RESUMO
Gliomas of astrocytic origin are the most common primary brain tumors, accounting for over 40 to 50 of all central nervous system tumors. The TP53 tumor suppressor gene is the most frequently mutated gene found in human malignancies. A mutation of this gene can lead to an increased half-life of the resulting protein and loss of biological function. High levels of p53 have been detected in the serum of colon cancer patients, although p53 protein has not been detected in the serum of brain tumor patients. Besides circulating p53, several studies have detected antibodies against p53 in patients with lung and breast cancer, as well as those with other types of cancer. We studied p53 protein and anti-p53 antibodies in the plasma of Brazilian brain tumor patients. Plasma samples were drawn from 24 untreated brain tumor patients and from 15 healthy donors without clinical signs of cancer. Western blotting techniques were used to detect p53 protein and anti-p53 antibodies. We found anti-p53 antibodies in 5/24 brain tumor patients. Age appears to affect the immune response, as four of six tumor patients under 16 years old had detectable anti-p53 antibodies, while these were found in only 1 of 18 adults (over 16 years old). We found no p53 protein in any of the serum samples from the brain tumors. Possibly the presence of this protein is affected by tumor type or by the organs that are sampled
Assuntos
Humanos , Masculino , Feminino , Pré-Escolar , Criança , Adolescente , Adulto , Pessoa de Meia-Idade , Anticorpos Antineoplásicos/sangue , /imunologia , Glioma/imunologia , Neoplasias Encefálicas/imunologia , Proteína Supressora de Tumor p53 , Western Blotting , Brasil , /genética , Glioma/sangue , Glioma/genética , Mutação , Neoplasias Encefálicas/sangue , Neoplasias Encefálicas/genética , Proteínas Recombinantes/sangue , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Proteína Supressora de Tumor p53RESUMO
We analyzed alterations in CDKN2 in gliomas from an ethically mixed population and correlated the results with patients clinical data. We screened for methylation at CDKN2 and for microsatellite instability (MSI) and loss of heterozygosity (LOH) in the region 9p21-22 using 4 markers. We found: 3/30 (10%) cases with CDKN2-methylated gliomas; an average of 4% of MSI; and 24.5% of LOH in the region 9p21-22. Methylation of CDKN2 was only detected in patients showing high-grade gliomas with short survival. MSI and LOH in the region 9p21-22 were detected in patients showing high-grade gliomas with short survival and in one patient with a recurrent low-grade astrocytoma grade II who died from the disease after 3 years, indicating that such alterations represent poor prognosis.
Assuntos
Neoplasias Encefálicas/genética , Inibidor p16 de Quinase Dependente de Ciclina/genética , Glioma/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Encefálicas/mortalidade , Criança , Cromossomos Humanos Par 9/genética , Metilação de DNA , DNA de Neoplasias/genética , Feminino , Glioma/mortalidade , Humanos , Perda de Heterozigosidade , Masculino , Repetições de Microssatélites/genética , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Prognóstico , Taxa de SobrevidaAssuntos
Carcinoma de Células Pequenas/genética , DNA de Neoplasias/sangue , Proteínas de Ligação a DNA/sangue , Neoplasias Pulmonares/genética , Idoso , Western Blotting , Carcinoma de Células Pequenas/sangue , Eletroforese em Gel de Poliacrilamida , Feminino , Humanos , Neoplasias Pulmonares/sangueRESUMO
We have verified the presence of line-1 retrotransposon (L1) in plasma DNA in 15/17 brain tumor (glioma) patients and in 6/6 healthy people by applying PCR amplification of part of the L1 5' end. The same samples were separately amplified for K-ras. Results suggested that L1 sequences are circulating throughout the body. We hypothesized the participation of transposable elements such as L1 in a putative DNA release mechanism.
Assuntos
Neoplasias Encefálicas/genética , DNA de Neoplasias/genética , Glioma/genética , Elementos Nucleotídeos Longos e Dispersos , Adulto , Idoso , Sequência de Bases , Primers do DNA , DNA de Neoplasias/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da PolimeraseRESUMO
Small amounts of plasma-free DNA have been observed both in healthy individuals and in patients with various diseases such as systemic lupus erythematosus, rheumatoid arthritis, viral hepatitis, and cancer. This communication demonstrates that septic patients also release DNA in plasma. After DNA extraction from plasma, exon 1 of the K-ras gene was amplified by PCR and products were analyzed by dot-blot hybridization. Plasmas from polytraumatic patients and control healthy individuals were used for comparisons with septic patients. Our results show that septic patients present DNA in their plasma. As far as we know, this is the first evidence of circulating DNA in septic patients.
Assuntos
DNA/sangue , Sepse/sangue , Sepse/genética , Sequência de Bases , Fluorescência , Humanos , Hibridização de Ácido Nucleico , Reação em Cadeia da PolimeraseRESUMO
Circulating DNA and oncoproteins can be extracted from serum or plasma of cancer patients. In this study, using gel retardation analysis we observed circulating DNA obtained from plasma of a lung cancer patient complexed with serum proteins. p53 was identified by immunoblotting as one of the proteins present in the complex. Our finding suggests that the same interaction observed between p53 and DNA in intact cells occurs in serum of lung cancer patient. As far as we know this is the first evidence for such finding.
Assuntos
Proteínas Sanguíneas/metabolismo , Carcinoma de Células Pequenas/sangue , DNA/metabolismo , Neoplasias Pulmonares/sangue , Idoso , Carcinoma de Células Pequenas/patologia , DNA/sangue , Eletroforese em Gel de Poliacrilamida , Feminino , Humanos , Immunoblotting , Neoplasias Pulmonares/patologia , Nucleoproteínas/análise , Ligação Proteica , Proteína Supressora de Tumor p53/análiseRESUMO
The influence of extracellular calcium concentration on mosquito cells was investigated in Aedes albopictus cells cultured in a medium with different amounts of calcium. Protein synthesis in cells incubated in low calcium culture medium was inhibited when compared to control cells. This inhibition was reversed by addition of calcium to the culture medium. Two calcium-induced proteins of approximately 70,000 and 80,000 daltons were detected when calcium was added to the extracellular medium of cells incubated in low calcium medium for longer than 2 h. Northern-blot analysis indicated that Hsp70 (heat shock protein of 70,000 dalton) specific mRNA is present in cells that were cultured in low calcium medium suggesting that the 70,000 dalton protein is a member of the Hsp70 family. Our results indicate that extracellular calcium concentration can modify the gene expression pattern in A. albopictus cells and the absence of calcium in the culture medium could be considered a stress factor.
