Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The circadian timing system and the cell division cycle are frequently deregulated in cancer. The therapeutic relevance of the reciprocal interactions between both biological rhythms was investigated using Seliciclib, a cyclin-dependent kinase (CDK) inhibitor (CDKI). Mice bearing Glasgow osteosarcoma received Seliciclib (300 mg/kg/d orally) or vehicle for 5 days at Zeitgeber time (ZT) 3, 11, or 19. On day 6, tumor mRNA 24-hour expression patterns were determined for clock genes (Per2, Rev-erbalpha, and Bmal1) and clock-controlled cell cycle genes (c-Myc, Wee1, cyclin B1, and CDK1) with quantitative reverse transcription-PCR. Affinity chromatography on immobilized Seliciclib identified CDK1/CDK2 and extracellular signal-regulated kinase (ERK) 1/ERK2, CDK7/CDK9, and casein kinase CK1epsilon as Seliciclib targets, which respectively regulate cell cycle, transcription, and circadian clock in Glasgow osteosarcoma. Seliciclib reduced tumor growth by 55% following dosing at ZT3 or ZT11 and by 35% at ZT19 compared with controls (P < 0.001). Tolerability was also best at ZT3. Mean transcriptional activity of Rev-erbalpha, Per2, and Bmal1 was arrhythmic in the tumors of untreated mice. Seliciclib induced rhythmic clock gene expression patterns with physiologic phase relations only after ZT3 dosing. c-Myc and Wee1 mRNAs displayed synchronous circadian rhythms in the tumors of control mice receiving vehicle only but not in those of mice given the drug. Seliciclib further enhanced Wee1 expression irrespective of dosing time, an effect that reinforced G(2)-M gating. Seliciclib also inhibited CK1epsilon, which determines circadian period length. The coordination of clock gene expression patterns in tumor cells was associated with best antitumor activity of Seliciclib. The circadian clock and its upstream regulators represent relevant targets for CDKIs.
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PMID:Improved tumor control through circadian clock induction by Seliciclib, a cyclin-dependent kinase inhibitor. 1710 8

The cyclin-dependent protein kinases are key regulators of cell cycle progression. Aberrant expression or altered activity of distinct cyclin-dependent kinase (CDK) complexes results in escape of cells from cell cycle control, leading to unrestricted cell proliferation. CDK inhibitors have the potential to induce cell cycle arrest and apoptosis in cancer cells, and identifying small-molecule CDK inhibitors has been a major focus in cancer research. Several CDK inhibitors are entering the clinic, the most recent being selective CDK2 and CDK4 inhibitors. We have identified a diaminopyrimidine compound, R547, which is a potent and selective ATP-competitive CDK inhibitor. In cell-free assays, R547 effectively inhibited CDK1/cyclin B, CDK2/cyclin E, and CDK4/cyclin D1 (K(i) = 1-3 nmol/L) and was inactive (K(i) > 5,000 nmol/L) against a panel of >120 unrelated kinases. In vitro, R547 effectively inhibited the proliferation of tumor cell lines independent of multidrug resistant status, histologic type, retinoblastoma protein, or p53 status, with IC(50)s </= 0.60 mumol/L. The growth-inhibitory activity is characterized by a cell cycle block at G(1) and G(2) phases and induction of apoptosis. R547 reduced phosphorylation of the cellular retinoblastoma protein at specific CDK phosphorylation sites at the same concentrations that induced cell cycle arrest, suggesting a potential pharmacodynamic marker for clinical use. In vivo, R547 showed antitumor activity in all of the models tested to date, including six human tumor xenografts and an orthotopic syngeneic rat model. R547 was efficacious with daily oral dosing as well as with once weekly i.v. dosing in established human tumor models and at the targeted efficacious exposures inhibited phosphorylation of the retinoblastoma protein in the tumors. The selective kinase inhibition profile and the preclinical antitumor activity of R547 suggest that it may be promising for development for use in the treatment of solid tumors. R547 is currently being evaluated in phase I clinical trials.
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PMID:In vitro and in vivo activity of R547: a potent and selective cyclin-dependent kinase inhibitor currently in phase I clinical trials. 1712 11

