51
|
Dai H, Chen H, Liu W, You Y, Tan J, Yang A, Lai X, Bie P. Effects of Raf kinase inhibitor protein expression on pancreatic cancer cell growth and motility: an in vivo and in vitro study. J Cancer Res Clin Oncol 2016; 142:2107-17. [PMID: 27444299 DOI: 10.1007/s00432-016-2206-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/08/2016] [Indexed: 01/05/2023]
Abstract
PURPOSE Raf kinase inhibitor protein (RKIP) is a tumor suppressor that inhibits cell growth and metastasis of malignant tumors. Pancreatic cancer is a leading cause of cancer death with a low survival rate. RKIP expression and its role in tumorigenesis and metastasis in pancreatic cancer are poorly understood. The aims of our study were to assess the effects of RKIP on pancreatic carcinoma cells in vitro and in tumor tissues in vivo. METHODS This study included 84 patients with histologically confirmed pancreatic adenocarcinoma. The expression levels of RKIP were measured in pancreatic cancer tissues and adjacent normal tissues using real-time PCR and immunohistochemistry. Overexpression plasmid of RKIP was transfected into SW1990 and AsPC-1 cell lines, and the effects on cell proliferation were studied using a Cell Counting Kit-8 assay. MEK1/2 and ERK1/2 were detected by Western blot and immunofluorescence assay. RESULTS Results showed a reduced expression of RKIP in pancreatic carcinoma tissues compared with adjacent normal tissues, which closely correlated with patient outcomes. Overexpression of RKIP suppressed cell proliferation and promoted apoptosis in cultured SW1990 and AsPC-1 cell lines. Transwell assay showed RKIP can inhibit cell migration and invasion, and in vivo RKIP can suppress tumorigenesis by diminishing the volume of the tumors. CONCLUSIONS In conclusion, expression of RKIP is closely correlated with the survival of pancreatic cancer patients. RKIP can inhibit pancreatic adenocarcinoma cells proliferation, activities of migration and invasion, through downregulating Raf-1-MEK1/2-ERK1/2 signaling pathway.
Collapse
Affiliation(s)
- Haisu Dai
- Department of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 404100, People's Republic of China
| | - Haowei Chen
- Department of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 404100, People's Republic of China
| | - Wei Liu
- Department of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 404100, People's Republic of China
| | - Yu You
- Department of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 404100, People's Republic of China
| | - Jiaxin Tan
- Department of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 404100, People's Republic of China
| | - Aigang Yang
- Department of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 404100, People's Republic of China
| | - Xiangdong Lai
- Department of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 404100, People's Republic of China
| | - Ping Bie
- Department of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, 404100, People's Republic of China.
| |
Collapse
|
52
|
Raguz J, Jeric I, Niault T, Nowacka JD, Kuzet SE, Rupp C, Fischer I, Biggi S, Borsello T, Baccarini M. Epidermal RAF prevents allergic skin disease. eLife 2016; 5. [PMID: 27431613 PMCID: PMC4951198 DOI: 10.7554/elife.14012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 06/13/2016] [Indexed: 01/08/2023] Open
Abstract
The RAS pathway is central to epidermal homeostasis, and its activation in tumors or in Rasopathies correlates with hyperproliferation. Downstream of RAS, RAF kinases are actionable targets regulating keratinocyte turnover; however, chemical RAF inhibitors paradoxically activate the pathway, promoting epidermal proliferation. We generated mice with compound epidermis-restricted BRAF/RAF1 ablation. In these animals, transient barrier defects and production of chemokines and Th2-type cytokines by keratinocytes cause a disease akin to human atopic dermatitis, characterized by IgE responses and local and systemic inflammation. Mechanistically, BRAF and RAF1 operate independently to balance MAPK signaling: BRAF promotes ERK activation, while RAF1 dims stress kinase activation. In vivo, JNK inhibition prevents disease onset, while MEK/ERK inhibition in mice lacking epidermal RAF1 phenocopies it. These results support a primary role of keratinocytes in the pathogenesis of atopic dermatitis, and the animals lacking BRAF and RAF1 in the epidermis represent a useful model for this disease.
Collapse
Affiliation(s)
- Josipa Raguz
- Department of Microbiology, Immunology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Ines Jeric
- Department of Microbiology, Immunology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Theodora Niault
- Department of Microbiology, Immunology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Joanna Daniela Nowacka
- Department of Microbiology, Immunology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Sanya Eduarda Kuzet
- Department of Microbiology, Immunology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Christian Rupp
- Department of Microbiology, Immunology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Irmgard Fischer
- Department of Microbiology, Immunology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Silvia Biggi
- Department of Neuroscience, Istituto Di Ricerche Farmacologiche Mario Negri, Milano, Italy.,Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milano, Italy
| | - Tiziana Borsello
- Department of Neuroscience, Istituto Di Ricerche Farmacologiche Mario Negri, Milano, Italy.,Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milano, Italy
| | - Manuela Baccarini
- Department of Microbiology, Immunology and Genetics, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| |
Collapse
|
53
|
Fey D, Matallanas D, Rauch J, Rukhlenko OS, Kholodenko BN. The complexities and versatility of the RAS-to-ERK signalling system in normal and cancer cells. Semin Cell Dev Biol 2016; 58:96-107. [PMID: 27350026 DOI: 10.1016/j.semcdb.2016.06.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 06/18/2016] [Indexed: 12/19/2022]
Abstract
The intricate dynamic control and plasticity of RAS to ERK mitogenic, survival and apoptotic signalling has mystified researches for more than 30 years. Therapeutics targeting the oncogenic aberrations within this pathway often yield unsatisfactory, even undesired results, as in the case of paradoxical ERK activation in response to RAF inhibition. A direct approach of inhibiting single oncogenic proteins misses the dynamic network context governing the network signal processing. In this review, we discuss the signalling behaviour of RAS and RAF proteins in normal and in cancer cells, and the emerging systems-level properties of the RAS-to-ERK signalling network. We argue that to understand the dynamic complexities of this control system, mathematical models including mechanistic detail are required. Looking into the future, these dynamic models will build the foundation upon which more effective, rational approaches to cancer therapy will be developed.
Collapse
Affiliation(s)
- Dirk Fey
- Systems Biology Ireland, UCD School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
| | - David Matallanas
- Systems Biology Ireland, UCD School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Jens Rauch
- Systems Biology Ireland, UCD School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Oleksii S Rukhlenko
- Systems Biology Ireland, UCD School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Boris N Kholodenko
- Systems Biology Ireland, UCD School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland; Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
| |
Collapse
|
54
|
Gerarduzzi C, He Q, Zhai B, Antoniou J, Di Battista JA. Prostaglandin E2-Dependent Phosphorylation of RAS Inhibition 1 (RIN1) at Ser 291 and 292 Inhibits Transforming Growth Factor-β-Induced RAS Activation Pathway in Human Synovial Fibroblasts: Role in Cell Migration. J Cell Physiol 2016; 232:202-15. [PMID: 27137893 DOI: 10.1002/jcp.25412] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 04/28/2016] [Indexed: 12/27/2022]
Abstract
Prostaglandin E2 (PGE2 )-stimulated G-protein-coupled receptor (GPCR) activation inhibits pro-fibrotic TGFβ-dependent stimulation of human fibroblast to myofibroblast transition (FMT), though the precise molecular mechanisms are not fully understood. In the present study, we describe the PGE2 -dependent suppression and reversal of TGFβ-induced events such as α-sma expression, stress fiber formation, and Ras/Raf/ERK/MAPK pathway-dependent activation of myofibroblast migration. In order to elucidate post-ligand-receptor signaling pathways, we identified a predominant PKA phosphorylation motif profile in human primary fibroblasts after treatment with exogenous PGE2 (EC50 30 nM, Vmax 100 nM), mimicked by the adenyl cyclase activator forskolin (EC50 5 μM, Vmax 10 μM). We used a global phosphoproteomic approach to identify a 2.5-fold difference in PGE2 -induced phosphorylation of proteins containing the PKA motif. Deducing the signaling pathway of our migration data, we identified Ras inhibitor 1 (RIN1) as a substrate, whereby PGE2 induced its phosphorylation at Ser291 and at Ser292 by a 5.4- and 4.8-fold increase, respectively. In a series of transient and stable over expression studies in HEK293T and HeLa cells using wild-type (wt) and mutant RIN1 (Ser291/292Ala) or Ras constructs and siRNA knock-down experiments, we showed that PGE2 -dependent phosphorylation of RIN1 resulted in the abrogation of TGFβ-induced Ras/Raf signaling activation and subsequent downstream blockade of cellular migration, emphasizing the importance of such phosphosites in PGE2 suppression of wound closure. Overexpression experiments in tandem with pull-down assays indicated that specific Ser291/292 phosphorylation of RIN1 favored binding to activated Ras. In principal, understanding PGE2 -GPCR activated signaling pathways mitigating TGFβ-induced fibrosis may lead to more evidence-based treatments against the disease. J. Cell. Physiol. 232: 202-215, 2017. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Casimiro Gerarduzzi
- Renal Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts. .,Departments of Experimental Medicine, McGill University, Montréal, QC, Canada.
| | - QingWen He
- Departments of Medicine and Experimental Medicine, McGill University, Montréal, QC, Canada
| | - Beibei Zhai
- Departments of Experimental Medicine, McGill University, Montréal, QC, Canada
| | - John Antoniou
- Department of Orthopaedic Surgery, Jewish General Hospital, Montréal, QC, Canada
| | - John A Di Battista
- Departments of Medicine and Experimental Medicine, McGill University, Montréal, QC, Canada
| |
Collapse
|
55
|
Lappas M. RAF1 is increased in labouring myometrium and modulates inflammation-induced pro-labour mediators. Reproduction 2016; 151:411-20. [DOI: 10.1530/rep-15-0607] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 01/25/2016] [Indexed: 01/25/2023]
Abstract
Inflammation plays a central role in the terminal process of human labour and delivery, including myometrial contractions. RAF1 proto-oncogene serine/threonine-protein kinase (RAF1) can activate ERK (official gene symbolMAPK1) and/or nuclear factor-kappa B (NF-κB) to regulate genes involved in inflammation. There are, however, no studies on the role of RAF1 in the processes of human labour and delivery. Thus, the aims of this study were to determine the effect of i) human labour and pro-inflammatory cytokines interleukin 1 beta (IL1B) and tumour necrosis factor (TNF) alpha on RAF1 protein expression in myometrium and ii) siRNA knockdown ofRAF1on pro-inflammatory and pro-labour mediators in human myometrial primary cells. Term labour was associated with an increase in RAF1 protein expression. Furthermore, RAF1 protein expression was increased in myometrial cells treated with IL1B and TNF, two likely factors contributing to preterm birth. Knockdown ofRAF1by siRNA in primary myometrial cells significantly decreased IL1B- and TNF-inducedIL1A, IL1B, IL6,(C-X-C motif) ligand 8 (CXCL8)and chemokine (C-C motif) ligand 2 (CCL2) mRNA abundance and IL6, IL8 and CCL2; prostaglandin-endoperoxide synthase 2 (PTGS2) mRNA levels and prostaglandin PGF2αrelease; and NF-κB activation. Furthermore,RAF1knockdown was associated with decreased activation of ERK in the presence of IL1B but not TNF. Concordantly, the ERK inhibitor U0126 significantly decreased IL1B-inducedIL6,CXCL8,CCL2andPTGS2mRNA abundance; IL6, CXCL8, CCL2 and PGF2αrelease; and NF-κB activation. In conclusion, IL1B induces the expression and secretion of pro-labour mediators through the RAF1–MAPK1–NF-κB signalling pathway. TNF, on the other hand, regulates pro-labour mediators through the RAF1–NF-κB signalling pathway via an MAPK1-independent mechanism.
