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Sun D, Guo Y, Tang P, Li H, Chen L. Arf6 as a therapeutic target: Structure, mechanism, and inhibitors. Acta Pharm Sin B 2023; 13:4089-4104. [PMID: 37799386 PMCID: PMC10547916 DOI: 10.1016/j.apsb.2023.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/28/2023] [Accepted: 06/02/2023] [Indexed: 10/07/2023] Open
Abstract
ADP-ribosylation factor 6 (Arf6), a small G-protein of the Ras superfamily, plays pivotal roles in multiple cellular events, including exocytosis, endocytosis, actin remodeling, plasma membrane reorganization and vesicular transport. Arf6 regulates the progression of cancer through the activation of cell motility and invasion. Aberrant Arf6 activation is a potential therapeutic target. This review aims to understand the comprehensive function of Arf6 for future cancer therapy. The Arf6 GEFs, protein structure, and roles in cancer have been summarized. Comprehending the mechanism underlying Arf6-mediated cancer cell growth and survival is essential. The structural features of Arf6 and its efforts are discussed and may be contributed to the discovery of future novel protein-protein interaction inhibitors. In addition, Arf6 inhibitors and mechanism of action are listed in the table. This review further emphasizes the crucial roles in drug resistance and attempts to offer an outlook of Arf6 in cancer therapy.
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Affiliation(s)
- Dejuan Sun
- Wuya College of Innovation, Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Yuanyuan Guo
- Wuya College of Innovation, Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Piyu Tang
- Wuya College of Innovation, Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Hua Li
- Wuya College of Innovation, Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
- College of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou 350122, China
| | - Lixia Chen
- Wuya College of Innovation, Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang 110016, China
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2
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Qin G, Zhao Y, Gan Y, Yu X, Zhao Y, Peng H, Fang S. Alterations in gene expressions of Caco-2 cell responses to LPS and ploy(I:C) stimulation. PeerJ 2023; 11:e15459. [PMID: 37304876 PMCID: PMC10257391 DOI: 10.7717/peerj.15459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 05/03/2023] [Indexed: 06/13/2023] Open
Abstract
The intestinal epithelium barrier serves as a highly dynamic immunologic frontier in the defense against invading pathogenic bacteria and viruses. Hence, understanding of the complicated underlying relationship between enteric pathogens and the intestinal epithelium barrier is vital for developing strategies to improve the intestinal health of farm animals. To this end, Caco-2 cells were stimulated by 1 µg/ml lipopolysaccharide (LPS) for 24 h and 5 µg/ml polyinosinic-polycytidylic acid (ploy(I:C)) for 4 h to imitate bacterial and viral infection processes, respectively. The specific alterations in gene expression of Caco-2 cells after stimulation were characterized by transcriptome sequencing. Seventy differentially expressed genes (DEGs) were identified under LPS exposure, and 17 DEGs were observed under ploy(I:C) exposure. We found that most DEGs were specific, and only one common DEG SPAG7 was observed. Gene Ontology (GO) annotation analysis indicated that all DEGs identified in the different treatments were mainly derived from GO terms related to the maintenance of cellular homeostasis. Moreover, specific DEGs such as SLC39A10, MT2A, and MT1E regulated by LPS treatment, while IFIT2 and RUNX2 mediated by ploy(I:C) treatment, which are derived from immune function modulation related GO terms, were confirmed by both transcriptome sequencing and qRT-PCR. In addition, both transcriptome sequencing and qRT-PCR results verified that LPS specifically down-regulated the DEGs INHBE and ARF6, which are involved in inflammation responses related to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway including the TGF-beta signaling pathways and the Ras signaling pathway. Ploy(I:C) uniquely suppressed the DEGs GABARAP and LAMTOR3, which participated in viral replication-associated pathways including autophagy and mTOR signaling pathway.
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Affiliation(s)
- Ge Qin
- Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yuanjie Zhao
- Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yating Gan
- Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiaomei Yu
- Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yifan Zhao
- Fujian Agriculture and Forestry University, Fuzhou, China
| | - Hui Peng
- Hainan University, Haikou, China
| | - Shaoming Fang
- Fujian Agriculture and Forestry University, Fuzhou, China
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Zhang J, Yao Y, Li H, Ye S. miR-28-3p inhibits prostate cancer cell proliferation, migration and invasion, and promotes apoptosis by targeting ARF6. Exp Ther Med 2021; 22:1205. [PMID: 34584550 PMCID: PMC8422405 DOI: 10.3892/etm.2021.10639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 06/28/2021] [Indexed: 12/24/2022] Open
Abstract
Previous studies have reported that the expression levels of microRNA (miR)-28-3p are downregulated in prostate cancer (PCa) compared with those in adjacent normal tissues. However, to the best of our knowledge, the function and underlying mechanisms of miR-28-3p in PCa have not been reported. The present study aimed to explore the role of miR-28-3p and its mechanism in the development of PCa. In the present study, miR-28-3p and ADP-ribosylation factor 6 (ARF6) expression levels were analyzed using reverse transcription-quantitative PCR (RT-qPCR). Cell proliferation, colony formation, apoptosis, migration and invasion were determined using Cell Counting Kit-8, colony forming, flow cytometry and Transwell assays, respectively. The association between miR-28-3p and ARF6 was investigated using a dual luciferase reporter assay. ARF6, Rac1, Erk1/2 and phosphorylated (p)-Erk1/2 protein expression levels were analyzed using western blotting. The results of the present study revealed that miR-28-3p expression levels were downregulated, whereas ARF6 expression levels were upregulated in PCa cell lines (LNCaP, 22Rv-1, PC-3 and DU145) compared with those in the normal prostate line RWPE-1. The overexpression of miR-28-3p promoted cell apoptosis, and inhibited cell proliferation, colony formation, migration and invasion. However, the knockdown of miR-28-3p exerted the opposite results. The results of the dual luciferase reporter assays, RT-qPCR and western blotting indicated that ARF6 was a target gene of miR-28-3p. Finally, rescue experiments demonstrated that ARF6 overexpression attenuated the effects of the miR-28-3p mimic by upregulating Rac1 and p-Erk1/2 expression in PCa cells. In conclusion, these findings indicated that miR-28-3p may inhibit the biological behaviors of PCa cells by targeting ARF6, and therefore may represent a novel therapeutic candidate for PCa.
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Affiliation(s)
- Jiabin Zhang
- Department of Urology, Mindong Hospital Affiliated to Fujian Medical University, Ningde, Fujian 355000, P.R. China
| | - Yi Yao
- Department of Urology, Mindong Hospital Affiliated to Fujian Medical University, Ningde, Fujian 355000, P.R. China
| | - Huizhang Li
- Department of Urology, Mindong Hospital Affiliated to Fujian Medical University, Ningde, Fujian 355000, P.R. China
| | - Shihua Ye
- Department of Urology, Mindong Hospital Affiliated to Fujian Medical University, Ningde, Fujian 355000, P.R. China
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Lüttgenau SM, Emming C, Wagner T, Harms J, Guske J, Weber K, Neugebauer U, Schröter R, Panichkina O, Pethő Z, Weber F, Schwab A, Wege AK, Nedvetsky P, Krahn MP. Pals1 prevents Rac1-dependent colorectal cancer cell metastasis by inhibiting Arf6. Mol Cancer 2021; 20:74. [PMID: 33941200 PMCID: PMC8094600 DOI: 10.1186/s12943-021-01354-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 03/24/2021] [Indexed: 11/21/2022] Open
Abstract
Loss of apical-basal polarity and downregulation of cell-cell contacts is a critical step during the pathogenesis of cancer. Both processes are regulated by the scaffolding protein Pals1, however, it is unclear whether the expression of Pals1 is affected in cancer cells and whether Pals1 is implicated in the pathogenesis of the disease. Using mRNA expression data and immunostainings of cancer specimen, we show that Pals1 is frequently downregulated in colorectal cancer, correlating with poorer survival of patients. We further found that Pals1 prevents cancer cell metastasis by controlling Rac1-dependent cell migration through inhibition of Arf6, which is independent of the canonical binding partners of Pals1. Loss of Pals1 in colorectal cancer cells results in increased Arf6 and Rac1 activity, enhanced cell migration and invasion in vitro and increased metastasis of transplanted tumor cells in mice. Thus, our data reveal a new function of Pals1 as a key inhibitor of cell migration and metastasis of colorectal cancer cells. Notably, this new function is independent of the known role of Pals1 in tight junction formation and apical-basal polarity.
