scholarly journals KRAS G13D sensitivity to neurofibromin-mediated GTP hydrolysis

2019 ◽  
Vol 116 (44) ◽  
pp. 22122-22131 ◽  
Author(s):  
Dana Rabara ◽  
Timothy H. Tran ◽  
Srisathiyanarayanan Dharmaiah ◽  
Robert M. Stephens ◽  
Frank McCormick ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Growth Factor Receptor ◽  
Egfr Inhibitors ◽  
Mitogen Activated Protein Kinase ◽  
Structural Basis ◽  
Colorectal Cancers ◽  
Dependent Manner ◽  
Gtp Hydrolysis ◽  
Promote Tumor Growth ◽  
Mitogen Activated Protein

KRAS mutations occur in ∼35% of colorectal cancers and promote tumor growth by constitutively activating the mitogen-activated protein kinase (MAPK) pathway. KRAS mutations at codons 12, 13, or 61 are thought to prevent GAP protein-stimulated GTP hydrolysis and render KRAS-mutated colorectal cancers unresponsive to epidermal growth factor receptor (EGFR) inhibitors. We report here that KRAS G13-mutated cancer cells are frequently comutated with NF1 GAP but NF1 is rarely mutated in cancers with KRAS codon 12 or 61 mutations. Neurofibromin protein (encoded by the NF1 gene) hydrolyzes GTP directly in complex with KRAS G13D, and KRAS G13D-mutated cells can respond to EGFR inhibitors in a neurofibromin-dependent manner. Structures of the wild type and G13D mutant of KRAS in complex with neurofibromin (RasGAP domain) provide the structural basis for neurofibromin-mediated GTP hydrolysis. These results reveal that KRAS G13D is responsive to neurofibromin-stimulated hydrolysis and suggest that a subset of KRAS G13-mutated colorectal cancers that are neurofibromin-competent may respond to EGFR therapies.

scholarly journals BRAF Mutation in Colorectal Cancers: From Prognostic Marker to Targetable Mutation

Cancers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3236
Author(s):  
Izuma Nakayama ◽  
Toru Hirota ◽  
Eiji Shinozaki
Keyword(s):  
Braf Mutation ◽  
Mapk Pathway ◽  
Treatment Strategies ◽  
Growth Factor Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Colorectal Cancers ◽  
Strongly Correlated ◽  
Recent Success ◽  
Molecular Features ◽  
Mitogen Activated Protein

The Raf murine sarcoma viral oncogene homolog B (BRAF) mutation is detected in 8–12% of metastatic colorectal cancers (mCRCs) and is strongly correlated with poor prognosis. The recent success of the BEACON CRC study and the development of targeted therapy have led to the determination of BRAF-mutated mCRCs as an independent category. For nearly two decades, a growing body of evidence has established the significance of the BRAF mutation in the development of CRC. Herein, we overview both basic and clinical data relevant to BRAF-mutated CRC, mainly focusing on the development of treatment strategies. This review is organized into eight sections, including clinicopathological features, molecular features, prognosis, the predictive value of anti-epidermal growth factor receptor (EGFR) therapy, resistant mechanisms for BRAF-targeting treatment, the heterogeneity of the BRAF mutation, future perspectives, and conclusions. A characterization of the canonical mitogen-activated protein kinase (MAPK) pathway is essential for controlling this malignancy, and the optimal combination of multiple interventions for treatments remains a point of debate.

scholarly journals Regulation of EphB2 activation and cell repulsion by feedback control of the MAPK pathway

2008 ◽  
Vol 183 (5) ◽  
pp. 933-947 ◽  
Author(s):  
Alexei Poliakov ◽  
Maria L. Cotrina ◽  
Andrea Pasini ◽  
David G. Wilkinson
Keyword(s):  
Feedback Loop ◽  
Fibroblast Growth Factor Receptor ◽  
Mapk Pathway ◽  
Tyrosine Phosphatase ◽  
Growth Factor Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Eph Receptor ◽  
Mitogen Activated Protein ◽  
Mediate Cell ◽  
Cell Repulsion

