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1.
Heliyon ; 10(9): e30360, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38711658

RESUMO

In amyotrophic lateral sclerosis (ALS), astrocytes are considered key players in some non-cell non-neuronal autonomous mechanisms that underlie motor neuron death. However, it is unknown how much of these deleterious features were permanently acquired. To assess this point, we evaluated if the most remarkable features of neurotoxic aberrant glial phenotypes (AbAs) isolated from paralytic rats of the ALS model G93A Cu/Zn superoxide dismutase 1 (SOD1) could remain upon long lasting cultivation. Real time PCR, immunolabelling and zymography analysis showed that upon many passages, AbAs preserved the cell proliferation capacity, mitochondrial function and response to different compounds that inhibit some key astrocyte functions but decreased the expression of parameters associated to cell lineage, homeostasis and inflammation. As these results are contrary to the sustained inflammatory status observed along disease progression in SOD1G93A rats, we propose that the most AbAs remarkable features related to homeostasis and neurotoxicity were not permanently acquired and might depend on the signaling coming from the injuring microenvironment present in the degenerating spinal cord of terminal rats.

2.
Int J Dev Neurosci ; 83(3): 274-296, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37073624

RESUMO

Ultrastructural features of striatal white matter and cells in an in vivo model of glutaric acidemia type I created by intracerebral injection of glutaric acid (GA) were analyzed by transmission electron microscopy and immunohistochemistry. To test if the white matter damage observed in this model could be prevented, we administered the synthetic chemopreventive molecule CH38 ((E)-3-(4-methylthiophenyl)-1-phenyl-2-propen-1-one) to newborn rats, previous to an intracerebroventricular injection of GA. The study was done when striatal myelination was incipient and when it was already established (at 12 and 45 days post-injection [DPI], respectively). Results obtained indicate that that the ultrastructure of astrocytes and neurons did not appear significantly affected by the GA bolus. Instead, in oligodendrocytes, the most prominent GA-dependent injury defects included endoplasmic reticulum (ER) stress and nuclear envelope swelling at 12 DPI. Altered and reduced immunoreactivities against heavy neurofilament (NF), proteolipid protein (PLP), and myelin-associated glycoprotein (MAG) together with axonal bundle fragmentation and decreased myelin were also found at both ages analyzed. CH38 by itself did not affect striatal cells or axonal packages. However, the group of rats that received CH38 before GA did not show evidence neither of ER stress nor nuclear envelope dilation in oligodendrocytes, and axonal bundles appeared less fragmented. In this group, labeling of NF and PLP was similar to the controls. These results suggest that the CH38 molecule is a candidate drug to prevent or decrease the neural damage elicited by a pathological increase of GA in the brain. Optimization of the treatments and identification of the mechanisms underlying CH38 protective effects will open new therapeutic windows to protect myelin, which is a vulnerable target of numerous nervous system diseases.


Assuntos
Chalconas , Bainha de Mielina , Ratos , Animais , Bainha de Mielina/metabolismo , Bainha de Mielina/ultraestrutura , Chalconas/metabolismo , Chalconas/farmacologia , Neurônios/metabolismo , Axônios/metabolismo , Oligodendroglia/metabolismo
3.
Br J Sociol ; 73(4): 754-785, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35851658

RESUMO

In this paper, we examine whether social class and class divides in social networks contribute to individuals' attachment to society. We argue that network segregation restricts individuals' social worlds, thereby diminishing societal attachment. Our research site is Chile, a country with relatively low social cohesion and one of the world's highest levels of economic inequality. We use large-scale representative survey data collected in 2016 for the Chilean urban population aged 18-75 years (n = 2983) and interrelate indicators of well-established dimensions and sub-dimensions of societal attachment. Results of our regression analyses show that members of the upper middle class are more attached to society than their fellow citizens from other social strata. In addition, having more social contacts within one's own social class reduces attachment to society. In particular, network homogeneity lessens societal attachment for lower- and upper-class individuals, but not so strongly in the middle class. We conclude that social cohesion in Chilean society would be enhanced not only by more equal opportunities but also by changes to the social settings in which social class segregation is (re)produced.


