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Hoermann B, Dürr EM, Ludwig C, Ercan M, Köhn M. A strategy to disentangle direct and indirect effects on (de)phosphorylation by chemical modulators of the phosphatase PP1 in complex cellular contexts. Chem Sci 2024; 15:2792-2804. [PMID: 38404380 PMCID: PMC10882499 DOI: 10.1039/d3sc04746f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 01/12/2024] [Indexed: 02/27/2024] Open
Abstract
Chemical activators and inhibitors are useful probes to identify substrates and downstream effects of enzymes; however, due to the complex signaling environment within cells, it is challenging to distinguish between direct and indirect effects. This is particularly the case for phosphorylation, where a single (de)phosphorylation event can trigger rapid changes in many other phosphorylation sites. An additional complication arises when a single catalytic entity, which acts in the form of many different holoenzymes with different substrates, is activated or inhibited, as it is unclear which holoenzymes are affected, and in turn which of their substrates are (de)phosphorylated. Direct target engaging MS-based technologies to study targets of drugs do not address these challenges. Here, we tackle this by studying the modulation of protein phosphatase-1 (PP1) activity by PP1-disrupting peptides (PDPs), as well as their selectivity toward PP1, by using a combination of mass spectrometry-based experiments. By combining cellular treatment with the PDP with in vitro dephosphorylation by the enzyme, we identify high confidence substrate candidates and begin to separate direct and indirect effects. Together with experiments analyzing which holoenzymes are particularly susceptible to this treatment, we obtain insights into the effect of the modulator on the complex network of protein (de)phosphorylation. This strategy holds promise for enhancing our understanding of PP1 in particular and, due to the broad applicability of the workflow and the MS-based read-out, of chemical modulators with complex mode of action in general.
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Affiliation(s)
- Bernhard Hoermann
- Faculty of Biology, Institute of Biology III, University of Freiburg Freiburg Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg Freiburg Germany
| | - Eva-Maria Dürr
- Faculty of Biology, Institute of Biology III, University of Freiburg Freiburg Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg Freiburg Germany
| | - Christina Ludwig
- Chair of Proteomics and Bioanalytics, Technical University of Munich (TUM) Freising Germany
- Bavarian Center for Biomolecular Mass Spectrometry (BayBioMS), Technical University of Munich (TUM) Freising Germany
| | - Melda Ercan
- Faculty of Biology, Institute of Biology III, University of Freiburg Freiburg Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg Freiburg Germany
| | - Maja Köhn
- Faculty of Biology, Institute of Biology III, University of Freiburg Freiburg Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg Freiburg Germany
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2
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Riaud M, Maxwell J, Soria-Bretones I, Dankner M, Li M, Rose AAN. The role of CRAF in cancer progression: from molecular mechanisms to precision therapies. Nat Rev Cancer 2024; 24:105-122. [PMID: 38195917 DOI: 10.1038/s41568-023-00650-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/27/2023] [Indexed: 01/11/2024]
Abstract
The RAF family of kinases includes key activators of the pro-tumourigenic mitogen-activated protein kinase pathway. Hyperactivation of RAF proteins, particularly BRAF and CRAF, drives tumour progression and drug resistance in many types of cancer. Although BRAF is the most studied RAF protein, partially owing to its high mutation incidence in melanoma, the role of CRAF in tumourigenesis and drug resistance is becoming increasingly clinically relevant. Here, we summarize the main known regulatory mechanisms and gene alterations that contribute to CRAF activity, highlighting the different oncogenic roles of CRAF, and categorize RAF1 (CRAF) mutations according to the effect on kinase activity. Additionally, we emphasize the effect that CRAF alterations may have on drug resistance and how precision therapies could effectively target CRAF-dependent tumours. Here, we discuss preclinical and clinical findings that may lead to improved treatments for all types of oncogenic RAF1 alterations in cancer.
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Affiliation(s)
- Melody Riaud
- Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada
- Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada
| | - Jennifer Maxwell
- Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada
- Division of Experimental Medicine, Faculty of Medicine, McGill University, Montreal, Quebec, Canada
| | - Isabel Soria-Bretones
- Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada
- Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Matthew Dankner
- Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada
- Faculty of Medicine, McGill University, Montreal, Quebec, Canada
- Rosalind & Morris Goodman Cancer Institute, McGill University, Montreal, Quebec, Canada
| | - Meredith Li
- Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada
| | - April A N Rose
- Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada.
- Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada.
- Division of Experimental Medicine, Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
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3
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Hossain SM, Eccles MR. Phenotype Switching and the Melanoma Microenvironment; Impact on Immunotherapy and Drug Resistance. Int J Mol Sci 2023; 24:ijms24021601. [PMID: 36675114 PMCID: PMC9864717 DOI: 10.3390/ijms24021601] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/10/2023] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Melanoma, a highly heterogeneous tumor, is comprised of a functionally diverse spectrum of cell phenotypes and subpopulations, including stromal cells in the tumor microenvironment (TME). Melanoma has been shown to dynamically shift between different transcriptional states or phenotypes. This is referred to as phenotype switching in melanoma, and it involves switching between quiescent and proliferative cell cycle states, and dramatic shifts in invasiveness, as well as changes in signaling pathways in the melanoma cells, and immune cell composition in the TME. Melanoma cell plasticity is associated with altered gene expression in immune cells and cancer-associated fibroblasts, as well as changes in extracellular matrix, which drive the metastatic cascade and therapeutic resistance. Therefore, resistance to therapy in melanoma is not only dependent on genetic evolution, but it has also been suggested to be driven by gene expression changes and adaptive phenotypic cell plasticity. This review discusses recent findings in melanoma phenotype switching, immunotherapy resistance, and the balancing of the homeostatic TME between the different melanoma cell subpopulations. We also discuss future perspectives of the biology of neural crest-like state(s) in melanoma.
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Affiliation(s)
- Sultana Mehbuba Hossain
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin 9016, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Level 2, 3A Symonds Street, Auckland 1010, New Zealand
| | - Michael R. Eccles
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin 9016, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, Level 2, 3A Symonds Street, Auckland 1010, New Zealand
- Correspondence:
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Qian Y, Zhou L, Luk STY, Xu J, Li W, Gou H, Chen H, Kang W, Yu J, Wong CC. The sodium channel subunit SCNN1B suppresses colorectal cancer via suppression of active c-Raf and MAPK signaling cascade. Oncogene 2023; 42:601-612. [PMID: 36564468 PMCID: PMC9937924 DOI: 10.1038/s41388-022-02576-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 12/02/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022]
Abstract
The incidence of colorectal cancer (CRC) is rising worldwide. Here, we identified SCNN1B as an outlier down-regulated in CRC and it functions as a tumor suppressor. SCNN1B mRNA and protein expression were down-regulated in primary CRC and CRC cells. In a tissue microarray cohort (N = 153), SCNN1B protein was an independent prognostic factor for favorable outcomes in CRC. Ectopic expression of SCNN1B in CRC cell lines suppressed cell proliferation, induced apoptosis, and cell cycle arrest, and suppressed cell migration in vitro. Xenograft models validated tumor suppressive function of SCNN1B in vivo. Mechanistically, Gene Set Enrichment Analysis (GSEA) showed that SCNN1B correlates with KRAS signaling. Consistently, MAPK qPCR and kinase arrays revealed that SCNN1B suppressed MAPK signaling. In particular, SCNN1B overexpression suppressed p-MEK/p-ERK expression and SRE-mediated transcription activities, confirming blockade of Ras-Raf-MEK-ERK cascade. Mechanistically, SCNN1B did not affect KRAS activation, instead impairing activation of c-Raf by inducing its inhibitory phosphorylation and targeting active c-Raf for degradation. The ectopic expression of c-Raf fully rescued cell proliferation and colony formation in SCNN1B-overexpressing CRC cells, confirming c-Raf as the principal molecular target of SCNN1B. In summary, we identified SCNN1B as a tumor suppressor by functioning as a c-Raf antagonist, which in turn suppressed oncogenic MEK-ERK signaling.
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Affiliation(s)
- Yun Qian
- grid.263488.30000 0001 0472 9649Department of Gastroenterology and Hepatology, Shenzhen University General Hospital, Shenzhen, China ,grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease, Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Lianxin Zhou
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease, Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Simson Tsz Yat Luk
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease, Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jiaying Xu
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease, Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Weilin Li
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease, Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Hongyan Gou
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease, Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Huarong Chen
- grid.10784.3a0000 0004 1937 0482Institute of Digestive Disease, Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Wei Kang
- grid.10784.3a0000 0004 1937 0482Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jun Yu
- Institute of Digestive Disease, Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China.
| | - Chi Chun Wong
- Institute of Digestive Disease, Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China.
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5
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Xu C, Cheng Y, Han M, Tao Y, Liu JG. The Agonist of Adenosine A1 Receptor Induced Desensitization of delta Opioid receptor-mediated Raf-1/MEK/ERK Signaling by Feedback Phosphorylation of Raf-1-Ser289/296/301. Neurochem Res 2022; 48:1531-1542. [PMID: 36525124 DOI: 10.1007/s11064-022-03843-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/22/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022]
Abstract
Our previous study found that activation of adenosine A1 receptor (A1R) induced phosphorylation of delta opioid receptor (DOR) and desensitization of its downstream signaling molecules, cAMP and Akt. To further investigate the effect of A1R agonist on DOR signaling and the underlying mechanism, we examined the effect of A1R activation upon binding of its agonist N6-cyclohexyl-adenosine (CHA) on DOR-mediated Raf-1/MEK/ERK activation, and found that prolonged CHA exposure resulted in downregulation of DOR-mediated Raf-1/MEK/ERK signaling pathway. CHA-treatment time dependently attenuated Raf-1-Ser338 phosphorylation induced by [D-Pen2,5] enkephalin (DPDPE), a specific agonist of DOR, and further caused downregulation of the Raf-1/MEK/ERK signaling pathway activated by DOR agonist. Moreover, CHA exposure time-dependently induced the phosphorylation of Raf-1-Ser289/296/301, the inhibitory phosphorylation sites that were regulated by negative feedback, thereby inhibiting activation of the MEK/ERK pathway, and this effect could be blocked by MEK inhibitor U0126. Finally, we proved that the heterologous desensitization of the Raf-1/MEK/ERK cascade was essential in the regulation of anti-nociceptive effect of DOR agonists by confirming that such effect was inhibited by pretreatment of CHA. Therefore, we conclude that the activation of A1R inhibits DOR-mediated MAPK signaling pathway via heterologous desensitization of the Raf-1/MEK/ERK cascade, which is a result of ERK-mediated Raf-1-Ser289/296/301 phosphorylation mediated by activation of A1R.
