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Mehrabipour M, Nakhaei-Rad S, Dvorsky R, Lang A, Verhülsdonk P, Ahmadian MR, Piekorz RP. SIRT4 as a novel interactor and candidate suppressor of C-RAF kinase in MAPK signaling. Life Sci Alliance 2024; 7:e202302507. [PMID: 38499327 PMCID: PMC10948936 DOI: 10.26508/lsa.202302507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 03/06/2024] [Accepted: 03/07/2024] [Indexed: 03/20/2024] Open
Abstract
Cellular responses leading to development, proliferation, and differentiation depend on RAF/MEK/ERK signaling, which integrates and amplifies signals from various stimuli for downstream cellular responses. C-RAF activation has been reported in many types of tumor cell proliferation and developmental disorders, necessitating the discovery of potential C-RAF protein regulators. Here, we identify a novel and specific protein interaction between C-RAF among the RAF kinase paralogs, and SIRT4 among the mitochondrial sirtuin family members SIRT3, SIRT4, and SIRT5. Structurally, C-RAF binds to SIRT4 through the N-terminal cysteine-rich domain, whereas SIRT4 predominantly requires the C-terminus for full interaction with C-RAF. Interestingly, SIRT4 specifically interacts with C-RAF in a pre-signaling inactive (serine 259-phosphorylated) state. Consistent with this finding, the expression of SIRT4 in HEK293 cells results in an up-regulation of pS259-C-RAF levels and a concomitant reduction in MAPK signaling as evidenced by strongly decreased phospho-ERK signals. Thus, we propose an additional extra-mitochondrial function of SIRT4 as a cytosolic tumor suppressor of C-RAF-MAPK signaling, besides its metabolic tumor suppressor role of glutamate dehydrogenase and glutamate levels in mitochondria.
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Affiliation(s)
- Mehrnaz Mehrabipour
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Saeideh Nakhaei-Rad
- Stem Cell Biology, and Regenerative Medicine Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Radovan Dvorsky
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Alexander Lang
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Patrick Verhülsdonk
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Mohammad R Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Roland P Piekorz
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, 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: 0] [Impact Index Per Article: 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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Bahar ME, Kim HJ, Kim DR. Targeting the RAS/RAF/MAPK pathway for cancer therapy: from mechanism to clinical studies. Signal Transduct Target Ther 2023; 8:455. [PMID: 38105263 PMCID: PMC10725898 DOI: 10.1038/s41392-023-01705-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 11/03/2023] [Accepted: 11/12/2023] [Indexed: 12/19/2023] Open
Abstract
Metastatic dissemination of solid tumors, a leading cause of cancer-related mortality, underscores the urgent need for enhanced insights into the molecular and cellular mechanisms underlying metastasis, chemoresistance, and the mechanistic backgrounds of individuals whose cancers are prone to migration. The most prevalent signaling cascade governed by multi-kinase inhibitors is the mitogen-activated protein kinase (MAPK) pathway, encompassing the RAS-RAF-MAPK kinase (MEK)-extracellular signal-related kinase (ERK) pathway. RAF kinase is a primary mediator of the MAPK pathway, responsible for the sequential activation of downstream targets, such as MEK and the transcription factor ERK, which control numerous cellular and physiological processes, including organism development, cell cycle control, cell proliferation and differentiation, cell survival, and death. Defects in this signaling cascade are associated with diseases such as cancer. RAF inhibitors (RAFi) combined with MEK blockers represent an FDA-approved therapeutic strategy for numerous RAF-mutant cancers, including melanoma, non-small cell lung carcinoma, and thyroid cancer. However, the development of therapy resistance by cancer cells remains an important barrier. Autophagy, an intracellular lysosome-dependent catabolic recycling process, plays a critical role in the development of RAFi resistance in cancer. Thus, targeting RAF and autophagy could be novel treatment strategies for RAF-mutant cancers. In this review, we delve deeper into the mechanistic insights surrounding RAF kinase signaling in tumorigenesis and RAFi-resistance. Furthermore, we explore and discuss the ongoing development of next-generation RAF inhibitors with enhanced therapeutic profiles. Additionally, this review sheds light on the functional interplay between RAF-targeted therapies and autophagy in cancer.
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Affiliation(s)
- Md Entaz Bahar
- Department of Biochemistry and Convergence Medical Sciences and Institute of Medical Science, Gyeongsang National University, College of Medicine, Jinju, South Korea
| | - Hyun Joon Kim
- Department of Anatomy and Convergence Medical Sciences and Institute of Medical Science, Gyeongsang National University, College of Medicine, Jinju, South Korea
| | - Deok Ryong Kim
- Department of Biochemistry and Convergence Medical Sciences and Institute of Medical Science, Gyeongsang National University, College of Medicine, Jinju, South Korea.
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4
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Kirkbride JA, Nilsson GY, Kim JI, Takeya K, Tanaka Y, Tokumitsu H, Suizu F, Eto M. PHI-1, an Endogenous Inhibitor Protein for Protein Phosphatase-1 and a Pan-Cancer Marker, Regulates Raf-1 Proteostasis. Biomolecules 2023; 13:1741. [PMID: 38136612 PMCID: PMC10741526 DOI: 10.3390/biom13121741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 11/30/2023] [Accepted: 11/30/2023] [Indexed: 12/24/2023] Open
Abstract
Raf-1, a multifunctional kinase, regulates various cellular processes, including cell proliferation, apoptosis, and migration, by phosphorylating MAPK/ERK kinase and interacting with specific kinases. Cellular Raf-1 activity is intricately regulated through pathways involving the binding of regulatory proteins, direct phosphorylation, and the ubiquitin-proteasome axis. In this study, we demonstrate that PHI-1, an endogenous inhibitor of protein phosphatase-1 (PP1), plays a pivotal role in modulating Raf-1 proteostasis within cells. Knocking down endogenous PHI-1 in HEK293 cells using siRNA resulted in increased cell proliferation and reduced apoptosis. This heightened cell proliferation was accompanied by a 15-fold increase in ERK1/2 phosphorylation. Importantly, the observed ERK1/2 hyperphosphorylation was attributable to an upregulation of Raf-1 expression, rather than an increase in Ras levels, Raf-1 Ser338 phosphorylation, or B-Raf levels. The elevated Raf-1 expression, stemming from PHI-1 knockdown, enhanced EGF-induced ERK1/2 phosphorylation through MEK. Moreover, PHI-1 knockdown significantly contributed to Raf-1 protein stability without affecting Raf-1 mRNA levels. Conversely, ectopic PHI-1 expression suppressed Raf-1 protein levels in a manner that correlated with PHI-1's inhibitory potency. Inhibiting PP1 to mimic PHI-1's function using tautomycin led to a reduction in Raf-1 expression. In summary, our findings highlight that the PHI-1-PP1 signaling axis selectively governs Raf-1 proteostasis and cell survival signals.
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Affiliation(s)
- Jason A. Kirkbride
- Department of Molecular Physiology and Biophysics, and Kimmel Cancer Center, Jefferson Medical College, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
| | - Garbo Young Nilsson
- Department of Molecular Physiology and Biophysics, and Kimmel Cancer Center, Jefferson Medical College, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
| | - Jee In Kim
- Department of Molecular Physiology and Biophysics, and Kimmel Cancer Center, Jefferson Medical College, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
- Department of Molecular Medicine, Keimyung University School of Medicine, Daegu 42601, Republic of Korea
| | - Kosuke Takeya
- Department of Veterinary Medicine, Faculty of Veterinary Medicine, Okayama University of Science, Imabari 794-8555, Ehime, Japan (Y.T.)
| | - Yoshinori Tanaka
- Department of Veterinary Medicine, Faculty of Veterinary Medicine, Okayama University of Science, Imabari 794-8555, Ehime, Japan (Y.T.)
| | - Hiroshi Tokumitsu
- Applied Cell Biology, Graduate School of Interdisciplinary Science & Engineering in Health Systems, Okayama University, Okayama 700-8530, Okayama, Japan
| | - Futoshi Suizu
- Oncology Pathology, Department of Pathology and Host-Defense, Faculty of Medicine, Kagawa University, Kita-gun 761-0793, Kagawa, Japan;
| | - Masumi Eto
- Department of Molecular Physiology and Biophysics, and Kimmel Cancer Center, Jefferson Medical College, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
- Department of Veterinary Medicine, Faculty of Veterinary Medicine, Okayama University of Science, Imabari 794-8555, Ehime, Japan (Y.T.)
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Scalia P, Williams SJ, Fujita-Yamaguchi Y, Giordano A. Cell cycle control by the insulin-like growth factor signal: at the crossroad between cell growth and mitotic regulation. Cell Cycle 2023; 22:1-37. [PMID: 36005738 PMCID: PMC9769454 DOI: 10.1080/15384101.2022.2108117] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In proliferating cells and tissues a number of checkpoints (G1/S and G2/M) preceding cell division (M-phase) require the signal provided by growth factors present in serum. IGFs (I and II) have been demonstrated to constitute key intrinsic components of the peptidic active fraction of mammalian serum. In vivo genetic ablation studies have shown that the cellular signal triggered by the IGFs through their cellular receptors represents a non-replaceable requirement for cell growth and cell cycle progression. Retroactive and current evaluation of published literature sheds light on the intracellular circuitry activated by these factors providing us with a better picture of the pleiotropic mechanistic actions by which IGFs regulate both cell size and mitogenesis under developmental growth as well as in malignant proliferation. The present work aims to summarize the cumulative knowledge learned from the IGF ligands/receptors and their intracellular signaling transducers towards control of cell size and cell-cycle with particular focus to their actionable circuits in human cancer. Furthermore, we bring novel perspectives on key functional discriminants of the IGF growth-mitogenic pathway allowing re-evaluation on some of its signal components based upon established evidences.
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Affiliation(s)
- Pierluigi Scalia
- ISOPROG-Somatolink EPFP Research Network, Philadelphia, PA, USA, Caltanissetta, Italy,CST, Biology, Sbarro Institute for Cancer Research and Molecular Medicine, Temple University, Philadelphia, PA, United states,CONTACT Pierluigi Scalia ISOPROG-Somatolink EPFP Research Network, Philadelphia, PA9102, USA
| | - Stephen J Williams
- ISOPROG-Somatolink EPFP Research Network, Philadelphia, PA, USA, Caltanissetta, Italy,CST, Biology, Sbarro Institute for Cancer Research and Molecular Medicine, Temple University, Philadelphia, PA, United states
| | - Yoko Fujita-Yamaguchi
- Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, CA, USA
| | - Antonio Giordano
- ISOPROG-Somatolink EPFP Research Network, Philadelphia, PA, USA, Caltanissetta, Italy,School of Medical Biotechnology, University of Siena, Italy
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6
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Garutti M, Bergnach M, Polesel J, Palmero L, Pizzichetta MA, Puglisi F. BRAF and MEK Inhibitors and Their Toxicities: A Meta-Analysis. Cancers (Basel) 2022; 15:cancers15010141. [PMID: 36612138 PMCID: PMC9818023 DOI: 10.3390/cancers15010141] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 12/15/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022] Open
Abstract
PURPOSE This meta-analysis summarizes the incidence of treatment-related adverse events (AE) of BRAFi and MEKi. METHODS A systematic search of Medline/PubMed was conducted to identify suitable articles published in English up to 31 December 2021. The primary outcomes were profiles for all-grade and grade 3 or higher treatment-related AEs, and the analysis of single side effects belonging to both categories. RESULTS The overall incidence of treatment-related all-grade Aes was 99% for Encorafenib (95% CI: 0.97-1.00) and 97% for Trametinib (95% CI: 0.92-0.99; I2 = 66%) and Binimetinib (95% CI: 0.94-0.99; I2 = 0%). In combined therapies, the rate was 98% for both Vemurafenib + Cobimetinib (95% CI: 0.96-0.99; I2 = 77%) and Encorafenib + Binimetinib (95% CI: 0.96-1.00). Grade 3 or higher adverse events were reported in 69% of cases for Binimetinib (95% CI: 0.50-0.84; I2 = 71%), 68% for Encorafenib (95% CI: 0.61-0.74), and 72% for Vemurafenib + Cobimetinib (95% CI: 0.65-0.79; I2 = 84%). The most common grade 1-2 AEs were pyrexia (43%) and fatigue (28%) for Dabrafenib + Trametinib and diarrhea for both Vemurafenib + Cobimetinib (52%) and Encorafenib + Binimetinib (34%). The most common AEs of grade 3 or higher were pyrexia, rash, and hypertension for Dabrafenib + Trametinib (6%), rash and hypertension for Encorafenib + Binimetinib (6%), and increased AST and ALT for Vemurafenib + Cobimetinib (10%). CONCLUSIONS Our study provides comprehensive data on treatment-related adverse events of BRAFi and MEKi combination therapies, showing related toxicity profiles to offer a helpful tool for clinicians in the choice of therapy.
