Info Rmu
Almost two decades ago, when protein kinases were only available as more or less well-characterized biochemical activities obtained following purifica tion from various tissues, there were some ideas in the pharmaceutical industry that protein kinases could represent potential oncology targets. In 1985 at Ciba-Geigy now Novartis , one medicinal chemistry project was focusing on protein kinase C PKC . PKC was believed to be involved in tumor promotion and growth modulation, due to the fact that...
Tyrosine Analogs
In an analogous vein to serine threonine protein kinases, peptide-based inhibitors of tyrosine kinases were initially prepared by substituting the phos-phorylatable tyrosine with the nonphosphorylatable phenylalanine. In general, the phenylalanine-for-tyrosine replacement generates exceedingly poor inhibitory agents Ki gt 1 mM . Several peptides containing tyrosine analogs 12-14 were reported in the 1980s, but these derivatives proved to be ineffective as inhibitors Wong and Goldberg 1984...
Info Dgx
CD45 Regulates Receptor Thresholds 2.1 The first indication that CD45 has a positive role in regulating signals mediated by antigen receptors came from the investigation of T cell lines and T cell clones that lack CD45 expression. In these contexts it was found that Fig. 1 Domain structure of the CD45 molecule. The extensive CD45 ectodomain is characterised by three fibronectin type III FN-III repeats, a cysteine-rich domain and the three alternatively spliced exons A, B and C at the...
Info Alx
In Vitro Data Supporting p38 MAPK Activation in Pulmonary Disease The infiltration of the lungs by eosinophils is a prominent feature of asthma. These bone marrow-derived granulocytes can promote airway remodeling and tissue damage through the release of cytotoxic proteins and oxygen radicals Giembycz and Lindsay 1999 . The differentiation, recruitment, and activation of these cells result from the activity of an array of cytokines and chemokines including IL-3, IL-5, and eotaxin. Data...
Info Lpi
Neamine is a poor antibiotic and is not clinically useful. However, it serves as an invaluable template for the design of new antibiotics. It has been shown that neamine is the minimal structural motif required for binding to the A-site of 16S subunit of ribosomal RNA Fourmy et al. 1996, 1998 . Hence, it is sensible, in designing new aminoglycosides, to preserve the minimum structural motif required for RNA binding and antibiotic activity, but to deviate from typical aminoglycoside structures,...
Info Leg
Chronic toxicity is associated with structural changes in the kidney. In native kidneys there is global and segmental glomerular sclerosis. Surviving glomeruli tend to be larger, indicating hyperfiltration, and proteinuria is common Myers et al. 1988 Bertani et al. 1991 . The changes are believed to be secondary to afferent arteriolar vasculopathy leading to glomerular isch-aemia and tubular atrophy. The tubular atrophy and fibrosis follow a striped pattern which begins in the medullar and...
Mnx
Fig. 8 Superposition of the three anthraquinones MNA taken as reference , MNX, and DAA in the active site of CK2. Note that the nitro group of MNA is not co-planar with the aromatic rings as in the case of MNX Fig. 8 Superposition of the three anthraquinones MNA taken as reference , MNX, and DAA in the active site of CK2. Note that the nitro group of MNA is not co-planar with the aromatic rings as in the case of MNX same side of the inhibitor interact with side chains of Asp175, Lys68, and a...
Info Wyn
Other PTPs Involved in Cancer Development One promising target reported in the PTP family is the dual phosphatase PRL-3 and its closely related homolog PRL-1. These PTPs have been shown to promote invasiveness of cancer cells in vitro, and PRL3 was also found in metastatic human liver tumors Saha et al. 2001 Zeng et al. 2003 . Thus, targeting of PRL3 may provide an excellent means to prevent the development of metastasis. SHP-1 is a SH2 domain-containing cytoplasmic PTP, and it is predominantly...
Introduction
Protein-protein interactions serve as the adhesive that drives the assembly of signaling pathways. However, this adhesive is transient in nature. Once the cell has acknowledged the environmental stimulus, signaling pathways must rapidly disassemble to restore the cell to its resting state. At first glance, agents that selectively target key protein-protein interactions would appear to serve as ideal inhibitors of cell signaling as well as potential therapeutics. First, protein-protein...