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Affiliation(s)
- Simona Mareike Lüttgenau
- Department of Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer-Campus 1-A14, 48149, Münster, Germany
| | - Christin Emming
- Department of Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer-Campus 1-A14, 48149, Münster, Germany
| | - Thomas Wagner
- Department of Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer-Campus 1-A14, 48149, Münster, Germany
| | - Julia Harms
- Department of Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer-Campus 1-A14, 48149, Münster, Germany
| | - Justine Guske
- Department of Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer-Campus 1-A14, 48149, Münster, Germany
| | - Katrin Weber
- Department of Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer-Campus 1-A14, 48149, Münster, Germany
| | - Ute Neugebauer
- Department of Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer-Campus 1-A14, 48149, Münster, Germany
| | - Rita Schröter
- Department of Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer-Campus 1-A14, 48149, Münster, Germany
| | - Olga Panichkina
- Department of Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer-Campus 1-A14, 48149, Münster, Germany
| | - Zoltán Pethő
- Institute of Physiology, University of Münster, Münster, Germany
| | - Florian Weber
- Institute for Pathology, University of Regensburg, Regensburg, Germany
| | - Albrecht Schwab
- Institute of Physiology, University of Münster, Münster, Germany
| | - Anja Kathrin Wege
- Department of Gynaecology and Obstetrics, University Medical Centre Regensburg, Regensburg, Germany
| | - Pavel Nedvetsky
- Department of Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer-Campus 1-A14, 48149, Münster, Germany
| | - Michael P Krahn
- Department of Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer-Campus 1-A14, 48149, Münster, Germany.
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Wang S, Wang T, Gu P. microRNA-145-5p Inhibits Migration, Invasion, and Metastasis in Hepatocellular Carcinoma by Inhibiting ARF6. Cancer Manag Res 2021; 13:3473-3484. [PMID: 33907470 PMCID: PMC8071082 DOI: 10.2147/cmar.s300678] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 04/02/2021] [Indexed: 12/17/2022] Open
Abstract
Purpose Hepatocellular carcinoma (HCC) has the fourth highest rate of mortality among the different types of cancer worldwide. This study aimed to investigate the functions of microRNA-145-5p and AFR6 on migration, invasion and metastasis in HCC. Methods A total of 150 pairs of tumor and their matched adjacent nontumor liver tissues were collected from HCC patients. Expressions of microRNA-145-5p and AFR6 were measured by real-time PCR in HCC tissues and in HCC cell lines. The correlations between microRNA-145-5p and HCC prognosis were investigated. The proliferation, migration, invasion, cell cycle progression, and apoptosis of HCCLM3 cells were evaluated with CCK8, wound healing, transwell, and flow cytometric experiments. Results The expression of miR-145-5p was confirmed to be downregulated not only in HCC tissues but also in several HCC cell lines compared with normal controls. A low expression level of miR-145-5p was notably associated with poor prognosis in patients with HCC and certain characteristics of metastatic tumors. In vitro, miR-145-5p negatively regulated cell proliferation, migration, and invasion and induced apoptosis in HCCLM3 cells. Subsequent experiments further verified that ARF6 is a novel target of miR-145-5p and is significantly overexpressed in HCC tissues. Overexpression of ARF6 circumvented the effects of miR-145-5p in HCCLM3 cells. Conclusion miR-145-5p may play a pivotal role in HCC metastasis via regulating ARF6, and these findings may both provide further insights into the key factors of HCC metastasis and prove to be useful in the development of novel treatment options for HCC.
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Affiliation(s)
- Shuo Wang
- Department of Orthopedics Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310006, People's Republic of China
| | - Tianjiao Wang
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, 310051, People's Republic of China
| | - Pengcheng Gu
- Department of Orthopedics Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310006, People's Republic of China
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Lei H, Ma F, Jia R, Tan B. Effects of Arf6 downregulation on biological characteristics of human prostate cancer cells. Int Braz J Urol 2020; 46:950-961. [PMID: 32822124 PMCID: PMC7527080 DOI: 10.1590/s1677-5538.ibju.2019.0499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/24/2019] [Indexed: 11/21/2022] Open
Abstract
Objective To evaluate the effects of Arf6 downregulation on human prostate cancer cells. Materials and Methods The effects of Arf6 downregulation on cell proliferation, migration, invasion and apoptosis were assessed by MTT, BrdU, scratch, Transwell assays and flow cytometry respectively. AKT, p-AKT, ERK1/2, p-ERK1/2 and Rac1 protein expressions were detected by Western blot. Results Downregulating Arf6 by siRNA interference suppressed the mRNA and protein expressions of Arf6. The proliferation capacities of siRNA group at 48h, 72h, and 96h were significantly lower than those of control group (P <0.05). The migration distance of siRNA group at 18h was significantly shorter than that of control group (P <0.01). The number of cells penetrating Transwell chamber membrane significantly decreased in siRNA group compared with that of control group (P <0.01). After 24h, negative control and normal control groups had similar apoptotic rates (P >0.05) which were both significantly lower than that of siRNA group (P <0.01). After Arf6 expression was downregulated, p-ERK1/2 and Rac1 protein expressions were significantly lower than those of control group (P <0.05). Conclusion Downregulating Arf6 expression can inhibit the proliferation, migration and invasion of prostate cancer cells in vitro, which may be related to ERK1/2 phosphorylation and Rac1 downregulation.
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Affiliation(s)
- Haiming Lei
- School of Clinical Medicine, Jiangsu Vocational College of Medicine, Yancheng, Jiangsu Province, China
| | - Fujun Ma
- Department of Urology, Shengli Oilfield Central Hospital, Dongying, Shandong Province, China
| | - Renfeng Jia
- Department of Urology, Shengli Oilfield Central Hospital, Dongying, Shandong Province, China
| | - Bo Tan
- Department of Urology, Shengli Oilfield Central Hospital, Dongying, Shandong Province, China
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Abdul-Salam VB, Russomanno G, Chien-Nien C, Mahomed AS, Yates LA, Wilkins MR, Zhao L, Gierula M, Dubois O, Schaeper U, Endruschat J, Wojciak-Stothard B. CLIC4/Arf6 Pathway. Circ Res 2019; 124:52-65. [PMID: 30582444 PMCID: PMC6325770 DOI: 10.1161/circresaha.118.313705] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
RATIONALE Increased expression of CLIC4 (chloride intracellular channel 4) is a feature of endothelial dysfunction in pulmonary arterial hypertension, but its role in disease pathology is not fully understood. OBJECTIVE To identify CLIC4 effectors and evaluate strategies targeting CLIC4 signaling in pulmonary hypertension. METHODS AND RESULTS Proteomic analysis of CLIC4-interacting proteins in human pulmonary artery endothelial cells identified regulators of endosomal trafficking, including Arf6 (ADP ribosylation factor 6) GTPase activating proteins and clathrin, while CLIC4 overexpression affected protein regulators of vesicular trafficking, lysosomal function, and inflammation. CLIC4 reduced BMPRII (bone morphogenetic protein receptor II) expression and signaling as a result of Arf6-mediated reduction in gyrating clathrin and increased lysosomal targeting of the receptor. BMPRII expression was restored by Arf6 siRNA, Arf inhibitor Sec7 inhibitor H3 (SecinH3), and inhibitors of clathrin-mediated endocytosis but was unaffected by chloride channel inhibitor, indanyloxyacetic acid 94 or Arf1 siRNA. The effects of CLIC4 on NF-κB (nuclear factor-kappa B), HIF (hypoxia-inducible factor), and angiogenic response were prevented by Arf6 siRNA and SecinH3. Sugen/hypoxia mice and monocrotaline rats showed elevated expression of CLIC4, activation of Arf6 and NF-κB, and reduced expression of BMPRII in the lung. These changes were established early during disease development. Lung endothelium-targeted delivery of CLIC4 siRNA or treatment with SecinH3 attenuated the disease, reduced CLIC4/Arf activation, and restored BMPRII expression in the lung. Endothelial colony-forming cells from idiopathic pulmonary hypertensive patients showed upregulation of CLIC4 expression and Arf6 activity, suggesting potential importance of this pathway in the human condition. CONCLUSIONS Arf6 is a novel effector of CLIC4 and a new therapeutic target in pulmonary hypertension.