In this study, we investigated whether the ability of Eph receptor signaling to mediate cell repulsion is antagonized by fibroblast growth factor receptor (FGFR) activation that can promote cell invasion. We find that activation of FGFR1 in EphB2-expressing cells prevents segregation, repulsion, and collapse responses to ephrinB1 ligand. FGFR1 activation leads to increased phosphorylation of unstimulated EphB2, which we show is caused by down-regulation of the leukocyte common antigen–related tyrosine phosphatase receptor that dephosphorylates EphB2. In addition, FGFR1 signaling inhibits further phosphorylation of EphB2 upon stimulation with ephrinB1, and we show that this involves a requirement for the mitogen-activated protein kinase (MAPK) pathway. In the absence of activated FGFR1, EphB2 activates the MAPK pathway, which in turn promotes EphB2 activation in a positive feedback loop. However, after FGFR1 activation, the induction of Sprouty genes inhibits the MAPK pathway downstream of EphB2 and decreases cell repulsion and segregation. These findings reveal a novel feedback loop that promotes EphB2 activation and cell repulsion that is blocked by transcriptional targets of FGFR1.

scholarly journals Phosphorylation of High-Mobility Group Protein A2 by Nek2 Kinase during the First Meiotic Division in Mouse Spermatocytes

2004 ◽  
Vol 15 (3) ◽  
pp. 1224-1232 ◽  
Author(s):  
Silvia Di Agostino ◽  
Monica Fedele ◽  
Paolo Chieffi ◽  
Alfredo Fusco ◽  
Pellegrino Rossi ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Chromatin Condensation ◽  
High Mobility ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Correct Process ◽  
High Mobility Group Protein ◽  
Mitogen Activated Protein ◽  
Pachytene Spermatocytes

The mitogen-activated protein kinase (MAPK) pathway is required for maintaining the chromatin condensed during the two meiotic divisions and to avoid a second round of DNA duplication. However, molecular targets of the MAPK pathway on chromatin have not yet been identified. Here, we show that the architectural chromatin protein HMGA2 is highly expressed in male meiotic cells. Furthermore, Nek2, a serine-threonine kinase activated by the MAPK pathway in mouse pachytene spermatocytes, directly interacts with HMGA2 in vitro and in mouse spermatocytes. The interaction does not depend on the activity of Nek2 and seems constitutive. On progression from pachytene to metaphase, Nek2 is activated and HMGA2 is phosphorylated in an MAPK-dependent manner. We also show that Nek2 phosphorylates in vitro HMGA2 and that this phosphorylation decreases the affinity of HMGA2 for DNA and might favor its release from the chromatin. Indeed, we find that most HMGA2 associates with chromatin in mouse pachytene spermatocytes, whereas it is excluded from the chromatin upon the G2/M progression. Because hmga2-/- mice are sterile and show a dramatic impairment of spermatogenesis, it is possible that the functional interaction between HMGA2 and Nek2 plays a crucial role in the correct process of chromatin condensation in meiosis.

scholarly journals Flavonoid Naringenin: A Potential Immunomodulator forChlamydia trachomatisInflammation

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Abebayehu N. Yilma ◽  
Shree R. Singh ◽  
Lisa Morici ◽  
Vida A. Dennis
Keyword(s):  
Inflammatory Mediators ◽  
Mapk Pathway ◽  
Costimulatory Molecule ◽  
Asymptomatic Infection ◽  
Mitogen Activated Protein Kinase ◽  
Gene Transcript ◽  
Dependent Manner ◽  
Sexually Transmitted ◽  
Gm Csf ◽  
Mitogen Activated Protein

Chlamydia trachomatis, the agent of bacterial sexually transmitted infections, can manifest itself as either acute cervicitis, pelvic inflammatory disease, or a chronic asymptomatic infection. Inflammation induced byC. trachomatiscontributes greatly to the pathogenesis of disease. Here we evaluated the anti-inflammatory capacity of naringenin, a polyphenolic compound, to modulate inflammatory mediators produced by mouse J774 macrophages infected with liveC. trachomatis. Infected macrophages produced a broad spectrum of inflammatory cytokines (GM-CSF, TNF, IL-1β, IL-1α, IL-6, IL-12p70, and IL-10) and chemokines (CCL4, CCL5, CXCL1, CXCL5, and CXCL10) which were downregulated by naringenin in a dose-dependent manner. Enhanced protein and mRNA gene transcript expressions of TLR2 and TLR4 in addition to the CD86 costimulatory molecule on infected macrophages were modulated by naringenin. Pathway-specific inhibition studies disclosed that p38 mitogen-activated-protein kinase (MAPK) is involved in the production of inflammatory mediators by infected macrophages. Notably, naringenin inhibited the ability ofC. trachomatisto phosphorylate p38 in macrophages, suggesting a potential mechanism of its attenuation of concomitantly produced inflammatory mediators. Our data demonstrates that naringenin is an immunomodulator of inflammation triggered byC. trachomatis, which possibly may be mediated upstream by modulation of TLR2, TLR4, and CD86 receptors on infected macrophages and downstream via the p38 MAPK pathway.