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Zhao J, Luo Z. Discovery of Raf Family Is a Milestone in Deciphering the Ras-Mediated Intracellular Signaling Pathway. Int J Mol Sci 2022; 23:ijms23095158. [PMID: 35563547 PMCID: PMC9101324 DOI: 10.3390/ijms23095158] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/02/2022] [Accepted: 05/03/2022] [Indexed: 01/27/2023] Open
Abstract
The Ras-Raf-MEK-ERK signaling pathway, the first well-established MAPK pathway, plays essential roles in cell proliferation, survival, differentiation and development. It is activated in over 40% of human cancers owing to mutations of Ras, membrane receptor tyrosine kinases and other oncogenes. The Raf family consists of three isoforms, A-Raf, B-Raf and C-Raf. Since the first discovery of a truncated mutant of C-Raf as a transforming oncogene carried by a murine retrovirus, forty years of extensive studies have provided a wealth of information on the mechanisms underlying the activation, regulation and biological functions of the Raf family. However, the mechanisms by which activation of A-Raf and C-Raf is accomplished are still not completely understood. In contrast, B-Raf can be easily activated by binding of Ras-GTP, followed by cis-autophosphorylation of the activation loop, which accounts for the fact that this isoform is frequently mutated in many cancers, especially melanoma. The identification of oncogenic B-Raf mutations has led to accelerated drug development that targets Raf signaling in cancer. However, the effort has not proved as effective as anticipated, inasmuch as the mechanism of Raf activation involves multiple steps, factors and phosphorylation of different sites, as well as complex interactions between Raf isoforms. In this review, we will focus on the physiological complexity of the regulation of Raf kinases and their connection to the ERK phosphorylation cascade and then discuss the role of Raf in tumorigenesis and the clinical application of Raf inhibitors in the treatment of cancer.
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Affiliation(s)
- Jingtong Zhao
- Queen Mary School, Nanchang University, Nanchang 330031, China;
| | - Zhijun Luo
- Queen Mary School, Nanchang University, Nanchang 330031, China;
- Provincial Key Laboratory of Tumor Pathogens and Molecular Pathology, Nanchang University, Nanchang 330031, China
- NCU-QMUL Joint Research Institute of Precision Medical Science, Nanchang 330031, China
- Correspondence:
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7
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Keshishian H, McDonald ER, Mundt F, Melanson R, Krug K, Porter DA, Wallace L, Forestier D, Rabasha B, Marlow SE, Jane‐Valbuena J, Todres E, Specht H, Robinson ML, Jean Beltran PM, Babur O, Olive ME, Golji J, Kuhn E, Burgess M, MacMullan MA, Rejtar T, Wang K, Mani DR, Satpathy S, Gillette MA, Sellers WR, Carr SA. A highly multiplexed quantitative phosphosite assay for biology and preclinical studies. Mol Syst Biol 2021; 17:e10156. [PMID: 34569154 PMCID: PMC8474009 DOI: 10.15252/msb.202010156] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 12/14/2022] Open
Abstract
Reliable methods to quantify dynamic signaling changes across diverse pathways are needed to better understand the effects of disease and drug treatment in cells and tissues but are presently lacking. Here, we present SigPath, a targeted mass spectrometry (MS) assay that measures 284 phosphosites in 200 phosphoproteins of biological interest. SigPath probes a broad swath of signaling biology with high throughput and quantitative precision. We applied the assay to investigate changes in phospho-signaling in drug-treated cancer cell lines, breast cancer preclinical models, and human medulloblastoma tumors. In addition to validating previous findings, SigPath detected and quantified a large number of differentially regulated phosphosites newly associated with disease models and human tumors at baseline or with drug perturbation. Our results highlight the potential of SigPath to monitor phosphoproteomic signaling events and to nominate mechanistic hypotheses regarding oncogenesis, response, and resistance to therapy.
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Affiliation(s)
- Hasmik Keshishian
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | | | - Filip Mundt
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
- Present address:
Novo Nordisk Foundation Center for Protein ResearchFaculty of Health SciencesUniversity of CopenhagenCopenhagenDenmark
- Present address:
Department of Oncology and PathologyScience for Life LaboratoryKarolinska InstitutetStockholmSweden
| | - Randy Melanson
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Karsten Krug
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Dale A Porter
- Novartis Institute of Biomedical ResearchCambridgeMAUSA
- Present address:
Cedilla TherapeuticsCambridgeMAUSA
| | - Luke Wallace
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Dominique Forestier
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Bokang Rabasha
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Sara E Marlow
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Judit Jane‐Valbuena
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Ellen Todres
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Harrison Specht
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | | | | | - Ozgun Babur
- Computer Science DepartmentUniversity of Massachusetts BostonBostonMAUSA
| | - Meagan E Olive
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Javad Golji
- Novartis Institute of Biomedical ResearchCambridgeMAUSA
| | - Eric Kuhn
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Michael Burgess
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Melanie A MacMullan
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Tomas Rejtar
- Novartis Institute of Biomedical ResearchCambridgeMAUSA
| | - Karen Wang
- Novartis Institute of Biomedical ResearchCambridgeMAUSA
| | - DR Mani
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Shankha Satpathy
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
| | - Michael A Gillette
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
- Division of Pulmonary and Critical Care MedicineMassachusetts General HospitalBostonMAUSA
| | - William R Sellers
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
- Department of Medical OncologyDana‐Farber Cancer Institute and Harvard Medical SchoolBostonMAUSA
| | - Steven A Carr
- Broad Institute of Massachusetts Institute of Technology and HarvardCambridgeMAUSA
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8
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Mitochondrial Targeting of the Enteropathogenic Escherichia coli Map Triggers Calcium Mobilization, ADAM10-MAP Kinase Signaling, and Host Cell Apoptosis. mBio 2020; 11:mBio.01397-20. [PMID: 32934081 PMCID: PMC7492733 DOI: 10.1128/mbio.01397-20] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Enteropathogenic E. coli (EPEC) is an important human diarrhea-causing bacterium. The pathogenic effects of EPEC largely depend upon its ability to inject a series of proteins, termed effectors, into the host cells. One such effector is the mitochondrion-associated protein (Map). Map has been shown to induce actin-rich projections (i.e., filopodia) on the infected cell surface and activate a Rho GTPase enzyme termed Cdc42. Nonetheless, although most injected Map localizes to host mitochondria, its functions in the mitochondria remain unknown. Here, we show that Map targeting of mitochondria stimulates the disruption of mitochondrial membrane potential to induce Ca2+ efflux into the host cytoplasm. The efflux stimulates the activity of a protein termed ADAM10, which induces activation of a mitogen-activated protein kinase cascade leading to host cell apoptosis. As apoptosis plays a central role in host-pathogen interactions, our findings provide novel insights into the functions of mitochondrial Map in promoting the EPEC disease. The ability of diarrheagenic bacterial pathogens, such as enteropathogenic Escherichia coli (EPEC), to modulate the activity of mitogen-activated protein kinases (MAPKs) and cell survival has been suggested to benefit bacterial colonization and infection. However, our understanding of the mechanisms by which EPEC modulate these functions is incomplete. In this study, we show that the EPEC type III secreted effector Map stimulates the sheddase activity of the disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) and the ERK and p38 MAPK signaling cascades. Remarkably, all these activities were dependent upon the ability of Map to target host mitochondria, mainly via its mitochondrial toxicity region (MTR). Map targeting of mitochondria disrupted the mitochondrial membrane potential, causing extrusion of mitochondrial Ca2+ into the host cell cytoplasm. We also found that Map targeting of mitochondria is essential for triggering host cell apoptosis. Based on these findings, we propose a model whereby Map imported into mitochondria causes mitochondrial dysfunction and Ca2+ efflux into the host cytoplasm. Since Ca2+ has been reported to promote ADAM10 activation, the acute elevation of Ca2+ in the cytoplasm may stimulate the ADAM10 sheddase activity, resulting in the release of epidermal growth factors that stimulate the ERK signaling cascade. As p38 activity is also Ca2+ sensitive, elevation in cytoplasmic Ca2+ may independently also activate p38. We hypothesize that Map-dependent MAPK activation, combined with Map-mediated mitochondrial dysfunction, evokes mitochondrial host cell apoptosis, potentially contributing to EPEC colonization and infection of the gut.
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Miningou N, Blackwell KT. The road to ERK activation: Do neurons take alternate routes? Cell Signal 2020; 68:109541. [PMID: 31945453 PMCID: PMC7127974 DOI: 10.1016/j.cellsig.2020.109541] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 01/11/2020] [Accepted: 01/12/2020] [Indexed: 01/29/2023]
Abstract
The ERK cascade is a central signaling pathway that regulates a wide variety of cellular processes including proliferation, differentiation, learning and memory, development, and synaptic plasticity. A wide range of inputs travel from the membrane through different signaling pathway routes to reach activation of one set of output kinases, ERK1&2. The classical ERK activation pathway beings with growth factor activation of receptor tyrosine kinases. Numerous G-protein coupled receptors and ionotropic receptors also lead to ERK through increases in the second messengers calcium and cAMP. Though both types of pathways are present in diverse cell types, a key difference is that most stimuli to neurons, e.g. synaptic inputs, are transient, on the order of milliseconds to seconds, whereas many stimuli acting on non-neural tissue, e.g. growth factors, are longer duration. The ability to consolidate these inputs to regulate the activation of ERK in response to diverse signals raises the question of which factors influence the difference in ERK activation pathways. This review presents both experimental studies and computational models aimed at understanding the control of ERK activation and whether there are fundamental differences between neurons and other cells. Our main conclusion is that differences between cell types are quite subtle, often related to differences in expression pattern and quantity of some molecules such as Raf isoforms. In addition, the spatial location of ERK is critical, with regulation by scaffolding proteins producing differences due to colocalization of upstream molecules that may differ between neurons and other cells.
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Affiliation(s)
- Nadiatou Miningou
- Department of Chemistry and Biochemistry, George Mason University, Fairfax, VA 22030, United States of America
| | - Kim T Blackwell
- Interdisciplinary Program in Neuroscience and Bioengineering Department, George Mason University, Fairfax, VA 22030, United States of America.
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RAF kinases are stabilized and required for dendritic cell differentiation and function. Cell Death Differ 2019; 27:1300-1315. [PMID: 31541179 PMCID: PMC7206131 DOI: 10.1038/s41418-019-0416-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 07/23/2019] [Accepted: 08/30/2019] [Indexed: 12/05/2022] Open
Abstract
RAF kinases (ARAF, BRAF, and CRAF) are highly conserved enzymes that trigger the RAF-MEK1/2-ERK1/2 (MAPK) pathway upon activation of RAS. Despite enormous clinical interest, relatively little is known on the role of RAFs in mediating immune responses. Here, we investigated the role of RAF kinases and MEK1/2 in dendritic cells (DCs), the central regulators of T cell-mediated antitumor immune responses and the adaptive immune system. We demonstrate that RAF kinases are active and stabilized at their protein levels during DC differentiation. Inhibition of RAF kinases but not MEK1/2 impaired the activation of DCs in both mice and human. As expected, DCs treated with RAF inhibitors show defects in activating T cells. Further, RAF and MEK1/2 kinases are directly required for the activation and proliferation of CD4+ T cells. Our observations suggest that RAF and MEK1/2 have independent roles in regulating DC function that has important implications for administering RAF–MAPK inhibitors in the clinics.
