Dinitrosyl iron complexes with thiol-containing ligands and S-nitroso-D,L-penicillamine as inductors of heat shock protein synthesis in H35 hepatoma cells.

The concentration-dependent effect of various nitric oxide donors on synthesis of different heat shock proteins was evaluated in Reuber H35 hepatoma cells and their heat shock protein-inducing ability was compared with the effect of a heat shock. A 6 h incubation of H35 cells with the dimeric (diamagnetic) form of dinitrosyl iron complex with glutathione or N-acetyl-L-cysteine activated synthesis of various heat shock proteins, heat shock protein 28, 32, 60, 70, 90 and 100. Synthesis of these proteins was evaluated by [35S]methionine and [35S]cysteine labelling with subsequent separation of proteins by polyacrylamide gel electrophoresis. The dinitrosyl iron complex with glutathione appeared to be the most efficient inductor of heat shock protein synthesis and initiated the synthesis of heat shock protein 28 even more efficiently than a 30 min heating of cells. In the same experiments, S-nitroso-D,L-penicillamine exerted a considerably lesser effect on the synthesis of heat shock proteins. It was suggested that the active moiety of dinitrosyl iron complexes as inductors of heat shock protein synthesis is represented by their Fe+(NO+)2 groups which move to thiol groups of the proteins participating in the initiation of heat shock protein synthesis.