Identification of genes differentially expressed by putrescine in HepG2 hepatoblastoma cells

In order to identify genes differentially expressed by putrescine, a polyam ine, which play important roles in the regulation of cell proliferation and the development of cancer, we performed mRNA differential display analysis using total RNA extracted from HepG2 cells (human hepatoblastoma cell line ) treated with a specific inhibitor of polyamine biosynthesis, alpha -diflu orometylornithine (DFMO). A total of 25 genes were up-regulated and 32 gene s down-regulated by putrescine. Of the genes differentially expressed by pu trescine, we chose three that were related to the respiratory chain and oxi dative phosphorylation and analyzed them by Northern blot analysis. Cytochr ome oxidase subunit 1, low molecular mass ubiquinone-binding protein, and N ADH dehydrogenase subunit 2 were found to be downregulated by putrescine. W e examined intracellular ATP level in HepG2 cells, and found that ATP level in DFMO-treated cells was increased by exogenous putrescine. (C) 2001 Else vier Science Ireland Ltd. All rights reserved.