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Smolen P, Baxter DA, Byrne JH. How can memories last for days, years, or a lifetime? Proposed mechanisms for maintaining synaptic potentiation and memory. ACTA ACUST UNITED AC 2019; 26:133-150. [PMID: 30992383 PMCID: PMC6478248 DOI: 10.1101/lm.049395.119] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 03/12/2019] [Indexed: 01/24/2023]
Abstract
With memory encoding reliant on persistent changes in the properties of synapses, a key question is how can memories be maintained from days to months or a lifetime given molecular turnover? It is likely that positive feedback loops are necessary to persistently maintain the strength of synapses that participate in encoding. Such feedback may occur within signal-transduction cascades and/or the regulation of translation, and it may occur within specific subcellular compartments or within neuronal networks. Not surprisingly, numerous positive feedback loops have been proposed. Some posited loops operate at the level of biochemical signal-transduction cascades, such as persistent activation of Ca2+/calmodulin kinase II (CaMKII) or protein kinase Mζ. Another level consists of feedback loops involving transcriptional, epigenetic and translational pathways, and autocrine actions of growth factors such as BDNF. Finally, at the neuronal network level, recurrent reactivation of cell assemblies encoding memories is likely to be essential for late maintenance of memory. These levels are not isolated, but linked by shared components of feedback loops. Here, we review characteristics of some commonly discussed feedback loops proposed to underlie the maintenance of memory and long-term synaptic plasticity, assess evidence for and against their necessity, and suggest experiments that could further delineate the dynamics of these feedback loops. We also discuss crosstalk between proposed loops, and ways in which such interaction can facilitate the rapidity and robustness of memory formation and storage.
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Affiliation(s)
- Paul Smolen
- Department of Neurobiology and Anatomy, W. M. Keck Center for the Neurobiology of Learning and Memory, McGovern Medical School of the University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Douglas A Baxter
- Department of Neurobiology and Anatomy, W. M. Keck Center for the Neurobiology of Learning and Memory, McGovern Medical School of the University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - John H Byrne
- Department of Neurobiology and Anatomy, W. M. Keck Center for the Neurobiology of Learning and Memory, McGovern Medical School of the University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
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12
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Zou J, Lei T, Guo P, Yu J, Xu Q, Luo Y, Ke R, Huang D. Mechanisms shaping the role of ERK1/2 in cellular senescence (Review). Mol Med Rep 2018; 19:759-770. [PMID: 30535440 PMCID: PMC6323238 DOI: 10.3892/mmr.2018.9712] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 10/10/2018] [Indexed: 01/19/2023] Open
Abstract
Senescence is a result of cellular stress and is a potential mechanism for regulating cancer. As a member of the mitogen-activated protein kinase family, ERK1/2 (extracellular signal-regulated protein kinase) has an important role in delivering extracellular signals to the nucleus, and these signals regulate the cell cycle, cell proliferation and cell development. Previous studies demonstrated that ERK1/2 is closely associated with cell aging; however other previous studies suggested that ERK1/2 exerts an opposite effect on aging models and target proteins, even within the same cell model. Recent studies demonstrated that the effect of ERK1/2 on aging is likely associated with its target proteins and regulators, negative feedback loops, phosphorylated ERK1/2 factors and ERK1/2 translocation from the cytoplasm to the nucleus. The present review aims to examine the mechanism of ERK1/2 and discuss its role in cellular outcomes and novel drug development.
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Affiliation(s)
- Junrong Zou
- Research Institute of Digestive Diseases, Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Tingting Lei
- Research Institute of Digestive Diseases, Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Pei Guo
- Department of Pathology, Shenzhen Hospital of Southern Medical University, Shenzhen, Guangdong 518110, P.R. China
| | - Jason Yu
- Department of Pharmacology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Qichao Xu
- Department of Pharmacology, The People's Hospital of Xinyu City, Xinyu, Jiangxi 338025, P.R. China
| | - Yunfei Luo
- Jiangxi Provincial Key Laboratory of Tumor Pathogenesis and Molecular Pathology, Department of Pathophysiology, School of Basic Medical Sciences, Medical College of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Rong Ke
- Department of Surgery, University of Illinois at Chicago College of Medicine, Chicago, IL 60612, USA
| | - Deqiang Huang
- Research Institute of Digestive Diseases, Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
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13
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Merchant M, Moffat J, Schaefer G, Chan J, Wang X, Orr C, Cheng J, Hunsaker T, Shao L, Wang SJ, Wagle MC, Lin E, Haverty PM, Shahidi-Latham S, Ngu H, Solon M, Eastham-Anderson J, Koeppen H, Huang SMA, Schwarz J, Belvin M, Kirouac D, Junttila MR. Combined MEK and ERK inhibition overcomes therapy-mediated pathway reactivation in RAS mutant tumors. PLoS One 2017; 12:e0185862. [PMID: 28982154 PMCID: PMC5628883 DOI: 10.1371/journal.pone.0185862] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 09/20/2017] [Indexed: 12/19/2022] Open
Abstract
Mitogen-activated protein kinase (MAPK) pathway dysregulation is implicated in >30% of all cancers, rationalizing the development of RAF, MEK and ERK inhibitors. While BRAF and MEK inhibitors improve BRAF mutant melanoma patient outcomes, these inhibitors had limited success in other MAPK dysregulated tumors, with insufficient pathway suppression and likely pathway reactivation. In this study we show that inhibition of either MEK or ERK alone only transiently inhibits the MAPK pathway due to feedback reactivation. Simultaneous targeting of both MEK and ERK nodes results in deeper and more durable suppression of MAPK signaling that is not achievable with any dose of single agent, in tumors where feedback reactivation occurs. Strikingly, combined MEK and ERK inhibition is synergistic in RAS mutant models but only additive in BRAF mutant models where the RAF complex is dissociated from RAS and thus feedback productivity is disabled. We discovered that pathway reactivation in RAS mutant models occurs at the level of CRAF with combination treatment resulting in a markedly more active pool of CRAF. However, distinct from single node targeting, combining MEK and ERK inhibitor treatment effectively blocks the downstream signaling as assessed by transcriptional signatures and phospho-p90RSK. Importantly, these data reveal that MAPK pathway inhibitors whose activity is attenuated due to feedback reactivation can be rescued with sufficient inhibition by using a combination of MEK and ERK inhibitors. The MEK and ERK combination significantly suppresses MAPK pathway output and tumor growth in vivo to a greater extent than the maximum tolerated doses of single agents, and results in improved anti-tumor activity in multiple xenografts as well as in two Kras mutant genetically engineered mouse (GEM) models. Collectively, these data demonstrate that combined MEK and ERK inhibition is functionally unique, yielding greater than additive anti-tumor effects and elucidates a highly effective combination strategy in MAPK-dependent cancer, such as KRAS mutant tumors.
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Affiliation(s)
- Mark Merchant
- Department of Translational Oncology, Genentech, Inc., South San Francisco, California, United States of America
| | - John Moffat
- Department of Biochemical and Cellular Pharmacology, Genentech, Inc., South San Francisco, California, United States of America
| | - Gabriele Schaefer
- Department of Translational Oncology, Genentech, Inc., South San Francisco, California, United States of America
| | - Jocelyn Chan
- Department of Translational Oncology, Genentech, Inc., South San Francisco, California, United States of America
| | - Xi Wang
- Department of Translational Oncology, Genentech, Inc., South San Francisco, California, United States of America
| | - Christine Orr
- Department of Translational Oncology, Genentech, Inc., South San Francisco, California, United States of America
| | - Jason Cheng
- Department of Translational Oncology, Genentech, Inc., South San Francisco, California, United States of America
| | - Thomas Hunsaker
- Department of Translational Oncology, Genentech, Inc., South San Francisco, California, United States of America
| | - Lily Shao
- Department of Translational Oncology, Genentech, Inc., South San Francisco, California, United States of America
| | - Stephanie J. Wang
- Department of Biological Engineering, The Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Marie-Claire Wagle
- Department of Oncology Biomarker Development, Genentech, Inc., South San Francisco, California, United States of America
| | - Eva Lin
- Department of Discovery Oncology, Genentech, Inc., South San Francisco, California, United States of America
| | - Peter M. Haverty
- Department of Bioinformatics, Genentech, Inc., South San Francisco, California, United States of America
| | - Sheerin Shahidi-Latham
- Department of Drug Metabolism and Pharmacokinetics, Genentech, Inc., South San Francisco, California, United States of America
| | - Hai Ngu
- Department of Pathology, Genentech, Inc., South San Francisco, California, United States of America
| | - Margaret Solon
- Department of Discovery Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Jeffrey Eastham-Anderson
- Department of Pathology, Genentech, Inc., South San Francisco, California, United States of America
| | - Hartmut Koeppen
- Department of Pathology, Genentech, Inc., South San Francisco, California, United States of America
| | - Shih-Min A. Huang
- Department of Oncology Biomarker Development, Genentech, Inc., South San Francisco, California, United States of America
| | - Jacob Schwarz
- Department of Discovery Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Marcia Belvin
- Department of Cancer Immunology, Genentech, Inc., South San Francisco, California, United States of America
| | - Daniel Kirouac
- Department of Pre-clinical & Translational Pharmacokinetics Genentech, Inc., South San Francisco, California, United States of America
| | - Melissa R. Junttila
- Department of Translational Oncology, Genentech, Inc., South San Francisco, California, United States of America
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14
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Goglia AG, Wilson MZ, DiGiorno DB, Toettcher JE. Optogenetic Control of Ras/Erk Signaling Using the Phy-PIF System. Methods Mol Biol 2017; 1636:3-20. [PMID: 28730469 DOI: 10.1007/978-1-4939-7154-1_1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The Ras/Erk signaling pathway plays a central role in diverse cellular processes ranging from development to immune cell activation to neural plasticity to cancer. In recent years, this pathway has been widely studied using live-cell fluorescent biosensors, revealing complex Erk dynamics that arise in many cellular contexts. Yet despite these high-resolution tools for measurement, the field has lacked analogous tools for control over Ras/Erk signaling in live cells. Here, we provide detailed methods for one such tool based on the optical control of Ras activity, which we call "Opto-SOS." Expression of the Opto-SOS constructs can be coupled with a live-cell reporter of Erk activity to reveal highly quantitative input-to-output maps of the pathway. Detailed herein are protocols for expressing the Opto-SOS system in cultured cells, purifying the small molecule cofactor necessary for optical stimulation, imaging Erk responses using live-cell microscopy, and processing the imaging data to quantify Ras/Erk signaling dynamics.
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Affiliation(s)
- Alexander G Goglia
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory Room 140, Washington Road, Princeton, NJ, 08544, USA
- Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, USA
| | - Maxwell Z Wilson
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory Room 140, Washington Road, Princeton, NJ, 08544, USA
| | - Daniel B DiGiorno
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory Room 140, Washington Road, Princeton, NJ, 08544, USA
| | - Jared E Toettcher
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory Room 140, Washington Road, Princeton, NJ, 08544, USA.
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15
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Lake D, Corrêa SAL, Müller J. Negative feedback regulation of the ERK1/2 MAPK pathway. Cell Mol Life Sci 2016; 73:4397-4413. [PMID: 27342992 PMCID: PMC5075022 DOI: 10.1007/s00018-016-2297-8] [Citation(s) in RCA: 351] [Impact Index Per Article: 43.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 06/16/2016] [Accepted: 06/17/2016] [Indexed: 01/04/2023]
Abstract
The extracellular signal-regulated kinase 1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) signalling pathway regulates many cellular functions, including proliferation, differentiation, and transformation. To reliably convert external stimuli into specific cellular responses and to adapt to environmental circumstances, the pathway must be integrated into the overall signalling activity of the cell. Multiple mechanisms have evolved to perform this role. In this review, we will focus on negative feedback mechanisms and examine how they shape ERK1/2 MAPK signalling. We will first discuss the extensive number of negative feedback loops targeting the different components of the ERK1/2 MAPK cascade, specifically the direct posttranslational modification of pathway components by downstream protein kinases and the induction of de novo gene synthesis of specific pathway inhibitors. We will then evaluate how negative feedback modulates the spatiotemporal signalling dynamics of the ERK1/2 pathway regarding signalling amplitude and duration as well as subcellular localisation. Aberrant ERK1/2 activation results in deregulated proliferation and malignant transformation in model systems and is commonly observed in human tumours. Inhibition of the ERK1/2 pathway thus represents an attractive target for the treatment of malignant tumours with increased ERK1/2 activity. We will, therefore, discuss the effect of ERK1/2 MAPK feedback regulation on cancer treatment and how it contributes to reduced clinical efficacy of therapeutic agents and the development of drug resistance.