Assuntos
Segregação Social , Chile , Humanos , Classe Social , Inquéritos e Questionários , População Urbana
4.
Int J Qual Stud Educ ; 35(8): 891-903, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36644015

RESUMO

The initiative to investigate the themes of migration, art and culture in this research arose from our experiences after Hurricane Maria. We begin with the view that culture, in the form of art etc., is threaded through the entire post-hurricane experience, from response and resilience to recovery and resistance. We wish to consider how our research contributes to an understanding of how the migration of Puerto Ricans after the catastrophe might accelerate the process of cultural change. We do this by exploring how art and culture are used as a mechanism of resistance. Our desire to conduct research on this topic developed as a result of our firsthand experiences and reflections. First, the theme of migration, linked to cultural change, arose from our experience of seeing our close relatives such as our siblings, uncles, cousins, leave our island and see how they had to adapt to a new culture and redefine their cultural practices. Second, the theme of art, in all its facets (music, painting, drawing … ), arose from our motivation after Hurricane Maria, from our way of coping with the situation and letting our feelings come out through art, thus demonstrating a resistance to not falling into a decline in both physical and mental health and a persistence for wanting to overcome the disaster despite the situation. Puerto Rican culture is one of the most important components of our society, as it defines our identity as Puerto Ricans for many reasons such as our music, food and dancing. This allows us to share as a community. Also, we recognise that in Puerto Rico, awareness and acknowledgement of culture has faded to some extent; only on "Puerto Rican Day" is when our culture and traditions are noticed. This is confirmed by the responses of the respondents in our research study. This is why we decided to investigate how important culture is for Puerto Rican migrants and family and friends who remained and what it means to them.

5.
Rev. med. vet. (Bogota) ; (43): 87-95, jul.-dic. 2021. graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1376997

RESUMO

Abstract The aim of this study was to describe histologically and histochemically the pancreas of three adult Hydrochoerus isthmius, attacked by feral dog in Buenavista, Córdoba, Colombia. A complete necropsy was performed and pancreatic fragments were collected and stored in 10% buffered formalin and Bouin liquid. Then, they were dehydrated, diaphanized and embedded in paraffin, stained with Hematoxylin & Eosin, P.A.S., Gomori trichrome, Grimelius and Masson Fontana modified. The H. isthmius pancreas presented a duodenal mesenteric pattern. The exocrine portion was described as a composite tubuloacinar gland. The endocrine portion of the pancreas was constituted by pancreatic islets of Langerhans and a diffuse neuroendocrine system. The histological and histochemical techniques used allowed us to identify the exocrine and endocrine portion of the organ. It is suggested to complement this study with some special techniques for the identification of specific endocrine cells, such as Beta, Alpha, Delta, Epsilon, PP or Gamma.


Resumen El objetivo del presente estudio fue describir histológica e histoquímicamente el páncreas de tres individuos adultos de Hydrochoerus isthmius atacados por perros ferales en Buenavista, Córdoba, Colombia. Se realizó una necropsia completa y se recolectaron fragmentos pancreáticos, los cuales se almacenaron en formol tamponado al 10 % y líquido Bouin. Luego, fueron deshidratados, diafanizados y embebidos en parafina; teñidos con hematoxilina y eosina, P.A.S., tricrómico Gomori, Grimelius y Masson Fontana modificado. El páncreas de H. isthmius presentó un patrón mesentérico duodenal. La porción exocrina fue descrita como una glándula tubuloacinar compuesta. La porción endocrina del páncreas estaba constituida por islotes pancreáticos o Langerhans, y un sistema neuroendocrino difuso. En ese contexto, las técnicas histológicas e histoquímicas utilizadas permitieron identificar la porción exocrina y endocrina del órgano. Se sugiere complementar este estudio con algunas técnicas especiales para la identificación de células endocrinas específicas, como Beta, Alpha, Delta, Epsilon, PP o Gamma.