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Affiliation(s)
- Vahitha B Abdul-Salam
- From the Centre for Pharmacology and Therapeutics (V.B.A.-S., G.R., C.C.-N., A.S.M., M.R.W., L.Z., M.G., O.D., B.W.-S.), Department of Medicine, Imperial College London, United Kingdom
| | - Giusy Russomanno
- From the Centre for Pharmacology and Therapeutics (V.B.A.-S., G.R., C.C.-N., A.S.M., M.R.W., L.Z., M.G., O.D., B.W.-S.), Department of Medicine, Imperial College London, United Kingdom
| | - Chen Chien-Nien
- From the Centre for Pharmacology and Therapeutics (V.B.A.-S., G.R., C.C.-N., A.S.M., M.R.W., L.Z., M.G., O.D., B.W.-S.), Department of Medicine, Imperial College London, United Kingdom
| | - Abdul S Mahomed
- From the Centre for Pharmacology and Therapeutics (V.B.A.-S., G.R., C.C.-N., A.S.M., M.R.W., L.Z., M.G., O.D., B.W.-S.), Department of Medicine, Imperial College London, United Kingdom
| | - Luke A Yates
- Section of Structural Biology (L.A.Y.), Department of Medicine, Imperial College London, United Kingdom
| | - Martin R Wilkins
- From the Centre for Pharmacology and Therapeutics (V.B.A.-S., G.R., C.C.-N., A.S.M., M.R.W., L.Z., M.G., O.D., B.W.-S.), Department of Medicine, Imperial College London, United Kingdom
| | - Lan Zhao
- From the Centre for Pharmacology and Therapeutics (V.B.A.-S., G.R., C.C.-N., A.S.M., M.R.W., L.Z., M.G., O.D., B.W.-S.), Department of Medicine, Imperial College London, United Kingdom
| | - Magdalena Gierula
- From the Centre for Pharmacology and Therapeutics (V.B.A.-S., G.R., C.C.-N., A.S.M., M.R.W., L.Z., M.G., O.D., B.W.-S.), Department of Medicine, Imperial College London, United Kingdom
| | - Oliver Dubois
- From the Centre for Pharmacology and Therapeutics (V.B.A.-S., G.R., C.C.-N., A.S.M., M.R.W., L.Z., M.G., O.D., B.W.-S.), Department of Medicine, Imperial College London, United Kingdom
| | - Ute Schaeper
- Silence Therapeutics GmbH, Berlin, Germany (U.S., J.E.)
| | | | - Beata Wojciak-Stothard
- From the Centre for Pharmacology and Therapeutics (V.B.A.-S., G.R., C.C.-N., A.S.M., M.R.W., L.Z., M.G., O.D., B.W.-S.), Department of Medicine, Imperial College London, United Kingdom
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Zaoui K, Rajadurai CV, Duhamel S, Park M. Arf6 regulates RhoB subcellular localization to control cancer cell invasion. J Cell Biol 2019; 218:3812-3826. [PMID: 31591185 PMCID: PMC6829653 DOI: 10.1083/jcb.201806111] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 12/21/2018] [Accepted: 08/12/2019] [Indexed: 12/14/2022] Open
Abstract
The ADP-ribosylation factor 6 (Arf6) is a small GTPase that regulates endocytic recycling processes in concert with various effectors. Arf6 controls cytoskeletal organization and membrane trafficking; however, the detailed mechanisms of regulation remain poorly understood. Here, we report that Arf6 forms a complex with RhoB. The interaction between RhoB and Arf6 is mediated by the GCI (glycine, cysteine, and isoleucine) residues (188-190) of RhoB. Specific targeting of Arf6 to plasma membrane or mitochondrial membranes promotes recruitment and colocalization of RhoB to these membrane microdomains. Arf6 depletion promotes the loss of RhoB from endosomal membranes and leads to RhoB degradation through an endolysosomal pathway. This results in defective actin and focal adhesion dynamics and increased 3D cell migration upon activation of the Met receptor tyrosine kinase. Our findings identify a novel regulatory mechanism for RhoB localization and stability by Arf6 and establish the strict requirement of Arf6 for RhoB-specific subcellular targeting to endosomes and biological functions.
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Affiliation(s)
- Kossay Zaoui
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada.,Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, Quebec, Canada
| | - Charles V Rajadurai
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada.,Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, Quebec, Canada
| | - Stéphanie Duhamel
- Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, Quebec, Canada
| | - Morag Park
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada .,Rosalind and Morris Goodman Cancer Centre, McGill University, Montreal, Quebec, Canada.,Department of Medicine, McGill University, Montreal, Quebec, Canada.,Department of Oncology, McGill University, Montreal, Quebec, Canada
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Wang G, Gormley M, Qiao J, Zhao Q, Wang M, Di Sante G, Deng S, Dong L, Pestell T, Ju X, Casimiro MC, Addya S, Ertel A, Tozeren A, Li Q, Yu Z, Pestell RG. Cyclin D1-mediated microRNA expression signature predicts breast cancer outcome. Theranostics 2018; 8:2251-2263. [PMID: 29721077 PMCID: PMC5928887 DOI: 10.7150/thno.23877] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 12/25/2017] [Indexed: 01/03/2023] Open
Abstract
Background: Genetic classification of breast cancer based on the coding mRNA suggests the evolution of distinct subtypes. Whether the non-coding genome is altered concordantly with the coding genome and the mechanism by which the cell cycle directly controls the non-coding genome is poorly understood. Methods: Herein, the miRNA signature maintained by endogenous cyclin D1 in human breast cancer cells was defined. In order to determine the clinical significance of the cyclin D1-mediated miRNA signature, we defined a miRNA expression superset from 459 breast cancer samples. We compared the coding and non-coding genome of breast cancer subtypes. Results: Hierarchical clustering of human breast cancers defined four distinct miRNA clusters (G1-G4) associated with distinguishable relapse-free survival by Kaplan-Meier analysis. The cyclin D1-regulated miRNA signature included several oncomirs, was conserved in multiple breast cancer cell lines, was associated with the G2 tumor miRNA cluster, ERα+ status, better outcome and activation of the Wnt pathway. The coding and non-coding genome were discordant within breast cancer subtypes. Seed elements for cyclin D1-regulated miRNA were identified in 63 genes of the Wnt signaling pathway including DKK. Cyclin D1 restrained DKK1 via the 3'UTR. In vivo studies using inducible transgenics confirmed cyclin D1 induces Wnt-dependent gene expression. Conclusion: The non-coding genome defines breast cancer subtypes that are discordant with their coding genome subtype suggesting distinct evolutionary drivers within the tumors. Cyclin D1 orchestrates expression of a miRNA signature that induces Wnt/β-catenin signaling, therefore cyclin D1 serves both upstream and downstream of Wnt/β-catenin signaling.
