantly lower than that after treatment with MMC (P < 0.05). The expression of phosphorylated Smad2/3 protein was decreased by sakuraso-saponin and MMC in HPFs. Both sakuraso-saponin and MMC inhibited TGF-ß1-induced cell migration as compared to the control in HPFs. Conclusions: Sakuraso-saponin could be more effective than MMC for the reduction of fibrosis in HPFs. Our results might present the basis for its use as a promising candidate drug for adjuvant therapy to prevent recurrent pterygium after surgery.


Assuntos
Alquilantes/farmacologia , Fibroblastos/efeitos dos fármacos , Mitomicina/farmacologia , Pterígio/tratamento farmacológico , Pterígio/patologia , Saponinas/farmacologia , Actinas/metabolismo , Western Blotting , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Fibroblastos/metabolismo , Fibrose/tratamento farmacológico , Humanos , Fosforilação , Pterígio/cirurgia , Proteína Smad2/metabolismo , Proteína Smad4/metabolismo , Cápsula de Tenon/citologia , Fator de Crescimento Transformador beta/metabolismo
2.
Chem Commun (Camb) ; 55(87): 13140-13143, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31617528

RESUMO

In this work, we depleted glutathione (GSH) by releasing SO2 with internal stimulus GSH itself, and also selectively marked the cancer cells followed by release of anticancer drug using another orthogonal stimulus i.e., two-photon (TP) NIR light by a single naphthalene based chromophore (TP absorbance 77 GM and uncaging cross-section 21 GM). We demonstrated the improved therapeutic efficacy of chlorambucil by the stepwise dual stimuli approach and dual surveillance of both the drug uncaging process in real-time using in vitro studies.


Assuntos
Alquilantes/farmacologia , Antineoplásicos Alquilantes/farmacologia , Clorambucila/farmacologia , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Naftalenos/farmacologia , Fótons , Alquilantes/química , Antineoplásicos Alquilantes/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Clorambucila/química , Liberação Controlada de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Glutationa/metabolismo , Humanos , Raios Infravermelhos , Estrutura Molecular , Naftalenos/química , Imagem Óptica , Dióxido de Enxofre/metabolismo
3.
Nat Commun ; 10(1): 3694, 2019 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-31455775

RESUMO

The maintenance of genetic integrity is critical for stem cells to ensure homeostasis and regeneration. Little is known about how adult stem cells respond to irreversible DNA damage, resulting in loss of regeneration in humans. Here, we establish a permanent regeneration loss model using cycling human hair follicles treated with alkylating agents: busulfan followed by cyclophosphamide. We uncover the underlying mechanisms by which hair follicle stem cells (HFSCs) lose their pool. In contrast to immediate destructive changes in rapidly proliferating hair matrix cells, quiescent HFSCs show unexpected massive proliferation after busulfan and then undergo large-scale apoptosis following cyclophosphamide. HFSC proliferation is activated through PI3K/Akt pathway, and depletion is driven by p53/p38-induced cell death. RNA-seq analysis shows that HFSCs experience mitotic catastrophe with G2/M checkpoint activation. Our findings indicate that priming mobilization causes stem cells to lose their resistance to DNA damage, resulting in permanent loss of regeneration after alkylating chemotherapy.


Assuntos
Alquilantes/farmacologia , Bussulfano/farmacologia , Ciclofosfamida/farmacologia , Folículo Piloso/citologia , Regeneração/efeitos dos fármacos , Células-Tronco/efeitos dos fármacos , Adulto , Animais , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/genética , Feminino , Folículo Piloso/transplante , Xenoenxertos , Humanos , Camundongos , Camundongos SCID , Pessoa de Meia-Idade , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células-Tronco/citologia , Transplante Heterólogo , Proteína Supressora de Tumor p53/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
4.
Nucleic Acids Res ; 47(13): 6578-6589, 2019 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-31188442

RESUMO

Higher-ordered structure motifs of nucleic acids, such as the G-quadruplex (G-4), mismatched and bulge structures, are significant research targets because these structures are involved in genetic control and diseases. Selective alkylation of these higher-order structures is challenging due to the chemical instability of the alkylating agent and side-reactions with the single- or double-strand DNA and RNA. We now report the reactive OFF-ON type alkylating agents, vinyl-quinazolinone (VQ) precursors with a sulfoxide, thiophenyl or thiomethyl group for the OFF-ON control of the vinyl reactivity. The stable VQ precursors conjugated with aminoacridine, which bind to the G-4 DNA, selectively reacted with a T base on the G-4 DNA in contrast to the single- and double-strand DNA. Additionally, the VQ precursor reacted with the T or U base in the AP-site, G-4 RNA and T-T mismatch structures. These VQ precursors would be a new candidate for the T or U specific alkylation in the higher-ordered structures of nucleic acids.