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Affiliation(s)
- Mattia Garutti
- CRO Aviano, National Cancer Institute, IRCCS, 33081 Aviano, Italy
- Correspondence: ; Tel.: +39-04-3465-9092
| | | | - Jerry Polesel
- Unit of Cancer Epidemiology, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, 33081 Aviano, Italy
| | - Lorenza Palmero
- CRO Aviano, National Cancer Institute, IRCCS, 33081 Aviano, Italy
- Department of Medicine, University of Udine, 33100 Udine, Italy
| | - Maria Antonietta Pizzichetta
- CRO Aviano, National Cancer Institute, IRCCS, 33081 Aviano, Italy
- Department of Dermatology, University of Trieste, 34123 Trieste, Italy
| | - Fabio Puglisi
- CRO Aviano, National Cancer Institute, IRCCS, 33081 Aviano, Italy
- Department of Medicine, University of Udine, 33100 Udine, Italy
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7
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Avery TY, Köhler N, Zeiser R, Brummer T, Ruess DA. Onco-immunomodulatory properties of pharmacological interference with RAS-RAF-MEK-ERK pathway hyperactivation. Front Oncol 2022; 12:931774. [PMID: 35965494 PMCID: PMC9363660 DOI: 10.3389/fonc.2022.931774] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/30/2022] [Indexed: 12/25/2022] Open
Abstract
Hyperactivation of the RAS-RAF-MEK-ERK cascade - a mitogen-activated protein kinase pathway – has a well-known association with oncogenesis of leading tumor entities, including non-small cell lung cancer, colorectal carcinoma, pancreatic ductal adenocarcinoma, and malignant melanoma. Increasing evidence shows that genetic alterations leading to RAS-RAF-MEK-ERK pathway hyperactivation mediate contact- and soluble-dependent crosstalk between tumor, tumor microenvironment (TME) and the immune system resulting in immune escape mechanisms and establishment of a tumor-sustaining environment. Consequently, pharmacological interruption of this pathway not only leads to tumor-cell intrinsic disruptive effects but also modification of the TME and anti-tumor immunomodulation. At the same time, the importance of ERK signaling in immune cell physiology and potentiation of anti-tumor immune responses through ERK signaling inhibition within immune cell subsets has received growing appreciation. Specifically, a strong case was made for targeted MEK inhibition due to promising associated immune cell intrinsic modulatory effects. However, the successful transition of therapeutic agents interrupting RAS-RAF-MEK-ERK hyperactivation is still being hampered by significant limitations regarding durable efficacy, therapy resistance and toxicity. We here collate and summarize the multifaceted role of RAS-RAF-MEK-ERK signaling in physiology and oncoimmunology and outline the rationale and concepts for exploitation of immunomodulatory properties of RAS-RAF-MEK-ERK inhibition while accentuating the role of MEK inhibition in combinatorial and intermittent anticancer therapy. Furthermore, we point out the extensive scientific efforts dedicated to overcoming the challenges encountered during the clinical transition of various therapeutic agents in the search for the most effective and safe patient- and tumor-tailored treatment approach.
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Affiliation(s)
- Thomas Yul Avery
- Department of General and Visceral Surgery, Center of Surgery, Medical Center University of Freiburg, Freiburg, Germany
- *Correspondence: Thomas Yul Avery, ; Dietrich Alexander Ruess,
| | - Natalie Köhler
- Department of Medicine I - Medical Center, Medical Center University of Freiburg, Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Robert Zeiser
- Department of Medicine I - Medical Center, Medical Center University of Freiburg, Freiburg, Germany
- German Cancer Consortium Deutsches Konsortium Translationale Krebsforschung (DKTK), partner site Freiburg, German Cancer Research Center Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Tilman Brummer
- German Cancer Consortium Deutsches Konsortium Translationale Krebsforschung (DKTK), partner site Freiburg, German Cancer Research Center Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
- Institute of Molecular Medicine and Cell Research (IMMZ), Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Comprehensive Cancer Center Freiburg (CCCF), Faculty of Medicine, Medical Center University of Freiburg, Freiburg, Germany
| | - Dietrich Alexander Ruess
- Department of General and Visceral Surgery, Center of Surgery, Medical Center University of Freiburg, Freiburg, Germany
- German Cancer Consortium Deutsches Konsortium Translationale Krebsforschung (DKTK), partner site Freiburg, German Cancer Research Center Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
- *Correspondence: Thomas Yul Avery, ; Dietrich Alexander Ruess,
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8
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Alzoughool F, Al-Zghoul MB, Ghanim BY, Gollob M, Idkaidek N, Qinna NA. The Role of Interventional Irisin on Heart Molecular Physiology. Pharmaceuticals (Basel) 2022; 15:ph15070863. [PMID: 35890161 PMCID: PMC9319709 DOI: 10.3390/ph15070863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/04/2022] [Accepted: 07/11/2022] [Indexed: 12/14/2022] Open
Abstract
Irisin, encoded by the FNDC5 (fibronectin type III domain containing 5) gene, is a novel myokine that has been implicated as an essential mediator of exercise benefits. Effects of irisin on heart physiology is still ambiguous. This study aimed to evaluate the impact of exogenous administration of irisin on heart physiology and the pharmacokinetic profile of pump-administered irisin. To do so, Sprague Dawley rats were implanted with an irisin-loaded osmotic pump (5 μg/kg/day) for 42 days, and other animals were administered with single bolus subcutaneous injections of irisin (5 µg/kg). Body weights and blood samples were collected weekly for 42 days for serum irisin quantification and histopathology. Clinical biochemistry analyses were performed. Heart mRNA expression was assessed in 26 selected genes. Chronic interventional exogenous irisin significantly reduced body weight without affecting the heart myocyte size and significantly reduced creatine kinase enzyme level. Blood CBC, serum biochemistry, and heart morphology were normal. Gene expression of FNCD5, Raf1, CPT1, IGF-1, and CALCIN, encoding for heart physiology, increased while PGC1, Nox4, and Mfn1 significantly decreased. Nevertheless, irisin increased the expression of cardioprotective genes and inhibited some genes that harm heart physiology. Administration of irisin promotes myocardial functions and could be translated into clinical settings after preclinical profiling.
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Affiliation(s)
- Foad Alzoughool
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, The Hashemite University, Zarqa 13133, Jordan;
- Faculty of Health Sciences, Higher Colleges of Technology, Fujairah Women’s College, Fujairah P.O. Box. 25026, United Arab Emirates
| | - Mohammad Borhan Al-Zghoul
- Basic Veterinary Sciences, School of Veterinary Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan;
| | - Bayan Y. Ghanim
- University of Petra Pharmaceutical Center (UPPC), University of Petra, Amman 11196, Jordan;
| | - Michael Gollob
- Peter Munk Cardiac Centre, Toronto General Hospital, University of Toronto, Toronto, ON M5G 2N2, Canada;
| | - Nasir Idkaidek
- Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy and Medical Sciences, University of Petra, Amman 11196, Jordan;
| | - Nidal A. Qinna
- University of Petra Pharmaceutical Center (UPPC), University of Petra, Amman 11196, Jordan;
- Department of Pharmacology and Biomedical Sciences, Faculty of Pharmacy and Medical Sciences, University of Petra, Amman 11196, Jordan
- Correspondence:
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9
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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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10
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Venkatanarayan A, Liang J, Yen I, Shanahan F, Haley B, Phu L, Verschueren E, Hinkle TB, Kan D, Segal E, Long JE, Lima T, Liau NPD, Sudhamsu J, Li J, Klijn C, Piskol R, Junttila MR, Shaw AS, Merchant M, Chang MT, Kirkpatrick DS, Malek S. CRAF dimerization with ARAF regulates KRAS-driven tumor growth. Cell Rep 2022; 38:110351. [PMID: 35139374 DOI: 10.1016/j.celrep.2022.110351] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 09/21/2021] [Accepted: 01/19/2022] [Indexed: 02/07/2023] Open
Abstract
KRAS, which is mutated in ∼30% of all cancers, activates the RAF-MEK-ERK signaling cascade. CRAF is required for growth of KRAS mutant lung tumors, but the requirement for CRAF kinase activity is unknown. Here, we show that subsets of KRAS mutant tumors are dependent on CRAF for growth. Kinase-dead but not dimer-defective CRAF rescues growth inhibition, suggesting that dimerization but not kinase activity is required. Quantitative proteomics demonstrates increased levels of CRAF:ARAF dimers in KRAS mutant cells, and depletion of both CRAF and ARAF rescues the CRAF-loss phenotype. Mechanistically, CRAF depletion causes sustained ERK activation and induction of cell-cycle arrest, while treatment with low-dose MEK or ERK inhibitor rescues the CRAF-loss phenotype. Our studies highlight the role of CRAF in regulating MAPK signal intensity to promote tumorigenesis downstream of mutant KRAS and suggest that disrupting CRAF dimerization or degrading CRAF may have therapeutic benefit.
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Affiliation(s)
| | - Jason Liang
- Department of Discovery Oncology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA; Department of Microchemistry, Proteomics and Lipidomics, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Ivana Yen
- Department of Discovery Oncology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Frances Shanahan
- Department of Discovery Oncology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Benjamin Haley
- Department of Molecular Biology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Lilian Phu
- Department of Microchemistry, Proteomics and Lipidomics, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Erik Verschueren
- Department of Microchemistry, Proteomics and Lipidomics, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Trent B Hinkle
- Department of Microchemistry, Proteomics and Lipidomics, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - David Kan
- Department of Translational Oncology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Ehud Segal
- Department of Translational Oncology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Jason E Long
- Department of Translational Oncology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Tony Lima
- Department of Translational Oncology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Nicholas P D Liau
- Department of Structural Biology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Jawahar Sudhamsu
- Department of Structural Biology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Jason Li
- Department of Bioinformatics, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Christiaan Klijn
- Department of Bioinformatics, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Robert Piskol
- Department of Bioinformatics, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Melissa R Junttila
- Department of Translational Oncology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Andrey S Shaw
- Department of Research Biology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Mark Merchant
- Department of Translational Oncology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Matthew T Chang
- Department of Bioinformatics, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Donald S Kirkpatrick
- Department of Microchemistry, Proteomics and Lipidomics, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Shiva Malek
- Department of Discovery Oncology, Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA.
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11
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Abstract
The RASopathies are a group of disorders caused by a germline mutation in one of the genes encoding a component of the RAS/MAPK pathway. These disorders, including neurofibromatosis type 1, Noonan syndrome, cardiofaciocutaneous syndrome, Costello syndrome and Legius syndrome, among others, have overlapping clinical features due to RAS/MAPK dysfunction. Although several of the RASopathies are very rare, collectively, these disorders are relatively common. In this Review, we discuss the pathogenesis of the RASopathy-associated genetic variants and the knowledge gained about RAS/MAPK signaling that resulted from studying RASopathies. We also describe the cell and animal models of the RASopathies and explore emerging RASopathy genes. Preclinical and clinical experiences with targeted agents as therapeutics for RASopathies are also discussed. Finally, we review how the recently developed drugs targeting RAS/MAPK-driven malignancies, such as inhibitors of RAS activation, direct RAS inhibitors and RAS/MAPK pathway inhibitors, might be leveraged for patients with RASopathies.
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Affiliation(s)
- Katie E Hebron
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Edjay Ralph Hernandez
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Marielle E Yohe
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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12
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Ullah R, Yin Q, Snell AH, Wan L. RAF-MEK-ERK pathway in cancer evolution and treatment. Semin Cancer Biol 2021; 85:123-154. [PMID: 33992782 DOI: 10.1016/j.semcancer.2021.05.010] [Citation(s) in RCA: 103] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/03/2021] [Accepted: 05/06/2021] [Indexed: 12/13/2022]
Abstract
The RAF-MEK-ERK signaling cascade is a well-characterized MAPK pathway involved in cell proliferation and survival. The three-layered MAPK signaling cascade is initiated upon RTK and RAS activation. Three RAF isoforms ARAF, BRAF and CRAF, and their downstream MEK1/2 and ERK1/2 kinases constitute a coherently orchestrated signaling module that directs a range of physiological functions. Genetic alterations in this pathway are among the most prevalent in human cancers, which consist of numerous hot-spot mutations such as BRAFV600E. Oncogenic mutations in this pathway often override otherwise tightly regulated checkpoints to open the door for uncontrolled cell growth and neoplasia. The crosstalk between the RAF-MEK-ERK axis and other signaling pathways further extends the proliferative potential of this pathway in human cancers. In this review, we summarize the molecular architecture and physiological functions of the RAF-MEK-ERK pathway with emphasis on its dysregulations in human cancers, as well as the efforts made to target the RAF-MEK-ERK module using small molecule inhibitors.
