stilbenes and herbimycin

In contrast to IgG Fc receptor II (Fc gamma RIIa), the function of Src-family kinases, Syk and phosphoinositide 3-kinase (PI3K) in signal transduction of glycosylphosphatidylinositol-anchored Fc gamma RIIIb has not been analyzed in detail. Therefore pharmacological inhibitors were used to define the role of specific kinases in signalling of Fc gamma RIIa and Fc gamma RIIIb in myeloid cells. We demonstrate that the broad tyrosine kinase inhibitor genistein, the Src-family kinase inhibitor PP2, and the Syk kinase inhibitor piceatannol inhibit [Ca2+]i rise induced by both low-affinity Fc gamma R in neutrophils. Genistein and PP2 additionally prevent Fc gamma R-triggered hydrogen peroxide generation. In contrast, wortmannin, a PI3K inhibitor, which blocks Fc gamma RIIIb activation completely, abolishes Fc gamma RIIa-mediated [Ca2+]i flux only in the beginning. In addition, herbimycin A, a further specific inhibitor of Src-family kinases leads to a delayed Fc gamma RIIa-induced [Ca2+]i rise in THP-1 cells. In summary, our data demonstrate differences between both low-affinity IgG Fc receptors, and provide evidence for an essential role of Src-family kinases, Syk and PI3K in Fc gamma RIIIb-mediated signalling.

Topics: Androstadienes; Benzoquinones; Calcium Signaling; Enzyme Inhibitors; Enzyme Precursors; Genistein; Humans; Hydrogen Peroxide; In Vitro Techniques; Intracellular Signaling Peptides and Proteins; Lactams, Macrocyclic; Neutrophils; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein-Tyrosine Kinases; Quinones; Receptors, IgG; Rifabutin; Signal Transduction; Stilbenes; Syk Kinase; Wortmannin

To investigate the role of tyrosine kinases (TK) in IgE-mediated signal transduction in human lung mast cells (HLMC) and basophils.. Peripheral blood basophils (n > or = 4) and human lung mast cells (n > or = 6).. Cells were preincubated with TK inhibitor for 15 min at 37 degrees C, before the addition of anti-IgE.. Histamine release (HR) was assayed using a fluorimetric technique. Results were compared using nonparametric statistics.. Piceatannol and ST638 significantly (p < or = 0.05) inhibited anti-IgE induced HR from HLMCs and basophils whilst lavendustin C had no effect in either cell type. Herbimycin A also significantly (p < or = 0.05) inhibited anti-IgE induced HR from both cell types, an effect which was dose dependent but did require a 16 h preincubation with drug.. In summary, HLMCs and basophils exhibit distinct inhibitory profiles in the presence of various inhibitors of TK.

Topics: Basophils; Benzoquinones; Cell Count; Cinnamates; Enzyme Inhibitors; Histamine Release; Humans; Immunoglobulin E; Lactams, Macrocyclic; Lung; Mast Cells; Phenols; Platelet Aggregation Inhibitors; Protein-Tyrosine Kinases; Quinones; Rifabutin; Signal Transduction; Stilbenes; Sulfides

The ZAP-70 tyrosine kinase is essential for T cell activation by the T cell receptor. We show that ZAP-70 is also required for migration of T cells that is dependent on the integrin LFA-1. Invasion of TAM2D2 T cell hybridoma cells into fibroblast monolayers, which is LFA-1-dependent, was blocked by overexpression of dominant-negative ZAP-70 and by piceatannol but not by herbimycin A. The Syk inhibitor piceatannol blocks the Syk homologue ZAP-70, which is expressed by TAM2D2 cells, with the same dose dependence as the inhibition of invasion. Dominant-negative ZAP-70 completely inhibited the extensive metastasis formation of TAM2D2 cells to multiple organs upon i.v. injection into mice. Migration of TAM2D2 cells through filters coated with the LFA-1 ligand ICAM-1, induced by 1 ng/ml of the chemokine SDF-1, was blocked by anti-LFA-1 mAb and also abrogated by dominant-negative ZAP-70 and piceatannol. In contrast, migration induced by 100 ng/ml SDF-1 was independent of both LFA-1 and ZAP-70. LFA-1 cross-linking induced tyrosine phosphorylation, which was blocked by dominant-negative ZAP-70 and piceatannol. We conclude that LFA-1 engagement triggers ZAP-70 activity that is essential for LFA-1-dependent migration.

Topics: Animals; Benzoquinones; Cell Movement; Chemokine CXCL12; Chemokines, CXC; Fibroblasts; Gene Expression; Humans; Hybridomas; Integrins; Intercellular Adhesion Molecule-1; Lactams, Macrocyclic; Lymphocyte Function-Associated Antigen-1; Mice; Neoplasm Metastasis; Phosphotyrosine; Protein-Tyrosine Kinases; Quinones; Rats; Rifabutin; Stilbenes; T-Lymphocytes; Virulence Factors, Bordetella; ZAP-70 Protein-Tyrosine Kinase