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Affiliation(s)
- David Lake
- Warwick Medical School, University of Warwick, Coventry, UK
| | - Sonia A L Corrêa
- School of Life Sciences, University of Warwick, Coventry, UK
- Faculty of Life Sciences, University of Bradford, Bradford, UK
| | - Jürgen Müller
- Warwick Medical School, University of Warwick, Coventry, UK.
- Aston Medical Research Institute, Aston Medical School, Aston University, Birmingham, B4 7ET, UK.
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16
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Mass spectrometric phosphoproteome analysis of small-sized samples of human neutrophils. Clin Chim Acta 2015; 451:199-207. [DOI: 10.1016/j.cca.2015.09.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 09/21/2015] [Accepted: 09/29/2015] [Indexed: 12/28/2022]
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17
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LIU RUI, WANG WENJIE, DAI BINGLING, LIU YANPING, ZHANG YANMIN. Taspine derivative TAS9 regulates cell growth and metastasis of human hepatocellular carcinoma. Mol Med Rep 2015; 12:7735-41. [DOI: 10.3892/mmr.2015.4398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 08/04/2015] [Indexed: 11/05/2022] Open
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18
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Sparta B, Pargett M, Minguet M, Distor K, Bell G, Albeck JG. Receptor Level Mechanisms Are Required for Epidermal Growth Factor (EGF)-stimulated Extracellular Signal-regulated Kinase (ERK) Activity Pulses. J Biol Chem 2015; 290:24784-92. [PMID: 26304118 DOI: 10.1074/jbc.m115.662247] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Indexed: 11/06/2022] Open
Abstract
In both physiological and cell culture systems, EGF-stimulated ERK activity occurs in discrete pulses within individual cells. Many feedback loops are present in the EGF receptor (EGFR)-ERK network, but the mechanisms driving pulsatile ERK kinetics are unknown. Here, we find that in cells that respond to EGF with frequency-modulated pulsatile ERK activity, stimulation through a heterologous TrkA receptor system results in non-pulsatile, amplitude-modulated activation of ERK. We further dissect the kinetics of pulse activity using a combination of FRET- and translocation-based reporters and find that EGFR activity is required to maintain ERK activity throughout the 10-20-minute lifetime of pulses. Together, these data indicate that feedbacks operating within the core Ras-Raf-MEK-ERK cascade are insufficient to drive discrete pulses of ERK activity and instead implicate mechanisms acting at the level of EGFR.
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Affiliation(s)
- Breanne Sparta
- From the Departments of Molecular and Cellular Biology and
| | | | - Marta Minguet
- From the Departments of Molecular and Cellular Biology and
| | - Kevin Distor
- From the Departments of Molecular and Cellular Biology and
| | - George Bell
- Microbiology and Molecular Genetics, University of California, Davis, California 95616
| | - John G Albeck
- From the Departments of Molecular and Cellular Biology and
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19
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Jensen HA, Bunaciu RP, Varner JD, Yen A. GW5074 and PP2 kinase inhibitors implicate nontraditional c-Raf and Lyn function as drivers of retinoic acid-induced maturation. Cell Signal 2015; 27:1666-75. [PMID: 25817574 PMCID: PMC4529126 DOI: 10.1016/j.cellsig.2015.03.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/05/2015] [Accepted: 03/16/2015] [Indexed: 02/07/2023]
Abstract
The multivariate nature of cancer necessitates multi-targeted therapy, and kinase inhibitors account for a vast majority of approved cancer therapeutics. While acute promyelocytic leukemia (APL) patients are highly responsive to retinoic acid (RA) therapy, kinase inhibitors have been gaining momentum as co-treatments with RA for non-APL acute myeloid leukemia (AML) differentiation therapies, especially as a means to treat relapsed or refractory AML patients. In this study GW5074 (a c-Raf inhibitor) and PP2 (a Src-family kinase inhibitor) enhanced RA-induced maturation of t(15;17)-negative myeloblastic leukemia cells and rescued response in RA-resistant cells. PD98059 (a MEK inhibitor) and Akti-1/2 (an Akt inhibitor) were less effective, but did tend to promote maturation-uncoupled G1/G0 arrest, while wortmannin (a PI3K inhibitor) did not enhance differentiation surface marker expression or growth arrest. PD98059 and Akti-1/2 did not enhance differentiation markers and have potential, antagonistic off-targets effects on the aryl hydrocarbon receptor (AhR), but neither could the AhR agonist 6-formylindolo(3,2-b)carbazole (FICZ) rescue differentiation events in the RA-resistant cells. GW5074 rescued early CD38 expression in RA-resistant cells exhibiting an early block in differentiation before CD38 expression, while for RA-resistant cells with differentiation blocked later, PP2 rescued the later differentiation marker CD11b; but surprisingly, the combination of the two was not synergistic. Kinases c-Raf, Src-family kinases Lyn and Fgr, and PI3K display highly correlated signaling changes during RA treatment, while activation of traditional downstream targets (Akt, MEK/ERK), and even the surface marker CD38, were poorly correlated with c-Raf or Lyn during differentiation. This suggests that an interrelated kinase module involving c-Raf, PI3K, Lyn and perhaps Fgr functions in a nontraditional way during RA-induced maturation or during rescue of RA induction therapy using inhibitor co-treatment in RA-resistant leukemia cells.
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Affiliation(s)
- Holly A Jensen
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States
| | - Rodica P Bunaciu
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, United States
| | - Jeffrey D Varner
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States
| | - Andrew Yen
- Department of Biomedical Sciences, Cornell University, Ithaca, NY, United States
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20
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Jung KH, Kim SR, Giong HK, Nguyen MX, Koh HJ, An G. Genome-wide identification and functional analysis of genes expressed ubiquitously in rice. MOLECULAR PLANT 2015; 8:276-89. [PMID: 25624149 DOI: 10.1016/j.molp.2014.10.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 10/07/2014] [Accepted: 10/07/2014] [Indexed: 05/10/2023]
Abstract
Genes that are expressed ubiquitously throughout all developmental stages are thought to be necessary for basic biological or cellular functions. Therefore, determining their biological roles is a great challenge. We identified 4034 of these genes in rice after studying the results of Agilent 44K and Affymetrix meta-anatomical expression profiles. Among 105 genes that were characterized by loss-of-function analysis, 79 were classified as members of gene families, the majority of which were predominantly expressed. Using T-DNA insertional mutants, we examined 43 genes and found that loss of expression of six genes caused developing seed- or seedling-defective phenotypes. Of these, three are singletons without similar family members and defective phenotypes are expected from mutations. Phylogenomic analyses integrating genome-wide transcriptome data revealed the functional dominance of three ubiquitously expressed family genes. Among them, we investigated the function of Os03g19890, which is involved in ATP generation within the mitochondria during endosperm development. We also created and evaluated functional networks associated with this gene to understand the molecular mechanism. Our study provides a useful strategy for pheonome analysis of ubiquitously expressed genes in rice.
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Affiliation(s)
- Ki-Hong Jung
- Department of Plant Molecular Systems Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Korea; Graduate School of Biotechnology, Kyung Hee University, Yongin 446-701, Korea.
| | - Sung-Ruyl Kim
- Department of Plant Molecular Systems Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Korea
| | - Hoi-Khoanh Giong
- Department of Plant Molecular Systems Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Korea
| | - Minh Xuan Nguyen
- Department of Plant Molecular Systems Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Korea
| | - Hyun-Jung Koh
- Department of Plant Molecular Systems Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Korea
| | - Gynheung An
- Department of Plant Molecular Systems Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Korea; Graduate School of Biotechnology, Kyung Hee University, Yongin 446-701, Korea.
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21
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An S, Yang Y, Ward R, Liu Y, Guo XX, Xu TR. Raf-interactome in tuning the complexity and diversity of Raf function. FEBS J 2014; 282:32-53. [PMID: 25333451 DOI: 10.1111/febs.13113] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/06/2014] [Accepted: 10/14/2014] [Indexed: 12/23/2022]
Abstract
Raf kinases have been intensely studied subsequent to their discovery 30 years ago. The Ras-Raf-mitogen-activated protein kinase/extracellular signal-regulated kinase kinase-extracellular signal-regulated kinase/mitogen-activated protein kinase (Ras-Raf-MEK-ERK/MAPK) signaling pathway is at the heart of the signaling networks that control many fundamental cellular processes and Raf kinases takes centre stage in the MAPK pathway, which is now appreciated to be one of the most common sources of the oncogenic mutations in cancer. The dependency of tumors on this pathway has been clearly demonstrated by targeting its key nodes; however, blockade of the central components of the MAPK pathway may have some unexpected side effects. Over recent years, the Raf-interactome or Raf-interacting proteins have emerged as promising targets for protein-directed cancer therapy. This review focuses on the diversity of Raf-interacting proteins and discusses the mechanisms by which these proteins regulate Raf function, as well as the implications of targeting Raf-interacting proteins in the treatment of human cancer.
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Affiliation(s)
- Su An
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan, China
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22
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Nyman E, Rajan MR, Fagerholm S, Brännmark C, Cedersund G, Strålfors P. A single mechanism can explain network-wide insulin resistance in adipocytes from obese patients with type 2 diabetes. J Biol Chem 2014; 289:33215-30. [PMID: 25320095 DOI: 10.1074/jbc.m114.608927] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The response to insulin is impaired in type 2 diabetes. Much information is available about insulin signaling, but understanding of the cellular mechanisms causing impaired signaling and insulin resistance is hampered by fragmented data, mainly obtained from different cell lines and animals. We have collected quantitative and systems-wide dynamic data on insulin signaling in primary adipocytes and compared cells isolated from healthy and diabetic individuals. Mathematical modeling and experimental verification identified mechanisms of insulin control of the MAPKs ERK1/2. We found that in human adipocytes, insulin stimulates phosphorylation of the ribosomal protein S6 and hence protein synthesis about equally via ERK1/2 and mTORC1. Using mathematical modeling, we examined the signaling network as a whole and show that a single mechanism can explain the insulin resistance of type 2 diabetes throughout the network, involving signaling both through IRS1, PKB, and mTOR and via ERK1/2 to the nuclear transcription factor Elk1. The most important part of the insulin resistance mechanism is an attenuated feedback from the protein kinase mTORC1 to IRS1, which spreads signal attenuation to all parts of the insulin signaling network. Experimental inhibition of mTORC1 using rapamycin in adipocytes from non-diabetic individuals induced and thus confirmed the predicted network-wide insulin resistance.
