RESUMO
Despite the lack of a complete understanding of the disparities involved, prostate cancer (PCa) has both higher incidence and death rates in African American Men (AAM) relative to those of Caucasian American Men (CAM). MHC class I polypeptide related sequence A (MICA) is an innate immunity protein involved in tumor immunoevasion. Due to a lack of reports of race-specific expression of MICA in PCa, we evaluated MICA expression in patients' tumors and in cell lines from a racially diverse origin. Immunohistochemistry was done on a tissue microarray (TMA) with antibodies against MICA. Tumor MICA mRNA was assessed by data mining using Oncomine and PROGeneV2. Surface MICA and release rate of soluble (s) MICA was evaluated in PCa cell lines originally derived from African American (MDA-PCa-2b) or Caucasian (LNCaP and DU-145) PCa patients. Prostate tumor tissue had a 1.7-fold higher MICA expression relative to normal tissue (pâ¯<â¯.0001). MICA immunoreactivity in PCa tissue from AAM was 24% lower (pâ¯=â¯.002) compared to CAM. Survival analysis revealed a marginal association of low MICA with poor overall survival (OS) (pâ¯=â¯.058). By data mining analysis, a 2.9-fold higher level of MICA mRNA was evidenced in tumor compared to normal tissue (pâ¯<â¯.0001). Tumors from AAM had 24% lower levels of MICA mRNA compared to tumors from CAM (pâ¯=â¯.038), and poor prognosis was found for patients with lower MICA mRNA (pâ¯=â¯.028). By flow cytometry analysis, cell fraction positive for surface MICA was of 3% in MDA-PCa-2b cells, 54% in DU-145 cells, and 67% in LNCaP cells (pâ¯<â¯.0001). sMICA was detected in DU-145 and LNCaP cells, but was not detected in MDA-PCa-2b cells. Both LNCaP and DU-145 cells were sensitive to cytolysis mediated by Natural killer (NK) cells. MDA-PCa-2b cells, however were between 1.3-fold at 10:1 Effector:Target (E:T) ratio (pâ¯<â¯.0001) and 2-fold at 50:1 E:T ratio (pâ¯<â¯.0001) more resistant to NK-mediated cytolysis relative to cells from Caucasian origin. These results suggest that MICA expression may be related to the aggressive nature of PCa. Our findings also demonstrate for the first time that there are variations in MICA expression in the context of racial differences. This study establishes a rationale for further investigation of MICA as a potential race-specific prognostic marker in PCa.
Assuntos
Negro ou Afro-Americano/genética , Regulação Neoplásica da Expressão Gênica , Antígenos de Histocompatibilidade Classe I/genética , Neoplasias da Próstata/genética , População Branca/genética , Idoso , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Perfilação da Expressão Gênica/métodos , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias da Próstata/etnologia , Neoplasias da Próstata/metabolismo , Análise de Sobrevida , Estados UnidosRESUMO
The Trypanosoma cruzi karyotype shows an extensive chromosomal size polymorphism. Absence of condensed mitotic chromosomes and chromatin fragility are characteristic features of T. cruzi which would allow DNA breaks and chromosomal rearrangements during cell proliferation. We have investigated by pulsed field gel electrophoresis (PFGE) eventual changes in chromosomal size during exponential and stationary phases of T. cruzi epimastigotes in culture, in G0 trypomastigotes and throughout the cell cycle in synchronized epimastigotes. T. cruzi molecular karyotype was stable throughout the cell cycle and during differentiation. Thus, the chromosomal size polymorphism previously reported in T. cruzi contrasts with the stability of the molecular karyotype observed here and suggests that chromosomal rearrangements leading to changes in chromosomal size are scarce events during the clonal propagation of this parasite.
Assuntos
Ciclo Celular/genética , Cromossomos/genética , Cromossomos/fisiologia , Instabilidade Genômica , Trypanosoma cruzi/citologia , Trypanosoma cruzi/genética , Animais , Diferenciação Celular , Proliferação de Células , Replicação do DNA , DNA de Protozoário/biossíntese , Genoma de Protozoário/genética , CariotipagemRESUMO
In higher eukaryotes, histone gene expression is coupled to DNA replication during the S-phase of the cell cycle. This coupling is primarily controlled at the transcriptional level. Considering the basal phylogenic position of platyhelminthes in the bilateria phylum, we have cloned a partial sequence of the histone H4 gene of Mesocestoides corti and studied its expression during the post larval development of this endoparasitic platyhelminth. In in vitro trypsin-induced tetrathyridia development to segmented adult worm, we found that histone H4 is expressed concomitantly with DNA synthesis throughout all stages of development. DNA synthesis and histone H4 mRNA levels were sharply increased at 24 h after inducing development. Afterwards, tetrathyridia grew in length from days 4 to 12 of development as proliferative cells gradually increased in number. Consequently, during this period of development histone H4 mRNA levels were upregulated. Taken together these results suggest that a replication-dependent expression pattern of histone H4 occurs in ancient bilateria, such as platyhelminthes, as previously observed in higher eukaryotes.
