scholarly journals BRAF Inhibitors in Thyroid Cancer: Clinical Impact, Mechanisms of Resistance and Future Perspectives

Cancers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1388 ◽  
Author(s):  
Fabiana Crispo ◽  
Tiziana Notarangelo ◽  
Michele Pietrafesa ◽  
Giacomo Lettini ◽  
Giovanni Storto ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Mapk Pathway ◽  
Single Agent ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Human Thyroid ◽  
Braf Inhibitors ◽  
Thyroid Carcinomas ◽  
Viral Oncogene ◽  
Viral Oncogene Homolog

The Kirsten rat sarcoma viral oncogene homolog (RAS)/v-raf-1 murine leukemia viral oncogene homolog 1 (RAF)/mitogen-activated protein kinase 1 (MAPK) signaling cascade is the most important oncogenic pathway in human cancers. Tumors leading mutations in the gene encoding for v-raf murine sarcoma viral oncogene homolog B (BRAF) serine-threonine kinase are reliant on the MAPK signaling pathway for their growth and survival. Indeed, the constitutive activation of MAPK pathway results in continuous stimulation of cell proliferation, enhancement of the apoptotic threshold and induction of a migratory and metastatic phenotype. In a clinical perspective, this scenario opens to the possibility of targeting BRAF pathway for therapy. Thyroid carcinomas (TCs) bearing BRAF mutations represent approximately 29–83% of human thyroid malignancies and, differently from melanomas, are less sensitive to BRAF inhibitors and develop primary or acquired resistance due to mutational events or activation of alternative signaling pathways able to reactivate ERK signaling. In this review, we provide an overview on the current knowledge concerning the mechanisms leading to resistance to BRAF inhibitors in human thyroid carcinomas and discuss the potential therapeutic strategies, including combinations of BRAF inhibitors with other targeted agents, which might be employed to overcome drug resistance and potentiate the activity of single agent BRAF inhibitors.

scholarly journals Atypical BRAF and NRAS Mutations in Mucosal Melanoma

Cancers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1133 ◽  
Author(s):  
Nicolas Dumaz ◽  
Fanélie Jouenne ◽  
Julie Delyon ◽  
Samia Mourah ◽  
Armand Bensussan ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Mucosal Melanoma ◽  
Mitogen Activated Protein Kinase ◽  
Nras Mutation ◽  
Viral Oncogene ◽  
Mitogen Activated Protein ◽  
Murine Sarcoma ◽  
Worse Prognosis ◽  
Viral Oncogene Homolog

Primary mucosal melanomas represent a minority of melanomas, but have a significantly worse prognosis than cutaneous melanomas. A better characterization of the molecular pathogenesis of this melanoma subtype could help us understand the risk factors associated with the development of mucosal melanomas and highlight therapeutic targets. Because the Mitogen-Activated Protein Kinase (MAPK) pathway plays such a significant role in melanoma development, we explore v-raf murine sarcoma viral oncogene homolog B (BRAF) and neuroblastoma RAS viral oncogene homolog (NRAS) mutations in mucosal melanoma and compare them to the mutation profiles in cutaneous melanoma and other tumors with BRAF and NRAS mutations. We show that in addition to being less frequent, BRAF and NRAS mutations are different in mucosal melanoma compared to cutaneous melanomas. Strikingly, the BRAF and NRAS mutation profiles in mucosal melanoma are closer to those found in cancers such as lung cancer, suggesting that mutations in mucosal melanoma could be linked to some genotoxic agents that remain to be identified. We also show that the atypical BRAF and NRAS mutations found in mucosal melanomas have particular effects on protein activities, which could be essential for the transformation of mucosal melanocytes.

Mitogen-Activated Protein Kinase Signaling Pathway in Cutaneous Melanoma: An Updated Review

2016 ◽  
Vol 140 (11) ◽  
pp. 1290-1296 ◽  
Author(s):  
Andres Martin Acosta ◽  
ShriHari S. Kadkol
Keyword(s):  
Protein Kinase ◽  
Signaling Pathway ◽  
Cutaneous Melanoma ◽  
Mapk Signaling ◽  
Mapk Signaling Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Braf Mutations ◽  
Viral Oncogene ◽  
Mitogen Activated Protein ◽  
Viral Oncogene Homolog