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Affiliation(s)
- Rahim Ullah
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33612, USA
| | - Qing Yin
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33612, USA
| | - Aidan H Snell
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33612, USA
| | - Lixin Wan
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33612, USA; Department of Cutaneous Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33612, USA.
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13
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Hidden Targets in RAF Signalling Pathways to Block Oncogenic RAS Signalling. Genes (Basel) 2021; 12:genes12040553. [PMID: 33920182 PMCID: PMC8070103 DOI: 10.3390/genes12040553] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 03/30/2021] [Accepted: 04/06/2021] [Indexed: 02/06/2023] Open
Abstract
Oncogenic RAS (Rat sarcoma) mutations drive more than half of human cancers, and RAS inhibition is the holy grail of oncology. Thirty years of relentless efforts and harsh disappointments have taught us about the intricacies of oncogenic RAS signalling that allow us to now get a pharmacological grip on this elusive protein. The inhibition of effector pathways, such as the RAF-MEK-ERK pathway, has largely proven disappointing. Thus far, most of these efforts were aimed at blocking the activation of ERK. Here, we discuss RAF-dependent pathways that are regulated through RAF functions independent of catalytic activity and their potential role as targets to block oncogenic RAS signalling. We focus on the now well documented roles of RAF kinase-independent functions in apoptosis, cell cycle progression and cell migration.
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14
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Drosten M, Barbacid M. Targeting the MAPK Pathway in KRAS-Driven Tumors. Cancer Cell 2020; 37:543-550. [PMID: 32289276 DOI: 10.1016/j.ccell.2020.03.013] [Citation(s) in RCA: 233] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/26/2020] [Accepted: 03/16/2020] [Indexed: 12/19/2022]
Abstract
KRAS mutations occur in a quarter of all of human cancers, yet no selective drug has been approved to treat these tumors. Despite the recent development of drugs that block KRASG12C, the majority of KRAS oncoproteins remain undruggable. Here, we review recent efforts to validate individual components of the mitogen-activated protein kinase (MAPK) pathway as targets to treat KRAS-mutant cancers by comparing genetic information derived from experimental mouse models of KRAS-driven lung and pancreatic tumors with the outcome of selective MAPK inhibitors in clinical trials. We also review the potential of RAF1 as a key target to block KRAS-mutant cancers.
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Affiliation(s)
- Matthias Drosten
- Molecular Oncology Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), Melchor Fernández Almagro 3, 28029 Madrid, Spain.
| | - Mariano Barbacid
- Molecular Oncology Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), Melchor Fernández Almagro 3, 28029 Madrid, Spain.
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15
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Degirmenci U, Wang M, Hu J. Targeting Aberrant RAS/RAF/MEK/ERK Signaling for Cancer Therapy. Cells 2020; 9:E198. [PMID: 31941155 PMCID: PMC7017232 DOI: 10.3390/cells9010198] [Citation(s) in RCA: 281] [Impact Index Per Article: 70.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 12/29/2019] [Accepted: 01/10/2020] [Indexed: 12/13/2022] Open
Abstract
The RAS/RAF/MEK/ERK (MAPK) signaling cascade is essential for cell inter- and intra-cellular communication, which regulates fundamental cell functions such as growth, survival, and differentiation. The MAPK pathway also integrates signals from complex intracellular networks in performing cellular functions. Despite the initial discovery of the core elements of the MAPK pathways nearly four decades ago, additional findings continue to make a thorough understanding of the molecular mechanisms involved in the regulation of this pathway challenging. Considerable effort has been focused on the regulation of RAF, especially after the discovery of drug resistance and paradoxical activation upon inhibitor binding to the kinase. RAF activity is regulated by phosphorylation and conformation-dependent regulation, including auto-inhibition and dimerization. In this review, we summarize the recent major findings in the study of the RAS/RAF/MEK/ERK signaling cascade, particularly with respect to the impact on clinical cancer therapy.
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Affiliation(s)
- Ufuk Degirmenci
- Division of Cellular and Molecular Research, National Cancer Centre Singapore, 11 Hospital Crescent, Singapore 169610, Singapore
| | - Mei Wang
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Jiancheng Hu
- Division of Cellular and Molecular Research, National Cancer Centre Singapore, 11 Hospital Crescent, Singapore 169610, Singapore
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
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16
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Qiu Z, Ye B, Zhao S, Li X, Li L, Mo X, Li W. Non-canonical Raf-1/p70S6K signalling in non-small-cell lung cancer. J Cell Mol Med 2019; 23:7632-7640. [PMID: 31541523 PMCID: PMC6815804 DOI: 10.1111/jcmm.14636] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/04/2019] [Accepted: 07/23/2019] [Indexed: 02/05/2023] Open
Abstract
Lung cancer is the leading cause of cancer-related death globally, with non-small-cell lung cancer (NSCLC) being the predominant subtype. Overall survival remains low for NSCLC patients, and novel targets are needed to improve outcome. Raf-1 is a key component of the Ras/Raf/MEK signalling pathway, but its role and downstream targets in NSCLC are not completely understood. Our previous study indicated a possible correlation between Raf-1 levels and ribosomal protein S6 kinase (p70S6K) function. In this study, we aimed to investigate whether p70S6K is a downstream target of Raf-1 in NSCLC. Raf-1 was silenced in NSCLC cell lines by using small hairpin RNA, and Raf-1 and p70S6K protein levels were measured via Western blot. p70S6K was then overexpressed following Raf-1 knock-down; then, cell proliferation, apoptosis and the cell cycle in NSCLC cell lines were examined. Tumour xenografts with NSCLC cells were then transplanted for in vivo study. Tumours were measured and weighed, and Raf-1 and p70S6K expression, cell proliferation and apoptosis were examined in tumour tissues by Western blot, Ki-67 staining and TUNEL staining, respectively. When Raf-1 was silenced, p70S6K protein levels were markedly decreased in the A549 and H1299 NSCLC cell lines. A significant decrease in NSCLC cell proliferation, a profound increase in apoptosis and cell cycle arrest were observed in vitro following Raf-1 knock-down. Overexpression of p70S6K after Raf-1 depletion effectively reversed these effects. Xenograft studies confirmed these results in vivo. In conclusion, Raf-1 targets p70S6K as its downstream effector to regulate NSCLC tumorigenicity, making Raf-1/p70S6K signalling a promising target for NSCLC treatment.
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Affiliation(s)
- Zhixin Qiu
- Department of Respiratory and Critical Care MedicineWest China HospitalSichuan UniversityChengduChina
| | - Bingwei Ye
- Georgia Cancer CenterAugusta UniversityAugustaGAUSA
| | - Shuang Zhao
- Department of Respiratory and Critical Care MedicineWest China HospitalSichuan UniversityChengduChina
| | - Xin Li
- Georgia Cancer CenterAugusta UniversityAugustaGAUSA,Department of Biochemistry and Molecular BiologyMedical College of GeorgiaAugusta UniversityAugustaGAUSA
| | - Lei Li
- Department of Respiratory and Critical Care MedicineWest China HospitalSichuan UniversityChengduChina
| | - Ximing Mo
- Laboratory of Stem Cell BiologyState Key Laboratory of BiotherapyWest China HospitalSichuan UniversityChengduChina
| | - Weimin Li
- Department of Respiratory and Critical Care MedicineWest China HospitalSichuan UniversityChengduChina
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17
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Jaffré F, Miller CL, Schänzer A, Evans T, Roberts AE, Hahn A, Kontaridis MI. Inducible Pluripotent Stem Cell-Derived Cardiomyocytes Reveal Aberrant Extracellular Regulated Kinase 5 and Mitogen-Activated Protein Kinase Kinase 1/2 Signaling Concomitantly Promote Hypertrophic Cardiomyopathy in RAF1-Associated Noonan Syndrome. Circulation 2019; 140:207-224. [PMID: 31163979 DOI: 10.1161/circulationaha.118.037227] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND More than 90% of individuals with Noonan syndrome (NS) with mutations clustered in the CR2 domain of RAF1 present with severe and often lethal hypertrophic cardiomyopathy (HCM). The signaling pathways by which NS RAF1 mutations promote HCM remain elusive, and so far, there is no known treatment for NS-associated HCM. METHODS We used patient-derived RAF1S257L/+ and CRISPR-Cas9-generated isogenic control inducible pluripotent stem cell (iPSC)-derived cardiomyocytes to model NS RAF1-associated HCM and to further delineate the molecular mechanisms underlying the disease. RESULTS We show that mutant iPSC-derived cardiomyocytes phenocopy the pathology seen in hearts of patients with NS by exhibiting hypertrophy and structural defects. Through pharmacological and genetic targeting, we identify 2 perturbed concomitant pathways that, together, mediate HCM in RAF1 mutant iPSC-derived cardiomyocytes. Hyperactivation of mitogen-activated protein kinase kinase 1/2 (MEK1/2), but not extracellular regulated kinase 1/2, causes myofibrillar disarray, whereas the enlarged cardiomyocyte phenotype is a direct consequence of increased extracellular regulated kinase 5 (ERK5) signaling, a pathway not previously known to be involved in NS. RNA-sequencing reveals genes with abnormal expression in RAF1 mutant iPSC-derived cardiomyocytes and identifies subsets of genes dysregulated by aberrant MEK1/2 or ERK5 pathways that could contribute to the NS-associated HCM. CONCLUSIONS Taken together, the results of our study identify the molecular mechanisms by which NS RAF1 mutations cause HCM and reveal downstream effectors that could serve as therapeutic targets for treatment of NS and perhaps other, more common, congenital HCM disorders.
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Affiliation(s)
- Fabrice Jaffré
- Department of Medicine, Division of Cardiology, Beth Israel Deaconess Medical Center (F.J., M.I.K.).,Harvard Medical School, Boston, MA (F.J., M.I.K.).,Department of Surgery, Weill Cornell Medical College, New York, NY (F.J., T.E.)
| | - Clint L Miller
- Center for Public Health Genomics, Department of Public Health Sciences, Biochemistry and Molecular Genetics, and Biomedical Engineering, University of Virginia, Charlottesville (C.L.M.)
| | - Anne Schänzer
- Institute of Neuropathology (A.S.), University Hospital Giessen, Justus Liebig University Giessen, Germany
| | - Todd Evans
- Department of Surgery, Weill Cornell Medical College, New York, NY (F.J., T.E.)
| | - Amy E Roberts
- Department of Cardiology, Division of Genetics, Boston Children's Hospital, MA (A.E.R.)
| | - Andreas Hahn
- Department of Child Neurology (A.H.), University Hospital Giessen, Justus Liebig University Giessen, Germany
| | - Maria I Kontaridis
- Department of Medicine, Division of Cardiology, Beth Israel Deaconess Medical Center (F.J., M.I.K.).,Department of Biological Chemistry and Molecular Pharmacology (M.I.K.).,Harvard Medical School, Boston, MA (F.J., M.I.K.).,Harvard Stem Cell Institute, Harvard University, Cambridge, MA (M.I.K.).,Masonic Medical Research Institute, Utica, NY (M.I.K.)
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18
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Zaballos MA, Acuña-Ruiz A, Morante M, Crespo P, Santisteban P. Regulators of the RAS-ERK pathway as therapeutic targets in thyroid cancer. Endocr Relat Cancer 2019; 26:R319-R344. [PMID: 30978703 DOI: 10.1530/erc-19-0098] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 04/11/2019] [Indexed: 12/30/2022]
Abstract
Thyroid cancer is mostly an ERK-driven carcinoma, as up to 70% of thyroid carcinomas are caused by mutations that activate the RAS/ERK mitogenic signaling pathway. The incidence of thyroid cancer has been steadily increasing for the last four decades; yet, there is still no effective treatment for advanced thyroid carcinomas. Current research efforts are focused on impairing ERK signaling with small-molecule inhibitors, mainly at the level of BRAF and MEK. However, despite initial promising results in animal models, the clinical success of these inhibitors has been limited by the emergence of tumor resistance and relapse. The RAS/ERK pathway is an extremely complex signaling cascade with multiple points of control, offering many potential therapeutic targets: from the modulatory proteins regulating the activation state of RAS proteins to the scaffolding proteins of the pathway that provide spatial specificity to the signals, and finally, the negative feedbacks and phosphatases responsible for inactivating the pathway. The aim of this review is to give an overview of the biology of RAS/ERK regulators in human cancer highlighting relevant information on thyroid cancer and future areas of research.
