Histamine is a mediator of inflammation in allergic disease and asthma. Stress activated protein kinases/c-jun N-terminal kinases (SAPK/JNK) are involved in asthma. This study examined the role of histamine receptors on the phosphorylation of SAPK/JNK in splenocytes. C57BL/6 mice splenocytes were treated with histamine (10(-4)M to 10(-11)M), and its selective ...

Posterior capsular opacification (PCO) is a common long-term complication of modern cataract surgery. We have shown that Zebularine, an inhibitor of DNA methylation, suppresses transforming growth factor-β (TGFβ)-induced lens epithelial cells (LECs)-myofibroblasts transdifferentiation. The purpose of this study is to evaluate the role that Zebularine plays in the inhibition of ...

Protein arginine methylation, catalyzed by protein arginine methyltransferases (PRMTs), is implicated in modulation of cellular processes including gene transcription. The role of PRMTs in the regulation of intracellular signaling pathways has remained obscure, however. We now show that PRMT1 methylates apoptosis signal-regulating kinase 1 (ASK1) at arginine residues 78 and ...

Constitutive and persistent activation of STAT3 has been implicated in the pathogenesis of many malignancies. Studies of CTCL cell lines have previously suggested that aberrant activation of STAT3 is mediated via silencing of the negative regulator SHP-1 by promoter methylation. In this study of ex vivo tumour cell populations from ...

Protein arginine methylation is important for a variety of cellular processes including transcriptional regulation, mRNA splicing, DNA repair, nuclear/cytoplasmic shuttling and various signal transduction pathways. However, the role of arginine methylation in protein biosynthesis and the extracellular signals that control arginine methylation are not fully understood. Basic fibroblast growth factor ...

Methyl CpG-binding protein-2 (MeCP2) is a transcriptional regulator that binds to methylated DNA at CpG sites and functions to silence DNA transcription. MeCP2 is subject to the phosphorylation modification at serine 421 (S421), which releases MeCP2 from DNA and thus facilitates gene expression. As a transcriptional repressor densely expressed in ...

DNA methylation plays a central role in the epigenetic regulation of gene expression during development and progression of cancer diseases. The inheritance of specific DNA methylation patterns are acquired in the early embryo and are specifically maintained after cellular replication via the DNA methyltransferase 1 (DNMT1). Recent studies have suggested ...

DNA methyltransferase 1 (DNMT1) has been shown to be phosphorylated on multiple serine and threonine residues, based on cell type and physiological conditions. Although recent studies have suggested that protein kinase C (PKC) may be involved, the individual contribution of PKC isoforms in their ability to phosphorylate DNMT1 remains unknown. ...

The three-tiered Raf-MEK-ERK kinase module is activated downstream of Ras and has been traditionally linked to cellular proliferation. Mammals have three Raf, two Mek and two Erk genes. Recently, the analysis of protein-protein interactions in the pathway has begun to provide a rationale for the redundancy within each tier. New ...

Novel indazolylpyrazolo[1,5-a]pyrimidine analogues have been prepared and found to be extremely potent type I B-Raf inhibitors. The lead compound shows good selectivity against a panel of 60 kinases, possesses a desirable pharmacokinetic profile, and demonstrates excellent in vivo antitumor efficacy in B-Raf mutant xenograft models.

Markers that could accurately predict responses to the general kinase inhibitor sorafenib are needed to better leverage its clinical applications. In this study, we examined a hypothesized role in the drug response for the growth arrest DNA damage-inducible gene 45β (GADD45β), which is commonly underexpressed in hepatocellular carcinoma (HCC) where ...

The RAS/RAF mitogen-activated protein kinase pathway (MAPK) is highly active in many tumor types including the majority of high-grade gliomas and expression of activated RAS or RAF in neural progenitor cells combined with either AKT activation or Ink4a/Arf loss leads to the development of high-grade gliomas in vivo. This strongly ...

Oncogene-induced senescence (OIS) is a potent tumor-suppressive mechanism that is thought to come at the cost of aging. The Forkhead box O (FOXO) transcription factors are regulators of life span and tumor suppression. However, whether and how FOXOs function in OIS have been unclear. Here, we show a role for ...

