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Alhaskawi A, Dong YZ, Zou XD, Hasan Abdullah Ezzi S, Wang ZW, Zhou HY, Abdalbary SA, Lu H. Advanced hepatocellular carcinoma in a patient with neurofibromatosis type 1 and malignant peripheral nerve sheath tumor. Hepatobiliary Pancreat Dis Int 2024; 23:530-532. [PMID: 37648555 DOI: 10.1016/j.hbpd.2023.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 08/16/2023] [Indexed: 09/01/2023]
Affiliation(s)
- Ahmad Alhaskawi
- Department of Orthopedics, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Yan-Zhao Dong
- Department of Orthopedics, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Xiao-Di Zou
- Department of Orthopedics, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China; Department of Chinese Medicine, the Second Affiliated Hospital, Zhejiang Chinese Medical University, Hangzhou 310005, China
| | | | - Ze-Wei Wang
- Zhejiang University School of Medicine, Hangzhou 310000, China
| | - Hai-Ying Zhou
- Department of Orthopedics, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Sahar Ahmed Abdalbary
- Department of Orthopedic Physical Therapy, Faculty of Physical Therapy, Nahda University in Beni Suef, Beni Suef, Egypt
| | - Hui Lu
- Department of Orthopedics, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China.
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2
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Tzenaki N, Xenou L, Goulielmaki E, Tsapara A, Voudouri I, Antoniou A, Valianatos G, Tzardi M, De Bree E, Berdiaki A, Makrigiannakis A, Papakonstanti EA. A combined opposite targeting of p110δ PI3K and RhoA abrogates skin cancer. Commun Biol 2024; 7:26. [PMID: 38182748 PMCID: PMC10770346 DOI: 10.1038/s42003-023-05639-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 11/27/2023] [Indexed: 01/07/2024] Open
Abstract
Malignant melanoma is the most aggressive and deadly skin cancer with an increasing incidence worldwide whereas SCC is the second most common non-melanoma human skin cancer with limited treatment options. Here we show that the development and metastasis of melanoma and SCC cancers can be blocked by a combined opposite targeting of RhoA and p110δ PI3K. We found that a targeted induction of RhoA activity into tumours by deletion of p190RhoGAP-a potent inhibitor of RhoA GTPase-in tumour cells together with adoptive macrophages transfer from δD910A/D910A mice in mice bearing tumours with active RhoA abrogated growth progression of melanoma and SCC tumours. Τhe efficacy of this combined treatment is the same in tumours lacking activating mutations in BRAF and in tumours harbouring the most frequent BRAF(V600E) mutation. Furthermore, the efficiency of this combined treatment is associated with decreased ATX expression in tumour cells and tumour stroma bypassing a positive feedback expression of ATX induced by direct ATX pharmacological inactivation. Together, our findings highlight the importance of targeting cancer cells and macrophages for skin cancer therapy, emerge a reverse link between ATX and RhoA and illustrate the benefit of p110δ PI3K inhibition as a combinatorial regimen for the treatment of skin cancers.
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Affiliation(s)
- Niki Tzenaki
- Department of Biochemistry, School of Medicine, University of Crete, Heraklion, Greece
| | - Lydia Xenou
- Department of Biochemistry, School of Medicine, University of Crete, Heraklion, Greece
| | - Evangelia Goulielmaki
- Department of Biochemistry, School of Medicine, University of Crete, Heraklion, Greece
| | - Anna Tsapara
- Department of Biochemistry, School of Medicine, University of Crete, Heraklion, Greece
| | - Irene Voudouri
- Department of Biochemistry, School of Medicine, University of Crete, Heraklion, Greece
| | - Angelika Antoniou
- Department of Biochemistry, School of Medicine, University of Crete, Heraklion, Greece
| | - George Valianatos
- Department of Biochemistry, School of Medicine, University of Crete, Heraklion, Greece
| | - Maria Tzardi
- Department of Pathology, School of Medicine, University of Crete, University Hospital, Heraklion, Greece
| | - Eelco De Bree
- Department of Surgical Oncology, School of Medicine, University of Crete, University Hospital, Heraklion, Greece
| | - Aikaterini Berdiaki
- Department of Obstetrics and Gynaecology, School of Medicine, University of Crete, University Hospital, Heraklion, Greece
| | - Antonios Makrigiannakis
- Department of Obstetrics and Gynaecology, School of Medicine, University of Crete, University Hospital, Heraklion, Greece
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3
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p110δ PI3K as a therapeutic target of solid tumours. Clin Sci (Lond) 2020; 134:1377-1397. [DOI: 10.1042/cs20190772] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 05/21/2020] [Accepted: 06/01/2020] [Indexed: 12/12/2022]
Abstract
AbstractFrom the time of first characterization of PI3K as a heterodimer made up of a p110 catalytic subunit and a regulatory subunit, a wealth of evidence have placed the class IA PI3Ks at the forefront of drug development for the treatment of various diseases including cancer. The p110α isoform was quickly brought at the centre of attention in the field of cancer research by the discovery of cancer-specific gain-of-function mutations in PIK3CA gene in a range of human solid tumours. In contrast, p110δ PI3K was placed into the spotlight of immunity, inflammation and haematologic malignancies because of the preferential expression of this isoform in leucocytes and the rare mutations in PIK3CD gene. The last decade, however, several studies have provided evidence showing that the correlation between the PIK3CA mutations and the response to PI3K inhibition is less clear than originally considered, whereas concurrently an unexpected role of p110δ PI3K in solid tumours has being emerging. While PIK3CD is mostly non-mutated in cancer, the expression levels of p110δ protein seem to act as an intrinsic cancer-causing driver in various solid tumours including breast, prostate, colorectal and liver cancer, Merkel-Cell carcinoma, glioblastoma and neurobalstoma. Furthermore, p110δ selective inhibitors are being studied as potential single agent treatments or as combination partners in attempt to improve cancer immunotherapy, with both strategies to shown great promise for the treatment of several solid tumours. In this review, we discuss the evidence implicating the p110δ PI3K in human solid tumours, their impact on the current state of the field and the potential of using p110δ-selective inhibitors as monotherapy or combined therapy in different cancer contexts.
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4
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Li L, Cheng Y, Lin L, Liu Z, Du S, Ma L, Li J, Peng Z, Yan J. Global Analysis of miRNA Signature Differentially Expressed in Insulin-resistant Human Hepatocellular Carcinoma Cell Line. Int J Med Sci 2020; 17:664-677. [PMID: 32210717 PMCID: PMC7085209 DOI: 10.7150/ijms.41999] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/21/2020] [Indexed: 12/27/2022] Open
Abstract
Chemoresistance mediated by insulin resistance (IR) in HCC has already been validated. However, the underlying mechanism, especially the involvement of microRNAs (miRNAs) was unelucidated. In this study, miRNA microarrays and bioinformatics methods were employed to determine the dysregulation of miRNA by IR in HCC cells, and quantitative RT-PCR (qRT-PCR) was applied to valid the miRNA array data. Of all the 2006 miRNAs screened, 32 miRNAs were found up or down regulated between the HepG2/IR cells and its parental cells. Further literature mining revealed that some of these miRNAs may function as oncogenes or tumor suppressors that contribute to tumor progression, recurrence, and metastasis which eventually lead to chemotherapeutic resistance. Interestingly, bioinformatics analysis by Gene Ontology (GO) enrichment pathway indicating that function of the predicted target genes of these dysregulated miRNAs were significantly enriched in the processes related with biosynthesis, catabolism, modification etc., and Kyoto Encyclopedia of Genes and Genomes (KEGG) mapping showed that the biological regulatory mechanisms were integrated in cancer-related pathways. Moreover, we also constructed a network which connected the differentially expressed miRNAs to target genes, GO enrichments and KEGG pathways to reveal the hub miRNAs, genes and pathways. Collectively, our present study demonstrated the possible miRNAs and predicted target genes involving in the pathophysiology of insulin resistant HCC, providing novel insights into the molecular mechanisms of multidrug resistance in the insulin resistant HepG2 cells.
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Affiliation(s)
- Linjing Li
- Department of Clinical Laboratory Center, The Second Hospital of Lanzhou University, Lanzhou 730000, P.R. China
| | - Yan Cheng
- Northwest University for Nationalities, Lanzhou 730000, P.R. China
| | - Li Lin
- Hematology Department, Gansu Provincial Cancer Hospital, Lanzhou, Gansu 730000, China
| | - Zhuan Liu
- Department of Clinical Laboratory Center, The Second Hospital of Lanzhou University, Lanzhou 730000, P.R. China
| | - Shengfang Du
- Department of Anesthesiology, the Second Hospital of Lanzhou University, Lanzhou 730000, P.R. China
| | - Li Ma
- Department of Clinical Laboratory Center, The Second Hospital of Lanzhou University, Lanzhou 730000, P.R. China
| | - Jing Li
- Department of Clinical Laboratory Center, The Second Hospital of Lanzhou University, Lanzhou 730000, P.R. China
| | - Zhiheng Peng
- Department of Clinical Laboratory Center, The Second Hospital of Lanzhou University, Lanzhou 730000, P.R. China
| | - Jing Yan
- Department of Clinical Laboratory Center, The Second Hospital of Lanzhou University, Lanzhou 730000, P.R. China
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5
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Scheffzek K, Shivalingaiah G. Ras-Specific GTPase-Activating Proteins-Structures, Mechanisms, and Interactions. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a031500. [PMID: 30104198 DOI: 10.1101/cshperspect.a031500] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ras-specific GTPase-activating proteins (RasGAPs) down-regulate the biological activity of Ras proteins by accelerating their intrinsic rate of GTP hydrolysis, basically by a transition state stabilizing mechanism. Oncogenic Ras is commonly not sensitive to RasGAPs caused by interference of mutants with the electronic or steric requirements of the transition state, resulting in up-regulation of activated Ras in respective cells. RasGAPs are modular proteins containing a helical catalytic RasGAP module surrounded by smaller domains that are frequently involved in the subcellular localization or contributing to regulatory features of their host proteins. In this review, we summarize current knowledge about RasGAP structure, mechanism, regulation, and dual-substrate specificity and discuss in some detail neurofibromin, one of the most important negative Ras regulators in cellular growth control and neuronal function.
