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
Aging results in a general decline in the response to external insults, including acute inflammatory challenges. In young animals, the inflammatory response requires activation of the sympathetic system, including neurotransmitters such as ATP, and catecholamines (epinephrine and norepinephrine). To test whether aging affects activation of this axis, and whether this in turn might affect cytokine release, we administered lipopolysaccharide (LPS) i.p. to adult, middle-aged and aged Fisher 344 rats (6-, 15- and 23-month old, respectively) and evaluated the early (0-12h) serum levels of Neuropeptide-Y (NP-Y), ATP and vanillyl mandelic acid (VMA, as an indirect measurement of catecholamine levels). In addition, we evaluated the association between these factors and serum levels of the cytokines tumor necrosis factor-alpha (TNFalpha) and interleukin-10 (IL-10). Induction of both ATP and NP-Y was markedly reduced in the serum of aged animals, when compared to their younger counterparts, while induction of VMA was not affected by age. In spite of these changes, serum levels of TNFalpha and IL-10 were strongly hyper induced and delayed in aged rats. The results suggest that during aging there is a dysregulation in sympathetic neurotransmitter regulatory mechanisms, and this might play a role in the impairment of the inflammatory response.
Assuntos
Envelhecimento/imunologia , Envelhecimento/fisiologia , Citocinas/biossíntese , Inflamação/imunologia , Inflamação/fisiopatologia , Neurotransmissores/metabolismo , Trifosfato de Adenosina/sangue , Animais , Citocinas/sangue , Interleucina-10/sangue , Lipopolissacarídeos/toxicidade , Masculino , Modelos Neurológicos , Neuroimunomodulação , Neuropeptídeo Y/sangue , Neurotransmissores/sangue , Ratos , Ratos Endogâmicos F344 , Sistema Nervoso Simpático/metabolismo , Transmissão Sináptica , Fator de Necrose Tumoral alfa/sangue , Ácido Vanilmandélico/sangueRESUMO
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
There is considerable controversy about the molecular mechanisms responsible for the variations in innate immunity associated with age. While in vivo, aged animals and humans react to an inflammatory signal with an excessive production of pro-inflammatory cytokines, studies in vitro generally show that this response is attenuated in macrophages from old individuals. In an effort to examine possible extrinsic factors that might affect the response of macrophages to lipopolysaccharide (LPS), we have challenged peritoneal macrophages obtained from young rats with sera obtained from rats of different ages. Our results indicate that the serum from aged rats significantly impairs the capacity of young macrophages to induce tumor necrosis factor-alpha (TNF-alpha) production, while at the same time it increases the basal levels of interleukin-6 (IL-6). The effect of serum from aged donors on TNF-alpha secretion requires pre-incubation and is sensitive to heat inactivation. In contrast, the stimulating effect on IL-6 is resistant to heat, and thus should not be due to a protein factor. Therefore, our results indicate that the age-related changes in macrophage activity are not only the consequence of intrinsic changes, but there also appears to be a modulatory effect imparted by the external milieu.