s-nitro-n-acetylpenicillamine and Leukemia

Nitric oxide (NO) and serotonin (5-hydroxytryptamine; 5-HT) are important neuromodulators that are involved in a myriad of biochemical reactions. In this work, we describe a novel model co-culture system to study the interactions between NO and 5-HT. NO derived from cytokine stimulated Bv2 microglial cells depleted 5-HT from RBL-2H3 cells. Reduction of 5-HT content by NO derived from the NO donor S-nitroso-N-acetylpenicillamine (SNAP) was concentration-dependent, independent of intracellular Ca(2+) and inhibited by reduced glutathione (GSH). Collectively, these data indicate that this cell co-culture system is a viable model to study the mechanisms of interaction between nitrergic and serotonergic pathways.

Topics: Animals; Calcium; Cell Line; Citrulline; Coculture Techniques; Dose-Response Relationship, Drug; Glutathione; Leukemia; Microglia; Nitric Oxide; Penicillamine; Rats; Serotonin; Tumor Cells, Cultured

Intracellular nitric oxide levels may differ in resting and stimulated cells and contribute to the regulation of cell survival and proliferation through a variety of mechanisms and effects. We exposed two B-cell lines to a range of S-nitroso-N-acetyl-D,L-penicillamine (SNAP) concentrations in order to examine their susceptibility to exogenous nitric oxide and the participation of nitric oxide as modulator of cell proliferation. Although both FLEB and NALM-6 decreased their levels of thymidine incorporation, only NALM-6 cells were induced to undergo G1 arrest, phosphatidyl serine exposure and DNA fragmentation when cultured in the presence of 250 microm SNAP. This higher sensitivity of NALM-6 coincided with initially low cyclin E protein levels which were increased 7.8-fold after culture for 24 h with 250 microm SNAP. In contrast, there was no difference in cyclins A and D3, Bcl-2 and actin levels, neither at the beginning nor at the end of the 24 h culture. Our study reveals that FLEB and NALM-6 exhibit different response to the same concentration of nitric oxide, that nitric oxide can simultaneously induce cell cycle alterations and apoptosis, and further suggests an association between these two processes, with the involvement of cell cycle regulatory molecules.

Topics: Actins; Apoptosis; B-Lymphocytes; Blotting, Western; Cell Cycle; Cell Separation; Cyclin A; Cyclin D3; Cyclin E; Cyclins; DNA Fragmentation; Flow Cytometry; G1 Phase; Leukemia; Nitric Oxide; Penicillamine; Phosphatidylserines; Proto-Oncogene Proteins c-bcl-2; Thymidine; Time Factors; Tumor Cells, Cultured