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Affiliation(s)
- Klaus Scheffzek
- Division of Biological Chemistry (Biocenter), Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Giridhar Shivalingaiah
- Division of Biological Chemistry (Biocenter), Medical University of Innsbruck, A-6020 Innsbruck, Austria
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6
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Molosh AI, Shekhar A. Neurofibromatosis type 1 as a model system to study molecular mechanisms of autism spectrum disorder symptoms. PROGRESS IN BRAIN RESEARCH 2018; 241:37-62. [PMID: 30447756 DOI: 10.1016/bs.pbr.2018.09.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neurofibromatosis type 1 (NF1) is monogenic neurodevelopmental disorder caused by mutation of NF1 gene, which leads to increased susceptibility to various tumors formations. Additionally, majority of patients with NF1 are experience high incidence of cognitive deficits. Particularly, we review the growing number of reports demonstrated a higher incidence of autism spectrum disorder (ASD) in individuals with NF1. In this review we also discuss face validity of preclinical Nf1 mouse models. Then we describe discoveries from these animal models that have uncovered the deficiencies in the regulation of Ras and other intracellular pathways as critical mechanisms underlying the Nf1 cognitive problems. We also summarize and interpret recent preclinical and clinical studies that point toward potential pharmacological therapies for NF1 patients.
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Affiliation(s)
- Andrei I Molosh
- Department of Psychiatry, Institute of Psychiatric Research, IU School of Medicine, Indianapolis, IN, United States; Stark Neurosciences Research Institute, IU School of Medicine, Indianapolis, IN, United States.
| | - Anantha Shekhar
- Department of Psychiatry, Institute of Psychiatric Research, IU School of Medicine, Indianapolis, IN, United States; Stark Neurosciences Research Institute, IU School of Medicine, Indianapolis, IN, United States; Department of Pharmacology & Toxicology, IU School of Medicine, Indianapolis, IN, United States; Indiana Clinical and Translational Institute, IU School of Medicine, Indianapolis, IN, United States
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7
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Cirenajwis H, Lauss M, Ekedahl H, Törngren T, Kvist A, Saal LH, Olsson H, Staaf J, Carneiro A, Ingvar C, Harbst K, Hayward NK, Jönsson G. NF1-mutated melanoma tumors harbor distinct clinical and biological characteristics. Mol Oncol 2017; 11:438-451. [PMID: 28267273 PMCID: PMC5527484 DOI: 10.1002/1878-0261.12050] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 02/14/2017] [Accepted: 02/14/2017] [Indexed: 12/30/2022] Open
Abstract
In general, melanoma can be considered as a UV‐driven disease with an aggressive metastatic course and high mutational load, with only few tumors (acral, mucosal, and uveal melanomas) not induced by sunlight and possessing a lower mutational load. The most commonly activated pathway in melanoma is the mitogen‐activated protein kinase (MAPK) pathway. However, the prognostic significance of mutational stratification is unclear and needs further investigation. Here, in silico we combined mutation data from 162 melanomas subjected to targeted deep sequencing with mutation data from three published studies. Tumors from 870 patients were grouped according to BRAF,RAS,NF1 mutation or triple‐wild‐type status and correlated with tumor and patient characteristics. We found that the NF1‐mutated subtype had a higher mutational burden and strongest UV mutation signature. Searching for co‐occurring mutated genes revealed the RASopathy genes PTPN11 and RASA2, as well as another RAS domain‐containing gene RASSF2 enriched in the NF1 subtype after adjustment for mutational burden. We found that a larger proportion of the NF1‐mutant tumors were from males and with older age at diagnosis. Importantly, we found an increased risk of death from melanoma (disease‐specific survival, DSS; HR, 1.9; 95% CI, 1.21–3.10; P = 0.046) and poor overall survival (OS; HR, 2.0; 95% CI, 1.28–2.98; P = 0.01) in the NF1 subtype, which remained significant after adjustment for age, gender, and lesion type (DSS P = 0.03, OS P = 0.06, respectively). Melanoma genomic subtypes display different biological and clinical characteristics. The poor outcome observed in the NF1 subtype highlights the need for improved characterization of this group.
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Affiliation(s)
- Helena Cirenajwis
- Division of Oncology and Pathology, Department of Clinical Sciences, Lund University, Sweden
| | - Martin Lauss
- Division of Oncology and Pathology, Department of Clinical Sciences, Lund University, Sweden
| | - Henrik Ekedahl
- Division of Surgery, Department of Clinical Sciences, Lund University, Sweden
| | - Therese Törngren
- Division of Oncology and Pathology, Department of Clinical Sciences, Lund University, Sweden
| | - Anders Kvist
- Division of Oncology and Pathology, Department of Clinical Sciences, Lund University, Sweden
| | - Lao H Saal
- Division of Oncology and Pathology, Department of Clinical Sciences, Lund University, Sweden
| | - Håkan Olsson
- Division of Oncology and Pathology, Department of Clinical Sciences, Lund University, Sweden.,Department of Oncology, Skåne University Hospital, Lund University, Sweden
| | - Johan Staaf
- Division of Oncology and Pathology, Department of Clinical Sciences, Lund University, Sweden
| | - Ana Carneiro
- Division of Oncology and Pathology, Department of Clinical Sciences, Lund University, Sweden.,Department of Oncology, Skåne University Hospital, Lund University, Sweden
| | - Christian Ingvar
- Division of Surgery, Department of Clinical Sciences, Lund University, Sweden
| | - Katja Harbst
- Division of Oncology and Pathology, Department of Clinical Sciences, Lund University, Sweden
| | | | - Göran Jönsson
- Division of Oncology and Pathology, Department of Clinical Sciences, Lund University, Sweden
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8
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Huang GH, Sun ZL, Li HJ, Feng DF. Rho GTPase-activating proteins: Regulators of Rho GTPase activity in neuronal development and CNS diseases. Mol Cell Neurosci 2017; 80:18-31. [PMID: 28163190 DOI: 10.1016/j.mcn.2017.01.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 01/06/2017] [Accepted: 01/29/2017] [Indexed: 12/22/2022] Open
Abstract
The Rho family of small GTPases was considered as molecular switches in regulating multiple cellular events, including cytoskeleton reorganization. The Rho GTPase-activating proteins (RhoGAPs) are one of the major families of Rho GTPase regulators. RhoGAPs were initially considered negative mediators of Rho signaling pathways via their GAP domain. Recent studies have demonstrated that RhoGAPs also regulate numerous aspects of neuronal development and are related to various neurodegenerative diseases in GAP-dependent and GAP-independent manners. Moreover, RhoGAPs are regulated through various mechanisms, such as phosphorylation. To date, approximately 70 RhoGAPs have been identified; however, only a small portion has been thoroughly investigated. Thus, the characterization of important RhoGAPs in the central nervous system is crucial to understand their spatiotemporal role during different stages of neuronal development. In this review, we summarize the current knowledge of RhoGAPs in the brain with an emphasis on their molecular function, regulation mechanism and disease implications in the central nervous system.
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Affiliation(s)
- Guo-Hui Huang
- Department of Neurosurgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201900, China
| | - Zhao-Liang Sun
- Department of Neurosurgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201900, China
| | - Hong-Jiang Li
- Department of Neurosurgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201900, China
| | - Dong-Fu Feng
- Department of Neurosurgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 201900, China; Institute of Traumatic Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 201900, China.
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9
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Parasuraman P, Mulligan P, Walker JA, Li B, Boukhali M, Haas W, Bernards A. Interaction of p190A RhoGAP with eIF3A and Other Translation Preinitiation Factors Suggests a Role in Protein Biosynthesis. J Biol Chem 2016; 292:2679-2689. [PMID: 28007963 DOI: 10.1074/jbc.m116.769216] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Indexed: 11/06/2022] Open
Abstract
The negative regulator of Rho family GTPases, p190A RhoGAP, is one of six mammalian proteins harboring so-called FF motifs. To explore the function of these and other p190A segments, we identified interacting proteins by tandem mass spectrometry. Here we report that endogenous human p190A, but not its 50% identical p190B paralog, associates with all 13 eIF3 subunits and several other translational preinitiation factors. The interaction involves the first FF motif of p190A and the winged helix/PCI domain of eIF3A, is enhanced by serum stimulation and reduced by phosphatase treatment. The p190A/eIF3A interaction is unaffected by mutating phosphorylated p190A-Tyr308, but disrupted by a S296A mutation, targeting the only other known phosphorylated residue in the first FF domain. The p190A-eIF3 complex is distinct from eIF3 complexes containing S6K1 or mammalian target of rapamycin (mTOR), and appears to represent an incomplete preinitiation complex lacking several subunits. Based on these findings we propose that p190A may affect protein translation by controlling the assembly of functional preinitiation complexes. Whether such a role helps to explain why, unique among the large family of RhoGAPs, p190A exhibits a significantly increased mutation rate in cancer remains to be determined.
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Affiliation(s)
- Prasanna Parasuraman
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
| | - Peter Mulligan
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
| | - James A Walker
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
| | - Bihua Li
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
| | - Myriam Boukhali
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
| | - Wilhelm Haas
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
| | - Andre Bernards
- From the Massachusetts General Hospital Center for Cancer Research and Harvard Medical School, Charlestown, Massachusetts 02129
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10
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Hong Y, Han YQ, Wang YZ, Gao JR, Li YX, Liu Q, Xia LZ. Paridis Rhizoma Sapoinins attenuates liver fibrosis in rats by regulating the expression of RASAL1/ERK1/2 signal pathway. JOURNAL OF ETHNOPHARMACOLOGY 2016; 192:114-122. [PMID: 27396351 DOI: 10.1016/j.jep.2016.07.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 05/10/2016] [Accepted: 07/06/2016] [Indexed: 06/06/2023]
Abstract
ETHNO-PHARMACOLOGICAL RELEVANCE Paridis Rhizoma is a Chinese medicinal herb that has been used in liver disease treatment for thousands of years. Our previous studies found that Paridis Rhizoma saponins (PRS) are the critical components of Paridis Rhizoma which has good liver protection effect. However, the anti-hepatic fibrosis effect and the mechanism of PRS have seldom been reported. AIM OF THE STUDY To investigate the potential of PRS in the treatment of experimental liver fibrosis and the underlying mechanism. MATERIALS AND METHODS The chemical feature fingerprint of PRS was analyzed by UPLC-PDA. A total of 40 Male Sprague-Dawley (SD) rats were randomly divided into the control group, the model group, the PRS high dose group (PRS H) and the PRS low dose group (PRS L) with 10 rats in each group. The model, PRS H and L groups as liver fibrosis models were established with carbon tetrachloride (CCl4) method. PRS H and L groups were adopted PRS (300 and 150mg/kgd-1) treatment since the twelfth week of modeling till the sixteenth week. Pathological changes in hepatic tissue were examined using hematoxylin and eosin (H&E) and MASSON trichrome staining. Immunohistochemical analysis was performed to determine the protein expression of the RASAL1. RT-PCR and western blotting were used to detect the expression of ERK1/2 mRNA and protein. RESULTS Four saponins in PRS were identified from 19 detected chromatographic peaks on UPLC-PDA by comparing to the standard compounds. PRS can improve the degeneration and necrosis of hepatic tissue, reduce the extent of its fibrous hyperplasia according to H&E and MASSON staining detection. As was detected in PRS H and L groups, PRS down-regulated p-ERK1/2 mRNA and RASAL1 protein, and up-regulated the level of p-ERK1/2 mRNA and RASAL1 protein. CONCLUSION These results demonstrated that PRS can attenuate CCl4-induced liver fibrosis through the regulation of RAS/ERK1/2 signal pathway.