The mitogen-activated protein kinase (MAPK) signaling pathway is a cascade of protein kinases that act in a sequential and predominantly linear fashion, albeit displaying some cross talk with other signaling cascades. Mutations in proteins integral to the MAPK signaling pathway are present in more than 50% of cutaneous melanomas. The most frequently mutated protein is v-raf murine sarcoma viral oncogene homolog B (BRAF), followed by neuroblastoma Ras viral oncogene homolog (NRAS). Recently, the development of targeted drugs for the treatment of BRAF-mutant melanoma has led to the widespread implementation of molecular assays for the detection of specific BRAF mutations. There have been some attempts to standardize testing of BRAF mutations, but this has not been achieved so far. Here we provide an updated review on the role of the MAPK signaling pathway in the pathogenesis of cutaneous melanoma, focusing on several different BRAF mutations and their diagnostic and therapeutic implications.

scholarly journals Cutaneous Side Effects of BRAF Inhibitors in Advanced Melanoma: Review of the Literature

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Bilgen Gençler ◽  
Müzeyyen Gönül
Keyword(s):  
Side Effects ◽  
Metastatic Melanoma ◽  
Mapk Pathway ◽  
Case Reports ◽  
Mitogen Activated Protein Kinase ◽  
Braf V600e ◽  
Braf Inhibitors ◽  
Braf Mutations ◽  
Cutaneous Side Effects ◽  
Downstream Signaling

The incidence of melanoma has recently been increasing. BRAF mutations have been found in 40–60% of melanomas. The increased activity of BRAF V600E leads to the activation of downstream signaling through the mitogen-activated protein kinase (MAPK) pathway, which plays a key role as a regulator of cell growth, differentiation, and survival. The use of BRAF inhibitors in metastatic melanoma with BRAF mutation ensures clinical improvement of the disease. Vemurafenib and dabrafenib are two selective BRAF inhibitors approved by the Food and Drug Administration (FDA). Both drugs are well tolerated and successfully used in clinical practice. However, some adverse reactions have been reported in patients in the course of treatment. Cutaneous side effects are the most common adverse events among them with a broad spectrum. Both the case reports and several original clinical trials reported cutaneous reactions during the treatment with BRAF inhibitors. In this review, the common cutaneous side effects of BRAF inhibitors in the treatment of metastatic melanoma with BRAF V600E mutation were reviewed.

scholarly journals APPL1 mediates adiponectin-stimulated p38 MAPK activation by scaffolding the TAK1-MKK3-p38 MAPK pathway

2011 ◽  
Vol 300 (1) ◽  
pp. E103-E110 ◽  
Author(s):  
Xiaoban Xin ◽  
Lijun Zhou ◽  
Caleb M. Reyes ◽  
Feng Liu ◽  
Lily Q. Dong
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Mapk Pathway ◽  
Adaptor Protein ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Scaffolding Protein ◽  
Mapk Activation ◽  
P38 Mapk Pathway ◽  
Mitogen Activated Protein

The adaptor protein APPL1 mediates the stimulatory effect of adiponectin on p38 mitogen-activated protein kinase (MAPK) signaling, yet the underlying mechanism remains unclear. Here we show that, in C2C12 cells, overexpression or suppression of APPL1 enhanced or suppressed, respectively, adiponectin-stimulated p38 MAPK upstream kinase cascade, consisting of transforming growth factor-β-activated kinase 1 (TAK1) and mitogen-activated protein kinase kinase 3 (MKK3). In vitro affinity binding and coimmunoprecipitation experiments revealed that TAK1 and MKK3 bind to different regions of APPL1, suggesting that APPL1 functions as a scaffolding protein to facilitate adiponectin-stimulated p38 MAPK activation. Interestingly, suppressing APPL1 had no effect on TNFα-stimulated p38 MAPK phosphorylation in C2C12 myotubes, indicating that the stimulatory effect of APPL1 on p38 MAPK activation is selective. Taken together, our study demonstrated that the TAK1-MKK3 cascade mediates adiponectin signaling and uncovers a scaffolding role of APPL1 in regulating the TAK1-MKK3-p38 MAPK pathway, specifically in response to adiponectin stimulation.