A 2-phenyl-4-quinolone (2-PQ) derivative, 2-(3-fluorophenyl)-6-methoxyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (YJC-1), was synthesized in our laboratory. In this study, we delineated the growth-inhibitory effect of YJC-1 in human lung carcinoma A549 cells. YJC-1 inhibited cell growth with an IC(50) value of about 4.8 microM via microtubule polymerization, causing growth arrest in the mitotic phase. Immunoblotting analysis revealed a dramatic induction of cyclin-dependent kinase (CDK) inhibitor p21(Cip1/Waf1) and down-regulation of Cdc25C phosphatase to inhibit the protein expression of cyclin B1 and CDK1. We also found that YJC-1 induced a profound time-dependent elevation in p21(Cip1/Waf1) gene expression in comparison with the negative control. In vivo, we also found that YJC-1 significantly suppressed tumor growth in mice inoculated with A549 cells. These findings suggest that YJC-1 can suppress A549 cell growth via mitotic phase arrest.
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PMID:2-(3-Fluorophenyl)-6-methoxyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (YJC-1) induces mitotic phase arrest in A549 cells. 1722 2

Antiandrogens are initially effective in controlling prostate cancer (CaP), the second most common cancer in men, but resistance, associated with the loss of androgen-regulated cell cycle control, is a major problem. At present there is no effective treatment for androgen-independent prostate cancer (AIPC). Cellular proliferation is driven by cyclin-dependent kinases (CDKs) with kinase inhibitors (for example, p27) applying the breaks. We present the first investigation of the therapeutic potential of CDK inhibitors, using the guanine-based CDK inhibitor NU2058 (CDK2 IC(50)=17 microM, CDK1 IC(50)=26 microM), in comparison with the antiandrogen bicalutamide (Casodex) in AIPC cells. A panel of AIPC cells was found to be resistant to Casodex-induced growth inhibition, but with the exception of PC3 (GI(50)=38 microM) and CWR22Rv1 (GI(50)=46 microM) showed similar sensitivity to NU2058 (GI(50)=10-17 microM) compared to androgen-sensitive LNCaP cells (GI(50)=15 microM). In LNCaP cells and their Casodex-resistant derivative, LNCaP-cdxR, growth inhibition by NU2058 was accompanied by a concentration-dependent increase in p27 levels, reduced CDK2 activity and pRb phosphorylation, a decrease in early gene expression and G1 cell cycle phase arrest in both cell lines. In response to Casodex, there were similar observations in LNCaP cells (GI(50)=6+/-3 microM Casodex) but not in LNCaP-cdxR cells (GI(50)=24+/-5 microM Casodex).
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PMID:Therapeutic potential of CDK inhibitor NU2058 in androgen-independent prostate cancer. 1759 54

The c-MET receptor can be overexpressed, amplified, or mutated in solid tumours including small cell lung cancer (SCLC). In c-MET-overexpressing SCLC cell line NCI-H69, hepatocyte growth factor (HGF) dramatically induced c-MET phosphorylation at phosphoepitopes pY1230/1234/1235 (catalytic tyrosine kinase), pY1003 (juxtamembrane), and also of paxillin at pY31 (CRKL-binding site). We utilised a global proteomics phosphoantibody array approach to identify further c-MET/HGF signal transduction intermediates in SCLC. Strong HGF induction of specific phosphorylation sites in phosphoproteins involved in c-MET/HGF signal transduction was detected, namely adducin-alpha [S724], adducin-gamma [S662], CREB [S133], ERK1 [T185/Y187], ERK1/2 [T202/Y204], ERK2 [T185/Y187], MAPKK (MEK) 1/2 [S221/S225], MAPKK (MEK) 3/6 [S189/S207], RB [S612], RB1 [S780], JNK [T183/Y185], STAT3 [S727], focal adhesion kinase (FAK) [Y576/S722/S910], p38alpha-MAPK [T180/Y182], and AKT1[S473] and [T308]. Conversely, inhibition of phosphorylation by HGF in protein kinase C (PKC), protein kinase R (PKR), and also CDK1 was identified. Phosphoantibody-based immunohistochemical analysis of SCLC tumour tissue and microarray established the role of c-MET in SCLC biology. This supports a role of c-MET activation in tumour invasive front in the tumour progression and invasion involving FAK and AKT downstream. The c-MET serves as an attractive therapeutic target in SCLC, as shown through small interfering RNA (siRNA) and selective prototype c-MET inhibitor SU11274, inhibiting the phosphorylation of c-MET itself and its downstream molecules such as AKT, S6 kinase, and ERK1/2. Investigation of mechanisms of invasion and, ultimately, metastasis in SCLC would be very useful with these signal transduction molecules.
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PMID:Downstream signalling and specific inhibition of c-MET/HGF pathway in small cell lung cancer: implications for tumour invasion. 1766 9