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MESH Headings
- Animals
- Blotting, Western
- Carbon Tetrachloride
- Chemical and Drug Induced Liver Injury/enzymology
- Chemical and Drug Induced Liver Injury/pathology
- Chemical and Drug Induced Liver Injury/prevention & control
- Chromatography, High Pressure Liquid
- Cytoprotection
- GTPase-Activating Proteins/genetics
- GTPase-Activating Proteins/metabolism
- Gene Expression Regulation, Enzymologic
- Hyperplasia
- Immunohistochemistry
- Liver/drug effects
- Liver/enzymology
- Liver/pathology
- Liver Cirrhosis, Experimental/chemically induced
- Liver Cirrhosis, Experimental/enzymology
- Liver Cirrhosis, Experimental/pathology
- Liver Cirrhosis, Experimental/prevention & control
- Male
- Melanthiaceae/chemistry
- Mitogen-Activated Protein Kinase 1/genetics
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3/genetics
- Mitogen-Activated Protein Kinase 3/metabolism
- Necrosis
- Phosphorylation
- Phytotherapy
- Plant Extracts/isolation & purification
- Plant Extracts/pharmacology
- Plants, Medicinal
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats, Sprague-Dawley
- Reverse Transcriptase Polymerase Chain Reaction
- Saponins/isolation & purification
- Saponins/pharmacology
- Signal Transduction/drug effects
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Affiliation(s)
- Yan Hong
- Anhui University of Chinese Medicine, Hefei, Anhui 230031, China.
| | - Yan-Quan Han
- The First Affiliated Hospital, Anhui University of Chinese Medicine, Grade 3 Laboratory of TCM Preparation, State Administration of Anhui University of Chinese Medicine, Hefei, Anhui 230031, China.
| | - Yong-Zhong Wang
- The First Affiliated Hospital, Anhui University of Chinese Medicine, Grade 3 Laboratory of TCM Preparation, State Administration of Anhui University of Chinese Medicine, Hefei, Anhui 230031, China.
| | - Jia-Rong Gao
- The First Affiliated Hospital, Anhui University of Chinese Medicine, Grade 3 Laboratory of TCM Preparation, State Administration of Anhui University of Chinese Medicine, Hefei, Anhui 230031, China.
| | - Yu-Xin Li
- Anhui University of Chinese Medicine, Hefei, Anhui 230031, China; The First Affiliated Hospital, Anhui University of Chinese Medicine, Grade 3 Laboratory of TCM Preparation, State Administration of Anhui University of Chinese Medicine, Hefei, Anhui 230031, China.
| | - Qing Liu
- Anhui University of Chinese Medicine, Hefei, Anhui 230031, China; The First Affiliated Hospital, Anhui University of Chinese Medicine, Grade 3 Laboratory of TCM Preparation, State Administration of Anhui University of Chinese Medicine, Hefei, Anhui 230031, China.
| | - Lun-Zhu Xia
- The First Affiliated Hospital, Anhui University of Chinese Medicine, Grade 3 Laboratory of TCM Preparation, State Administration of Anhui University of Chinese Medicine, Hefei, Anhui 230031, China.
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11
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Liu L, Xu C, Hsieh JT, Gong J, Xie D. DAB2IP in cancer. Oncotarget 2016; 7:3766-76. [PMID: 26658103 PMCID: PMC4826168 DOI: 10.18632/oncotarget.6501] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/15/2015] [Indexed: 12/17/2022] Open
Abstract
DOC-2/DAB2 is a member of the disable gene family that features tumor-inhibiting activity. The DOC-2/DAB2 interactive protein, DAB2IP, is a new member of the Ras GTPase-activating protein family. It interacts directly with DAB2 and has distinct cellular functions such as modulating different signal cascades associated with cell proliferation, survival, apoptosis and metastasis. Recently, DAB2IP has been found significantly down regulated in multiple types of cancer. The aberrant alteration of DAB2IP in cancer is caused by a variety of mechanisms, including the aberrant promoter methylation, histone deacetylation, and others. Reduced expression of DAB2IP in neoplasm may indicate a poor prognosis of many malignant cancers. Moreover, DAB2IP stands for a promising direction for developing targeted therapies due to its capacity to inhibit tumor cell growth in vitro and in vivo. Here, we summarize the present understanding of the tumor suppressive role of DAB2IP in cancer progression; the mechanisms underlying the dysregulation of DAB2IP; the gene functional mechanism and the prospects of DAB2IP in the future cancer research.
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Affiliation(s)
- Liang Liu
- Tongji Cancer Research Institute, Tongji Hospital, Tongji Medical College in Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.,Department of Gastrointestinal Surgery, Tongji Hospital, Tongji Medical College in Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Cong Xu
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College in Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Jer-Tsong Hsieh
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jianping Gong
- Tongji Cancer Research Institute, Tongji Hospital, Tongji Medical College in Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.,Department of Gastrointestinal Surgery, Tongji Hospital, Tongji Medical College in Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Daxing Xie
- Tongji Cancer Research Institute, Tongji Hospital, Tongji Medical College in Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.,Department of Gastrointestinal Surgery, Tongji Hospital, Tongji Medical College in Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
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Amin E, Jaiswal M, Derewenda U, Reis K, Nouri K, Koessmeier KT, Aspenström P, Somlyo AV, Dvorsky R, Ahmadian MR. Deciphering the Molecular and Functional Basis of RHOGAP Family Proteins: A SYSTEMATIC APPROACH TOWARD SELECTIVE INACTIVATION OF RHO FAMILY PROTEINS. J Biol Chem 2016; 291:20353-71. [PMID: 27481945 PMCID: PMC5034035 DOI: 10.1074/jbc.m116.736967] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/15/2016] [Indexed: 12/30/2022] Open
Abstract
RHO GTPase-activating proteins (RHOGAPs) are one of the major classes of regulators of the RHO-related protein family that are crucial in many cellular processes, motility, contractility, growth, differentiation, and development. Using database searches, we extracted 66 distinct human RHOGAPs, from which 57 have a common catalytic domain capable of terminating RHO protein signaling by stimulating the slow intrinsic GTP hydrolysis (GTPase) reaction. The specificity of the majority of the members of RHOGAP family is largely uncharacterized. Here, we comprehensively investigated the sequence-structure-function relationship between RHOGAPs and RHO proteins by combining our in vitro data with in silico data. The activity of 14 representatives of the RHOGAP family toward 12 RHO family proteins was determined in real time. We identified and structurally verified hot spots in the interface between RHOGAPs and RHO proteins as critical determinants for binding and catalysis. We have found that the RHOGAP domain itself is nonselective and in some cases rather inefficient under cell-free conditions. Thus, we propose that other domains of RHOGAPs confer substrate specificity and fine-tune their catalytic efficiency in cells.
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Affiliation(s)
- Ehsan Amin
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Mamta Jaiswal
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Urszula Derewenda
- the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908, and
| | - Katarina Reis
- the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Kazem Nouri
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Katja T Koessmeier
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Pontus Aspenström
- the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Avril V Somlyo
- the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908, and
| | - Radovan Dvorsky
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany,
| | - Mohammad R Ahmadian
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany,
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Hennig A, Markwart R, Esparza-Franco MA, Ladds G, Rubio I. Ras activation revisited: role of GEF and GAP systems. Biol Chem 2016; 396:831-48. [PMID: 25781681 DOI: 10.1515/hsz-2014-0257] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 03/09/2015] [Indexed: 12/13/2022]
Abstract
Ras is a prototypical small G-protein and a central regulator of growth, proliferation and differentiation processes in virtually every nucleated cell. As such, Ras becomes engaged and activated by multiple growth factors, mitogens, cytokines or adhesion receptors. Ras activation comes about by changes in the steady-state equilibrium between the inactive guanosine diphosphate (GDP)-bound and active guanosine triphosphate (GTP)-bound states of Ras, resulting in the mostly transient accumulation of Ras-GTP. Three decades of intense Ras research have disclosed various families of guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs) as the two principal regulatory elements of the Ras-GDP/GTP loading status. However, with the possible exception of the GEF Sos, we still have only a rudimentary knowledge of the precise role played by many GEF and GAP members in the signalling network upstream of Ras. As for GAPs, we even lack the fundamental understanding of whether they function as genuine signal transducers in the context of growth factor-elicited Ras activation or rather act as passive modulators of the Ras-GDP/GTP cycle. Here we sift through the large body of Ras literature and review the relevant data for understanding the participation and precise role played by GEFs and GAPs in the process of Ras activation.
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Karachaliou N, Pilotto S, Teixidó C, Viteri S, González-Cao M, Riso A, Morales-Espinosa D, Molina MA, Chaib I, Santarpia M, Richardet E, Bria E, Rosell R. Melanoma: oncogenic drivers and the immune system. ANNALS OF TRANSLATIONAL MEDICINE 2015; 3:265. [PMID: 26605311 PMCID: PMC4630557 DOI: 10.3978/j.issn.2305-5839.2015.08.06] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 08/04/2015] [Indexed: 12/19/2022]
Abstract
Advances and in-depth understanding of the biology of melanoma over the past 30 years have contributed to a change in the consideration of melanoma as one of the most therapy-resistant malignancies. The finding that oncogenic BRAF mutations drive tumor growth in up to 50% of melanomas led to a molecular therapy revolution for unresectable and metastatic disease. Moving beyond BRAF, inactivation of immune regulatory checkpoints that limit T cell responses to melanoma has provided targets for cancer immunotherapy. In this review, we discuss the molecular biology of melanoma and we focus on the recent advances of molecularly targeted and immunotherapeutic approaches.
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Maertens O, Cichowski K. An expanding role for RAS GTPase activating proteins (RAS GAPs) in cancer. Adv Biol Regul 2014; 55:1-14. [PMID: 24814062 DOI: 10.1016/j.jbior.2014.04.002] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 04/16/2014] [Accepted: 04/16/2014] [Indexed: 10/25/2022]
Abstract
The RAS pathway is one of the most commonly deregulated pathways in human cancer. Mutations in RAS genes occur in nearly 30% of all human tumors. However in some tumor types RAS mutations are conspicuously absent or rare, despite the fact that RAS and downstream effector pathways are hyperactivated. Recently, RAS GTPase Activating Proteins (RAS GAPs) have emerged as an expanding class of tumor suppressors that, when inactivated, provide an alternative mechanism of activating RAS. RAS GAPs normally turn off RAS by catalyzing the hydrolysis of RAS-GTP. As such, the loss of a RAS GAP would be expected to promote excessive RAS activation. Indeed, this is the case for the NF1 gene, which plays an established role in a familial tumor predisposition syndrome and a variety of sporadic cancers. However, there are 13 additional RAS GAP family members in the human genome. We are only now beginning to understand why there are so many RAS GAPs, how they differentially function, and what their potential role(s) in human cancer are. This review will focus on our current understanding of RAS GAPs in human disease and will highlight important outstanding questions.
