Control of survival of proliferating L1210 cells by soluble guanylate cyclase and p44/42 mitogen-activated protein kinase modulators

• Published in: Biochemical pharmacology 2001-08, Vol.62 (3), p.319-328
• Main Authors: Flamigni, Flavio, Facchini, Annalisa, Stanic, Ivana, Tantini, Benedetta, Bonavita, Francesca, Stefanelli, Claudio
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis; Biological and medical sciences; Caspase; Caspases - metabolism; Cell Division - drug effects; Cell Division - physiology; Cell physiology; Cell Survival - drug effects; Cell Survival - physiology; Cyclic GMP - metabolism; Enzyme Activation; Enzyme Inhibitors - pharmacology; Fundamental and applied biological sciences. Psychology; Guanylate Cyclase - antagonists & inhibitors; Guanylate Cyclase - physiology; Imidazoles - pharmacology; Leukemia; Leukemia L1210 - pathology; Mice; Mitogen-activated protein kinase; Mitogen-Activated Protein Kinase 1 - antagonists & inhibitors; Mitogen-Activated Protein Kinase 1 - physiology; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases - antagonists & inhibitors; Mitogen-Activated Protein Kinases - physiology; Molecular and cellular biology; ODQ; Oxadiazoles - pharmacology; Oxidation-Reduction; Proto-Oncogene Proteins c-bcl-2 - metabolism; Pyridines - pharmacology; Quinoxalines - pharmacology; Signal Transduction; Tumor Cells, Cultured
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/S0006-2952(01)00646-3

Intracellular signaling pathways involved in the survival of proliferating L1210 leukemia cells were investigated by using specific modulators. Among the various inhibitors tested, only 1 H-[1,2,4]oxadiazole [4,3- a]quinoxalin-1-one (ODQ), a soluble guanylate cyclase (sGC) inhibitor, was found to induce a marked increase in caspase activity, which was associated with a loss of cell viability and a reduction in cGMP content. ODQ also provoked the processing of caspases-3 and -9, release of cytochrome c and, as early events, reduction of Bcl-2 content and dephosphorylation of Bad at Ser 112. Furthermore, YC-1, an sGC activator, and 8-Br-cGMP, a cell-permeant analogue of cGMP, exerted some protection against various apoptotic stimuli, such as serum deprivation or spermine accumulation. Although PD98059 (2′-amino-3′-methoxyflavone), an inhibitor of the p44/42 mitogen-activated protein kinase (MAPK) pathway, did not increase basal caspase activity, and ODQ did not affect p44/42 MAPK phosphorylation significantly, phorbol myristate acetate stimulated p44/42 MAPK and reduced caspase activation induced by ODQ, serum deprivation, and spermine in a p44/42-dependent manner. SB203580 (4-(4-fluorophenyl)-2-(4-methylsulfonylphenyl)-5-(4-pyridyl)1 H-imidazole), a p38 MAPK inhibitor, also partially protected against ODQ-induced apoptosis by increasing p44/42 MAPK phosphorylation. In conclusion, these results suggest that sGC may be relevant both for survival of L1210 cells under basal growing conditions and for protection against various apoptotic stimuli. p44/42 MAPK activation may also confer some protection from apoptosis, but apparently through a pathway largely independent of cGMP.