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Affiliation(s)
- Guangxue Wang
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Michael Gormley
- Department of Cancer Biology, Thomas Jefferson University, 233 South 10 th St. Philadelphia PA 19107
| | - Jing Qiao
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Qian Zhao
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Min Wang
- Pennsylvania Cancer and Regenerative Medicine Research Center, Baruch S. Blumberg Institute, Pennsylvania Biotechnology Center and Lankenau Institute for Medical Research, 100 East Lancaster Avenue, Suite, 222, Wynnewood, PA. 19096
| | - Gabriele Di Sante
- Pennsylvania Cancer and Regenerative Medicine Research Center, Baruch S. Blumberg Institute, Pennsylvania Biotechnology Center and Lankenau Institute for Medical Research, 100 East Lancaster Avenue, Suite, 222, Wynnewood, PA. 19096
| | - Shengqiong Deng
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Shanghai Gongli Hospital, the Second Military Medical University, Shanghai 200120, China
| | - Lin Dong
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Tim Pestell
- Department of Cancer Biology, Thomas Jefferson University, 233 South 10 th St. Philadelphia PA 19107
| | - Xiaoming Ju
- Department of Cancer Biology, Thomas Jefferson University, 233 South 10 th St. Philadelphia PA 19107
| | - Mathew C. Casimiro
- Pennsylvania Cancer and Regenerative Medicine Research Center, Baruch S. Blumberg Institute, Pennsylvania Biotechnology Center and Lankenau Institute for Medical Research, 100 East Lancaster Avenue, Suite, 222, Wynnewood, PA. 19096
| | - Sankar Addya
- Department of Cancer Biology, Thomas Jefferson University, 233 South 10 th St. Philadelphia PA 19107
| | - Adam Ertel
- Department of Cancer Biology, Thomas Jefferson University, 233 South 10 th St. Philadelphia PA 19107
| | - Ayden Tozeren
- Center for Integrated Bioinformatics, Drexel University, Philadelphia, PA 19104
- School of Biomedical Engineering, Systems and Health Sciences, Drexel University, Philadelphia, PA 19104
| | - Qinchuan Li
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Zuoren Yu
- Pennsylvania Cancer and Regenerative Medicine Research Center, Baruch S. Blumberg Institute, Pennsylvania Biotechnology Center and Lankenau Institute for Medical Research, 100 East Lancaster Avenue, Suite, 222, Wynnewood, PA. 19096
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Richard G. Pestell
- Pennsylvania Cancer and Regenerative Medicine Research Center, Baruch S. Blumberg Institute, Pennsylvania Biotechnology Center and Lankenau Institute for Medical Research, 100 East Lancaster Avenue, Suite, 222, Wynnewood, PA. 19096
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 637551, Singapore
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Qiu J, Tao L, Wei Q, Zhang P. Knockdown of Arf6 increases drug sensitivity and inhibits proliferation, migration and invasion in gastric cancer SGC-7901 cells. Oncol Lett 2017; 15:2147-2152. [PMID: 29434918 PMCID: PMC5777091 DOI: 10.3892/ol.2017.7558] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 11/02/2017] [Indexed: 12/13/2022] Open
Abstract
ADP-ribosylation factor 6 (Arf6), a member of the ADP-ribosylation factor family, is overexpressed in different types of cancer cell and promotes invasion, metastasis and drug resistance. However, the potential functions of Arf6 in gastric cancer (GC), and the molecular mechanism underlying these functions, remain to be fully elucidated. In the present study, the results demonstrated that in vitro knockdown of Arf6 decreased proliferation, colony formation, migration and invasion in SGC-7901 cells. Arf6 knockdown also markedly decreased the activity of the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway. Furthermore, knockdown of Arf6 was associated with elevated chemosensitivity of SGC-7901 cells to 5-fluorouracil through inactivation of the ERK1/2 signaling pathway. Taken together, these results suggest that Arf6 is involved in regulating proliferation, migration, invasion and drug resistance in GC, and may be a potential therapeutic target for the treatment of GC.
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Affiliation(s)
- Junlan Qiu
- Department of General Surgery, Nanjing Drum Tower Hospital Clinical College, Nanjing Medical University, Nanjing, Jiangsu 210008, P.R. China
| | - Liang Tao
- Department of General Surgery, Nanjing Drum Tower Hospital Clinical College, Nanjing Medical University, Nanjing, Jiangsu 210008, P.R. China
| | - Qiang Wei
- Nanjing Emergency Medical Center, Nanjing, Jiangsu 210003, P.R. China
| | - Pingyang Zhang
- Department of Cardiovascular Ultrasound, Nanjing First Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu 210006, P.R. China
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11
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Association between epidermal growth factor receptor amplification and ADP-ribosylation factor 1 methylation in human glioblastoma. Cell Oncol (Dordr) 2017. [PMID: 28631186 DOI: 10.1007/s13402-017-0329-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
PURPOSE Glioblastoma (GB) is the most frequent and most malignant primary brain tumor in adults. Previously, it has been found that both genetic and epigenetic factors may play critical roles in its etiology and prognosis. In addition, it has been found that the epidermal growth factor receptor gene (EGFR) is frequently over-expressed and amplified in primary GBs. Here, we assessed the promoter methylation status of 10 genes relevant to GB and explored associations between these findings and the EGFR gene amplification status. METHODS Tumor samples were obtained from 36 patients with primary GBs. In addition, 6 control specimens were included from patients who were operated for diseases other than brain tumors. The amplification status of the EGFR gene, and its deletion mutant EGFRvIII, were evaluated using FISH and MLPA, respectively. The IDH1/2 gene mutation status was verified using Sanger sequencing. A commercial DNA methylation kit was used to assess the promoter methylation status of 10 pre-selected genes. Metabolic profiles were measured using HR-MAS NMR spectroscopy. The EGFR and ARF1 mRNA expression levels were quantified using qRT-PCR. RESULTS Of the 10 genes analyzed, we found that only ARF1 promoter hypermethylation was significantly associated with EGFR gene amplification. ARF1 is a GTPase that is involved in vesicle trafficking and the Golgi apparatus. Subsequent tumor metabolism measurements revealed a positive association between EGFR amplification and different membrane precursors and methyl-donor metabolites. Finally, we found that EGFR gene amplifications were associated with distinct tumor infiltration patterns, thus representing a putative novel functional association between EGFR gene amplification and ARF1 gene promoter methylation in GB. CONCLUSIONS The results reported here provide a basis for a new hypotheses connecting EGFR gene amplification in GB cells with ARF1 gene promoter methylation, vesicle trafficking, membrane turnover and tumor metabolism. The mechanism(s) underlying these connections and their functional consequences remain to be established.
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Li R, Peng C, Zhang X, Wu Y, Pan S, Xiao Y. Roles of Arf6 in cancer cell invasion, metastasis and proliferation. Life Sci 2017. [PMID: 28625359 DOI: 10.1016/j.lfs.2017.06.008] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
ADP-ribosylation factor 6 (Arf6), a member of small GTPases ADP-ribosylation factor (Arf) family, expresses widely in mammalian cells and mainly regulates the functions of membrane traffic and actin remodeling. Current studies indicated that the activation and high expression of Arf6 protein may be significantly correlated with the invasion and metastasis of several tumors, such as breast cancer, pancreatic cancer, lung cancer, etc. Meanwhile, the ability of tumor invasion and metastasis can be suppressed when Arf6 activity is blocked by the inhibitors or small-interfering RNAs of Arf6. To explore the precisely potential mechanisms between Arf6 and the process of tumor invasion, metastasis and proliferation, we concludes the functions and potential signaling pathways of Arf6 in tumor cells and provides an overview about clinical prospects of Arf6 in the screening, diagnosis, treatment and evaluation of prognosis of neoplasms.
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Affiliation(s)
- Rui Li
- Department of Biochemistry and Molecular Biology, College of Basic Medical Science, Jilin University, Changchun, China; Department of Radiology, School of Public Health, Jilin University, Changchun, China
| | - Cheng Peng
- Department of Hand and Foot Surgery, The First Hospital of Jilin University, Changchun, China
| | - Xianzhe Zhang
- School of Clinical Medicine, Jilin University, Changchun, China
| | - Yuewei Wu
- School of Clinical Medicine, Jilin University, Changchun, China
| | - Shida Pan
- School of Clinical Medicine, Jilin University, Changchun, China
| | - Yechen Xiao
- Department of Biochemistry and Molecular Biology, College of Basic Medical Science, Jilin University, Changchun, China.
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13
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The small G protein Arf6 expressed in keratinocytes by HGF stimulation is a regulator for skin wound healing. Sci Rep 2017; 7:46649. [PMID: 28429746 PMCID: PMC5399375 DOI: 10.1038/srep46649] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 03/24/2017] [Indexed: 12/21/2022] Open
Abstract
The earlier step of cutaneous wound healing process, re-epithelialization of the wounded skin, is triggered by a variety of growth factors. However, molecular mechanisms through which growth factors trigger skin wound healing are less understood. Here, we demonstrate that hepatocyte growth factor (HGF)/c-Met signaling-induced expression of the small G protein Arf6 mRNA in keratinocytes is essential for the skin wound healing. Arf6 mRNA expression was dramatically induced in keratinocytes at the wounded skin, which was specifically suppressed by the c-Met inhibitor. Wound healing of the skin was significantly delayed in keratinocyte-specific Arf6 conditional knockout mice. Furthermore, Arf6 deletion from keratinocytes remarkably suppressed HGF-stimulated cell migration and peripheral membrane ruffle formation, but did not affect skin morphology and proliferation/differentiation of keratinocytes. These results are consistent with the notion that Arf6 expressed in skin keratinocytes through the HGF/c-Met signaling pathway in response to skin wounding plays an important role in skin wound healing by regulating membrane dynamics-based motogenic cellular function of keratinocytes.