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Affiliation(s)
- Elin Nyman
- From the Department of Clinical and Experimental Medicine and
| | | | - Siri Fagerholm
- From the Department of Clinical and Experimental Medicine and
| | | | - Gunnar Cedersund
- From the Department of Clinical and Experimental Medicine and the Department of Biomedical Engineering, Linköping University, SE58185 Linköping, Sweden
| | - Peter Strålfors
- From the Department of Clinical and Experimental Medicine and
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23
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Zhang Y, Zhan Y, Zhang D, Dai B, Ma W, Qi J, Liu R, He L. Eupolyphaga sinensis walker displays inhibition on hepatocellular carcinoma through regulating cell growth and metastasis signaling. Sci Rep 2014; 4:5518. [PMID: 24980220 PMCID: PMC4076680 DOI: 10.1038/srep05518] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 06/13/2014] [Indexed: 11/09/2022] Open
Abstract
Tumor growth and metastasis are responsible for most cancer patients' deaths. Here, we report that eupolyphaga sinensis walker has an essential role in resisting hepatocellular carcinoma growth and metastasis. Compared with proliferation, colony formation, transwell assay and transplantable tumor in nude mouse in vitro and vivo, eupolyphaga sinensis walker extract (ESWE) showed good inhibition on the SMMC-7721 cell growth and metastasis. Using genome-wide microarray analysis, we found the down-regulated growth and metastasis factors, and selected down-regulated genes were confirmed by real-time PCR. Knockdown of a checkpoint PKCβ by siRNA significantly attenuated tumor inhibition and metastasis effects of ESWE. Moreover, our results indicate ESWE inhibits HCC growth by not only downregulating the signaling of PKCβ, Akt, m-TOR, Erk1/2, MEK-2, Raf and JNK-1, but also increasing cyclin D1 protein levels and decreasing amount of cyclin E, cyclin B1 and cdc2 of the cycle proteins. At the same time, ESWE reduced MMP2, MMP9 and CXCR4, PLG, NFκB and P53 activities. Overall, our studies demonstrate that ESWE is a key factor in growth and metastasis signaling inhibitor targeting the PKC, AKT, MAPK signaling and related metastasis signaling, having potential in cancer therapy.
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Affiliation(s)
- Yanmin Zhang
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Yingzhuan Zhan
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Dongdong Zhang
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Bingling Dai
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Weina Ma
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Junpeng Qi
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Rui Liu
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
| | - Langchong He
- School of Pharmacy, Health Science Center, Xi'an Jiaotong University, Xi'an, Shaanxi Province, P.R. China
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24
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"RAF" neighborhood: protein-protein interaction in the Raf/Mek/Erk pathway. FEBS Lett 2014; 588:2398-406. [PMID: 24937142 PMCID: PMC4099524 DOI: 10.1016/j.febslet.2014.06.025] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 06/05/2014] [Accepted: 06/06/2014] [Indexed: 12/19/2022]
Abstract
The Raf/Mek/Erk signaling pathway, activated downstream of Ras primarily to promote proliferation, represents the best studied of the evolutionary conserved MAPK cascades. The investigation of the pathway has continued unabated since its discovery roughly 30 years ago. In the last decade, however, the identification of unexpected in vivo functions of pathway components, as well as the discovery of Raf mutations in human cancer, the ensuing quest for inhibitors, and the efforts to understand their mechanism of action, have boosted interest tremendously. From this large body of work, protein-protein interaction has emerged as a recurrent, crucial theme. This review focuses on the role of protein complexes in the regulation of the Raf/Mek/Erk pathway and in its cross-talk with other signaling cascades. Mapping these interactions and finding a way of exploiting them for therapeutic purposes is one of the challenges of future molecule-targeted therapy.
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25
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Najafi A, Bidkhori G, Bozorgmehr JH, Koch I, Masoudi-Nejad A. Genome scale modeling in systems biology: algorithms and resources. Curr Genomics 2014; 15:130-59. [PMID: 24822031 PMCID: PMC4009841 DOI: 10.2174/1389202915666140319002221] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 02/16/2014] [Accepted: 03/17/2014] [Indexed: 12/18/2022] Open
Abstract
In recent years, in silico studies and trial simulations have complemented experimental procedures. A model is a description of a system, and a system is any collection of interrelated objects; an object, moreover, is some elemental unit upon which observations can be made but whose internal structure either does not exist or is ignored. Therefore, any network analysis approach is critical for successful quantitative modeling of biological systems. This review highlights some of most popular and important modeling algorithms, tools, and emerging standards for representing, simulating and analyzing cellular networks in five sections. Also, we try to show these concepts by means of simple example and proper images and graphs. Overall, systems biology aims for a holistic description and understanding of biological processes by an integration of analytical experimental approaches along with synthetic computational models. In fact, biological networks have been developed as a platform for integrating information from high to low-throughput experiments for the analysis of biological systems. We provide an overview of all processes used in modeling and simulating biological networks in such a way that they can become easily understandable for researchers with both biological and mathematical backgrounds. Consequently, given the complexity of generated experimental data and cellular networks, it is no surprise that researchers have turned to computer simulation and the development of more theory-based approaches to augment and assist in the development of a fully quantitative understanding of cellular dynamics.
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Affiliation(s)
- Ali Najafi
- Laboratory of Systems Biology and Bioinformatics (LBB), Institute of Biochemistry and Biophysics, University of Tehran, Iran
| | - Gholamreza Bidkhori
- Laboratory of Systems Biology and Bioinformatics (LBB), Institute of Biochemistry and Biophysics, University of Tehran, Iran
| | - Joseph H. Bozorgmehr
- Laboratory of Systems Biology and Bioinformatics (LBB), Institute of Biochemistry and Biophysics, University of Tehran, Iran
| | - Ina Koch
- Molecular Bioinformatics, Johann Wolfgang Goethe-University Frankfurt am Main, Germany
| | - Ali Masoudi-Nejad
- Laboratory of Systems Biology and Bioinformatics (LBB), Institute of Biochemistry and Biophysics, University of Tehran, Iran
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Mazalouskas MD, Godoy-Ruiz R, Weber DJ, Zimmer DB, Honkanen RE, Wadzinski BE. Small G proteins Rac1 and Ras regulate serine/threonine protein phosphatase 5 (PP5)·extracellular signal-regulated kinase (ERK) complexes involved in the feedback regulation of Raf1. J Biol Chem 2013; 289:4219-32. [PMID: 24371145 DOI: 10.1074/jbc.m113.518514] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Serine/threonine protein phosphatase 5 (PP5, PPP5C) is known to interact with the chaperonin heat shock protein 90 (HSP90) and is involved in the regulation of multiple cellular signaling cascades that control diverse cellular processes, such as cell growth, differentiation, proliferation, motility, and apoptosis. Here, we identify PP5 in stable complexes with extracellular signal-regulated kinases (ERKs). Studies using mutant proteins reveal that the formation of PP5·ERK1 and PP5·ERK2 complexes partially depends on HSP90 binding to PP5 but does not require PP5 or ERK1/2 activity. However, PP5 and ERK activity regulates the phosphorylation state of Raf1 kinase, an upstream activator of ERK signaling. Whereas expression of constitutively active Rac1 promotes the assembly of PP5·ERK1/2 complexes, acute activation of ERK1/2 fails to influence the phosphatase-kinase interaction. Introduction of oncogenic HRas (HRas(V12)) has no effect on PP5-ERK1 binding but selectively decreases the interaction of PP5 with ERK2, in a manner that is independent of PP5 and MAPK/ERK kinase (MEK) activity, yet paradoxically requires ERK2 activity. Additional studies conducted with oncogenic variants of KRas4B reveal that KRas(L61), but not KRas(V12), also decreases the PP5-ERK2 interaction. The expression of wild type HRas or KRas proteins fails to reduce PP5-ERK2 binding, indicating that the effect is specific to HRas(V12) and KRas(L61) gain-of-function mutations. These findings reveal a novel, differential responsiveness of PP5-ERK1 and PP5-ERK2 interactions to select oncogenic Ras variants and also support a role for PP5·ERK complexes in regulating the feedback phosphorylation of PP5-associated Raf1.
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Affiliation(s)
- Matthew D Mazalouskas
- From the Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6600
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Lito P, Rosen N, Solit DB. Tumor adaptation and resistance to RAF inhibitors. Nat Med 2013; 19:1401-9. [DOI: 10.1038/nm.3392] [Citation(s) in RCA: 446] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 10/07/2013] [Indexed: 12/12/2022]
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Luo W, Wang X, Zheng L, Zhan Y, Zhang D, Zhang J, Zhang Y. Brucine suppresses colon cancer cells growth via mediating KDR signalling pathway. J Cell Mol Med 2013; 17:1316-24. [PMID: 23905676 PMCID: PMC4159018 DOI: 10.1111/jcmm.12108] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 07/01/2013] [Indexed: 01/30/2023] Open
Abstract
Angiogenesis plays an important role in colon cancer development. This study aimed to demonstrate the effect of brucine on tumour angiogenesis and its mechanism of action. The anti-angiogenic effect was evaluated on the chicken chorioallantoic membrane (CAM) model and tube formation. The mechanism was demonstrated through detecting mRNA and protein expressions of VEGFR2 (KDR), PKCα, PLCγ and Raf1 by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot (WB), as well as expressions of VEGF and PKCβ and mTOR by ELISA and WB. The results showed that brucine significantly reduced angiogenesis of CAM and tube formation, inhibited the VEGF secretion and mTOR expression in LoVo cell and down-regulated the mRNA and phosphorylation protein expressions of KDR, PKCα, PLCγ and Raf1. In addition, the effects of brucine on KDR kinase activity, viability of LoVo cell and gene knockdown cell were detected with the Lance™ assay, WST-1 assay and instantaneous siRNA. Compared to that of normal LoVo cells, the inhibition on proliferation of knockdown cells by brucine decreased significantly. These results suggest that brucine could inhibit angiogenesis and be a useful therapeutic candidate for colon cancer intervention.
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Affiliation(s)
- Wenjuan Luo
- School of Medicine, Xi'an Jiaotong UniversityXi'an, Shaanxi Province, China
| | - Xiaoli Wang
- School of Medicine, Xi'an Jiaotong UniversityXi'an, Shaanxi Province, China
| | - Lei Zheng
- School of Medicine, Xi'an Jiaotong UniversityXi'an, Shaanxi Province, China
| | - Yingzhuan Zhan
- School of Medicine, Xi'an Jiaotong UniversityXi'an, Shaanxi Province, China
| | - Dongdong Zhang
- School of Medicine, Xi'an Jiaotong UniversityXi'an, Shaanxi Province, China
| | - Jie Zhang
- School of Medicine, Xi'an Jiaotong UniversityXi'an, Shaanxi Province, China
| | - Yanmin Zhang
- School of Medicine, Xi'an Jiaotong UniversityXi'an, Shaanxi Province, China
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29
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Activation of a cyclic amp-guanine exchange factor in hepatocytes decreases nitric oxide synthase expression. Shock 2013; 39:70-6. [PMID: 23143065 DOI: 10.1097/shk.0b013e3182760530] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Adenosine 3',5'-cyclic adenosine monophosphate (cAMP) activates intracellular signaling by regulating protein kinase A, calcium influx, and cAMP-binging guanine nucleotide exchange factors (Epac [exchange protein directly activated by cAMP] or cAMP-GEF). Cyclic adenosine monophosphate inhibits cytokine-induced expression of inducible nitric oxide synthase (iNOS) in hepatocytes by a protein kinase A-independent mechanism. We hypothesized that Epac mediates this effect. A cyclic AMP analog that specifically activates Epac, 8-(4-methoxyphenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (OPTmecAMP), and overexpression of liver-specific Epac2 both inhibited interleukin 1β/interferon γ-induced iNOS expression and nitrite production. OPTmecAMP inactivated Raf1/MEK/ERK signaling, but ERK had no effect on iNOS expression. OPTmecAMP induced a persistent Akt phosphorylation in hepatocytes that lasted up to 8 h. Overexpression of a dominant-negative Akt blocked the inhibitory effect of OPTmecAMP on iNOS production. A specific PI3K inhibitor, LY294002, attenuated the inhibition of nitrite production and iNOS expression produced by overexpressing a liver-specific Epac2 (LEpac2). OPTmecAMP also induced c-Jun N-terminal kinase (JNK) phosphorylation in hepatocytes. Overexpression of dominant-negative JNK enhanced cytokine-induced iNOS expression and nitrite production and reversed the inhibitory effects of LEpac2 on nitrite production and iNOS expression. We conclude that Epac regulates hepatocyte iNOS expression through an Akt- and JNK-mediated signaling mechanism.