Hi 152
with various Ki values in ATP-competitive fashion with a range of Ki values. The Ki values for Rho kinase and PKC were comparatively low, 0.35 and 0.90 mM, respectively. In an isolated arterial strip stimulated with PGF2a, we determined that HA1077 inhibits the phosphorylation of the regulatory myosin light chain MLC20 , in particular the diphosphorylation step was more sensitive than the monophosphorylation reaction Seto et al. 1991 . HA1077 was an effective inhibitor of arterial contraction...
Enzyme Inhibition
Chemical compounds were tested as potential inhibitors of EGFR-TK activity in a substrate phosphorylation assay with a synthetic peptide substrate and a plasma membrane preparation derived from human A431 cells, which overexpress the EGFR. This assay first identified the anilinoquinazoline class of EGFR-TK inhibitors Ward et al. 1994 Wakeling et al. 1996 , and subsequently the candidate drug EGFR-TK inhibitor, ZD1839 Gibson et al. 1997 Barker et al. 2001 Wakeling et al. 2002 , designated...
Info Kvz
Lck and gt 1,300-fold versus Lyn . In addition, these investigators found that several of their less potent Src kinase inhibitors IC50 values 1-3 iM range exhibit even better selectivity profiles than 28. McMurray, Budde, and coworkers likewise examined the effectiveness of cyclic peptide inhibitors on the Src kinase. These investigators first examined the affinity of a series of cyclic peptide substrates for Src i.e., the ability of these substrates to block the phosphorylation of poly Glu4Tyr...
Info Xox
Human Clinical Trials and Plasma Pharmacokinetics Because of its spectrum of activity and unique mechanism of action, the Clinical Trials Evaluation Program of the United States National Cancer Institute initiated phase I clinical trials. To determine the pharmacokinetics of fos-triecin, a high-pressure liquid chromatographic method to measure fostriecin in plasma samples was developed Pillon et al. 1994 . Fostriecin is extracted from plasma samples with acetonitrile and then dichloromethane....
Info Pmx
Fig. 11 Non-peptidyl phosphorus PTP inhibitor leads ray structure of PTP1B in complex with compound 18 acid Burke et al. 1996b Ye and Burke 1996 . Based on this structure, it was hypothesized that the addition of a hydroxyl group at the 4-position of the naphthyl ring could replace a water molecule and thereby allow H-bond formation to Tyr46 and Lys120. Indeed, addition of this hydroxyl group increased the affinity twofold, i.e., structure-based design of non-peptide PTP inhibitors was born....
Oba
Fig. 5A, B Binding mode of OBA in PTP1B. A Interaction with the P-loop. B Unique interaction with Lys120, Asp181, and Tyr46 Fig. 5A, B Binding mode of OBA in PTP1B. A Interaction with the P-loop. B Unique interaction with Lys120, Asp181, and Tyr46 interaction points with the natural substrate, pTyr, and in addition showed a unique arrangement involving residues 46, 120, and 181 pdb code 1C85-Fig. 5A and B . As will be detailed below, this simple compound has served as a basic scaffold in our...
Info Wrw
Peptide-Based Inhibitors Phosphotyrosyl Mimetics The initial attempts to design selective PTP inhibitors were based on replacement of pTyr with non-hydrolyzable phosphotyrosyl mimetics in small, efficient PTP peptide substrates, thereby utilizing both the potency and selectivity provided by the amino acid residues reviewed in Burke and Lee 2003 . The next step in inhibitor design was then planned to be modification of the peptide moiety into more drug-like compounds without losing potency or...
Info Nlq
Advances in the development of antibiotics are being compromised by bacterial populations exhibiting multiple antibiotic resistance and a number of antibiotics have been rendered clinically obsolete. The development of mul-tidrug-resistant strains of bacteria creates the potential for epidemics of infections that are either untreatable or which can only be treated by one or a few antibiotics. Aminoglycosides are a class of antibiotics used in the treatment of serious infections caused by...
