ic-87114 and 5-(2-2-difluorobenzo(1-3)dioxol-5-ylmethylene)thiazolidine-2-4-dione

Endothelial cells play a central role in inflammatory responses, mediating leukocyte and solute traffic from blood vessels into the tissue, and are therefore key targets for anti-inflammatory therapies. Phosphoinositide 3-kinases (PI3Ks) are important signal transducers in inflammation and cancer, however there are 8 different PI3K catalytic isoforms, several of which have been shown to play distinct roles in cellular responses. Isoform-selective inhibitors have recently been described, but their effects on endothelial cell responses have not been compared. Here we compare the effects of the pan-PI3K inhibitor wortmannin with that of four more isoform-selective inhibitors, PI-103, TGX-221, AS604850 and IC87114, on endothelial cells stimulated with the pro-inflammatory cytokine TNFα. We find that PI-103 and wortmannin are most effective at reducing both endothelial permeability and leukocyte transendothelial migration (TEM), which correlates with a decrease in both the activity of the tyrosine kinase Pyk2 and its association with VE-cadherin. PI-103-related compounds are therefore likely to be good candidates for treating chronic inflammatory responses involving TNFα.

Topics: Adenine; Androstadienes; Antigens, CD; Cadherins; Capillary Permeability; Cell Membrane Permeability; Cell Shape; Class Ia Phosphatidylinositol 3-Kinase; Dioxoles; Endothelial Cells; Focal Adhesion Kinase 2; Furans; Human Umbilical Vein Endothelial Cells; Humans; Leukocytes; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Binding; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Pyridines; Pyrimidines; Quinazolines; Signal Transduction; Thiazolidinediones; TOR Serine-Threonine Kinases; Transendothelial and Transepithelial Migration; Tumor Necrosis Factor-alpha; Wortmannin

Cancer-specific mutations in the iSH2 (inter-SH2) and nSH2 (N-terminal SH2) domains of p85alpha, the regulatory subunit of phosphatidylinositide 3-kinase (PI3K), show gain of function. They induce oncogenic cellular transformation, stimulate cellular proliferation, and enhance PI3K signaling. Quantitative determinations of oncogenic activity reveal large differences between individual mutants of p85alpha. The mutant proteins are still able to bind to the catalytic subunits p110alpha and p110beta. Studies with isoform-specific inhibitors of p110 suggest that expression of p85 mutants in fibroblasts leads exclusively to an activation of p110alpha, and p110alpha is the sole mediator of p85 mutant-induced oncogenic transformation. The characteristics of the p85 mutants are in agreement with the hypothesis that the mutations weaken an inhibitory interaction between p85alpha and p110alpha while preserving the stabilizing interaction between p85alpha iSH2 and the adapter-binding domain of p110alpha.

Topics: Adenine; Amino Acid Sequence; Animals; Base Sequence; Blotting, Western; Catalytic Domain; Cell Line; Cell Proliferation; Cell Transformation, Neoplastic; Cells, Cultured; Chick Embryo; Class I Phosphatidylinositol 3-Kinases; Dioxoles; Fibroblasts; Humans; Immunoprecipitation; Morpholines; Mutation; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Binding; Protein Subunits; Pyrimidinones; Quinazolines; Thiazolidinediones; Transfection