scholarly journals Decreased Phosphorylated ERK 1/2 in Individuals with Autism

2019 ◽  
Author(s):  
Anthony Russo ◽  
Albert Mensah ◽  
Judith Bowman
Keyword(s):  
Intracellular Signaling ◽  
Mapk Pathway ◽  
Growth Factor Receptor ◽  
Autism Spectrum ◽  
Mitogen Activated Protein Kinase ◽  
Signaling Cascades ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Epidermal Growth ◽  
Spectrum Disorders

Autism spectrum disorders (ASDs) are complex, highly heritable neurodevelopmental disorders affecting ∼1 in 60-100 children. The extracellular signal-regulated kinases, ERK1 and ERK2, are central elements of one of the most prominent intracellular signaling cascades, the mitogen activated protein kinase (MAPK) pathway. They are genetically linked to ASDs and other syndromes typified by intellectual disability. In this study, we measured the concentration of phosphorylated (activated) ERK 1 and 2. We present evidence that ERK is decreased in individuals with autism, and that ERK levels are associated with decreased Epidermal Growth Factor Receptor (EGFR).

scholarly journals Paclitaxel Inhibits Synoviocyte Migration and Inflammatory Mediator Production in Rheumatoid Arthritis

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaochen Chen ◽  
Haofeng Lin ◽  
Jinyang Chen ◽  
Lisheng Wu ◽  
Junqing Zhu ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Inflammatory Mediator ◽  
Mapk Pathway ◽  
Bone Destruction ◽  
New Drugs ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Inflammatory Mediator Production ◽  
Tnf Α ◽  
Mitogen Activated Protein

Activated fibroblast-like synoviocytes (FLSs) play a crucial role in the pathogenesis and progression of rheumatoid arthritis (RA). It is urgent to develop new drugs that can effectively inhibit the abnormal activation of RA-FLS. In our study, the RA-FLS cell line, MH7A, and mice with collagen-induced arthritis (CIA) were used to evaluate the effect of paclitaxel (PTX). Based on the results, PTX inhibited the migration of RA-FLS in a dose-dependent manner and significantly reduced the spontaneous expression of IL-6, IL-8, and RANKL mRNA and TNF-α-induced transcription of the IL-1β, IL-8, MMP-8, and MMP-9 genes. However, PTX had no significant effect on apoptosis in RA-FLS. Mechanistic studies revealed that PTX significantly inhibited the TNF-α-induced phosphorylation of ERK1/2 and JNK in the mitogen-activated protein kinase (MAPK) pathway and suppressed the TNF-α-induced activation of AKT, p70S6K, 4EBP1, and HIF-1α in the AKT/mTOR pathway. Moreover, PTX alleviated synovitis and bone destruction in CIA mice. In conclusion, PTX inhibits the migration and inflammatory mediator production of RA-FLS by targeting the MAPK and AKT/mTOR signaling pathways, which provides an experimental basis for the potential application in the treatment of RA.

LPA is a novel lipid regulator of mesangial cell hexokinase activity and HKII isoform expression

2002 ◽  
Vol 283 (2) ◽  
pp. F271-F279 ◽  
Author(s):  
Platina E. Coy ◽  
Navin Taneja ◽  
Iris Lee ◽  
Claudie Hecquet ◽  
Jane M. Bryson ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Mesangial Cell ◽  
Mesangial Cells ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Glomerular Injury ◽  
Mitogen Activated Protein ◽  
Extracellular Lipid ◽  
Cell Mitogen