Collapse
|
56
|
Choi I, Kim B, Byun JW, Baik SH, Huh YH, Kim JH, Mook-Jung I, Song WK, Shin JH, Seo H, Suh YH, Jou I, Park SM, Kang HC, Joe EH. LRRK2 G2019S mutation attenuates microglial motility by inhibiting focal adhesion kinase. Nat Commun 2015; 6:8255. [PMID: 26365310 PMCID: PMC4647842 DOI: 10.1038/ncomms9255] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 08/03/2015] [Indexed: 01/20/2023] Open
Abstract
In response to brain injury, microglia rapidly extend processes that isolate lesion sites and protect the brain from further injury. Here we report that microglia carrying a pathogenic mutation in the Parkinson's disease (PD)-associated gene, G2019S-LRRK2 (GS-Tg microglia), show retarded ADP-induced motility and delayed isolation of injury, compared with non-Tg microglia. Conversely, LRRK2 knockdown microglia are highly motile compared with control cells. In our functional assays, LRRK2 binds to focal adhesion kinase (FAK) and phosphorylates its Thr–X–Arg/Lys (TXR/K) motif(s), eventually attenuating FAK activity marked by decreased pY397 phosphorylation (pY397). GS-LRRK2 decreases the levels of pY397 in the brain, microglia and HEK cells. In addition, treatment with an inhibitor of LRRK2 kinase restores pY397 levels, decreased pTXR levels and rescued motility of GS-Tg microglia. These results collectively suggest that G2019S mutation of LRRK2 may contribute to the development of PD by inhibiting microglial response to brain injury. In response to brain injury, microglia extend processes to isolate the lesion. Here Choi et al. show that microglia expressing a pathogenic mutation in the Parkinson's disease-associated LRRK2 gene show reduced motility and delayed lesion isolation in vitro and in vivo due to attenuated focal adhesion kinase activity.
Collapse
Affiliation(s)
- Insup Choi
- Department of Biomedical Sciences, Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea
| | - Beomsue Kim
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea
| | - Ji-Won Byun
- Department of Biomedical Sciences, Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea
| | - Sung Hoon Baik
- Department of Biochemistry and Biomedical Sciences, College of Medicine, Seoul National University, Seoul 110-799, Korea
| | - Yun Hyun Huh
- Bio Imaging and Cell Dynamics Research Center, School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Jong-Hyeon Kim
- Department of Biomedical Sciences, Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea
| | - Inhee Mook-Jung
- Department of Biochemistry and Biomedical Sciences, College of Medicine, Seoul National University, Seoul 110-799, Korea
| | - Woo Keun Song
- Bio Imaging and Cell Dynamics Research Center, School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea
| | - Joo-Ho Shin
- Division of Pharmacology, Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Gyeonggi-do 440-746, Korea
| | - Hyemyung Seo
- Department of Molecular and Life Sciences, Hanyang University, Ansan 426-791, Korea
| | - Young Ho Suh
- Department of Biomedical Sciences, Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea
| | - Ilo Jou
- Department of Biomedical Sciences, Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea
| | - Sang Myun Park
- Department of Biomedical Sciences, Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea
| | - Ho Chul Kang
- Department of Physiology, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea
| | - Eun-Hye Joe
- Department of Biomedical Sciences, Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Department of Brain Science, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea.,Brain Disease Research Center, Ajou University School of Medicine, Suwon, Gyeonggi-do 443-380, Korea
| |
Collapse
|
57
|
Advani SJ, Camargo MF, Seguin L, Mielgo A, Anand S, Hicks AM, Aguilera J, Franovic A, Weis SM, Cheresh DA. Kinase-independent role for CRAF-driving tumour radioresistance via CHK2. Nat Commun 2015; 6:8154. [PMID: 26333361 PMCID: PMC4559870 DOI: 10.1038/ncomms9154] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 07/24/2015] [Indexed: 12/19/2022] Open
Abstract
Although oncology therapy regimens commonly include radiation and genotoxic drugs, tumour cells typically develop resistance to these interventions. Here we report that treatment of tumours with ionizing radiation or genotoxic drugs drives p21-activated kinase 1 (PAK1)-mediated phosphorylation of CRAF on Serine 338 (pS338) triggering a kinase-independent mechanism of DNA repair and therapeutic resistance. CRAF pS338 recruits CHK2, a cell cycle checkpoint kinase involved in DNA repair, and promotes CHK2 phosphorylation/activation to enhance the tumour cell DNA damage response. Accordingly, a phospho-mimetic mutant of CRAF (S338D) is sufficient to induce the CRAF/CHK2 association enhancing tumour radioresistance, while an allosteric CRAF inhibitor sensitizes tumour cells to ionizing radiation or genotoxic drugs. Our findings establish a role for CRAF in the DNA damage response that is independent from its canonical function as a kinase. Tumors hijack cellular pathways to evade the effects of cancer therapy. Here, Advani et al. show that DNA damage-induced phosphorylation of CRAF Serine 338 triggers DNA repair by recruiting CHK2, highlighting a role for CRAF independent from its canonical function as a kinase.
Collapse
Affiliation(s)
- Sunil J Advani
- Department of Radiation Medicine and Applied Sciences at the UC San Diego Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Maria Fernanda Camargo
- Department of Pathology at the UC San Diego Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, 3855 Health Science Drive, La Jolla, California 92037, USA
| | - Laetitia Seguin
- Department of Pathology at the UC San Diego Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, 3855 Health Science Drive, La Jolla, California 92037, USA
| | - Ainhoa Mielgo
- Department of Pathology at the UC San Diego Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, 3855 Health Science Drive, La Jolla, California 92037, USA
| | - Sudarshan Anand
- Department of Pathology at the UC San Diego Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, 3855 Health Science Drive, La Jolla, California 92037, USA
| | - Angel M Hicks
- Department of Radiation Medicine and Applied Sciences at the UC San Diego Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Joseph Aguilera
- Department of Radiation Medicine and Applied Sciences at the UC San Diego Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Aleksandra Franovic
- Department of Pathology at the UC San Diego Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, 3855 Health Science Drive, La Jolla, California 92037, USA
| | - Sara M Weis
- Department of Pathology at the UC San Diego Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, 3855 Health Science Drive, La Jolla, California 92037, USA
| | - David A Cheresh
- Department of Pathology at the UC San Diego Moores Cancer Center and Sanford Consortium for Regenerative Medicine, University of California, San Diego, 3855 Health Science Drive, La Jolla, California 92037, USA
| |
Collapse
|
58
|
Activation of RAF1 (c-RAF) by the Marine Alkaloid Lasonolide A Induces Rapid Premature Chromosome Condensation. Mar Drugs 2015; 13:3625-39. [PMID: 26058013 PMCID: PMC4483648 DOI: 10.3390/md13063625] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/18/2015] [Accepted: 05/26/2015] [Indexed: 01/12/2023] Open
Abstract
Lasonolide A (LSA), a potent antitumor polyketide from the marine sponge, Forcepia sp., induces rapid and reversible protein hyperphosphorylation and premature chromosome condensation (PCC) at nanomolar concentrations independent of cyclin-dependent kinases. To identify cellular targets of LSA, we screened 2951 shRNAs targeting a pool of human kinases and phosphatases (1140 RefSeqs) to identify genes that modulate PCC in response to LSA. This led to the identification of RAF1 (C-RAF) as a mediator of LSA-induced PCC, as shRNAs against RAF1 conferred resistance to LSA. We found that LSA induced RAF1 phosphorylation on Serine 338 within minutes in human colorectal carcinoma HCT-116, ovarian carcinoma OVCAR-8, and Burkitt’s lymphoma CA46 cell lines. RAF1 depletion by siRNAs attenuated LSA-induced PCC in HCT-116 and OVCAR-8 cells. Furthermore, mouse embryonic fibroblasts (MEF) with homozygous deletion in Raf1, but not deletion in the related kinase Braf, were resistant to LSA-induced PCC. Complementation of Raf1−/− MEFs with wild-type human RAF1, but not with kinase-dead RAF1 mutant, restored LSA-induced PCC. Finally, the Raf inhibitor sorafenib, but not the MEK inhibitor AZD6244, effectively suppressed LSA-induced PCC. Our findings implicate a previously unknown, MAPK-independent role of RAF1 in chromatin condensation and potent activation of this pathway by LSA.
Collapse
|
59
|
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.
Collapse
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
| |
Collapse
|
60
|
Lipid rafts and raft-mediated supramolecular entities in the regulation of CD95 death receptor apoptotic signaling. Apoptosis 2015; 20:584-606. [DOI: 10.1007/s10495-015-1104-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
61
|
Samatar AA, Poulikakos PI. Targeting RAS-ERK signalling in cancer: promises and challenges. Nat Rev Drug Discov 2015; 13:928-42. [PMID: 25435214 DOI: 10.1038/nrd4281] [Citation(s) in RCA: 798] [Impact Index Per Article: 88.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The RAS-RAF-MEK-ERK signalling pathway is hyperactivated in a high percentage of tumours, most frequently owing to activating mutations of the KRAS, NRAS and BRAF genes. Recently, the use of compounds targeting components of ERK signalling, such as RAF or MEK inhibitors, has led to substantial improvement in clinical outcome in metastatic melanoma and has shown promising clinical activity in additional tumour types. However, response rates are highly variable and the efficacy of these drugs is primarily limited by the development of resistance. Both intrinsic and acquired resistance to RAF and MEK inhibitors are frequently associated with the persistence of ERK signalling in the presence of the drug, implying the need for more innovative approaches to target the pathway.