Assuntos
Replicação do DNA/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Histonas/biossíntese , Histonas/genética , Mesocestoides/genética , Sequência de Aminoácidos , Animais , Feminino , Proteínas de Helminto/biossíntese , Proteínas de Helminto/genética , Masculino , Mesocestoides/embriologia , Mesocestoides/crescimento & desenvolvimento , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência MolecularRESUMO
Histones from the parasitic platyhelminthes, Echinococcus granulosus and Fasciola hepatica, were systematically characterized. Core histones H2A, H2B, H3 and H4, which were identified on the basis of amino acid sequencing and mass spectrometry data, showed conserved electrophoretic patterns. Histones H1, identified on the basis of physicochemical properties, amino acid composition and amino acid sequencing, showed divergence, both in their number and electrophoretic mobilities, between the two species and among other organisms. According to these data, core histones but not H1 histones, would be stabilized during evolution at the level of platyhelminthes.
Assuntos
Cromatina/química , Echinococcus/química , Fasciola hepatica/química , Histonas/química , Histonas/isolamento & purificação , Sequência de Aminoácidos , Aminoácidos/análise , Aminoácidos/química , Aminoácidos/metabolismo , Animais , Bovinos , Cromatina/metabolismo , Cromatografia Líquida de Alta Pressão , Echinococcus/metabolismo , Eletroforese em Gel de Poliacrilamida , Fasciola hepatica/metabolismo , Histonas/genética , Histonas/metabolismo , Ouriços-do-Mar/química , Ouriços-do-Mar/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Timo/química , Timo/metabolismo , Trypanosoma cruzi/química , Trypanosoma cruzi/metabolismoRESUMO
Mesocestoides corti is a suitable model for studying cestode development because of its ability to reproduce asexually and segment in vitro. The cultured parasite is also capable of sexual differentiation and, probably, reproduction. To establish conditions that increase the efficiency of in vitro M. corti larvae (tetrathyridia) segmentation, we tested the effects of an inducing agent and some physical parameters in cultures. We found that a 5% CO2-95% N2 gas phase, an incubation temperature of 39 C (instead of 37 C), and a 24-hr pretreatment with trypsin (10(5) BAEE/ml, BAEE = Na-benzoil-L-arginine ethyl ester unit of trypsin activity) in Roswell Park Memorial Institute (RPMI) 1640 medium supplemented with 20% fetal bovine serum (FBS) are able to increase individually or synergistically the segmentation rate of tetrathyridia. A segmentation rate of up to 100% was achieved on day 4 of culture, when all these conditions were used simultaneously, in comparison with an average rate of 40% obtained not before day 11 in cultures without any inducing treatment. Fetal bovine serum is essential for segmentation, and a concentration of 20% was established as the standard for induction.
Assuntos
Mesocestoides/fisiologia , Reprodução Assexuada/fisiologia , Animais , Bovinos/sangue , Bovinos/embriologia , Meios de Cultura , Feminino , Larva/efeitos dos fármacos , Larva/fisiologia , Mesocestoides/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Ratos , Ratos Wistar , Reprodução Assexuada/efeitos dos fármacos , Temperatura , Tripsina/farmacologia , Inibidores da Tripsina/farmacologiaRESUMO
14 RN poliglobúlicos fueron sometidos a recambio parcial de sangre por plasma, usualmente llamado plasmaféresis, usando para ese propósito las principales venas y arterias de las extremidades y del cuero cabelludo. Se describe la técnica y el material usado. Este procedimiento fue fácil de realizar, no presentó complicaciones y consiguió el objetivo de reducir el hematocrito del RN. Desde la fecha de esta experiencia, en la Unidad de Neonatología del Hospital Clínico de la Universidad de Chile, no hemos vuelto a usar catéteres umbilicales para este tipo de recambio