scholarly journals Celecoxib as a Valuable Adjuvant in Cutaneous Melanoma Treated with Trametinib

2021 ◽  
Vol 22 (9) ◽  
pp. 4387
Author(s):  
Diana Valentina Tudor ◽  
Ioana Bâldea ◽  
Diana Elena Olteanu ◽  
Eva Fischer-Fodor ◽  
Virag Piroska ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Protein Kinase ◽  
Mapk Pathway ◽  
Human Fibroblasts ◽  
In Vitro Study ◽  
Melanoma Cells ◽  
Mitogen Activated Protein Kinase ◽  
Culture Cells ◽  
Nm Range

Background: Melanoma patients stop responding to targeted therapies mainly due to mitogen activated protein kinase (MAPK) pathway re-activation, phosphoinositide 3 kinase/the mechanistic target of rapamycin (PI3K/mTOR) pathway activation or stromal cell influence. The future of melanoma treatment lies in combinational approaches. To address this, our in vitro study evaluated if lower concentrations of Celecoxib (IC50 in nM range) could still preserve the chemopreventive effect on melanoma cells treated with trametinib. Materials and Methods: All experiments were conducted on SK-MEL-28 human melanoma cells and BJ human fibroblasts, used as co-culture. Co-culture cells were subjected to a celecoxib and trametinib drug combination for 72 h. We focused on the evaluation of cell death mechanisms, melanogenesis, angiogenesis, inflammation and resistance pathways. Results: Low-dose celecoxib significantly enhanced the melanoma response to trametinib. The therapeutic combination reduced nuclear transcription factor (NF)–kB (p < 0.0001) and caspase-8/caspase-3 activation (p < 0.0001), inhibited microphthalmia transcription factor (MITF) and tyrosinase (p < 0.05) expression and strongly down-regulated the phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) signaling pathway more significantly than the control or trametinib group (p < 0.0001). Conclusion: Low concentrations of celecoxib (IC50 in nM range) sufficed to exert antineoplastic capabilities and enhanced the therapeutic response of metastatic melanoma treated with trametinib.

Phosphorylation of Argonaute 2 at serine-387 facilitates its localization to processing bodies

2008 ◽  
Vol 413 (3) ◽  
pp. 429-436 ◽  
Author(s):  
Yan Zeng ◽  
Heidi Sankala ◽  
Xiaoxiao Zhang ◽  
Paul R. Graves
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Kinase Inhibitor ◽  
Mapk Pathway ◽  
Phosphorylation Site ◽  
Mitogen Activated Protein Kinase ◽  
Processing Bodies ◽  
Mitogen Activated Protein

Ago (Argonaute) proteins are essential effectors of RNA-mediated gene silencing. To explore potential regulatory mechanisms for Ago proteins, we examined the phosphorylation of human Ago2. We identified serine-387 as the major Ago2 phosphorylation site in vivo. Phosphorylation of Ago2 at serine-387 was significantly induced by treatment with sodium arsenite or anisomycin, and arsenite-induced phosphorylation was inhibited by a p38 MAPK (mitogen-activated protein kinase) inhibitor, but not by inhibitors of JNK (c-Jun N-terminal kinase) or MEK [MAPK/ERK (extracellular-signal-regulated kinase) kinase]. MAPKAPK2 (MAPK-activated protein kinase-2) phosphorylated bacterially expressed full-length human Ago2 at serine-387 in vitro, but not the S387A mutant. Finally, mutation of serine-387 to an alanine residue or treatment of cells with a p38 MAPK inhibitor reduced the localization of Ago2 to processing bodies. These results suggest a potential regulatory mechanism for RNA silencing acting through Ago2 serine-387 phosphorylation mediated by the p38 MAPK pathway.

scholarly journals Identification of RAS-Mitogen-Activated Protein Kinase Signaling Pathway Modulators in an ERF1 Redistribution® Screen

2006 ◽  
Vol 11 (4) ◽  
pp. 423-434 ◽  
Author(s):  
Charlotta Grånäs ◽  
Betina Kerstin Lundholt ◽  
Frosty Loechel ◽  
Hans-Christian Pedersen ◽  
Sara Petersen Bjørn ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Signaling Pathway ◽  
Kinase Inhibitors ◽  
Mapk Pathway ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
A Cell ◽  
Protein Kinase Signaling