Collapse
Affiliation(s)
- Ahmed A Samatar
- TheraMet Biosciences, 6 Jacob Drive, Princeton Junction, New Jersey 08550, USA
| | - Poulikos I Poulikakos
- Department of Oncological Sciences and Department of Dermatology, The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, New York 10029, USA
| |
Collapse
|
62
|
The effect of antenatal depression and selective serotonin reuptake inhibitor treatment on nerve growth factor signaling in human placenta. PLoS One 2015; 10:e0116459. [PMID: 25611484 PMCID: PMC4303267 DOI: 10.1371/journal.pone.0116459] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/10/2014] [Indexed: 02/05/2023] Open
Abstract
Depressive symptoms during pregnancy are common and may have impact on the developing child. Selective serotonin reuptake inhibitors (SSRIs) are the most prescribed antidepressant treatment, but unfortunately, these treatments can also negatively affect the behavioral development and health of a child during pregnancy. In addition, serotonin (5-HT) exerts neurotrophic actions with thus far not fully known effects in the offspring. The neurotrophic growth factor (NGF) is involved in neuronal cell survival and differentiation, and altered placenta levels have been found to increase the risk for pregnancy complications, similar to those found in women treated with SSRIs. We therefore investigated whether the NGF signaling pathway was altered in the placenta from women treated with SSRIs (n = 12) and compared them with placenta from depressed (n = 12) and healthy mothers (n = 12). Results from immunohistochemical stainings revealed that placental NGF protein levels of SSRI-treated women were increased in both trophoblasts and endothelial cells compared with depressed and control women. In addition, downstream of the NGF receptor TrkA, increased levels of the signaling proteins ROCK2 and phosphorylated Raf-1 were found in stromal cells and a tendency towards increased levels of ROCK2 in trophoblasts and endothelial cells in SSRI-treated women when compared to healthy controls. SSRI-treated women also displayed increased levels of phosphorylated ROCK2 in all placental cell types studied in comparison with depressed and control women. Interestingly, in placental endothelial cells from depressed women, NGF levels were significantly lower compared to control women, but ROCK2 levels were increased compared with control and SSRI-treated women. Taken together, these results show that the NGF signaling and downstream pathways in the placenta are affected by SSRI treatment and/or antenatal depression. This might lead to an altered placental function, although the clinical relevance of our findings still needs to be investigated.
Collapse
|
63
|
An S, Yang Y, Ward R, Liu Y, Guo XX, Xu TR. Raf-interactome in tuning the complexity and diversity of Raf function. FEBS J 2014; 282:32-53. [PMID: 25333451 DOI: 10.1111/febs.13113] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/06/2014] [Accepted: 10/14/2014] [Indexed: 12/23/2022]
Abstract
Raf kinases have been intensely studied subsequent to their discovery 30 years ago. The Ras-Raf-mitogen-activated protein kinase/extracellular signal-regulated kinase kinase-extracellular signal-regulated kinase/mitogen-activated protein kinase (Ras-Raf-MEK-ERK/MAPK) signaling pathway is at the heart of the signaling networks that control many fundamental cellular processes and Raf kinases takes centre stage in the MAPK pathway, which is now appreciated to be one of the most common sources of the oncogenic mutations in cancer. The dependency of tumors on this pathway has been clearly demonstrated by targeting its key nodes; however, blockade of the central components of the MAPK pathway may have some unexpected side effects. Over recent years, the Raf-interactome or Raf-interacting proteins have emerged as promising targets for protein-directed cancer therapy. This review focuses on the diversity of Raf-interacting proteins and discusses the mechanisms by which these proteins regulate Raf function, as well as the implications of targeting Raf-interacting proteins in the treatment of human cancer.
Collapse
Affiliation(s)
- Su An
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan, China
| | | | | | | | | | | |
Collapse
|
64
|
Huang PY, Balmain A. Modeling cutaneous squamous carcinoma development in the mouse. Cold Spring Harb Perspect Med 2014; 4:a013623. [PMID: 25183851 DOI: 10.1101/cshperspect.a013623] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cutaneous squamous cell carcinoma (SCC) is one of the most common cancers in Caucasian populations and is associated with a significant risk of morbidity and mortality. The classic mouse model for studying SCC involves two-stage chemical carcinogenesis, which has been instrumental in the evolution of the concept of multistage carcinogenesis, as widely applied to both human and mouse cancers. Much is now known about the sequence of biological and genetic events that occur in this skin carcinogenesis model and the factors that can influence the course of tumor development, such as perturbations in the oncogene/tumor-suppressor signaling pathways involved, the nature of the target cell that acquires the first genetic hit, and the role of inflammation. Increasingly, studies of tumor-initiating cells, malignant progression, and metastasis in mouse skin cancer models will have the potential to inform future approaches to treatment and chemoprevention of human squamous malignancies.
Collapse
Affiliation(s)
- Phillips Y Huang
- Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, California 94158
| | - Allan Balmain
- Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, California 94158
| |
Collapse
|
65
|
Brown WS, Khalili JS, Rodriguez-Cruz TG, Lizee G, McIntyre BW. B-Raf regulation of integrin α4β1-mediated resistance to shear stress through changes in cell spreading and cytoskeletal association in T cells. J Biol Chem 2014; 289:23141-23153. [PMID: 24936068 DOI: 10.1074/jbc.m114.562918] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The regulation of integrin-mediated adhesion is of vital importance to adaptive and innate immunity. Integrins are versatile proteins and mediate T cell migration and trafficking by binding to extracellular matrix or other cells as well as initiating intracellular signaling cascades promoting survival or activation. The MAPK pathway is known to be downstream from integrins and to regulate survival, differentiation, and motility. However, secondary roles for canonical MAPK pathway members are being discovered. We show that chemical inhibition of RAF by sorafenib or shRNA-mediated knockdown of B-Raf reduces T cell resistance to shear stress to α4β1 integrin ligands vascular cell adhesion molecule 1 (VCAM-1) and fibronectin, whereas inhibition of MEK/ERK by U0126 had no effect. Microscopy showed that RAF inhibition leads to significant inhibition of T cell spreading on VCAM-1. The association of α4β1 integrin with the actin cytoskeleton was shown to be dependent on B-Raf activity or expression, whereas α4β1 integrin affinity for soluble VCAM-1 was not. These effects were shown to be specific for α4β1 integrin and not other integrins, such as α5β1 or LFA-1, or a variety of membrane proteins. We demonstrate a novel role for B-Raf in the selective regulation of α4β1 integrin-mediated adhesion.
Collapse
Affiliation(s)
- Wells S Brown
- Department of Immunology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and
| | - Jahan S Khalili
- Department of Melanoma Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Tania G Rodriguez-Cruz
- Department of Melanoma Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Greg Lizee
- Department of Melanoma Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Bradley W McIntyre
- Department of Immunology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and.
| |
Collapse
|
66
|
Romano D, Nguyen LK, Matallanas D, Halasz M, Doherty C, Kholodenko BN, Kolch W. Protein interaction switches coordinate Raf-1 and MST2/Hippo signalling. Nat Cell Biol 2014; 16:673-84. [DOI: 10.1038/ncb2986] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 05/08/2014] [Indexed: 12/19/2022]
|
67
|
"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.
Collapse
|
68
|
Matsumoto H, Murakami Y, Kataoka K, Lin H, Connor KM, Miller JW, Zhou D, Avruch J, Vavvas DG. Mammalian STE20-like kinase 2, not kinase 1, mediates photoreceptor cell death during retinal detachment. Cell Death Dis 2014; 5:e1269. [PMID: 24874741 PMCID: PMC4047884 DOI: 10.1038/cddis.2014.218] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 04/14/2014] [Indexed: 12/28/2022]
Abstract
Photoreceptor cell death is the definitive cause of vision loss in retinal detachment (RD). Mammalian STE20-like kinase (MST) is a master regulator of both cell death and proliferation and a critical factor in development and tumorigenesis. However, to date the role of MST in neurodegeneration has not been fully explored. Utilizing MST1−/− and MST2−/− mice we identified MST2, but not MST1, as a regulator of photoreceptor cell death in a mouse model of RD. MST2−/− mice demonstrated significantly decreased photoreceptor cell death and outer nuclear layer (ONL) thinning after RD. Additionally, caspase-3 activation was attenuated in MST2−/− mice compared to control mice after RD. The transcription of p53 upregulated modulator of apoptosis (PUMA) and Fas was also reduced in MST2−/− mice post-RD. Retinas of MST2−/− mice displayed suppressed nuclear relocalization of phosphorylated YAP after RD. Consistent with the reduction of photoreceptor cell death, MST2−/− mice showed decreased levels of proinflammatory cytokines such as monocyte chemoattractant protein 1 and interleukin 6 as well as attenuated inflammatory CD11b cell infiltration during the early phase of RD. These results identify MST2, not MST1, as a critical regulator of caspase-mediated photoreceptor cell death in the detached retina and indicate its potential as a future neuroprotection target.
Collapse
Affiliation(s)
- H Matsumoto
- Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | - Y Murakami
- Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | - K Kataoka
- Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | - H Lin
- Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | - K M Connor
- Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | - J W Miller
- Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | - D Zhou
- State Key Laboratory of Stress Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - J Avruch
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - D G Vavvas
- Retina Service, Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| |
Collapse
|
69
|
Pellicioli ACA, Martins MD, Dillenburg CS, Marques MM, Squarize CH, Castilho RM. Laser phototherapy accelerates oral keratinocyte migration through the modulation of the mammalian target of rapamycin signaling pathway. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:028002. [PMID: 24531144 DOI: 10.1117/1.jbo.19.2.028002] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 01/17/2014] [Indexed: 06/03/2023]
Abstract
Keratinocytes play a central role in wound healing by responding to tissue injury through the activation of cellular proliferation and migration. Current clinical evidence suggests that the laser phototherapy (LPT) accelerates wound healing in a variety of oral diseases; however, the molecular mechanisms involved in response to LPT are not fully understood. Oral keratinocytes (NOK-SI) maintained under nutritional-deficit culture medium (2% fetal bovine serum) were irradiated with InGaAlP laser (660 nm; 40 mW; 0.04 cm2 spot size) in punctual and contact modes. The energy densities used were 4 and 20 J/cm2 corresponding to 4 and 20 s of exposure times and 0.16 and 0.8 J of energy per point, respectively. Three sessions of irradiations were applied with 6-h intervals. Further, the impact of LPT over cellular migration, proliferation, and activation of the mammalian target of rapamycin (mTOR) pathway, known to play a major role in epithelial migration and wound healing, was analyzed. Compared with control cells, the LPT-treated cells showed accelerated cellular migration without any changes in proliferation. Furthermore, LPT resulted in an increase in the phospho-S6 ribosomal protein, indicating activation of the mTOR signaling pathway. Collectively, these findings suggest that the LPT activates mTOR signaling pathway, promotes epithelial cell migration, and accelerates healing of oral mucosa.
