RESUMO
Pancreatic ductal adenocarcinoma (PDAC) remains an important cause of malignancy-related death and is the eighth most common cancer with the lowest overall 5-year relative survival rate. To identify new molecular markers and candidates for new therapeutic regimens, we investigated the gene expression profile of microdissected cells from 11 normal pancreatic ducts, 14 samples of PDAC, and 4 well-characterized pancreatic cancer cell lines using the Affymetrix U133 GeneChip set. RNA was extracted from microdissected samples and cell lines, amplified, and labeled using a repetitive in vitro transcription protocol. Differentially expressed genes were identified using the significance analysis of microarrays program. We found 616 differentially expressed genes. Within these, 140 were also identified in PDAC by others, such as Galectin-1, Galectin-3, and MT-SP2. We validated the differential expression of several genes (e.g., CENPF, MCM2, MCM7, RAMP, IRAK1, and PTTG1) in PDAC by immunohistochemistry and reverse transcription polymerase chain reaction. We present a whole genome expression study of microdissected tissues from PDAC, from microdissected normal ductal pancreatic cells and pancreatic cancer cell lines using high-density microarrays. Within the panel of genes, we identified novel differentially expressed genes, which have not been associated with the pathogenesis of PDAC before.
Assuntos
Carcinoma Ductal Pancreático/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Pancreáticas/genética , Idoso , Carcinoma Ductal Pancreático/diagnóstico , Carcinoma Ductal Pancreático/patologia , Proteínas de Ciclo Celular/análise , Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/análise , Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA/análise , Proteínas de Ligação a DNA/genética , Feminino , Perfilação da Expressão Gênica , Humanos , Masculino , Microdissecção , Proteínas dos Microfilamentos , Pessoa de Meia-Idade , Componente 2 do Complexo de Manutenção de Minicromossomo , Componente 7 do Complexo de Manutenção de Minicromossomo , Proteínas Nucleares/análise , Proteínas Nucleares/genética , Análise de Sequência com Séries de Oligonucleotídeos , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/patologia , Regulação para CimaRESUMO
In a search for new molecular markers of pancreatic ductal adenocarcinoma (PDAC), we compared the gene expression profiles of seven pancreatic carcinomas and one carcinoma of the papilla Vateri with those of duct cells from three non-neoplastic pancreatic tissues. In addition, the human pancreatic duct cell line and five PDAC cell lines (AsPC-1, BxPC-3, Capan-1, Capan-2, HPAF) were examined. RNA was extracted from microdissected tissue or cultured cell lines and analysed using a custom-made Affymetrix Chip containing 3023 genes, of which 1000 were known to be tumour associated. Hierarchical clustering revealed 81 differentially expressed genes. Of all the genes, 26 were downregulated in PDAC and 14 were upregulated in PDAC. In PDAC cell lines versus normal pancreatic duct cells, 21 genes were downregulated and 20 were upregulated. Of these 81 differentially expressed genes, 15 represented human genes previously implicated in the tumourigenesis of PDAC. From the genes that were so far not known to be associated with PDAC tumorigenesis, we selected ADAM9 for further validation because of its distinct overexpression in tumour tissue. Using immunohistochemistry, the over-expressed gene, ADAM9, was present in 70% of the PDACs analysed. In conclusion, using microarray technology we were able to identify a set of genes whose aberrant expression was associated with PDAC and may be used to target the disease.
Assuntos
Adenocarcinoma/genética , Carcinoma Ductal Pancreático/genética , Perfilação da Expressão Gênica , Neoplasias Pancreáticas/genética , Idoso , Feminino , Humanos , Masculino , Microdissecção , Pessoa de Meia-Idade , Análise de Sequência com Séries de OligonucleotídeosRESUMO
BACKGROUND: There is increasing knowledge about the genetic basis of pancreatic cancer (PaCa). Tumor suppressor genes (TSGs; e.g. p53 and DPC4) and oncogenes (e.g. K-ras) have been shown to be involved in the development of PaCa. However, the extent of chromosomal changes (gains and losses) implicates that many more genes may be involved in the multistep progression of PaCa. Identification of these genes is essential for understanding the molecular events in the development of PaCa. METHODS: We assembled public and proprietary libraries of more than 4 million expressed sequence tags using newly developed software tools. RESULTS: We identified a total of 249 genes with specific expression patterns in normal and cancerous tissue of the pancreas. Of these, 27 genes were found to be preferentially expressed in normal tissue of the pancreas, while 222 genes showed significant upregulation of expression in PaCa. Of the 249 genes, 232 (93.2%) were found to represent known human genes or putative human homologues of genes characterized previously in other species, while 17 (6.8%) represent putative new genes. CONCLUSION: These genes may represent a valuable source to identify novel TSGs and oncogenes involved in the carcinogenesis of PaCa.