The RAS-mitogen-activated protein kinase (MAPK) signaling pathway has a central role in regulating the proliferation and survival of both normal and tumor cells. This pathway has been 1 focus area for the development of anticancer drugs, resulting in several compounds, primarily kinase inhibitors, in clinical testing. The authors have undertaken a cell-based, high-throughput screen using a novel ERF1 Redistribution® assay to identify compounds that modulate the signaling pathway. The hit compounds were subsequently tested for activity in a functional cell proliferation assay designed to selectively detect compounds inhibiting the proliferation of MAPK pathway-dependent cancer cells. The authors report the identification of 2 cell membrane-permeable compounds that exhibit activity in the ERF1 Redistribution® assay and selectively inhibit proliferation of MAPK pathway-dependent malignant melanoma cells at similar potencies (IC50 =< 5 μM). These compounds have drug-like structures and are negative in RAF, MEK, and ERK in vitro kinase assays. Drugs belonging to these compound classes may prove useful for treating cancers caused by excessive MAPK pathway signaling. The results also show that cell-based, high-content Redistribution® screens can detect compounds with different modes of action and reveal novel targets in a pathway known to be disease relevant.

scholarly journals Transcriptional Coregulation by the Cell Integrity Mitogen-Activated Protein Kinase Slt2 and the Cell Cycle Regulator Swi4

2001 ◽  
Vol 21 (19) ◽  
pp. 6515-6528 ◽  
Author(s):  
Kristin Baetz ◽  
Jason Moffat ◽  
Jennifer Haynes ◽  
Michael Chang ◽  
Brenda Andrews
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Cell Wall ◽  
Transcription Factor ◽  
Protein Kinase ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Regulatory Subunit ◽  
Cell Integrity ◽  
Mitogen Activated Protein

ABSTRACT In Saccharomyces cerevisiae, the heterodimeric transcription factor SBF (for SCB binding factor) is composed of Swi4 and Swi6 and activates gene expression at the G1/S-phase transition of the mitotic cell cycle. Cell cycle commitment is associated not only with major alterations in gene expression but also with highly polarized cell growth; the mitogen-activated protein kinase (MAPK) Slt2 is required to maintain cell wall integrity during periods of polarized growth and cell wall stress. We describe experiments aimed at defining the regulatory pathway involving the cell cycle transcription factor SBF and Slt2-MAPK. Gene expression assays and chromatin immunoprecipitation experiments revealed Slt2-dependent recruitment of SBF to the promoters of the G1 cyclinsPCL1 and PCL2 after activation of the Slt2-MAPK pathway. We performed DNA microarray analysis and identified other genes whose expression was reduced in both SLT2and SWI4 deletion strains. Genes that are sensitive to both Slt2 and Swi4 appear to be uniquely regulated and reveal a role for Swi4, the DNA-binding component of SBF, which is independent of the regulatory subunit Swi6. Some of the Swi4- and Slt2-dependent genes do not require Swi6 for either their expression or for Swi4 localization to their promoters. Consistent with these results, we found a direct interaction between Swi4 and Slt2. Our results establish a new Slt2-dependent mode of Swi4 regulation and suggest roles for Swi4 beyond its prominent role in controlling cell cycle transcription.

Mechanisms of Resistance to Mitogen-Activated Protein Kinase Pathway Inhibition in BRAF-Mutant Melanoma

2012 ◽  
pp. 680-684 ◽  
Author(s):  
Eva M. Goetz ◽  
Levi A. Garraway
Keyword(s):  
Protein Kinase ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Mapk Pathway ◽  
Drug Binding ◽  
Mitogen Activated Protein Kinase ◽  
Braf V600e ◽  
Mechanisms Of Resistance ◽  
Mitogen Activated Protein

