Expression profile of genes altered by NO-donating aspirin in T-leukemia cells.

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Acute leukemia is the primary cause of cancer-related mortality in children. ß -catenin, a regulator of cell-cell adhesion and transcription, is expressed in T-acute lymphoblastic leukemia cells, tumor lines of hematopoietic origin and primary leukemia cells but not in normal peripheral blood T cells. Nitric oxide-donating aspirin (NO-ASA), comprising of a traditional ASA molecule covalently bound to an -ONO₂ moiety via an aromatic spacer is emerging as an effective chemopreventative agent against colon and other cancers. We have examined the effects of NO-ASA on the growth of Jurkat T-acute lymphoblastic leukemia cells and on the fate of ß -catenin and have reported cell growth inhibition and caspase-mediated degradation of beta catenin (BBRC 2005:326, 93-99). Here we have investigated whether NO-ASA may alter the gene expression of other biological and signaling pathways that are potential targets in carcinogenesis. mRNA was isolated from control and NO-ASA-treated (10 µM, 18 hr) Jurkat cells and labeled according to standard protocols and kits. The cDNA arrays set from SuperArray, Bioscience Corporation were used. The blots were hybridized and the ratios of the expression levels quantified and calculated. The following are potential candidate genes whose expression were altered in response to NO-ASA: HSP70, grp78, HSPD1 chaperonin , glutathione reductase (GSR) and E2F1. Among these, the interesting candidates are the GRPs which are known to promote tumor proliferation and metastasis, GSR, which is important member of the oxidative stress pathway, and E2F1 which is a critical regulator of the cell cycle. The relationship of their gene expression with the cell growth inhibition observed by NO-ASA will be discussed. These studies will address the mechanisms of action of NO-ASA in T leukemia cells.