Assuntos
Alquilantes/farmacologia , DNA/efeitos dos fármacos , Conformação de Ácido Nucleico/efeitos dos fármacos , Alquilantes/síntese química , Alquilantes/química , Alquilação , Pareamento de Bases , DNA/química , DNA de Cadeia Simples/química , DNA de Cadeia Simples/efeitos dos fármacos , Quadruplex G/efeitos dos fármacos , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Purinas/química , Purinas/farmacologia , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Relação Estrutura-Atividade , Triazinas/química , Triazinas/farmacologia , Compostos de Vinila/química , Compostos de Vinila/farmacologia
5.
Braz J Biol ; 79(4): 629-638, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31017181

RESUMO

BACKGROUND: Hepatocellular carcinoma is the most frequent primary malignancy of liver and accounts for as many as one million deaths worldwide in a year. OBJECTIVES: The aim of the present study was to evaluate the anti-cancerous efficiency of Bergenia ciliata rhizome against diethylnitrosoamine induced hepatocarcinogenesis in Balb C mice. METHODS: One percent diethylnitrosoamine was prepared by using 99 ml of normal saline NaCl (0.9 percent) solution to which was added 1 ml of concentrated diethylnitrosoamine (DEN) solution (0.01 µg/µl). Extract of Bergenia ciliata was prepared by maceration technique. Mice were classified into four groups as follows: Group 1 a control group (N=7) received saline solution (3.5 µl/mg), group 2 (N=14) received diethylnitrosoamine (3.5 µl/mg) intraperitoneally once in a week for eight consecutive weeks, group 3 (N=7) received plant extract (150 mg/kg (Body weight)) once in a week, while group 4 (N=7) was given combination of diethylnitrosoamine (3.5 µl/mg) and plant extract (150 mg/kg (Body weight)). After eight weeks of DEN induction group 2 mice were divided into two subgroups containing seven mice each, subgroup 1 was sacrificed while subgroup 2 was treated with plant extract (150 mg/kg (Body weight)) once in a week for eight consecutive weeks. RESULTS: The model of DEN injected hepatocellular carcinomic (HCC) mice elicited significant decline in levels of albumin with concomitant significant elevations in tumor markers aspartate aminotransferase, alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alpha feto protein (AFP), gamma glutamyl transferase (Y-GT), 5 nucleotidase (5NT), glucose-6-phosphate dehydrogenase (G6PDH) and bilirubin. The intraperitoneal administration of B. ciliata as a protective agent, produced significant increase in albumin levels with significant decrease in the levels of tumor markers aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alpha feto protein (AFP), gamma glutamyl transferase (Y-GT), 5 nucleotidase (5NT), glucose-6-phosphate dehydrogenase (G6PDH) and bilirubin. CONCLUSION: Bergenia ciliata has potent antioxidant activity, radical scavenging capacity and anticancerous properties. Bergenia ciliata extracts may provide a basis for development of anti-cancerous drug.


Assuntos
Carcinoma Hepatocelular , Dietilnitrosamina/farmacologia , Neoplasias Hepáticas , Neoplasias Experimentais/induzido quimicamente , Extratos Vegetais/farmacologia , Saxifragaceae , Alquilantes/farmacologia , Animais , Carcinoma Hepatocelular/induzido quimicamente , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/induzido quimicamente , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C
6.
Methods Mol Biol ; 1977: 83-97, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30980324

RESUMO

Reduction and alkylation are common processing steps in sample preparation for qualitative and quantitative proteomic analyses. In principle, these steps mitigate the limitations resulting from the presence of disulfide bridges. There has been recurring debate in the proteomics community around their use, with concern over negative impacts that result from overalkylation (off-target, non-thiol sites) or incomplete reduction and/or S-alkylation of cysteine. This chapter integrates findings from a number of studies on different reduction and alkylation strategies, to guide users in experimental design for their optimal use in proteomic workflows.


Assuntos
Cisteína/metabolismo , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Proteômica , Alquilantes/farmacologia , Alquilação/efeitos dos fármacos , Oxirredução/efeitos dos fármacos , Proteômica/métodos , Substâncias Redutoras/farmacologia , Fluxo de Trabalho
7.
Sci Transl Med ; 11(483)2019 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-30867324

RESUMO

Enthusiasm for the use of antibody-drug conjugates (ADCs) in cancer therapy has risen over the past few years. The success of this therapeutic approach relies on the identification of cell surface antigens that are widely and selectively expressed on tumor cells. Studies have shown that native ALK protein is expressed on the surface of most neuroblastoma cells, providing an opportunity for development of immune-targeting strategies. Clinically relevant antibodies for this target have not yet been developed. Here, we describe the development of an ALK-ADC, CDX-0125-TEI, which selectively targets both wild-type and mutated ALK-expressing neuroblastomas. CDX-0125-TEI exhibited efficient antigen binding and internalization, and cytotoxicity at picomolar concentrations in cells with different expression of ALK on the cell surface. In vivo studies showed that CDX-0125-TEI is effective against ALK wild-type and mutant patient-derived xenograft models. These data demonstrate that ALK is a bona fide immunotherapeutic target and provide a rationale for clinical development of an ALK-ADC approach for neuroblastomas and other ALK-expressing childhood cancers such as rhabdomyosarcomas.