Overview: Anticancer drug resistance remains a crucial impediment to the care of many patients with cancer. Although the exact mechanisms of resistance may differ for each therapy, common mechanisms of resistance predominate, including drug inactivation or modification, mutation of the target protein, reduced drug accumulation, or bypass of target inhibition. With the discovery and use of targeted therapies (such as small-molecule kinase inhibitors), resistance has received renewed attention—especially in light of the dramatic responses that may emerge from such therapeutics in particular genetic or molecular contexts. Recently, the mitogen-activated protein kinase (MAPK) pathway has become exemplary in this regard, since it is activated in many different cancers. Drugs targeting RAF and MAPK kinase (MEK) are currently in clinical trials for the treatment of several types of cancer. Vemurafenib, a selective RAF kinase inhibitor recently approved for the treatment of BRAF(V600E) melanoma, shows strong efficacy initially; however, the development of resistance is nearly ubiquitous. In vitro testing and analysis of patient samples have uncovered several mechanisms of resistance to RAF inhibition. Surprisingly, mutations in the drug-binding pocket have not thus far been observed; however, other alterations at the level of RAF, as well as downstream activation of MEK and bypass of MEK/extracellular signal-regulated kinase (ERK) signaling altogether, confer resistance to vemurafenib. Looking forward, combined RAF and MEK inhibitor treatments may improve efficacy—yet we must anticipate mechanisms of resistance to this combination as well. Therefore, understanding and/or determining the mechanism of resistance are paramount to effective cancer treatment.

scholarly journals Mycosporine-like amino acids stimulate hyaluronan secretion by up-regulating hyaluronan synthase 2 via activation of the p38/MSK1/CREB/c-Fos/AP-1 axis

2020 ◽  
Vol 295 (21) ◽  
pp. 7274-7288
Author(s):  
Shuko Terazawa ◽  
Masahiko Nakano ◽  
Akio Yamamoto ◽  
Genji Imokawa
Keyword(s):  
Amino Acids ◽  
Transcription Factor ◽  
Protein Kinase ◽  
Intracellular Signaling ◽  
Binding Protein ◽  
Human Fibroblasts ◽  
Specific Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
Signaling Cascade ◽  
Mrna Levels

Hyaluronan (HA) is an extracellular matrix glycosaminoglycan that critically supports the physicochemical and mechanical properties of the skin. Here, we demonstrate that mycosporine-like amino acids (MAAs), which typically function as UV-absorbing compounds, can stimulate HA secretion from normal human fibroblasts. MAA-stimulated HA secretion was associated with significantly increased and decreased levels of mRNAs encoding HA synthase 2 (HAS2) and the HA-binding protein involved in HA depolymerization (designated HYBID), respectively. Using immunoblotting, we found that MAAs at 10 and at 25 μg/ml stimulate the phosphorylation of the mitogen-activated protein kinase (MAPK) p38, extracellular signal-regulated kinase (ERK)/c-Jun, and mitogen- and stress-activated protein kinase 1 (MSK1) (at Thr-581, Ser-360, and Ser-376, respectively) and activation of cAMP-responsive element-binding protein (CREB) and activating transcription factor 2 (ATF2), but not phosphorylation of JUN N-terminal kinase (JNK) or NF-κB (at Ser-276 or Ser-536, respectively), and increased c-Fos protein levels. Moreover, a p38-specific inhibitor, but not inhibitors of MAPK/ERK kinase (MEK), JNK, or NF-κB, significantly abrogated the increased expression of HAS2 mRNA, accompanied by significantly decreased MAA-stimulated HA secretion. These results suggested that the p38–MSK1–CREB–c-Fos–transcription factor AP-1 (AP-1) or the p38–ATF2 signaling cascade is responsible for the MAA-induced stimulation of HAS2 gene expression. Of note, siRNA-mediated ATF2 silencing failed to abrogate MAA-stimulated HAS2 expression, and c-Fos silencing abolished the increased expression of HAS2 mRNA. Our findings suggest that MAAs stimulate HA secretion by up-regulating HAS2 mRNA levels through activation of an intracellular signaling cascade consisting of p38, MSK1, CREB, c-Fos, and AP-1.

scholarly journals Ion Channels in The Pathogenesis of Endometriosis: A Cutting-Edge Point of View