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Affiliation(s)
- Ophélia Maertens
- Genetics Division, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Karen Cichowski
- Genetics Division, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA; Ludwig Center at Dana-Farber/Harvard Cancer Center, Boston, MA 02115, USA.
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16
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Chen H, Cheng ZY, Pan Y, Wang Z, Liu Y, Zhang JQ. RASAL1 influences the proliferation and invasion of gastric cancer cells by regulating the RAS/ERK signaling pathway. Hum Cell 2014; 27:103-10. [PMID: 24531877 DOI: 10.1007/s13577-014-0090-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 01/21/2014] [Indexed: 12/17/2022]
Abstract
The aim of this study was to investigate the biological characteristics of the RASAL1 gene in a well-differentiated gastric cancer cell line MKN-28 and a poorly differentiated gastric cancer cell line BGC-823 cells, using RNA interference and gene transfection technology, respectively. MKN-28 cells were transfected with the shRNA of RASAL1 and BGC-823 cells were transfected with the pcDNA 3.1 plasmid vector containing RASAL1. RT-PCR and western blotting were then used to detect the expression of RASAL1 mRNA and protein. The activities of RAS and extracellular signal-regulated kinase 1/2 were analyzed by the pull-down method and western blotting. The proliferate capacity, apoptosis rate, invasive and migratory potentials of MKN-28 or BGC-823 cells were also measured by Cell Counting Kit-8 cell proliferation assay, propidium iodide/Annexin V staining coupled with flow cytometry, and transwell chamber assays, respectively. Measurement of RASAL1 mRNA and protein expression in two cells revealed successful transfection of the shRNA of RASAL1 and RASAL1-pcDNA3.1 plasmid into these two cells. Moreover, decreased expression of RASAL1 in MKN-28 cells resulted in increased expression of RAS-GTP and p-ERK1/2. Interestingly, decreased expression of RASAL1 inhibited apoptosis and facilitated cell proliferation, invasion and migration. The increased expression of RASAL1 in BGC-823 cells caused declined expression of RAS-GTP and p-ERK1/2, as well as promoted apoptosis and restrained cell proliferation, invasion and migration. The down-regulation of RASAL1 promoted the proliferation, invasion and migration of gastric cancer MKN-28 cells, and up-regulation of RASAL1 inhibited the proliferation, invasion and migration of BGC-823 gastric cancer cells by regulating the RAS/ERK signaling pathway. Thus, our results suggest that RASAL1 may play an important role as a tumor suppressor gene in gastric cancer.
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Affiliation(s)
- Hong Chen
- Department of Gastroenterology, Zhongda Hospital, Southeast University, Nanjing, 210009, Jiangsu, People's Republic of China,
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Maertens O, Johnson B, Hollstein P, Frederick DT, Cooper ZA, Messiaen L, Bronson RT, McMahon M, Granter S, Flaherty K, Wargo JA, Marais R, Cichowski K. Elucidating distinct roles for NF1 in melanomagenesis. Cancer Discov 2013; 3:338-49. [PMID: 23171796 PMCID: PMC3595355 DOI: 10.1158/2159-8290.cd-12-0313] [Citation(s) in RCA: 180] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BRAF mutations play a well-established role in melanomagenesis; however, without additional genetic alterations, tumor development is restricted by oncogene-induced senescence (OIS). Here, we show that mutations in the NF1 tumor suppressor gene cooperate with BRAF mutations in melanomagenesis by preventing OIS. In a genetically engineered mouse model, Nf1 mutations suppress Braf-induced senescence, promote melanocyte hyperproliferation, and enhance melanoma development. Nf1 mutations function by deregulating both phosphoinositide 3-kinase and extracellular signal-regulated kinase pathways. As such, Nf1/Braf-mutant tumors are resistant to BRAF inhibitors but are sensitive to combined inhibition of mitogen-activated protein/extracellular signal-regulated kinase kinase and mTOR. Importantly, NF1 is mutated or suppressed in human melanomas that harbor concurrent BRAF mutations, NF1 ablation decreases the sensitivity of melanoma cell lines to BRAF inhibitors, and NF1 is lost in tumors from patients following treatment with these agents. Collectively, these studies provide mechanistic insight into how NF1 cooperates with BRAF mutations in melanoma and show that NF1/neurofibromin inactivation may have an impact on responses to targeted therapies.
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Affiliation(s)
- Ophélia Maertens
- Genetics Division, Department of Medicine, Brigham and Women’s Hospital, Boston MA 02115
- Harvard Medical School, Boston MA 02115
| | - Bryan Johnson
- Genetics Division, Department of Medicine, Brigham and Women’s Hospital, Boston MA 02115
- Harvard Medical School, Boston MA 02115
| | - Pablo Hollstein
- Genetics Division, Department of Medicine, Brigham and Women’s Hospital, Boston MA 02115
- Harvard Medical School, Boston MA 02115
| | - Dennie T. Frederick
- Division of Surgical Oncology, Medical Oncology and Dermatology, Massachusetts General Hospital, Boston, MA 02114
| | - Zachary A. Cooper
- Division of Surgical Oncology, Medical Oncology and Dermatology, Massachusetts General Hospital, Boston, MA 02114
| | - Ludwine Messiaen
- Department of Genetics, Medical Genomics Laboratory, University of Alabama at Birmingham, Birmingham, AL 35242
| | | | - Martin McMahon
- Cancer Research Institute & Department of Cell and Molecular Pharmacology, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA 94143
| | - Scott Granter
- Harvard Medical School, Boston MA 02115
- Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115
| | - Keith Flaherty
- Division of Surgical Oncology, Medical Oncology and Dermatology, Massachusetts General Hospital, Boston, MA 02114
| | - Jennifer A. Wargo
- Division of Surgical Oncology, Medical Oncology and Dermatology, Massachusetts General Hospital, Boston, MA 02114
| | - Richard Marais
- The Patterson Institute for Cancer Research, The University of Manchester, Manchester, UK
| | - Karen Cichowski
- Genetics Division, Department of Medicine, Brigham and Women’s Hospital, Boston MA 02115
- Harvard Medical School, Boston MA 02115
- Ludwig Center at Dana-Farber/Harvard Cancer Center, Boston, MA 02115
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Tzenaki N, Papakonstanti EA. p110δ PI3 kinase pathway: emerging roles in cancer. Front Oncol 2013; 3:40. [PMID: 23459844 PMCID: PMC3585436 DOI: 10.3389/fonc.2013.00040] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 02/12/2013] [Indexed: 12/11/2022] Open
Abstract
Class IA PI3Ks consists of three isoforms of the p110 catalytic subunit designated p110α, p110β, and p110δ which are encoded by three separate genes. Gain-of-function mutations on PIK3CA gene encoding for p110α isoform have been detected in a wide variety of human cancers whereas no somatic mutations of genes encoding for p110β or p110δ have been reported. Unlike p110α and p110β which are ubiquitously expressed, p110δ is highly enriched in leukocytes and thus the p110δ PI3K pathway has attracted more attention for its involvement in immune disorders. However, findings have been accumulated showing that the p110δ PI3K plays a seminal role in the development and progression of some hematologic malignancies. A wealth of knowledge has come from studies showing the central role of p110δ PI3K in B-cell functions and B-cell malignancies. Further data have documented that wild-type p110δ becomes oncogenic when overexpressed in cell culture models and that p110δ is the predominant isoform expressed in some human solid tumor cells playing a prominent role in these cells. Genetic inactivation of p110δ in mice models and highly-selective inhibitors of p110δ have demonstrated an important role of this isoform in differentiation, growth, survival, motility, and morphology with the inositol phosphatase PTEN to play a critical role in p110δ signaling. In this review, we summarize our understanding of the p110δ PI3K signaling pathway in hematopoietic cells and malignancies, we highlight the evidence showing the oncogenic potential of p110δ in cells of non-hematopoietic origin and we discuss perspectives for potential novel roles of p110δ PI3K in cancer.
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Affiliation(s)
- Niki Tzenaki
- Department of Biochemistry, School of Medicine, University of Crete Heraklion, Greece
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Beck S, Fotinos A, Lang F, Gawaz M, Elvers M. Isoform-specific roles of the GTPase activating protein Nadrin in cytoskeletal reorganization of platelets. Cell Signal 2013; 25:236-46. [DOI: 10.1016/j.cellsig.2012.09.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 09/04/2012] [Indexed: 01/10/2023]
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Hong JY, Park JI, Lee M, Muñoz WA, Miller RK, Ji H, Gu D, Ezan J, Sokol SY, McCrea PD. Down's-syndrome-related kinase Dyrk1A modulates the p120-catenin-Kaiso trajectory of the Wnt signaling pathway. J Cell Sci 2012; 125:561-9. [PMID: 22389395 DOI: 10.1242/jcs.086173] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The Wnt pathways contribute to many processes in cancer and development, with β-catenin being a key canonical component. p120-catenin, which is structurally similar to β-catenin, regulates the expression of certain Wnt target genes, relieving repression conferred by the POZ- and zinc-finger-domain-containing transcription factor Kaiso. We have identified the kinase Dyrk1A as a component of the p120-catenin-Kaiso trajectory of the Wnt pathway. Using rescue and other approaches in Xenopus laevis embryos and mammalian cells, we found that Dyrk1A positively and selectively modulates p120-catenin protein levels, thus having an impact on p120-catenin and Kaiso (and canonical Wnt) gene targets such as siamois and wnt11. The Dyrk1A gene resides within the Down's syndrome critical region, which is amplified in Down's syndrome. A consensus Dyrk phosphorylation site in p120-catenin was identified, with a mutant mimicking phosphorylation exhibiting the predicted enhanced capacity to promote endogenous Wnt-11 and Siamois expression, and gastrulation defects. In summary, we report the biochemical and functional relationship of Dyrk1A with the p120-catenin-Kaiso signaling trajectory, with a linkage to canonical Wnt target genes. Conceivably, this work might also prove relevant to understanding the contribution of Dyrk1A dosage imbalance in Down's syndrome.
