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Wang XW, Tang YX, Li FX, Wang JL, Yao GP, Zeng DT, Tang YL, Chi BT, Su QY, Huang LQ, Qin DY, Chen G, Feng ZB, He RQ. Clinical significance of upregulated Rho GTPase activating protein 12 causing resistance to tyrosine kinase inhibitors in hepatocellular carcinoma. World J Gastrointest Oncol 2024; 16:4244-4263. [DOI: 10.4251/wjgo.v16.i10.4244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Revised: 08/17/2024] [Accepted: 09/06/2024] [Indexed: 09/26/2024] Open
Abstract
BACKGROUND Hepatocellular carcinoma (HCC) is a major health challenge with high incidence and poor survival rates in China. Systemic therapies, particularly tyrosine kinase inhibitors (TKIs), are the first-line treatment for advanced HCC, but resistance is common. The Rho GTPase family member Rho GTPase activating protein 12 (ARHGAP12), which regulates cell adhesion and invasion, is a potential therapeutic target for overcoming TKI resistance in HCC. However, no studies on the expression of ARHGAP12 in HCC and its role in resistance to TKIs have been reported.
AIM To unveil the expression of ARHGAP12 in HCC, its role in TKI resistance and its potential associated pathways.
METHODS This study used single-cell RNA sequencing (scRNA-seq) to evaluate ARHGAP12 mRNA levels and explored its mechanisms through enrichment analysis. CellChat was used to investigate focal adhesion (FA) pathway regulation. We integrated bulk RNA data (RNA-seq and microarray), immunohistochemistry and proteomics to analyze ARHGAP12 mRNA and protein levels, correlating with clinical outcomes. We assessed ARHGAP12 expression in TKI-resistant HCC, integrated conventional HCC to explore its mechanism, identified intersecting FA pathway genes with scRNA-seq data and evaluated its response to TKI and immunotherapy.
RESULTS ARHGAP12 mRNA was found to be highly expressed in malignant hepatocytes and to regulate FA. In malignant hepatocytes in high-score FA groups, MDK-[integrin alpha 6 (ITGA6) + integrin β-1 (ITGB1)] showed specificity in ligand-receptor interactions. ARHGAP12 mRNA and protein were upregulated in bulk RNA, immunohistochemistry and proteomics, and higher expression was associated with a worse prognosis. ARHGAP12 was also found to be a TKI resistance gene that regulated the FA pathway. ITGB1 was identified as a crossover gene in the FA pathway in both scRNA-seq and bulk RNA. High expression of ARHGAP12 was associated with adverse reactions to sorafenib, cabozantinib and regorafenib, but not to immunotherapy.
CONCLUSION ARHGAP12 expression is elevated in HCC and TKI-resistant HCC, and its regulatory role in FA may underlie the TKI-resistant phenotype.
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Affiliation(s)
- Xiao-Wei Wang
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Yu-Xing Tang
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Fu-Xi Li
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Jia-Le Wang
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Gao-Peng Yao
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Da-Tong Zeng
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China
- Department of Pathology, Red Cross Hospital of Yulin City, Yulin 537000, Guangxi Zhuang Autonomous Region, China
| | - Yu-Lu Tang
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Bang-Teng Chi
- Department of Medical Oncology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Qin-Yan Su
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Lin-Qing Huang
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Di-Yuan Qin
- Department of Computer Science and Technology, School of Computer and Electronic Information, Guangxi University, Nanning 530004, Guangxi Zhuang Autonomous Region, China
| | - Gang Chen
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Zhen-Bo Feng
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China
| | - Rong-Quan He
- Department of Medical Oncology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China
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Fei H, Shi X, Sun D, Yang H, Wang D, Li K, Si X, Hu W. Integrated analysis identified the role of three family members of ARHGAP in pancreatic adenocarcinoma. Sci Rep 2024; 14:11790. [PMID: 38783033 PMCID: PMC11116390 DOI: 10.1038/s41598-024-62577-z] [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: 10/02/2023] [Accepted: 05/20/2024] [Indexed: 05/25/2024] Open
Abstract