6.
Bioorg Med Chem ; 24(8): 1665-74, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-26970663

RESUMO

Cancer chemoprevention involves prevention/delay/reverse of the carcinogenic process through administration of cancer chemopreventive agents (CCA). Compounds which are able to induce detoxification-enzymes, especially monofunctional phase II enzymes, have become in excellent approaches for new CCA. Herein, we report the synthesis of new furoxanyl chalcone-like hybrid compounds as CCA. In vitro studies showed that phenylfuroxanyl derivatives 6 and 9 displayed the best activities being 9 the greatest monofunctional-inducer. Additionally, compounds were non-mutagenic against TA98 Salmonella typhimurium strain (Ames test) and could be used in the prevention of the progression of pre-malignant lesions for their cytotoxic activity against tumoral cells. In vivo proof of concept showed increment on phase II-enzymes activities in liver, colon and mammary gland having derivative 9 the best induction profiles. We probed Nrf2 nuclear translocation is operative for both compounds allowing to exert protective effects via expression of downstream phase-II enzymes.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Chalcona/farmacologia , Glutationa Transferase/metabolismo , NAD(P)H Desidrogenase (Quinona)/metabolismo , Oxidiazóis/farmacologia , Animais , Antineoplásicos/síntese química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Chalcona/síntese química , Chalcona/química , Sistema Enzimático do Citocromo P-450/metabolismo , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Indução Enzimática/efeitos dos fármacos , Feminino , Células HT29 , Humanos , Células MCF-7 , Estrutura Molecular , Oxidiazóis/síntese química , Oxidiazóis/química , Ratos , Ratos Wistar , Salmonella typhimurium/efeitos dos fármacos , Relação Estrutura-Atividade , Células Tumorais Cultivadas
7.
Comp Cytogenet ; 9(1): 31-50, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25893073

RESUMO

The horn fly, Haematobiairritans is an obligate haematophagous cosmopolitan insect pest. The first reports of attacks on livestock by Haematobiairritans in Argentina and Uruguay occurred in 1991, and since 1993 it is considered an economically important pest. Knowledge on the genetic characteristics of the horn fly increases our understanding of the phenotypes resistant to insecticides that repeatedly develop in these insects. The karyotype of Haematobiairritans, as previously described using flies from an inbred colony, shows a chromosome complement of 2n=10 without heterochromosomes (sex chromosomes). In this study, we analyze for the first time the chromosome structure and variation of four wild populations of Haematobiairritans recently established in the Southern Cone of South America, collected in Argentina and Uruguay. In these wild type populations, we confirmed and characterized the previously published "standard" karyotype of 2n=10 without sex chromosomes; however, surprisingly a supernumerary element, called B-chromosome, was found in about half of mitotic preparations. The existence of statistically significant karyotypic diversity was demonstrated through the application of orcein staining, C-banding and H-banding. This study represents the first discovery and characterization of horn fly karyotypes with 2n=11 (2n=10+B). All spermatocytes analyzed showed 5 chromosome bivalents, and therefore, 2n=10 without an extra chromosome. Study of mitotic divisions showed that some chromosomal rearrangements affecting karyotype structure are maintained as polymorphisms, and multiple correspondence analyses demonstrated that genetic variation was not associated with geographic distribution. Because it was never observed during male meiosis, we hypothesize that B-chromosome is preferentially transmitted by females and that it might be related to sex determination.