Collapse
Affiliation(s)
- Ana Carolina Amorim Pellicioli
- Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul 90035-003, Brazil
| | - Manoela Domingues Martins
- Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul 90035-003, Brazil
| | - Caroline Siviero Dillenburg
- Universidade Federal do Rio Grande do Sul, School of Dentistry, Department of Oral Pathology, Porto Alegre, Rio Grande do Sul 90035-003, Brazil
| | - Márcia Martins Marques
- University of São Paulo, School of Dentistry, Department of Dentistry, São Paulo, São Paulo 05508-000, Brazil
| | - Cristiane H Squarize
- University of Michigan, School of Dentistry, Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, Ann Arbor, Michigan 48109-1078
| | - Rogerio M Castilho
- University of Michigan, School of Dentistry, Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, Ann Arbor, Michigan 48109-1078
| |
Collapse
|
70
|
Rosselli-Murai LK, Almeida LO, Zagni C, Galindo-Moreno P, Padial-Molina M, Volk SL, Murai MJ, Rios HF, Squarize CH, Castilho RM. Periostin responds to mechanical stress and tension by activating the MTOR signaling pathway. PLoS One 2013; 8:e83580. [PMID: 24349533 PMCID: PMC3862800 DOI: 10.1371/journal.pone.0083580] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 11/06/2013] [Indexed: 11/28/2022] Open
Abstract
Current knowledge about Periostin biology has expanded from its recognized functions in embryogenesis and bone metabolism to its roles in tissue repair and remodeling and its clinical implications in cancer. Emerging evidence suggests that Periostin plays a critical role in the mechanism of wound healing; however, the paracrine effect of Periostin in epithelial cell biology is still poorly understood. We found that epithelial cells are capable of producing endogenous Periostin that, unlike mesenchymal cell, cannot be secreted. Epithelial cells responded to Periostin paracrine stimuli by enhancing cellular migration and proliferation and by activating the mTOR signaling pathway. Interestingly, biomechanical stimulation of epithelial cells, which simulates tension forces that occur during initial steps of tissue healing, induced Periostin production and mTOR activation. The molecular association of Periostin and mTOR signaling was further dissected by administering rapamycin, a selective pharmacological inhibitor of mTOR, and by disruption of Raptor and Rictor scaffold proteins implicated in the regulation of mTORC1 and mTORC2 complex assembly. Both strategies resulted in ablation of Periostin-induced mitogenic and migratory activity. These results indicate that Periostin-induced epithelial migration and proliferation requires mTOR signaling. Collectively, our findings identify Periostin as a mechanical stress responsive molecule that is primarily secreted by fibroblasts during wound healing and expressed endogenously in epithelial cells resulting in the control of cellular physiology through a mechanism mediated by the mTOR signaling cascade.
Collapse
Affiliation(s)
- Luciana K. Rosselli-Murai
- Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Luciana O. Almeida
- Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Chiara Zagni
- Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Pablo Galindo-Moreno
- Department of Oral Surgery and Implant Dentistry, School of Dentistry, University of Granada, Granada, Spain
| | - Miguel Padial-Molina
- Department of Oral Surgery and Implant Dentistry, School of Dentistry, University of Granada, Granada, Spain
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Sarah L. Volk
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Marcelo J. Murai
- The Division of Hematology and Oncology, University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan, United States of America
| | - Hector F. Rios
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Cristiane H. Squarize
- Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Rogerio M. Castilho
- Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
| |
Collapse
|
71
|
Doma E, Rupp C, Varga A, Kern F, Riegler B, Baccarini M. Skin tumorigenesis stimulated by Raf inhibitors relies upon Raf functions that are dependent and independent of ERK. Cancer Res 2013; 73:6926-37. [PMID: 24129679 DOI: 10.1158/0008-5472.can-13-0748] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RAF inhibitors achieve unprecedented but mainly transient clinical responses in patients with melanoma whose tumors harbor an activating BRAF mutation. One notable side-effect of RAF inhibitors is the stimulation of cutaneous skin tumors, arising in about 30% of patients receiving these drugs, which are thought to develop as a result of inhibitor-induced activation of wild-type Raf in occult precursor skin lesions. This effect raises the possibility that less manageable tumors might also arise in other epithelial tissues. Here we provide preclinical evidence supporting this disquieting hypothesis by showing that the RAF inhibitors PLX-4032 (vemurafenib) and GDC-0879 precipitate the development of cell-autonomous, Ras-driven tumors in skin and gastric epithelia. The magnitude of the effects correlated with the inhibitors' relative abilities to induce ERK activation. Epidermis-restricted ablation of either B-Raf or C-Raf prevented PLX-4032-induced ERK activation and tumorigenesis. In contrast, GDC-0879 induced ERK activation and tumorigenesis in B-Raf-deficient epidermis, whereas C-Raf ablation blocked GDC-0879-induced tumorigenesis (despite strong ERK activation) by preventing Rokα-mediated keratinocyte dedifferentiation. Thus, inhibitor-induced ERK activation did not require a specific Raf kinase. ERK activation was necessary, but not sufficient for Ras + Raf inhibitor-induced tumorigenesis, whereas C-Raf downregulation of Rokα was essential even in the face of sustained ERK signaling to prevent differentiation and promote tumorigenesis. Taken together, our findings suggest that combination therapies targeting ERK-dependent and -independent functions of Raf may be more efficient but also safer for cancer treatment.
Collapse
Affiliation(s)
- Eszter Doma
- Authors' Affiliation: Department of Microbiology, Immunobiology and Genetics, University of Vienna, Max F. Perutz Laboratories, Vienna, Austria
| | | | | | | | | | | |
Collapse
|
72
|
McDougall ARA, Hooper SB, Zahra VA, Cole TJ, Lo CY, Doran T, Wallace MJ. Trop2 regulates motility and lamellipodia formation in cultured fetal lung fibroblasts. Am J Physiol Lung Cell Mol Physiol 2013; 305:L508-21. [DOI: 10.1152/ajplung.00160.2012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Proliferation and migration of fibroblasts are vital for fetal lung development. However, the regulatory mechanisms are poorly understood. We have previously shown that TROP2 gene expression is closely associated with fetal lung cell proliferation in vivo and that TROP2 knockdown decreases proliferation of fetal lung fibroblasts in culture. We hypothesized that the Trop2 protein also regulates the morphology and motility of fetal lung fibroblasts. Fibroblasts isolated from fetal rat lungs (gestational age embryonic day 19) adopted a myofibroblast-like morphology in culture. Trop2 protein was localized to lamellipodia. TROP2 siRNA significantly decreased: TROP2 mRNA levels by 77%, the proportion of cells containing Trop2 protein by 70%, and cell proliferation by 50%. TROP2 siRNA also decreased the degree of motility as determined by the number of gridlines that cells moved across (2.2 ± 0.2 vs. 3.2 ± 0.2; P < 0.001). TROP2 knockdown altered cell morphology, causing a notable absence of lamellipodia and abnormal localization of components of the cell migration apparatus, and it reduced phosphorylated ERK1 and ERK2 levels. In contrast, TROP2 overexpression significantly increased: TROP2 mRNA levels by 40-fold, cell proliferation by 40%, the proportion of cells that were motile by 20%, and the number of gridlines that cells moved across (2.1 ± 0.2 vs. 1.6 ± 0.1; P < 0.001). Our data suggest that Trop2 regulates cell proliferation and motility and that it does so by regulating the ERK pathway and several critical components of the cell migration apparatus.
Collapse
Affiliation(s)
- Annie R. A. McDougall
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia
- The Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Stuart B. Hooper
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia
- Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Valerie A. Zahra
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia
| | - Timothy J. Cole
- The Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Camden Y. Lo
- Monash Micro Imaging, Monash University, Clayton, Victoria, Australia; and
| | - Timothy Doran
- Lifestock Industries, Australia's Commonwealth Scientific and Industrial Research Organisation, Geelong, Victoria, Australia
| | - Megan J. Wallace
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia
- Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| |
Collapse
|
73
|
EGFR-ras-raf signaling in epidermal stem cells: roles in hair follicle development, regeneration, tissue remodeling and epidermal cancers. Int J Mol Sci 2013; 14:19361-84. [PMID: 24071938 PMCID: PMC3821561 DOI: 10.3390/ijms141019361] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/12/2013] [Accepted: 09/17/2013] [Indexed: 12/19/2022] Open
Abstract
The mammalian skin is the largest organ of the body and its outermost layer, the epidermis, undergoes dynamic lifetime renewal through the activity of somatic stem cell populations. The EGFR-Ras-Raf pathway has a well-described role in skin development and tumor formation. While research mainly focuses on its role in cutaneous tumor initiation and maintenance, much less is known about Ras signaling in the epidermal stem cells, which are the main targets of skin carcinogenesis. In this review, we briefly discuss the properties of the epidermal stem cells and review the role of EGFR-Ras-Raf signaling in keratinocyte stem cells during homeostatic and pathological conditions.
Collapse
|
74
|
Morgan-Fisher M, Couchman JR, Yoneda A. Phosphorylation and mRNA splicing of collapsin response mediator protein-2 determine inhibition of rho-associated protein kinase (ROCK) II function in carcinoma cell migration and invasion. J Biol Chem 2013; 288:31229-40. [PMID: 24036111 DOI: 10.1074/jbc.m113.505602] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Rho-associated protein kinases (ROCK I and II) are central regulators of important cellular processes such as migration and invasion downstream of the GTP-Rho. Recently, we reported collapsin response mediator protein (CRMP)-2 as an endogenous ROCK II inhibitor. To reveal how the CRMP-2-ROCK II interaction is controlled, we further mapped the ROCK II interaction site of CRMP-2 and examined whether phosphorylation states of CRMP-2 affected the interaction. Here, we show that an N-terminal fragment of the long CRMP-2 splice variant (CRMP-2L) alone binds ROCK II and inhibits colon carcinoma cell migration and invasion. Furthermore, the interaction of CRMP-2 and ROCK II is partially regulated by glycogen synthase kinase (GSK)-3 phosphorylation of CRMP-2, downstream of PI3K. Inhibition of PI3K reduced interaction of CRMP-2 with ROCK II, an effect rescued by simultaneous inhibition of GSK3. Inhibition of PI3K also reduced colocalization of ROCK II and CRMP-2 at the cell periphery in human breast carcinoma cells. Mimicking GSK3 phosphorylation of CRMP-2 significantly reduced CRMP-2 binding of recombinant full-length and catalytic domain of ROCK II. These data implicate GSK3 in the regulation of ROCK II-CRMP-2 interactions. Using phosphorylation-mimetic and -resistant CRMP-2L constructs, it was revealed that phosphorylation of CRMP-2L negatively regulates its inhibitory function in ROCK-dependent haptotactic cell migration, as well as invasion of human colon carcinoma cells. Collectively, the presented data show that CRMP-2-dependent regulation of ROCK II activity is mediated through interaction of the CRMP-2L N terminus with the ROCK II catalytic domain as well as by GSK3-dependent phosphorylation of CRMP-2.