Info Sze
Cantharidin appears to be too toxic for use as an antitumor drug in most clinical settings. Still, the in vitro antitumor activity of cantharidin is impressive, and the observation that it stimulates the production of white blood cells by bone marrow seems worthy of further investigation. In addition, the recent syntheses of derivatives that retain inhibitory activity suggest that more selective inhibitors can be developed. Based on in vitro investigations with fostriecin and the limited data...
PDGFR as a Therapeutic Target
Translocations involving the PDGFRB gene have been identified in several myeloproliferative and myelodysplastic syndromes. The most common of these translocations, 5 12 q33 p13 , is seen in a subset of patients with CMML and results in fusion of the EVT6 TEL and PDGFRB genes Golub et al. 1994 . EVT6 is a member of the ETS family of transcription factors and contains an amino terminal domain that mediates homotypic oligomer-ization. When fused to the membrane-spanning region of PDGFRB, this...
Info Ime
Identification of Natural Substrates The Insulin Receptor-Regulating PTP The above studies with synthetic peptides have advanced our understanding of the substrate specificity of PTP domains. However, in vivo PTPs act in the context of full-length folded proteins, and hence there is a need for gaining insight into the three-dimensional structural requirements for substrate specificity. Based on the understanding of the catalytic machinery Sect. 2 , Tonks and coworkers have devised an intriguing...
Info Ufh
The identification of paullones as a family of CDK inhibitors has been followed by several unexpected findings, specifically their stronger affinity for GSK-3, and their interactions with mitochondrial MDH. This, in fact, has opened the way to alternative applications beyond the initial anti-cancer application Zaharevitz et al. 1999 , which had not been initially predicted, namely the use against neurodegenerative disorders. As CDK GSK-3 dual specificity inhibitors, paullones could be highly...
Info Fuq
Aminoglycosides and Aminoglycoside Resistance 2.1 The first aminoglycoside, streptomycin, was isolated from the soil bacterium Streptomyces griseus in 1944 Schatz et al. 1944 . Streptomycin proved to be the first successful drug against Mycobacterium tuberculosis and became widely popular in the 1940s and 1950s. The impact of streptomycin was of such significance that Selman A. Waksman was awarded the Nobel Prize in Medicine in 1952 for its discovery. While streptomycin continues to be an...
Inhibitors of Protein Kinase CK2 Structural Aspects
R. Battistutta1 S. Sarno2 G. Zanotti1 1 Chemistry Department, University of Padova, Venetian Institute of Molecular Medicine VIMM , Padova, Italy giuseppe.zanotti unipd.it 2 Biological Chemistry Department, University of Padova, Venetian Institute of Molecular Medicine VIMM , Padova, Italy 1 Protein Kinase 2 Substrate Pleiotropicity and 3 Constitutive Activity and Lack of Regulatory Mechanisms 127 4 General Structural Features of Ser Thr Protein Kinases Catalytic Domain . 128 5...
References Ixp
Abe K, Misawa M 2003 Astrocyte stellation induced by Rho kinase inhibitors in culture. Brain Res Dev Brain Res 143 99-104 Arai M, Sasaki Y, Nozawa R 1993 Inhibition by the protein kinase inhibitor HA1077 on the activation of NADPH oxidase in human neutrophils. Biochem Pharmacol Asano T, Ikegaki I, Satoh S, Suzuki Y, Shibuya M, Takayasu M, Hidaka H 1987 Mechanism of action of a novel antivasospasm drug, HA1077. J Pharmacol Exp Ther 241 1033-1040 Bito H, Furuyashiki T, Ishihara H, Shibasaki Y,...
Info Mcx
Temporal activation of PTPs is another important factor in the regulation of PTP action. Activation can be regulated at the transcriptional level, or by post-translational mechanisms such as phosphorylation on serine threonine residues Draetta and Eckstein 1997 Digilio et al. 2002 Zheng et al. 2002 , or on tyrosine residues Ostman and Bohmer 2001 Raugei et al. 2002 . Furthermore, enzymatic activity can be inhibited rapidly and reversibly by oxidation of the essential catalytic cysteine residue...