Assuntos
Quinase do Linfoma Anaplásico/metabolismo , Imunoconjugados/uso terapêutico , Neuroblastoma/tratamento farmacológico , Alquilantes/farmacologia , Animais , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais/uso terapêutico , Apoptose/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , DNA/metabolismo , Dano ao DNA , Modelos Animais de Doenças , Endocitose/efeitos dos fármacos , Imunoconjugados/farmacologia , Neuroblastoma/patologia , Resultado do Tratamento , Ensaios Antitumorais Modelo de Xenoenxerto
8.
Artigo em Inglês | MEDLINE | ID: mdl-30857727

RESUMO

DNA damage is ubiquitous and can arise from endogenous or exogenous sources. DNA-damaging alkylating agents are present in environmental toxicants as well as in cancer chemotherapy drugs and are a constant threat, which can lead to mutations or cell death. All organisms have multiple DNA repair and DNA damage tolerance pathways to resist the potentially negative effects of exposure to alkylating agents. In bacteria, many of the genes in these pathways are regulated as part of the SOS reponse or the adaptive response. In this work, we probed the cellular responses to the alkylating agents chloroacetaldehyde (CAA), which is a metabolite of 1,2-dichloroethane used to produce polyvinyl chloride, and styrene oxide (SO), a major metabolite of styrene used in the production of polystyrene and other polymers. Vinyl chloride and styrene are produced on an industrial scale of billions of kilograms annually and thus have a high potential for environmental exposure. To identify stress response genes in E. coli that are responsible for tolerance to the reactive metabolites CAA and SO, we used libraries of transcriptional reporters and gene deletion strains. In response to both alkylating agents, genes associated with several different stress pathways were upregulated, including protein, membrane, and oxidative stress, as well as DNA damage. E. coli strains lacking genes involved in base excision repair and nucleotide excision repair were sensitive to SO, whereas strains lacking recA and the SOS gene ybfE were sensitive to both alkylating agents tested. This work indicates the varied systems involved in cellular responses to alkylating agents, and highlights the specific DNA repair genes involved in the responses.


Assuntos
Acetaldeído/análogos & derivados , Alquilantes/farmacologia , Dano ao DNA/efeitos dos fármacos , Compostos de Epóxi/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , /genética , Acetaldeído/farmacologia , DNA Bacteriano/genética , Esterases/genética , Recombinases Rec A/genética
9.
Life Sci Alliance ; 2(1)2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30760556

RESUMO

During platelet biogenesis, microtubules (MTs) are arranged into submembranous structures (the marginal band) that encircle the cell in a single plane. This unique MT array has no equivalent in any other mammalian cell, and the mechanisms responsible for this particular mode of assembly are not fully understood. One possibility is that platelet MTs are composed of a particular set of tubulin isotypes that carry specific posttranslational modifications. Although ß1-tubulin is known to be essential, no equivalent roles of α-tubulin isotypes in platelet formation or function have so far been reported. Here, we identify α4A-tubulin as a predominant α-tubulin isotype in platelets. Similar to ß1-tubulin, α4A-tubulin expression is up-regulated during the late stages of megakaryocyte differentiation. Missense mutations in the α4A-tubulin gene cause macrothrombocytopenia in mice and humans. Defects in α4A-tubulin lead to changes in tubulin tyrosination status of the platelet tubulin pool. Ultrastructural defects include reduced numbers and misarranged MT coils in the platelet marginal band. We further observed defects in megakaryocyte maturation and proplatelet formation in Tuba4a-mutant mice. We have, thus, discovered an α-tubulin isotype with specific and essential roles in platelet biogenesis.