The Rho GTPase activating protein family (ARHGAPs) is expressed in pancreatic adenocarcinoma (PAAD) but its function is unclear. The aim of this study was to explore the role and potential clinical value of ARHGAPs in PAAD. Using TCGA and GEO databases to analyze expression of ARHGAPs in PAAD and normal tissues. Survival curve was drawn by Kaplan-Meier. ARHGAPs were integrated analyzed by GEPIA2, TIMER, UCLCAN, cBioPortal and R language. Protein level and prognostic value were evaluated via IHC staining or survival analysis. We totally identify 18 differentially expressed (DE) ARHGAPs in PAAD. Among the 18 DE genes, 8 were positively correlated with tumor grade; abnorrmal expression of 5 was positively correlated with copy number variation; expression of 4 was positively correlated with promoter hypomethylation. Multivariate Cox regression identified ARHGAP5, ARHGAP11A, and ARHGAP12 as independent prognostic factors of PAAD. The function of ARHGAPs was mainly related to GTPase activity and signaling, axon guidance, proteoglycans in cancer and focal adhesion. Expression of 7 ARHGAPs was strongly correlated with immune infiltration. Immunohistochemistry showed increased protein levels of ARHGAP5, ARHGAP11A, and ARHGAP12 in PAAD tissues. Survival analysis confirmed a negative correlation between ARHGAP5, ARHGAP11A, and ARHGAP12 expression and patient prognosis. Multivariate Cox regression proved ARHGAP5, ARHGAP11A, and ARHGAP12 could serve as independent prognostic indicators for PAAD. Finally, this study verified ARHGAP5, ARHGAP11A, and ARHGAP12 as independent prognostic factors in PAAD, suggesting their significance for the diagnosis and treatment of PAAD.
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Affiliation(s)
- Haoran Fei
- Department of Hepatobiliary Surgery, The First People's Hospital of Lianyungang, The First Affiliated Hospital of Kangda College of Nanjing Medical University, Lianyungang, 222000, Jiangsu, China
- Jinzhou Medical University, Jinzhou, 121001, Liaoning, China
| | - Xiao Shi
- Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, College of Pharmacy, Jiangsu Ocean University, Lianyungang, 222005, Jiangsu, China
| | - Dan Sun
- Department of Hepatobiliary Surgery, The First People's Hospital of Lianyungang, The First Affiliated Hospital of Kangda College of Nanjing Medical University, Lianyungang, 222000, Jiangsu, China
- Jinzhou Medical University, Jinzhou, 121001, Liaoning, China
| | - Haishen Yang
- Department of Hepatobiliary Surgery, The First People's Hospital of Lianyungang, The First Affiliated Hospital of Kangda College of Nanjing Medical University, Lianyungang, 222000, Jiangsu, China
| | - Dali Wang
- Department of Hepatobiliary Surgery, The First People's Hospital of Lianyungang, The First Affiliated Hospital of Kangda College of Nanjing Medical University, Lianyungang, 222000, Jiangsu, China
| | - Kai Li
- Department of Hepatobiliary Surgery, The First People's Hospital of Lianyungang, The First Affiliated Hospital of Kangda College of Nanjing Medical University, Lianyungang, 222000, Jiangsu, China
| | - Xinxin Si
- Jiangsu Key Laboratory of Marine Pharmaceutical Compound Screening, College of Pharmacy, Jiangsu Ocean University, Lianyungang, 222005, Jiangsu, China.
| | - Wei Hu
- Department of Hepatobiliary Surgery, The First People's Hospital of Lianyungang, The First Affiliated Hospital of Kangda College of Nanjing Medical University, Lianyungang, 222000, Jiangsu, China.
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3
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Fixing the GAP: the role of RhoGAPs in cancer. Eur J Cell Biol 2022; 101:151209. [DOI: 10.1016/j.ejcb.2022.151209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 01/29/2022] [Accepted: 02/08/2022] [Indexed: 12/12/2022] Open
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Lung adenocarcinoma and lung squamous cell carcinoma cancer classification, biomarker identification, and gene expression analysis using overlapping feature selection methods. Sci Rep 2021; 11:13323. [PMID: 34172784 PMCID: PMC8233431 DOI: 10.1038/s41598-021-92725-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 06/14/2021] [Indexed: 02/06/2023] Open
Abstract
Lung cancer is one of the deadliest cancers in the world. Two of the most common subtypes, lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), have drastically different biological signatures, yet they are often treated similarly and classified together as non-small cell lung cancer (NSCLC). LUAD and LUSC biomarkers are scarce, and their distinct biological mechanisms have yet to be elucidated. To detect biologically relevant markers, many studies have attempted to improve traditional machine learning algorithms or develop novel algorithms for biomarker discovery. However, few have used overlapping machine learning or feature selection methods for cancer classification, biomarker identification, or gene expression analysis. This study proposes to use overlapping traditional feature selection or feature reduction techniques for cancer classification and biomarker discovery. The genes selected by the overlapping method were then verified using random forest. The classification statistics of the overlapping method were compared to those of the traditional feature selection methods. The identified biomarkers were validated in an external dataset using AUC and ROC analysis. Gene expression analysis was then performed to further investigate biological differences between LUAD and LUSC. Overall, our method achieved classification results comparable to, if not better than, the traditional algorithms. It also identified multiple known biomarkers, and five potentially novel biomarkers with high discriminating values between LUAD and LUSC. Many of the biomarkers also exhibit significant prognostic potential, particularly in LUAD. Our study also unraveled distinct biological pathways between LUAD and LUSC.