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Affiliation(s)
- Ji Yeon Hong
- Department of Biochemistry and Molecular Biology, University of Texas MD Anderson Cancer Center, Houston, Texas, TX 77030, USA
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21
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Qiao F, Su X, Qiu X, Qian D, Peng X, Chen H, Zhao Z, Fan H. Enforced expression of RASAL1 suppresses cell proliferation and the transformation ability of gastric cancer cells. Oncol Rep 2012; 28:1475-81. [PMID: 22825043 DOI: 10.3892/or.2012.1920] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 06/19/2012] [Indexed: 11/06/2022] Open
Abstract
RAS protein activator like 1 (RASAL1) is a member of the RAS GTPase-activating protein (GAP) family, and it is an important molecule in the regulation of RAS activation. In the present study, we investigated the role of RASAL1 in gastric carcinogenesis. Decreased expression pattern of RASAL1 in gastric cancer tissues and cell lines was found in protein and RNA levels, although there was no statistically significant relationship between RASAL1 and clinicopathological features. Restored expression of RASAL1 induced by DNA methylation inhibitor 5-aza-2'-deoxycytidine (5'-AZA) and HDAC inhibitor trichostatin A (TSA) implied that RASAL1 expression is regulated by epigenetic mechanisms. The biological role of RASAL1 in gastric carcinogenesis was determined by in vitro tumorigenicity assays. Overexpression of RASAL1 showed suppression of cell proliferation due to cell apoptosis. Subsequently, enforced expression of RASAL1 repressed significantly the gastric cancer cell transformation ability. These findings demonstrated that decreased RASAL1 expression is a characteristic of gastric cancer and regulated by epigenetic mechanisms. RASAL1 may be a functional tumor suppressor involved in gastric cancer. This study provides novel insights into the biological role of RASAL1 in gastric carcinogenesis.
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Affiliation(s)
- Fengchang Qiao
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, Institute of Life Science, and Department of Genetics and Developmental Biology, Medical School of Southeast University, Nanjing 210009, PR China
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Shi GX, Andres DA, Cai W. Ras family small GTPase-mediated neuroprotective signaling in stroke. Cent Nerv Syst Agents Med Chem 2012; 11:114-37. [PMID: 21521171 DOI: 10.2174/187152411796011349] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 01/18/2011] [Accepted: 03/22/2011] [Indexed: 12/31/2022]
Abstract
Selective neuronal cell death is one of the major causes of neuronal damage following stroke, and cerebral cells naturally mobilize diverse survival signaling pathways to protect against ischemia. Importantly, therapeutic strategies designed to improve endogenous anti-apoptotic signaling appear to hold great promise in stroke treatment. While a variety of complex mechanisms have been implicated in the pathogenesis of stroke, the overall mechanisms governing the balance between cell survival and death are not well-defined. Ras family small GTPases are activated following ischemic insults, and in turn, serve as intrinsic switches to regulate neuronal survival and regeneration. Their ability to integrate diverse intracellular signal transduction pathways makes them critical regulators and potential therapeutic targets for neuronal recovery after stroke. This article highlights the contribution of Ras family GTPases to neuroprotective signaling cascades, including mitogen-activated protein kinase (MAPK) family protein kinase- and AKT/PKB-dependent signaling pathways as well as the regulation of cAMP response element binding (CREB), Forkhead box O (FoxO) and hypoxiainducible factor 1(HIF1) transcription factors, in stroke.
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Affiliation(s)
- Geng-Xian Shi
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, 741 S. Limestone St., Lexington, KY 40536-0509, USA.
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Elvers M, Beck S, Fotinos A, Ziegler M, Gawaz M. The GRAF family member oligophrenin1 is a RhoGAP with BAR domain and regulates Rho GTPases in platelets. Cardiovasc Res 2012; 94:526-36. [DOI: 10.1093/cvr/cvs079] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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Abstract
Ever since their discovery as cellular counterparts of viral oncogenes more than 25 years ago, much progress has been made in understanding the complex networks of signal transduction pathways activated by oncogenic Ras mutations in human cancers. The activity of Ras is regulated by nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs), and much emphasis has been put into the biochemical and structural analysis of the Ras/GAP complex. The mechanisms by which GAPs catalyze Ras-GTP hydrolysis have been clarified and revealed that oncogenic Ras mutations confer resistance to GAPs and remain constitutively active. However, it is yet unclear how cells coordinate the large and divergent GAP protein family to promote Ras inactivation and ensure a certain biological response. Different domain arrangements in GAPs to create differential protein-protein and protein-lipid interactions are probably key factors determining the inactivation of the 3 Ras isoforms H-, K-, and N-Ras and their effector pathways. In recent years, in vitro as well as cell- and animal-based studies examining GAP activity, localization, interaction partners, and expression profiles have provided further insights into Ras inactivation and revealed characteristics of several GAPs to exert specific and distinct functions. This review aims to summarize knowledge on the cell biology of RasGAP proteins that potentially contributes to differential regulation of spatiotemporal Ras signaling.
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Affiliation(s)
- Thomas Grewal
- Faculty of Pharmacy, University of Sydney, Sydney, NSW, Australia
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Citi S, Spadaro D, Schneider Y, Stutz J, Pulimeno P. Regulation of small GTPases at epithelial cell-cell junctions. Mol Membr Biol 2011; 28:427-44. [DOI: 10.3109/09687688.2011.603101] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Xia TS, Chen H, Qian JZ, Xu HM, Lu FL. Clinical significance of expression of RASAL1 in gastric cancer. Shijie Huaren Xiaohua Zazhi 2011; 19:1403-1407. [DOI: 10.11569/wcjd.v19.i13.1403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To detect the expression of Ras protein activator like 1 (RASAL1) in gastric cancer and to analyze its clinicopathological significance.
METHODS: Immunohistochemistry was used to detect RASAL1 expression in 50 cases of normal gastric tissue, 50 cases of low intraepithelial neoplasia, 50 cases of high intraepithelial neoplasia and early gastric carcinoma, and 50 cases of advanced gastric carcinoma. The correlation between RASAL1 expression and clinicopathological features of gastric cancer was then analyzed.
RESULTS: The positive rate of RASAL1 expression had significant differences among each group. The positive rate of RASAL1 expression was 94.0% (47/50) in normal gastric tissue, 70.0% (35/50) in low intraepithelial neoplasia, 42.0% (21/50) in intraepithelial neoplasia and early gastric carcinoma, and 18.0% (9/50) in advanced gastric carcinoma. The positive rate of RASAL1 expression was not correlated with sex, age, or tumor site, but was correlated with tumor size, differentiation, invasive depth and lymph node metastasis in high intraepithelial neoplasia and early gastric carcinoma and advanced gastric carcinoma (all P < 0.05).
CONCLUSION: Decreased expression of RASAL1 correlates with the development of gastric cancer. The lower expression of RASAL1 underlies bigger tumor size, lower degree of differentiation, deeper invasion, and more metastatic lymph nodes in patients with gastric cancer.
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Zaidi SK, Young DW, Montecino M, van Wijnen AJ, Stein JL, Lian JB, Stein GS. Bookmarking the genome: maintenance of epigenetic information. J Biol Chem 2011; 286:18355-61. [PMID: 21454629 DOI: 10.1074/jbc.r110.197061] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mitotic inheritance of gene function is obligatory to sustain biological control. Emerging evidence suggests that epigenetic mechanisms are linked to transmission of cell fate, lineage commitment, and maintenance of cellular phenotype in progeny cells. Mechanisms of epigenetic memory include gene silencing by DNA methylation, transcriptional regulation by histone modifications, regulation of gene expression by noncoding small RNA molecules, and retention of regulatory machinery on target gene loci for activation and repression. We will focus on the regulatory implications of epigenetic memory for physiological control and for the onset and progression of disease.
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Affiliation(s)
- Sayyed K Zaidi
- Department of Cell Biology and Cancer Center, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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28
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Seto M, Ohta M, Ikenoue T, Sugimoto T, Asaoka Y, Tada M, Mohri D, Kudo Y, Ijichi H, Tateishi K, Otsuka M, Hirata Y, Maeda S, Koike K, Omata M. Reduced expression of RAS protein activator like-1 in gastric cancer. Int J Cancer 2011; 128:1293-302. [PMID: 20473946 DOI: 10.1002/ijc.25459] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
RAS signaling is frequently deregulated in human neoplasms. However, RAS mutations have been found in only a small proportion of human gastric cancers, implicating other mechanisms in the activation of RAS signaling in gastric tumorigenesis. We have previously reported that decreased expression of RAS protein activator like-1 (RASAL1), a member of the RAS-GTPase-activating proteins that switch off RAS activity, contributes to colon tumor progression. In our study, we explored the involvement of decreased RASAL1 expression in gastric tumorigenesis. RASAL1 expression was reduced in 6 of 10 gastric cancer cell lines examined by immunoblotting. Knockdown of RASAL1 increased mitogen-activated protein kinase signaling in response to growth factor stimulation, and the forced expression of RASAL1 reduced proliferation of gastric cancer cells. Immunohistochemical analyses in primary gastric tumors showed that RASAL1 expression was reduced in 23 of 48 (48%) of the gastric cancers but in none of the adenomas (0/10). Methylation of the RASAL1 promoter region and loss of heterozygosity (LOH) at the RASAL1 locus were examined to investigate the causes of RASAL1 silencing. All cell lines with reduced RASAL1 had RASAL1 methylation, and two had LOH. In primary gastric cancers, methylation or LOH was detected in 50% (6/12) of those with reduced RASAL1. Furthermore, RASAL1 expression was restored in some cell lines by histone deacetylase inhibitor treatment. Our findings demonstrate that reduced RASAL1 expression, partly due to genetic and epigenetic changes, contributes to gastric carcinogenesis, and also re-emphasize the importance of RAS signaling in gastric cancer development.
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Affiliation(s)
- Motoko Seto
- Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
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Calvisi DF, Ladu S, Conner EA, Seo D, Hsieh JT, Factor VM, Thorgeirsson SS. Inactivation of Ras GTPase-activating proteins promotes unrestrained activity of wild-type Ras in human liver cancer. J Hepatol 2011; 54:311-9. [PMID: 21067840 PMCID: PMC3031080 DOI: 10.1016/j.jhep.2010.06.036] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 06/01/2010] [Accepted: 06/22/2010] [Indexed: 12/15/2022]
Abstract
BACKGROUND & AIMS Aberrant activation of the RAS pathway is ubiquitous in human hepatocarcinogenesis, but the molecular mechanisms leading to RAS induction in the absence of RAS mutations remain under-investigated. We defined the role of Ras GTPase activating proteins (GAPs) in the constitutive activity of Ras signaling during human hepatocarcinogenesis. METHODS The mutation status of RAS genes and RAS effectors was assessed in a collection of human hepatocellular carcinomas (HCC). Levels of RAS GAPs (RASA1-4, RASAL1, nGAP, SYNGAP1, DAB2IP, and NF1) and the RASAL1 upstream inducer PITX1 were determined by real-time RT-PCR and immunoblotting. The promoter and genomic status of RASAL1, DAB2IP, NF1, and PITX1 were assessed by methylation assays and microsatellite analysis. Effects of RASAL1, DAB2IP, and PITX1 on HCC growth were evaluated by transfection and siRNA analyses of HCC cell lines. RESULTS In the absence of Ras mutations, downregulation of at least one RAS GAP (RASAL1, DAB2IP, or NF1) was found in all HCC samples. Low levels of DAB2IP and PITX1 were detected mostly in a HCC subclass from patients with poor survival, indicating that these proteins control tumor aggressiveness. In HCC cells, reactivation of RASAL1, DAB2IP, and PITX1 inhibited proliferation and induced apoptosis, whereas their silencing increased proliferation and resistance to apoptosis. CONCLUSIONS Selective suppression of RASAL1, DAB2IP, or NF1 RAS GAPs results in unrestrained activation of Ras signaling in the presence of wild-type RAS in HCC.
