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)

Tumor survival, growth and metastasis depend on efficient tumor cell proliferation and tumor angiogenesis, and targeting both of these processes simultaneously could prove to be therapeutically relevant. The RAS/RAF signaling pathway is an important mediator of tumor cell proliferation, and angiogenesis and is often aberrantly activated in human tumors due to the presence of activated Ras or mutant B-Raf, or elevation of growth factor receptors. Sorafenib, which belongs chemically to a class that can be described as bis-aryl ureas, was selected for further pharmacologic characterization based on potent inhibition of Raf-1 and its favorable kinase selectivity profile. Further characterization showed that sorafenib suppresses both wild-type and V599E mutant B-Raf activity in vitro. In addition, sorafenib demonstrated significant activity against several receptor tyrosine kinases involved in neovascularization and tumor progression, including vascular-endothelial growth factor (VEGFR)-2, VEGFR-3, platelet-derived growth factor (PDGFR)-beta Flt-3, and c-KIT. Preclinically, sorafenib showed broad-spectrum antitumor activity in colon, breast and non-small-cell lung cancer xenograft models. A total of four phase I studies using oral sorafenib as a single agent have been completed, and the compound showed a favorable safety profile with mild to moderate diarrhea being the most common treatment-related adverse event. The maximum tolerated dose was 400 mg b.i.d. continuous. Single-agent phase II trials reported so far demonstrated antitumor activity of sorafenib in patients with hepatocellular carcinoma, sarcoma and renal cell cancer (RCC). Based on phase II results in RCC patients, a placebo-controlled phase III study was performed, which randomized a total of 905 patients, most of whom were treated previously. The partial response rate was 2% for sorafenib and 0% for placebo. Stable disease was observed in 78% and 55% of patients on sorafenib and placebo, respectively. Sorafenib significantly prolonged median progression-free survival (24 weeks) compared with placebo (12 weeks) in all subsets of patients evaluated. Approval of sorafenib by the U.S. Food and Drug Administration for this indication is pending. A first-line phase III study in RCC as well as phase III studies in hepatocellular carcinoma and metastatic melanoma have been initiated.
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PMID:Preclinical and clinical development of the oral multikinase inhibitor sorafenib in cancer treatment. 1647 53

Sorafenib is a small molecule inhibitor of several kinases involved in tumour proliferation and tumour angiogenesis including Raf, VEGFR and platelet derived growth factor receptor. In vivo Raf kinase inhibition has been observed in pharmacodynamic studies. Sorafenib is one of several VEGF-targeting compounds with recently demonstrated substantial anti-tumour effects in metastatic renal cell carcinoma. Delay in time to disease progression has been demonstrated in cytokine-refractory metastatic renal cell carcinoma, and further investigation is ongoing in a wide variety of tumour types. Sorafenib is well tolerated, with common toxicities including rash, diarrhoea, hand-foot skin reaction, fatigue and hypertension, when administered as the standard dose of 400 mg b.i.d.
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PMID:Sorafenib. 1650 17

Diarrhea associated with inflammatory bowel disease has been attributed to stimulated secretion of proinflammatory cytokines like IFN-gamma and TNF-alpha, which have been shown to downregulate the expression of the sodium-hydrogen exchanger-3 (NHE3) gene. In this study, we have investigated the mechanism of NHE3 gene regulation by IFN-gamma and TNF-alpha in C2BBe1 cells. In response to both IFN-gamma (30 ng/ml) and TNF-alpha (20 ng/ml), the construct containing the bp -95 to +5 region of the human NHE3 promoter, which harbors a number of cis-elements including four potential Sp1 binding sites, showed a maximum repression of 60%. Knockdown of Sp1 and Sp3 expression using small interfering RNA resulted in a significant inhibition of the NHE3 promoter activity and resistance to cytokines effects. These cytokines showed no effects on the expression of Sp1 and Sp3 mRNA and protein levels as assessed by RT-PCR and Western blot analyses, respectively. After treatment with cytokines, the binding of Sp1 and Sp3 proteins to NHE3 promoter decreased significantly, as seen by gel mobility shift assays and chromatin immunoprecipitation assays. The inhibitory effects of both cytokines on the NHE3 promoter were completely blocked by the broad-range kinase inhibitor staurosporine and the selective protein kinase A (PKA) inhibitor 8-bromoadenosine-3',5'-cyclic monophosphorothioate, Rp-isomer. The binding affinity of Sp1 and Sp3 proteins for NHE3 Sp1 probe was significantly decreased after in vitro phosphorylation of nuclear proteins by the alpha-catalytic subunit of PKA. Our data indicate that IFN-gamma and TNF-alpha may repress the NHE3 promoter activity in C2BBe1 cells by PKA-mediated phosphorylation of Sp1 and Sp3 transcription factors.
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PMID:IFN-gamma and TNF-alpha regulate human NHE3 gene expression by modulating the Sp family transcription factors in human intestinal epithelial cell line C2BBe1. 1676 Feb 59