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Fan C, Qu H, Xiong F, Tang Y, Tang T, Zhang L, Mo Y, Li X, Guo C, Zhang S, Gong Z, Li Z, Xiang B, Deng H, Zhou M, Liao Q, Zhou Y, Li X, Li Y, Li G, Wang F, Zeng Z. CircARHGAP12 promotes nasopharyngeal carcinoma migration and invasion via ezrin-mediated cytoskeletal remodeling. Cancer Lett 2020; 496:41-56. [PMID: 32931883 DOI: 10.1016/j.canlet.2020.09.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/27/2020] [Accepted: 09/07/2020] [Indexed: 02/07/2023]
Abstract
An increasing number of studies have shown that circular RNAs (circRNAs) play important roles in malignant tumor initiation and progression; however, many circRNAs are yet unidentified, and the role of circRNAs in nasopharyngeal carcinoma (NPC) is unclear. Using RNA sequencing, we discovered a novel circRNA, termed circARHGAP12, that was processed from the pre-mRNA of the ARHGAP12 gene. CircARHGAP12 was significantly upregulated in NPC tissues and cell lines and promoted NPC cell migration and invasion. Overexpression or knockdown experiments revealed that circARHGAP12 regulates the expression of cytoskeletal remodeling-related proteins EZR, TPM3, and RhoA. CircARHGAP12 was found to bind directly to the 3' UTR of EZR mRNA and promote its stability; moreover, EZR protein interacted with TPM3 and RhoA and formed a complex to promote NPC cell invasion and metastasis. This study identified the novel circRNA circARHGAP12, characterized its biological function and mechanism, and increased our understanding of circRNAs in NPC pathogenesis. In particular, circARHGAP12 was found to promote the malignant biological phenotype of NPC via cytoskeletal remodeling, thus providing a clue for targeted therapy of NPC.
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Affiliation(s)
- Chunmei Fan
- NHC Key Laboratory of Carcinogenesis, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, PR China; The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medicine Sciences, Central South University, Changsha, Hunan, PR China; Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Disease Genome Research Center, The Third Xiangya Hospital, Central South University, Changsha, Hunan, PR China
| | - Hongke Qu
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medicine Sciences, Central South University, Changsha, Hunan, PR China
| | - Fang Xiong
- Department of Stomatology, Xiangya Hospital, Central South University, Changsha, Hunan, PR China
| | - Yanyan Tang
- NHC Key Laboratory of Carcinogenesis, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, PR China
| | - Ting Tang
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medicine Sciences, Central South University, Changsha, Hunan, PR China
| | - Lishen Zhang
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medicine Sciences, Central South University, Changsha, Hunan, PR China
| | - Yongzhen Mo
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medicine Sciences, Central South University, Changsha, Hunan, PR China
| | - Xiayu Li
- Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Disease Genome Research Center, The Third Xiangya Hospital, Central South University, Changsha, Hunan, PR China
| | - Can Guo
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medicine Sciences, Central South University, Changsha, Hunan, PR China
| | - Shanshan Zhang
- Department of Stomatology, Xiangya Hospital, Central South University, Changsha, Hunan, PR China
| | - Zhaojian Gong
- Department of Oral and Maxillofacial Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan, PR China
| | - Zheng Li
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medicine Sciences, Central South University, Changsha, Hunan, PR China
| | - Bo Xiang
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medicine Sciences, Central South University, Changsha, Hunan, PR China
| | - Hao Deng
- Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Disease Genome Research Center, The Third Xiangya Hospital, Central South University, Changsha, Hunan, PR China
| | - Ming Zhou
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medicine Sciences, Central South University, Changsha, Hunan, PR China
| | - Qianjin Liao
- NHC Key Laboratory of Carcinogenesis, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, PR China
| | - Yujuan Zhou
- NHC Key Laboratory of Carcinogenesis, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, PR China
| | - Xiaoling Li
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medicine Sciences, Central South University, Changsha, Hunan, PR China
| | - Yong Li
- Department of Medicine, Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Guiyuan Li
- NHC Key Laboratory of Carcinogenesis, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, PR China; The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medicine Sciences, Central South University, Changsha, Hunan, PR China; Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Disease Genome Research Center, The Third Xiangya Hospital, Central South University, Changsha, Hunan, PR China
| | - Fuyan Wang
- NHC Key Laboratory of Carcinogenesis, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, PR China; The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medicine Sciences, Central South University, Changsha, Hunan, PR China.