Collapse
Affiliation(s)
- Marie Morgan-Fisher
- From the Department of Biomedical Sciences, Faculty of Health and Medical Sciences, and Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, Copenhagen N, 2200, Denmark and
| | | | | |
Collapse
|
75
|
IAPs on the move: role of inhibitors of apoptosis proteins in cell migration. Cell Death Dis 2013; 4:e784. [PMID: 24008728 PMCID: PMC3789170 DOI: 10.1038/cddis.2013.311] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 07/09/2013] [Indexed: 01/06/2023]
Abstract
Inhibitors of Apoptosis Proteins (IAPs) are a class of highly conserved proteins predominantly known for the regulation of caspases and immune signaling. However, recent evidence suggests a crucial role for these molecules in the regulation of tumor cell shape and migration by controlling MAPK, NF-κB and Rho GTPases. IAPs directly control Rho GTPases, thus regulating cell shape and migration. For instance, XIAP and cIAP1 function as the direct E3 ubiquitin ligases of Rac1 and target it for proteasomal degradation. IAPs are differentially expressed in tumor cells and have been targeted by several cancer therapeutic drugs that are currently in clinical trials. Here, we summarize the current knowledge on the role of IAPs in the regulation of cell migration and discuss the possible implications of these observations in regulating tumor cell metastases.
Collapse
|
76
|
Hwang YC, Yang CH, Lin CH, Ch'ang HJ, Chang VHS, Yu WCY. Destabilization of KLF10, a tumor suppressor, relies on thr93 phosphorylation and isomerase association. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:3035-3045. [PMID: 23994618 DOI: 10.1016/j.bbamcr.2013.08.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 08/08/2013] [Accepted: 08/12/2013] [Indexed: 12/24/2022]
Abstract
KLF10 is now classified as a member of the Krüppel-like transcription factor family and acts as a tumor suppressor. Although KLF10 is originally named as TGF-β-inducible early gene-1 and mimicking the anti-proliferative effect of TGF-β in various carcinoma cells, the transcriptional upregulatory function of KLF10 has been described for a variety of cytokines and in many diseases. Through in vivo and in vitro phosphorylation assays, we identified that KLF10 is a phosphorylated protein in cells. Using yeast-two hybrid screening and site direct mutagenesis, we also identified PIN1 as a novel KLF10 associated protein. PIN1 is a peptidyl-prolyl isomerase enzyme belonging to the parvulin family, which specifically recognizes phosphorylated Ser/Thr-Pro containing substrates. Through protein-protein interaction assays, we showed that the Pro-directed Ser/Thr-Pro motif at Thr-93 in the KLF10 N-terminal region is essential for the interaction between KLF10 and PIN1. More importantly, PIN1 interacts with KLF10 in a phosphorylation-dependent manner and this interaction promotes KLF10 protein degradation in cells. Therefore, KLF10 shows shorter protein stability compared with mutant KLF10 that lacks PIN1 binding ability after cycloheximide treatments. The reversely correlated expression profile between KLF10 and PIN1 as observed in cell lines was also shown in clinic pancreatic cancer specimen. Using in vitro kinase assays and depletion assays, we were able to show that RAF-1 phosphorylates the Thr-93 of KLF10 and affects the KLF10 expression level in cells. Thus these findings as a whole indicate that RAF-1 phosphorylation and PIN1 isomerization together regulate KLF10 stability and further affect the role of KLF10 in tumor progression.
Collapse
Affiliation(s)
- Yu-Chyi Hwang
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
| | - Chien-Hui Yang
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
| | - Ching-Hui Lin
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
| | - Hui-Ju Ch'ang
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
| | - Vincent H S Chang
- Program for Translation Medicine, College of Medical Science and Technology, Taipei Medical University, Taiwan.
| | - Winston C Y Yu
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan; College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.
| |
Collapse
|
77
|
Schofield AV, Bernard O. Rho-associated coiled-coil kinase (ROCK) signaling and disease. Crit Rev Biochem Mol Biol 2013; 48:301-16. [PMID: 23601011 DOI: 10.3109/10409238.2013.786671] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The small Rho GTPase family of proteins, encompassing the three major G-protein classes Rho, Rac and cell division control protein 42, are key mitogenic signaling molecules that regulate multiple cancer-associated cellular phenotypes including cell proliferation and motility. These proteins are known for their role in the regulation of actin cytoskeletal dynamics, which is achieved through modulating the activity of their downstream effector molecules. The Rho-associated coiled-coil kinase 1 and 2 (ROCK1 and ROCK2) proteins were the first discovered Rho effectors that were primarily established as players in RhoA-mediated stress fiber formation and focal adhesion assembly. It has since been discovered that the ROCK kinases actively phosphorylate a large cohort of actin-binding proteins and intermediate filament proteins to modulate their functions. It is well established that global cellular morphology, as modulated by the three cytoskeletal networks: actin filaments, intermediate filaments and microtubules, is regulated by a variety of accessory proteins whose activities are dependent on their phosphorylation by the Rho-kinases. As a consequence, they regulate many key cellular functions associated with malignancy, including cell proliferation, motility and viability. In this current review, we focus on the role of the ROCK-signaling pathways in disease including cancer.
Collapse
Affiliation(s)
- Alice V Schofield
- St Vincent's Institute of Medical Research, Cytoskeleton and Cancer Unit and Department of Medicine, St Vincent's Hospital, University of Melbourne, Victoria 3065, Australia
| | | |
Collapse
|
78
|
Isoir M, Roque T, Squiban C, Milliat F, Mondon P, Mas-Chamberlin C, Benderitter M, Guipaud O, Tamarat R. Protective Effect of Geranylgeranylacetone against Radiation-Induced Delayed Effects on Human Keratinocytes. Radiat Res 2013; 179:232-242. [DOI: 10.1667/rr2717.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
|
79
|
Yotova I, Quan P, Gaba A, Leditznig N, Pateisky P, Kurz C, Tschugguel W. Raf-1 levels determine the migration rate of primary endometrial stromal cells of patients with endometriosis. J Cell Mol Med 2013; 16:2127-39. [PMID: 22225925 PMCID: PMC3822983 DOI: 10.1111/j.1582-4934.2011.01520.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Endometriosis is a disease characterized by the localization of endometrial tissue outside the uterine cavity. The differences observed in migration of human endometrial stromal cells (hESC) obtained from patients with endometriosis versus healthy controls were proposed to correlate with the abnormal activation of Raf-1/ROCKII signalling pathway. To evaluate the mechanism by which Raf-1 regulates cytoskeleton reorganization and motility, we used primary eutopic (Eu-, n = 16) and ectopic (Ec-, n = 8; isolated from ovarian cysts) hESC of patients with endometriosis and endometriosis-free controls (Co-hESC, n = 14). Raf-1 siRNA knockdown in Co- and Eu-hESC resulted in contraction and decreased migration versus siRNA controls. This phenotype was reversed following the re-expression of Raf-1 in these cells. Lowest Raf-1 levels in Ec-hESC were associated with hyperactivated ROCKII and ezrin/radixin/moesin (E/R/M), impaired migration and a contracted phenotype similar to Raf-1 knockdown in Co- and Eu-hESC. We further show that the mechanism by which Raf-1 mediates migration in hESC includes direct myosin light chain phosphatase (MYPT1) phosphorylation and regulation of the levels of E/R/M, paxillin, MYPT1 and myosin light chain (MLC) phosphorylation indirectly via the hyperactivation of ROCKII kinase. Furthermore, we suggest that in contrast to Co-and Eu-hESC, where the cellular Raf-1 levels regulate the rate of migration, the low cellular Raf-1 content in Ec-hESC, might ensure their restricted migration by preserving the contracted cellular phenotype. In conclusion, our findings suggest that cellular levels of Raf-1 adjust the threshold of hESC migration in endometriosis.
Collapse
Affiliation(s)
- Iveta Yotova
- Department of Obstetrics and Gynecology, Medical University of Vienna, Vienna, Austria
| | | | | | | | | | | | | |
Collapse
|
80
|
Abstract
Cancer-associated changes in cellular behavior, such as modified cell-cell contact, increased migratory potential, and generation of cellular force, all require alteration of the cytoskeleton. Two homologous mammalian serine/threonine kinases, Rho-associated protein kinases (ROCK I and II), are key regulators of the actin cytoskeleton acting downstream of the small GTPase Rho. ROCK is associated with cancer progression, and ROCK protein expression is elevated in several types of cancer. ROCKs exist in a closed, inactive conformation under quiescent conditions, which is changed to an open, active conformation by the direct binding of guanosine triphosphate (GTP)–loaded Rho. In recent years, a number of ROCK isoform-specific binding partners have been found to modulate the kinase activity through direct interactions with the catalytic domain or via altered cellular localization of the kinases. Thus, these findings demonstrate additional modes to regulate ROCK activity. This review describes the molecular mechanisms of ROCK activity regulation in cancer, with emphasis on ROCK isoform-specific regulation and interaction partners, and discusses the potential of ROCKs as therapeutic targets in cancer.