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Affiliation(s)
- Diego F. Calvisi
- Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4262, USA
- Department of Biomedical Sciences, Experimental Pathology and Oncology Section, University of Sassari, Italy
| | - Sara Ladu
- Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4262, USA
| | - Elizabeth A. Conner
- Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4262, USA
| | - Daekwan Seo
- Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4262, USA
| | - Jer-Tsong Hsieh
- Department of Urology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Valentina M. Factor
- Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4262, USA
| | - Snorri S. Thorgeirsson
- Laboratory of Experimental Carcinogenesis, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4262, USA
- Correspondence: Dr. Snorri S. Thorgeirsson, National Cancer Institute, Building 37, Room 4146A, 37 Convent Drive MSC 4262, Bethesda, MD 20892-4262; Telephone: (301) 496-1935; Fax: (301) 496-0734;
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Shilyansky C, Lee YS, Silva AJ. Molecular and cellular mechanisms of learning disabilities: a focus on NF1. Annu Rev Neurosci 2011; 33:221-43. [PMID: 20345245 DOI: 10.1146/annurev-neuro-060909-153215] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Neurofibromatosis Type I (NF1) is a single-gene disorder characterized by a high incidence of complex cognitive symptoms, including learning disabilities, attention deficit disorder, executive function deficits, and motor coordination problems. Because the underlying genetic cause of this disorder is known, study of NF1 from a molecular, cellular, and systems perspective has provided mechanistic insights into the etiology of higher-order cognitive symptoms associated with the disease. In particular, studies of animal models of NF1 indicated that disruption of Ras regulation of inhibitory networks is critical to the etiology of cognitive deficits associated with NF1. Animal models of Nf1 identified mechanisms and pathways that are required for cognition, and represent an important complement to the complex neuropsychological literature on learning disabilities associated with this condition. Here, we review findings from NF1 animal models and human populations affected by NF1, highlighting areas of potential translation and discussing the implications and limitations of generalizing findings from this single-gene disease to idiopathic learning disabilities.
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Affiliation(s)
- C Shilyansky
- Department of Neurobiology, Psychology, Psychiatry and Biobehavioral Sciences, Semel Institute, University of California, Los Angeles, California 90095, USA
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31
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Zhou YT, Chew LL, Lin SC, Low BC. The BNIP-2 and Cdc42GAP homology (BCH) domain of p50RhoGAP/Cdc42GAP sequesters RhoA from inactivation by the adjacent GTPase-activating protein domain. Mol Biol Cell 2010; 21:3232-46. [PMID: 20660160 PMCID: PMC2938388 DOI: 10.1091/mbc.e09-05-0408] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The BNIP-2 and Cdc42GAP Homology (BCH) domain from p50RhoGAP sequesters RhoA from inactivation by the adjacent GAP domain and it confers unique Rho-binding profile from that of GAP domain. This suppression is further augmented by an intramolecular interaction, adding to a new paradigm for regulating p50RhoGAP signaling. The BNIP-2 and Cdc42GAP homology (BCH) domain is a novel regulator for Rho GTPases, but its impact on p50-Rho GTPase-activating protein (p50RhoGAP or Cdc42GAP) in cells remains elusive. Here we show that deletion of the BCH domain from p50RhoGAP enhanced its GAP activity and caused drastic cell rounding. Introducing constitutively active RhoA or inactivating GAP domain blocked such effect, whereas replacing the BCH domain with endosome-targeting SNX3 excluded requirement of endosomal localization in regulating the GAP activity. Substitution with homologous BCH domain from Schizosaccharomyces pombe, which does not bind mammalian RhoA, also led to complete loss of suppression. Interestingly, the p50RhoGAP BCH domain only targeted RhoA, but not Cdc42 or Rac1, and it was unable to distinguish between GDP and the GTP-bound form of RhoA. Further mutagenesis revealed a RhoA-binding motif (residues 85-120), which when deleted, significantly reduced BCH inhibition on GAP-mediated cell rounding, whereas its full suppression also required an intramolecular interaction motif (residues 169-197). Therefore, BCH domain serves as a local modulator in cis to sequester RhoA from inactivation by the adjacent GAP domain, adding to a new paradigm for regulating p50RhoGAP signaling.
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Affiliation(s)
- Yi Ting Zhou
- Cell Signaling and Developmental Biology Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117543, Republic of Singapore.
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32
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The anaphase-promoting complex/cyclosome activator Cdh1 modulates Rho GTPase by targeting p190 RhoGAP for degradation. Mol Cell Biol 2010; 30:3994-4005. [PMID: 20530197 DOI: 10.1128/mcb.01358-09] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cdh1 is an activator of the anaphase-promoting complex/cyclosome and contributes to mitotic exit and G(1) maintenance by targeting cell cycle proteins for degradation. However, Cdh1 is expressed and active in postmitotic or quiescent cells, suggesting that it has functions other than cell cycle control. Here, we found that homozygous Cdh1 gene-trapped (Cdh1(GT/GT)) mouse embryonic fibroblasts (MEFs) and Cdh1-depleted HeLa cells reduced stress fiber formation significantly. The GTP-bound active Rho protein was apparently decreased in the Cdh1-depleted cells. The p190 protein, a major GTPase-activating protein for Rho, accumulated both in Cdh1(GT/GT) MEFs and in Cdh1-knockdown HeLa cells. Cdh1 formed a physical complex with p190 and stimulated the efficient ubiquitination of p190, both in in vitro and in vivo. The motility of Cdh1-depleted HeLa cells was impaired; however, codepletion of p190 rescued the migration activity of these cells. Moreover, Cdh1(GT/GT) embryos exhibited phenotypes similar to those observed for Rho-associated kinase I and II knockout mice: eyelid closure delay and disruptive architecture with frequent thrombus formation in the placental labyrinth layer, respectively. Furthermore, the p190 protein accumulated in the Cdh1(GT/GT) embryonic tissues. Our data revealed a novel function for Cdh1 as a regulator of Rho and provided insights into the role of Cdh1 in cell cytoskeleton organization and cell motility.
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33
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Terry S, Nie M, Matter K, Balda MS. Rho signaling and tight junction functions. Physiology (Bethesda) 2010; 25:16-26. [PMID: 20134025 DOI: 10.1152/physiol.00034.2009] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tight junctions are heteromeric protein complexes that act as signaling centers by mediating the bidirectional transmission of information between the environment and the cell interior to control paracellular permeability and differentiation. Insight into tight junction-associated signaling mechanisms is of fundamental importance for our understanding of the physiology of epithelia and endothelia in health and disease.
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Affiliation(s)
- Steve Terry
- Department of Cell Biology, UCL Institute of Ophthalmology, University College London, London, United Kingdom
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Min J, Zaslavsky A, Fedele G, McLaughlin SK, Reczek EE, De Raedt T, Guney I, Strochlic DE, Laura E, Beroukhim R, Bronson RT, Ryeom S, Hahn WC, Loda M, Cichowski K. An oncogene-tumor suppressor cascade drives metastatic prostate cancer by coordinately activating Ras and nuclear factor-kappaB. Nat Med 2010; 16:286-94. [PMID: 20154697 PMCID: PMC2903662 DOI: 10.1038/nm.2100] [Citation(s) in RCA: 310] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 01/15/2010] [Indexed: 12/17/2022]
Abstract
Metastasis is responsible for the majority of prostate cancer-related deaths; however, little is known about the molecular mechanisms that underlie this process. Here we identify an oncogene-tumor suppressor cascade that promotes prostate cancer growth and metastasis by coordinately activating the small GTPase Ras and nuclear factor-kappaB (NF-kappaB). Specifically, we show that loss of the Ras GTPase-activating protein (RasGAP) gene DAB2IP induces metastatic prostate cancer in an orthotopic mouse tumor model. Notably, DAB2IP functions as a signaling scaffold that coordinately regulates Ras and NF-kappaB through distinct domains to promote tumor growth and metastasis, respectively. DAB2IP is suppressed in human prostate cancer, where its expression inversely correlates with tumor grade and predicts prognosis. Moreover, we report that epigenetic silencing of DAB2IP is a key mechanism by which the polycomb-group protein histone-lysine N-methyltransferase EZH2 activates Ras and NF-kappaB and triggers metastasis. These studies define the mechanism by which two major pathways can be simultaneously activated in metastatic prostate cancer and establish EZH2 as a driver of metastasis.