| | - Zhaoyang Zeng
- NHC Key Laboratory of Carcinogenesis, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, PR China; The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Cancer Research Institute and School of Basic Medicine Sciences, Central South University, Changsha, Hunan, PR China; Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Disease Genome Research Center, The Third Xiangya Hospital, Central South University, Changsha, Hunan, PR China.
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6
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Humphries BA, Wang Z, Yang C. MicroRNA Regulation of the Small Rho GTPase Regulators-Complexities and Opportunities in Targeting Cancer Metastasis. Cancers (Basel) 2020; 12:E1092. [PMID: 32353968 PMCID: PMC7281527 DOI: 10.3390/cancers12051092] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/24/2020] [Accepted: 04/25/2020] [Indexed: 02/07/2023] Open
Abstract
The small Rho GTPases regulate important cellular processes that affect cancer metastasis, such as cell survival and proliferation, actin dynamics, adhesion, migration, invasion and transcriptional activation. The Rho GTPases function as molecular switches cycling between an active GTP-bound and inactive guanosine diphosphate (GDP)-bound conformation. It is known that Rho GTPase activities are mainly regulated by guanine nucleotide exchange factors (RhoGEFs), GTPase-activating proteins (RhoGAPs), GDP dissociation inhibitors (RhoGDIs) and guanine nucleotide exchange modifiers (GEMs). These Rho GTPase regulators are often dysregulated in cancer; however, the underlying mechanisms are not well understood. MicroRNAs (miRNAs), a large family of small non-coding RNAs that negatively regulate protein-coding gene expression, have been shown to play important roles in cancer metastasis. Recent studies showed that miRNAs are capable of directly targeting RhoGAPs, RhoGEFs, and RhoGDIs, and regulate the activities of Rho GTPases. This not only provides new evidence for the critical role of miRNA dysregulation in cancer metastasis, it also reveals novel mechanisms for Rho GTPase regulation. This review summarizes recent exciting findings showing that miRNAs play important roles in regulating Rho GTPase regulators (RhoGEFs, RhoGAPs, RhoGDIs), thus affecting Rho GTPase activities and cancer metastasis. The potential opportunities and challenges for targeting miRNAs and Rho GTPase regulators in treating cancer metastasis are also discussed. A comprehensive list of the currently validated miRNA-targeting of small Rho GTPase regulators is presented as a reference resource.
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Affiliation(s)
- Brock A. Humphries
- Center for Molecular Imaging, Department of Radiology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA
| | - Zhishan Wang
- Department of Toxicology and Cancer Biology, College of Medicine, University of Kentucky, 1095 V A Drive, Lexington, KY 40536, USA;
| | - Chengfeng Yang
- Department of Toxicology and Cancer Biology, College of Medicine, University of Kentucky, 1095 V A Drive, Lexington, KY 40536, USA;
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Diring J, Mouilleron S, McDonald NQ, Treisman R. RPEL-family rhoGAPs link Rac/Cdc42 GTP loading to G-actin availability. Nat Cell Biol 2019; 21:845-855. [PMID: 31209295 PMCID: PMC6960015 DOI: 10.1038/s41556-019-0337-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 04/29/2019] [Indexed: 12/29/2022]
Abstract
RPEL proteins, which contain the G-actin-binding RPEL motif, coordinate cytoskeletal processes with actin dynamics. We show that the ArhGAP12- and ArhGAP32-family GTPase-activating proteins (GAPs) are RPEL proteins. We determine the structure of the ArhGAP12/G-actin complex, and show that G-actin contacts the RPEL motif and GAP domain sequences. G-actin inhibits ArhGAP12 GAP activity, and this requires the G-actin contacts identified in the structure. In B16 melanoma cells, ArhGAP12 suppresses basal Rac and Cdc42 activity, F-actin assembly, invadopodia formation and experimental metastasis. In this setting, ArhGAP12 mutants defective for G-actin binding exhibit more effective downregulation of Rac GTP loading following HGF stimulation and enhanced inhibition of Rac-dependent processes, including invadopodia formation. Potentiation or disruption of the G-actin/ArhGAP12 interaction, by treatment with the actin-binding drugs latrunculin B or cytochalasin D, has corresponding effects on Rac GTP loading. The interaction of G-actin with RPEL-family rhoGAPs thus provides a negative feedback loop that couples Rac activity to actin dynamics.