8.
Rev. med. vet. (Bogota) ; (28): 43-55, dic. 2014.
Artigo em Espanhol | LILACS-Express | LILACS | ID: lil-730990

RESUMO

Se recolectaron 69 muestras de Trachemys callirostris en condiciones ex situ e in situ, para determinar sus parámetros hematológicos, comparar estos valores (considerando sexo, edad y condición) y establecer la morfología de sus células. A los animales se les extrajo sangre de la vena yugular. Se determinaron hematocrito, concentración de hemoglobina, recuentos total de eritrocitos, leucocitos y trombocitos e índices eritrocitarios (volumen corpuscular medio, hemoglobina corpuscular media y concentración de hemoglobina corpuscular media). En extendidos sanguíneos se realizaron el conteo diferencial de leucocitos y la descripción de la morfología de las células encontradas. Los valores promedio encontrados para todos los individuos fueron: hematocrito (29,9% ± 5,1), hemoglobina (4,0 ± 1,0 g/dl), VCM (327 ± 15,3 fl), HCM (45 ± 17,5 pg), CMHC (14 ± 6%), conteo total de trombocitos (15,0 ± 5,4 X 10³ µL), conteo total de eritrocitos (0,92 x 10(6)/µL ± 0,12), conteo total de leucocitos (12,10 ± 5,0 x 10³ µL). Al aplicar el análisis de varianza se encontró que no existe diferencia estadísticamente significativa (p < 0,05) entre Trachemys callirostris de distintos pesos (500 a 2000 g). Sin embargo, existen diferencias significativas (p < 0,05) y altamente significativas (p < 0,01) de la mayoría de las variables hematológicas entre sexos y entre hicoteas mantenidas en condición in situ y ex situ. De esta forma, las diferencias encontradas entre individuos, dependiendo su peso, sexo y condición de mantenimiento (in situ o ex situ), sirven como referencia para el establecimiento de protocolos de manejo de la especie en cautiverio.


69 samples from Trachemys callirostris were collected in situ and ex situ, to determine their hematological parameters, to compare these values (considering sex, age, and condition), and to establish the morphology of their cells. Blood was collected from the jugular vein of the animals. Hematocrit, hemoglobin concentration, total counts of erythrocytes, leukocytes and thrombocytes, and red cell indices were determined (mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration). Differential leukocyte count was performed, and the morphology of cells found in blood smears was described. The average values found for all individuals were: hematocrit (29.9% ± 5.1), hemoglobin (4.0 ± 1.0 g / dl), MCV (327 ± 15.3 fL), MCH (45 ± 17.5 pg), MCHC (14 ± 6%), total count of thrombocytes (15.0 ± 5.4 x 10³ µL), total count of erythrocytes (0.92 x 10(6) µL ± 0.12), and total count of leukocytes (12.10 ± 5.0 x 10³ µL). Analysis of variance showed no statistically significant difference (p < 0.05) between Trachemys callirostris of different weights (500 to 2000 g). Nevertheless, it showed significant (p <0.05) and highly significant differences (p <0.01) for most hematologic variables between sexes and hicotea turtles maintained in situ and ex situ. Thus, differences found between individuals, depending on weight, sex and condition of maintenance (in situ or ex situ), serve as a reference to establish protocols for maintaining turtles in captivity.


Coletaram-se 69 amostras de Trachemys callirostris em condições ex situ e in situ, para determinar seus parâmetros hematológicos, comparar estes valores (considerando sexo, idade e condição) e estabelecer a morfologia de suas células. Aos animais lhes foi extraído sangue da veia jugular. Determinara-se hematócrito, concentração de hemoglobina, recontagens total de eritrócitos, leucócitos e trombócitos e índices eritrocitários (volume corpuscular médio, hemoglobina corpuscular média e concentração de hemoglobina corpuscular média). No sangue estendido foi realizada a contagem diferencial de leucócitos e a descrição da morfologia das células encontradas. Os valores médios encontrados para todos os indivíduos foram: hematócrito (29,9% ± 5,1), hemoglobina (4,0 ± 1,0 g/dl), VCM (327 ± 15,3 fl), HCM (45 ± 17,5 pg), CMHC (14 ± 6%), contagem total de trombócitos (15,0 ± 5,4 x 10³ µL), contagem total de eritrocitos (0,92 x 10(6) µL ± 0,12), contagem total de leucócitos (12,10 ± 5,0 x 10³ µL). Ao aplicar a análise de variância se encontrou que não existe diferença estatisticamente significativa (p < 0,05) entre Trachemys callirostris de diferentes pesos (500 a 2000 g). Porém, existem diferenças significativas (p < 0,05) e altamente significativas (p < 0,01) da maioria das variáveis hematológicas entre sexos e entre hicoteas mantidas em condição in situ e ex situ. Desta forma, as diferenças encontradas entre indivíduos, dependendo seu peso, sexo e condição de manutenção (in situ ou ex situ), servem como referência para o estabelecimento de protocolos de manejo da espécie em cativeiro.