The nucleocapsid (N) gene of the porcine epidemic diarrhea virus (PEDV) strain LJB/03 which was previously isolated in Heilongjiang province, China, was cloned, sequenced and compared with published sequences of other avian and mammalian coronavirus. The nucleotide sequence encoding the entire N gene open reading frame (ORF) of LJB/03 was 1326 bases long and encoded a protein of 441 amino acids with predicted Mr of 49 kDa. It consisted of 405 adenines (30.5%), 294 cytosines (22.1%), 329 guanines (24.8%) and 298 thymines (22.5%) residues. Sequence comparison with other PEDV strains selected from GenBank revealed that the LJB/03 N gene has a high sequence homology to those of other PEDV isolates, 97.4% with JS2004, 95.6% with chinju99, 96.6% with Br1/87, and 96.8% with CV777. The encoded protein shared 96.4% amino acid identities compared with CV777, 96.1% with Brl/87, 98% with JS2004, 96.90% with chinju99, respectively. The amino acid sequence contained seven potential protein kinase C phosphorylation sites, nine Casein kinase II phosphorylation sites, one Tyrosine kinase phosphorylation site, two cAMP- and cGMP-dependent protein kinase phosphorylation sites.
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PMID:Cloning and sequence analysis of the N gene of porcine epidemic diarrhea virus LJB/03. 1697 37

Most epithelia that express CFTR secrete fluid rich in HCO3- and poor in Cl- that is generated by a CFTR-dependent Cl- absorption and HCO3- secretion process that when aberrant leads to human diseases such as cystic fibrosis and congenital chloride diarrhoea. Epithelial Cl- absorption and HCO3- secretion require expression of CFTR and other Cl- and HCO3- transporters in the luminal membrane of the secreting cells. Recent advances in understanding this critical epithelial function revealed that the luminal Cl- and HCO3- transporters are members of the SLC26 family. Characterization of several members of the family reveals that all characterized thus far are electrogenic with an isoform specific Cl-/HCO3- transport stoichiometry. In vivo these transporters exist in a transporting complex with CFTR. The SLC26 transporters and CFTR are recruited to the complex by binding to scaffolds containing PDZ domains. Upon stimulation and PKA-dependent phosphorylation of CFTR R domain, the R domain binds to the SLC26 transporter STAS domain. Interaction of the R and STAS domains results in a marked and mutual activation of CFTR and the SLC26 transporters. The significance of this mode of regulation to epithelial Cl- absorption and HCO3- secretion is obvious.
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PMID:Regulatory interaction between CFTR and the SLC26 transporters. 1712 Jul 68