Raf-1 kinase inhibitor protein (RKIP) plays a pivotal role in modulating multiple signaling networks. Here we report backbone and side chain resonance assignments of uniformly( 15)N,( 13)C labeled human RKIP.

The oncogenic BRAF(V600E) mutation results in an active structural conformation characterized by greatly elevated ERK activity. However, additional cellular effects caused by subcellular action of BRAF(V600E) remain to be identified. To explore these effects, differences in the subcellular localization of wild-type and mutant BRAF in thyroid cancer were investigated. A ...

B-RAF is the most frequently mutated protein kinase in human cancers. The finding that oncogenic mutations in BRAF are common in melanoma, followed by the demonstration that these tumours are dependent on the RAF/MEK/ERK pathway, offered hope that inhibition of B-RAF kinase activity could benefit melanoma patients. Herein, we describe ...

B-RAF, a serine-threonine protein kinase, is one of the three RAF paralogs in humans. B-RAF participates in the RAS-RAF-MEK-ERK pathway, a conserved protein kinase-signalling cascade that is involved in regulating a number of critical cellular functions. Mutated B-RAF is believed to play a crucial role in the development, maintenance and ...

The RAF family of kinases are key components acting downstream of receptor tyrosine kinases and cells employ several distinct mechanisms to strictly control their activity. RAF transitions from an inactive state, where the N-terminal regulatory region binds intramolecularly to the C-terminal kinase domain, to an open state capable of executing ...

Activating mutations in B-RAF and N-RAS occur in ∼60 and ∼15% of melanomas, respectively. The most common mutation in B-RAF is V600E, which activates B-RAF and the downstream MEK-ERK1/2 pathway. Thus, B-RAF(V600E) is a viable therapeutic target. PLX4720 is a selective inhibitor of mutant B-RAF and its analog, PLX4032, is ...

In autosomal dominant polycystic kidney disease (ADPKD), aberrant proliferation of the renal epithelial cells is responsible for the formation of numerable fluid-filled cysts, massively enlarged kidneys, and progressive loss of renal function. cAMP agonists, including arginine vasopressin, accelerate cyst epithelial cell proliferation through protein kinase A activation of the B-Raf/MEK/extracellular ...

Human cytomegalovirus (HCMV) is a major pathogen in immunocompromised individuals. Here, non-toxic concentrations of the anti-cancer kinase inhibitor sorafenib were shown to inhibit replication of different HCMV strains (including a ganciclovir-resistant strain) in different cell types. In contrast to established anti-HCMV drugs, sorafenib inhibited HCMV major immediate early promoter activity ...

OBJECTIVE: Raf-1 kinase inhibitor protein has potential as a molecular determinant of tumor metastasis and may serve as a prognostic marker. The aim of this study is to analyze the correlation between Raf-1 kinase inhibitor protein expression and the clinicopathologic characteristics of papillary thyroid cancer. STUDY DESIGN: Immunohistochemical analysis. SETTING: ...

The role of JAK signaling in cell cycle transit and maintenance of genomic stability was determined in HL-60 human myeloblastic leukemia cells. We have previously reported that a pan-JAK inhibitor caused ERK-dependent endoreduplication. In the current study we find that JAK inhibition caused nuclear re-localization of RAF-1 which could be ...

To explore the prognostic values of Raf-1 kinase (Raf-1), phosphorylated mitogen extracellular kinase 1 (pMEK1), and phosphorylated extracellular signal-regulated protein kinase 1/2(pERK1/2) in hepatocellular carcinoma (HCC) patients. We assessed the expressions of Raf-1, pMEK1, and pERK1/2 in HCC using immunohistochemical techniques. The relationships between the expressions of Raf-1, pMEK1, and ...

The Ras, Raf, mitogen-activated protein kinase kinase (MEK) and extracellular signal-regulated kinase (ERK) signaling cascade is critically involved in cellular signaling with activating mutations in Ras and Raf present in many human tumors. Each constituent of this pathway is considered an important target for pharmaceutical intervention. The terminal kinase ERK ...

A-RAF, B-RAF, and C-RAF are a family of three protein-serine/threonine kinases that participate in the RAS-RAF-MEK-ERK signal transduction cascade. This cascade participates in the regulation of a large variety of processes including apoptosis, cell cycle progression, differentiation, proliferation, and transformation to the cancerous state. RAS mutations occur in 15-30% of ...