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Affiliation(s)
- Miguel A Zaballos
- Instituto de Investigaciones Biomédicas 'Alberto Sols', Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, Madrid, Spain
| | - Adrián Acuña-Ruiz
- Instituto de Investigaciones Biomédicas 'Alberto Sols', Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Morante
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, Madrid, Spain
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Cantabria, Santander, Spain
| | - Piero Crespo
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, Madrid, Spain
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Cantabria, Santander, Spain
| | - Pilar Santisteban
- Instituto de Investigaciones Biomédicas 'Alberto Sols', Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, Madrid, Spain
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19
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A Premature Stop Codon in RAF1 Is the Priority Candidate Causative Mutation of the Inherited Chicken Wingless-2 Developmental Syndrome. Genes (Basel) 2019; 10:genes10050353. [PMID: 31075853 PMCID: PMC6562611 DOI: 10.3390/genes10050353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/23/2019] [Accepted: 04/26/2019] [Indexed: 11/17/2022] Open
Abstract
The chicken wingless-2 (wg-2) mutation is inherited in an autosomal recessive fashion, and the resulting phenotype in mutant (wg-2/wg-2) individuals is a developmental syndrome characterized by absent wings, truncated legs, craniofacial as well as skin and feather defects, and kidney malformations. Mapping and genotyping established that the mutation resides within 227 kilobases (kb) of chromosome 12 in a wg-2 congenic inbred line. A capture array was designed to target and sequence the candidate region along with flanking DNA in 24 birds from the line. Many point mutations and insertions or deletions were identified, and analysis of the linked variants indicated a point mutation predicted to cause a premature stop codon in the RAF1 gene. Expression studies were conducted inclusive of all genes in the candidate region. Interestingly, RAF1 transcription was elevated, yet the protein was absent in the mutants relative to normal individuals. RAF1 encodes a protein integral to the Ras/Raf/MAPK signaling pathway controlling cellular proliferation, and notably, human RASopathies are developmental syndromes caused by germline mutations in genes of this pathway. Our work indicates RAF1 as the priority candidate causative gene for wg-2 and provides a new animal model to study an important signaling pathway implicated in limb development, as well as RASopathies.
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20
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MAP kinase and autophagy pathways cooperate to maintain RAS mutant cancer cell survival. Proc Natl Acad Sci U S A 2019; 116:4508-4517. [PMID: 30709910 DOI: 10.1073/pnas.1817494116] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Oncogenic mutations in the small GTPase KRAS are frequently found in human cancers, and, currently, there are no effective targeted therapies for these tumors. Using a combinatorial siRNA approach, we analyzed a panel of KRAS mutant colorectal and pancreatic cancer cell lines for their dependency on 28 gene nodes that represent canonical RAS effector pathways and selected stress response pathways. We found that RAF node knockdown best differentiated KRAS mutant and KRAS WT cancer cells, suggesting RAF kinases are key oncoeffectors for KRAS addiction. By analyzing all 376 pairwise combination of these gene nodes, we found that cotargeting the RAF, RAC, and autophagy pathways can improve the capture of KRAS dependency better than targeting RAF alone. In particular, codepletion of the oncoeffector kinases BRAF and CRAF, together with the autophagy E1 ligase ATG7, gives the best therapeutic window between KRAS mutant cells and normal, untransformed cells. Distinct patterns of RAS effector dependency were observed across KRAS mutant cell lines, indicative of heterogeneous utilization of effector and stress response pathways in supporting KRAS addiction. Our findings revealed previously unappreciated complexity in the signaling network downstream of the KRAS oncogene and suggest rational target combinations for more effective therapeutic intervention.
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21
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Pfeiffer V, Götz R, Camarero G, Heinsen H, Blum R, Rapp UR. Impaired neuronal maturation of hippocampal neural progenitor cells in mice lacking CRAF. PLoS One 2018; 13:e0192067. [PMID: 29590115 PMCID: PMC5873938 DOI: 10.1371/journal.pone.0192067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 01/16/2018] [Indexed: 11/19/2022] Open
Abstract
RAF kinases are major constituents of the mitogen activated signaling pathway, regulating cell proliferation, differentiation and cell survival of many cell types, including neurons. In mammals, the family of RAF proteins consists of three members, ARAF, BRAF, and CRAF. Ablation of CRAF kinase in inbred mouse strains causes major developmental defects during fetal growth and embryonic or perinatal lethality. Heterozygous germline mutations in CRAF result in Noonan syndrome, which is characterized by neurocognitive impairment that may involve hippocampal physiology. The role of CRAF signaling during hippocampal development and generation of new postnatal hippocampal granule neurons has not been examined and may provide novel insight into the cause of hippocampal dysfunction in Noonan syndrome. In this study, by crossing CRAF-deficiency to CD-1 outbred mice, a CRAF mouse model was established which enabled us to investigate the interplay of neural progenitor proliferation and postmitotic differentiation during adult neurogenesis in the hippocampus. Albeit the general morphology of the hippocampus was unchanged, CRAF-deficient mice displayed smaller granule cell layer (GCL) volume at postnatal day 30 (P30). In CRAF-deficient mice a substantial number of abnormal, chromophilic, fast dividing cells were found in the subgranular zone (SGZ) and hilus of the dentate gyrus (DG), indicating that CRAF signaling contributes to hippocampal neural progenitor proliferation. CRAF-deficient neural progenitor cells showed an increased cell death rate and reduced neuronal maturation. These results indicate that CRAF function affects postmitotic neural cell differentiation and points to a critical role of CRAF-dependent growth factor signaling pathway in the postmitotic development of adult-born neurons.
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Affiliation(s)
- Verena Pfeiffer
- University of Würzburg, Institute of Anatomy and Cell Biology, Koellikerstraße 6, Würzburg, Germany
- University of Würzburg, Institute for Medical Radiation and Cell Research (MSZ), Versbacher Strasse 5, Würzburg, Germany
- * E-mail:
| | - Rudolf Götz
- University of Würzburg, Institute for Medical Radiation and Cell Research (MSZ), Versbacher Strasse 5, Würzburg, Germany
- Institute for Clinical Neurobiology, University Hospital Würzburg, Versbacher Strasse 5, Würzburg, Germany
| | - Guadelupe Camarero
- University of Würzburg, Institute for Medical Radiation and Cell Research (MSZ), Versbacher Strasse 5, Würzburg, Germany
| | - Helmut Heinsen
- University of Würzburg, Department of Psychiatry, Psychosomatics and Psychotherapy, Margarethe-Höppel-Platz 1, Würzburg, Germany
- Universidade de Sao Paulo Faculdade de Medicina, Pathology—LIM 44 Sao Paulo, SP, Brazil
| | - Robert Blum
- Institute for Clinical Neurobiology, University Hospital Würzburg, Versbacher Strasse 5, Würzburg, Germany
| | - Ulf Rüdiger Rapp
- University of Würzburg, Institute for Medical Radiation and Cell Research (MSZ), Versbacher Strasse 5, Würzburg, Germany
- Department of Lung Development and Remodeling, Max Planck Institute for Heart and Lung Research, Parkstr.1, Bad Nauheim, Germany
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22
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Abstract
Therapies for KRas cancers remain a major clinical need. In the current issue of Cancer Cell, Sanclemente and coworkers in Mariano Barbacid's group validate c-Raf as a prime target for these cancers. c-Raf ablation caused regression of advanced KRasG12V/Trp53 tumors, without obvious systemic toxicity and without affecting MAPK signaling.
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Affiliation(s)
- Frank McCormick
- University of California San Francisco, Helen Diller Family Comprehensive Cancer Center, San Francisco, CA, USA.
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23
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Sanclemente M, Francoz S, Esteban-Burgos L, Bousquet-Mur E, Djurec M, Lopez-Casas PP, Hidalgo M, Guerra C, Drosten M, Musteanu M, Barbacid M. c-RAF Ablation Induces Regression of Advanced Kras/Trp53 Mutant Lung Adenocarcinomas by a Mechanism Independent of MAPK Signaling. Cancer Cell 2018; 33:217-228.e4. [PMID: 29395869 DOI: 10.1016/j.ccell.2017.12.014] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 10/24/2017] [Accepted: 12/21/2017] [Indexed: 02/07/2023]
Abstract
A quarter of all solid tumors harbor KRAS oncogenes. Yet, no selective drugs have been approved to treat these malignancies. Genetic interrogation of the MAPK pathway revealed that systemic ablation of MEK or ERK kinases in adult mice prevent tumor development but are unacceptably toxic. Here, we demonstrate that ablation of c-RAF expression in advanced tumors driven by KrasG12V/Trp53 mutations leads to significant tumor regression with no detectable appearance of resistance mechanisms. Tumor regression results from massive apoptosis. Importantly, systemic abrogation of c-RAF expression does not inhibit canonical MAPK signaling, hence, resulting in limited toxicities. These results are of significant relevance for the design of therapeutic strategies to treat K-RAS mutant cancers.
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Affiliation(s)
- Manuel Sanclemente
- Molecular Oncology Program, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid 28029, Spain
| | - Sarah Francoz
- Molecular Oncology Program, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid 28029, Spain
| | - Laura Esteban-Burgos
- Molecular Oncology Program, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid 28029, Spain
| | - Emilie Bousquet-Mur
- Molecular Oncology Program, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid 28029, Spain
| | - Magdolna Djurec
- Molecular Oncology Program, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid 28029, Spain
| | - Pedro P Lopez-Casas
- Clinical Research Program, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid 28029, Spain
| | - Manuel Hidalgo
- Clinical Research Program, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid 28029, Spain
| | - Carmen Guerra
- Molecular Oncology Program, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid 28029, Spain
| | - Matthias Drosten
- Molecular Oncology Program, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid 28029, Spain
| | - Monica Musteanu
- Molecular Oncology Program, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid 28029, Spain.
| | - Mariano Barbacid
- Molecular Oncology Program, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid 28029, Spain.
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Deciphering the RAS/ERK pathway in vivo. Biochem Soc Trans 2017; 45:27-36. [PMID: 28202657 DOI: 10.1042/bst20160135] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 11/03/2016] [Accepted: 11/07/2016] [Indexed: 12/19/2022]
Abstract
The RAS/ERK pathway has been intensely studied for about three decades, not least because of its role in human pathologies. ERK activation is observed in the majority of human cancers; in about one-third of them, it is driven by mutational activation of pathway components. The pathway is arguably one of the best targets for molecule-based pharmacological intervention, and several small-molecule inhibitors are in clinical use. Genetically engineered mouse models have greatly contributed to our understanding of signaling pathways in development, tissue homeostasis, and disease. In the specific case of the RAS/ERK pathway, they have revealed unique biological roles of structurally and functionally similar proteins, new kinase-independent effectors, and unsuspected relationships with other cascades. This short review summarizes the contribution of mouse models to our current understanding of the pathway.
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Feng R, Gong J, Wu L, Wang L, Zhang B, Liang G, Zheng H, Xiao H. MAPK and Hippo signaling pathways crosstalk via the RAF-1/MST-2 interaction in malignant melanoma. Oncol Rep 2017; 38:1199-1205. [PMID: 28677804 DOI: 10.3892/or.2017.5774] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 06/14/2017] [Indexed: 11/05/2022] Open
Abstract
The aim of the present study was to expound on the interactions between the mitogen-activated protein kinase (MAPK) and Hippo pathway members, and to further elucidate the molecular mechanisms of melanoma tumorigenesis. Four melanoma cell lines (C32, HS695T, SK-MEL-28 and A375) were used in the present study. Western blotting was used to assess the expression levels of the MAPK and Hippo pathway effector proteins: rapidly accelerated fibrosarcoma-1 proto-oncogene, serine/threonine kinase (RAF-1); serine/threonine kinase 3 (STK3; also known as MST-2); yes-associated protein (YAP); and tafazzin (TAZ). Immunoprecipitation was used to identify interactions between the effector proteins of the Hippo and MAPK pathways. RAF-1 was knocked down in melanoma cells using siRNA transfection, and cell proliferation, migration and invasion were determined by the MTT, wound-healing and Transwell invasion assays, respectively. Additionally, the cell cycle and apoptosis were analyzed by flow cytometry 48 h after RAF-1 knockdown. We found that the expression levels of the four proteins were variable, and that the HS695T cells expressed the highest levels of RAF-1. Immunoprecipitation studies revealed that RAF-1 bound to MST-2 in melanoma cells. Knockdown of RAF-1 inhibited the expression of YAP and TAZ, but did not affect MST-2 expression. Additionally, RAF-1 knockdown in melanoma cells significantly inhibited cell proliferation, migration and invasion, and induced apoptosis in these cells. Collectively, our results indicate that the RAF-1/MST-2 interaction may be a novel link between the MAPK and Hippo pathways.