2020 ◽  
Vol 21 (3) ◽  
pp. 1114 ◽  
Author(s):  
Gaetano Riemma ◽  
Antonio Simone Laganà ◽  
Antonio Schiattarella ◽  
Simone Garzon ◽  
Luigi Cobellis ◽  
...  
Keyword(s):  
Ion Channels ◽  
Protein Kinase ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Migration And Invasion ◽  
Urokinase Plasminogen Activator Receptor ◽  
Direct Role ◽  
Ectopic Endometrium

Background: Ion channels play a crucial role in many physiological processes. Several subtypes are expressed in the endometrium. Endometriosis is strictly correlated to estrogens and it is evident that expression and functionality of different ion channels are estrogen-dependent, fluctuating between the menstrual phases. However, their relationship with endometriosis is still unclear. Objective: To summarize the available literature data about the role of ion channels in the etiopathogenesis of endometriosis. Methods: A search on PubMed and Medline databases was performed from inception to November 2019. Results: Cystic fibrosis transmembrane conductance regulator (CFTR), transient receptor potentials (TRPs), aquaporins (AQPs), and chloride channel (ClC)-3 expression and activity were analyzed. CFTR expression changed during the menstrual phases and was enhanced in endometriosis samples; its overexpression promoted endometrial cell proliferation, migration, and invasion throughout nuclear factor kappa-light-chain-enhancer of activated B cells-urokinase plasminogen activator receptor (NFκB-uPAR) signaling pathway. No connection between TRPs and the pathogenesis of endometriosis was found. AQP5 activity was estrogen-increased and, through phosphatidylinositol-3-kinase and protein kinase B (PI3K/AKT), helped in vivo implantation of ectopic endometrium. In vitro, AQP9 participated in extracellular signal-regulated kinases/p38 mitogen-activated protein kinase (ERK/p38 MAPK) pathway and helped migration and invasion stimulating matrix metalloproteinase (MMP)2 and MMP9. ClC-3 was also overexpressed in ectopic endometrium and upregulated MMP9. Conclusion: Available evidence suggests a pivotal role of CFTR, AQPs, and ClC-3 in endometriosis etiopathogenesis. However, data obtained are not sufficient to establish a direct role of ion channels in the etiology of the disease. Further studies are needed to clarify this relationship.

scholarly journals PDK1 Homologs Activate the Pkc1–Mitogen-Activated Protein Kinase Pathway in Yeast

1999 ◽  
Vol 19 (12) ◽  
pp. 8344-8352 ◽  
Author(s):  
Maiko Inagaki ◽  
Tobias Schmelzle ◽  
Kyoko Yamaguchi ◽  
Kenji Irie ◽  
Michael N. Hall ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Mapk Pathway ◽  
Phosphorylation Site ◽  
Genetic Selection ◽  
Mitogen Activated Protein Kinase ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Mutant Form ◽  
Mitogen Activated Protein

ABSTRACT PDK1 (phosphoinositide-dependent kinase 1) is a mammalian growth factor-regulated serine/threonine kinase. Using a genetic selection based on a mutant form of the yeast MAP kinase kinase Ste7, we isolated a gene, PKH2, encoding a structurally and functionally conserved yeast homolog of PDK1. Yeast cells lacking bothPKH2 and PKH1, encoding another PDK1 homolog, were nonviable, indicating that Pkh1 and Pkh2 share an essential function. A temperature-sensitive mutant, pkh1D398Gpkh2, was phenotypically similar to mutants defective in the Pkc1–mitogen-activated protein kinase (MAPK) pathway. Genetic epistasis analyses, the phosphorylation of Pkc1 by Pkh2 in vitro, and reduced Pkc1 activity in the pkh1D398G pkh2mutant indicate that Pkh functions upstream of Pkc1. The Pkh2 phosphorylation site in Pkc1 (Thr-983) is part of a conserved PDK1 target motif and essential for Pkc1 function. Thus, the yeast PDK1 homologs activate Pkc1 and the Pkc1-effector MAPK pathway.

scholarly journals Combined VEGFR and MAPK pathway inhibition in angiosarcoma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michael J. Wagner ◽  
Yasmin A. Lyons ◽  
Jean H. Siedel ◽  
Robert Dood ◽  
Archana S. Nagaraja ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Mapk Pathway ◽  
Combined Treatment ◽  
Mek Inhibitor ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
In Vivo Model ◽  
Mitogen Activated Protein