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Affiliation(s)
- Jessica Diring
- Signalling and Transcription Group, The Francis Crick Institute, London, UK
| | - Stephane Mouilleron
- Structural Biology Science Technology Platform, The Francis Crick Institute, London, UK
| | - Neil Q McDonald
- Signalling and Structural Biology Group, The Francis Crick Institute, London, UK
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, London, UK
| | - Richard Treisman
- Signalling and Transcription Group, The Francis Crick Institute, London, UK.
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Comprehensive Profiling of Primary and Metastatic ccRCC Reveals a High Homology of the Metastases to a Subregion of the Primary Tumour. Cancers (Basel) 2019; 11:cancers11060812. [PMID: 31212796 PMCID: PMC6628027 DOI: 10.3390/cancers11060812] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 12/19/2022] Open
Abstract
While intratumour genetic heterogeneity of primary clear cell renal cell carcinoma (ccRCC) is well characterized, the genomic profiles of metastatic ccRCCs are seldom studied. We profiled the genomes and transcriptomes of a primary tumour and matched metastases to better understand the evolutionary processes that lead to metastasis. In one ccRCC patient, four regions of the primary tumour, one region of the thrombus in the inferior vena cava, and four lung metastases (including one taken after pegylated (PEG)-interferon therapy) were analysed separately. Each sample was analysed for copy number alterations and somatic mutations by whole exome sequencing. We also evaluated gene expression profiles for this patient and 15 primary tumour and 15 metastasis samples from four additional patients. Copy number profiles of the index patient showed two distinct subgroups: one consisted of three primary tumours with relatively minor copy number changes, the other of a primary tumour, the thrombus, and the lung metastases, all with a similar copy number pattern and tetraploid-like characteristics. Somatic mutation profiles indicated parallel clonal evolution with similar numbers of private mutations in each primary tumour and metastatic sample. Expression profiling of the five patients revealed significantly changed expression levels of 57 genes between primary tumours and metastases, with enrichment in the extracellular matrix cluster. The copy number profiles suggest a punctuated evolution from a subregion of the primary tumour. This process, which differentiated the metastases from the primary tumours, most likely occurred rapidly, possibly even before metastasis formation. The evolutionary patterns we deduced from the genomic alterations were also reflected in the gene expression profiles.
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Lemoine L, Sugarbaker P, Van der Speeten K. Pathophysiology of colorectal peritoneal carcinomatosis: Role of the peritoneum. World J Gastroenterol 2016; 22:7692-7707. [PMID: 27678351 PMCID: PMC5016368 DOI: 10.3748/wjg.v22.i34.7692] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/28/2016] [Accepted: 08/01/2016] [Indexed: 02/06/2023] Open
Abstract
Colorectal cancer (CRC) is the third most common cancer and the fourth most common cause of cancer-related death worldwide. Besides the lymphatic and haematogenous routes of dissemination, CRC frequently gives rise to transcoelomic spread of tumor cells in the peritoneal cavity, which ultimately leads to peritoneal carcinomatosis (PC). PC is associated with a poor prognosis and bad quality of life for these patients in their terminal stages of disease. A loco-regional treatment modality for PC combining cytoreductive surgery and hyperthermic intraperitoneal peroperative chemotherapy has resulted in promising clinical results. However, this novel approach is associated with significant morbidity and mortality. A comprehensive understanding of the molecular events involved in peritoneal disease spread is paramount in avoiding unnecessary toxicity. The emergence of PC is the result of a molecular crosstalk between cancer cells and host elements, involving several well-defined steps, together known as the peritoneal metastatic cascade. Individual or clumps of tumor cells detach from the primary tumor, gain access to the peritoneal cavity and become susceptible to the regular peritoneal transport. They attach to the distant peritoneum, subsequently invade the subperitoneal space, where angiogenesis sustains proliferation and enables further metastatic growth. These molecular events are not isolated events but rather a continuous and interdependent process. In this manuscript, we review current data regarding the molecular mechanisms underlying the development of colorectal PC, with a special focus on the peritoneum and the role of the surgeon in peritoneal disease spread.