Info Qaq
One of the first members of the protein kinase superfamily ever discovered is CK2, formerly known as casein kinase 2. The first report, dated 1954 by Burnett and Kennedy, described this enzyme isolated from liver extracts along with protein kinase CK1 Burnett and Kennedy 1954 . For their experiments, the authors utilized casein as an artificial substrate, and this is the reason for the early name casein kinase 2 indeed, since casein is not a natural substrate for the enzyme, and since the real...
Discovery of Ciclosporin and Tacrolimus
Prior to the discovery of ciclosporin, there were a limited number of agents available for clinical immunosuppression Table 1 . Acute rejection was a frequent problem that could lead to graft loss and the use of drugs such as corticosteroids in high doses for a prolonged period, which led to a high incidence of complications, particularly infection. Ciclosporin proved to be an important advance because of its selective and reversible effect on T cell activation Kahan 1989 . Ciclosporin was...
Biological Validation of the CD45 Tyrosine Phosphatase as a Pharmaceutical
Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, 2 CD45 Regulates Receptor 2.1 CD45 and Lymphocyte 2.2 CD45 and Lymphocyte 2.3 CD45 and 2.4 CD45 and Mast 2.5 CD45 and Natural Killer 3 CD45 3.1 The Src Tyrosine 3.2 Other Possible CD45 4 CD45 4.1 The Exogenous Ligand 4.2 The Size Exclusion 4.3 The Cis-Cis Interaction 4.4 The Homodimerisation 5 CD45 as a Therapeutic 5.1 The Use of CD45 Monoclonal 5.2 The Use of Chemical 5.3 Other Possible Approaches to Perturbing...
Info Xdr
The discovery of the CNIs was one of the most significant advances in clinical organ transplantation. Ciclosporin improved the results of renal transplantation and transformed other types of organ transplantation from experimental to standard therapy. Both the newer agent tacrolimus and the reformulation of ciclosporin, Neoral, have advantages over the original Sandimmun formulation. The problem of nephrotoxicity remains a factor that limits the use of these drugs outside the field of...
References Fdi
Al-Ali HK, Lange T, Krahl R, Mueller C, Patzer G, Niederwieser D, Deininger MWN 2002 BCR-ABL kinase domain mutations in patients with secondary but not primary resistance to imatinib. Blood 100 Suppl 368a Apperley JF, Gardembas M, Melo JV, Russell-Jones R, Bain BJ, Baxter EJ, Chase A, Chessells JM, Colombat M, Dearden CE, Dimitrijevic S, Mahon FX, Marin D, Nikolo-va Z, Olavarria E, Silberman S, Schultheis B, Cross NC, Goldman JM 2002 Response to imatinib mesylate in patients with chronic...
H1152p
Further derivatization of fasudil led to H-1152P, with two additional methyl groups, one at the isoquinoline ring and the other at the homopiperazine ring Tanaka et al. 1998 . H-1152P inhibits Rho kinase in the low nanomolar range, with a 400-fold selectivity over PKA Sasaki et al. 2002 . Fasudil and H-1152P bind both with similar affinity to PKA in the same orientation in the adenosine pocket Fig. 4 . H-1152P, however, has only one H-bond contact to the enzyme, the one between the hinge region...
Clinical Features of CML
CML is a clonal hematopoietic stem cell disorder. It accounts for 15 -20 of all cases of leukemia with an annual incidence of 1 to 2 cases per 100,000 per year. The median age at diagnosis is between 50 and 60 years of age. Clinically, the disease progresses through distinct phases referred to as chronic or stable, accelerated, and blast. The chronic or stable phase of the disease is characterized by excess numbers of myeloid cells that differentiate normally. After an average of 4-6 years, the...
Info Lnl
Structural Requirements for Substrate Specificity In addition to information on the catalytic machinery, the first X-ray structures of PTP1B demonstrated a common binding mode of pTyr substrates 1 binding of the phosphate moiety of pTyr to the P-loop residues 214222 and Arg221, 2 hydrophobic interactions of the phenyl ring of pTyr with the active site pocket and 3 hydrogen bonds between the main chain nitrogens of the pTyr substrate pTyr and residue 1 and the side chain of Asp48 of PTP1B, and 4...