Sprouty proteins: antagonists of endothelial cell signaling and more

2003 ◽  
Vol 90 (10) ◽  
pp. 586-590 ◽  
Author(s):  
Miguel Cabrita ◽  
Gerhard Christofori
Keyword(s):  
Growth Factor ◽  
Mapk Pathway ◽  
Medical Science ◽  
Receptor Activation ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Dual Function ◽  
Vegf Receptor ◽  
Mapk Activation ◽  
Binding Partners

SummaryAmong many signaling pathways, receptor tyrosine kinases (RTKs) can activate the mitogen-activated protein kinase (MAPK) signaling pathway that subsequently leads to a variety of cellular changes, including proliferation, differentiation and motility. The regulation of growth factor signaling is complex, and various cell types respond differently to the same stimulus for reasons not entirely understood. The recent discovery in Drosophila of Sprouty (dSpry), an inhibitor of RTK-induced MAPK activation, provides clues to how these signals are regulated. In mammals, four orthologues of dSpry, Spry1-4, have been described, and in this review we discuss their functional characteristics. Mammalian Sprys, like dSpry, are ligand-induced feedback inhibitors of a number of growth factor receptors. In endothelial cells, upon fibroblast growth factor (FGF) receptor and vascular endothelial growth factor (VEGF) receptor activation, Sprys translocate to the plasma membrane and inhibit cell growth and proliferation. However, in epidermal growth factor (EGF)-stimulated cells, Sprys can enhance MAPK activation. In addition, Sprys have many binding partners, including different effectors of the MAPK activation pathway. The intersection point where Sprys interfere in the MAPK pathway as well as their interactions with other proteins may partly explain the dual, yet opposing roles, on growth factor-induced MAPK activation. Moreover, Sprys require tyrosine phosphorylation to interact with their binding partners, a prerequisite for their dual function. Hence, Sprys add another layer of complexity to the regulation of RTK-mediated signal transduction that begins to explain the variation in cellular responses to growth factors.This publication was partially financed by Serono Foundation for the Advancement of Medical Science.Part of this paper was originally presented at the 2nd International Workshop on New Therapeutic Targets in Vascular Biology from February 6-9, 2003 in Geneva, Switzerland.

scholarly journals An adaptive signaling network in melanoma inflammatory niches confers tolerance to MAPK signaling inhibition

2017 ◽  
Vol 214 (6) ◽  
pp. 1691-1710 ◽  
Author(s):  
Helen L. Young ◽  
Emily J. Rowling ◽  
Mattia Bugatti ◽  
Emanuele Giurisato ◽  
Nadia Luheshi ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Acquired Resistance ◽  
Drug Tolerance ◽  
Mapk Signaling ◽  
Signaling Network ◽  
Mitogen Activated Protein Kinase ◽  
Cytokine Signaling ◽  
Adaptive Responses ◽  
Mapk Inhibitors

Mitogen-activated protein kinase (MAPK) pathway antagonists induce profound clinical responses in advanced cutaneous melanoma, but complete remissions are frustrated by the development of acquired resistance. Before resistance emerges, adaptive responses establish a mutation-independent drug tolerance. Antagonizing these adaptive responses could improve drug effects, thereby thwarting the emergence of acquired resistance. In this study, we reveal that inflammatory niches consisting of tumor-associated macrophages and fibroblasts contribute to treatment tolerance through a cytokine-signaling network that involves macrophage-derived IL-1β and fibroblast-derived CXCR2 ligands. Fibroblasts require IL-1β to produce CXCR2 ligands, and loss of host IL-1R signaling in vivo reduces melanoma growth. In tumors from patients on treatment, signaling from inflammatory niches is amplified in the presence of MAPK inhibitors. Signaling from inflammatory niches counteracts combined BRAF/MEK (MAPK/extracellular signal–regulated kinase kinase) inhibitor treatment, and consequently, inhibiting IL-1R or CXCR2 signaling in vivo enhanced the efficacy of MAPK inhibitors. We conclude that melanoma inflammatory niches adapt to and confer drug tolerance toward BRAF and MEK inhibitors early during treatment.

scholarly journals MDM2 Antagonists Induce a Paradoxical Activation of Erk1/2 through a P53-Dependent Mechanism in Dedifferentiated Liposarcomas: Implications for Combinatorial Strategies

Cancers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2253
Author(s):  
Shomereeta Roy ◽  
Audrey Laroche-Clary ◽  
Stephanie Verbeke ◽  
Marie-Alix Derieppe ◽  
Antoine Italiano
Keyword(s):  
Tyrosine Kinases ◽  
Mapk Pathway ◽  
Single Agent ◽  
Immunoblot Analysis ◽  
Mek Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
Synergistic Activity ◽  
Mdm2 Gene ◽  
Mdm2 Antagonist ◽  
The Impact

The MDM2 gene is amplified in dedifferentiated liposarcoma (DDLPS). Treatment with MDM2 antagonists is a promising strategy to treat DDLPS; however, drug resistance is a major limitation when these drugs are used as a single agent. This study examined the impact of MDM2 antagonists on the mitogen-activated protein kinase (MAPK) pathway in DDLPS and investigated the potential synergistic activity of a MAPK kinase (MEK) inhibitor in combination with MDM2 antagonists. We identified a synergistic effect and identified the mechanism behind it. Combination effects of MDM2 antagonists and a MEK inhibitor were analyzed in a patient-derived xenograft mouse model and in DDLPS and leiomyosarcoma cell lines using different cell proliferation assays and immunoblot analysis. MDM2 antagonist (RG7388)-resistant IB115 [P4] cells and p53-silenced DDLPS cells were also established to understand the importance of functional p53. We found that MDM2 antagonists induced an upregulation of phosphorylated extracellular signal-regulated kinase (p-ERK) in DDLPS cells. The upregulation of p-ERK occurred due to mitochondrial translocation of p53, which resulted in increased production of reactive oxygen species, causing the activation of receptor tyrosine kinases (RTKs). Activated RTKs led to the activation of the downstream MEK/ERK signaling pathway. Treatment with a MEK inhibitor resulted in decreased expression of p-ERK, causing significant anti-tumor synergy when combined with MDM2 antagonists. Our results provide a framework for designing clinical studies of combination therapies in DDLPS patients.

scholarly journals Avβ3 Single-Stranded DNA Aptamer Attenuates Vascular Smooth Muscle Cell Proliferation and Migration via Ras-PI3K/MAPK Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Hong-Bing Wu ◽  
Zhi-Wei Wang ◽  
Feng Shi ◽  
Zong-Li Ren ◽  
Luo-Cheng Li ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Cell Cycle Progression ◽  
Mapk Pathway ◽  
Mapk Signaling ◽  
Dna Aptamer ◽  
Mitogen Activated Protein Kinase ◽  
Vsmc Proliferation ◽  
And Migration ◽  
Proliferation And Migration

Objectives. To observe the effect of avβ3 single-stranded (ss) DNA on proliferation and migration of vascular smooth muscle cells (VSMCs) and its potential mechanism. Background. Percutaneous transluminal coronary angioplasty (PTCA) is currently the preferred method for the treatment of coronary heart disease. However, vascular restenosis still occurs after PTCA treatment, severely affecting the clinical efficacy of PTCA. Integrin avβ3, which is widely expressed on various cell surfaces, plays an important role in the proliferation and migration of VSMCs. Methods. In this experiment, we used systematic evolution of ligands by exponential enrichment (SELEX) to screen out avβ3 ssDNA, which has high affinity and specificity to the avβ3 protein. MTT, Transwell, and cell scratch assays were carried out to examine the effect of avβ3 ssDNA on the proliferation and migration of VSMCs. Flow cytometry was performed to detect apoptosis and cell cycle progression. The effect of avβ3 ssDNA on the Ras-phosphatidylinositol-4,5-bisphosphate 3-kinase/mitogen-activated protein kinase (PI3K/MAPK) signaling pathway was evaluated by quantitative reverse transcription polymerase chain reaction and western blot. Results. In the present study, we found that avβ3 ssDNA significantly decreased the expression of osteopontin, focal adhesion kinase, Ras, p-PI3K, and p-MAPK at both mRNA and protein levels (P<0.05). Avβ3 ssDNA also inhibited VSMC proliferation and migration while promoting apoptosis (P<0.05), as demonstrated by the upregulation of the proapoptotic proteins Bax and active caspase 3 (P<0.05). Conclusions. The findings suggest that avβ3 ssDNA inhibited the proliferation and migration of VSMCs by suppressing the activation of Ras-PI3K/MAPK signaling.

scholarly journals miR-19 Promotes Cell Proliferation, Invasion, Migration, and EMT by Inhibiting SPRED2-mediated Autophagy in Osteosarcoma Cells

2020 ◽  
Vol 29 ◽  
pp. 096368972096246
Author(s):  
Chuhai Xie ◽  
Shengyao Liu ◽  
Boyi Wu ◽  
Yu Zhao ◽  
Binwei Chen ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Mapk Pathway ◽  
Biological Effects ◽  
Rapid Development ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Luciferase Reporter ◽  
Osteosarcoma Cells ◽  
Mesenchymal Transition ◽  
Erk Mapk

Osteosarcoma is an aggressive malignancy with rapid development and poor prognosis. microRNA-19 (miR-19) plays an important role in several biological processes. Sprouty-related EVH1 domain protein 2 (SPRED2) is a suppressor of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling to inhibit tumor development and progression by promoting autophagy. In this study, we investigated the roles of miR-19, SPRED2, and autophagy in osteosarcoma. We detected the expression of miR-19, SPRED2, epithelial–mesenchymal transition (EMT) markers, and autophagy-related proteins via quantitative real-time polymerase chain reaction or western blot. To evaluate the function of miR-19 and SPRED2, we used MTT and colony formation assays to detect cell proliferation, Transwell, and wound-healing assays to detect cell invasion and migration. Targetscan and luciferase reporter assays confirmed the relationship between SPRED2 and miR-19. The expression of miR-19 was significantly upregulated in osteosarcoma, while SPRED2 was downregulated. miR-19 inhibitor reduced cell proliferation, invasion, migration, and EMT, while its cell biological effects were partially reversed by addition of autophagy inhibitor 3-methyladenine (3-MA) or SPRED2 siRNA in osteosarcoma. SPRED2, a suppressor of ERK/MAPK pathway that is known to trigger autophagy, was identified as a direct target of miR-19. SPRED2 overexpression increased cell proliferation, invasion, migration, and EMT by promoting autophagy, and the effects could be inhibited by 3-MA. Collectively, these findings reveal an underlying mechanism for development of osteosarcoma. miR-19 was upregulated in osteosarcoma cells, and negatively regulated SPRED2, thus promoting the malignant transformation of osteosarcoma cells via inhibiting SPRED2-induced autophagy. Therefore, miR-19/SPRED2 may be a potential target for the treatment of osteosarcoma.

Achievements and Challenges of Molecular Targeted Therapy in Melanoma

2015 ◽  
pp. 177-186 ◽  
Author(s):  
Ryan Sullivan ◽  
Patricia LoRusso ◽  
Scott Boerner ◽  
Reinhard Dummer
Keyword(s):  
Tumor Suppressor ◽  
Mapk Pathway ◽  
Single Agent ◽  
Braf Inhibitor ◽  
Clinical Trial Data ◽  
Great Majority ◽  
Mek Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
Loss Of Function ◽  
Early Clinical Trial

The treatment of melanoma has been revolutionized over the past decade with the development of effective molecular and immune targeted therapies. The great majority of patients with melanoma have mutations in oncogenes that predominantly drive signaling through the mitogen activated protein kinase (MAPK) pathway. Analytic tools have been developed that can effectively stratify patients into molecular subsets based on the identification of mutations in oncogenes and/or tumor suppressor genes that drive the MAPK pathway. At the same time, potent and selective inhibitors of mediators of the MAPK pathway such as RAF, MEK, and ERK have become available. The most dramatic example is the development of single-agent inhibitors of BRAF (vemurafenib, dabrafenib, encorafenib) and MEK (trametinib, cobimetinib, binimetinib) for patients with metastatic BRAFV600-mutant melanoma, a subset that represents 40% to 50% of patients with metastatic melanoma. More recently, the elucidation of mechanisms underlying resistance to single-agent BRAF inhibitor therapy led to a second generation of trials that demonstrated the superiority of BRAF inhibitor/MEK inhibitor combinations (dabrafenib/trametinib; vemurafenib/cobimetinib) compared to single-agent BRAF inhibitors. Moving beyond BRAFV600targeting, a number of other molecular subsets—such as mutations in MEK, NRAS, and non-V600 BRAF and loss of function of the tumor suppressor neurofibromatosis 1 ( NF1)—are predicted to respond to MAPK pathway targeting by single-agent pan-RAF, MEK, or ERK inhibitors. As these strategies are being tested in clinical trials, preclinical and early clinical trial data are now emerging about which combinatorial approaches might be best for these patients.

Sign in / Sign up

Export Citation Format

Share Document