9.
Ces med. vet. zootec ; 9(1): 15-25, ene.-jun. 2014. ilus, tab
Artigo em Espanhol | LILACS | ID: lil-734962

RESUMO

Resumen Se hizo una evaluación posmortem de 41 individuos de T. callirostris, mantenidos en cautiverio durante el 2009 en el Centro de Atención de Fauna (CAV-CVS), a través de exámenes histopatológicos de los principales órganos y lesiones encontradas. Para esto se realizó un examen clínico externo de los individuos y se evaluó cada uno de los órganos macroscópicamente. Los órganos que presentaron anomalías fueron colectados para histopatología con la tinción Hematoxilina-Eosina. De los individuos evaluados, el principal hallazgo patológico externo correspondió a la enfermedad septicémica ulcerativa cutánea (SCUD), el cual se presentó en el 90% de los individuos. A la evaluación macroscópica de los órganos internos, se observaron anomalías en la cavidad celómica, hígado, bazo y pulmones. Se presentaron lesiones en el 71% de los hígados, 92% de los bazos, 41% de los riñones y 40% de los pulmones. Lo anterior demuestra el efecto negativo que tiene el cautiverio sobre los individuos silvestres de esta especie que han sido decomisados producto del tráfico ilegal.


A postmortem evaluation of 41 T. callirostris kept in captivity during the year 2009 was conducted at CAV-CVS Wildlife Care Center. The evaluation was performed in animals confiscated as a result of illegal trafficking. Histopathological examination of main organs and lesions was conducted in all animals. External clinical examination was also conducted and organs were macroscopically evaluated. Organs with anomalies were collected for histopathology and stained with hematoxylin-eosin stain. The most common external pathology found was Septicemic Cutaneous Ulcerative Disease (SCUD), present in 90% of the individuals. Abnormalities in the coelomic cavity, liver, spleen and lungs were observed while performing the macroscopic evaluation of internal organs. Lesions were present in 71% of livers, 92% of spleens, 41% of kidneys, and 40% of the lungs. This study shows the negative effects of captivity on wild individuals of this species.


Avaliou-se o estado sanitário post-mortem de 41 indivíduos de T.callirostris, mantidos em cativeiro durante o 2009 no centro de atenção de fauna Silvestre (CAV-CVS). A avaliação se fez a traves de analise histopatológica dos principais órgãos e lesões encontradas. Para isto, realizou-se uma avaliação clinica externa dos indivíduos e avaliaram-se cada um dos órgãos macroscopicamente. Os órgãos que apresentaram anomalias foram coletados para histopatologia com Hematoxilina-Eosina. Dos indivíduos avaliados, a principal descoberta no exame patológico externo correspondeu a doença septicêmica ulcerativa cutânea (SCUD), o qual apresentou-se no 90% dos indivíduos (37/41). Na avaliação macroscópica dos órgãos internos, observaram-se anomalias na cavidade celômica, fígado, baço e pulmões. Apresentaram-se lesões no 71% dos fígados, 92% dos baços, 41% dos rins e 40% dos pulmões. O anterior demonstra o efeito negativo que tem o cativeiro sob os indivíduos silvestres desta espécie que tem sido decomisados como produto do trafego ilegal.