Info Hnf
In PTP1B, Met258 and Gly259 form the bottom of a cleft-like structure positioned between the second aryl phosphate binding site and the active site pocket. We have termed this region the 258 259 gateway, which allows easy access to the active site of PTP1B. In other PTPs with bulky side chains in position 258, the gateway is blocked. Using a number of analogs of the D-A-D-E-pY-L peptide and the reciprocal mutational approach we showed that residue 259 was a key determining residue in PTP1B and...
Y27632
Y-27632, a pyridine derivative, represents a chemical class distinct from the H inhibitors described above. It has a Ki of 140 nM for Rho kinase and 25 M for PKA Table 1 Ishizaki et al. 2000 and is ATP competitive, like the H inhibitors Ikenoya et al. 2002 Trauger et al. 2002 . Y-27623 is a widely used Rho kinase inhibitor and several effects could be observed in vitro and in vivo for review see Ishizaki et al. 2000 Narumiya et al. 2000 . It prevents phosphorylation of focal adhesion kinase and...
Info Pkp
Cytokine synthesis and inflammatory mediator release PGE2,iNOS Cytokine synthesis and inflammatory mediator release PGE2,iNOS Fig. 1 p38 MAPK pathways with activators and substrates were described. These kinases exhibit between 60 and 70 amino acid identity to one another. Differences have been demonstrated in the sequence and size of their activation loop as well as their responsiveness to different stimuli. Each of the MAPK sub-families has been shown to consist of multiple isoforms and...
Info Dgk
Aberrant tyrosine phosphorylation levels have been linked both to cancer and metabolic disease states. Hence, tight regulation and specificity of PTPs is required. Nature may achieve control of PTP activity by a number of different mechanisms, as exemplified in the following 1 Site-specific tyrosine phosphorylation and dephosphorylation may result from inherent substrate specificity of kinases and phosphatases. 2 The interaction between PTPs and their cognate substrates may be regulated by...
Info Mpv
Amongst the potentially therapeutic inhibitors of natural origin are the in-dolocarbazoles, such as staurosporine, and the bisindolylmaleimides. Stau-rosporine, a potent but nonselective protein kinase inhibitor, is a microbial alkaloid from Streptomyces sp. It inhibits PKA with a Ki of about 10 nM, along with many other kinases. Staurosporine is rather unselective against some kinases such as CK1 and CK2, with inhibitory kinetics in the micromolar range, a fact that has been connected to the...
Info Ptq
Ciclosporin has been investigated as a treatment for a number of other autoimmune conditions where it has not been found to have a major role either because of limited efficacy or nephrotoxicity. Ciclosporin is active against uveitis Nussenblatt et al. 1985 but because of problems with nephrotoxicity Palestine et al. 1986 Austin et al. 1989 it is usually reserved for cases which are refractory to other therapy or severe bilateral sight-threatening uveitis Walton et al. 1998 . Type 1 diabetes is...
Info Mts
Considering that the CD45 gene was cloned and its alternatively spliced forms were already recognised in the mid-1980s, the precise functions of the molecule in vivo have proved remarkably challenging to unravel. Nevertheless, the main outline of how CD45 mediates its effects is now clear. The precise molecular actions of the different CD45 isoforms remain poorly understood, and elucidation of their functions may facilitate novel rationales for therapeutic intervention. Without doubt, CD45...
Info Tyg
An understanding of the molecular interactions at the atomic level between STI571 and Abl was key to understand the binding mode between STI571 and the inactive conformation of c-Kit Manley et al. 2002 . Six hydrogen-bonding interactions between STI571 and c-Kit, which are found in the STI571-Abl structure, were suggested by homology modeling, and five of these were recently confirmed by analysis of the crystal structure of a complex between c-Kit and STI571 Jacob et al. unpublished Fig. 2 ....
Info Uji
Although numerous analogues of paullones have been synthesised, there is probably space for improvement in both efficacy and selectivity. This would be greatly guided by the co-crystallisation of paullones with a CDK or GSK-3. Hopefully paullones can be designed that are mono-specific for CDKs, GSK-3 or MDH inhibition. This will then allow us to relate the observed cellular effects of paullones to inhibition of a specific molecular target. Paullones also need to be improved with respect to...