Assuntos
Plaquetas/fisiologia , Trombocitopenia/genética , Trombopoese/fisiologia , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismo , Alquilantes/administração & dosagem , Alquilantes/farmacologia , Animais , Antígenos CD34/metabolismo , Células Cultivadas , Etilnitrosoureia/administração & dosagem , Etilnitrosoureia/farmacologia , Humanos , Masculino , Megacariócitos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Microtúbulos/metabolismo , Mutação de Sentido Incorreto , Contagem de Plaquetas , Doadores de Tecidos
10.
Aging (Albany NY) ; 10(11): 3104-3116, 2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30398976

RESUMO

The rapid and efficient clearance of apoptotic germ cells (GCs) by Sertoli cells (SCs) is important for spermatogenesis. High mitochondrial activity in phagocytes is critical for continued clearance of apoptotic cells. However, the underlying molecular mechanism is poorly understood. Glycogen synthase kinase-3α (GSK3α) is a protein kinase that participates in the regulation of mitochondrial activity. Immunohistochemistry evidenced the predominant presence of the Ser21 phosphorylation GSK3α (inactivation) signal in SCs. Heat shock-induced apoptosis of GCs and dephosphorylation of GSK3α in SCs is a perfect model to investigate the role of GSK3α in phagocytic action. The number of apoptotic GCs was significantly lower in GSK3α inhibitor pre-treated mice with HS compared to normal control. In vitro phagocytosis assays shown that the phagocytic activity in GSK3α activated SCs was downregulated, while GSK3α inhibitor supplementation restored this process. Moreover, GSK3α activation participates in the alteration of the mitochondrial ultrastructure and activity. In particular, GSK3α activation inhibits mitochondrial fission via phosphorylation of dynamin related protein 1 at Ser637. Changes of mitochondrial activity resulted in the accumulation of lipid droplets and the alteration of metabolism pattern in SCs. In summary, our results demonstrate that inactivation of GSK3α is required for mitochondria-mediated apoptotic GCs phagocytosis in SCs.


Assuntos
Apoptose/fisiologia , Células Germinativas/fisiologia , Quinase 3 da Glicogênio Sintase/metabolismo , Mitocôndrias/metabolismo , Fagocitose/fisiologia , Células de Sertoli/fisiologia , Alquilantes/farmacologia , Animais , Bussulfano/farmacologia , Linhagem Celular , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Quinase 3 da Glicogênio Sintase/genética , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Potencial da Membrana Mitocondrial/fisiologia , Camundongos , Camundongos Endogâmicos BALB C
11.
Biomacromolecules ; 19(12): 4629-4640, 2018 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-30359516

RESUMO

There is growing interest in synthetic polymers which co-opt the structural features of naturally occurring antimicrobial peptides. However, our understanding of how macromolecular architecture affects antibacterial activity remains limited. To address this, we investigated whether varying architectures of a series of block and statistical co-oligomers influenced antibacterial and hemolytic activity. Cu(0)-mediated polymerization was used to synthesize oligomers constituting 2-(Boc-amino)ethyl acrylate units and either diethylene glycol ethyl ether acrylate (DEGEEA) or poly(ethylene glycol) methyl ether acrylate units with varying macromolecular architecture; subsequent deprotection produced primary amine functional oligomers. Further guanylation provided an additional series of antimicrobial candidates. Both chemical composition and macromolecular architecture were shown to affect antimicrobial activity. A broad spectrum antibacterial oligomer (containing guanidine moieties and DEGEEA units) was identified that possessed promising activity (MIC = 2 µg mL-1) toward both Gram-negative and Gram-positive bacteria. Bacterial membrane permeabilization was identified as an important contributor to the mechanism of action.


Assuntos
Alquilantes/química , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Estrutura Molecular , Acrilatos/química , Acrilatos/farmacologia , Alquilantes/farmacologia , Alquilação , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Cátions/química , Cátions/farmacologia , Substâncias Macromoleculares/química , Substâncias Macromoleculares/farmacologia , Testes de Sensibilidade Microbiana , Polimerização/efeitos dos fármacos , Polímeros/química , Relação Estrutura-Atividade
12.
Exp Hematol ; 67: 49-59.e1, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30102945

RESUMO

The combination of the DNA-alkylating agents busulfan (Bu) and cyclophosphamide is the most commonly used myeloablative pretransplantation conditioning therapy for myeloid leukemias. However, it is associated with significant nonrelapse mortality, which prohibits dose escalation to control relapse. We hypothesized that combining these two drugs with an epigenetic modifier would increase antileukemic efficacy without jeopardizing patient safety. A preclinical study was performed to determine the synergistic cytotoxicity of Bu, 4-hydroperoxycyclophosphamide (4HC), and the hypomethylating agent decitabine (DAC) in human acute myeloid leukemia (AML) cell lines. Exposure of KBM3/Bu2506 (P53-null) and OCI-AML3 (P53-wild-type) cells to Bu+4HC inhibited cell proliferation by ∼35-39%; addition of DAC increased the inhibition to ∼60-62%. The observed synergistic interactions correlated with DNA damage response activation, increased the production of reactive oxygen species, and decreased mitochondrial membrane potential, release of mitochondrial proapoptotic proteins into the cytoplasm, and induction of caspase-dependent programmed cell death. The Bu+4HC+DAC combination further caused chromatin trapping of DNMT1 with a concomitant increase in DNA damage. In contrast, FMS-like tyrosine kinase 3 internal tandem duplications (FLT3-ITD)-positive AML cell lines were not sensitized to Bu+4HC by inclusion of DAC; addition of the FLT3 kinase inhibitor sorafenib sensitized the FLT3-ITD-positive MV4-11 and MOLM13 cell lines to the triple drug combination by inhibiting the FLT3 signal transduction pathway. Our results therefore provide a rationale for the development of personalized conditioning therapy for patients with P53-mutated and FLT3-ITD-positive AML.