The prototypical extracellular phospholipid mediator, lysophosphatidic acid (LPA), exhibits growth factor-like properties and represents an important survival factor in serum. This potent mesangial cell mitogen is increased in conditions associated with glomerular injury. It is also a known activator of the classic mitogen-activated protein kinase (MAPK) pathway, which plays an important role in the regulation of mesangial cell hexokinase (HK) activity. To better understand the mechanisms coupling metabolism to injury, we examined the ability of LPA to regulate HK activity and expression in cultured murine mesangial cells. LPA increased total HK activity in a concentration- and time-dependent manner, with maximal increases of >50% observed within 12 h of exposure to LPA concentrations ≥25 μM (apparent ED50 2 μM). These effects were associated with increased extracellular signal-regulated kinase (ERK) activity and were prevented by the pharmacological inhibition of either MAPK/ERK kinase or protein kinase C (PKC). Increased HK activity was also associated with increased glucose (Glc) utilization and lactate accumulation, as well as selectively increased HKII isoform abundance. The ability of exogenous LPA to increase HK activity was both Ca2+independent and pertussis toxin insensitive and was mimicked by LPA-generating phospholipase A2. We conclude that LPA constitutes a novel lipid regulator of mesangial cell HK activity and Glc metabolism. This regulation requires sequential activation of both Ca2+-independent PKC and the classic MAPK pathway and culminates in increased HKII abundance. These previously unrecognized metabolic consequences of LPA stimulation have both physiological and pathophysiological implications. They also suggest a novel mechanism whereby metabolism may be coupled to cellular injury via extracellular lipid mediators.

scholarly journals Autophagic Cell Death byPoncirus trifoliataRafin., a Traditional Oriental Medicine, in Human Oral Cancer HSC-4 Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Hye-Yeon Han ◽  
Bong-Soo Park ◽  
Guem San Lee ◽  
Seung-Hwa Jeong ◽  
Hyungwoo Kim ◽  
...  
Keyword(s):  
Oral Cancer ◽  
Therapeutic Potential ◽  
Mapk Pathway ◽  
Annexin V ◽  
Poncirus Trifoliata ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Anticancer Properties ◽  
Mitogen Activated Protein ◽  
Oral Cancer Cells

Poncirus trifoliataRafin. has long been used as anti-inflammatory and antiallergic agent to treat gastrointestinal disorders and pulmonary diseases such as indigestion, constipation, chest fullness, chest pain, bronchitis, and sputum in Korea.P. trifoliataextract has recently been reported to possess anticancer properties; however, its mechanisms of action remain unclear. In this study, its antiproliferative effects and possible mechanisms were investigated in HSC-4 cells. The methanol extract ofP. trifoliata(MEPT) significantly decreased the proliferation of HSC-4 cells (inhibitory concentration (IC)50= 142.7 μg/mL) in a dose-dependent manner. While there were no significant changes observed upon cell cycle analysis and ANNEXIN V and 7-AAD double staining in the MEPT-treated groups, the intensity of acidic vesicular organelle (AVO) staining and microtubule-associated protein 1 light chain (LC) 3-II protein expression increased in response to MEPT treatment. Furthermore, 3-methyladenine (3-MA, autophagy inhibitor) effectively blocked the MEPT-induced cytotoxicity of HSC-4 cells and triggered the activation of p38 and extracellular signal-regulated kinases (ERK) proteins. Taken together, our results indicate that MEPT is a potent autophagy agonist in oral cancer cells with antitumor therapeutic potential that acts through the mitogen-activated protein kinase (MAPK) pathway.

scholarly journals Proliferation of Peripheral Blood-derived Endothelial Progenitor Cells from Stable Angina Subjects

2014 ◽  
Vol 6 (2) ◽  
pp. 91 ◽  
Author(s):  
Yudi Her Oktaviono ◽  
Djanggan Sargowo ◽  
Mohammad Aris Widodo ◽  
Yanni Dirgantara ◽  
Angliana Chouw ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Endothelial Progenitor Cells ◽  
Stable Angina ◽  
Peripheral Blood ◽  
Mapk Pathway ◽  
Growth Factor Receptor ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Endothelial Progenitor ◽  
Mitogen Activated Protein