1. Mammalian eggs are arrested at metaphase of their second meiotic division when ovulated and remain arrested until fertilized. The sperm delivers into the egg phospholipase C (PLC) zeta, which triggers a series of Ca(2+) spikes lasting several hours. The Ca(2+) spikes provide the necessary and sufficient trigger for all the events of fertilization, including exit from metaphase II arrest and extrusion of cortical granules that block the entry of other sperm. 2. The oscillatory Ca(2+) signal switches on calmodulin-dependent protein kinase II (CaMKII), which phosphorylates the egg-specific protein Emi2, earmarking it for degradation. To remain metaphase II arrested, eggs must maintain high levels of maturation-promoting factor (MPF) activity, a heterodimer of CDK1 and cyclin B1. Emi2 prevents loss of MPF by blocking cyclin B1 degradation, a process that is achieved by inhibiting the activity of the anaphase-promoting complex/cyclosome. However, CaMKII is not the primary initiator in the extrusion of cortical granules. 3. Ca(2+) spiking is also observed in mitosis of one-cell embryos, probably because PLCzeta contains a nuclear localization signal and so is released into the cytoplasm following nuclear envelope breakdown. The function of these mitotic Ca(2+) spikes remains obscure, although they are not absolutely required for passage through mitosis. 4. Intriguingly, the pattern of Ca(2+) spikes observed at fertilization has an effect on both pre- and postimplantation development in a manner that is independent of their ability to activate eggs. This suggests that the Ca(2+) spikes set in train at fertilization are having effects on processes initiated in the newly fertilized egg but whose influences are only observed several cell divisions later. The nature of the signals remains little explored, but their importance is clear and so warrants further investigation.
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PMID:Intracellular calcium in the fertilization and development of mammalian eggs. 1771 98

CCR7 and its ligands, CCL19 and CCL21, are responsible for directing the migration of T cells and dendritic cells into lymph nodes, where these cells play an important role in the initiation of the immune response. Recently, we have shown that systemic application of CCL19-IgG is able to inhibit the colocalization of T cells and dendritic cells within secondary lymphoid organs, resulting in pronounced immunosuppression with reduced allograft rejection after organ transplantation. In this study, we demonstrate that the application of sustained high concentrations of either soluble or immobilized CCL19 and CCL21 elicits an inhibitory program in T cells. We show that these ligands specifically interfere with cell proliferation and IL-2 secretion of CCR7(+) cells. This could be demonstrated for human and murine T cells and was valid for both CD4(+) and CD8(+) T cells. In contrast, CCL19 had no inhibitory effect on T cells from CCR7 knockout mice, but CCR7(-/-) T cells showed a proliferative response upon TCR-stimulation similar to that of CCL19-treated wild-type cells. Furthermore, the inhibition of proliferation is associated with delayed degradation of the cyclin-dependent kinase (CDK) inhibitor p27(Kip1) and the down-regulation of CDK1. This shows that CCR7 signaling is linked to cell cycle control and that sustained engagement of CCR7, either by high concentrations of soluble ligands or by high density of immobilized ligands, is capable of inducing cell cycle arrest in TCR-stimulated cells. Thus, CCR7, a chemokine receptor that has been demonstrated to play an essential role during activation of the immune response, is also competent to directly inhibit T cell proliferation.
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PMID:CCR7 signaling inhibits T cell proliferation. 1798 37