Disorganized ion transport caused by hypo- or hyperfunctioning of the cystic fibrosis transmembrane conductance regulator (CFTR) can be detrimental and may result in life-threatening diseases such as cystic fibrosis or secretory diarrhea. Thus, CFTR is controlled by elaborate positive and negative regulations for an efficient homeostasis. It has been shown that expression and activity of CFTR can be regulated either positively or negatively by PDZ (PSD-95/discs large/ZO-1) domain-based adaptors. Although a positive regulation by PDZ domain-based adaptors such as EBP50/NHERF1 is established, the mechanisms for negative regulation of the CFTR by Shank2, as well as the effects of multiple adaptor interactions, are not known. Here we demonstrate a physical and physiological competition between EBP50-CFTR and Shank2-CFTR associations and the dynamic regulation of CFTR activity by these positive and negative interactions using the surface plasmon resonance assays and consecutive patch clamp experiments. Furthermore whereas EBP50 recruits a cAMP-dependent protein kinase (PKA) complex to CFTR, Shank2 was found to be physically and functionally associated with the cyclic nucleotide phosphodiesterase PDE4D that precludes cAMP/PKA signals in epithelial cells and mouse brains. These findings strongly suggest that balanced interactions between the membrane transporter and multiple PDZ-based adaptors play a critical role in the homeostatic regulation of epithelial transport and possibly the membrane transport in other tissues.
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PMID:Dynamic regulation of cystic fibrosis transmembrane conductance regulator by competitive interactions of molecular adaptors. 1724 9

Purpose. Flavopiridol is a potent cyclin-dependent kinase (CDK) inhibitor that has preclinical activity in many tumours. This synthetic flavonoid was tested in a phase II nonrandomized, nonblinded multicentre clinical trial to determine its activity and toxicity in patients with previously untreated metastatic or locally advanced soft tissue sarcoma. Methods. A total of 18 patients with histologically confirmed nonoperable soft tissue was treated with flavopiridol administered at a dose of 50 mg/m(2) IV over 1 hour daily x3 days every 3 weeks. Results. Eighteen patients were accrued to the study over a period of 6 months. No objective responses were noted in the seventeen evaluable patients. Eight patients (47%) exhibited stable disease after 2 cycles (median duration of 4.3 months (range 1.4-6.9 months). Kaplan-Meier estimates for 3- and 6-month progression-free survivial rates were 44 percent and 22 percent, respectively. The only grade 3 toxicities were diarrhea (N = 2), nausea (N = 2), gastritis (N = 1), and fatigue (N = 1). Ninety-four percent of patients received >/= 90% of the planned dose intensity, during 55 treatment cycles. Conclusions. Flavopiridol was well tolerated at the dose and schedule used in this study, however, no objective treatment responses were seen and thus our results do not support further exploration of flavopiridol as a monotherapy at this dose and schedule in soft tissue sarcomas.
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PMID:A Phase II Study of Flavopiridol in Patients With Previously Untreated Advanced Soft Tissue Sarcoma. 1725 59

Bile acid malabsorption has been shown to be associated with diarrhea in cases such as ileal resection Crohn's disease of the ileum, and radiation enteritis. The mechanisms of bile acid-induced diarrhea are not fully understood. Although the induction of colonic chloride secretion in response to bile acids has been extensively investigated, to date the direct effect of bile acids on intestinal chloride absorption has not been well defined. Therefore, the current studies were undertaken to investigate the effect of bile acids on the apical Cl(-)/OH(-) exchange process utilizing Caco2 monolayers as an in vitro cellular model. Cl(-)/OH(-) exchange activity was measured as DIDS-sensitive pH gradient-driven (36)Cl uptake. The results are summarized as follows: (i) short-term exposure (20 min) of Caco2 cells to taurodeoxycholate (TDC; 200 microM) and glycochenodeoxycholate (GCDC; 200 microM) acids significantly inhibited apical Cl(-)/OH(-) exchange (by approximately 60-70%); (ii) the Ca(2+) chelator BAPTA-AM blocked the inhibition by TDC; (iii) the reduction in Cl(-)/OH(-) exchange by TDC was reversed by the PKC inhibitor, chelerythrine chloride; (iv) functional and inhibitor studies indicated that TDC induced inhibition of Cl(-)/OH(-) exchange was mediated via the activation of the PKC beta I isoform; (v) the effect of TDC on apical Cl(-)/OH(-) exchange was completely blocked by the PI3 kinase inhibitor LY294002 (5 microM); and (vi) the PKA inhibitor, RpcAMP, had no effect on TDC induced inhibition of Cl(-)/OH(-) exchange. In conclusion, our studies provide direct evidence for inhibition of human intestinal apical Cl(-)/OH(-) exchange activity by bile acids via Ca(2+)-, PI3 kinase-, and PKC beta I-dependent pathways in Caco2 cells.
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PMID:Taurodeoxycholate modulates apical Cl-/OH- exchange activity in Caco2 cells. 1738 13