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Affiliation(s)
- Ruizheng Feng
- Department of Plastic Surgery, The First Hospital of Shanxi Medical University, Taiyuan, Shanxi 030024, P.R. China
| | - Junsheng Gong
- Department of Plastic Surgery, The First Hospital of Shanxi Medical University, Taiyuan, Shanxi 030024, P.R. China
| | - Lina Wu
- Department of Pathology, The First Hospital of Shanxi Medical University, Taiyuan, Shanxi 030024, P.R. China
| | - Lei Wang
- Department of Gerontology, Shanxi Dayi Hospital, Taiyuan, Shanxi 030000, P.R. China
| | - Baolin Zhang
- Department of Plastic Surgery, The First Hospital of Shanxi Medical University, Taiyuan, Shanxi 030024, P.R. China
| | - Gang Liang
- Department of Pathology, The First Hospital of Shanxi Medical University, Taiyuan, Shanxi 030024, P.R. China
| | - Huixia Zheng
- Department of Pathology, The First Hospital of Shanxi Medical University, Taiyuan, Shanxi 030024, P.R. China
| | - Hong Xiao
- Department of Pathology, The First Hospital of Shanxi Medical University, Taiyuan, Shanxi 030024, P.R. China
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Borovski T, Vellinga TT, Laoukili J, Santo EE, Fatrai S, van Schelven S, Verheem A, Marvin DL, Ubink I, Borel Rinkes IHM, Kranenburg O. Inhibition of RAF1 kinase activity restores apicobasal polarity and impairs tumour growth in human colorectal cancer. Gut 2017; 66:1106-1115. [PMID: 27670374 DOI: 10.1136/gutjnl-2016-311547] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 08/30/2016] [Indexed: 12/08/2022]
Abstract
BACKGROUND AND AIM Colorectal cancer (CRC) remains one of the leading causes of cancer-related death. Novel therapeutics are urgently needed, especially for tumours with activating mutations in KRAS (∼40%). Here we investigated the role of RAF1 in CRC, as a potential, novel target. METHODS Colonosphere cultures were established from human tumour specimens obtained from patients who underwent colon or liver resection for primary or metastatic adenocarcinoma. The role of RAF1 was tested by generating knockdowns (KDs) using three independent shRNA constructs or by using RAF1-kinase inhibitor GW5074. Clone-initiating and tumour-initiating capacities were assessed by single-cell cloning and injecting CRC cells into immune-deficient mice. Expression of tight junction (TJ) proteins, localisation of polarity proteins and activation of MEK-ERK pathway was analysed by western blot, immunohistochemistry and immunofluorescence. RESULTS KD or pharmacological inhibition of RAF1 significantly decreased clone-forming and tumour-forming capacity of all CRC cultures tested, including KRAS-mutants. This was not due to cytotoxicity but, at least in part, to differentiation of tumour cells into goblet-like cells. Inhibition of RAF1-kinase activity restored apicobasal polarity and the formation of TJs in vitro and in vivo, without reducing MEK-ERK phosphorylation. MEK-inhibition failed to restore polarity and TJs. Moreover, RAF1-impaired tumours were characterised by normalised tissue architecture. CONCLUSIONS RAF1 plays a critical role in maintaining the transformed phenotype of CRC cells, including those with mutated KRAS. The effects of RAF1 are kinase-dependent, but MEK-independent. Despite the lack of activating mutations in RAF1, its kinase domain is an attractive therapeutic target for CRC.
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Affiliation(s)
- Tijana Borovski
- Cancer Center, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Thomas T Vellinga
- Cancer Center, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jamila Laoukili
- Cancer Center, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Evan E Santo
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York City, New York, USA
| | - Szabolcs Fatrai
- Department of Hematology, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Andre Verheem
- Cancer Center, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dieuwke L Marvin
- Cancer Center, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Inge Ubink
- Cancer Center, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Onno Kranenburg
- Cancer Center, University Medical Center Utrecht, Utrecht, The Netherlands
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Fairaq A, Shawky NM, Osman I, Pichavaram P, Segar L. AdipoRon, an adiponectin receptor agonist, attenuates PDGF-induced VSMC proliferation through inhibition of mTOR signaling independent of AMPK: Implications toward suppression of neointimal hyperplasia. Pharmacol Res 2017; 119:289-302. [PMID: 28237515 DOI: 10.1016/j.phrs.2017.02.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 01/21/2017] [Accepted: 02/16/2017] [Indexed: 12/12/2022]
Abstract
Hypoadiponectinemia is associated with an increased risk of coronary artery disease. Although adiponectin replenishment mitigates neointimal hyperplasia and atherosclerosis in mouse models, adiponectin therapy has been hampered in a clinical setting due to its large molecular size. Recent studies demonstrate that AdipoRon (a small-molecule adiponectin receptor agonist) improves glycemic control in type 2 diabetic mice and attenuates postischemic cardiac injury in adiponectin-deficient mice, in part, through activation of AMP-activated protein kinase (AMPK). To date, it remains unknown as to whether AdipoRon regulates vascular smooth muscle cell (VSMC) proliferation, which plays a major role in neointima formation. In the present study, oral administration of AdipoRon (50mg/kg) in C57BL/6J mice significantly diminished arterial injury-induced neointima formation by ∼57%. Under in vitro conditions, AdipoRon treatment led to significant inhibition of platelet-derived growth factor (PDGF)-induced VSMC proliferation, DNA synthesis, and cyclin D1 expression. While AdipoRon induced a rapid and sustained activation of AMPK, it also diminished basal and PDGF-induced phosphorylation of mTOR and its downstream targets, including p70S6K/S6 and 4E-BP1. However, siRNA-mediated AMPK downregulation showed persistent inhibition of p70S6K/S6 and 4E-BP1 phosphorylation, indicating AMPK-independent effects for AdipoRon inhibition of mTOR signaling. In addition, AdipoRon treatment resulted in a sustained and transient decrease in PDGF-induced phosphorylation of Akt and ERK, respectively. Furthermore, PDGF receptor-β tyrosine phosphorylation, which controls the phosphorylation state of Akt and ERK, was diminished upon AdipoRon treatment. Together, the present findings suggest that orally-administered AdipoRon has the potential to limit restenosis after angioplasty by targeting mTOR signaling independent of AMPK activation.
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Affiliation(s)
- Arwa Fairaq
- Center for Pharmacy and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA, USA; Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - Noha M Shawky
- Center for Pharmacy and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA, USA; Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - Islam Osman
- Center for Pharmacy and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA, USA; Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - Prahalathan Pichavaram
- Center for Pharmacy and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA, USA; Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - Lakshman Segar
- Center for Pharmacy and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA, USA; Charlie Norwood VA Medical Center, Augusta, GA, USA; Vascular Biology Center, Department of Pharmacology and Toxicology, Augusta University, Augusta, GA, USA; Department of Medicine, Pennsylvania State University College of Medicine, Hershey, PA, USA.
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The lack of Raf-1 kinase feedback regulation enhances antiapoptosis in cancer cells. Oncogene 2016; 36:2014-2022. [PMID: 27841865 DOI: 10.1038/onc.2016.384] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 07/15/2016] [Accepted: 09/04/2016] [Indexed: 12/15/2022]
Abstract
Raf-1 has an important role in cellular antiapoptosis. So far, there is no solid evidence that shows that Raf-1 mutation is associated with cancer development. In the course of further study of Raf-1 signaling, we have reported that Raf-1 hyperphosphorylation inhibits its kinase activity toward its downstream mitogen-activated protein kinase kinase 1/2 (MEK1/2) and proposed a model for negative feedback regulation of Raf-1. Here, we show that there is no hyperphosphorylation in some cancer cells, which results in increased kinase activity and enhances the antiapoptotic ability. Inhibition of either Raf-1 or ALG-2 (apoptosis-linked gene 2) expression results in apoptosis signal-regulating kinase 1/c-Jun N-terminal kinase (ASK1/JNK) signaling activation, and cell sensitivity to chemotherapeutic reagents, indicating that inhibition of ASK1/JNK apoptotic signaling by Raf-1 is mediated by ALG-2. A previous report indicated that extracellular signal-regulated kinase 1/2 (ERK1/2) were responsible for Raf-1 hyperphosphorylation. However, our evidence shows that when ERK1/2 are activated and the Raf-1 gene is not mutated, Raf-1 is not hyperphosphorylated in these cells, indicating that ERK1/2 are not responsible for the Raf-1 hyperphosphorylation in these cancer cell lines. Surprisingly, we also found that Raf-1 is not a necessary kinase for MEK1/2 activation under normal tissue culture conditions, but is required for MEK1/2 activation under apoptosis-inducing conditions. Our research demonstrates that although Raf-1 gene is not mutated, an abnormality of Raf-1 kinase feedback regulation enhances its antiapoptotic function, and Raf-1 can still be a pharmaceutical target to increase chemotherapy or radiotherapy sensitivity in these cancer cells.
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Chodari L, Mohammadi M, Mohaddes G, Alipour MR, Ghorbanzade V, Dariushnejad H, Mohammadi S. Testosterone and Voluntary Exercise, Alone or Together Increase Cardiac Activation of AKT and ERK1/2 in Diabetic Rats. Arq Bras Cardiol 2016; 107:532-541. [PMID: 28558078 PMCID: PMC5210457 DOI: 10.5935/abc.20160174] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 08/04/2016] [Indexed: 01/03/2023] Open
Abstract
Background Impaired angiogenesis in cardiac tissue is a major complication of diabetes.
Protein kinase B (AKT) and extracellular signal regulated kinase (ERK)
signaling pathways play important role during capillary-like network
formation in angiogenesis process. Objectives To determine the effects of testosterone and voluntary exercise on levels of
vascularity, phosphorylated Akt (P- AKT) and phosphorylated ERK (P-ERK) in
heart tissue of diabetic and castrated diabetic rats. Methods Type I diabetes was induced by i.p injection of 50 mg/kg of streptozotocin in
animals. After 42 days of treatment with testosterone (2mg/kg/day) or
voluntary exercise alone or in combination, heart tissue samples were
collected and used for histological evaluation and determination of P-AKT
and P-ERK levels by ELISA method. Results Our results showed that either testosterone or exercise increased
capillarity, P-AKT, and P-ERK levels in the heart of diabetic rats.
Treatment of diabetic rats with testosterone and exercise had a synergistic
effect on capillarity, P-AKT, and P-ERK levels in heart. Furthermore, in the
castrated diabetes group, capillarity, P-AKT, and P-ERK levels significantly
decreased in the heart, whereas either testosterone treatment or exercise
training reversed these effects. Also, simultaneous treatment of castrated
diabetic rats with testosterone and exercise had an additive effect on P-AKT
and P-ERK levels. Conclusion Our findings suggest that testosterone and exercise alone or together can
increase angiogenesis in the heart of diabetic and castrated diabetic rats.
The proangiogenesis effects of testosterone and exercise are associated with
the enhanced activation of AKT and ERK1/2 in heart tissue.
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Affiliation(s)
- Leila Chodari
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mustafa Mohammadi
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Gisou Mohaddes
- Neuroscience Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Vajiheh Ghorbanzade
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hassan Dariushnejad
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Shima Mohammadi
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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Abstract
The MST1 and MST2 protein kinases comprise the GCK-II subfamily of protein kinases. In addition to their amino-terminal kinase catalytic domain, related to that of the Saccharomyces cerevisiae protein kinase Ste20, their most characteristic feature is the presence near the carboxy terminus of a unique helical structure called a SARAH domain; this segment allows MST1/MST2 to homodimerize and to heterodimerize with the other polypeptides that contain SARAH domains, the noncatalytic polypeptides RASSF1-6 and Sav1/WW45. Early studies emphasized the potent ability of MST1/MST2 to induce apoptosis upon being overexpressed, as well as the conversion of the endogenous MST1/MST2 polypeptides to constitutively active, caspase-cleaved catalytic fragments during apoptosis initiated by any stimulus. Later, the cleaved, constitutively active form of MST1 was identified in nonapoptotic, quiescent adult hepatocytes as well as in cells undergoing terminal differentiation, where its presence is necessary to maintain those cellular states. The physiologic regulation of full length MST1/MST2 is controlled by the availability of its noncatalytic SARAH domain partners. Interaction with Sav1/WW45 recruits MST1/MST2 into a tumor suppressor pathway, wherein it phosphorylates and activates the Sav1-bound protein kinases Lats1/Lats2, potent inhibitors of the Yap1 and TAZ oncogenic transcriptional regulators. A constitutive interaction with the Rap1-GTP binding protein RASSF5B (Nore1B/RAPL) in T cells recruits MST1 (especially) and MST2 as an effector of Rap1's control of T cell adhesion and migration, a program crucial to immune surveillance and response; loss of function mutation in human MST1 results in profound immunodeficiency. MST1 and MST2 are also regulated by other protein kinases, positively by TAO1 and negatively by Par1, SIK2/3, Akt, and cRaf1. The growing list of candidate MST1/MST2 substrates suggests that the full range of MST1/MST2's physiologic programs and contributions to pathophysiology remains to be elucidated.