Assuntos
Alquilantes/farmacologia , Bussulfano/farmacologia , Ciclofosfamida/análogos & derivados , Metilação de DNA/efeitos dos fármacos , Leucemia Mieloide Aguda/patologia , Condicionamento Pré-Transplante , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Cromatina/metabolismo , Ciclofosfamida/farmacologia , DNA (Citosina-5-)-Metiltransferase 1/metabolismo , Dano ao DNA , Decitabina/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Sinergismo Farmacológico , Duplicação Gênica , Genes p53 , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/genética , Estresse Oxidativo/efeitos dos fármacos , Medicina de Precisão , Transdução de Sinais/efeitos dos fármacos , Sorafenibe/farmacologia , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Tirosina Quinase 3 Semelhante a fms/genética
13.
Biomed Microdevices ; 20(3): 57, 2018 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-29974243

RESUMO

Inhibition of DNA damage response pathway in combination with DNA alkylating agents may enhance the selective killing of cancer cells leading to better therapeutic effects. MDM2 binding protein (MTBP) in human has a role in G1 phase (interphase of cell cycle) and its overexpression leads to breast and ovarian cancers. Sld7 is an uncharacterized protein in budding yeast and a potential functional homologue of MTBP. To investigate the role of Sld7 as a therapeutic target, the behavior of the wild-type cells and sld7∆ mutants were monitored in 0.5 nL microbioreactors. The brightfield microscopy images were used to analyze the change in the cell size and to determine the durations of G1 and S/G2/M phases of wild type cells and mutants. With the administration of the alkylating agent, the cell size decreased and the duration of cell cycle increased. The replacement of the medium with the fresh one enabled the cells to repair their DNA. The application of calorie restriction together with DNA alkylating agent to mutant cells resulted in smaller cell size and longer G1 phase compared to those in control environment. For therapeutic purposes, the potential of MTBP in humans or Sld7 in yeast as a drug target deserves further exploration. The fabrication simplicity, robustness and low-cost of this microfluidic bioreactor made of polystyrene allowed us to perform yeast culturing experiments and show a potential for further cell culturing studies. The device can successfully be used for therapeutic applications including the discovery of new anti-microbial, anti-inflammatory, anti-cancer drugs.


Assuntos
Ciclo Celular/efeitos dos fármacos , Dispositivos Lab-On-A-Chip , Alquilantes/farmacologia , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Divisão Celular , Linhagem Celular Tumoral , Meios de Cultura/química , Dano ao DNA/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Marcação de Genes , Humanos , Neoplasias/terapia , Poliestirenos/química , Proteínas Proto-Oncogênicas c-mdm2/genética , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
14.
Oxid Med Cell Longev ; 2018: 7820890, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29849914

RESUMO

Statins are 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, and this class of drugs has been studied as protective agents against DNA damages. Alkylating agents (AAs) are able to induce alkylation in macromolecules, causing DNA damage, as DNA methylation. Our objective was to evaluate atorvastatin (AVA) antimutagenic, cytoprotective, and antigenotoxic potentials against DNA lesions caused by AA. AVA chemopreventive ability was evaluated using antimutagenicity assays (Salmonella/microsome assay), cytotoxicity, cell cycle, and genotoxicity assays in HepG2 cells. The cells were cotreated with AVA and the AA methyl methanesulfonate (MMS) or cyclophosphamide (CPA). Our datum showed that AVA reduces the alkylation-mediated DNA damage in different in vitro experimental models. Cytoprotection of AVA at low doses (0.1-1.0 µM) was observed after 24 h of cotreatment with MMS or CPA at their LC50, causing an increase in HepG2 survival rates. After all, AVA at 10 µM and 25 µM had decreased effect in micronucleus formation in HepG2 cells and restored cell cycle alterations induced by MMS and CPA. This study supports the hypothesis that statins can be chemopreventive agents, acting as antimutagenic, antigenotoxic, and cytoprotective components, specifically against alkylating agents of DNA.