A high throughput screen identified N-aroylpyrazoline 1 as a selective inhibitor of the V600E mutant of B-Raf kinase. Parallel synthesis of acyl, aroyl, and sulfonyl derivatives led to the identification of several potent inhibitors in both enzymatic and cellular (pERK) assays such as compound 42.

V-RAF murine sarcoma viral oncogene homolog B1 (BRAF) is a serine/threonine-specific protein kinase that is mutated with high frequency in cutaneous melanoma, and many other cancers. Inhibition of mutant BRAF is an attractive therapeutic approach for the treatment of melanoma. A triarylimidazole BRAF inhibitor bearing a phenylpyrazole group (dimethyl-[2-(4-{5-[4-(1H-pyrazol-3-yl)-phenyl]-4-pyridin-4-yl-1H-imidazol-2-yl}-phenoxy)-ethyl]-amine, 1a) ...

A thiazolidine-2,4-dione derivative, 3-(2-aminoethyl)-5-(3-phenyl-propylidene)-thiazolidine-2,4-dione (2), was identified as a dual inhibitor of the Raf/MEK/ extracellular signal-regulated kinase (ERK) and the phosphatidylinositol 3-kinase (PI3K)/Akt signaling cascades. The discovered compound inhibited cell proliferation, induced early apoptosis, and arrested cells in G(0)/G(1) phase in human leukemia U937 cells. These results indicate its potential ...

The multikinase inhibitor sorafenib is the first oral agent to show activity against human hepatocellular carcinoma (HCC). Apoptosis has been shown to be induced in HCC by several agents, including sorafenib as well as by the naturally occurring K vitamins (VKs). As few nontoxic agents have activity against HCC growth, ...

PLX-4032 is a small-molecule, orally available B-Raf kinase inhibitor being developed by Plexxikon Inc and Hoffman-La Roche Ltd for the treatment of cancers harboring activating BRAF mutations. The primary focus of development is in melanoma (> 50% harbor activating BRAF mutations) with other solid tumors, such as colorectal carcinoma (> ...

IMPORTANCE OF THE FIELD: The Ras/Raf/MEK/ERK pathway is often activated by genetic alterations in upstream signaling molecules. Integral components of this pathway such as Ras and B-Raf are also activated by mutation. The Ras/Raf/MEK/ERK pathway has profound effects on proliferative, apoptotic and differentiation pathways. This pathway can often be effectively ...

Medullary thyroid carcinoma (MTC) is a multiple endocrine neoplasia type 2 syndrome caused by mutations in extracellular receptor or intracellular kinase domains of the RET proto-oncogene. Activation of the Ras/Raf/MEK/ERK pathway can lead to growth arrest by secreting leukemia inhibitory factor (LIF) in MTC cells harboring a RET receptor domain ...

Cerebral ischemia that develops after subarachnoid hemorrhage (SAH) carries high morbidity and mortality. Inflammatory mediators are involved in the development of cerebral ischemia through activation of the mitogen-activated protein kinase pathway. We hypothesized that blockade of the MAPkinase/ERK (MEK)/extracellular signal-regulated kinase (ERK) pathway upstream with a specific raf inhibitor would ...

The forkhead box transcription factor FOXD3 is a stemness factor that prevents the production of melanocyte progenitors from the developing neural crest; however, its role in human cancers is not known. Transformation of melanocytes gives rise to melanoma. In two thirds of melanomas, the serine/threonine kinase B-RAF is mutated to ...

Tumours with mutant BRAF are dependent on the RAF-MEK-ERK signalling pathway for their growth. We found that ATP-competitive RAF inhibitors inhibit ERK signalling in cells with mutant BRAF, but unexpectedly enhance signalling in cells with wild-type BRAF. Here we demonstrate the mechanistic basis for these findings. We used chemical genetic ...

Three papers in Cell and Nature now report that dimeric RAF is a plastic enzyme: blocking one ATP-binding site paradoxically stimulates the kinase activity of the other protomer. This occurs only in "primed" cells bearing activated RAS and WT RAF, explaining the selective efficacy of RAF inhibitors for RAF mutant ...