BACKGROUND: A population of circulating Endothelial Progenitor Cells (EPCs) has been reported to play important role in maintaining endothelial function and integrity. Since EPCs culture is crucial and an optimized medium is currently available. Therefore we conducted a study to investigate whether stable angina subjects peripheral blood-derived EPCs could be cultured in this medium. Here, we performed study to detect EPCs characteristics and extracellular signalregulated kinase (Erk)1/2 Mitogen-Activated Protein Kinase (MAPK) pathway as possible underlying pathway for EPCs proliferation.METHODS: Peripheral blood EPCs from 8 stable angina subjects were cultured in an optimized medium with/without addition of supplement for 1 or 3 days. Then, the membrane of cultured EPCs were detected with immunofluorescence method for CD34, Vascular Endothelial Growth Factor Receptor 2 (VEGFR-2) and CD133. Colony forming unit (CFU) enumeration was performed. XTT Cell proliferation assay was performed to assess EPCs growth after 1 and 3-days culture. The western blot analysis was performed to detect possible activation of Erk1/2 MAPK.RESULTS: Number of EPCs and CFU cultured for 3 days were significantly higher than the ones cultured for 1 day (p=0.012). EPCs membrane markers from stable angina subjects were detected as well as CFUs were formed. There were significant increase of EPCs number, CFUs number and phosphorylated-Erk2 amount when the groups with and without supplement were compared (p<0.05). Meanwhile U0126, a MAPK Erk1/2 (MEK1/2) inhibitor, significantly inhibited the supplement-induced EPCs number, CFUs number and phosphorylated-Erk2 amount (p<0.05).CONCLUSION: Our results showed that ERK2 MAPK signaling pathway might play an important role in supplement-induced peripheral blood EPCs proliferation in subjects with stable angina.KEYWORDS: endothelial progenitor cell, EPC, p42, Erk2, proliferation

scholarly journals Molecular aspects of gefitinib antiproliferative and pro-apoptotic effects in PTEN-positive and PTEN-negative prostate cancer cell lines

2005 ◽  
Vol 12 (4) ◽  
pp. 983-998 ◽  
Author(s):  
C Festuccia ◽  
P Muzi ◽  
D Millimaggi ◽  
L Biordi ◽  
G L Gravina ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Growth Factor ◽  
Growth Inhibition ◽  
Kinase Inhibitor ◽  
Mapk Pathway ◽  
Growth Factor Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Growth Modulation ◽  
Mitogen Activated Protein ◽  
Phosphoinositide 3 Kinase

To date, no effective therapeutic treatment allows abrogation of the progression of prostate cancer (PCa) to more invasive forms. One of the major targets for the therapy in PCa can be epidermal growth factor receptor (EGFR), which signals via the phosphoinositide 3′-kinase (PI3K)/Akt and mitogen-activated protein kinase (MAPK) pathways, among others. Despite multiple reports of overexpression in PCa, the reliance on activated EGFR and its downstream signalling to the PI3K and/or MAPK/extracellular signal-regulated kinase (ERK) pathways has not been fully elucidated. We reported that the EGFR-selective tyrosine kinase inhibitor gefitinib (ZD1839; Iressa) is able to induce growth inhibition, G1 arrest and apoptosis in PCa cells and that its effectiveness is associated primarily with phosphatase and tensin homologue deleted from chromosome 10 (PTEN) expression (and thus Akt activity). In fact PTEN-negative PCa cells are slowly sensitive to gefitinib treatment, because this molecule is unable to downregulate PI3K/Akt activity. PI3K inhibition, by LY294002 or after PTEN transfection, restores EGFR-stimulated Akt signalling and sensitizes the cells to pro-apoptotic action of gefitinib. The MAPK pathway seems to be involved primarily on cell-growth modulation because dual blockade of EGFR and ERK1/2 phosphorylation potentiates growth inhibition (both not cell apoptosis) in PTEN-positive PCa cells and reduced EGF-mediated growth in PTEN-negative cells. Thus the effectiveness of gefitinib requires growth factor receptor-stimulated PI3K/Akt and MAPK signalling to be intact and functional. The loss of the PTEN activity leads to uncoupling of this signalling pathway, determining a partial gefitinib resistance. Moreover, gefitinib sensitivity may be maintained in these cells through its inhibitory potential in MAPK/ERK pathway activity, modulating proliferative EGFR-triggered events. Therefore, our data suggest that the inhibition of EGFR signalling can result in a significant growth reduction and in increased apoptosis in EGFR-overexpressing PCa cells with different modalities, which are regulated by PTEN status, and this may have relevance in the clinical setting of PCa.

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