Assuntos
Atorvastatina/farmacologia , Ciclofosfamida/farmacologia , Dano ao DNA/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Metanossulfonato de Metila/farmacologia , Alquilantes/química , Alquilantes/farmacologia , Alquilação , Atorvastatina/química , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Núcleo Celular/química , Núcleo Celular/efeitos dos fármacos , Ciclofosfamida/química , Células Hep G2 , Humanos , Metanossulfonato de Metila/química , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/genética
15.
J Hepatol ; 69(3): 635-643, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29758334

RESUMO

BACKGROUND & AIMS: Dysregulation of the Keap1-Nrf2 pathway has been observed in experimental and human tumors, suggesting possible roles of the pathway in cancer development. Herein, we examined whether Nrf2 (Nfe2l2) activation occurs at early steps of rat hepatocarcinogenesis, to assess critical contributions of Nrf2 to the onset of hepatocellular carcinoma (HCC). METHODS: We used wild-type (WT) and Nrf2 knockout (Nrf2KO) rats treated with a single injection of diethylnitrosamine (DENA) followed by choline-devoid methionine-deficient (CMD) diet. This experimental model causes massive fatty liver and steatohepatitis with fibrosis and enables identification of early stages of hepatocarcinogenesis. RESULTS: We found that Nrf2 activation takes place in early preneoplastic lesions identified by the marker glutathione S-transferase placental form (GSTP). Nrf2 missense mutations, known to disrupt the Keap1-Nrf2 binding, were present in 65.7% of GSTP-positive foci. Nrf2KO rats were used to directly investigate whether Nrf2 is critical for initiation and/or clonal expansion of DENA-damaged hepatocytes. While Nrf2 genetic inactivation did not alter DENA-induced initiation, it led to increased liver injury and chronic compensatory hepatocyte regeneration when rats were fed a CMD diet. However, in spite of such a permissive environment, the livers of Nrf2KO rats did not display any preneoplastic lesion unlike those of WT rats. CONCLUSIONS: These results demonstrate that, in a model of hepatocarcinogenesis resembling human non-alcoholic fatty liver disease: i) Nrf2 is activated at early steps of the tumorigenic process and ii) Nrf2 is mandatory for the clonal expansion of initiated cells, indicating that Nrf2 is critical in the onset of HCC. LAY SUMMARY: Dysregulation of the Keap1-Nrf2 molecular pathway has been observed in human tumors. In a nutritional model of hepatocarcinogenesis, the protein Nrf2 is frequently mutated/activated at early steps of the tumorigenic process. Herein, we show that Nrf2 is mandatory for the development of preneoplastic lesions. These results suggest that Nrf2 has a critical role in the onset of hepatocellular carcinoma.


Assuntos
Carcinogênese/genética , Carcinoma Hepatocelular , Colina/farmacologia , Neoplasias Hepáticas , Metionina/farmacologia , Fator 2 Relacionado a NF-E2 , Alquilantes/farmacologia , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/prevenção & controle , Dieta/métodos , Dietilnitrosamina/farmacologia , Modelos Animais de Doenças , Inativação Gênica , Lipotrópicos/farmacologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/prevenção & controle , Fator 2 Relacionado a NF-E2/antagonistas & inibidores , Fator 2 Relacionado a NF-E2/genética , Ratos , Resultado do Tratamento
16.
Nucleic Acids Res ; 46(10): 5061-5074, 2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-29635344

RESUMO

The Set2 methyltransferase and its target, histone H3 lysine 36 (H3K36), affect chromatin architecture during the transcription and repair of DNA double-stranded breaks. Set2 also confers resistance against the alkylating agent, methyl methanesulfonate (MMS), through an unknown mechanism. Here, we show that Schizosaccharomyces pombe (S. pombe) exhibit MMS hypersensitivity when expressing a set2 mutant lacking the catalytic histone methyltransferase domain or a H3K36R mutant (reminiscent of a set2-null mutant). Set2 acts synergistically with base excision repair factors but epistatically with nucleotide excision repair (NER) factors, and determines the timely nuclear accumulation of the NER initiator, Rhp23, in response to MMS. Set2 facilitates Rhp23 recruitment to chromatin at the brc1 locus, presumably to repair alkylating damage and regulate the expression of brc1+ in response to MMS. Set2 also show epistasis with DNA damage checkpoint proteins; regulates the activation of Chk1, a DNA damage response effector kinase; and acts in a similar functional group as proteins involved in homologous recombination. Consistently, Set2 and H3K36 ensure the dynamicity of Rhp54 in DNA repair foci formation after MMS treatment. Overall, our results indicate a novel role for Set2/H3K36me in coordinating the recruitment of DNA repair machineries to timely manage alkylating damage.