AbstractAngiosarcoma is an aggressive malignancy of endothelial cells that carries a high mortality rate. Cytotoxic chemotherapy can elicit clinical responses, but the duration of response is limited. Sequencing reveals multiple mutations in angiogenesis pathways in angiosarcomas, particularly in vascular endothelial growth factor (VEGFR) and mitogen-activated protein kinase (MAPK) signaling. We aimed to determine the biological relevance of these pathways in angiosarcoma. Tissue microarray consisting of clinical formalin-fixed paraffin embedded tissue archival samples were stained for phospho- extracellular signal-regulated kinase (p-ERK) with immunohistochemistry. Angiosarcoma cell lines were treated with the mitogen-activated protein kinase kinase (MEK) inhibitor trametinib, pan-VEGFR inhibitor cediranib, or combined trametinib and cediranib and viability was assessed. Reverse phase protein array (RPPA) was performed to assess multiple oncogenic protein pathways. SVR angiosarcoma cells were grown in vivo and gene expression effects of treatment were assessed with whole exome RNA sequencing. MAPK signaling was found active in over half of clinical angiosarcoma samples. Inhibition of MAPK signaling with the MEK inhibitor trametinib decreased the viability of angiosarcoma cells. Combined inhibition of the VEGF and MAPK pathways with cediranib and trametinib had an additive effect in in vitro models, and a combinatorial effect in an in vivo model. Combined treatment led to smaller tumors than treatment with either agent alone. RNA-seq demonstrated distinct expression signatures between the trametinib treated tumors and those treated with both trametinib and cediranib. These results indicate a clinical study of combined VEGFR and MEK inhibition in angiosarcoma is warranted.

scholarly journals Ptc1, a Type 2C Ser/Thr Phosphatase, Inactivates the HOG Pathway by Dephosphorylating the Mitogen-Activated Protein Kinase Hog1

2001 ◽  
Vol 21 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Janel Warmka ◽  
Jennifer Hanneman ◽  
Ji Lee ◽  
Dipesh Amin ◽  
Irene Ota
Keyword(s):  
Protein Kinase ◽  
Osmotic Stress ◽  
Metal Ion ◽  
Mapk Pathway ◽  
Negative Regulator ◽  
Mitogen Activated Protein Kinase ◽  
Hog Pathway ◽  
Mitogen Activated Protein

ABSTRACT The HOG (high-osmolarity glycerol) mitogen-activated protein kinase (MAPK) pathway regulates the osmotic stress response in the yeast Saccharomyces cerevisiae. Three type 2C Ser/Thr phosphatases (PTCs), Ptc1, Ptc2, and Ptc3, have been isolated as negative regulators of this pathway. Previously, multicopy expression of PTC1 and PTC3 was shown to suppress lethality of the sln1Δ strain due to hyperactivation of the HOG pathway. In this work, we show thatPTC2 also suppresses sln1Δ lethality. Furthermore, the phosphatase activity of these PTCs was needed for suppression, as mutation of a conserved Asp residue, likely to coordinate a metal ion, inactivated PTCs. Further analysis of Ptc1 function in vivo showed that it inactivates the MAPK, Hog1, but not the MEK, Pbs2. In the wild type, Hog1 kinase activity increased transiently, ∼12-fold in response to osmotic stress, while overexpression of PTC1 limited activation to ∼3-fold. In contrast, overexpression of PTC1 did not inhibit phosphorylation of Hog1 Tyr in the phosphorylation lip, suggesting that Ptc1 does not act on Pbs2. Deletion of PTC1 also strongly affected Hog1, leading to high basal Hog1 activity and sustained Hog1 activity in response to osmotic stress, the latter being consistent with a role for Ptc1 in adaptation. In vitro, Ptc1 but not the metal binding site mutant, Ptc1D58N, inactivated Hog1 by dephosphorylating the phosphothreonine but not the phosphotyrosine residue in the phosphorylation lip. Consistent with its role as a negative regulator of Hog1, which accumulates in the nucleus upon activation, Ptc1 was found in both the nucleus and the cytoplasm. Thus, one function of Ptc1 is to inactivate Hog1.

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