Jean-Pierre Evenou

The Potent Protein Kinase C-Selective Inhibitor AEB071 (Sotrastaurin) Represents a New Class of Immunosuppressive Agents Affecting Early T-Cell Activation

There is a pressing need for immunosuppressants with an improved safety profile. The search for novel approaches to blocking T-cell activation led to the development of the selective protein kinase C (PKC) inhibitor AEB071 (sotrastaurin). In cell-free kinase assays AEB071 inhibited PKC, with Ki values in the subnanomolar to low nanomolar range. Upon T-cell stimulation, AEB071 markedly inhibited in situ PKCθ catalytic activity and selectively affected both the canonical nuclear factor-κB and nuclear factor of activated T cells (but not activator protein-1) transactivation pathways. In primary human and mouse T cells, AEB071 treatment effectively abrogated at low nanomolar concentration markers of early T-cell activation, such as interleukin-2 secretion and CD25 expression. Accordingly, the CD3/CD28 antibody- and alloantigen-induced T-cell proliferation responses were potently inhibited by AEB071 in the absence of nonspecific antiproliferative effects. Unlike former PKC inhibitors, AEB071 did not enhance apoptosis of murine T-cell blasts in a model of activation-induced cell death. Furthermore, AEB071 markedly inhibited lymphocyte function-associated antigen-1-mediated T-cell adhesion at nanomolar concentrations. The mode of action of AEB071 is different from that of calcineurin inhibitors, and AEB071 and cyclosporine A seem to have complementary effects on T-cell signaling pathways.

Discovery of 3-(1H-indol-3-yl)-4-[2-(4-methylpiperazin-1-yl)quinazolin-4-yl]pyrrole-2,5-dione (AEB071), a potent and selective inhibitor of protein kinase C isotypes

A series of novel maleimide-based inhibitors of protein kinase C (PKC) were designed, synthesized, and evaluated. AEB071 (1) was found to be a potent, selective inhibitor of classical and novel PKC isotypes. 1 is a highly efficient immunomodulator, acting via inhibition of early T cell activation. The binding mode of maleimides to PKCs, proposed by molecular modeling, was confirmed by X-ray analysis of 1 bound in the active site of PKCalpha.

Structure-activity relationship and pharmacokinetic studies of sotrastaurin (AEB071), a promising novel medicine for prevention of graft rejection and treatment of psoriasis.

Protein kinase C (PKC) isotypes have emerged as key targets for the blockade of early T-cell activation. Herein, we report on the structure-activity relationship and the detailed physicochemical and in vivo pharmacokinetic properties of sotrastaurin (AEB071, 1), a novel maleimide-based PKC inhibitor currently in phase II clinical trials. Most notably, the preferred uptake of sotrastaurin into lymphoid tissues is an important feature, which is likely to contribute to its in vivo efficacy.

2,6-Naphthyridines as potent and selective inhibitors of the novel protein kinase C isozymes.

The present study describes a novel series of ATP-competitive PKC inhibitors based on the 2,6-naphthyridine template. Example compounds potently inhibit the novel Protein Kinase C (PKC) isotypes δ, ε, η, θ (in particular PKCε/η, and display a 10-100-fold selectivity over the classical PKC isotypes. The prototype compound 11 was found to inhibit PKCθ-dependent pathways in vitro and in vivo. In vitro, a-CD3/a-CD28-induced lymphocyte proliferation could be effectively blocked in 10% rat whole blood. In mice, 11 dose-dependently inhibited Staphylococcus aureus enterotoxin B-triggered IL-2 serum levels after oral dosing.

Indolyl-naphthyl-maleimides as potent and selective inhibitors of protein kinase C-α/β

The indolyl-naphthyl maleimide 7 is a potent inhibitor of the classical PKC isotypes α,β and shows excellent selectivity over the novel PKC isotypes δ,ε,η,θ and other kinases belonging to the AGC family. The SAR around 7 as well as the physico-chemical characteristics of selected derivatives and their activity in T and B cell activation and proliferation assays are discussed.