10.
Cancer Res ; 68(13): 5216-25, 2008 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-18593922

RESUMO

Despite recent progress in its treatment, multiple myeloma (MM) remains incurable, thus necessitating identification of novel anti-MM agents. We report that the marine-derived cyclodepsipeptide Aplidin exhibits, at clinically achievable concentrations, potent in vitro activity against primary MM tumor cells and a broad spectrum of human MM cell lines, including cells resistant to conventional (e.g., dexamethasone, alkylating agents, and anthracyclines) or novel (e.g., thalidomide and bortezomib) anti-MM agents. Aplidin is active against MM cells in the presence of proliferative/antiapoptotic cytokines or bone marrow stromal cells and has additive or synergistic effects with some of the established anti-MM agents. Mechanistically, a short in vitro exposure to Aplidin induces MM cell death, which involves activation of p38 and c-jun NH(2)-terminal kinase signaling, Fas/CD95 translocation to lipid rafts, and caspase activation. The anti-MM effect of Aplidin is associated with suppression of a constellation of proliferative/antiapoptotic genes (e.g., MYC, MYBL2, BUB1, MCM2, MCM4, MCM5, and survivin) and up-regulation of several potential regulators of apoptosis (including c-JUN, TRAIL, CASP9, and Smac). Aplidin exhibited in vivo anti-MM activity in a mouse xenograft model. The profile of the anti-MM activity of Aplidin in our preclinical models provided the framework for its clinical testing in MM, which has already provided favorable preliminary results.


Assuntos
Depsipeptídeos/farmacologia , Depsipeptídeos/uso terapêutico , Mieloma Múltiplo/tratamento farmacológico , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/fisiologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Técnicas de Cocultura , Depsipeptídeos/administração & dosagem , Depsipeptídeos/isolamento & purificação , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Fator de Crescimento Insulin-Like I/farmacologia , Interleucina-6/farmacologia , Camundongos , Camundongos SCID , Mieloma Múltiplo/genética , Mieloma Múltiplo/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Peptídeos Cíclicos , Água do Mar , Células Estromais/efeitos dos fármacos , Células Estromais/fisiologia , Fatores de Tempo , Resultado do Tratamento , Urocordados/química , Ensaios Antitumorais Modelo de Xenoenxerto
11.
Chem Biol ; 12(11): 1201-10, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16298299

RESUMO

We have analyzed the DNA binding properties of the antitumor agent trabectedin (ET-743, Yondelis) and different analogs, namely, ET-745, lacking the C21-hydroxyl group, and ET-637, ET-594, ET-637-OBu, with modifications at the trabectedin C domain, versus their effects on cell cycle, apoptosis, and gene expression. ET-745 failed to bind DNA, highlighting the importance of the C21-hydroxyl group for DNA binding. Analogs ranked trabectedin >> ET-637 approximately ET-594 > ET-637-OBu >> ET-745 for their DNA binding capacity; ET-637 and ET-594 display very different biological activities. Drugs were clustered in three major groups showing high (trabectedin, ET-637), intermediate (ET-637-OBu), and low (ET-594, ET-745) cytotoxic activity and similar transcriptional profiling responses. C21-hydroxyl-deficient analogs of the above-mentioned compounds showed a dramatic decrease in biological activity. Our data suggest that trabectedin interacts with an additional non-DNA target to raise an effective antitumor response, and that this interaction is favored through trabectedin-DNA complexes.


Assuntos
Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , DNA/metabolismo , Dioxóis/metabolismo , Dioxóis/farmacologia , Isoquinolinas/metabolismo , Isoquinolinas/farmacologia , Antineoplásicos/química , Sequência de Bases , Caspase 3 , Caspases/metabolismo , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , DNA/química , DNA/genética , Dioxóis/química , Ativação Enzimática/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Humanos , Isoquinolinas/química , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Estrutura Molecular , Desnaturação de Ácido Nucleico/efeitos dos fármacos , Especificidade por Substrato , Temperatura , Tetra-Hidroisoquinolinas , Trabectedina
12.
Cancer Lett ; 221(2): 165-75, 2005 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-15808402