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14
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Grossmann AH, Zhao H, Jenkins N, Zhu W, Richards JR, Yoo JH, Winter JM, Rich B, Mleynek TM, Li DY, Odelberg SJ. The small GTPase ARF6 regulates protein trafficking to control cellular function during development and in disease. Small GTPases 2016; 10:1-12. [PMID: 28001501 DOI: 10.1080/21541248.2016.1259710] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The activation of the small GTPase ARF6 has been implicated in promoting several pathological processes related to vascular instability and tumor formation, growth, and metastasis. ARF6 also plays a vital role during embryonic development. Recent studies have suggested that ARF6 carries out these disparate functions primarily by controlling protein trafficking within the cell. ARF6 helps direct proteins to intracellular or extracellular locations where they function in normal cellular responses during development and in pathological processes later in life. This transport of proteins is accomplished through a variety of mechanisms, including endocytosis and recycling, microvesicle release, and as yet uncharacterized processes. This Commentary will explore the functions of ARF6, while focusing on the role of this small GTPase in development and postnatal physiology, regulating barrier function and diseases associated with its loss, and tumor formation, growth, and metastasis.
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Affiliation(s)
- Allie H Grossmann
- a Department of Medicine , Program in Molecular Medicine, University of Utah , Salt Lake City , UT , USA.,b Department of Pathology , University of Utah , Salt Lake City , UT , USA.,c ARUP Laboratories, University of Utah , Salt Lake City , UT , USA
| | - Helong Zhao
- a Department of Medicine , Program in Molecular Medicine, University of Utah , Salt Lake City , UT , USA
| | - Noah Jenkins
- a Department of Medicine , Program in Molecular Medicine, University of Utah , Salt Lake City , UT , USA
| | - Weiquan Zhu
- a Department of Medicine , Program in Molecular Medicine, University of Utah , Salt Lake City , UT , USA.,d Department of Medicine , Division of Cardiovascular Medicine, University of Utah , Salt Lake City , UT , USA
| | - Jackson R Richards
- a Department of Medicine , Program in Molecular Medicine, University of Utah , Salt Lake City , UT , USA.,e Department of Oncological Sciences , University of Utah , Salt Lake City , UT , USA
| | - Jae Hyuk Yoo
- a Department of Medicine , Program in Molecular Medicine, University of Utah , Salt Lake City , UT , USA.,e Department of Oncological Sciences , University of Utah , Salt Lake City , UT , USA
| | - Jacob M Winter
- a Department of Medicine , Program in Molecular Medicine, University of Utah , Salt Lake City , UT , USA
| | - Bianca Rich
- a Department of Medicine , Program in Molecular Medicine, University of Utah , Salt Lake City , UT , USA
| | - Tara M Mleynek
- a Department of Medicine , Program in Molecular Medicine, University of Utah , Salt Lake City , UT , USA
| | - Dean Y Li
- a Department of Medicine , Program in Molecular Medicine, University of Utah , Salt Lake City , UT , USA.,d Department of Medicine , Division of Cardiovascular Medicine, University of Utah , Salt Lake City , UT , USA.,e Department of Oncological Sciences , University of Utah , Salt Lake City , UT , USA.,f Department of Human Genetics , University of Utah , Salt Lake City , UT , USA.,g Sichuan Provincial Key Laboratory for Human Disease Gene Study , Sichuan Provincial People's Hospital, Chinese Academy of Sciences , Chengdu , China.,h Department of Cardiology , VA Salt Lake City Health Care System , Salt Lake City , UT , USA.,i Navigen Inc. , Salt Lake City , UT , USA
| | - Shannon J Odelberg
- a Department of Medicine , Program in Molecular Medicine, University of Utah , Salt Lake City , UT , USA.,d Department of Medicine , Division of Cardiovascular Medicine, University of Utah , Salt Lake City , UT , USA.,j Department of Neurobiology and Anatomy , University of Utah , Salt Lake City , UT , USA
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15
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Yoo JH, Shi DS, Grossmann AH, Sorensen LK, Tong Z, Mleynek TM, Rogers A, Zhu W, Richards JR, Winter JM, Zhu J, Dunn C, Bajji A, Shenderovich M, Mueller AL, Woodman SE, Harbour JW, Thomas KR, Odelberg SJ, Ostanin K, Li DY. ARF6 Is an Actionable Node that Orchestrates Oncogenic GNAQ Signaling in Uveal Melanoma. Cancer Cell 2016; 29:889-904. [PMID: 27265506 PMCID: PMC5027844 DOI: 10.1016/j.ccell.2016.04.015] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Revised: 10/16/2015] [Accepted: 04/29/2016] [Indexed: 12/12/2022]
Abstract
Activating mutations in Gαq proteins, which form the α subunit of certain heterotrimeric G proteins, drive uveal melanoma oncogenesis by triggering multiple downstream signaling pathways, including PLC/PKC, Rho/Rac, and YAP. Here we show that the small GTPase ARF6 acts as a proximal node of oncogenic Gαq signaling to induce all of these downstream pathways as well as β-catenin signaling. ARF6 activates these diverse pathways through a common mechanism: the trafficking of GNAQ and β-catenin from the plasma membrane to cytoplasmic vesicles and the nucleus, respectively. Blocking ARF6 with a small-molecule inhibitor reduces uveal melanoma cell proliferation and tumorigenesis in a mouse model, confirming the functional relevance of this pathway and suggesting a therapeutic strategy for Gα-mediated diseases.
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Affiliation(s)
- Jae Hyuk Yoo
- Department of Medicine, Program in Molecular Medicine, University of Utah, 15 North 2030 East, Salt Lake City, UT 84112, USA; Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Dallas S Shi
- Department of Medicine, Program in Molecular Medicine, University of Utah, 15 North 2030 East, Salt Lake City, UT 84112, USA; Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Allie H Grossmann
- Department of Medicine, Program in Molecular Medicine, University of Utah, 15 North 2030 East, Salt Lake City, UT 84112, USA; Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA; ARUP Laboratories, University of Utah, Salt Lake City, UT 84112, USA
| | - Lise K Sorensen
- Department of Medicine, Program in Molecular Medicine, University of Utah, 15 North 2030 East, Salt Lake City, UT 84112, USA
| | - ZongZhong Tong
- Navigen Inc., 383 Colorow Drive, Salt Lake City, UT 84108, USA; Key Laboratory for Human Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu 610072, China
| | - Tara M Mleynek
- Department of Medicine, Program in Molecular Medicine, University of Utah, 15 North 2030 East, Salt Lake City, UT 84112, USA
| | - Aaron Rogers
- Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
| | - Weiquan Zhu
- Department of Medicine, Program in Molecular Medicine, University of Utah, 15 North 2030 East, Salt Lake City, UT 84112, USA; Division of Cardiovascular Medicine, Department of Medicine, University of Utah, Salt Lake City, UT 84112, USA
| | - Jackson R Richards
- Department of Medicine, Program in Molecular Medicine, University of Utah, 15 North 2030 East, Salt Lake City, UT 84112, USA; Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Jacob M Winter
- Department of Medicine, Program in Molecular Medicine, University of Utah, 15 North 2030 East, Salt Lake City, UT 84112, USA
| | - Jie Zhu
- Department of Ophthalmology and Shiley Eye Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Christine Dunn
- Navigen Inc., 383 Colorow Drive, Salt Lake City, UT 84108, USA
| | - Ashok Bajji
- Navigen Inc., 383 Colorow Drive, Salt Lake City, UT 84108, USA; VioGen Biosciences LLC, Salt Lake City, UT 84119, USA
| | - Mark Shenderovich
- Navigen Inc., 383 Colorow Drive, Salt Lake City, UT 84108, USA; Mol3D Research LLC, Salt Lake City, UT 84124, USA
| | - Alan L Mueller
- Navigen Inc., 383 Colorow Drive, Salt Lake City, UT 84108, USA
| | - Scott E Woodman
- Department of Melanoma Medical Oncology, Department of Systems Biology, University of Texas, MD Anderson Cancer Center, Houston, TX 77054, USA
| | - J William Harbour
- Ocular Oncology Service, Bascom Palmer Eye Institute and Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Kirk R Thomas
- Department of Medicine, Program in Molecular Medicine, University of Utah, 15 North 2030 East, Salt Lake City, UT 84112, USA; Division of Hematology, Department of Medicine, University of Utah, Salt Lake City, UT 84112, USA
| | - Shannon J Odelberg
- Department of Medicine, Program in Molecular Medicine, University of Utah, 15 North 2030 East, Salt Lake City, UT 84112, USA; Division of Cardiovascular Medicine, Department of Medicine, University of Utah, Salt Lake City, UT 84112, USA; Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84112, USA
| | - Kirill Ostanin
- Navigen Inc., 383 Colorow Drive, Salt Lake City, UT 84108, USA.