In continuation of our efforts toward hit identification and optimization for a B-Raf kinase project, we have employed a scaffold hopping strategy. The original HTS hit scaffold pyrazolo[1,5-a]pyrimidine was replaced with different thienopyrimidine and thienopyridine scaffolds to append the optimal pharmacophore moieties in order to generate novel B-raf kinase inhibitors ...

Many tumor suppressor proteins act to blunt the effects of mitogenic signaling pathways. Loss of function mutations in the merlin tumor suppressor underlie neurofibromatosis type 2 (NF2), a familial autosomal dominant cancer syndrome. Studies of Drosophila suggest that Hippo (hpo) is required for inhibition of cell proliferation mediated by dMer, ...

Achaete-scute complex-like 1 (ASCL1) is a transcription factor important in the malignant development of medullary thyroid cancer (MTC). Activation of Raf-1 signaling is associated with ASCL1 suppression and growth inhibition. Xanthohumol, a natural compound, has recently been shown to have anticancer properties. We thus hypothesized that xanthohumol would suppress growth ...

The use of the anticancer multikinase inhibitor sorafenib is associated with cardiac ischemia or infarction and an increase in hypertension. We investigated various mechanisms that might be responsible for its cardiotoxicity in a neonatal rat myocyte model. As measured by lactate dehydrogenase release, sorafenib treatment of myocytes caused dose-dependent damage ...

Sprouty (Spry) proteins have previously been suggested as negative regulators of the MAPK pathway through interaction with Raf-1. However, the molecular basis of this inhibition has not been elucidated. In this study, we used cells expressing FLAGtagged Raf-1 with point mutations at known phosphorylation sites to reveal that activation of ...

The active form of the serine/threonine kinase cRaf-1 is upregulated postmortem in the brains of Alzheimer's disease (AD) patients and in transgenic mouse models of AD pathology. The persistent activation of cRaf-1 can activate the proinflammatory factor NFkappaB and consequently, upregulate the expression of several of its downstream factors such ...

Activating mutations in NRAS and BRAF are found frequently in cutaneous melanomas. Because concurrent mutations of both BRAF and RAS are extremely rare, it is thought that transformation by RAS and BRAF occurs through a common mechanism. Also, there is evidence for a relationship of synthetic lethality between NRAS and ...

A-Raf belongs to the family of oncogenic Raf kinases that are involved in mitogenic signaling by activating the mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase (MEK)-ERK pathway. Low kinase activity of A-Raf toward MEK suggested that A-Raf might have alternative functions. Here, we show that A-Raf prevents cancer cell apoptosis ...

Activating mutations in KRAS and BRAF are found in more than 30% of all human tumours and 40% of melanoma, respectively, thus targeting this pathway could have broad therapeutic effects. Small molecule ATP-competitive RAF kinase inhibitors have potent antitumour effects on mutant BRAF(V600E) tumours but, in contrast to mitogen-activated protein ...

Activation of phosphatidylinositol-3-kinase (PI3K)-AKT and Kirsten rat sarcoma viral oncogene homologue (KRAS) can induce cellular immortalization, proliferation, and resistance to anticancer therapeutics such as epidermal growth factor receptor inhibitors or chemotherapy. This study assessed the consequences of inhibiting these two pathways in tumor cells with activation of KRAS, PI3K-AKT, or ...

Chronic exposure to solar ultraviolet (UV) light causes skin photoaging. Many studies have shown that naturally occurring phytochemicals have anti-photoaging effects, but their direct target molecule(s) and mechanism(s) remain unclear. We found that myricetin, a major flavonoid in berries and red wine, inhibited wrinkle formation in mouse skin induced by ...

Activating B-Raf mutations arise in 60% to 70% of human melanomas and are thought to play a vital role in tumorigenesis, although how this occurs remains poorly understood. Wild-type B-Raf is critical for normal mitosis of human somatic cells, suggesting that mutational activation of B-Raf might compromise mitosis. We examined ...

The Ras/Raf/MEK/ERK cascade is a highly conserved signal transduction module, whose activation results in a number of different physiological outcomes. Depending on the cell type or the stimulus used, the pathway has been implicated in proliferation, differentiation, apoptosis, and migration. Because of this wide range of activities, these kinases are ...