Programa de Pós-Graduação em Oncologia e Ciências Médicas - PPGOCM/NPO

URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/4631

O Programa de Pós-Graduação em Oncologia e Ciências Médicas (PPGOCM) integra o Núcleo de Pesquisas em Oncologia (NPO) da Universidade Federal do Pará (UFPA). Trata-se do único centro de referência em pesquisa e formação de recursos humanos stricto sensu na área de oncologia na região Norte do Brasil. Os outros centros se concentram nas cidades do Rio de Janeiro e São Paulo.

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Agora exibindo 1 - 2 de 2

Acesso aberto (Open Access)
Análise da expressão de hsa-miR-9 e CDH1 em adenocarcinoma gástrico
(Universidade Federal do Pará, 2016-06-02) OLIVEIRA, Kelly Cristina da Silva; CALCAGNO, Danielle Queiroz; http://lattes.cnpq.br/1326603355062154
The loss of CDH1 expression is a frequent event in gastric cancer (GC), in sporadic and hereditary manifestation, important in the invasion and metastasis process. Approximately, 15-50% of families affected by hereditary diffuse gastric cancer syndrome (HDGC) have germline mutations in the CDH1 gene. Evidences established that hsa-miR-9 participates of this protein downregulation in breast cancer and hepatocellular carcinoma. In the present study, we investigated the possibility of hsa-miR-9 is involved in CDH1 negative regulation in HDGC and sporadic GC. For the relative quantification of hsa-miR-9 expression by real-time PCR, was used samples from 9 patients with HDGC and paired samples of sporadic GC and adjacent non-neoplasic gastric tissue of 138 patients. Additionally, was performed copy number variation analysis of the MYC gene, a positive regulator of has-miR-9, in HDGC samples. The expression of CDH1 mRNA and its protein in sporadic GC samples were performed by real time PCR and Western Blot, respectively. All HDGC samples, exhibited increased of hsa-miR-9 expression and copies number of MYC (≥3 copies) independent of the presence of germline mutation in CDH1 gene. In sporadic GC it was detected a reduction of CDH1 mRNA expression, CDH1 and hsa-miR-9. Moreover, was found a significant association of CDH1 reduced expression in diffuse-type tumors and advanced. The reduction of CDH1 mRNA expression, CDH1 and hsa-miR-9 was significantly associated with lymph node metastasis and tumor stage III-IV. In correlation analysis, was identified a very strong correlation between the expression of mRNA and protein of CDH1, and a strong correlation between the CDH1 mRNA expression and hsa-miR-9, and the protein expression of CDH1 and hsa-miR-9. The hsa-miR-9 takes a controversial role in CG according to the type of manifestation, playing oncomiR paper in HDGC, occasionally behaving like tsmiR in sporadic. In HDGC, we suggest that hsa-miR-9 overexpression could be influenced by MYC amplification and that it functions as a second event mechanism in patients with germline mutation in the gene CDH1. Regarding sporadic GC, as an alternative hypothesis based on the theory of field cancerization, we suggest that there is an increased expression of hsa-miR-9 in the adjacent stomach tissue compared to the gastric tissue without cancer. This overexpression would be higher in adjacent tissue than in the tumor, leading to downregulation of CDH1, important for epithelial-mesenchymal transition and tumor initiation.
Acesso aberto (Open Access)
Expressão dos genes TFF1 e TFF2 em adenocarcinoma gástrico
(Universidade Federal do Pará, 2014-01-24) HAGE, Pedro Antônio Mufarrej; CALCAGNO, Danielle Queiroz; http://lattes.cnpq.br/1326603355062154; ASSUMPÇÃO, Paulo Pimentel de; http://lattes.cnpq.br/7323606327039876
Gastric cancer remains a serious public health problem with high morbidity and mortality. Generally, the diagnoses occur in advanced disease when the available therapeutic options have limited effectiveness. Despite advances in the understanding of carcinogenesis of gastric adenocarcinoma, particularly on genetic and epigenetic mechanisms involved, the clinical aplicabilitadade such knowledge remains limited. In order to identify potential biomarkers in gastric cancer, we conducted a study using microarray comparing gene expression in gastric adenocarcinomas and paired samples of non- neoplastic gastric mucosa. Preliminary, the results showed significant differences in expression of 53 genes. Among these, the TFF1 and TFF2 genes were selected for validation of expression by real-time PCR in 78 additional samples. Expression of TFF1 and TFF2 were significantly reduced in samples of gastric adenocarcinoma when you compare the paired non-neoplastic tissues (p<0.05). Additionally, the TFF2 gene expression was significantly lower in the intestinal subtype than in the diffuse subtype. The expression of the two genes showed a strong correlation, the similar pattern of expression suggests that TFF1 and TFF2 may have common regulatory elements. This hypothesis is enhanced due to the small physical distances between them. The results suggest the involvement of TFF1 and TFF2 in gastric carcinogenesis and demonstrate the potential for clinical use of these genes as biomarkers and potential therapeutic targets in gastric adenocarcinoma.

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