Navegando por Palavras-chave "protein expression"

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    hTERT methylation and expression in gastric cancer
    (Taylor & Francis Ltd, 2009-01-01) Gigek, Carolina Oliveira; Leal, Mariana Ferreira; Oliveira Silva, Patricia Natalia; Frias Lisboa, Luara Carolina; Lima, Eleonidas Moura; Calcagno, Danielle Queiroz; Assumpcao, Paulo Pimentel; Burbano, Rommel Rodriguez; Cardoso Smith, Marilia de Arruda [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Fed Univ Para
    Gastric cancer is the second most prevalent cause of cancer death worldwide. DNA methylation is a common event in gastric carcinogenesis. hTERT seems to be the rate-limiting determinant of telomerase activation, which is responsible for stability and life span. hTERT hypermethylation has been associated with telomerase expression. in the present study, we investigated the promoter methylation status and hTERT protein expression in gastric cancer and normal mucosa samples. One hundred and nine gastric cancer and 53 normal mucosa samples were investigated through methylation-specific PCR. Immunohistochemistry was analysed using peroxidase in 55 gastric cancer and 18 normal gastric mucosa samples. This is the first study evaluating hTERT methylation status in gastric carcinogenesis. We did not observe hTERT protein expression in normal gastric mucosa. Moreover, hTERT expression was observed in 80% of tumours and was associated with gastric cancer (p < 0.0001). Partial methylation was the most frequent pattern in gastric samples, even in normal mucosa. the frequency of specimens presenting hypermethylation was significantly higher in tumours than in normal mucosa samples (p = 0.0002), although the presence of hypermethylated promoter was not associated with a higher frequency of hTERT expression. A low correlation between hTERT protein expression and methylation was verified in gastric cancer samples. There was a clear difference in the frequency of hTERT expression and methylation within tumoral and non-tumoral tissues. Methylation status and telomerase expression may be useful for the diagnosis of gastric cancer and may have an impact on the anti-telomerase strategy for cancer therapy.
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    A new Paracoccidioides brasiliensis 70-kDa heat shock protein reacts with sera from paracoccidioidomycosis patients
    (Taylor & Francis Ltd, 2005-09-01) Bisio, L. C.; Silva, S. P.; Pereira, I. S.; Xavier, MAS; Venancio, E. J.; Puccia, R.; Soares, CMA; Felipe, MSS; Universidade de Brasília (UnB); Universidade Federal de Goiás (UFG); Universidade Federal de São Paulo (UNIFESP); Universidade Estadual de Londrina (UEL); Novo Nordisk Prod Farmaceut Brasil
    A cDNA coding for a new member of the 70-kDa heat shock proteins (HSP70) family from the dimorphic and pathogenic fungus, Paracoccidioides brasiliensis, was cloned and characterized. the cDNA-deduced sequence coded for 655 amino acid residues and showed 95% identity to a previously described P. brasiliensis hsp70 gene. Cytoplasmic and typical nuclear localization signals, which indicate induction upon stress, were identified in the deduced peptide. the complete hsp70 cDNA coding region was cloned into a pGEX 4T-3 plasmid and expressed in Escherichia coli as a glutathione-S-transferase-tagged fusion protein. the recombinant protein reacted with a rabbit polyclonal antibody against HSP70. Western immunoblot experiments demonstrated that sera from paracoccidioidomycosis patients recognized the purified recombinant protein, suggesting an immunological role for this protein in the infectious process. the antigenicity analysis of rHSP70 detected three internal peptides that could act as activators of T-cell proliferation.