RESUMO

Lamellarin D (LAM-D) is a marine alkaloid endowed with potent cytotoxic activities against various tumor cells, in particular human prostate cancer cells and leukemia cells. Its cytotoxic action is dependent, at least in part, to its capacity to inhibit topoisomerase I. P388CPT5 murine leukemia cells resistant to the reference topoisomerase I poison camptothecin (CPT) are cross-resistant to LAM-D but the relative resistance index (RRI) is significantly reduced with LAM-D (RRI=21) compared to CPT (RRI=103). To comprehend further the mechanism of action of this novel marine antitumor agent, we have investigated the influence of the P glycoprotein (Pgp) on the cytotoxicity of LAM-D and the proapoptotic effects induced by the alkaloid. P388CPT5 cells, expressing a mutated top1 gene, display a functional Pgp, as judged from cytometry experiments performed with cells treated with rhodamine 123 or calcein-ester whereas no Pgp activity was detected with the parental P388 cells. P388CPT5 cells are also cross-resistant to the topoisomerase II poisons doxorubicin and etoposide but the resistance is abolished in the presence of verapamil or quinine (at non toxic concentrations) which reverse the multidrug resistance (MDR) phenotype. In contrast, the RRI measured with LAM-D and CPT remain unchanged in the presence of the two MDR reversal agents. The effects of LAM-D on the cell cycle progression were different in the parental P388 cells compared with the CPT-resistant which were blocked in the S and subsequently G2-M phases of the cell cycle. Cytometry experiments with the JC-1 fluorescent marker revealed that LAM-D and CPT promoted apoptosis in parental P388 cells via an activation of the mitochondrial pathway. In contrast, a massive depolarisation of the mitochondrial membrane potential and a nuclear fragmentation were detected only with LAM-D on P388CPT5 cells. This in vitro work identifies LAM-D as a potent pro-apoptotic agent and its cytotoxic action is fully maintained in multidrug-resistant cells compared to the sensitive parental cell line.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Cumarínicos/farmacologia , Resistencia a Medicamentos Antineoplásicos , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Isoquinolinas/farmacologia , Inibidores da Topoisomerase I , Animais , Antibióticos Antineoplásicos/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , DNA Topoisomerases Tipo I/genética , DNA Topoisomerases Tipo I/metabolismo , DNA Topoisomerases Tipo II/genética , DNA Topoisomerases Tipo II/metabolismo , Doxorrubicina/farmacologia , Resistência a Múltiplos Medicamentos , Etoposídeo/farmacologia , Fluoresceínas/metabolismo , Leucemia P388/tratamento farmacológico , Leucemia P388/enzimologia , Potenciais da Membrana/efeitos dos fármacos , Camundongos , Mitocôndrias/efeitos dos fármacos , Rodamina 123/metabolismo , Inibidores da Topoisomerase II , Verapamil/farmacologia
13.
J Biol Chem ; 277(4): 3047-52, 2002 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-11714725

RESUMO

Human Elongator complex was purified to virtual homogeneity from HeLa cell extracts. The purified factor can exist in two forms: a six-subunit complex, holo-Elongator, which has histone acetyltransferase activity directed against histone H3 and H4, and a three-subunit core form, which does not have histone acetyltransferase activity despite containing the catalytic Elp3 subunit. Elongator is a component of early elongation complexes formed in HeLa nuclear extracts and can interact directly with RNA polymerase II in solution. Several human homologues of the yeast Elongator subunits were identified as subunits of the human Elongator complex, including StIP1 (STAT-interacting protein 1) and IKAP (IKK complex-associated protein). Mutations in IKAP can result in the severe human disorder familial dysautonomia, raising the possibility that this disease might be due to compromised Elongator function and therefore could be a transcription disorder.


Assuntos
Acetiltransferases/química , Acetiltransferases/isolamento & purificação , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas de Saccharomyces cerevisiae , Acetiltransferases/metabolismo , Sequência de Aminoácidos , Animais , Western Blotting , Proteínas de Transporte/química , Linhagem Celular , Núcleo Celular/metabolismo , Clonagem Molecular , Disautonomia Familiar/genética , Disautonomia Familiar/metabolismo , Células HeLa , Histona Acetiltransferases , Histonas/química , Humanos , Insetos , Dados de Sequência Molecular , Mutação , Ligação Proteica , Estrutura Terciária de Proteína , RNA Polimerase II/metabolismo , Homologia de Sequência de Aminoácidos , Transcrição Gênica , Fatores de Elongação da Transcrição
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