The Protein Kinase C Inhibitor Aeb071 (Sotrastaurin) Modulates Migration and Superoxide Anion Production by Human Neutrophils In Vitro

Abstract

We examined the effect ofthe protein kinase C-selective inhibitorAEB071 (sotrastaurin) on neutrophil functions in vitro. Pre-incubation with AEB071 at concentrations similar to those reached during in vivo therapy significantly reduced cell capacity to migrate toward three different chemo-attractants and to produce superoxide anions (02-) in response to phorbol myristate acetate (PMA) or to N-formylmethionyl-Ieucyl-phenylalanine (tMLP). AEB071 also significantly inhibited the 02-overproduction induced by tMLP in neutrophils primed with tumor necrosis factor alpha (TNF-a) or granulocyte/ macrophage-colony stimulating factor (GM-CSF). This inhibition was not linked to tMLP-receptor down-regulation since the drug had no effect on either tMLP-receptors or tMLP-induced CDllb membrane expression. When the activity of AEB071 was compared to that of the conventional protein kinase C (PKC) inhibitor Go6850 (which, like sotrastaurin, inhibits classical and novel PKC isoforms), G06976 (an inhibitor of a and p PKC isoforms) and rottlerin (a prevailing () PKC isoform inhibitor), AEB071 at an equimolar concentration of 3 JIM (close to the maximum drug concentration reached in patients treated with AEB071) caused significantly more inhibition on both chemotactic response and superoxide production. These in vitro findings suggest that neutrophils may offer a cellular target for AEB071 activity in vivo.Protein kinase C (PKC) is a family of multifunctional serine/threonine kinases which have regulatory roles in all aspects of eukaryotic cell function (1, 2). This family comprises at least ten isoforms divided into three groups on the basis of molecular structure and biochemical properties: classical PKC isoforms (a,~I,~II and y), novel PKC (8, E, eand TJ) and atypical PKC (~and t / A).PKC are expressed in various cell types and regulate many different cellular processes. Only recently in vitro studies and particularly in vivo studies of PKC isoform-selective knockout mice have clarified the unique function of each isotype in the immune system. Specifically, PKC a and PKC efunction in T-cell signaling and survival (3-5), PKC~and PKC 8 in B-cell signaling and survival (6-8) and PKC E in macrophage and dendritic cell activation (9).In animal models PKC 8 is involved in induction oftolerance (8) and PKC~in B-cell antigen receptor function (7). Thus, PKC isoforms in T and B cells have been proposed as attractive therapeutic targets for transplantation, inflammatory and autoimmune

A PKC-MARCKS-PI3K regulatory module links Ca2+ and PIP3 signals at the leading edge of polarized macrophages

“…The effects of each modulator on leading edge area was determined by imaging the functional leading edge regions of robust, highly polarized macrophages exhibiting actively ruffling, leading edge membranes ( Fig 2A ). As previously observed in the literature [ 14 , 51 , 60 – 63 ], Fig 3 shows that the activators PDGF and ATP trigger leading edge expansion, while the inhibitors wortmannin, EGTA and Go6976 yield leading edge contraction. Within error, at 5.5 min after addition, the activators yield the same extent of steady state leading edge expansion, and the inhibitors yield the same extent of contraction.…”

Docetaxel Facilitates Endothelial Dysfunction through Oxidative Stress via Modulation of Protein Kinase C Beta: The Protective Effects of Sotrastaurin

“…Some of the pharmacological effects of sotrastaurin have been identified. Sotrastaurin increases Foxp3 levels, which reduces IFNc release and ROS formation after proinflammatory stimulation (Capsoni et al, 2012;He et al, 2014). This study was the first to demonstrate that sotrastaurin protects endothelial cells from DTX-induced PKCb phosphorylation, NAPDH oxidase activation, ROS production, and cell death (Fig.…”

Misoprostol Inhibits Equine Neutrophil Adhesion, Migration, and Respiratory Burst in an In Vitro Model of Inflammation

“…Together, these data suggest that misoprostol likely inhibits ROS production in IC and LPS-stimulated neutrophils through cAMP-activated PKA. In contrast, PMA stimulates ROS production through direct activation of PKC ( 47 , 48 ). Therefore, this pathway is generally thought to be insensitive to cAMP-elevating agents ( 42 , 45 ).…”