Reversine (RV) is the synthetic purine identified from a protein kinase-based screen of purine mimetics and it has been shown to induce muscle myoblast differentiation into progenitor cells that can be further converted into other cell lineages. Since protein kinases play a pivotal role in cell cycle control, we hypothesize that RV might affect the proliferation of cancer cells. Herein we report that RV inhibited growth of cultured human tumor cells, respectively, PC-3, HeLa, CWR22Rv1, and DU-145 cells, and induced accumulation of polyploidal cells with > or =4N DNA content. However, RV was without effect on growth of normal prostate epithelial cells. RV-treated PC-3 cells showed enlarged nuclei and an estimated 100-fold increase in cell size. Moreover, PC-3 cells treated with RV for 2-4 days were accompanied by a marked increase in the expression of p21(WAF1), a modest elevation in the levels of cyclin D3 and CDK6 and concomitantly, also a substantial reduction in cyclin B and CDK1. These results suggest that RV may induce polyploidy and increase in cell size by up-regulating p21(WAF1) and cyclin D3/CDK6, while simultaneously suppressing the expression of cyclin B and CDK1.
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PMID:The 2,6-disubstituted purine reversine induces growth arrest and polyploidy in human cancer cells. 1798 54

To generate new scaffold candidates as highly selective and potent cyclin-dependent kinase (CDK) inhibitors, structure-based drug screening was performed utilizing 3D pharmacophore conformations of known potent inhibitors. As a result, CR229 (6-bromo-2,3,4,9-tetrahydro-carbolin-1-one) was generated as the hit-compound. A computational docking study using the X-ray crystallographic structure of CDK2 in complex with CR229 was evaluated. This predicted binding mode study of CR229 with CDK2 demonstrated that CR229 interacted effectively with the Leu83 and Glu81 residues in the ATP-binding pocket of CDK2 for the possible hydrogen bond formation. Furthermore, biochemical studies on inhibitory effects of CR229 on various kinases in the human cervical cancer HeLa cells demonstrated that CR229 was a potent inhibitor of CDK2 (IC50: 3 microM), CDK1 (IC50: 4.9 microM), and CDK4 (IC50: 3 microM), yet had much less inhibitory effect (IC50: >20 microM) on other kinases, such as casein kinase 2-1 (CK2- alpha1), protein kinase A (PKA), and protein kinase C (PKC). Accordingly, these data demonstrate that CR229 is a potent CDK inhibitor with anticancer efficacy.
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PMID:Discovery of cyclin-dependent kinase inhibitor, CR229, using structurebased drug screening. 1815 91

Cyclin B1 is a key regulatory protein controlling cell cycle progression in vertebrates. Cyclin B1 binds CDK1, a cyclin-dependent kinase catalytic subunit, forming a complex that orchestrates mitosis through phosphorylation of key proteins. Cyclin B1 regulates both the activation of CDK1 and its subcellular localization, which may be critical for substrate selection. Here, we demonstrate that cyclin B1 is concentrated on the outer plate of the kinetochore during prometaphase. This localization requires the cyclin box region of the protein. Cyclin B1 is displaced from individual kinetochores to the spindle poles by microtubule attachment to the kinetochores, and this displacement is dependent on the dynein/dynactin complex. Depletion of cyclin B1 by vector-based siRNA causes inefficient attachment between kinetochores and microtubules, and chromosome alignment defects, and delays the onset of anaphase. We conclude that cyclin B1 accumulates at kinetochores during prometaphase, where it contributes to the correct attachment of microtubules to kinetochores and efficient alignment of the chromosomes, most likely through localized phosphorylation of specific substrates by cyclin B1-CDK1. Cyclin B1 is then transported from each kinetochore as microtubule attachment is completed, and this relocalization may redirect the activity of cyclin B1-CDK1 and contribute to inactivation of the spindle assembly checkpoint.
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PMID:Cyclin B1 is localized to unattached kinetochores and contributes to efficient microtubule attachment and proper chromosome alignment during mitosis. 1824 86


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