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Charbonnier A, Sannier G, Dupré S. [Mission phagocytosis: how to fit the weapons to the target size]. Med Sci (Paris) 2016; 32:587-9. [PMID: 27406768 DOI: 10.1051/medsci/20163206021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Gérémy Sannier
- M1 Biologie Santé, Université Paris-Saclay, 91405 Orsay, France
| | - Sophie Dupré
- Laboratoire de chimie physique, UMR8000, CNRS, université Paris-Saclay, 91405 Orsay, France
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11
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Banh RS, Iorio C, Marcotte R, Xu Y, Cojocari D, Rahman AA, Pawling J, Zhang W, Sinha A, Rose CM, Isasa M, Zhang S, Wu R, Virtanen C, Hitomi T, Habu T, Sidhu SS, Koizumi A, Wilkins SE, Kislinger T, Gygi SP, Schofield CJ, Dennis JW, Wouters BG, Neel BG. PTP1B controls non-mitochondrial oxygen consumption by regulating RNF213 to promote tumour survival during hypoxia. Nat Cell Biol 2016; 18:803-813. [PMID: 27323329 PMCID: PMC4936519 DOI: 10.1038/ncb3376] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 05/13/2016] [Indexed: 02/07/2023]
Abstract
Tumours exist in a hypoxic microenvironment and must limit excessive oxygen consumption. Hypoxia-inducible factor (HIF) controls mitochondrial oxygen consumption, but how/if tumours regulate non-mitochondrial oxygen consumption (NMOC) is unknown. Protein-tyrosine phosphatase-1B (PTP1B) is required for Her2/Neu-driven breast cancer (BC) in mice, although the underlying mechanism and human relevance remain unclear. We found that PTP1B-deficient HER2(+) xenografts have increased hypoxia, necrosis and impaired growth. In vitro, PTP1B deficiency sensitizes HER2(+) BC lines to hypoxia by increasing NMOC by α-KG-dependent dioxygenases (α-KGDDs). The moyamoya disease gene product RNF213, an E3 ligase, is negatively regulated by PTP1B in HER2(+) BC cells. RNF213 knockdown reverses the effects of PTP1B deficiency on α-KGDDs, NMOC and hypoxia-induced death of HER2(+) BC cells, and partially restores tumorigenicity. We conclude that PTP1B acts via RNF213 to suppress α-KGDD activity and NMOC. This PTP1B/RNF213/α-KGDD pathway is critical for survival of HER2(+) BC, and possibly other malignancies, in the hypoxic tumour microenvironment.
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Affiliation(s)
- Robert S Banh
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 2M9, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Caterina Iorio
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Richard Marcotte
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Yang Xu
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 2M9, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Dan Cojocari
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 2M9, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Anas Abdel Rahman
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada
- Department of Genetics, Research Center, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Judy Pawling
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada
| | - Wei Zhang
- Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Ankit Sinha
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 2M9, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Christopher M Rose
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Marta Isasa
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Shuang Zhang
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Medical Center, New York University, New York, NY 10016, USA
| | - Ronald Wu
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 2M9, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Carl Virtanen
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Toshiaki Hitomi
- Department of Health and Environmental Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Toshiyuki Habu
- Department of Radiation System Biology, Institute of Radiation Biology Center, Kyoto University, Kyoto, Japan
| | - Sachdev S Sidhu
- Donnelly Centre for Cellular and Biomolecular Research, Banting and Best Department of Medical Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Akio Koizumi
- Department of Health and Environmental Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Sarah E Wilkins
- Chemistry Research Laboratory, Oxford University, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Thomas Kislinger