Assuntos
Alquilantes/farmacologia , Reparo do DNA/genética , Histona-Lisina N-Metiltransferase/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/efeitos dos fármacos , Schizosaccharomyces/genética , Quinase 1 do Ponto de Checagem/genética , Quinase 1 do Ponto de Checagem/metabolismo , DNA Helicases/genética , DNA Helicases/metabolismo , Reparo do DNA/efeitos dos fármacos , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Epistasia Genética , Regulação Fúngica da Expressão Gênica , Histona-Lisina N-Metiltransferase/genética , Lisina/metabolismo , Metanossulfonato de Metila/farmacologia , Metilação/efeitos dos fármacos , Domínios Proteicos , Proteínas de Schizosaccharomyces pombe/genética
17.
Bioorg Med Chem Lett ; 28(8): 1342-1347, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29548574

RESUMO

HxTfA 4 is a fluorescent analog of a potent cytotoxic and antimalarial agent, TfA 3, which is currently being investigated for the development of an antimalarial vaccine, PlasProtect®. HxTfA contains a p-anisylbenzimidazole or Hx moiety, which is endowed with a blue emission upon excitation at 318 nm; thus enabling it to be used as a surrogate for probing the cellular fate of TfA using confocal microscopy, and addressing the question of nuclear localization. HxTfA exhibits similar selectivity to TfA for A-tract sequences of DNA, alkylating adenine-N3, albeit at 10-fold higher concentrations. It also possesses in vitro cytotoxicity against A549 human lung carcinoma cells and Plasmodium falciparum. Confocal microscopy studies showed for the first time that HxTfA, and by inference TfA, entered A549 cells and localized in the nucleus to exert its biological activity. At biologically relevant concentrations, HxTfA elicits DNA damage response as evidenced by a marked increase in the levels of γH2AX observed by confocal microscopy and immunoblotting studies, and ultimately induces apoptosis.


Assuntos
Antimaláricos/farmacologia , Benzimidazóis/farmacologia , Núcleo Celular/metabolismo , DNA/química , Corantes Fluorescentes/farmacologia , Indóis/farmacologia , Células A549 , Alquilantes/síntese química , Alquilantes/metabolismo , Alquilantes/farmacologia , Alquilantes/toxicidade , Antimaláricos/síntese química , Antimaláricos/metabolismo , Antimaláricos/toxicidade , Apoptose/efeitos dos fármacos , Sequência de Bases , Benzimidazóis/síntese química , Benzimidazóis/metabolismo , Benzimidazóis/toxicidade , Desenho de Drogas , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/metabolismo , Corantes Fluorescentes/toxicidade , Humanos , Indóis/síntese química , Indóis/metabolismo , Indóis/toxicidade , Plasmodium falciparum/efeitos dos fármacos
18.
J Pediatr Ophthalmol Strabismus ; 55(3): 164-170, 2018 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29384564

RESUMO

PURPOSE: To compare the effect of two exposure durations of mitomycin C in combined angle and filtering surgery for primary congenital glaucoma. METHODS: This was a prospective study conducted in the Department of Ophthalmology at Alexandria Main University Hospital, Alexandria, Egypt, on 75 eyes with primary congenital glaucoma that underwent combined trabeculotomy-trabeculectomy with intraoperative mitomycin C application for 1 minute (MMC 1) or 2 minutes (MMC 2) and were followed up for 24 months. Success rates were studied and complications noted. Success was defined by a composite primary end point of an intraocular pressure (IOP) of less than 16 mm Hg under general anesthesia, without any IOP-lowering medications and with no hypotony-related complications and/or lack of IOP-related progression of the disease as evidenced by worsening of the ocular biometric characteristics. RESULTS: The mean age of the study participants was 6.7 ± 4.1 months (range: 2 to 16 months; median: 6 months) in the MMC 1 group (35 eyes) and 7.7 ± 5.7 months (range: 1 to 32 months; median: 6.5 months) in the MMC 2 group (40 eyes). The initial surgery was successful in 32 (91.5%) and 31 (77.5%) eyes in the MMC 1 and MMC 2 groups, respectively. The mean IOP was 18.4 ± 5.1 and 18.1 ± 6.1 mm Hg preoperatively and 5.5 ± 3.5 and 4.8 ± 2.8 mm Hg at the end of follow-up in the MMC 1 and MMC 2 groups, respectively. There was no statistically significant difference in the clinical parameters between the two groups. Complications included cataracts in each group and hypotony optic disc edema in 3 eyes (7.5%) in the MMC 2 group. CONCLUSIONS: Both mitomycin C application durations were effective in combined trabeculotomy-trabeculectomy with mitomycin C for primary congenital glaucoma. The longer duration was not advantageous in disease control and there were no significant differences in complications. [J Pediatr Ophthalmol Strabismus. 2018;55(3):164-170.].