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Affiliation(s)
- Junxia Min
- Genetics Division, Department of Medicine, Boston, MA, 02115, USA
- Brigham and Women’s Hospital, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
| | - Alexander Zaslavsky
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia PA 19104
| | - Giuseppe Fedele
- Harvard Medical School, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - Sara K. McLaughlin
- Genetics Division, Department of Medicine, Boston, MA, 02115, USA
- Brigham and Women’s Hospital, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
| | - Elizabeth E. Reczek
- Genetics Division, Department of Medicine, Boston, MA, 02115, USA
- Brigham and Women’s Hospital, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
| | - Thomas De Raedt
- Genetics Division, Department of Medicine, Boston, MA, 02115, USA
- Brigham and Women’s Hospital, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
| | - Isil Guney
- Harvard Medical School, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - David E. Strochlic
- Harvard Medical School, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - E. Laura
- Broad Institute of Harvard and MIT, Cambridge, MA 02142
- Ludwig Center at Dana-Farber/Harvard Cancer Center, Boston, MA 02115
| | - Rameen Beroukhim
- Brigham and Women’s Hospital, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
- Ludwig Center at Dana-Farber/Harvard Cancer Center, Boston, MA 02115
| | | | - Sandra Ryeom
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia PA 19104
| | - William C. Hahn
- Brigham and Women’s Hospital, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
- Ludwig Center at Dana-Farber/Harvard Cancer Center, Boston, MA 02115
| | - Massimo Loda
- Harvard Medical School, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
| | - Karen Cichowski
- Genetics Division, Department of Medicine, Boston, MA, 02115, USA
- Brigham and Women’s Hospital, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, 02115, USA
- Ludwig Center at Dana-Farber/Harvard Cancer Center, Boston, MA 02115
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35
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Yi SJ, Groffen J, Heisterkamp N. Transglutaminase 2 regulates the GTPase-activating activity of Bcr. J Biol Chem 2010; 284:35645-51. [PMID: 19840940 DOI: 10.1074/jbc.m109.062240] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Transglutaminase 2 (TG2) is a multifunctional protein that has been implicated in numerous pathologies including that of neurodegeneration and celiac disease, but the molecular interactions that mediate its diverse activities are largely unknown. Bcr and the closely related Abr negatively regulate the small G-protein Rac: loss of their combined function in vivo results in increased reactivity of innate immune cells. Bcr and Abr are GTPase-activating proteins that catalyze the hydrolysis of the GTP bound to Rac. However, how the Bcr and Abr GTPase-activating activity is regulated is not precisely understood. We here report a novel mechanism of regulation through direct protein-protein interaction with TG2. TG2 bound to the Rac-binding pocket in the GTPase-activating domains of Bcr and Abr, blocked Bcr activity and, through this mechanism, increased levels of active GTP-bound Rac and EGF-stimulated membrane ruffling. TG2 exists in at least two different conformations. Interestingly, experiments using TG2 mutants showed that Bcr exhibits preferential binding to the non-compacted conformation of TG2, in which its catalytic domain is exposed, but transamidation is not needed for the interaction. Thus, TG2 regulates levels of cellular GTP-bound Rac and actin cytoskeletal reorganization through a new mechanism involving direct inhibition of Bcr GTPase-activating activity.
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Affiliation(s)
- Sun-Ju Yi
- Section of Molecular Carcinogenesis, Division of Hematology/Oncology, Childrens Hospital Los Angeles and the Saban Research Institute of Childrens Hospital, Los Angeles, California 90027, USA
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36
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Grinnell KL, Casserly B, Harrington EO. Role of protein tyrosine phosphatase SHP2 in barrier function of pulmonary endothelium. Am J Physiol Lung Cell Mol Physiol 2009; 298:L361-70. [PMID: 20023173 DOI: 10.1152/ajplung.00374.2009] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Pulmonary edema is mediated in part by disruption of interendothelial cell contacts. Protein tyrosine phosphatases (PTP) have been shown to affect both cell-extracellular matrix and cell-cell junctions. The SH2 domain-containing nonreceptor PTP, SHP2, is involved in intercellular signaling through direct interaction with adherens junction proteins. In this study, we examined the role of SHP2 in pulmonary endothelial barrier function. Inhibition of SHP2 promoted edema formation in rat lungs and increased monolayer permeability in cultured lung endothelial cells. In addition, pulmonary endothelial cells demonstrated a decreased level of p190RhoGAP activity following inhibition of SHP2, events that were accompanied by a concomitant increase in RhoA activity. Furthermore, immunofluorescence microscopy confirmed enhanced actin stress fiber formation and diminished interendothelial staining of adherens junction complex-associated proteins upon SHP2 inhibition. Finally, immunoprecipitation and immunoblot analyses demonstrated increased tyrosine phosphorylation of VE-cadherin, beta-catenin, and p190RhoGAP proteins, as well as decreased association between p120-catenin and VE-cadherin proteins. Our findings suggest that SHP2 supports basal pulmonary endothelial barrier function by coordinating the tyrosine phosphorylation profile of VE-cadherin, beta-catenin, and p190RhoGAP and the activity of RhoA, signaling molecules important in adherens junction complex integrity.
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Affiliation(s)
- K L Grinnell
- Vascular Research Laboratory, Providence VA Medical Center, 830 Chalkstone Ave., Providence, RI 02908, USA
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Erlmann P, Schmid S, Horenkamp FA, Geyer M, Pomorski TG, Olayioye MA. DLC1 activation requires lipid interaction through a polybasic region preceding the RhoGAP domain. Mol Biol Cell 2009; 20:4400-11. [PMID: 19710422 DOI: 10.1091/mbc.e09-03-0247] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Deleted in Liver Cancer 1 (DLC1) is a GTPase-activating protein (GAP) with specificity for RhoA, RhoB, and RhoC that is frequently deleted in various tumor types. By inactivating these small GTPases, DLC1 controls actin cytoskeletal remodeling and biological processes such as cell migration and proliferation. Here we provide evidence that DLC1 binds to phosphatidylinositol-4,5-bisphosphate (PI(4,5)P(2)) through a previously unrecognized polybasic region (PBR) adjacent to its RhoGAP domain. Importantly, PI(4,5)P(2)-containing membranes are shown to stimulate DLC1 GAP activity in vitro. In living cells, a DLC1 mutant lacking an intact PBR inactivated Rho signaling less efficiently and was severely compromised in suppressing cell spreading, directed migration, and proliferation. We therefore propose that PI(4,5)P(2) is an important cofactor in DLC1 regulation in vivo and that the PBR is essential for the cellular functions of the protein.
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Affiliation(s)
- Patrik Erlmann
- Institute of Cell Biology and Immunology, University of Stuttgart, 70569 Stuttgart, Germany
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38
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Bernards A, Settleman J. Loss of the Ras regulator RASAL1: another route to Ras activation in colorectal cancer. Gastroenterology 2009; 136:46-8. [PMID: 19041648 DOI: 10.1053/j.gastro.2008.11.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Scholz RP, Regner J, Theil A, Erlmann P, Holeiter G, Jähne R, Schmid S, Hausser A, Olayioye MA. DLC1 interacts with 14-3-3 proteins to inhibit RhoGAP activity and block nucleocytoplasmic shuttling. J Cell Sci 2008; 122:92-102. [PMID: 19066281 DOI: 10.1242/jcs.036251] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Deleted in liver cancer 1 (DLC1) is a Rho-GTPase-activating protein (GAP) that is downregulated in various tumor types. In vitro, DLC1 specifically inactivates the small GTPases RhoA, RhoB and RhoC through its GAP domain and this appears to contribute to its tumor suppressor function in vivo. Molecular mechanisms that control DLC1 activity have not so far been investigated. Here, we show that phorbol-ester-induced activation of protein kinase C and protein kinase D stimulates association of DLC1 with the phosphoserine/phosphothreonine-binding 14-3-3 adaptor proteins via recognition motifs that involve Ser327 and Ser431. Association with 14-3-3 proteins inhibits DLC1 GAP activity and facilitates signaling by active Rho. We further show that treatment of cells with phorbol ester or coexpression of 14-3-3 proteins, blocks DLC1 nucleocytoplasmic shuttling, probably by masking a previously unrecognized nuclear localization sequence. The binding to 14-3-3 proteins is thus a newly discovered mechanism by which DLC1 activity is regulated and compartmentalized.
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Affiliation(s)
- Rolf-Peter Scholz
- University of Stuttgart, Institute of Cell Biology and Immunology, Allmandring 31, 70569 Stuttgart, Germany
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40
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Shen CH, Chen HY, Lin MS, Li FY, Chang CC, Kuo ML, Settleman J, Chen RH. Breast tumor kinase phosphorylates p190RhoGAP to regulate rho and ras and promote breast carcinoma growth, migration, and invasion. Cancer Res 2008; 68:7779-87. [PMID: 18829532 DOI: 10.1158/0008-5472.can-08-0997] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Breast tumor kinase (Brk), an Src-like nonreceptor tyrosine kinase, is overexpressed in breast cancer and several other cancer types. Our previous study indicates that Brk promotes cell migration and tumor invasion by phosphorylating the focal adhesion protein paxillin. Here, we report the identification of p190RhoGAP-A (p190) as a Brk substrate. Brk phosphorylates p190 at the Y(1105) residue both in vitro and in vivo, thereby promoting the association of p190 with p120RasGAP (p120). As a consequence, Brk stimulates p190 and attenuates p120 functions, leading to RhoA inactivation and Ras activation, respectively. In carcinoma cells expressing high levels of Brk, endogenous Brk functions as a key contributor to epidermal growth factor-induced p190 tyrosine phosphorylation. We present evidence showing that p190 phosphorylation plays essential roles in both migratory and proliferative effects of Brk. Furthermore, disruption of p190 phosphorylation-induced p190/p120 complex in breast cancer cells abolishes not only the abilities of Brk to regulate RhoA and Ras but also the stimulatory effects of Brk on proliferation, migration, invasion, transformation, and tumorigenicity. Together, our findings reveal a previously unknown function of Brk in regulating both RhoA and Ras by phosphorylating p190 and provide evidence for the crucial roles of this Brk-elicited signaling pathway in promoting breast malignancy.
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Affiliation(s)
- Che-Hung Shen
- Institute of Molecular Medicine, Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
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Shemarova IV, Nesterov VP. Evolution of mechanisms of Ca2+-signaling. Role of Ca2+ in regulation of fundamental cell functions. J EVOL BIOCHEM PHYS+ 2008. [DOI: 10.1134/s0022093008040017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Vilá de Muga S, Timpson P, Cubells L, Evans R, Hayes TE, Rentero C, Hegemann A, Reverter M, Leschner J, Pol A, Tebar F, Daly RJ, Enrich C, Grewal T. Annexin A6 inhibits Ras signalling in breast cancer cells. Oncogene 2008; 28:363-77. [PMID: 18850003 DOI: 10.1038/onc.2008.386] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Overexpression of epidermal growth factor receptor (EGFR) is associated with enhanced activation of wild-type (hyperactive) Ras in breast cancer. Little is known about the regulation of Ras inactivation and GTPase-activating proteins (GAPs), such as p120GAP, in cells with hyperactive Ras. Recently, we showed that in EGFR-overexpressing A431 cells, which lack endogenous Annexin A6 (AnxA6), ectopic expression of AnxA6 stimulates membrane recruitment of p120GAP to modulate Ras signalling. We now demonstrate that, AnxA6 is downregulated in a number of EGFR-overexpressing and estrogen receptor (ER)-negative breast cancer cells. In these cells, AnxA6 overexpression promotes Ca(2+)- and EGF-inducible membrane targeting of p120GAP. In ER-negative MDA-MB-436 cells, overexpression of p120GAP, but not CAPRI or a p120GAP mutant lacking the AnxA6-binding domain inhibits Ras/MAPK activity. AnxA6 knockdown in MDA-MB-436 increases Ras activity and cell proliferation in anchorage-independent growth assays. Furthermore, AnxA6 co-immunoprecipitates with H-Ras in a Ca(2+)- and EGF-inducible manner and fluorescence resonance energy transfer (FRET) microscopy confirmed that AnxA6 is in close proximity of active (G12V), but not inactive (S17N) H-Ras. Thus, association of AnxA6 with H-Ras-containing protein complexes may contribute to regulate p120GAP/Ras assembly in EGFR-overexpressing and ER-negative breast cancer cells.