| | - Dean Y Li
- Department of Medicine, Program in Molecular Medicine, University of Utah, 15 North 2030 East, Salt Lake City, UT 84112, USA; Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84112, USA; Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA; ARUP Laboratories, University of Utah, Salt Lake City, UT 84112, USA; Key Laboratory for Human Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu 610072, China; Division of Cardiovascular Medicine, Department of Medicine, University of Utah, Salt Lake City, UT 84112, USA; Department of Cardiology, VA Salt Lake City Health Care System, Salt Lake City, UT 84112, USA.
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16
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The GTPase ARF6 Controls ROS Production to Mediate Angiotensin II-Induced Vascular Smooth Muscle Cell Proliferation. PLoS One 2016; 11:e0148097. [PMID: 26824355 PMCID: PMC4732744 DOI: 10.1371/journal.pone.0148097] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 01/13/2016] [Indexed: 02/07/2023] Open
Abstract
High reactive oxygen species (ROS) levels and enhanced vascular smooth muscle cells (VSMC) proliferation are observed in numerous cardiovascular diseases. The mechanisms by which hormones such as angiotensin II (Ang II) acts to promote these cellular responses remain poorly understood. We have previously shown that the ADP-ribosylation factor 6 (ARF6), a molecular switch that coordinates intracellular signaling events can be activated by the Ang II receptor (AT1R). Whether this small GTP-binding protein controls the signaling events leading to ROS production and therefore Ang II-dependent VSMC proliferation, remains however unknown. Here, we demonstrate that in rat aortic VSMC, Ang II stimulation led to the subsequent activation of ARF6 and Rac1, a key regulator of NADPH oxidase activity. Using RNA interference, we showed that ARF6 is essential for ROS generation since in conditions where this GTPase was knocked down, Ang II could no longer promote superoxide anion production. In addition to regulating Rac1 activity, ARF6 also controlled expression of the NADPH oxidase 1 (Nox 1) as well as the ability of the EGFR to become transactivated. Finally, ARF6 also controlled MAPK (Erk1/2, p38 and Jnk) activation, a key pathway of VSMC proliferation. Altogether, our findings demonstrate that Ang II promotes activation of ARF6 to controls ROS production by regulating Rac1 activation and Nox1 expression. In turn, increased ROS acts to activate the MAPK pathway. These signaling events represent a new molecular mechanism by which Ang II can promote proliferation of VSMC.
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17
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Morgan C, Lewis PD, Hopkins L, Burnell S, Kynaston H, Doak SH. Increased expression of ARF GTPases in prostate cancer tissue. SPRINGERPLUS 2015; 4:342. [PMID: 26185744 PMCID: PMC4499334 DOI: 10.1186/s40064-015-1136-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 07/03/2015] [Indexed: 11/10/2022]
Abstract
PURPOSE ARFs are a family of Ras-related GTP binding proteins, ARF6, in particular, is implicated in cancer invasion and metastasis. However, the role of ARF proteins in prostate cancer have yet to be investigated. METHODS Immunohistochemical staining for ARF6 was performed on a prostate cancer tissue microarray with patient matched normal specimens. RESULTS Antibody staining was significantly over-expressed in prostate cancer patient samples compared to normal patient tissue and a trend towards increased staining intensity in cancer samples with Gleason scores of 8 and above (metastatic disease). CONCLUSION Due to high homology between members of the ARF family we could not determine if ARF 6 was the only ARF over-expressed in the prostate cancer samples. However, we are the first to show that ARF-GTPases are over expressed in prostate cancer which provides further insight into the molecular biology of prostate cancer.
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Affiliation(s)
- Claire Morgan
- Institute of Life Science, Swansea University, Swansea, UK
| | - Paul D Lewis
- Respiratory Diagnostics group, Institute of Life Science 2, Swansea University, Swansea, UK
| | - Lynda Hopkins
- Pathology Department, Singleton Hospital, Swansea, UK
| | | | - Howard Kynaston
- Department of Surgery, Cardiff School of Medicine, Heath Park, Cardiff, UK
| | - Shareen H Doak
- Institute of Life Science, Swansea University, Swansea, UK
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18
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Papini D, Langemeyer L, Abad MA, Kerr A, Samejima I, Eyers PA, Jeyaprakash AA, Higgins JMG, Barr FA, Earnshaw WC. TD-60 links RalA GTPase function to the CPC in mitosis. Nat Commun 2015; 6:7678. [PMID: 26158537 PMCID: PMC4510650 DOI: 10.1038/ncomms8678] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 05/29/2015] [Indexed: 12/26/2022] Open
Abstract
TD-60 (also known as RCC2) is a highly conserved protein that structurally resembles the Ran guanine exchange factor (GEF) RCC1, but has not previously been shown to have GEF activity. TD-60 has a typical chromosomal passenger complex (CPC) distribution in mitotic cells, but associates with integrin complexes and is involved in cell motility during interphase. Here we show that TD-60 exhibits GEF activity, in vitro and in cells, for the small GTPase RalA. TD-60 or RalA depletion causes spindle abnormalities in prometaphase associated with abnormal centromeric accumulation of CPC components. TD-60 and RalA apparently work together to contribute to the regulation of kinetochore-microtubule interactions in early mitosis. Importantly, several mitotic phenotypes caused by TD-60 depletion are reverted by the expression of a GTP-locked mutant, RalA (Q72L). The demonstration that a small GTPase participates in the regulation of the CPC reveals a level of mitotic regulation not suspected in previous studies.
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Affiliation(s)
- Diana Papini
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
- Institute for Cell and Molecular Biosciences (ICaMB), Newcastle University, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Lars Langemeyer
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Maria A. Abad
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Alastair Kerr
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Itaru Samejima
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Patrick A. Eyers
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Crown St, Liverpool L69 7ZB, UK
| | - A. Arockia Jeyaprakash
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Jonathan M. G. Higgins
- Institute for Cell and Molecular Biosciences (ICaMB), Newcastle University, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Francis A. Barr
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - William C. Earnshaw
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
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19
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Yu Z, Wang L, Wang C, Ju X, Wang M, Chen K, Loro E, Li Z, Zhang Y, Wu K, Casimiro MC, Gormley M, Ertel A, Fortina P, Chen Y, Tozeren A, Liu Z, Pestell RG. Cyclin D1 induction of Dicer governs microRNA processing and expression in breast cancer. Nat Commun 2014; 4:2812. [PMID: 24287487 PMCID: PMC3874416 DOI: 10.1038/ncomms3812] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 10/23/2013] [Indexed: 02/07/2023] Open
Abstract
Cyclin D1 encodes the regulatory subunit of a holoenzyme that phosphorylates the pRB protein and promotes G1/S cell cycle progression and oncogenesis. Dicer is a central regulator of miRNA maturation, encoding an enzyme that cleaves double strand RNA or stem-loop-stem RNA into 20–25 nucleotide long small RNA, governing sequence specific gene silencing and heterochromatin methylation. The mechanism by which the cell cycle directly controls the non-coding genome is poorly understood. Here we show that cyclin D1−/− cells are defective in pre-miRNA processing which is restored by cyclin D1a rescue. Cyclin D1 induces Dicer expression in vitro and in vivo. Dicer is transcriptionally targeted by cyclin D1, via a cdk-independent mechanism. Cyclin D1 and Dicer expression significantly correlates in luminal A and basal-like subtypes of human breast cancer. Cyclin D1 and Dicer maintain heterochromatic histone modification (Tri-m-H3K9). Cyclin D1-mediated cellular proliferation and migration is Dicer-dependent. We conclude that cyclin D1 induction of Dicer coordinates microRNA biogenesis.