Assuntos
Cirurgia Filtrante/métodos , Glaucoma/cirurgia , Pressão Intraocular , Mitomicina/farmacologia , Idoso , Alquilantes/farmacologia , Feminino , Seguimentos , Glaucoma/congênito , Glaucoma/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Tempo , Adulto Jovem
19.
Int J Pediatr Otorhinolaryngol ; 105: 79-84, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29447825

RESUMO

OBJECTIVES: We aimed to investigate the prophylactic effect simvastatin of and mitomycin C (MMC) on laryngeal and tracheal stenosis in tracheotomised rats by histopathological evaluation of laryngotracheal segment. Randomized prospective single-blind. MATERIAL AND METHOD: Standard vertical tracheotomy was performed on 24 rats. Then the animals were randomly divided into three groups as A, B and C. In group A 0.4 mg/day once daily mitomycin C was injected to the paratracheal region for 14 days. In group B daily 30 mg/kg/day simvastatin was given via gavage to rats for 14 days. In group C 2 cc/day intraperitoneal saline given to rats and the created control group by 14 days follow up. After 10 days, tracheal cannulas were removed. Three weeks later, all animals were euthanized and trachea specimens were harvested. The present study investigates the effects of MMC and Simvastatin on fibrosis, inflammation, stenosis index and tracheal wall thickness in a tracheal injury model. RESULTS: The difference between the groups in terms of degree of inflammation scores was statistically insignificant (P = 0,187). Differences between the groups were found to be insignificant in terms of the preventionof fibrosis (P = 0,993). There was no significant difference between groups in terms of stenosis index (P = 0.645). In terms of wall thickness, control, simvastatin and mitomycin C groups were statistically different (p = 0.038). The difference between post-hoc test results was between Mitomycin C and control groups (p = 0.036). Maximum wall thickness in the MMC group (0,299 mm) was significantly lower compared to the control group (0,382 mm)(P < 0,0001). Maximum wall thickness was statistically lower in the simvastatin (0.324 mm) group compared with the control group (0.382 mm) (P < 0.0001). There was no statistically significant difference between the simvastatin group (0,198 mm) and control group (0,200 mm) with respect to minimum wall thickness (P = 0.982). Minimum wall thickness was significantly lower in the mitomycin-C group (0,160 mm) comparison to the control group (0,200 mm) (P < 0.0001). CONCLUSION: It was detected that the simvastatin and MMC is not effective in preventing the tracheal stenosis, inflammation and fibrosis formation.


Assuntos
Alquilantes/farmacologia , Anticolesterolemiantes/farmacologia , Laringoestenose/tratamento farmacológico , Mitomicina/farmacologia , Sinvastatina/farmacologia , Estenose Traqueal/tratamento farmacológico , Animais , Feminino , Fibrose/tratamento farmacológico , Inflamação/tratamento farmacológico , Laringe/patologia , Estudos Prospectivos , Ratos , Método Simples-Cego , Traqueia/patologia , Estenose Traqueal/cirurgia , Traqueotomia
20.
Mol Cancer Ther ; 17(3): 661-670, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29237807

RESUMO

Near-infrared photoimmunotherapy (NIR-PIT) is a highly selective tumor treatment that uses an antibody-photoabsorber conjugate (APC). However, the effect of NIR-PIT can be enhanced when combined with other therapies. NIR photocaging groups, based on the heptamethine cyanine scaffold, have been developed to release bioactive molecules near targets after exposure to light. Here, we investigated the combination of NIR-PIT using panitumumab-IR700 (pan-IR700) and the NIR-releasing compound, CyEt-panitumumab-duocarmycin (CyEt-Pan-Duo). Both pan-IR700 and CyEt-Pan-Duo showed specific binding to the EGFR-expressing MDAMB468 cell line in vitro In in vivo studies, additional injection of CyEt-Pan-Duo immediately after NIR light exposure resulted in high tumor accumulation and high tumor-background ratio. To evaluate the effects of combination therapy in vivo, tumor-bearing mice were separated into 4 groups: (i) control, (ii NIR-PIT, (iii) NIR-release, (iv) combination of NIR-PIT and NIR-release. Tumor growth was significantly inhibited in all treatment groups compared with the control group (P < 0.05), and significantly prolonged survival was achieved (P < 0.05 vs. control). The greatest therapeutic effect was shown with NIR-PIT and NIR-release combination therapy. In conclusion, combination therapy of NIR-PIT and NIR-release enhanced the therapeutic effects compared with either NIR-PIT or NIR-release therapy alone. Mol Cancer Ther; 17(3); 661-70. ©2017 AACR.


Assuntos
Neoplasias da Mama/terapia , Imunoconjugados/farmacologia , Raios Infravermelhos , Terapia de Alvo Molecular/métodos , Fototerapia/métodos , Ensaios Antitumorais Modelo de Xenoenxerto , Alquilantes/química , Alquilantes/farmacologia , Animais , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Terapia Combinada , Feminino , Humanos , Imunoconjugados/química , Indóis/química , Indóis/farmacologia , Camundongos Nus , Pirrolidinonas/química , Pirrolidinonas/farmacologia , Carga Tumoral
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA