scholarly journals Merkel cell polyomavirus small tumour antigen activates the p38 MAPK pathway to enhance cellular motility

2020 ◽  
Vol 477 (14) ◽  
pp. 2721-2733
Author(s):  
Samuel J. Dobson ◽  
Anthony Anene ◽  
James R. Boyne ◽  
Jamel Mankouri ◽  
Andrew Macdonald ◽  
...  
Keyword(s):  
P38 Mapk ◽  
Molecular Mechanisms ◽  
Mapk Pathway ◽  
Merkel Cell Polyomavirus ◽  
Cell Junctions ◽  
Tumour Antigen ◽  
Merkel Cell ◽  
Cellular Motility ◽  
Small Tumour ◽  
Mapk Signalling

Merkel cell carcinoma (MCC) is an aggressive skin cancer with high rates of recurrence and metastasis. Merkel cell polyomavirus (MCPyV) is associated with the majority of MCC cases. MCPyV-induced tumourigenesis is largely dependent on the expression of the small tumour antigen (ST). Recent findings implicate MCPyV ST expression in the highly metastatic nature of MCC by promoting cell motility and migration, through differential expression of cellular proteins that lead to microtubule destabilisation, filopodium formation and breakdown of cell–cell junctions. However, the molecular mechanisms which dysregulate these cellular processes are yet to be fully elucidated. Here, we demonstrate that MCPyV ST expression activates p38 MAPK signalling to drive cell migration and motility. Notably, MCPyV ST-mediated p38 MAPK signalling occurs through MKK4, as opposed to the canonical MKK3/6 signalling pathway. In addition, our results indicate that an interaction between MCPyV ST and the cellular phospatase subunit PP4C is essential for its effect on p38 MAPK signalling. These results provide novel opportunities for the treatment of metastatic MCC given the intense interest in p38 MAPK inhibitors as therapeutic agents.

scholarly journals Cellular sheddases are induced by Merkel cell polyomavirus small tumour antigen to mediate cell dissociation and invasiveness

2018 ◽  
Vol 14 (9) ◽  
pp. e1007276 ◽  
Author(s):  
Nnenna Nwogu ◽  
James R. Boyne ◽  
Samuel J. Dobson ◽  
Krzysztof Poterlowicz ◽  
G. Eric Blair ◽  
...  
Keyword(s):  
Merkel Cell Polyomavirus ◽  
Tumour Antigen ◽  
Merkel Cell ◽  
Cell Dissociation ◽  
Small Tumour ◽  
Mediate Cell

scholarly journals Size uniformity of animal cells is actively maintained by a p38 MAPK-dependent regulation of G1-length

2017 ◽  
Author(s):  
Shixuan Liu ◽  
Miriam B. Ginzberg ◽  
Nish Patel ◽  
Marc Hild ◽  
Bosco Leung ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Size ◽  
P38 Mapk ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Mapk Pathway ◽  
Small Cells ◽  
Animal Cells ◽  
Cycle Progression ◽  
Size Uniformity

AbstractAnimal cells within a tissue typically display a striking regularity in their size. To date, the molecular mechanisms that control this uniformity are still unknown. We have previously shown that size uniformity in animal cells is promoted, in part, by size-dependent regulation of G1 length. To identify the molecular mechanisms underlying this process, we performed a large-scale small molecule screen and found that the p38 MAPK pathway is involved in coordinating cell size and cell cycle progression. Small cells display higher p38 activity and spend more time in G1 than larger cells. Inhibition of p38 MAPK leads to loss of the compensatory G1 length extension in small cells, resulting in faster proliferation, smaller cell size and increased size heterogeneity. We propose a model wherein the p38 pathway responds to changes in cell size and regulates G1 exit accordingly, to increase cell size uniformity.One-sentence summaryThe p38 MAP kinase pathway coordinates cell growth and cell cycle progression by lengthening G1 in small cells, allowing them more time to grow before their next division.

scholarly journals The multi-site docking protein Grb2-associated binder 1 (Gab1) enhances interleukin-6-induced MAPK-pathway activation in an SHP2-, Grb2-, and time-dependent manner

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Hannes Bongartz ◽  
Karen Gille ◽  
Wiebke Hessenkemper ◽  
Katharina Mandel ◽  
Marc Lewitzky ◽  
...  
Keyword(s):  
Interleukin 6 ◽  
Molecular Mechanisms ◽  
Mapk Pathway ◽  
Sh2 Domain ◽  
Time Dependent ◽  
Signalling Pathways ◽  
Dependent Manner ◽  
Mapk Activation ◽  
Pathway Activation ◽  
Mapk Signalling

Abstract Background Cytokine-dependent activation of signalling pathways is tightly orchestrated. The spatiotemporal activation of signalling pathways dictates the specific physiological responses to cytokines. Dysregulated signalling accounts for neoplastic, developmental, and inflammatory diseases. Grb2-associated binder (Gab) family proteins are multi-site docking proteins, which expand cytokine-induced signal transduction in a spatial- and time-dependent manner by coordinating the recruitment of proteins involved in mitogen activated protein kinase (MAPK)/extracellular-signal regulated kinase (ERK) and phosphatidyl-inositol-3-kinase (PI3K) signalling. Interaction of Gab family proteins with these signalling proteins determines strength, duration and localization of active signalling cascades. However, the underlying molecular mechanisms of signal orchestration by Gab family proteins in IL-6-induced signalling are only scarcely understood. Methods We performed kinetic analyses of interleukin-6 (IL-6)-induced MAPK activation and analysed downstream responses. We compared signalling in wild-type cells, Gab1 knock-out cells, those reconstituted to express Gab1 mutants, and cells expressing gp130 receptors or receptor mutants. Results Interleukin-6-induced MAPK pathway activation can be sub-divided into an early Gab1-independent and a subsequent Gab1-dependent phase. Early Gab1-independent MAPK activation is critical for the subsequent initiation of Gab1-dependent amplification of MAPK pathway activation and requires binding of SH2 domain-containing phosphatase 2 (SHP2) to the interleukin-6 receptor complex. Subsequent and coordinated recruitment of Grb2 and SHP2 to Gab1 is essential for Gab1-dependent amplification of IL-6-induced late MAPK pathway activation and subsequent gene expression. Conclusions Overall, we elaborated the molecular requirements for Gab1-dependent, spatiotemporal orchestration of interleukin-6-dependent MAPK signalling. We discriminated IL-6-induced Gab1-independent, early activation of MAPK signalling and Gab1-dependent, sustained activation of MAPK signalling.

scholarly journals Bufalin Induces Mitochondria-Dependent Apoptosis in Pancreatic and Oral Cancer Cells by Downregulating hTERT Expression via Activation of the JNK/p38 Pathway

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xin Tian ◽  
Shundong Dai ◽  
Jing Sun ◽  
Shenyi Jiang ◽  
Chengguang Sui ◽  
...  
Keyword(s):  
Dna Damage ◽  
Oral Cancer ◽  
Cell Viability ◽  
Cancer Cells ◽  
P38 Mapk ◽  
Molecular Mechanisms ◽  
Mapk Pathway ◽  
Ros Production ◽  
Oral Cancer Cells ◽  
P38 Pathway

Bufalin, a digoxin-like active component of the traditional Chinese medicine Chan Su, exhibits potent antitumor activities in many human cancers. Bufalin induces mitochondria-dependent apoptosis in cancer cells, but the detailed molecular mechanisms are largely unknown. hTERT, the catalytic subunit of telomerase, protects against mitochondrial damage by binding to mitochondrial DNA and reducing mitochondrial ROS production. In the present study, we investigated the effects of bufalin on the cell viability, ROS production, DNA damage, and apoptosis of CAPAN-2 human pancreatic and CAL-27 human oral cancer cells. Bufalin reduced CAPAN-2 and CAL-27 cell viability with IC50values of 159.2 nM and 122.6 nM, respectively. The reduced cell viability was accompanied by increased ROS production, DNA damage, and apoptosis and decreased expression of hTERT. hTERT silencing in CAPAN-2 and CAL-27 cells by siRNA resulted in increased caspase-9/-3 cleavage and DNA damage and decreased cell viability. Collectively, these data suggest that bufalin downregulates hTERT to induce mitochondria-dependent apoptosis in CAPAN-2 and CAL-27 cells. Moreover, bufalin increased the phosphorylation of JNK and p38-MAPK in CAPAN-2 and CAL-27 cells, and blocking the JNK/p38-MAPK pathway using the JNK inhibitor SP600125 or the p38-MAPK inhibitor SB203580 reversed bufalin-induced hTERT downregulation. Thus, the JNK/p38 pathway is involved in bufalin-induced hTERT downregulation and subsequent induction of apoptosis by the mitochondrial pathway.

scholarly journals Molecular Mechanisms of Merkel Cell Polyomavirus Transformation and Replication

2020 ◽  
Vol 7 (1) ◽  
pp. 289-307 ◽  
Author(s):  
Wei Liu ◽  
Jianxin You
Keyword(s):  
Molecular Mechanisms ◽  
Human Tumor ◽  
Merkel Cell Polyomavirus ◽  
Merkel Cell ◽  
Virus Family ◽  
The Past ◽  
Molecular Events ◽  
Cellular Tropism ◽  
Novel Virus

Viral infection underlies a significant share of the global cancer burden. Merkel cell polyomavirus (MCPyV) is the newest member of the human oncogenic virus family. Its discovery over a decade ago marked the beginning of an exciting era in human tumor virology. Since then, significant evidence has emerged to support the etiologic role of MCPyV in Merkel cell carcinoma (MCC), an extremely lethal form of skin cancer. MCPyV infection is widespread in the general population. MCC diagnoses have tripled over the past 20 years, but effective treatments are currently lacking. In this review, we highlight recent discoveries that have shaped our understanding of MCPyV oncogenic mechanism and host cellular tropism, as well as the molecular events occurring in the viral infectious life cycle. These insights will guide future efforts in developing novel virus-targeted therapeutic strategies for treating the devastating human cancers associated with this new tumorigenic virus.

Inhibition of p38 MAPK Signalling Impairs the Homing of B Lineage ALL Cells to the Bone Marrow of NOD/SCID Mice.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1839-1839
Author(s):  
Julius Juarez ◽  
Aileen Dela Pena ◽  
Rana Baraz ◽  
Kenneth Francis Bradstock ◽  
Linda J. Bendall
Keyword(s):  
Bone Marrow ◽  
P38 Mapk ◽  
Mapk Pathway ◽  
Lymphoblastic Leukemia ◽  
Scid Mice ◽  
Minor Role ◽  
Akt Inhibitor ◽  
Mapk Signalling ◽  
B Lineage

Abstract The mechanisms regulating the migration of B lineage acute lymphoblastic leukemia (ALL) cells between the blood and bone marrow compartments remain obscure. The chemokine SDF-1 regulates the motility and proliferation of ALL cells in vitro. We have previously demonstrated that the chemotaxic response of these cells to SDF-1 requires signalling through p38 MAPK and that signalling through PI-3K and MEK/ERK pathways plays only a minor role in a subset of cases. This contrasts with normal CD34+ hematopoietic progenitors and CD34+CD19+ B cell progenitors where signalling through PI-3K is the predominant pathway required for chemotaxis. In this study we examined the requirement for SDF-1 and p38 MAPK signalling in the homing of the B lineage ALL cells to the bone marrow of NOD/SCID mice. CFSE-labelled ALL cells were pre-treated with either the specific CXCR4 antagonists AMD3100 (100μM) or TC14012 (100μM), the p38 MAPK inhibitor SB203580 (10μM), the AKT inhibitor LY294002 (6.65μM) or the MEK inhibitor PD98059 (20μM) for 0.5–1 h at 37°C. Control or inhibitor treated cells were then injected intravenously into irradiated NOD/SCID mice which were either pre-treated with control (vehicle) or the inhibitors AMD3100 (200μg/mouse), TC14012 (200μg/mouse), SB203580 (0.1 mg/mouse), the AKT inhibitor LY294002 (2 mg/mouse) or the ERK inhibitor PD98059 (0.2 mg/mouse). Homing was assessed 4 hours after the injection of cells before significant proliferation of homed cells could occur. AMD3100 and TC14012 significantly inhibited the homing of ALL cells to the bone marrow by up to 80% and 67% respectively. Inhibition of p38 MAPK also decreased the homing of ALL cells to the bone marrow of NOD/SCID mice by 40% compared with the DMSO controls (p<0.05). No inhibition of homing was observed with the inhibitors of PI-3K or MEK in ALL cells. These results support our previous in vitro findings with regards to the importance of the p38 MAPK pathway in SDF-1 induced motility of ALL cells and demonstrate that the same pathway plays an essential role in the homing of these cells to the bone marrow of NOD/SCID mice.

scholarly journals Merkel Cell Polyomavirus Small T Antigen Mediates Microtubule Destabilization To Promote Cell Motility and Migration

2014 ◽  
Vol 89 (1) ◽  
pp. 35-47 ◽  
Author(s):  
Laura M. Knight ◽  
Gabriele Stakaityte ◽  
Jennifer, J. Wood ◽  
Hussein Abdul-Sada ◽  
David A. Griffiths ◽  
...  
Keyword(s):  
Skin Cancer ◽  
Cell Motility ◽  
Cell Carcinoma ◽  
Merkel Cell Carcinoma ◽  
Tumor Antigen ◽  
Molecular Mechanisms ◽  
T Antigen ◽  
Merkel Cell Polyomavirus ◽  
Merkel Cell ◽  
Potential Link

ABSTRACTMerkel cell carcinoma (MCC) is an aggressive skin cancer of neuroendocrine origin with a high propensity for recurrence and metastasis. Merkel cell polyomavirus (MCPyV) causes the majority of MCC cases due to the expression of the MCPyV small and large tumor antigens (ST and LT, respectively). Although a number of molecular mechanisms have been attributed to MCPyV tumor antigen-mediated cellular transformation or replication, to date, no studies have investigated any potential link between MCPyV T antigen expression and the highly metastatic nature of MCC. Here we use a quantitative proteomic approach to show that MCPyV ST promotes differential expression of cellular proteins implicated in microtubule-associated cytoskeletal organization and dynamics. Intriguingly, we demonstrate that MCPyV ST expression promotes microtubule destabilization, leading to a motile and migratory phenotype. We further highlight the essential role of the microtubule-associated protein stathmin in MCPyV ST-mediated microtubule destabilization and cell motility and implicate the cellular phosphatase catalytic subunit protein phosphatase 4C (PP4C) in the regulation of this process. These findings suggest a possible molecular mechanism for the highly metastatic phenotype associated with MCC.IMPORTANCEMerkel cell polyomavirus (MCPyV) causes the majority of cases of Merkel cell carcinoma (MCC), an aggressive skin cancer with a high metastatic potential. However, the molecular mechanisms leading to virally induced cancer development have yet to be fully elucidated. In particular, no studies have investigated any potential link between the virus and the highly metastatic nature of MCC. We demonstrate that the MCPyV small tumor antigen (ST) promotes the destabilization of the host cell microtubule network, which leads to a more motile and migratory cell phenotype. We further show that MCPyV ST induces this process by regulating the phosphorylation status of the cellular microtubule-associated protein stathmin by its known association with the cellular phosphatase catalytic subunit PP4C. These findings highlight stathmin as a possible biomarker of MCC and as a target for novel antitumoral therapies.

Mechanisms and functions of p38 MAPK signalling

2010 ◽  
Vol 429 (3) ◽  
pp. 403-417 ◽  
Author(s):  
Ana Cuadrado ◽  
Angel R. Nebreda
Keyword(s):  
P38 Mapk ◽  
Molecular Mechanisms ◽  
Biological Effects ◽  
Mitogen Activated Protein Kinase ◽  
Wide Range ◽  
Mapk Signalling ◽  
Mitogen Activated Protein ◽  
External Signals ◽  
Protein Kinase Signalling ◽  
Genetic Mouse Models

The p38 MAPK (mitogen-activated protein kinase) signalling pathway allows cells to interpret a wide range of external signals and respond appropriately by generating a plethora of different biological effects. The diversity and specificity in cellular outcomes is achieved with an apparently simple linear architecture of the pathway, consisting of a core of three protein kinases acting sequentially. In the present review, we dissect the molecular mechanisms underlying p38 MAPK functions, with special emphasis on the activation and regulation of the core kinases, the interplay with other signalling pathways and the nature of p38 MAPK substrates as a source of functional diversity. Finally, we discuss how genetic mouse models are facilitating the identification of physiological functions for p38 MAPKs, which may impinge on their eventual use as therapeutic targets.

scholarly journals B7-H1(PD-L1) confers chemoresistance through ERK and p38 MAPK pathway in tumor cells

2018 ◽  
Author(s):  
Xiaosheng Wu ◽  
Yanli Li ◽  
Xin Liu ◽  
Siyu Cao ◽  
Susan M. Harrington ◽  
...  
Keyword(s):  
Tumor Cells ◽  
P38 Mapk ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
Mapk Pathway ◽  
Dependent Manner ◽  
Intracellular Signaling Pathway ◽  
Development Of Resistance ◽  
P38 Mapk Pathway

ABSTRACTDevelopment of resistance to chemotherapy and immunotherapy is a major obstacle in extending the survival of patients with cancer. Although several molecular mechanisms have been identified that can contribute to chemoresistance, the role of immune checkpoint molecules in tumor chemoresistance remains underestimated. It has been recently observed that overexpression of B7-H1(PD-L1) confers chemoresistance in human cancers, however the underlying mechanisms are unclear. Here we show that the development of chemoresistance depends on the increased activation of ERK pathway in tumor cells overexpressing B7-H1. Conversely, B7-H1 deficiency renders tumor cells susceptible to chemotherapy in a cell-context dependent manner through activation of the p38 MAPK pathway. B7-H1 in tumor cells associates with the catalytic subunit of a DNA-dependent serine / threonine protein kinase (DNA-PKcs). DNA-PKcs is required for the activation of ERK or p38 MAPK in tumors expressing B7-H1, but not in B7-H1 negative or B7-H1 deficient tumors. Ligation of B7-H1 by anti-B7-H1 monoclonal antibody (H1A) increased the sensitivity of human triple negative breast tumor cells to cisplatin therapy in vivo. Our results suggest that B7-H1(PD-L1) expression in cancer cells modifies their chemosensitivity towards certain drugs and targeting B7-H1 intracellular signaling pathway is a new way to overcome cancer chemoresistance.

scholarly journals p38δMAPK: Emerging Roles of a Neglected Isoform

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Carol O’Callaghan ◽  
Liam J. Fanning ◽  
Orla P. Barry
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Molecular Mechanisms ◽  
Mitogen Activated Protein Kinase ◽  
Biological Processes ◽  
Cellular Processes ◽  
Mapk Activity ◽  
Pathological Conditions ◽  
Mapk Signalling ◽  
Mitogen Activated Protein

p38δmitogen activated protein kinase (MAPK) is a unique stress responsive protein kinase. While the p38 MAPK family as a whole has been implicated in a wide variety of biological processes, a specific role for p38δMAPK in cellular signalling and its contribution to both physiological and pathological conditions are presently lacking. Recent emerging evidence, however, provides some insights into specific p38δMAPK signalling. Importantly, these studies have helped to highlight functional similarities as well as differences between p38δMAPK and the other members of the p38 MAPK family of kinases. In this review we discuss the current understanding of the molecular mechanisms underlying p38δMAPK activity. We outline a role for p38δMAPK in important cellular processes such as differentiation and apoptosis as well as pathological conditions such as neurodegenerative disorders, diabetes, and inflammatory disease. Interestingly, disparate roles for p38δMAPK in tumour development have also recently been reported. Thus, we consider evidence which characterises p38δMAPK as both a tumour promoter and a tumour suppressor. In summary, while our knowledge of p38δMAPK has progressed somewhat since its identification in 1997, our understanding of this particular isoform in many cellular processes still strikingly lags behind that of its counterparts.

Sign in / Sign up

Export Citation Format

Share Document