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Jensen HA, Styskal LE, Tasseff R, Bunaciu RP, Congleton J, Varner JD, Yen A. The Src-family kinase inhibitor PP2 rescues inducible differentiation events in emergent retinoic acid-resistant myeloblastic leukemia cells. PLoS One 2013; 8:e58621. [PMID: 23554907 PMCID: PMC3598855 DOI: 10.1371/journal.pone.0058621] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 02/05/2013] [Indexed: 12/29/2022] Open
Abstract
Retinoic acid is an embryonic morphogen and dietary factor that demonstrates chemotherapeutic efficacy in inducing maturation in leukemia cells. Using HL60 model human myeloid leukemia cells, where all-trans retinoic acid (RA) induces granulocytic differentiation, we developed two emergent RA-resistant HL60 cell lines which are characterized by loss of RA-inducible G1/G0 arrest, CD11b expression, inducible oxidative metabolism and p47phox expression. However, RA-treated RA-resistant HL60 continue to exhibit sustained MEK/ERK activation, and one of the two sequentially emergent resistant lines retains RA-inducible CD38 expression. Other signaling events that define the wild-type (WT) response are compromised, including c-Raf phosphorylation and increased expression of c-Cbl, Vav1, and the Src-family kinases (SFKs) Lyn and Fgr. As shown previously in WT HL60 cells, we found that the SFK inhibitor PP2 significantly increases G1/G0 cell cycle arrest, CD38 and CD11b expression, c-Raf phosphorylation and expression of the aforementioned regulators in RA-resistant HL60. The resistant cells were potentially incapable of developing inducible oxidative metabolism. These results motivate the concept that RA resistance can occur in steps, wherein growth arrest and other differentiation events may be recovered in both emergent lines. Investigating the mechanistic anomalies in resistant cell lines is of therapeutic significance and helps to mechanistically understand the response to retinoic acid’s biological effects in WT HL60 cells.
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Affiliation(s)
- Holly A. Jensen
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York, United States of America
| | - Lauren E. Styskal
- Department of Biological Engineering, Cornell University, Ithaca, New York, United States of America
| | - Ryan Tasseff
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York, United States of America
| | - Rodica P. Bunaciu
- Department of Biomedical Sciences, Cornell University, Ithaca, New York, United States of America
| | - Johanna Congleton
- Department of Biomedical Sciences, Cornell University, Ithaca, New York, United States of America
| | - Jeffrey D. Varner
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York, United States of America
| | - Andrew Yen
- Department of Biomedical Sciences, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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MEK-1 activates C-Raf through a Ras-independent mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:976-86. [PMID: 23360980 DOI: 10.1016/j.bbamcr.2013.01.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 12/29/2012] [Accepted: 01/15/2013] [Indexed: 12/16/2022]
Abstract
C-Raf is a member of the Ras-Raf-MEK-ERK mitogen-activated protein kinase (MAPK) signaling pathway that plays key roles in diverse physiological processes and is upregulated in many human cancers. C-Raf activation involves binding to Ras, increased phosphorylation and interactions with co-factors. Here, we describe a Ras-independent in vivo pathway for C-Raf activation by its downstream target MEK. Using (32)P-metabolic labeling and 2D-phosphopeptide mapping experiments, we show that MEK increases C-Raf phosphorylation by up-to 10-fold. This increase was associated with C-Raf kinase activation, matching the activity seen with growth factor stimulation. Consequently, coexpression of wildtype C-Raf and MEK was sufficient for full and constitutive activation of ERK. Notably, the ability of MEK to activate C-Raf was completely Ras independent, since mutants impaired in Ras binding that are irresponsive to growth factors or Ras were fully activated by MEK. The ability of MEK to activate C-Raf was only partially dependent on MEK kinase activity but required MEK binding to C-Raf, suggesting that the binding results in a conformational change that increases C-Raf susceptibility to phosphorylation and activation or in the stabilization of the phosphorylated-active form. These findings propose a novel Ras-independent mechanism for activating the C-Raf and the MAPK pathway without the need for mutations in the pathway. This mechanism could be of significance in pathological conditions or cancers overexpressing C-Raf and MEK or in conditions where C-Raf-MEK interaction is enhanced due to the down-regulation of RKIP and MST2.
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Albeck JG, Mills GB, Brugge JS. Frequency-modulated pulses of ERK activity transmit quantitative proliferation signals. Mol Cell 2012; 49:249-61. [PMID: 23219535 DOI: 10.1016/j.molcel.2012.11.002] [Citation(s) in RCA: 334] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2012] [Revised: 10/09/2012] [Accepted: 11/02/2012] [Indexed: 10/27/2022]
Abstract
The EGF-stimulated ERK/MAPK pathway is a key conduit for cellular proliferation signals and a therapeutic target in many cancers. Here, we characterize two central quantitative aspects of this pathway: the mechanism by which signal strength is encoded and the response curve relating signal output to proliferation. Under steady-state conditions, we find that ERK is activated in discrete, asynchronous pulses with frequency and duration determined by extracellular concentrations of EGF spanning the physiological range. In genetically identical sister cells, cell-to-cell variability in pulse dynamics influences the decision to enter S phase. While targeted inhibition of EGFR reduces the frequency of ERK activity pulses, inhibition of MEK reduces their amplitude. Continuous response curves measured in multiple cell lines reveal that proliferation is effectively silenced only when ERK pathway output falls below a threshold of ~10%, indicating that high-dose targeting of the pathway is necessary to achieve therapeutic efficacy.
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Affiliation(s)
- John G Albeck
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
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Bidkhori G, Moeini A, Masoudi-Nejad A. Modeling of tumor progression in NSCLC and intrinsic resistance to TKI in loss of PTEN expression. PLoS One 2012; 7:e48004. [PMID: 23133538 PMCID: PMC3483873 DOI: 10.1371/journal.pone.0048004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Accepted: 09/19/2012] [Indexed: 11/18/2022] Open
Abstract
EGFR signaling plays a very important role in NSCLC. It activates Ras/ERK, PI3K/Akt and STAT activation pathways. These are the main pathways for cell proliferation and survival. We have developed two mathematical models to relate to the different EGFR signaling in NSCLC and normal cells in the presence or absence of EGFR and PTEN mutations. The dynamics of downstream signaling pathways vary in the disease state and activation of some factors can be indicative of drug resistance. Our simulation denotes the effect of EGFR mutations and increased expression of certain factors in NSCLC EGFR signaling on each of the three pathways where levels of pERK, pSTAT and pAkt are increased. Over activation of ERK, Akt and STAT3 which are the main cell proliferation and survival factors act as promoting factors for tumor progression in NSCLC. In case of loss of PTEN, Akt activity level is considerably increased. Our simulation results show that in the presence of erlotinib, downstream factors i.e. pAkt, pSTAT3 and pERK are inhibited. However, in case of loss of PTEN expression in the presence of erlotinib, pAkt level would not decrease which demonstrates that these cells are resistant to erlotinib.
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Affiliation(s)
- Gholamreza Bidkhori
- Laboratory of Systems Biology and Bioinformatics (LBB), Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Ali Moeini
- Department of Algorithms and Computation, College of Engineering, University of Tehran, Tehran, Iran
| | - Ali Masoudi-Nejad
- Laboratory of Systems Biology and Bioinformatics (LBB), Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
- * E-mail:
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McCubrey JA, Steelman LS, Chappell WH, Abrams SL, Montalto G, Cervello M, Nicoletti F, Fagone P, Malaponte G, Mazzarino MC, Candido S, Libra M, Bäsecke J, Mijatovic S, Maksimovic-Ivanic D, Milella M, Tafuri A, Cocco L, Evangelisti C, Chiarini F, Martelli AM. Mutations and deregulation of Ras/Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR cascades which alter therapy response. Oncotarget 2012; 3:954-87. [PMID: 23006971 PMCID: PMC3660063 DOI: 10.18632/oncotarget.652] [Citation(s) in RCA: 217] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 09/17/2012] [Indexed: 02/07/2023] Open
Abstract
The Ras/Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR cascades are often activated by genetic alterations in upstream signaling molecules such as receptor tyrosine kinases (RTK). Certain components of these pathways, RAS, NF1, BRAF, MEK1, DUSP5, PP2A, PIK3CA, PIK3R1, PIK3R4, PIK3R5, IRS4, AKT, NFKB1, MTOR, PTEN, TSC1, and TSC2 may also be activated/inactivated by mutations or epigenetic silencing. Upstream mutations in one signaling pathway or even in downstream components of the same pathway can alter the sensitivity of the cells to certain small molecule inhibitors. These pathways have profound effects on proliferative, apoptotic and differentiation pathways. Dysregulation of components of these cascades can contribute to: resistance to other pathway inhibitors, chemotherapeutic drug resistance, premature aging as well as other diseases. This review will first describe these pathways and discuss how genetic mutations and epigenetic alterations can result in resistance to various inhibitors.
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Affiliation(s)
- James A McCubrey
- Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University, Greenville, NC, USA.
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De La Garza EM, Binkley PA, Ganapathy M, Krishnegowda NK, Tekmal RR, Schenken RS, Kirma NB. Raf-1, a potential therapeutic target, mediates early steps in endometriosis lesion development by endometrial epithelial and stromal cells. Endocrinology 2012; 153:3911-21. [PMID: 22619359 DOI: 10.1210/en.2011-1879] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Endometriosis is a hormone-sensitive gynecological disorder characterized by the benign growth of endometrial-like tissue in the pelvic cavity. Endometriotic lesions composed of endometrial stromal cells (ESC) and glandular epithelial cells (EEC) are thought to arise from menstrual endometrial tissue reaching the pelvic cavity via retrograde menstruation. The cause of endometriotic lesion formation is still not clear. Recent evidence suggest that cytokines may play a role in the early development of endometriosis lesions. Because cytokines and growth factors signal via the v-raf-1 murine leukemia viral oncogene homolog 1 (Raf-1) kinase pathway, we have examined the role of Raf-1 in early steps of endometriosis lesion formation, specifically attachment of endometrial cells to peritoneal mesothelial cells (PMC) and invasion of endometrial cells through PMC (trans-mesothelial invasion). Raf-1 antagonist GW5074 decreased attachment to PMC and trans-mesothelial invasion by primary EEC and ESC. Raf-1 also mediated TGFβ-induced trans-mesothelial invasion by the established, low-invasive EEC line EM42. TGFβ treatment of EEC resulted in Raf-1 phosphorylation at S338 and phosphorylation of ERK, suggesting that TGFβ activates Raf-1 signaling in these cells. GW5074 had little effect on ESC proliferation but inhibited EEC growth significantly under reduced serum conditions. Antagonizing Raf-1 activity and expression via GW5074 and specific Raf-1 small interfering RNA, respectively, did not alter EEC resistance to growth inhibition by TGFβ. Raf-1 inhibition blocked induction of EEC growth by epidermal growth factor. Our data suggest that Raf-1 may mediate pathologic steps involved in early endometriosis lesion formation and may be a mediator of TGFβ and epidermal growth factor actions in endometriosis.