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 2M9, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | | | - James W Dennis
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, M5G 1X5, Canada
| | - Bradly G Wouters
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 2M9, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
| | - Benjamin G Neel
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, M5G 1L7, Canada
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Medical Center, New York University, New York, NY 10016, USA
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12
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Yi F, Kong R, Ren J, Zhu L, Lou J, Wu JY, Feng W. Noncanonical Myo9b-RhoGAP Accelerates RhoA GTP Hydrolysis by a Dual-Arginine-Finger Mechanism. J Mol Biol 2016; 428:3043-57. [PMID: 27363609 DOI: 10.1016/j.jmb.2016.06.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 06/17/2016] [Accepted: 06/19/2016] [Indexed: 10/21/2022]
Abstract
The GTP hydrolysis activities of Rho GTPases are stimulated by GTPase-activating proteins (GAPs), which contain a RhoGAP domain equipped with a characteristic arginine finger and an auxiliary asparagine for catalysis. However, the auxiliary asparagine is missing in the RhoGAP domain of Myo9b (Myo9b-RhoGAP), a unique motorized RhoGAP that specifically targets RhoA for controlling cell motility. Here, we determined the structure of Myo9b-RhoGAP in complex with GDP-bound RhoA and magnesium fluoride. Unexpectedly, Myo9b-RhoGAP contains two arginine fingers at its catalytic site. The first arginine finger resembles the one within the canonical RhoGAP domains and inserts into the nucleotide-binding pocket of RhoA, whereas the second arginine finger anchors the Switch I loop of RhoA and interacts with the nucleotide, stabilizing the transition state of GTP hydrolysis and compensating for the lack of the asparagine. Mutating either of the two arginine fingers impaired the catalytic activity of Myo9b-RhoGAP and affected the Myo9b-mediated cell migration. Our data indicate that Myo9b-RhoGAP accelerates RhoA GTP hydrolysis by a previously unknown dual-arginine-finger mechanism, which may be shared by other noncanonical RhoGAP domains lacking the auxiliary asparagine.
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Affiliation(s)
- Fengshuang Yi
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruirui Kong
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Jinqi Ren
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Li Zhu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Jizhong Lou
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Jane Y Wu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; Department of Neurology, Center for Genetic Medicine, Lurie Cancer Center, Northwestern University Feinberg School of Medicine, 303 E Superior, Chicago, IL 60611 USA.
| | - Wei Feng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.
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13
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Ba W, Selten MM, van der Raadt J, van Veen H, Li LL, Benevento M, Oudakker AR, Lasabuda RSE, Letteboer SJ, Roepman R, van Wezel RJA, Courtney MJ, van Bokhoven H, Nadif Kasri N. ARHGAP12 Functions as a Developmental Brake on Excitatory Synapse Function. Cell Rep 2016; 14:1355-1368. [PMID: 26854232 DOI: 10.1016/j.celrep.2016.01.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 11/28/2015] [Accepted: 01/09/2016] [Indexed: 12/31/2022] Open
Abstract
The molecular mechanisms that promote excitatory synapse development have been extensively studied. However, the molecular events preventing precocious excitatory synapse development so that synapses form at the correct time and place are less well understood. Here, we report the functional characterization of ARHGAP12, a previously uncharacterized Rho GTPase-activating protein (RhoGAP) in the brain. ARHGAP12 is specifically expressed in the CA1 region of the hippocampus, where it localizes to the postsynaptic compartment of excitatory synapses. ARHGAP12 negatively controls spine size via its RhoGAP activity and promotes, by interacting with CIP4, postsynaptic AMPA receptor endocytosis. Arhgap12 knockdown results in precocious maturation of excitatory synapses, as indicated by a reduction in the proportion of silent synapses. Collectively, our data show that ARHGAP12 is a synaptic RhoGAP that regulates excitatory synaptic structure and function during development.
