Perfil de expressão genica de leucemias agudas por tecnica de microarranjo (microarrays) / Study of gene expression profile in acute leukemias by microarray assay

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The development of gene expression assays, such as cDNA microarrays, has permitted the simultaneous study of several genes; one of this methods is the cDNA microarrays. These investigations contribute to the classification of diseases, comprehension of tumoral biology and, finally, the determination of genetically related prognostic factors. In this present study, the gene expression profiles were analysed for 17 cases of Acute Myeloid Leukemia (AML), 5 cases of Acute Lymphocytic Leukemia (ALL) and 4 samples of peripheral blood apheresis, after stimulation with G-CSF for alogenic transplantation donors. For the microarray assays, membranes containing approximately 4700 spots were developed by the Ludwig Institute for Cancer Research, with contribution and financial support of FAPESP, using cDNA cloned from the Human Cancer Genome Project. The main advantages of these membranes include (1) availability of a cDNA library constructed by the ORESTES methodology, which makes the cDNA clones more representative of the whole transcriptome, (2) the non-comercial characterization of human transcripts, which may be vantageous for finding new genes and/or ESTs not diffusely disponible in large-scale production and, (3) since the library is contructed from different tumoral tissues, it may constitute the best representation of the tumorigenesis process. The methodology efficiently distinguished a group of genes, supporting the identification of the ALL, AML and control samples by the Wilcoxon Statistical Analysis and the supervised and non-supervised Hierarchical Clusterization developed by Eisen. Among the genes that were differentially expressed when comparing AML and ALL, it was possible to observe genes related to specific cellular processes such as: in the AML group nucleotides metabolism regulation pathways, adhesion and cell signaling (SS2XIP, MUC4, THBS1 e RGL2), signal transduction, especially in the Wnt pathway and Ras and Rho from the ?Small GTPases? pathway (RGL2, ARGHAP1, CDKN1B and beta-catenin), and in the ALL a group of apoptotic regulators genes such as BIRC6, SH3GLB1, PSEN1 e NFKB1 among. The microarray efficiently to distinguished genes related to M3-AML and non-M3-AML, showing differentially expressed genes not previosly described in the literature to be related to the specific sbtype M3-AML, such as TLE1, PSCDBP, SMG1, TALDO1, CUL1, TBX1, UBXD8, genes associated with programmed cell death and cell cycle, and components of Groucho/TLE complex, which functions like a repressor of transcriptional activity induced by the Wnt pathway. The results were validated through the utilization of Real Time PCR in five selected genes, tested in a greater number of cases (n=50 acute leukemia samples). In 4 of these genes the results were completely confirmed, demonstrating that the microarray technology with the 3.7K Ludwig Institut/FAPESP membranes was efficient for screening genes possibly related to specific leukemias subtypes, particularly the ALL and M3-AML groups. As such, the utilization of microarray methodology with sequences derived from the Cancer Genome Project (Ludwig Institut/FAPESP) permitted the distinction of important metabolic pathways for the tumorigenesis process, some of them associated to specific leukemic subtypes, and the recognition of differentially expressed genes not before described in the literature

ASSUNTO(S)

apoptose apoptosis expressão genica proliferação celular cell proliferation acute leukemia gene expression leucemia aguda

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