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Affiliation(s)
- Elizabeth M De La Garza
- Department of Obstetrics and Gynecology, University of Texas Health Science Centre at San Antonio, San Antonio, Texas 78229, USA
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Sarma U, Ghosh I. Oscillations in MAPK cascade triggered by two distinct designs of coupled positive and negative feedback loops. BMC Res Notes 2012; 5:287. [PMID: 22694947 PMCID: PMC3532088 DOI: 10.1186/1756-0500-5-287] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 04/30/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Feedback loops, both positive and negative are embedded in the Mitogen Activated Protein Kinase (MAPK) cascade. In the three layer MAPK cascade, both feedback loops originate from the terminal layer and their sites of action are either of the two upstream layers. Recent studies have shown that the cascade uses coupled positive and negative feedback loops in generating oscillations. Two plausible designs of coupled positive and negative feedback loops can be elucidated from the literature; in one design the positive feedback precedes the negative feedback in the direction of signal flow and vice-versa in another. But it remains unexplored how the two designs contribute towards triggering oscillations in MAPK cascade. Thus it is also not known how amplitude, frequency, robustness or nature (analogous/digital) of the oscillations would be shaped by these two designs. RESULTS We built two models of MAPK cascade that exhibited oscillations as function of two underlying designs of coupled positive and negative feedback loops. Frequency, amplitude and nature (digital/analogous) of oscillations were found to be differentially determined by each design. It was observed that the positive feedback emerging from an oscillating MAPK cascade and functional in an external signal processing module can trigger oscillations in the target module, provided that the target module satisfy certain parametric requirements. The augmentation of the two models was done to incorporate the nuclear-cytoplasmic shuttling of cascade components followed by induction of a nuclear phosphatase. It revealed that the fate of oscillations in the MAPK cascade is governed by the feedback designs. Oscillations were unaffected due to nuclear compartmentalization owing to one design but were completely abolished in the other case. CONCLUSION The MAPK cascade can utilize two distinct designs of coupled positive and negative feedback loops to trigger oscillations. The amplitude, frequency and robustness of the oscillations in presence or absence of nuclear compartmentalization were differentially determined by two designs of coupled positive and negative feedback loops. A positive feedback from an oscillating MAPK cascade was shown to induce oscillations in an external signal processing module, uncovering a novel regulatory aspect of MAPK signal processing.
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Affiliation(s)
- Uddipan Sarma
- National Centre for Cell Science, Ganeshkhind, Pune, India.
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Rangasamy V, Mishra R, Sondarva G, Das S, Lee TH, Bakowska JC, Tzivion G, Malter JS, Rana B, Lu KP, Kanthasamy A, Rana A. Mixed-lineage kinase 3 phosphorylates prolyl-isomerase Pin1 to regulate its nuclear translocation and cellular function. Proc Natl Acad Sci U S A 2012; 109:8149-54. [PMID: 22566623 PMCID: PMC3361382 DOI: 10.1073/pnas.1200804109] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Nuclear protein peptidyl-prolyl isomerase Pin1-mediated prolyl isomerization is an essential and novel regulatory mechanism for protein phosphorylation. Therefore, tight regulation of Pin1 localization and catalytic activity is crucial for its normal nuclear functions. Pin1 is commonly dysregulated during oncogenesis and likely contributes to these pathologies; however, the mechanism(s) by which Pin1 catalytic activity and nuclear localization are increased is unknown. Here we demonstrate that mixed-lineage kinase 3 (MLK3), a MAP3K family member, phosphorylates Pin1 on a Ser138 site to increase its catalytic activity and nuclear translocation. This phosphorylation event drives the cell cycle and promotes cyclin D1 stability and centrosome amplification. Notably, Pin1 pSer138 is significantly up-regulated in breast tumors and is localized in the nucleus. These findings collectively suggest that the MLK3-Pin1 signaling cascade plays a critical role in regulating the cell cycle, centrosome numbers, and oncogenesis.
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Affiliation(s)
| | | | | | - Subhasis Das
- Departments of Molecular Pharmacology and Therapeutics and
| | - Tae Ho Lee
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02115
| | | | - Guri Tzivion
- Cancer Institute, University of Mississippi Medical Center, Jackson, MS 39216
| | - James S. Malter
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI 53705
| | - Basabi Rana
- Medicine, Loyola University Chicago, Maywood, IL 60153
- Hines Veterans Affairs Medical Center, Hines, IL 60141; and
| | - Kun Ping Lu
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02115
| | - Anumantha Kanthasamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011
| | - Ajay Rana
- Departments of Molecular Pharmacology and Therapeutics and
- Hines Veterans Affairs Medical Center, Hines, IL 60141; and
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Rangel-Salazar R, Wickström-Lindholm M, Aguilar-Salinas CA, Alvarado-Caudillo Y, Døssing KBV, Esteller M, Labourier E, Lund G, Nielsen FC, Rodríguez-Ríos D, Solís-Martínez MO, Wrobel K, Wrobel K, Zaina S. Human native lipoprotein-induced de novo DNA methylation is associated with repression of inflammatory genes in THP-1 macrophages. BMC Genomics 2011; 12:582. [PMID: 22118513 PMCID: PMC3247910 DOI: 10.1186/1471-2164-12-582] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 11/25/2011] [Indexed: 01/31/2023] Open
Abstract
Background We previously showed that a VLDL- and LDL-rich mix of human native lipoproteins induces a set of repressive epigenetic marks, i.e. de novo DNA methylation, histone 4 hypoacetylation and histone 4 lysine 20 (H4K20) hypermethylation in THP-1 macrophages. Here, we: 1) ask what gene expression changes accompany these epigenetic responses; 2) test the involvement of candidate factors mediating the latter. We exploited genome expression arrays to identify target genes for lipoprotein-induced silencing, in addition to RNAi and expression studies to test the involvement of candidate mediating factors. The study was conducted in human THP-1 macrophages. Results Native lipoprotein-induced de novo DNA methylation was associated with a general repression of various critical genes for macrophage function, including pro-inflammatory genes. Lipoproteins showed differential effects on epigenetic marks, as de novo DNA methylation was induced by VLDL and to a lesser extent by LDL, but not by HDL, and VLDL induced H4K20 hypermethylation, while HDL caused H4 deacetylation. The analysis of candidate factors mediating VLDL-induced DNA hypermethylation revealed that this response was: 1) surprisingly, mediated exclusively by the canonical maintenance DNA methyltransferase DNMT1, and 2) independent of the Dicer/micro-RNA pathway. Conclusions Our work provides novel insights into epigenetic gene regulation by native lipoproteins. Furthermore, we provide an example of DNMT1 acting as a de novo DNA methyltransferase independently of canonical de novo enzymes, and show proof of principle that de novo DNA methylation can occur independently of a functional Dicer/micro-RNA pathway in mammals.
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Steelman LS, Chappell WH, Abrams SL, Kempf RC, Long J, Laidler P, Mijatovic S, Maksimovic-Ivanic D, Stivala F, Mazzarino MC, Donia M, Fagone P, Malaponte G, Nicoletti F, Libra M, Milella M, Tafuri A, Bonati A, Bäsecke J, Cocco L, Evangelisti C, Martelli AM, Montalto G, Cervello M, McCubrey JA. Roles of the Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR pathways in controlling growth and sensitivity to therapy-implications for cancer and aging. Aging (Albany NY) 2011; 3:192-222. [PMID: 21422497 PMCID: PMC3091517 DOI: 10.18632/aging.100296] [Citation(s) in RCA: 457] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Dysregulated signaling through the Ras/Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR pathways is often the result of genetic alterations in critical components in these pathways or upstream activators. Unrestricted cellular proliferation and decreased sensitivity to apoptotic-inducing agents are typically associated with activation of these pro-survival pathways. This review discusses the functions these pathways have in normal and neoplastic tissue growth and how they contribute to resistance to apoptotic stimuli. Crosstalk and commonly identified mutations that occur within these pathways that contribute to abnormal activation and cancer growth will also be addressed. Finally the recently described roles of these pathways in cancer stem cells, cellular senescence and aging will be evaluated. Controlling the expression of these pathways could ameliorate human health.
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Affiliation(s)
- Linda S Steelman
- Department of Microbiology and Immunology, East Carolina University, Greenville, NC 27858, USA
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Abstract
The Ras/Raf/mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway is often implicated in sensitivity and resistance to leukemia therapy. Dysregulated signaling through the Ras/Raf/MEK/ERK pathway is often the result of genetic alterations in critical components in this pathway as well as mutations at upstream growth factor receptors. Unrestricted leukemia proliferation and decreased sensitivity to apoptotic-inducing agents and chemoresistance are typically associated with activation of pro-survival pathways. Mutations in this pathway and upstream signaling molecules can alter sensitivity to small molecule inhibitors targeting components of this cascade as well as to inhibitors targeting other key pathways (for example, phosphatidylinositol 3 kinase (PI3K)/phosphatase and tensin homologue deleted on chromosome 10 (PTEN)/Akt/mammalian target of rapamycin (mTOR)) activated in leukemia. Similarly, PI3K mutations can result in resistance to inhibitors targeting the Ras/Raf/MEK/ERK pathway, indicating important interaction points between the pathways (cross-talk). Furthermore, the Ras/Raf/MEK/ERK pathway can be activated by chemotherapeutic drugs commonly used in leukemia therapy. This review discusses the mechanisms by which abnormal expression of the Ras/Raf/MEK/ERK pathway can contribute to drug resistance as well as resistance to targeted leukemia therapy. Controlling the expression of this pathway could improve leukemia therapy and ameliorate human health.
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Matallanas D, Birtwistle M, Romano D, Zebisch A, Rauch J, von Kriegsheim A, Kolch W. Raf family kinases: old dogs have learned new tricks. Genes Cancer 2011; 2:232-60. [PMID: 21779496 PMCID: PMC3128629 DOI: 10.1177/1947601911407323] [Citation(s) in RCA: 272] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
First identified in the early 1980s as retroviral oncogenes, the Raf proteins have been the objects of intense research. The discoveries 10 years later that the Raf family members (Raf-1, B-Raf, and A-Raf) are bona fide Ras effectors and upstream activators of the ubiquitous ERK pathway increased the interest in these proteins primarily because of the central role that this cascade plays in cancer development. The important role of Raf in cancer was corroborated in 2002 with the discovery of B-Raf genetic mutations in a large number of tumors. This led to intensified drug development efforts to target Raf signaling in cancer. This work yielded not only recent clinical successes but also surprising insights into the regulation of Raf proteins by homodimerization and heterodimerization. Surprising insights also came from the hunt for new Raf targets. Although MEK remains the only widely accepted Raf substrate, new kinase-independent roles for Raf proteins have emerged. These include the regulation of apoptosis by suppressing the activity of the proapoptotic kinases, ASK1 and MST2, and the regulation of cell motility and differentiation by controlling the activity of Rok-α. In this review, we discuss the regulation of Raf proteins and their role in cancer, with special focus on the interacting proteins that modulate Raf signaling. We also describe the new pathways controlled by Raf proteins and summarize the successes and failures in the development of efficient anticancer therapies targeting Raf. Finally, we also argue for the necessity of more systemic approaches to obtain a better understanding of how the Ras-Raf signaling network generates biological specificity.
