Potential Role of Rho-Associated Protein Kinase Inhibitors for Glaucoma Treatment

Protein kinase inhibitors, widely exploited for elucidation of the biological functions of kinases, have more recently come under active consideration as potential chemotherapeutic agents for tumour and other diseases. A brief overview is presented of diverse approaches to the design and development of selective protein kinase inhibitors, and related problems such as donor and acceptor specificities, stereochemical aspects, emerging relationships between protein, sugar and nucleoside kinases. In particular, and contrary to popular belief that ATP-competitive inhibitors cannot be selective because of the close homology of the ATP catalytic sites, numerous examples are presented of such inhibitors which are both potent and selective for a given kinase or class of kinases. Some of these are undergoing preclinical trials. Attention is also directed to the role of cellular and viral protein kinases in the life cycle of viruses, and the potential of these enzymes, especially those encoded by, and essential for replication of, a given virus as targets for antiviral chemotherapy.

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Gene expression profile of protein kinases reveals a distinctive signature in chronic lymphocytic leukemia and in vitro experiments support a role of second generation protein kinase inhibitors

Leukemia Research ◽

10.1016/j.leukres.2009.11.005 ◽

2010 ◽

Vol 34 (6) ◽

pp. 733-741 ◽

Cited By ~ 10

Author(s):

Simona Tavolaro ◽

Sabina Chiaretti ◽

Monica Messina ◽

Nadia Peragine ◽

Ilaria Del Giudice ◽

...

Keyword(s):

Gene Expression ◽

Protein Kinase ◽

Chronic Lymphocytic Leukemia ◽

Protein Kinases ◽

Kinase Inhibitors ◽

Protein Kinase Inhibitors ◽

Lymphocytic Leukemia ◽

In Vitro Experiments

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Lysophosphatidylcholine stimulates phospholipase D in human coronary endothelial cells: role of PKC

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1996.271.4.h1706 ◽

1996 ◽

Vol 271 (4) ◽

pp. H1706-H1710 ◽

Cited By ~ 7

Author(s):

D. A. Cox ◽

M. L. Cohen

Keyword(s):

Endothelial Cells ◽

Protein Kinase ◽

Phospholipase D ◽

Kinase Inhibitors ◽

Protein Kinase Inhibitors ◽

Human Coronary Artery ◽

Gf 109203X ◽

Messenger System ◽

Stimulation Of

Lysophosphatidylcholine (lyso PC) mediates multiple potentially atherogenic effects on endothelial cells, although the cellular mechanism of these effects remains unclear. Phospholipase D (PLD) has been recognized as a novel second-messenger system that may regulate cellular function. The purpose of this study was to determine the effect of lyso PC on PLD activity in human coronary artery endothelial cells (HCAEC) by measuring [3H]phosphatidylethanol production in cells labeled with [3H]myristic acid. After incubation with lyso PC (20 microM) for 40 min, PLD activity was markedly stimulated from five- to sixfold. Stimulation of PLD activity by lyso PC was concentration dependent (half-maximum effective concentration of 7.6 microM) and was not mimicked by phosphatidylcholine (20 microM). Because PLD can be regulated by protein kinases, the effect of several protein kinase inhibitors on lyso PC-stimulated PLD activity was tested. The protein kinase A inhibitor H-89 (300 nM) and the tyrosine kinase inhibitors genistein (30 microM) and tyrphostin A25 (100 microM) had no effect on the stimulation of PLD by lyso PC (20 microM). The protein kinase C (PKC) inhibitor calphostin C (10-300 nM) affected neither lyso PC (20 microM)-nor 4 beta-phorbol 12,13-dibutyrate (PDBu, 300 nM)-stimulated PLD activity, suggesting that this agent may not inhibit PKC in these cells. In contrast, the selective PKC inhibitors GF-109203X (0.3-10 microM) and chelerythrine (1-30 microM) concentration dependently inhibited lyso PC (20 microM)-stimulated PLD activity and blocked PDBu (300 nM)-stimulated PLD activity. Together, these data document that lyso PC stimulated PLD in human endothelial cells, possibly by a PKC-dependent mechanism, and provide evidence that PLD activation in human endothelium is a novel and important mechanism by which lyso PC mediates its cellular and possibly atherogenic effects.

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Abstract 483: The Signaling Pathways of Nicotine-induced ERK1/2 Phosphorylation in Rat Mesangial Cells

Hypertension ◽

10.1161/hyp.60.suppl_1.a483 ◽

2012 ◽

Vol 60 (suppl_1) ◽

Author(s):

Ping Hua ◽

Wenguang Feng ◽

Gabriel Rezonzew ◽

Phillip H Chumley ◽

Edgar A Jaimes

Keyword(s):

Protein Kinase ◽

Signaling Pathways ◽

Kinase Inhibitors ◽

Mesangial Cells ◽

Protein Kinase Inhibitors ◽

Biologically Active ◽

Calcium Calmodulin Dependent ◽

Nicotine Receptors ◽

High Concentrations

Tobacco smoking is associated with accelerated progression of chronic kidney disease of different etiologies including diabetes and hypertension. However, the mechanisms involved are not well understood. We have previously reported that nicotine, a biologically active compound present in high concentrations in tobacco, induces cell proliferation and fibronectin production in mesangial cells which are prevented by ERK1/2 inhibition (AJP’05). In these studies we determined whether rat mesangial cells (MC) express nicotine receptors and characterized the signaling pathways that lead to ERK1/2 phosphorylation in response to nicotine. MC were grown in DMEM with 15% FBS in the presence of 0.4 mg/ml G418 and starved for 24 hours in DMEM without FBS before treatment. We first demonstrated that MC are endowed with several nicotinic Ach receptor (nAChR) subunits including α2-7 and β1-4 as assessed by western blot. Treatment of rat MC with nicotine at 10 -7 M caused a time-dependent ERK1/2 phosphorylation which peaked after 10 min of stimulation( N=3). Several protein kinase inhibitors were then used to identify the upstream kinases that mediate nicotine-induced ERK1/2 phosphorylation. The calcium/calmodulin-dependent protein kinase II (CaMKII) inhibitor KN93 (10 -7 M) decreased the ERK1/2 phosphorylation level by ∼57% (0.41 of 0.95) as compared to nicotine. The PKC inhibitor Go6983 at 10 -9 M, the PKA inhibitor H89 (10 -8 M) and the EGFR inhibitor AG 1478 (10 -7 M) also inhibited ERK1/2 phosphorylation by 60% (0.38 of 0.95), 48% (0.63 of 1.20) and 68% (0.40 of 1.23) respectively as compared to nicotine. Given the role of the nicotine receptors as agonist-regulated Ca 2+ channels, we determined the effects of Ca 2+ channel blockade on nicotine induced ERK1/2 phosphorylation. Treatment of MC with the calcium channel Verapamil (10 -9 M) resulted in 33% (0.49 of 0.73) inhibition of ERK1/2 phosphorylation as compared to nicotine. In summary, we have determined in these studies that rat MC are endowed with several nAChR subunits and that ERK1/2 phosphorylation in response to nicotine requires CaMK II, PKA, PKC and EGFR. In addition, we have demonstrated that these effects require Ca 2+ consistent with the role of the nAChR as agonist-regulated Ca 2+ channels in MC.

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