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Affiliation(s)
- Zuoren Yu
- 1] Department of Cancer Biology, Thomas Jefferson University, 233 South 10th Street, Philadelphia, Pennsylvania 19107, USA [2] Kimmel Cancer Center, Thomas Jefferson University, 233 South 10th Street, Philadelphia, Pennsylvania 19107, USA [3] Research Center for Translational Medicine, Key Laboratory for Basic Research in Cardiology, East Hospital, Tongji University School of Medicine, 150 Jimo Road, Shanghai 200120, China
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Rendleman J, Shang S, Dominianni C, Shields JF, Scanlon P, Adaniel C, Desrichard A, Ma M, Shapiro R, Berman R, Pavlick A, Polsky D, Shao Y, Osman I, Kirchhoff T. Melanoma risk loci as determinants of melanoma recurrence and survival. J Transl Med 2013; 11:279. [PMID: 24188633 PMCID: PMC4228352 DOI: 10.1186/1479-5876-11-279] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 10/16/2013] [Indexed: 12/22/2022] Open
Abstract
Background Steadily high melanoma mortality rates urge for the availability of novel biomarkers with a more personalized ability to predict melanoma clinical outcomes. Germline risk variants are promising candidates for this purpose; however, their prognostic potential in melanoma has never been systematically tested. Methods We examined the effect of 108 melanoma susceptibility single nucleotide polymorphisms (SNPs), associated in recent GWAS with melanoma and melanoma-related phenotypes, on recurrence-free survival (RFS) and overall survival (OS), in 891 prospectively accrued melanoma patients. Cox proportional hazards models (Cox PH) were used to test the associations between 108 melanoma risk SNPs and RFS and OS adjusted by age at diagnosis, gender, tumor stage, histological subtype and other primary tumor characteristics. Results We identified significant associations for rs7538876 (RCC2) with RFS (HR = 1.48, 95% CI = 1.20-1.83, p = 0.0005) and rs9960018 (DLGAP1) with both RFS and OS (HR = 1.43, 95% CI = 1.07-1.91, p = 0.01, HR = 1.52, 95% CI = 1.09-2.12, p = 0.01, respectively) using multivariable Cox PH models. In addition, we developed a logistic regression model that incorporates rs7538876, rs9960018, primary tumor histological type and stage at diagnosis that has an improved discriminatory ability to classify 3-year recurrence (AUC = 82%) compared to histological type and stage alone (AUC = 78%). Conclusions We identified associations between melanoma risk variants and melanoma outcomes. The significant associations observed for rs7538876 and rs9960018 suggest a biological implication of these loci in melanoma progression. The observed predictive patterns of associated variants with clinical end-points suggest for the first time the potential for utilization of genetic risk markers in melanoma prognostication.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Tomas Kirchhoff
- New York University Cancer Institute, New York University School of Medicine, New York, NY 10016, USA.
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21
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Chaineau M, Ioannou MS, McPherson PS. Rab35: GEFs, GAPs and effectors. Traffic 2013; 14:1109-17. [PMID: 23905989 DOI: 10.1111/tra.12096] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 07/30/2013] [Accepted: 08/01/2013] [Indexed: 12/27/2022]
Abstract
Rabs are the largest family of small GTPases and are master regulators of membrane trafficking. Following activation by guanine-nucleotide exchange factors (GEFs), each Rab binds a specific set of effector proteins that mediate the various downstream functions of that Rab. Then, with the help of GTPase-activating proteins, the Rab converts GTP to GDP, terminating its function. There are over 60 Rabs in humans and only a subset has been analyzed in any detail. Recently, Rab35 has emerged as a key regulator of cargo recycling at endosomes, with an additional role in regulation of the actin cytoskeleton. Here, we will focus on the regulation of Rab35 activity by the connecdenn/DENND1 family of GEFs and the TBC1D10/EPI64 family of GTPase-activating proteins. We will describe how analysis of these proteins, as well as a plethora of Rab35 effectors has provided insights into Rab35 function. Finally, we will describe how Rab35 provides a novel link between the Rab and Arf family of GTPases with implications for tumor formation and invasiveness.
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Affiliation(s)
- Mathilde Chaineau
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, H3A 2B4, Canada
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22
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Yang M, Odelberg SJ, Tong Z, Li DY, Looper RE. Cationic dirhodium carboxylate-catalyzed synthesis of dihydropyrimidones from propargyl ureas. Tetrahedron 2013; 69:5744-5750. [PMID: 23807819 PMCID: PMC3690933 DOI: 10.1016/j.tet.2013.04.071] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cationic Rh(II) complexes are able to catalyze the regioselective hydroamination of propargyl ureas in a 6-endo fashion. This transformation permits access to interesting substitution patterns of dihydropyrimidines which have found use as nucleotide exchange factor inhibitors.
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Affiliation(s)
- Miao Yang
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, United States
| | - Shannon J. Odelberg
- Department of Medicine, Cardiology Division, University of Utah, Salt Lake City, UT 84132, United States
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT 84112, United States
- Navigen Inc., Salt Lake City, UT 84108, United States
| | | | - Dean Y. Li
- Department of Medicine, Cardiology Division, University of Utah, Salt Lake City, UT 84132, United States
- Program in Molecular Medicine, University of Utah, Salt Lake City, UT 84112, United States
- Department of Oncology, University of Utah, Salt Lake City, UT 84112, United States
| | - Ryan E. Looper
- Department of Chemistry, University of Utah, Salt Lake City, UT 84112, United States
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Allaire PD, Seyed Sadr M, Chaineau M, Seyed Sadr E, Konefal S, Fotouhi M, Maret D, Ritter B, Del Maestro RF, McPherson PS. Interplay between Rab35 and Arf6 controls cargo recycling to coordinate cell adhesion and migration. J Cell Sci 2012; 126:722-31. [PMID: 23264734 DOI: 10.1242/jcs.112375] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Cells inversely adjust the plasma membrane levels of integrins and cadherins during cell migration and cell-cell adhesion but the regulatory mechanisms that coordinate these trafficking events remain unknown. Here, we demonstrate that the small GTPase Rab35 maintains cadherins at the cell surface to promote cell-cell adhesion. Simultaneously, Rab35 supresses the activity of the GTPase Arf6 to downregulate an Arf6-dependent recycling pathway for β1-integrin and EGF receptors, resulting in inhibition of cell migration and attenuation of signaling downstream of these receptors. Importantly, the phenotypes of decreased cell adhesion and increased cell migration observed following Rab35 knock down are consistent with the epithelial-mesenchymal transition, a feature of invasive cancer cells, and we show that Rab35 expression is suppressed in a subset of cancers characterized by Arf6 hyperactivity. Our data thus identify a key molecular mechanism that efficiently coordinates the inverse intracellular sorting and cell surface levels of cadherin and integrin receptors for cell migration and differentiation.
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Affiliation(s)
- Patrick D Allaire
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
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Knizhnik AV, Kovaleva OV, Komelkov AV, Trukhanova LS, Rybko VA, Zborovskaya IB, Tchevkina EM. Arf6 promotes cell proliferation via the PLD-mTORC1 and p38MAPK pathways. J Cell Biochem 2012; 113:360-71. [PMID: 21928324 DOI: 10.1002/jcb.23362] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The small G-protein ADP-ribosylation factor 6 (Arf6) belongs to the Ras GTPases superfamily and is mostly known for its actin remodeling functions and involvement in the processes of plasma membrane reorganization and vesicular transport. The majority of data indicates that Arf6 contributes to cancer progression through activation of cell motility and invasion. Alternatively, we found that the expression of a wild-type or a constitutively active Arf6 does not influence tumor cell motility and invasion but instead significantly stimulates cell proliferation and activates phospholipase D (PLD). Conversely the expression of a mutant Arf6 (Arf6N48I), that is, unable to interact with PLD has no effect on proliferation but promotes motility, invasion, and matrix degradation by uPA extracellular proteinase. Studying the mechanisms of Arf6-dependent stimulation of cell proliferation, we found some signaling pathways contributing to Arf6 promitogenic activity. Namely, we showed that Arf6 in a PLD-mTORC1-dependent manner activates S6K1 kinase, a well-known regulator of mitogen-stimulated translation initiation. Furthermore, we demonstrated an Arf6-dependent phosphorylation of mTORC1 downstream targets, 4E-BP1 and ribosomal S6 protein, confirming an existence of Arf6-PLD-mTORC1-S6K1/4E-BP1 signaling pathway and also demonstrated its impact on proliferation stimulation. Next, we found that Arf6 activation potentiates Erk1/2 and p38MAP kinases phosphorylation. Surprisingly, p38 opposite to Erk1/2 significantly contributes to Arf6-dependent proliferation increase promoting S6 ribosomal protein phosphorylation at Ser235/236 residues. Therefore, we demonstrated Arf6 proliferation stimulating activity and revealed PLD-mTORC1 and p38MAP kinase as Arf6 partners mediating promitogenic activity. These results highlight a new aspect of Arf6 functioning in cancer cell biology.