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Affiliation(s)
- Jacob A. Galan
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
- Diabetes Unit and Medical Services, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
- Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Joseph Avruch
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
- Diabetes Unit and Medical Services, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
- Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, United States
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Hernandez MA, Patel B, Hey F, Giblett S, Davis H, Pritchard C. Regulation of BRAF protein stability by a negative feedback loop involving the MEK-ERK pathway but not the FBXW7 tumour suppressor. Cell Signal 2016; 28:561-71. [PMID: 26898828 PMCID: PMC6399479 DOI: 10.1016/j.cellsig.2016.02.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 02/08/2016] [Accepted: 02/15/2016] [Indexed: 01/06/2023]
Abstract
The V600EBRAF oncogenic mutation is detected in a wide range of human cancers and induces hyperactivation of the downstream MEK–ERK signalling cascade. Although output of the BRAF–MEK–ERK pathway is regulated by feed-forward RAF activity, feedback control also plays an important role. One such feedback pathway has been identified in Caenorhabditis elegans and involves ERK-mediated phosphorylation of BRAF within a CDC4 phosphodegron (CPD), targeting BRAF for degradation via CDC4 (also known as FBXW7), a component of the SKP1/CUL1/F-box (SCF) E3 ubiquitin ligase complex. Here we investigate this pathway in mammalian cells. Short-term expression of autochthonous V600EBRAF in mouse embryonic fibroblasts (MEFs) leads to down-regulation of BRAF protein levels in a proteasome-dependent manner and V600EBRAF has a reduced half-life compared to WTBRAF in HEK293T cells. These effects were reversed by treatment with the MEK inhibitor PD184352. We have identified the equivalent CPD at residues 400–405 in human BRAF and have found that mutation of ERK phosphorylation sites at residues T401 and S405 in V600EBRAF increases the half-life of the protein. While BRAF and FBXW7 co-immunoprecipitated, the overexpression of FBXW7 did not influence the half-life of either WTBRAF or V600EBRAF. Furthermore, disruption of the substrate-binding site of mouse FBXW7 using the R482Q mutation did not affect the interaction with BRAF and the expression levels of WTBRAF and V600EBRAF were not altered in MEFs derived from mice with the homozygous knockin R482QFBXW7 mutation. Overall these data confirm the existence of a negative feedback pathway by which BRAF protein stability is regulated by ERK. However, unlike the situation in C. elegans, FBXW7 does not play a unique role in mediating subsequent BRAF degradation. Expression of oncogenic V600EBRAF down-regulates BRAF expression at the protein level. V600EBRAF has a shorter half-life than WTBRAF. BRAF protein stability is subjected to feedback control by the MEK/ERK pathway. This feedback pathway is associated with the oncogene-induced senescence phenotype. ERK phosphorylation sites at T401 and S405 within a conserved CDC4 (FBXW7) phosphodegron of BRAF are involved in the feedback control pathway. The FBXW7 substrate recognition component of the SKP1/CUL1/F-box (SCF) complex binds to BRAF but is not uniquely involved in the regulation of its protein turnover.
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Affiliation(s)
- Maria Aguilar Hernandez
- Department of Molecular Cell Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Bipin Patel
- Department of Molecular Cell Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Fiona Hey
- Department of Molecular Cell Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Susan Giblett
- Department of Molecular Cell Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Hayley Davis
- Gastrointestinal Stem Cell Biology Laboratory, Wellcome Trust Centre for Human Genetics, Oxford University, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Catrin Pritchard
- Department of Molecular Cell Biology, University of Leicester, University Road, Leicester LE1 7RH, UK; Department of Cancer Studies, University of Leicester, University Road, Leicester LE1 7RH, UK.
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Abstract
RAF family kinases were among the first oncoproteins to be described more than 30 years ago. They primarily act as signalling relays downstream of RAS, and their close ties to cancer have fuelled a large number of studies. However, we still lack a systems-level understanding of their regulation and mode of action. The recent discovery that the catalytic activity of RAF depends on an allosteric mechanism driven by kinase domain dimerization is providing a vital new piece of information towards a comprehensive model of RAF function. The fact that current RAF inhibitors unexpectedly induce ERK signalling by stimulating RAF dimerization also calls for a deeper structural characterization of this family of kinases.
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Tsai YT, Chuang MJ, Tang SH, Wu ST, Chen YC, Sun GH, Hsiao PW, Huang SM, Lee HJ, Yu CP, Ho JY, Lin HK, Chen MR, Lin CC, Chang SY, Lin VC, Yu DS, Cha TL. Novel Cancer Therapeutics with Allosteric Modulation of the Mitochondrial C-Raf-DAPK Complex by Raf Inhibitor Combination Therapy. Cancer Res 2015; 75:3568-82. [PMID: 26100670 DOI: 10.1158/0008-5472.can-14-3264] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 05/04/2015] [Indexed: 11/16/2022]
Abstract
Mitochondria are the powerhouses of cells. Mitochondrial C-Raf is a potential cancer therapeutic target, as it regulates mitochondrial function and is localized to the mitochondria by its N-terminal domain. However, Raf inhibitor monotherapy can induce S338 phosphorylation of C-Raf (pC-Raf(S338)) and impede therapy. This study identified the interaction of C-Raf with S308 phosphorylated DAPK (pDAPK(S308)), which together became colocalized in the mitochondria to facilitate mitochondrial remodeling. Combined use of the Raf inhibitors sorafenib and GW5074 had synergistic anticancer effects in vitro and in vivo, but targeted mitochondrial function, rather than the canonical Raf signaling pathway. C-Raf depletion in knockout MEF(C-Raf-/-) or siRNA knockdown ACHN renal cancer cells abrogated the cytotoxicity of combination therapy. Crystal structure simulation showed that GW5074 bound to C-Raf and induced a C-Raf conformational change that enhanced sorafenib-binding affinity. In the presence of pDAPK(S308), this drug-target interaction compromised the mitochondrial targeting effect of the N-terminal domain of C-Raf, which induced two-hit damages to cancer cells. First, combination therapy facilitated pC-Raf(S338) and pDAPK(S308) translocation from mitochondria to cytoplasm, leading to mitochondrial dysfunction and reactive oxygen species (ROS) generation. Second, ROS facilitated PP2A-mediated dephosphorylation of pDAPK(S308) to DAPK. PP2A then dissociated from the C-Raf-DAPK complex and induced profound cancer cell death. Increased pDAPK(S308) modification was also observed in renal cancer tissues, which correlated with poor disease-free survival and poor overall survival in renal cancer patients. Besides mediating the anticancer effect, pDAPK(S308) may serve as a predictive biomarker for Raf inhibitors combination therapy, suggesting an ideal preclinical model that is worthy of clinical translation.
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Affiliation(s)
- Yi-Ta Tsai
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China. Division of Urology, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Mei-Jen Chuang
- Division of Urology, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Shou-Hung Tang
- Division of Urology, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Sheng-Tang Wu
- Division of Urology, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Yu-Chi Chen
- Division of Urology, Department of Surgery, E-Da Hospital, Kaohsiung, Taiwan, Republic of China
| | - Guang-Huan Sun
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China. Division of Urology, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China. Graduate Institutes of Life Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Pei-Wen Hsiao
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Shih-Ming Huang
- Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Hwei-Jen Lee
- Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Cheng-Ping Yu
- Graduate Institutes of Life Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China. Graduate Institute of Pathology and Parasitology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Jar-Yi Ho
- Graduate Institutes of Life Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China. Graduate Institute of Pathology and Parasitology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Hui-Kuan Lin
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas. The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas
| | - Ming-Rong Chen
- Division of Urology, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China. Graduate Institutes of Life Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Chung-Chih Lin
- Division of Urology, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Sun-Yran Chang
- Division of Urology, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China. Taipei City Hospital, Taipei, Taiwan, Republic of China
| | - Victor C Lin
- Division of Urology, Department of Surgery, E-Da Hospital, Kaohsiung, Taiwan, Republic of China
| | - Dah-Shyong Yu
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China. Division of Urology, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China. Graduate Institutes of Life Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Tai-Lung Cha
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China. Division of Urology, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China. Graduate Institutes of Life Sciences, National Defense Medical Center, Taipei, Taiwan, Republic of China. Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, Republic of China.
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de Iriarte Rodríguez R, Magariños M, Pfeiffer V, Rapp UR, Varela-Nieto I. C-Raf deficiency leads to hearing loss and increased noise susceptibility. Cell Mol Life Sci 2015; 72:3983-98. [PMID: 25975225 PMCID: PMC4575698 DOI: 10.1007/s00018-015-1919-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 04/21/2015] [Accepted: 04/27/2015] [Indexed: 12/20/2022]
Abstract
The family of RAF kinases transduces extracellular information to the nucleus, and their activation is crucial for cellular regulation on many levels, ranging from embryonic development to carcinogenesis. B-RAF and C-RAF modulate neurogenesis and neuritogenesis during chicken inner ear development. C-RAF deficiency in humans is associated with deafness in the rare genetic insulin-like growth factor 1 (IGF-1), Noonan and Leopard syndromes. In this study, we show that RAF kinases are expressed in the developing inner ear and in adult mouse cochlea. A homozygous C-Raf deletion in mice caused profound deafness with no evident cellular aberrations except for a remarkable reduction of the K+ channel Kir4.1 expression, a trait that suffices as a cause of deafness. To explore the role of C-Raf in cellular protection and repair, heterozygous C-Raf+/− mice were exposed to noise. A reduced C-RAF level negatively affected hearing preservation in response to noise through mechanisms involving the activation of JNK and an exacerbated apoptotic response. Taken together, these results strongly support a role for C-RAF in hearing protection.
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Affiliation(s)
- Rocío de Iriarte Rodríguez
- Instituto de Investigaciones Biomédicas "Alberto Sols", CSIC-UAM, Arturo Duperier 4, 28029, Madrid, Spain.,Centre for Biomedical Network Research (CIBERER), Institute of Health Carlos III (ISCIII), Madrid, Spain
| | - Marta Magariños
- Instituto de Investigaciones Biomédicas "Alberto Sols", CSIC-UAM, Arturo Duperier 4, 28029, Madrid, Spain. .,Centre for Biomedical Network Research (CIBERER), Institute of Health Carlos III (ISCIII), Madrid, Spain. .,Departamento de Biología, Universidad Autónoma de Madrid, Darwin 2, 28049, Madrid, Spain.
| | - Verena Pfeiffer
- Institute for Medical Radiation and Cell Research (MSZ), University of Würzburg, Versbacher Strasse 5, 97078, Würzburg, Germany.,Institute for Anatomy and Cell Biology, University of Würzburg, Koellikerstraße 6, 97070, Würzburg, Germany
| | - Ulf R Rapp
- Institute for Medical Radiation and Cell Research (MSZ), University of Würzburg, Versbacher Strasse 5, 97078, Würzburg, Germany.,Molecular Mechanisms of Lung Cancer, Max Planck Institute for Heart and Lung Research, Parkstr. 1, 61231, Bad Nauheim, Germany
| | - Isabel Varela-Nieto
- Instituto de Investigaciones Biomédicas "Alberto Sols", CSIC-UAM, Arturo Duperier 4, 28029, Madrid, Spain.,Centre for Biomedical Network Research (CIBERER), Institute of Health Carlos III (ISCIII), Madrid, Spain.,Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain
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Gonsalvez D, Ferner AH, Peckham H, Murray SS, Xiao J. The roles of extracellular related-kinases 1 and 2 signaling in CNS myelination. Neuropharmacology 2015; 110:586-593. [PMID: 25959068 DOI: 10.1016/j.neuropharm.2015.04.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 04/16/2015] [Accepted: 04/27/2015] [Indexed: 01/09/2023]
Abstract
Substantial progress has been made in identifying the intracellular signaling pathways that regulate central nervous system myelination. Recently, the mitogen activated protein kinase pathway, in particular the extracellular signal-related kinase 1 (Erk1) and Erk2, have been identified as critically important in mediating the effects of several growth factors that regulate oligodendroglial development and myelination. Here we will review the recent studies that identify the key role that Erk1/2 signaling plays in regulating oligodendroglial development, myelination and remyelination, discuss the potential mechanisms that Erk1/2 may utilize to influence myelination, and highlight some questions for further research. This article is part of the Special Issue entitled 'Oligodendrocytes in Health and Disease'.