Info Otd
The APH 3' -IIIa enzyme is composed of two lobes, a 94-residue N-terminal lobe and a larger 157-residue C-terminal lobe. The two lobes are joined by a 12-residue linker region containing a short b-strand and a-helix. The N-ter-minal lobe consists of a five-stranded antiparallel b-sheet, with an a-helix located between two b-strands and a short 310 helix preceding the first b-strand. The architecture of the N-terminal lobe of APH 30 -IIIa is similar to that observed in eukaryotic protein kinases...
Info Gir
Bringing It All Together Future Challenges During the last few years there has been significant progress in the development of PTP inhibitors. Using structure-based design approaches, several groups have shown that it is possible to synthesize highly potent and selective non-phosphorus, non-peptide inhibitors of PTP1B. However, at this point these achievements seem to have been reached at the expense of appropriate pharmacokinetic properties, including cellular uptake. Therefore, the next wave...
Ptp1b
Undeniably, PTP1B has been the most studied PTP to date as judged by the recent numerous publications and its potential impact in the diabetes field. The intense focus on PTP1B is primarily based on the observation that PTP1B is a negative regulator of insulin and leptin signal transduction Cheng et al. 2002a Cook and Unger 2002 . Indeed, PTP1B-deficient mice display both increased insulin Elchebly et al. 1999a Klaman et al. 2000b and leptin signaling Cheng et al. 2002b Zabolotny et al. 2002 ....
Info Egu
Lee et al. first reported a series of bicyclic imidazoles that inhibited both 5-lipoxygenase cyclooxygenase LO COX and inflammatory cytokines production Lee et al. 1988, 1993, 1994, 1999 . SKF 86002 was one of the first compounds that exhibited potent anti-inflammatory activity and suppression of inflammatory cytokines. In 1995, Gallagher et al. described SB 203580 and other 2,4,5-triaryl imidazoles that were used as pharmacological tools to identify p38 MAPK as the molecular target of these...
Mcq On Protein Kinase
A marked increase in the numbers of natural killer NK cells has been noted in the spleen of both CD45 exon 6 and exon 9-targeted mice. Nevertheless, the NK cells appeared to have normal cytotoxic activities and could also differentiate normally into lymphokine-activated killer cells upon culture with IL-2 Yamada et al. 1996 Martin et al. 2001 . In addition, using the exon 9-targeted mice lacking CD45 expression, some subtle defects have been noted in the development and function of NK cells and...
The Paullones A Family of Pharmacological Inhibitors of CyclinDependent Kinases
L. Meijer1 M. Leost1 O. Lozach1 S. Schmitt1 C. Kunick2 1 C.N.R.S., Cell Cycle Group and UPS-2682, Station Biologique, B.P. 74, 29682 Roscoff cedex, Bretagne, France 2 Institut f r Pharmazie, Universit t Hamburg, Bundesstra e 45, 20146 Hamburg, Germany 1.1 Protein Kinases and 1.2 Protein Phosphorylation and 1.3 Screening for Protein Kinase 2 CDKs and GSK-3 as Kinase Screening 2.1 Kinase Purification and 2.2 Pharmacological Inhibitors of CDKs and 3 Paullones as CDK and GSK-3 3.1 Discovery of 3.2...
Info Vmf
Interest in the development of protein kinase inhibitors has grown so enormously in the last decade, both in academic and industrial laboratories, that now the protein kinase family is the second most important drug target Cohen 2002 . This is mainly due to the involvement of the superfamily of protein kinases in many key functions of cell life, including cell cycle regulation, development, proliferation, signal transmission, and apoptosis. Abnormalities in the natural roles of this class of...
Effect of HA1077 on Cerebral Infarction
In the above-mentioned double-blind trial of HA1077 in patients with SAH, the brain-protective effect seen by a decrease in cerebral infarction on CT scans was most remarkable Table 3 . In experiments in rats, the effects of HA1077 on cerebral infarction were shown in the carotid occlusion model Tsuchiya et al. 1993 Satoh et al. 1999a . The effect of HA1077 on cerebral ischemia is twofold. One positive effect is an increase in collateral circulation in penumbra through dilation of the cerebral...