Analysis of gene expression in Egr-1 transfected human fibrosarcoma cells

Background and Objectives: It has been shown previously that transcription factor Egr-1 functions as a tumor suppressor gene. This study was conducted to investigate the possible mechanisms responsible for this function. Methods: A cDNA microarray technique was applied to study differential gene expression between Egr-1-transfected cells and control-transfected cells. Results: A number of genes differentially expressed were identified. Among 5,184 genes examined by cDNA microarray technique, 53 were up-regulated in Egr-1 transfected cells, and 276 were down-regulated in Egr-1 transfected cells by at least two times or more; 13 genes were independently confirmed by reverse transcription polymerase chain reaction (RT-PCR). Of these 13 genes, 11 were in agreement with cDNA microarrays in terms of gene expression levels. Conclusions: Egr-1 regulated almost every category of genes according to gene ontology system, and repressed more genes than it induced. The identification and further characterization of genes regulated by Egr-1 should provide valuable information to understand Egr-1 tumor suppressor action and the role of Egr-1 as a transcription factor in general.