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Affiliation(s)
- David Gonsalvez
- Department of Anatomy and Neuroscience, The University of Melbourne, Victoria 3010, Australia
| | - Anita H Ferner
- Department of Anatomy and Neuroscience, The University of Melbourne, Victoria 3010, Australia
| | - Haley Peckham
- Department of Anatomy and Neuroscience, The University of Melbourne, Victoria 3010, Australia
| | - Simon S Murray
- Department of Anatomy and Neuroscience, The University of Melbourne, Victoria 3010, Australia; The Florey Institute of Neuroscience and Mental Health Research, The University of Melbourne, Victoria 3010, Australia
| | - Junhua Xiao
- Department of Anatomy and Neuroscience, The University of Melbourne, Victoria 3010, Australia; The Florey Institute of Neuroscience and Mental Health Research, The University of Melbourne, Victoria 3010, Australia.
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Magnetic resonance-imaging of the effect of targeted antiangiogenic gene delivery in a melanoma tumour model. Eur Radiol 2014; 25:1107-18. [PMID: 25432291 DOI: 10.1007/s00330-014-3492-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Revised: 10/24/2014] [Accepted: 11/10/2014] [Indexed: 10/24/2022]
Abstract
OBJECTIVES We investigated the effect of targeted gene therapy to melanoma tumours (M21) by MR-imaging. METHODS M21 and M21-L tumours were grown to a size of 850 mm(3). M21 and M21-L tumours were intravenously treated with an αvβ3-integrin-ligand-coupled nanoparticle (RGDNP)/RAF(-) complex five times every 72 hours. MRI was performed at set time intervals 24h and 72h after the i.v. injection of the complex. The MRI protocol was T1-wt-SE±CM, T2-wt-FSE, DCE-MRI, Diffusion-wt-STEAM-sequence, T2-time obtained on a 1.5-T-GE-MRI device. RESULTS The size of the treated M21 tumours kept nearly constant during the treatment phase (847.8±31.4 mm(3) versus 904.8±44.4 mm(3)). The SNR value (T2-weighted images) of the tumours was 36.7±0.6 and dropped down to 30.6±1.9 (p=0.004). At the beginning the SNR value (T1-weighted images) of the tumours after contrast medium application was 42.3±1.9 and dropped down to 28.5±3.0 (p<0.001). In the treatment group the diffusion coefficient increased significantly under therapy (0.54±0.01x10(-3) mm(2)/s versus 0.67±0.04x10(-3) mm(2)/s). The DCE-MRI showed a reduction of the slope and of the Akep of 67.8±4.3 % respectively 64.8±3.3 % compared to baseline. CONCLUSIONS Targeted gene delivery therapy induces significant changes in MR-imaging. MRI showed a significant reduction of contrast medium uptake parameters and increase of the diffusion coefficient of the tumours. KEY POINT • Treatment with targeted gene-delivery therapy can be monitored by MR imaging • DCE and diffusion-weighted imaging are appropriate methods for monitoring this therapy • Functional changes are significant prior to any morphological changes.
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Abstract
Transformation of a normal cell to a cancer cell is caused by mutations in genes that regulate proliferation, apoptosis, and invasion. Small GTPases such as Ras, Rho, Rac and Cdc42 orchestrate many of the signals that are required for malignant transformation. The p21-activated kinases (PAKs) are effectors of Rac and Cdc42. PAKs are a family of serine/threonine protein kinases comprised of six isoforms (PAK1–6), and they play important roles in cytoskeletal dynamics, cell survival and proliferation. They act as key signal transducers in several cancer signaling pathways, including Ras, Raf, NFκB, Akt, Bad and p53. Although PAKs are not mutated in cancers, they are overexpressed, hyperactivated or amplified in several human tumors and their role in cell transformation make them attractive therapeutic targets. This review discusses the evidence that PAK is important for cell transformation and some key signaling pathways it regulates. This review primarily discusses Group I PAKs (PAK1, PAK2 and PAK3) as Group II PAKs (PAK4, PAK5 and PAK6) are discussed elsewhere in this issue (by Minden).
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Affiliation(s)
- Diana Zi Ye
- Department of Pharmacology; Perelman School of Medicine; University of Pennsylvania; Philadelphia, PA USA
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Fazio N, Abdel-Rahman O, Spada F, Galdy S, De Dosso S, Capdevila J, Scarpa A. RAF signaling in neuroendocrine neoplasms: from bench to bedside. Cancer Treat Rev 2014; 40:974-9. [PMID: 24998490 DOI: 10.1016/j.ctrv.2014.06.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Revised: 06/16/2014] [Accepted: 06/17/2014] [Indexed: 12/23/2022]
Abstract
Neuroendocrine neoplasms are a low-incidence and heterogeneous group of malignancies. In the advanced stage, several therapeutic options can be discussed, including molecular-targeted agents, but biological predicting factors are lacking. A number of molecular targets have been studied over the last decade leading to several phase II studies; however, very few agents progressed to phase III clinical trials. The RAF family of proteins belongs to the mitogen-activated protein kinase (MAPK) pathway, that has a role in several types of cancers, particularly related to BRAF mutations. Indeed BRAF inhibitors have been reported as being effective, mainly in melanoma. However, in neuroendocrine neoplasms BRAF mutations are extremely rare and RAF-1 activation has been reported to inhibit tumor growth in a pre-clinical setting. Therefore, in this field, RAF-1 activators rather than BRAF inhibitors should be clinically investigated. This article reviews the basic science as well as clinical data of RAF signaling in advanced neuroendocrine neoplasms with special emphasis on the potential role of both RAF activators and inhibitors.
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Affiliation(s)
- Nicola Fazio
- Unit of Gastrointestinal Medical Oncology and Neuroendocrine Tumors, European Institute of Oncology, Milan, Italy.
| | - Omar Abdel-Rahman
- Clinical Oncology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Francesca Spada
- Unit of Gastrointestinal Medical Oncology and Neuroendocrine Tumors, European Institute of Oncology, Milan, Italy
| | - Salvatore Galdy
- Unit of Gastrointestinal Medical Oncology and Neuroendocrine Tumors, European Institute of Oncology, Milan, Italy
| | - Sara De Dosso
- Oncology Institute of Southern Switzerland, Bellinzona, Switzerland
| | - Jaume Capdevila
- Medical Oncology Department, Vall d'Hebron University Hospital, Barcelona, Spain
| | - Aldo Scarpa
- Department of Pathology and Diagnostics, ARC-NET Research Center, University of Verona, Italy
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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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41
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Allosteric activation of functionally asymmetric RAF kinase dimers. Cell 2013; 154:1036-1046. [PMID: 23993095 DOI: 10.1016/j.cell.2013.07.046] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 03/18/2013] [Accepted: 07/31/2013] [Indexed: 01/07/2023]
Abstract
Although RAF kinases are critical for controlling cell growth, their mechanism of activation is incompletely understood. Recently, dimerization was shown to be important for activation. Here we show that the dimer is functionally asymmetric with one kinase functioning as an activator to stimulate activity of the partner, receiver kinase. The activator kinase did not require kinase activity but did require N-terminal phosphorylation that functioned allosterically to induce cis-autophosphorylation of the receiver kinase. Based on modeling of the hydrophobic spine assembly, we also engineered a constitutively active mutant that was independent of Ras, dimerization, and activation-loop phosphorylation. As N-terminal phosphorylation of BRAF is constitutive, BRAF initially functions to activate CRAF. N-terminal phosphorylation of CRAF was dependent on MEK, suggesting a feedback mechanism and explaining a key difference between BRAF and CRAF. Our work illuminates distinct steps in RAF activation that function to assemble the active conformation of the RAF kinase.
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Koziel K, Smigelskaite J, Drasche A, Enthammer M, Ashraf MI, Khalid S, Troppmair J. RAF and antioxidants prevent cell death induction after growth factor abrogation through regulation of Bcl-2 proteins. Exp Cell Res 2013; 319:2728-38. [PMID: 23933517 PMCID: PMC3809515 DOI: 10.1016/j.yexcr.2013.07.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 07/19/2013] [Accepted: 07/29/2013] [Indexed: 01/31/2023]
Abstract
We have shown previously that mitochondrial ROS production is essential to turn growth factor (GF) removal into cell death. Activated RAF, AKT, Bcl-2 and antioxidants protected equally well against ROS accumulation and subsequent death. Here we investigated whether protection by survival signaling and antioxidants utilizes shared or distinct targets. Using serum deprivation from NIH 3T3 fibroblasts and IL-3 withdrawal from promyeloid 32D cells, we showed that pro-survival signaling by activated RAF but not AKT prevented the decline in Mcl-1 following GF abrogation. GF starvation increased levels of Bim in both model systems, which was prevented by RAF in 32D cells but not in NIH 3T3 fibroblasts. RAF and AKT suppressed activation and mitochondrial translocation of BAX. Also, antioxidant treatment efficiently prevented BAX activation and death of 32D cells but showed little effect on its mitochondrial translocation. No significant impact of antioxidant treatment on Bim or Mcl-1 expression was observed. ROS produced during GF abrogation also did not alter the activity of intracellular signaling pathways, which have been implicated previously in cell killing by pro-oxidants. Together these data suggest Bcl-2 family proteins as convergence point for RAF and ROS in life and death decisions.
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Affiliation(s)
- Katarzyna Koziel
- Daniel Swarovski Research Laboratory, Department of Visceral-, Transplant- and Thoracic Surgery, Innsbruck Medical University, Austria
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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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Zeng L, Ehrenreiter K, Menon J, Menard R, Kern F, Nakazawa Y, Bevilacqua E, Imamoto A, Baccarini M, Rosner MR. RKIP regulates MAP kinase signaling in cells with defective B-Raf activity. Cell Signal 2013; 25:1156-65. [PMID: 23416466 DOI: 10.1016/j.cellsig.2013.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 02/08/2013] [Indexed: 01/05/2023]
Abstract
MAP kinase (MAPK) signaling results from activation of Raf kinases in response to external or internal stimuli. Here, we demonstrate that Raf kinase inhibitory protein (RKIP) regulates the activation of MAPK when B-Raf signaling is defective. We used multiple models including mouse embryonic fibroblasts (MEFs) and primary keratinocytes from RKIP- or Raf-deficient mice as well as allografts in mice to investigate the mechanism. Loss of B-Raf protein or activity significantly reduces MAPK activation in these cells. We show that RKIP depletion can rescue the compromised ERK activation and promote proliferation, and this rescue occurs through a Raf-1 dependent mechanism. These results provide formal evidence that RKIP is a bona fide regulator of Raf-1. We propose a new model in which RKIP plays a key role in regulating the ability of cells to signal through Raf-1 to ERK in B-Raf compromised cells.
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Affiliation(s)
- Lingchun Zeng
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL 60637, USA
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45
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Acikyol B, Graham RM, Trinder D, House MJ, Olynyk JK, Scott RJ, Milward EA, Johnstone DM. Brain transcriptome perturbations in the transferrin receptor 2 mutant mouse support the case for brain changes in iron loading disorders, including effects relating to long-term depression and long-term potentiation. Neuroscience 2013; 235:119-28. [PMID: 23333676 DOI: 10.1016/j.neuroscience.2013.01.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 12/14/2012] [Accepted: 01/02/2013] [Indexed: 11/16/2022]
Abstract
Iron abnormalities within the brain are associated with several rare but severe neurodegenerative conditions. There is growing evidence that more common systemic iron loading disorders such as hemochromatosis can also have important effects on the brain. To identify features that are common across different forms of hemochromatosis, we used microarray and real-time reverse transcription polymerase chain reaction (RT-PCR) to assess brain transcriptome profiles of transferrin receptor 2 mutant mice (Tfr2(mut)), a model of a rare type of hereditary hemochromatosis, relative to wildtype control mice. The results were compared with our previous findings in dietary iron-supplemented wildtype mice and Hfe(-/-) mice, a model of a common type of hereditary hemochromatosis. For transcripts showing significant changes relative to controls across all three models, there was perfect (100%) directional concordance (i.e. transcripts were increased in all models or decreased in all models). Comparison of the two models of hereditary hemochromatosis, which showed more pronounced changes than the dietary iron-supplemented mice, revealed numerous common molecular effects. Pathway analyses highlighted changes for genes relating to long-term depression (6.8-fold enrichment, p=5.4×10(-7)) and, to a lesser extent, long-term potentiation (3.7-fold enrichment, p=0.01), with generalized reductions in transcription of key genes from these pathways, which are involved in modulating synaptic strength and efficacy and are essential for memory and learning. The agreement across the models suggests the findings are robust and strengthens previous evidence that iron loading disorders affect the brain. Perturbations of brain phenomena such as long-term depression and long-term potentiation might partly explain neurologic symptoms reported for some hemochromatosis patients.