Collapse
Affiliation(s)
- Marie Morgan-Fisher
- Department of Biomedical Sciences, The Faculty of Health and Medical Sciences, and Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Denmark
| | | | | |
Collapse
|
81
|
Abstract
Ran-binding protein M (RanBPM) is a nucleocytoplasmic protein of yet unknown function. We have previously shown that RanBPM inhibits expression of the anti-apoptotic factor Bcl-2 and promotes apoptosis induced by DNA damage. Here we show that the effects of RanBPM on Bcl-2 expression occur through a regulation of the ERK signaling pathway. Transient and stable down-regulation of RanBPM stimulated ERK phosphorylation, leading to Bcl-2 up-regulation, while re-expression of RanBPM reversed these effects. RanBPM was found to inhibit MEK and ERK activation induced by ectopic expression of active RasV12. Activation of ERK by active c-Raf was also prevented by RanBPM. Expression of RanBPM correlated with a marked decrease in the protein levels of ectopically expressed active c-Raf and also affected the expression of endogenous c-Raf. RanBPM formed a complex with both active c-Raf, consisting of the C-terminal kinase domain, and endogenous c-Raf in mammalian cells. In addition, RanBPM was found to decrease the binding of Hsp90 to c-Raf. Finally, we show that loss of RanBPM expression confers increased cell proliferation and cell migration properties to HEK293 cells. Altogether, these findings establish RanBPM as a novel inhibitor of the ERK pathway through an interaction with the c-Raf complex and a regulation of c-Raf stability, and provide evidence that RanBPM loss of expression results in constitutive activation of the ERK pathway and promotes cellular events leading to cellular transformation and tumorigenesis.
Collapse
Affiliation(s)
| | - Caroline Schild-Poulter
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
- * E-mail:
| |
Collapse
|
82
|
Coló GP, Hernández-Varas P, Lock J, Bartolomé RA, Arellano-Sánchez N, Strömblad S, Teixidó J. Focal adhesion disassembly is regulated by a RIAM to MEK-1 pathway. J Cell Sci 2012; 125:5338-52. [PMID: 22946047 DOI: 10.1242/jcs.105270] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cell migration and invasion require regulated turnover of integrin-dependent adhesion complexes. Rap1-GTP-interacting adaptor molecule (RIAM) is an adaptor protein that mediates talin recruitment to the cell membrane, and whose depletion leads to defective melanoma cell migration and invasion. In this study, we investigated the potential involvement of RIAM in focal adhesion (FA) dynamics. RIAM-depleted melanoma and breast carcinoma cells displayed an increased number, size and stability of FAs, which accumulated centrally at the ventral cell surface, a phenotype caused by defective FA disassembly. Impairment in FA disassembly resulting from RIAM knockdown correlated with deficient integrin-dependent mitogen-activated protein kinase kinase (MEK)-Erk1/2 activation and, importantly, overexpression of constitutively active MEK resulted in rescue of FA disassembly and recovery of cell invasion. Furthermore, RIAM-promoted Ras homologue gene family, member A (RhoA) activation following integrin engagement was needed for subsequent Erk1/2 activation. In addition, RhoA overexpression partially rescued the FA phenotype in RIAM-depleted cells, also suggesting a functional role for RhoA downstream of RIAM, but upstream of Erk1/2. RIAM knockdown also led to enhanced phosphorylation of paxillin Tyr118 and Tyr31. However, expression of phosphomimetic and nonphosphorylatable mutants at these paxillin residues indicated that paxillin hyperphosphorylation is a subsequent consequence of the blockade of FA disassembly, but does not cause the FA phenotype. RIAM depletion also weakened the association between FA proteins, suggesting that it has important adaptor roles in the correct assembly of adhesion complexes. Our data suggest that integrin-triggered, RIAM-dependent MEK activation represents a key feedback event required for efficient FA disassembly, which could help explain the role of RIAM in cell migration and invasion.
Collapse
Affiliation(s)
- Georgina P Coló
- Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), 28040 Madrid, Spain
| | | | | | | | | | | | | |
Collapse
|
83
|
Increased cell growth due to a new lipase-GEF (Phospholipase D2) fastly acting on Ras. Cell Signal 2012; 25:198-205. [PMID: 22960035 DOI: 10.1016/j.cellsig.2012.08.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 08/27/2012] [Indexed: 11/20/2022]
Abstract
We report the novel finding that Phospholipase D2 (PLD2), through its PX and PH domains, binds specifically to Ras and catalyzes the GDP/GTP exchange (i.e., is a GEF), with potency comparable to Ras-GRF-1, a known Ras-GEF. Cells overexpressing PLD2-GEF inactive mutants (F129Y and R172C/L173A) fail to stimulate cell proliferation compared to the wild type-expressing cells. The GEF effect on Ras follows a faster kinetics than other GTPase substrates (such as Rac2 or Rac1) and is a better substrate, too. The GEF action is due to PLD2 (protein) itself, independent of the lipase product PA. PA can still have a fine-tuning regulatory effect on Ras-GTP depending upon its cellular concentration. Rapidly growing human breast cancer cells MDA-MB 231 (but not the slow growing MCF7 counterpart) have high levels of endogenous PLD2-GEF which correlates with high Ras activation. The PLD2-"GEF" activity is even higher than the classical "lipase" activity and is abrogated with GEF single point mutants, particularly F129Y, and concomitantly with a slow rate of cell growth. This can be crucial to cancer biology in that not only Ras mutations explain abnormal growth, but the existence of a new GEF for Ras: a GEF molecule that happens to be a phospholipase.
Collapse
|
84
|
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: 185] [Impact Index Per Article: 15.4] [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.
Collapse
|
85
|
Abstract
Ras-driven tumorigenesis is assumed to depend on Raf for ERK activation and proliferation; yet, an in vivo requirement for Raf as MEK/ERK activator in this setting has not been demonstrated to date. Here, we show that epidermis-restricted B-Raf ablation restrains the onset and stops the progression of established Ras-driven tumors by limiting MEK/ERK activation and proliferation. Concomitant elimination of B-Raf and Raf-1 enforces the abrupt regression of established tumors owing to the decrease in ERK activation and proliferation caused by B-Raf ablation combined with the ERK-independent increase in Rho-dependent kinase (Rok) signaling and differentiation triggered by Raf-1 inactivation. Thus, B-Raf and Raf-1 have non-redundant functions in Ras-driven tumorigenesis. Of note, Raf kinase inhibitors achieve impressive results in melanomas harboring oncogenic BRAF, but are ineffective against Ras-driven tumors; moreover, therapy-related skin tumors driven by a paradox ERK activation as well as primary and acquired resistance have been reported. Our results suggest that therapies targeting both Raf kinase-dependent and -independent pathways may be effective against a broader range of malignancies and reduce the risks of adverse effects and/or resistance.
Collapse
|
86
|
Faure E, Garrouste F, Parat F, Monferran S, Leloup L, Pommier G, Kovacic H, Lehmann M. P2Y2 receptor inhibits EGF-induced MAPK pathway to stabilise keratinocyte hemidesmosomes. J Cell Sci 2012; 125:4264-77. [PMID: 22718344 DOI: 10.1242/jcs.097600] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
α6β4 integrin is the main component of hemidesmosomes (HD) that stably anchor the epithelium to the underlying basement membrane. Epithelial cell migration requires HD remodelling, which can be promoted by epidermal growth factor (EGF). We previously showed that extracellular nucleotides inhibit growth factor-induced keratinocyte migration. Here, we investigate the effect of extracellular nucleotides on α6β4 integrin localisation in HD during EGF-induced cell migration. Using a combination of pharmacological inhibition and gene silencing approaches, we found that UTP activates the P2Y2 purinergic receptor and Gαq protein to inhibit EGF/ERK1/2-induced cell migration in keratinocytes. Using a keratinocyte cell line expressing an inducible form of the Raf kinase, we show that UTP inhibits the EGF-induced ERK1/2 pathway activation downstream of Raf. Moreover, we established that ERK1/2 activation by EGF leads to the mobilisation of α6β4 integrin from HD. Importantly, activation of P2Y2R and Gαq by UTP promotes HD formation and protects these structures from EGF-triggered dissolution as revealed by confocal analysis of the distribution of α6β4 integrin, plectin, BPAG1, BPAG2 and CD151 in keratinocytes. Finally, we demonstrated that the activation of p90RSK, downstream of ERK1/2, is sufficient to promote EGF-mediated HD dismantling and that UTP does not stabilise HD in cells expressing an activated form of p90RSK. Our data underline an unexpected role of P2Y2R and Gαq in the inhibition of the ERK1/2 signalling pathway and in the modulation of hemidesmosome dynamics and keratinocyte migration.
Collapse
Affiliation(s)
- Emilie Faure
- Aix-Marseille Université, INSERM UMR 911, Centre de Recherche en Oncologie Biologique et en Oncopharmacologie, Marseille 13005, France
| | | | | | | | | | | | | | | |
Collapse
|
87
|
Abstract
Several observations have led us to a new hypothesis for cancer mechanism. First, that cancer appears only on those multicellular organisms with complicated wound-healing capacities. Second, that wounds considered as risk factors can be identified in all cancers in clinics. And finally, that oncogene activation appears not only in cancer, but also in normal physiology and noncancer pathology processes. Our proposed hypothesis is that cancer is a natural wound healing-related process, which includes oncogene activations, cytokine secretions, stem cell recruitment differentiation, and tissue remodeling. Wounds activate oncogenes of some cells and the latter secrete cytokines to recruit stem cells to heal the wounds. However, if the cause of the wound or if the wound persists, such as under the persistent UV and carcinogen exposures, the continuous wound healing process will lead to a clinical cancer mass. There is no system in nature to stop or reverse the wound healing process in the middle stage when the wound exists. The outcome of the cancer mechanism is either healing the wound or exhausting the whole system (death). The logic of this cancer mechanism is consistent with the rationales of the other physiological metabolisms in the body-for survival. This hypothesis helps to understand many cancer mysteries derived from the mutation theory, such as why cancer only exists in a small proportion of multicellular organisms, although they are all under potential mutation risks during DNA replications. The hypothesis can be used to interpret and guide cancer prevention, recurrence, metastasis, in vitro and in vivo studies, and personalized treatments.