It was reported earlier that Escherichia coli heat stable enterotoxin (STa), a major causative agent of secretory diarrhea, can also inhibit the proliferation of colon carcinoma cells with the involvement of cGMP mediated calcium influx. In the present study it is shown that E. coli STa inhibits cell proliferation in the colonic carcinoma cell line COLO-205 by the PKG-ERK44/42 mediated signaling pathway. This enterotoxin negatively regulates cell proliferation by downregulating the activity of ERK44/42(MAPK) and subsequently the activity of a transcription regulatory protein cMyc. The antiproliferative effect of STa was reversed by LY83583, a guanylate cyclase (GC) inhibitor and KT5823, a PKG inhibitor. Thus suggesting the involvement of cGMP dependent protein kinase (PKG) in the downregulation of ERK44/42 and subsequent inactivation of cMyc activity. Moreover, it has been shown that a specific ERK44/42 inhibitor, PD98059, also inhibits cMyc activation and cell proliferation, which further confirms the involvement of ERK44/42 in the activation of cMyc. It is also shown that E. coli STa significantly inhibits the vascular endothelial growth factor (VEGF, a potent angiogenic factor) expression in COLO-205 cells and also downregulates vascular cell adhesion molecule-1 (VCAM-1, a potent metastatic factor) expression on the COLO-205 cell surface. So it is reported for the first time that E. coli STa inhibits the proliferation of the colonic carcinoma cell line COLO-205 by the PKG-ERK44/42 mediated pathway and it may have a role against the development of colon carcinoma.
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PMID:Downregulation of human colon carcinoma cell (COLO-205) proliferation through PKG-MAP kinase mediated signaling cascade by E. coli heat stable enterotoxin (STa), a potent anti-angiogenic and anti-metastatic molecule. 1782 4

To clarify the mechanisms of diarrheal disease induced by Aeromonas sobria, we examined whether prostaglandin E2 (PGE2) was involved in the intestinal secretory action of A. sobria hemolysin by use of a mouse intestinal loop model. The amount of PGE2 in jejunal fluid and the fluid accumulation ratio were directly related to the dose of hemolysin. The increase over time in the level of PGE2 was similar to that of the accumulated fluid. In addition, hemolysin-induced fluid secretion and PGE2 synthesis were inhibited by the selective cyclooxygenase 2 (COX-2) inhibitor NS-398 but not the COX-1 inhibitor SC-560. Western blot analysis revealed that hemolysin increased the COX-2 protein levels but reduced the COX-1 protein levels in mouse intestinal mucosa in vivo. These results suggest that PGE2 functions as an important mediator of diarrhea caused by hemolysin and that PGE2 is produced primarily through a COX-2-dependent mechanism. Subsequently, we examined the relationship between PGE2, cyclic AMP (cAMP), and cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channels in mouse intestinal mucosa exposed to hemolysin. Hemolysin increased the levels of cAMP in the intestinal mucosa. NS-398 inhibited the increase in cAMP production, but SC-560 did not. In addition, H-89, a cAMP-dependent protein kinase A (PKA) inhibitor, and glibenclamide, a CFTR inhibitor, inhibited fluid accumulation. Taken together, these results indicate that hemolysin activates PGE2 production via COX-2 and that PGE2 stimulates cAMP production. cAMP then activates PKA, which in turn stimulates CFTR Cl- channels and finally leads to fluid accumulation in the intestines.
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PMID:Fluid secretion caused by aerolysin-like hemolysin of Aeromonas sobria in the intestines is due to stimulation of production of prostaglandin E2 via cyclooxygenase 2 by intestinal cells. 1808 11


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