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Affiliation(s)
- B Acikyol
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia
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Miller JP, Yates BE, Al-Ramahi I, Berman AE, Sanhueza M, Kim E, de Haro M, DeGiacomo F, Torcassi C, Holcomb J, Gafni J, Mooney SD, Botas J, Ellerby LM, Hughes RE. A genome-scale RNA-interference screen identifies RRAS signaling as a pathologic feature of Huntington's disease. PLoS Genet 2012; 8:e1003042. [PMID: 23209424 PMCID: PMC3510027 DOI: 10.1371/journal.pgen.1003042] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 08/29/2012] [Indexed: 11/19/2022] Open
Abstract
A genome-scale RNAi screen was performed in a mammalian cell-based assay to identify modifiers of mutant huntingtin toxicity. Ontology analysis of suppressor data identified processes previously implicated in Huntington's disease, including proteolysis, glutamate excitotoxicity, and mitochondrial dysfunction. In addition to established mechanisms, the screen identified multiple components of the RRAS signaling pathway as loss-of-function suppressors of mutant huntingtin toxicity in human and mouse cell models. Loss-of-function in orthologous RRAS pathway members also suppressed motor dysfunction in a Drosophila model of Huntington's disease. Abnormal activation of RRAS and a down-stream effector, RAF1, was observed in cellular models and a mouse model of Huntington's disease. We also observe co-localization of RRAS and mutant huntingtin in cells and in mouse striatum, suggesting that activation of R-Ras may occur through protein interaction. These data indicate that mutant huntingtin exerts a pathogenic effect on this pathway that can be corrected at multiple intervention points including RRAS, FNTA/B, PIN1, and PLK1. Consistent with these results, chemical inhibition of farnesyltransferase can also suppress mutant huntingtin toxicity. These data suggest that pharmacological inhibition of RRAS signaling may confer therapeutic benefit in Huntington's disease.
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Affiliation(s)
- John P. Miller
- The Buck Institute for Research on Aging, Novato, California, United States of America
| | - Bridget E. Yates
- The Buck Institute for Research on Aging, Novato, California, United States of America
| | - Ismael Al-Ramahi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ari E. Berman
- The Buck Institute for Research on Aging, Novato, California, United States of America
| | - Mario Sanhueza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Eugene Kim
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Maria de Haro
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Francesco DeGiacomo
- The Buck Institute for Research on Aging, Novato, California, United States of America
| | - Cameron Torcassi
- The Buck Institute for Research on Aging, Novato, California, United States of America
| | - Jennifer Holcomb
- The Buck Institute for Research on Aging, Novato, California, United States of America
| | - Juliette Gafni
- The Buck Institute for Research on Aging, Novato, California, United States of America
| | - Sean D. Mooney
- The Buck Institute for Research on Aging, Novato, California, United States of America
| | - Juan Botas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lisa M. Ellerby
- The Buck Institute for Research on Aging, Novato, California, United States of America
- * E-mail: (LME); (REH)
| | - Robert E. Hughes
- The Buck Institute for Research on Aging, Novato, California, United States of America
- * E-mail: (LME); (REH)
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Andreadi C, Cheung LK, Giblett S, Patel B, Jin H, Mercer K, Kamata T, Lee P, Williams A, McMahon M, Marais R, Pritchard C. The intermediate-activity (L597V)BRAF mutant acts as an epistatic modifier of oncogenic RAS by enhancing signaling through the RAF/MEK/ERK pathway. Genes Dev 2012; 26:1945-58. [PMID: 22892241 PMCID: PMC3435497 DOI: 10.1101/gad.193458.112] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 07/18/2012] [Indexed: 12/19/2022]
Abstract
(L597V)BRAF mutations are acquired somatically in human cancer samples and are frequently coincident with RAS mutations. Germline (L597V)BRAF mutations are also found in several autosomal dominant developmental conditions known as RASopathies, raising the important question of how the same mutation can contribute to both pathologies. Using a conditional knock-in mouse model, we show that endogenous expression of (L597V)Braf leads to approximately twofold elevated Braf kinase activity and weak activation of the Mek/Erk pathway. This is associated with induction of RASopathy hallmarks including cardiac abnormalities and facial dysmorphia but is not sufficient for tumor formation. We combined (L597V)Braf with (G12D)Kras and found that (L597V)Braf modified (G12D)Kras oncogenesis such that fibroblast transformation and lung tumor development were more reminiscent of that driven by the high-activity (V600E)Braf mutant. Mek/Erk activation levels were comparable with those driven by (V600E)Braf in the double-mutant cells, and the gene expression signature was more similar to that induced by (V600E)Braf than (G12D)Kras. However, unlike (V600E)Braf, Mek/Erk pathway activation was mediated by both Craf and Braf, and ATP-competitive RAF inhibitors induced paradoxical Mek/Erk pathway activation. Our data show that weak activation of the Mek/Erk pathway underpins RASopathies, but in cancer, (L597V)Braf epistatically modifies the transforming effects of driver oncogenes.
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Affiliation(s)
- Catherine Andreadi
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Lai-Kay Cheung
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Susan Giblett
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Bipin Patel
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Hong Jin
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Kathryn Mercer
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Tamihiro Kamata
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Pearl Lee
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Alexander Williams
- Bioinformatics Core, Gladstone Institute, University of California at San Francisco, San Francisco, California 94158, USA
| | - Martin McMahon
- Helen Diller Family Comprehensive Cancer Center, Department of Cell and Molecular Pharmacology, University of California at San Francisco, San Francisco, California 94143, USA
| | - Richard Marais
- Signal Transduction Team, The Institute of Cancer Research, Cancer Research UK Centre of Cell and Molecular Biology, London SW3 6JB, United Kingdom
| | - Catrin Pritchard
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
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48
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Jung MR, Lee TH, Bang MH, Kim H, Son Y, Chung DK, Kim J. Suppression of thymus- and activation-regulated chemokine (TARC/CCL17) production by 3-O-β-D-glucopyanosylspinasterol via blocking NF-κB and STAT1 signaling pathways in TNF-α and IFN-γ-induced HaCaT keratinocytes. Biochem Biophys Res Commun 2012; 427:236-41. [PMID: 22943853 DOI: 10.1016/j.bbrc.2012.08.087] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 08/18/2012] [Indexed: 12/19/2022]
Abstract
A phytosterol derivative, 3-O-β-D-glucopyanosylspinasterol (spinasterol-Glc) isolated from leaves of Stewartia koreana was reported to inhibit LPS-induced cytokine production in macrophage cells. Thymus and activation regulated chemokine (TARC/CCL17) is produced in response to pro-inflammatory cytokines in keratinocytes, which is implicated in the development of inflammatory skin diseases. In present study, we investigated the effect of spinasterol-Glc on production of TARC/CCL17 induced by TNF-α and IFN-γ in human HaCaT keratinocytes. Spinasterol-Glc inhibited the mRNA and protein expression of TARC/CCL17 induced by TNF-α/IFN-γ in a dose-dependent manner. Inhibitors of c-Raf-1, p38 MAPK, and JAK2, suppressed the TNF-α/IFN-γ-induced production of TARC/CCL17, and phosphorylation of these signaling molecules were attenuated by spinasterol-Glc. The compound also inhibited phosphorylation of IKKα/β and IκB-α, and reduced translocation of NF-κB to the nucleus. We demonstrated that spinasterol-Glc suppressed the NF-κB-driven and the GAS-driven expression of luciferase reporter gene induced by TNF-α and IFN-γ. In addition, spinasterol-Glc inhibited the DNA binding of NF-κB and STAT1 to its cognate binding site. These results suggest that spinasterol-Glc has effective inhibitory effects on production of TARC/CCL17 in keratinocytes via inhibition of NF-κB as well as STAT activation, and could be utilized for development of a potential therapeutic agent against skin inflammatory diseases.
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Affiliation(s)
- Mi-ra Jung
- Graduate School of Biotechnology and College of Life Sciences, Kyung Hee University, Yongin 446-701, Republic of Korea
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Subramanian RR, Yamakawa A. Combination therapy targeting Raf-1 and MEK causes apoptosis of HCT116 colon cancer cells. Int J Oncol 2012; 41:1855-62. [PMID: 22922669 DOI: 10.3892/ijo.2012.1602] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Accepted: 07/06/2012] [Indexed: 11/06/2022] Open
Abstract
Members of the Ras protooncogene family are mutated in approximately 75% of colon cancers. The Raf kinases (Raf-1, b-Raf and a-Raf) directly interact with Ras and serve as mediators of mitogenic signals. Expression of the constitutively active alleles of Raf or Ras gene families results in oncogenesis in a number of model systems. Previous studies emphasized the importance of Raf-1 and b-Raf in preventing apoptosis in addition to their roles in cell growth. In the present study, we examined whether inhibition of the Raf-1 or b-Raf kinase decreases cell growth and increases apoptosis in colon cancer cells. c-Raf and b-Raf were depleted in colon cancer cell lines, such as HCT116, HT29 and Colo205, containing Ras or b-Raf mutations by RNA interference (RNAi). The results showed that colon cancer cells with activating Ras mutations undergo apoptosis following Raf-1 inhibition, as determined by cell cycle analysis and the release of cytochrome c. Moreover, in b-Raf mutant colon cancers, the inhibition of b-Raf as compared to Raf-1 is crucial for cancer cell death. There is increasing evidence for both MEK-independent Raf signaling and Raf-independent MEK signaling. Thus, we investigated whether targeting multiple points of the mitogen-activated protein kinase (MAPK) pathway with a MEK inhibitor and Raf RNAi increases cancer cell death. The results showed that combination therapy, inhibiting Raf and MEK kinases simultaneously, increased apoptosis in colon cancer cells. Taken together, our data demonstrate that combination therapy targeting the MAPK pathway at two distinct points, Raf kinase and MEK, has greater efficacy in increasing cancer cell death and is likely to improve therapeutic outcomes for patients.
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Affiliation(s)
- Romesh R Subramanian
- Department of Cancer Biology, Dana-Farber Cancer Institute and Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.
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Protein kinases of the Hippo pathway: regulation and substrates. Semin Cell Dev Biol 2012; 23:770-84. [PMID: 22898666 DOI: 10.1016/j.semcdb.2012.07.002] [Citation(s) in RCA: 180] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 07/31/2012] [Indexed: 01/30/2023]
Abstract
The "Hippo" signaling pathway has emerged as a major regulator of cell proliferation and survival in metazoans. The pathway, as delineated by genetic and biochemical studies in Drosophila, consists of a kinase cascade regulated by cell-cell contact and cell polarity that inhibits the transcriptional coactivator Yorkie and its proliferative, anti-differentiation, antiapoptotic transcriptional program. The core pathway components are the GC kinase Hippo, which phosphorylates the noncatalytic polypeptide Mats/Mob1 and, with the assistance of the scaffold protein Salvador, phosphorylates the ndr-family kinase Lats. In turn phospho-Lats, after binding to phospho-Mats, autoactivates and phosphorylates Yorkie, resulting in its nuclear exit. Hippo also uses the scaffold protein Furry and a different Mob protein to control another ndr-like kinase, the morphogenetic regulator Tricornered. Architecturally homologous kinase cascades consisting of a GC kinase, a Mob protein, a scaffolding polypeptide and an ndr-like kinase are well described in yeast; in Saccharomyces cerevisiae, e.g., the MEN pathway promotes mitotic exit whereas the RAM network, using a different GC kinase, Mob protein, scaffold and ndr-like kinase, regulates cell polarity and morphogenesis. In mammals, the Hippo orthologs Mst1 and Mst2 utilize the Salvador ortholog WW45/Sav1 and other scaffolds to regulate the kinases Lats1/Lats2 and ndr1/ndr2. As in Drosophila, murine Mst1/Mst2, in a redundant manner, negatively regulate the Yorkie ortholog YAP in the epithelial cells of the liver and gut; loss of both Mst1 and Mst2 results in hyperproliferation and tumorigenesis that can be largely negated by reduction or elimination of YAP. Despite this conservation, considerable diversification in pathway composition and regulation is already evident; in skin, e.g., YAP phosphorylation is independent of Mst1Mst2 and Lats1Lats2. Moreover, in lymphoid cells, Mst1/Mst2, under the control of the Rap1 GTPase and independent of YAP, promotes integrin clustering, actin remodeling and motility while restraining the proliferation of naïve T cells. This review will summarize current knowledge of the structure and regulation of the kinases Hippo/Mst1&2, their noncatalytic binding partners, Salvador and the Rassf polypeptides, and their major substrates Warts/Lats1&2, Trc/ndr1&2, Mats/Mob1 and FOXO.
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