Collapse
Affiliation(s)
- Xiaolong Meng
- Breast Medical Oncology Department, MD Anderson Cancer Center, 1155 Hermann Pressler Dr., Houston, TX 77030 USA
| | - Jie Zhong
- Neurosurgery Department, MD Anderson Cancer Center, 1400 Holcombe Blvd., Houston, TX 77030 USA
| | - Shuying Liu
- Breast Medical Oncology Department, MD Anderson Cancer Center, 1155 Hermann Pressler Dr., Houston, TX 77030 USA
| | - Mollianne Murray
- Systems Biology Department, MD Anderson Cancer Center, 7435 Fannin St., Houston, TX 77054 USA
| | - Ana M. Gonzalez-Angulo
- Breast Medical Oncology Department, MD Anderson Cancer Center, 1155 Hermann Pressler Dr., Houston, TX 77030 USA
| |
Collapse
|
88
|
Baljuls A, Beck M, Oenel A, Robubi A, Kroschewski R, Hekman M, Rudel T, Rapp UR. The tumor suppressor DiRas3 forms a complex with H-Ras and C-RAF proteins and regulates localization, dimerization, and kinase activity of C-RAF. J Biol Chem 2012; 287:23128-40. [PMID: 22605333 DOI: 10.1074/jbc.m112.343780] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The maternally imprinted Ras-related tumor suppressor gene DiRas3 is lost or down-regulated in more than 60% of ovarian and breast cancers. The anti-tumorigenic effect of DiRas3 is achieved through several mechanisms, including inhibition of cell proliferation, motility, and invasion, as well as induction of apoptosis and autophagy. Re-expression of DiRas3 in cancer cells interferes with the signaling through Ras/MAPK and PI3K. Despite intensive research, the mode of interference of DiRas3 with the Ras/RAF/MEK/ERK signal transduction is still a matter of speculation. In this study, we show that DiRas3 associates with the H-Ras oncogene and that activation of H-Ras enforces this interaction. Furthermore, while associated with DiRas3, H-Ras is able to bind to its effector protein C-RAF. The resulting multimeric complex consisting of DiRas3, C-RAF, and active H-Ras is more stable than the two protein complexes H-Ras·C-RAF or H-Ras·DiRas3, respectively. The consequence of this complex formation is a DiRas3-mediated recruitment and anchorage of C-RAF to components of the membrane skeleton, suppression of C-RAF/B-RAF heterodimerization, and inhibition of C-RAF kinase activity.
Collapse
Affiliation(s)
- Angela Baljuls
- Theodor Boveri Institute of Bioscience, Department of Microbiology, University of Wuerzburg, 97074 Wuerzburg, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
89
|
Hoogwater FJH, Steller EJA, Westendorp BF, Borel Rinkes IHM, Kranenburg O. CD95 signaling in colorectal cancer. Biochim Biophys Acta Rev Cancer 2012; 1826:189-98. [PMID: 22498253 DOI: 10.1016/j.bbcan.2012.03.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 03/09/2012] [Accepted: 03/10/2012] [Indexed: 02/07/2023]
Abstract
CD95 and its ligand (CD95L) are widely expressed in colorectal tumors, but their role in shaping tumor behavior is unclear. CD95 activation on tumor cells can lead to apoptosis, while CD95L attracts neutrophils, suggesting a function in tumor suppression. However, CD95 can also promote tumorigenesis, at least in part by activating non-apoptotic signaling pathways that stimulate tumor cell proliferation, invasion and survival. In addition, CD95 signaling in stromal cells and tumor-infiltrating inflammatory cells has to be taken into account when addressing the function of CD95 and its ligand in colorectal tumor biology. We present a model in which the tumor-suppressing and tumor-promoting activities of CD95/CD95L together determine colorectal tumor behavior. We also discuss how these multiple activities are changing our view of CD95 and CD95L as potential therapeutic targets in the treatment of colorectal cancer. We conclude that locking CD95 in apoptosis-mode may be a more promising anti-cancer strategy than simply inhibiting or stimulating CD95.
Collapse
|
90
|
Hensel N, Ratzka A, Brinkmann H, Klimaschewski L, Grothe C, Claus P. Analysis of the fibroblast growth factor system reveals alterations in a mouse model of spinal muscular atrophy. PLoS One 2012; 7:e31202. [PMID: 22348054 PMCID: PMC3278439 DOI: 10.1371/journal.pone.0031202] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 01/04/2012] [Indexed: 12/02/2022] Open
Abstract
The monogenetic disease Spinal Muscular Atrophy (SMA) is characterized by a progressive loss of motoneurons leading to muscle weakness and atrophy due to severe reduction of the Survival of Motoneuron (SMN) protein. Several models of SMA show deficits in neurite outgrowth and maintenance of neuromuscular junction (NMJ) structure. Survival of motoneurons, axonal outgrowth and formation of NMJ is controlled by neurotrophic factors such as the Fibroblast Growth Factor (FGF) system. Besides their classical role as extracellular ligands, some FGFs exert also intracellular functions controlling neuronal differentiation. We have previously shown that intracellular FGF-2 binds to SMN and regulates the number of a subtype of nuclear bodies which are reduced in SMA patients. In the light of these findings, we systematically analyzed the FGF-system comprising five canonical receptors and 22 ligands in a severe mouse model of SMA. In this study, we demonstrate widespread alterations of the FGF-system in both muscle and spinal cord. Importantly, FGF-receptor 1 is upregulated in spinal cord at a pre-symptomatic stage as well as in a mouse motoneuron-like cell-line NSC34 based model of SMA. Consistent with that, phosphorylations of FGFR-downstream targets Akt and ERK are increased. Moreover, ERK hyper-phosphorylation is functionally linked to FGFR-1 as revealed by receptor inhibition experiments. Our study shows that the FGF system is dysregulated at an early stage in SMA and may contribute to the SMA pathogenesis.
Collapse
Affiliation(s)
- Niko Hensel
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Andreas Ratzka
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Hella Brinkmann
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Lars Klimaschewski
- Division of Neuroanatomy, Innsbruck Medical University, Innsbruck, Austria
| | - Claudia Grothe
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
| | - Peter Claus
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
- * E-mail:
| |
Collapse
|
91
|
Gruber HE, Somayaji S, Riley F, Hoelscher GL, Norton HJ, Ingram J, Hanley EN. Human adipose-derived mesenchymal stem cells: serial passaging, doubling time and cell senescence. Biotech Histochem 2012; 87:303-11. [DOI: 10.3109/10520295.2011.649785] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
|
92
|
Davis R, Pillai S, Lawrence N, Sebti S, Chellappan SP. TNF-α-mediated proliferation of vascular smooth muscle cells involves Raf-1-mediated inactivation of Rb and transcription of E2F1-regulated genes. Cell Cycle 2012; 11:109-18. [PMID: 22185776 DOI: 10.4161/cc.11.1.18473] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Atherosclerosis is characterized by hyperplastic neointima and an inflammatory response with cytokines such as TNFα. TNFα is a pleiotropic cytokine that mediates inflammatory, proliferative, cytostatic and cytotoxic effects in a variety of cell types, including endothelial cells and vascular smooth muscle cells (VSMCs). Interestingly, TNFα has been shown to play two very opposing roles in these cell types; it inhibits proliferation and induces apoptosis in endothelial cells, while it enhances the proliferation and migration of VSMCs. Here we show that TNFα is capable of stimulating proliferation of rat VSMCs as well as human VSMCs in a Raf-1/MAP K-dependent manner. TNFα could increase the expression of E2F-regulated proliferative cdc6, Thymidylate synthase (TS) and cdc25A genes in Aortic smooth muscle cells (AoSMC), as seen by real time PCR assays. There is an activation of the stress-induced kinase, JNK1, in VSMCs upon TNFα stimulation. TNFα was capable of inducing binding of the Raf-1 kinase to Rb, and treatment with the Rb-Raf-1 inhibitor, RRD-251, could prevent TNFα-induced S-phase entry in AoSMCs. In addition, inhibition of Raf-1 or Src kinases using pharmacologic inhibitors could also prevent S-phase entry, while inhibition of JNK was not as effective. These results suggest that inhibiting the Rb-Raf-1 interaction is a potential avenue to prevent VSMC proliferation associated with atherosclerosis.
Collapse
Affiliation(s)
- Rebecca Davis
- H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | | | | | | | | |
Collapse
|
93
|
Wimmer R, Cseh B, Maier B, Scherrer K, Baccarini M. Angiogenic sprouting requires the fine tuning of endothelial cell cohesion by the Raf-1/Rok-α complex. Dev Cell 2011; 22:158-71. [PMID: 22209329 PMCID: PMC3268451 DOI: 10.1016/j.devcel.2011.11.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 11/09/2011] [Accepted: 11/28/2011] [Indexed: 11/30/2022]
Abstract
Sprouting angiogenesis, crucial for the development of new blood vessels, is a prime example of collective migration in which endothelial cells migrate as a group joined via cadherin-containing adherens junctions (AJ). The actomyosin apparatus is connected to AJ and generates contractile forces, which, depending on their strength and duration, increase or decrease cell cohesion. Thus, appropriate spatiotemporal control of junctional myosin is critical, but the mechanisms underlying it are incompletely understood. We show that Raf-1 is an essential component of this regulatory network and that its ablation impairs endothelial cell cohesion, sprouting, and tumor-induced angiogenesis. Mechanistically, Raf-1 is recruited to VE-cadherin complexes by a mechanism involving the small G protein Rap1 and is required to bring the Rho effector Rok-α to nascent AJs. This Raf-1-mediated fine tuning of Rok-α signaling allows the activation of junctional myosin and the timely maturation of AJ essential for maintaining cell cohesion during sprouting angiogenesis.
Collapse
Affiliation(s)
- Reiner Wimmer
- Department of Microbiology and Immunobiology, University of Vienna, Max F. Perutz Laboratories, Doktor-Bohr-Gasse 9, 1030 Vienna, Austria
| | - Botond Cseh
- Department of Microbiology and Immunobiology, University of Vienna, Max F. Perutz Laboratories, Doktor-Bohr-Gasse 9, 1030 Vienna, Austria
| | - Barbara Maier
- Department of Microbiology and Immunobiology, University of Vienna, Max F. Perutz Laboratories, Doktor-Bohr-Gasse 9, 1030 Vienna, Austria
| | - Karina Scherrer
- Department of Microbiology and Immunobiology, University of Vienna, Max F. Perutz Laboratories, Doktor-Bohr-Gasse 9, 1030 Vienna, Austria
| | - Manuela Baccarini
- Department of Microbiology and Immunobiology, University of Vienna, Max F. Perutz Laboratories, Doktor-Bohr-Gasse 9, 1030 Vienna, Austria
- Corresponding author
| |
Collapse
|
94
|
Oberoi TK, Dogan T, Hocking JC, Scholz RP, Mooz J, Anderson CL, Karreman C, Meyer zu Heringdorf D, Schmidt G, Ruonala M, Namikawa K, Harms GS, Carpy A, Macek B, Köster RW, Rajalingam K. IAPs regulate the plasticity of cell migration by directly targeting Rac1 for degradation. EMBO J 2011; 31:14-28. [PMID: 22117219 DOI: 10.1038/emboj.2011.423] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 10/28/2011] [Indexed: 11/09/2022] Open
Abstract
Inhibitors of apoptosis proteins (IAPs) are a highly conserved class of multifunctional proteins. Rac1 is a well-studied Rho GTPase that controls numerous basic cellular processes. While the regulation of nucleotide binding to Rac1 is well understood, the molecular mechanisms controlling Rac1 degradation are not known. Here, we demonstrate X-linked IAP (XIAP) and cellular IAP1 (c-IAP1) directly bind to Rac1 in a nucleotide-independent manner to promote its polyubiquitination at Lys147 and proteasomal degradation. These IAPs are also required for degradation of Rac1 upon CNF1 toxin treatment or RhoGDI depletion. Consistently, downregulation of XIAP or c-IAP1 by various strategies led to an increase in Rac1 protein levels in primary and tumour cells, leading to an elongated morphology and enhanced cell migration. Further, XIAP counteracts Rac1-dependent cellular polarization in the developing zebrafish hindbrain and promotes the delamination of neurons from the normal tissue architecture. These observations unveil an evolutionarily conserved role of IAPs in controlling Rac1 stability thereby regulating the plasticity of cell migration and morphogenesis.