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Affiliation(s)
- S Vilá de Muga
- Departament de Biologia Cellular, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain
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Raepple D, von Lintig F, Zemojtel T, Duchniewicz M, Jung A, Lübbert M, Boss GR, Scheele JS. Determination of Ras-GTP and Ras-GDP in patients with acute myelogenous leukemia (AML), myeloproliferative syndrome (MPS), juvenile myelomonocytic leukemia (JMML), acute lymphocytic leukemia (ALL), and malignant lymphoma: assessment of mutational and indirect activation. Ann Hematol 2008; 88:319-24. [PMID: 18784923 PMCID: PMC2755762 DOI: 10.1007/s00277-008-0593-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2008] [Accepted: 08/05/2008] [Indexed: 11/30/2022]
Abstract
The 21-kD protein Ras of the low-molecular-weight GTP-binding (LMWG) family plays an important role in transduction of extracellular signals. Ras functions as a ‘molecular switch’ in transduction of signals from the membrane receptors of many growth factors, cytokines, and other second messengers to the cell nucleus. Numerous studies have shown that in multiple malignant tumors and hematopoietic malignancies, faulty signal transduction via the Ras pathway plays a key role in tumorigenesis. In this work, a non-radioactive assay was used to quantify Ras activity in hematologic malignancies. Ras activation was measured in six different cell lines and 24 patient samples, and sequence analysis of N- and K-ras was performed. The 24 patient samples comprised of seven acute myelogenous leukemia (AML) samples, five acute lymphocytic leukemia (ALL) samples, four myeloproliferative disease (MPD) samples, four lymphoma samples, four juvenile myelomonocytic leukemia (JMML) samples, and WBC from a healthy donor. The purpose of this study was to compare Ras activity determined by percentage of Ras-GTP with the mutational status of the Ras gene in the hematopoietic cells of the patients. Mutation analysis revealed ras mutations in two of the seven AML samples, one in codon 12 and one in codon 61; ras mutations were also found in two of the four JMML samples, and in one of the four lymphoma samples (codon 12). We found a mean Ras activation of 23.1% in cell lines with known constitutively activating ras mutations, which was significantly different from cell lines with ras wildtype sequence (Ras activation of 4.8%). Two of the five activating ras mutations in the patient samples correlated with increased Ras activation. In the other three samples, Ras was probably activated through “upstream” or “downstream” mechanisms.
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Affiliation(s)
- D Raepple
- Department of Medicine I, University of Freiburg Medical Center, Hugstetter Str. 55, 79106 Freiburg, Germany
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Tissue-specific functions of the Caenorhabditis elegans p120 Ras GTPase activating protein GAP-3. Dev Biol 2008; 323:166-76. [PMID: 18805410 DOI: 10.1016/j.ydbio.2008.08.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 08/26/2008] [Accepted: 08/27/2008] [Indexed: 02/01/2023]
Abstract
All metazoan genomes encode multiple RAS GTPase activating proteins (RasGAPs) that negatively regulate the conserved RAS/MAPK signaling pathway. In mammals, several RasGAPs exhibit tumor suppressor activity by preventing excess RAS signal transduction. We have identified gap-3 as the to date missing Caenorhabditiselegans member of the p120 RasGAP family. By studying the genetic interaction of gap-3 with the two previously identified RasGAPs gap-1 and gap-2, we find that different combinations of RasGAPs are used to repress LET-60 RAS signaling depending on the cellular context. GAP-3 is the predominant negative regulator of RAS during meiotic progression of the germ cells, while GAP-1 is the key inhibitor of RAS during vulval induction. In other tissues such as the sex myoblasts or the chemosensory neurons, all three RasGAPs act in concert. The C. elegans RasGAPs have thus undergone partial specialization after gene duplication to allow the differential regulation of the RAS/MAPK signaling pathway in different cell types. A similar tissue specialization of the human tumor suppressor genes may explain the strong bias in the type of cancer they promote when mutated.
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Nowicki M, Kosacka J, Brossmer R, Spanel-Borowski K, Borlak J. The myelin-associated glycoprotein inhibitor BENZ induces outgrowth and survival of rat dorsal root ganglion cell cultures. J Neurosci Res 2008; 85:3053-63. [PMID: 17722062 DOI: 10.1002/jnr.21422] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The novel myelin-associated glycoprotein (MAG) inhibitor BENZ binds to the N-acetylneuraminic acid (Neu5Ac) portion of the N-terminal Ig-like domain of MAG. Treatment of rat dorsal root ganglion (DRG) cell cultures with BENZ-induced outgrowth of neurofilament 200-positive neurites improved survival of neurons and increased the number of GFAP-positive cells, as determined by fluorescence and confocal laser microscopy and by Western immunoblotting. Furthermore, treatment of DRG cell cultures with BENZ repressed gene and protein expression of the small GTPase RhoA but induced expression of Rho GTP-activating proteins 5 and 24, likely to counteract protein kinase A activity. Specifically, expression of inhibitors of neurite outgrowth, for example, Rock2 and PAK4, was repressed, but cofilin 1, a promoter of axonal growth, was induced. We propose that the MAG inhibitor BENZ abrogates the RhoA-ROCK-cofilin pathway to promote neurite outgrowth. Our findings require confirmation by in vivo animal studies.
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Affiliation(s)
- Marcin Nowicki
- University of Leipzig, Institute of Anatomy, Leipzig, Germany
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Roscioni SS, Elzinga CRS, Schmidt M. Epac: effectors and biological functions. Naunyn Schmiedebergs Arch Pharmacol 2008; 377:345-57. [PMID: 18176800 DOI: 10.1007/s00210-007-0246-7] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Accepted: 12/05/2007] [Indexed: 12/17/2022]
Abstract
Epac1 (also known as cAMP-GEF-I) and Epac2 (also known as cAMP-GEF-II) are cyclic AMP-activated guanine nucleotide exchange factors for Ras-like GTPases. Since their discovery about 10 years ago, it is now accepted that Epac proteins are novel cAMP sensors that regulate several pivotal cellular processes, including calcium handling, cell proliferation, cell survival, cell differentiation, cell polarization, cell-cell adhesion events, gene transcription, secretion, ion transport, and neuronal signaling. Recent studies even indicated that Epac proteins might play a role in the regulation of inflammation and the development of cardiac hypertrophy. Meanwhile, a plethora of diverse effectors of Epac proteins have been assigned, such as Ras and Rho GTPases, phospholiase C-epsilon, phospholipase D, mitogen-activated protein kinases, protein kinase B/Akt, ion channels, secretory-granule associated proteins and regulators of the actin-microtubule network, the latter probably involved in the spatiotemporal dynamics of Epac-related signaling. This review highlights multi-faceted effectors and diverse biological functions driven by Epac proteins that might explain certain controversial signaling properties of cAMP.
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Affiliation(s)
- Sara S Roscioni
- Department of Molecular Pharmacology, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
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Abstract
The intracellular trafficking of numerous proteins requires a tight control to fulfil their physiological functions. It is the case of the adipocyte and muscle glucose transporter Glut4 that is retained intracellularly until insulin induces its recruitment to the plasma membrane. Rabs are evolutionarily conserved small GTPases that control intracellular traffic events from yeast to mammalian cells. In the past few decades, considerable progresses have been made in identifying the route of Glut4, the Rabs involved in controlling it, and more recently the connection between insulin signalling and Glut4 trafficking through Rab activity control.
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Affiliation(s)
- V Kaddai
- Institut National de la Santé et de la Recherche Médicale INSERM U568 Faculté de Médecine, Université de Nice-Sophia Antipolis, Nice Cedex, France
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Hamadmad SN, Hohl RJ. Erythropoietin stimulates cancer cell migration and activates RhoA protein through a mitogen-activated protein kinase/extracellular signal-regulated kinase-dependent mechanism. J Pharmacol Exp Ther 2007; 324:1227-33. [PMID: 18079357 DOI: 10.1124/jpet.107.129643] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Erythropoietin (Epo) receptor (EpoR) is expressed in several cancer cell lines, and the functional consequence of this expression is under extensive study. In this study, we used a cervical cancer cell line in which EpoR was first found to be expressed and to correlate with the severity of the disease. We demonstrate that Epo is a chemoattractant for these cancer cells, enhancing their migration under serum-starved conditions. Using a Transwell migration system, we show that Epo enhances cancer cell migration in a dose- and time-dependent manner. The effect of Epo is dependent on the activity of two signaling pathways: the mitogen-activated protein kinase (MAPK) pathway and the RhoA GTPase pathway. We show that Epo activates both pathways in a Janus kinase-dependent manner and that this activation is required for Epo effects on cell migration. Furthermore, we use both pharmacological and genetic inhibitors to demonstrate that the activation of RhoA GTPase is dependent on the activity of the MAPK pathway, providing the first evidence for interaction between these two signaling cascades.
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Affiliation(s)
- Sumaya N Hamadmad
- Department of Internal Medicine, SE 313 GH, University of Iowa, Iowa City, IA 52242, USA
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Branco J, Al-Ramahi I, Ukani L, Pérez AM, Fernandez-Funez P, Rincón-Limas D, Botas J. Comparative analysis of genetic modifiers in Drosophila points to common and distinct mechanisms of pathogenesis among polyglutamine diseases. Hum Mol Genet 2007; 17:376-90. [PMID: 17984172 DOI: 10.1093/hmg/ddm315] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Spinocerebellar Ataxia type 1 (SCA1) and Huntington's disease (HD) are two polyglutamine disorders caused by expansion of a CAG repeat within the coding regions of the Ataxin-1 and Huntingtin proteins, respectively. While protein folding and turnover have been implicated in polyglutamine disorders in general, many clinical and pathological differences suggest that there are also disease-specific mechanisms. Taking advantage of a collection of genetic modifiers of expanded Ataxin-1-induced neurotoxicity, we performed a comparative analysis in Drosophila models of the two diseases. We show that while some modifier genes function similarly in SCA1 and HD Drosophila models, others have model-specific effects. Surprisingly, certain modifier genes modify SCA1 and HD models in opposite directions, i.e. they behave as suppressors in one case and enhancers in the other. Furthermore, we find that modulation of toxicity does not correlate with alterations in the formation of neuronal intranuclear inclusions. Our results point to potential common therapeutic targets in novel pathways, and to genes and pathways responsible for differences between Ataxin-1 and Huntingtin-induced neurodegeneration.
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Affiliation(s)
- Joana Branco
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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