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Affiliation(s)
- David Matallanas
- Systems Biology Ireland, University College Dublin, Dublin, Ireland
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42
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Udell CM, Rajakulendran T, Sicheri F, Therrien M. Mechanistic principles of RAF kinase signaling. Cell Mol Life Sci 2011; 68:553-65. [PMID: 20820846 PMCID: PMC11114552 DOI: 10.1007/s00018-010-0520-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 08/24/2010] [Accepted: 08/25/2010] [Indexed: 12/19/2022]
Abstract
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 the phosphoryl transfer reaction. This transition involves changes both within and between the protein domains in RAF. Many different proteins regulate the transition between inactive and active states of RAF, including RAS and KSR, which are arguably the two most prominent regulators of RAF function. Recent developments have added several new twists to our understanding of RAF regulation. Among others, dimerization of the RAF kinase domain is emerging as a crucial step in the RAF activation process. The multitude of regulatory protein-protein interactions involving RAF remains a largely untapped area for therapeutic applications.
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Affiliation(s)
- Christian M. Udell
- Laboratory of Intracellular Signaling, Département de pathologie et de biologie cellulaire, Institute for Research in Immunology and Cancer, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montreal, QC H3C 3J7 Canada
| | - Thanashan Rajakulendran
- Centre for Systems Biology, Samuel Lunenfeld Research Institute, Toronto, ON M5G 1X5 Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8 Canada
| | - Frank Sicheri
- Centre for Systems Biology, Samuel Lunenfeld Research Institute, Toronto, ON M5G 1X5 Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8 Canada
| | - Marc Therrien
- Laboratory of Intracellular Signaling, Département de pathologie et de biologie cellulaire, Institute for Research in Immunology and Cancer, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montreal, QC H3C 3J7 Canada
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Jung KH, Cao P, Seo YS, Dardick C, Ronald PC. The Rice Kinase Phylogenomics Database: a guide for systematic analysis of the rice kinase super-family. TRENDS IN PLANT SCIENCE 2010; 15:595-9. [PMID: 20832349 DOI: 10.1016/j.tplants.2010.08.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 07/27/2010] [Accepted: 08/12/2010] [Indexed: 05/06/2023]
Abstract
Determination of gene function is particularly problematic when studying large-gene families because redundancy limits the ability to assess the contributions of individual genes experimentally. Phylogenomics is a phylogenetic approach used in comparative genomics to predict the biological functions of members of large gene-families by assessing the similarity among gene products. In this report, we describe the application of the Rice Kinase Database for elucidating functions of individual members of this gene family.
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Affiliation(s)
- Ki-Hong Jung
- Department of Plant Pathology, University of California, Davis, CA 95616, USA
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McCubrey JA, Abrams SL, Stadelman K, Chappell WH, Lahair M, Ferland RA, Steelman LS. Targeting signal transduction pathways to eliminate chemotherapeutic drug resistance and cancer stem cells. ADVANCES IN ENZYME REGULATION 2009; 50:285-307. [PMID: 19895837 PMCID: PMC2862855 DOI: 10.1016/j.advenzreg.2009.10.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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McCubrey JA, Steelman LS, Abrams SL, Chappell WH, Russo S, Ove R, Milella M, Tafuri A, Lunghi P, Bonati A, Stivala F, Nicoletti F, Libra M, Martelli AM, Montalto G, Cervello M. Emerging Raf inhibitors. Expert Opin Emerg Drugs 2009; 14:633-48. [DOI: 10.1517/14728210903232633] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Yasuda S, Kai M, Imai SI, Takeishi K, Taketomi A, Toyota M, Kanoh H, Sakane F. Diacylglycerol kinase eta augments C-Raf activity and B-Raf/C-Raf heterodimerization. J Biol Chem 2009; 284:29559-70. [PMID: 19710016 DOI: 10.1074/jbc.m109.043604] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Ras/B-Raf/C-Raf/MEK/ERK signaling cascade is critical for the control of many fundamental cellular processes, including proliferation, survival, and differentiation. This study demonstrated that small interfering RNA-dependent knockdown of diacylglycerol kinase eta (DGKeta) impaired the Ras/B-Raf/C-Raf/MEK/ERK pathway activated by epidermal growth factor (EGF) in HeLa cells. Conversely, the overexpression of DGKeta1 could activate the Ras/B-Raf/C-Raf/MEK/ERK pathway in a DGK activity-independent manner, suggesting that DGKeta serves as a scaffold/adaptor protein. By determining the activity of all the components of the pathway in DGKeta-silenced HeLa cells, this study revealed that DGKeta activated C-Raf but not B-Raf. Moreover, this study demonstrated that DGKeta enhanced EGF-induced heterodimerization of C-Raf with B-Raf, which transmits the signal to C-Raf. DGKeta physically interacted with B-Raf and C-Raf, regulating EGF-induced recruitment of B-Raf and C-Raf from the cytosol to membranes. The DGKeta-dependent activation of C-Raf occurred downstream or independently of the already known C-Raf modifications, such as dephosphorylation at Ser-259, phosphorylation at Ser-338, and interaction with 14-3-3 protein. Taken together, the results obtained strongly support that DGKeta acts as a novel critical regulatory component of the Ras/B-Raf/C-Raf/MEK/ERK signaling cascade via a previously unidentified mechanism.
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Affiliation(s)
- Satoshi Yasuda
- Department of Biochemistry, Sapporo Medical University School of Medicine, South-1, West-17, Chuo-ku, Sapporo 060-8556
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Singh-Gupta V, Zhang H, Banerjee S, Kong D, Raffoul JJ, Sarkar FH, Hillman GG. Radiation-induced HIF-1alpha cell survival pathway is inhibited by soy isoflavones in prostate cancer cells. Int J Cancer 2009; 124:1675-84. [PMID: 19101986 PMCID: PMC2670478 DOI: 10.1002/ijc.24015] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We previously showed that treatment of prostate cancer cells with soy isoflavones and radiation resulted in greater cell killing in vitro, and caused downregulation of NF-kappaB and APE1/Ref-1. APE1/Ref-1 functions as a redox activator of transcription factors, including NF-kappaB and HIF-1alpha. These molecules are upregulated by radiation and implicated in radioresistance of cancer cells. We extended our studies to investigate the role of HIF-1alpha survival pathway and its upstream Src and STAT3 molecules in isoflavones and radiation interaction. Radiation induced phosphorylation of Src and STAT3 leading to induction of HIF-1alpha. Genistein, daidzein or a mixture of soy isoflavones did not activate this pathway. These data were observed both in PC-3 (AR-) and C4-2B (AR+) androgen-independent cell lines. Pretreatment with isoflavones inhibited Src/STAT3/HIF-1alpha activation by radiation and nuclear translocation of HIF-1alpha. These findings correlated with decreased expression of APE1/Ref-1 and DNA binding activity of HIF-1alpha and NF-kappaB. In APE1/Ref-1 cDNA transfected cells, radiation caused a greater increase in HIF-1alpha and NF-kappaB activities but this effect was inhibited by pretreatment with soy prior to radiation. Transfection experiments indicate that APE1/Ref-1 inhibition by isoflavones impairs the radiation-induced transcription activity of NF-kappaB and HIF-1alpha. This mechanism could result in the inhibition of genes essential for tumor growth and angiogenesis, as demonstrated by inhibition of VEGF production and HUVECs tube formation. Our novel findings suggest that the increased responsiveness to radiation mediated by soy isoflavones could be due to pleiotropic effects of isoflavones blocking cell survival pathways induced by radiation including Src/STAT3/HIF-1alpha, APE1/Ref-1 and NF-kappaB.
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Affiliation(s)
- Vinita Singh-Gupta
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Hao Zhang
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Sanjeev Banerjee
- Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Dejuan Kong
- Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Julian J. Raffoul
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Fazlul H. Sarkar
- Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Gilda G. Hillman
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
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Smolen P, Baxter DA, Byrne JH. Interlinked dual-time feedback loops can enhance robustness to stochasticity and persistence of memory. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:031902. [PMID: 19391966 PMCID: PMC2742492 DOI: 10.1103/physreve.79.031902] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Revised: 01/09/2009] [Indexed: 05/27/2023]
Abstract
Multiple interlinked positive feedback loops shape the stimulus responses of various biochemical systems, such as the cell cycle or intracellular Ca2+ release. Recent studies with simplified models have identified two advantages of coupling fast and slow feedback loops. This dual-time structure enables a fast response while enhancing resistances of responses and bistability to stimulus noise. We now find that (1) the dual-time structure similarly confers resistance to internal noise due to molecule number fluctuations, and (2) model variants with altered coupling, which better represent some specific biochemical systems, share all the above advantages. We also develop a similar bistable model with coupling of a fast autoactivation loop to a slow loop. This model's topology was suggested by positive feedback proposed to play a role in long-term synaptic potentiation (LTP). The advantages of fast response and noise resistance are also present in this autoactivation model. Empirically, LTP develops resistance to reversal over approximately 1h . The model suggests this resistance may result from increased amounts of synaptic kinases involved in positive feedback.
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Affiliation(s)
- Paul Smolen
- Department of Neurobiology and Anatomy, W.M. Keck Center for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, P.O. Box 20708, Houston, Texas 77225, USA
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50
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Han S, Meier KE. Integrated modulation of phorbol ester-induced Raf activation in EL4 lymphoma cells. Cell Signal 2009; 21:793-800. [PMID: 19263515 DOI: 10.1016/j.cellsig.2009.01.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The EL4 murine lymphoma cell line exists in variant phenotypes that differ with respect to responses to the tumor promoter phorbol 12-myristate 13-acetate (PMA1). Previous work showed that "PMA-sensitive" cells, characterized by a high magnitude of PMA-induced Erk activation, express RasGRP, a phorbol ester receptor that directly activates Ras. In "PMA-resistant" and "intermediate" EL4 cell lines, PMA induces Erk activation to lesser extents, but with a greater response in intermediate cells. In the current study, these cell lines were used to examine mechanisms of Raf-1 modulation. Phospho-specific antibodies were utilized to define patterns and kinetics of Raf-1 phosphorylation on several sites. Further studies showed that Akt is constitutively activated to a greater extent in PMA-resistant than in PMA-sensitive cells, and also to a greater extent in resistant than intermediate cells. Akt negatively regulates Raf-1 activation (Ser259), partially explaining the difference between resistant and intermediate cells. Erk activation exerts negative feedback on Raf-1 (Ser289/296/301), thus resulting in earlier termination of the signal in cells with a higher level of Erk activation. RKIP, a Raf inhibitory protein, is expressed at higher levels in resistant cells than in sensitive or intermediate cells. Knockdown of RKIP increases Erk activation and also negative feedback. In conclusion, this study delineates Raf-1 phosphorylation events occurring in response to PMA in cell lines with different extents of Erk activation. Variations in the levels of expression and activation of multiple signaling proteins work in an integrated fashion to modulate the extent and duration of Erk activation.
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Affiliation(s)
- Shujie Han
- Department of Pharmaceutical Sciences, Washington State University, Pullman, Washington 99164-6534, United States
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