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Affiliation(s)
- Anna V Knizhnik
- Institute of Carcinogenesis, Department of Oncogenes Regulation, NN Blokhin Russian Cancer Research Center, Kashirskoye Shosse 24, 115478 Moscow, Russia
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25
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Hu Z, Du J, Yang L, Zhu Y, Yang Y, Zheng D, Someya A, Gu L, Lu X. GEP100/Arf6 is required for epidermal growth factor-induced ERK/Rac1 signaling and cell migration in human hepatoma HepG2 cells. PLoS One 2012; 7:e38777. [PMID: 22701712 PMCID: PMC3372492 DOI: 10.1371/journal.pone.0038777] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 05/10/2012] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Epidermal growth factor (EGF) signaling is implicated in the invasion and metastasis of hepatoma cells. However, the signaling pathways for EGF-induced motility of hepatoma cells remain undefined. METHODOLOGY/PRINCIPAL FINDINGS We found that EGF dose-dependently stimulated the migration of human hepatoma cells HepG2, with the maximal effect at 10 ng/mL. Additionally, EGF increased Arf6 activity, and ectopic expression of Arf6 T27N, a dominant negative Arf6 mutant, largely abolish EGF-induced cell migration. Blocking GEP100 with GEP100 siRNA or GEP100-△PH, a pleckstrin homology (PH) domain deletion mutant of GEP100, blocked EGF-induced Arf6 activity and cell migration. EGF also increased ERK and Rac1 activity. Ectopic expression GEP100 siRNA, GEP100-△PH, or Arf6-T27N suppressed EGF-induced ERK and Rac1 activity. Furthermore, blocking ERK signaling with its inhibitor U0126 remarkably inhibited both EGF-induced Rac1 activation as well as cell migration, and ectopic expression of inactive mutant form of Rac1 (Rac1-T17N) also largely abolished EGF-induced cell migration. CONCLUSIONS/SIGNIFICANCE Taken together, this study highlights the function of the PH domain of GEP100 and its regulated Arf6/ERK/Rac1 signaling cascade in EGF-induced hepatoma cell migration. These findings could provide a rationale for designing new therapy based on inhibition of hepatoma metastasis.
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Affiliation(s)
- ZhenZhen Hu
- Department of Physiology, Nanjing Medical University, Nanjing, China
- Department of Pediatrics, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Jun Du
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Ling Yang
- Department of Cardiology, The Third Affiliated Hospital of Suzhou University, Suzhou, China
| | - YiChao Zhu
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Yu Yang
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - DaTong Zheng
- Department of Pediatrics, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Akimasa Someya
- Department of Host Defense and Biochemical Research, Juntendo University School of Medicine, Tokyo, Japan
| | - Luo Gu
- Cancer Center, Nanjing Medical University, Nanjing, China
- * E-mail: (LG); (XL)
| | - Xiang Lu
- Department of Geriatrics, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, China
- * E-mail: (LG); (XL)
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26
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Bill A, Blockus H, Stumpfe D, Bajorath J, Schmitz A, Famulok M. A homogeneous fluorescence resonance energy transfer system for monitoring the activation of a protein switch in real time. J Am Chem Soc 2011; 133:8372-9. [PMID: 21517092 DOI: 10.1021/ja202513s] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A homogeneous fluorescence resonance energy transfer (FRET) system for the real-time monitoring of exchange factor-catalyzed activation of a ras-like small GTPase is described. The underlying design is based on supramolecular template effects exerted by protein-protein interactions between the GTPase adenosine diphosphate ribosylation factor (ARF) and its effector protein GGA3. The GTPase is activated when bound to guanosine triphosphate (GTP) and switched off in its guanosine diphosphate (GDP)-bound state. Both states are accompanied by severe conformational changes that are recognized by GGA3, which only binds the GTPase "on" state. GDP-to-GTP exchange, i.e., GTPase activation, is catalyzed by the guanine nucleotide exchange factor cytohesin-2. When GGA3 and the GTPase ARF1 are labeled with thoroughly selected FRET probes, with simultaneous recording of the fluorescence of an internal tryptophan residue in ARF1, the conformational changes during the activation of the GTPase can be monitored in real time. We applied the FRET system to a multiplex format that allows the simultaneous identification and distinction of small-molecule inhibitors that interfere with the cytohesin-catalyzed ARF1 activation and/or with the interaction between activated ARF1-GTP and GGA3. By screening a library of potential cytohesin inhibitors, predicted by in silico modeling, we identified new inhibitors for the cytohesin-catalyzed GDP/GTP exchange on ARF1 and verified their increased potency in a cell proliferation assay.
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Affiliation(s)
- Anke Bill
- LIMES Institute, Chemical Biology and Medicinal Chemistry Unit, c/o Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany
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27
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Knizhnik AV, Kovaleva OV, Laktionov KK, Mochalnikova VV, Komelkov AV, Tchevkina EM, Zborovskaya IB. Arf6, RalA, and BIRC5 protein expression in nonsmall cell lung cancer. Mol Biol 2011. [DOI: 10.1134/s0026893310061032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Bhanot H, Young AM, Overmeyer JH, Maltese WA. Induction of nonapoptotic cell death by activated Ras requires inverse regulation of Rac1 and Arf6. Mol Cancer Res 2010; 8:1358-74. [PMID: 20713492 DOI: 10.1158/1541-7786.mcr-10-0090] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Methuosis is a unique form of nonapoptotic cell death triggered by alterations in the trafficking of clathrin-independent endosomes, ultimately leading to extreme vacuolization and rupture of the cell. Methuosis can be induced in glioblastoma cells by expression of constitutively active Ras. This study identifies the small GTPases, Rac1 and Arf6, and the Arf6 GTPase-activating protein, GIT1, as key downstream components of the signaling pathway underlying Ras-induced methuosis. The extent to which graded expression of active H-Ras(G12V) triggers cytoplasmic vacuolization correlates with the amount of endogenous Rac1 in the active GTP state. Blocking Rac1 activation with the specific Rac inhibitor, EHT 1864, or coexpression of dominant-negative Rac1(T17N), prevents the accumulation of vacuoles induced by H-Ras(G12V). Coincident with Rac1 activation, H-Ras(G12V) causes a decrease in the amount of active Arf6, a GTPase that functions in the recycling of clathrin-independent endosomes. The effect of H-Ras(G12V) on Arf6 is blocked by EHT 1864, indicating that the decrease in Arf6-GTP is directly linked to the activation of Rac1. Constitutively active Rac1(G12V) interacts with GIT1 in immunoprecipitation assays. Ablation of GIT1 by short hairpin RNA prevents the decrease in active Arf6, inhibits vacuolization, and prevents loss of cell viability in cells expressing Rac1(G12V). Together, the results suggest that perturbations of endosome morphology associated with Ras-induced methuosis are due to downstream activation of Rac1 combined with reciprocal inactivation of Arf6. The latter seems to be mediated through Rac1 stimulation of GIT1. Further insights into this pathway could suggest opportunities for the induction of methuosis in cancers that are resistant to apoptotic cell death.
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Affiliation(s)
- Haymanti Bhanot
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine, Toledo, Ohio 43614, USA
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29
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Abstract
The small GTP-binding protein Arf6 is known to be an important regulator of the actin cytoskeleton and of cell motility associated with metastasis. A recent study identifies yet another role for Arf6 in metastasis - as a regulator of plasma-membrane-derived microvesicle release.
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Affiliation(s)
- Richard T Premont
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
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