Collapse
Affiliation(s)
- Tripat Kaur Oberoi
- Emmy Noether Group of the DFG, Institute of Biochemistry II, Goethe University Medical School, Frankfurt, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
95
|
The secret life of kinases: functions beyond catalysis. Cell Commun Signal 2011; 9:23. [PMID: 22035226 PMCID: PMC3215182 DOI: 10.1186/1478-811x-9-23] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 10/28/2011] [Indexed: 02/07/2023] Open
Abstract
Protein phosphorylation participates in the regulation of all fundamental biological processes, and protein kinases have been intensively studied. However, while the focus was on catalytic activities, accumulating evidence suggests that non-catalytic properties of protein kinases are essential, and in some cases even sufficient for their functions. These non-catalytic functions include the scaffolding of protein complexes, the competition for protein interactions, allosteric effects on other enzymes, subcellular targeting, and DNA binding. This rich repertoire often is used to coordinate phosphorylation events and enhance the specificity of substrate phosphorylation, but also can adopt functions that do not rely on kinase activity. Here, we discuss such kinase independent functions of protein and lipid kinases focussing on kinases that play a role in the regulation of cell proliferation, differentiation, apoptosis, and motility.
Collapse
|
96
|
Alejandro EU, Lim GE, Mehran AE, Hu X, Taghizadeh F, Pelipeychenko D, Baccarini M, Johnson JD. Pancreatic β-cell Raf-1 is required for glucose tolerance, insulin secretion, and insulin 2 transcription. FASEB J 2011; 25:3884-95. [PMID: 21817126 DOI: 10.1096/fj.10-180349] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Regulation of glucose homeostasis by insulin depends on pancreatic β-cell growth, survival, and function. Raf-1 kinase is a major downstream target of several growth factors that promote proliferation and survival of many cell types, including the pancreatic β cells. We have previously reported that insulin protects β cells from apoptosis and promotes proliferation by activating Raf-1 signaling in cultured human islets, mouse islets, and MIN6 cells. As Raf-1 activity is critical for basal apoptosis and insulin secretion in vitro, we hypothesized that Raf-1 may play an important role in glucose homeostasis in vivo. To test this hypothesis, we utilized the Cre-loxP recombination system to obtain a pancreatic β-cell-specific ablation of Raf-1 kinase gene (RIPCre(+/+):Raf-1(flox/flox)) and a complete set of littermate controls (RIPCre(+/+):Raf-1(wt/wt)). RIPCre(+/+):Raf-1(flox/flox) mice were viable, and no effects on weight gain were observed. RIPCre(+/+):Raf-1(flox/flox) mice had increased fasting blood glucose levels and impaired glucose tolerance but normal insulin tolerance compared to littermate controls. Insulin secretion in vivo and in isolated islets was markedly impaired, but there was no apparent effect on the exocytosis machinery. However, islet insulin protein and insulin 2 mRNA, but not insulin 1 mRNA, were dramatically reduced in Raf-1-knockout mice. Analysis of insulin 2 knockout mice demonstrated that this reduction in mRNA was sufficient to impair in vivo insulin secretion. Our data further indicate that Raf-1 specifically and acutely regulates insulin 2 mRNA via negative action on Foxo1, which has been shown to selectively control the insulin 2 gene. This work provides the first direct evidence that Raf-1 signaling is essential for the regulation of basal insulin transcription and the supply of releasable insulin in vivo.
Collapse
Affiliation(s)
- Emilyn U Alejandro
- Laboratory of Molecular Signalling in Diabetes, Diabetes Research Group, Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | | | | | | | | | | | | | | |
Collapse
|
97
|
Vallenius T, Vaahtomeri K, Kovac B, Osiceanu AM, Viljanen M, Mäkelä TP. An association between NUAK2 and MRIP reveals a novel mechanism for regulation of actin stress fibers. J Cell Sci 2011; 124:384-93. [PMID: 21242312 DOI: 10.1242/jcs.072660] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Actin stress fiber assembly and contractility in nonmuscle motile cells requires phosphorylation of myosin regulatory light chain (MLC). Dephosphorylation and disassembly are mediated by MLC phosphatase, which is targeted to actin fibers by the association of its regulatory subunit MYPT1 with myosin phosphatase Rho-interacting protein (MRIP). In the present study, we identify the kinase NUAK2 as a second protein targeted by MRIP to actin fibers. Association of NUAK2 with MRIP increases MLC phosphorylation and promotes formation of stress fibers. This activity does not require the kinase activity of NUAK2 but is dependent on both MRIP and MYPT1, indicating that the NUAK2-MRIP association inhibits fiber disassembly and MYPT1-mediated MLC dephosphorylation. NUAK2 levels are strongly induced by stimuli increasing actomyosin fiber formation, and NUAK2 is required for fiber maintenance in exponentially growing cells, implicating NUAK2 in a positive-feedback loop regulating actin stress fibers independently of the MLC kinase Rho-associated protein kinase (ROCK). The identified MRIP-NUAK2 association reveals a novel mechanism for the maintenance of actin stress fibers through counteracting MYPT1 and, together with recent results, implicates the NUAK proteins as important regulators of the MLC phosphatase acting in both a kinase-dependent and kinase-independent manner.
Collapse
Affiliation(s)
- Tea Vallenius
- Institute of Biotechnology and Genome-Scale Biology Program, University of Helsinki, PO Box 56 Viikinkaari 9, 00014 University of Helsinki, Finland.
| | | | | | | | | | | |
Collapse
|
98
|
Claudin-7 is frequently overexpressed in ovarian cancer and promotes invasion. PLoS One 2011; 6:e22119. [PMID: 21789222 PMCID: PMC3137611 DOI: 10.1371/journal.pone.0022119] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 06/16/2011] [Indexed: 12/14/2022] Open
Abstract
Background Claudins are tight junction proteins that are involved in tight junction formation and function. Previous studies have shown that claudin-7 is frequently upregulated in epithelial ovarian cancer (EOC) along with claudin-3 and claudin-4. Here, we investigate in detail the expression patterns of claudin-7, as well as its possible functions in EOC. Methodology/Principal Findings A total of 95 ovarian tissue samples (7 normal ovarian tissues, 65 serous carcinomas, 11 clear cell carcinomas, 8 endometrioid carcinomas and 4 mucinous carcinomas) were studied for claudin-7 expression. In real-time RT-PCR analysis, the gene for claudin-7, CLDN7, was found to be upregulated in all the tumor tissue samples studied. Similarly, immunohistochemical analysis and western blotting showed that claudin-7 protein was significantly overexpressed in the vast majority of EOCs. Small interfering RNA-mediated knockdown of claudin-7 in ovarian cancer cells led to significant changes in gene expression as measured by microarrays and validated by RT-PCR and immunoblotting. Analyses of the genes differentially expressed revealed that the genes altered in response to claudin-7 knockdown were associated with pathways implicated in various molecular and cellular functions such as cell cycle, cellular growth and proliferation, cell death, development, and cell movement. Through functional experiments in vitro, we found that both migration and invasion were altered in cells where CLDN7 had been knocked down or overexpressed. Interestingly, claudin-7 expression was associated with a net increase in invasion, but also with a decrease in migration. Conclusion/Significance Our work shows that claudin-7 is significantly upregulated in EOC and that it may be functionally involved in ovarian carcinoma invasion. CLDN7 may therefore represent potential marker for ovarian cancer detection and a target for therapy.
Collapse
|
99
|
Abstract
Raf are conserved, ubiquitous serine/protein kinases discovered as the cellular elements hijacked by transforming retroviruses. The three mammalian RAF proteins (A, B and CRAF) can be activated by the human oncogene RAS, downstream from which they exert both kinase-dependent and kinase-independent, tumor-promoting functions. The kinase-dependent functions are mediated chiefly by the MEK/ERK pathway, whose activation is associated with proliferation in a broad range of human tumors. Almost 10 years ago, activating BRAF mutations were discovered in a subset of human tumors, and in the past year treatment with small-molecule RAF inhibitors has yielded unprecedented response rates in melanoma patients. Thus, Raf qualifies as an excellent molecular target for anticancer therapy. This review focuses on the role of BRAF and CRAF in different aspects of carcinogenesis, on the success of molecular therapies targeting Raf and the challenges they present.
Collapse
|
100
|
Wang Y, Yang F, Fu Y, Huang X, Wang W, Jiang X, Gritsenko MA, Zhao R, Monore ME, Pertz OC, Purvine SO, Orton DJ, Jacobs JM, Camp DG, Smith RD, Klemke RL. Spatial phosphoprotein profiling reveals a compartmentalized extracellular signal-regulated kinase switch governing neurite growth and retraction. J Biol Chem 2011; 286:18190-201. [PMID: 21454597 DOI: 10.1074/jbc.m111.236133] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Brain development and spinal cord regeneration require neurite sprouting and growth cone navigation in response to extension and collapsing factors present in the extracellular environment. These external guidance cues control neurite growth cone extension and retraction processes through intracellular protein phosphorylation of numerous cytoskeletal, adhesion, and polarity complex signaling proteins. However, the complex kinase/substrate signaling networks that mediate neuritogenesis have not been investigated. Here, we compare the neurite phosphoproteome under growth and retraction conditions using neurite purification methodology combined with mass spectrometry. More than 4000 non-redundant phosphorylation sites from 1883 proteins have been annotated and mapped to signaling pathways that control kinase/phosphatase networks, cytoskeleton remodeling, and axon/dendrite specification. Comprehensive informatics and functional studies revealed a compartmentalized ERK activation/deactivation cytoskeletal switch that governs neurite growth and retraction, respectively. Our findings provide the first system-wide analysis of the phosphoprotein signaling networks that enable neurite growth and retraction and reveal an important molecular switch that governs neuritogenesis.
Collapse
Affiliation(s)
- Yingchun Wang
- Department of Pathology and Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|