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Affiliation(s)
- W Ba
- Department of Cognitive Neuroscience, Radboudumc, 6500 HB Nijmegen, the Netherlands; Department of Human Genetics, Radboudumc, 6500 HB Nijmegen, the Netherlands; Donders Institute for Brain, Cognition, and Behaviour, 6525 AJ Nijmegen, the Netherlands
| | - M M Selten
- Department of Cognitive Neuroscience, Radboudumc, 6500 HB Nijmegen, the Netherlands; Department of Human Genetics, Radboudumc, 6500 HB Nijmegen, the Netherlands; Donders Institute for Brain, Cognition, and Behaviour, 6525 AJ Nijmegen, the Netherlands
| | - J van der Raadt
- Department of Human Genetics, Radboudumc, 6500 HB Nijmegen, the Netherlands; Radboud Institute for Molecular Life Sciences, Radboudumc, 6525 GA Nijmegen, the Netherlands
| | - H van Veen
- Donders Institute for Brain, Cognition, and Behaviour, 6525 AJ Nijmegen, the Netherlands; Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, P.O. Box 80082, 30508 TB Utrecht, the Netherlands
| | - L-L Li
- Molecular Signalling Laboratory, Department of Neurobiology, A.I. Virtanen Institute, University of Eastern Finland, Kuopio 70210, Finland
| | - M Benevento
- Department of Cognitive Neuroscience, Radboudumc, 6500 HB Nijmegen, the Netherlands; Department of Human Genetics, Radboudumc, 6500 HB Nijmegen, the Netherlands; Donders Institute for Brain, Cognition, and Behaviour, 6525 AJ Nijmegen, the Netherlands
| | - A R Oudakker
- Department of Cognitive Neuroscience, Radboudumc, 6500 HB Nijmegen, the Netherlands; Department of Human Genetics, Radboudumc, 6500 HB Nijmegen, the Netherlands; Donders Institute for Brain, Cognition, and Behaviour, 6525 AJ Nijmegen, the Netherlands
| | - R S E Lasabuda
- Department of Human Genetics, Radboudumc, 6500 HB Nijmegen, the Netherlands
| | - S J Letteboer
- Department of Human Genetics, Radboudumc, 6500 HB Nijmegen, the Netherlands; Radboud Institute for Molecular Life Sciences, Radboudumc, 6525 GA Nijmegen, the Netherlands
| | - R Roepman
- Department of Human Genetics, Radboudumc, 6500 HB Nijmegen, the Netherlands; Radboud Institute for Molecular Life Sciences, Radboudumc, 6525 GA Nijmegen, the Netherlands
| | - R J A van Wezel
- Donders Institute for Brain, Cognition, and Behaviour, 6525 AJ Nijmegen, the Netherlands; Biomedical Signal and Systems, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, 7500 AE Enschede, the Netherlands
| | - M J Courtney
- Molecular Signalling Laboratory, Department of Neurobiology, A.I. Virtanen Institute, University of Eastern Finland, Kuopio 70210, Finland; Turku Centre for Biotechnology, Abo Akademi University and University of Turku, Turku 20521, Finland
| | - H van Bokhoven
- Department of Cognitive Neuroscience, Radboudumc, 6500 HB Nijmegen, the Netherlands; Department of Human Genetics, Radboudumc, 6500 HB Nijmegen, the Netherlands; Donders Institute for Brain, Cognition, and Behaviour, 6525 AJ Nijmegen, the Netherlands; Radboud Institute for Molecular Life Sciences, Radboudumc, 6525 GA Nijmegen, the Netherlands
| | - N Nadif Kasri
- Department of Cognitive Neuroscience, Radboudumc, 6500 HB Nijmegen, the Netherlands; Department of Human Genetics, Radboudumc, 6500 HB Nijmegen, the Netherlands; Donders Institute for Brain, Cognition, and Behaviour, 6525 AJ Nijmegen, the Netherlands.
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14
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Schlam D, Bagshaw RD, Freeman SA, Collins RF, Pawson T, Fairn GD, Grinstein S. Phosphoinositide 3-kinase enables phagocytosis of large particles by terminating actin assembly through Rac/Cdc42 GTPase-activating proteins. Nat Commun 2015; 6:8623. [PMID: 26465210 PMCID: PMC4634337 DOI: 10.1038/ncomms9623] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 09/11/2015] [Indexed: 02/06/2023] Open
Abstract
Phagocytosis is responsible for the elimination of particles of widely disparate sizes, from large fungi or effete cells to small bacteria. Though superficially similar, the molecular mechanisms involved differ: engulfment of large targets requires phosphoinositide 3-kinase (PI3K), while that of small ones does not. Here, we report that inactivation of Rac and Cdc42 at phagocytic cups is essential to complete internalization of large particles. Through a screen of 62 RhoGAP-family members, we demonstrate that ARHGAP12, ARHGAP25 and SH3BP1 are responsible for GTPase inactivation. Silencing these RhoGAPs impairs phagocytosis of large targets. The GAPs are recruited to large—but not small—phagocytic cups by products of PI3K, where they synergistically inactivate Rac and Cdc42. Remarkably, the prominent accumulation of phosphatidylinositol 3,4,5-trisphosphate characteristic of large-phagosome formation is less evident during phagocytosis of small targets, accounting for the contrasting RhoGAP distribution and the differential requirement for PI3K during phagocytosis of dissimilarly sized particles. Phagocytosis of large (but not small) particles requires PI 3-kinase activity. Here, Schlam et al. show that Rho GTPase-activating proteins are recruited to the phagocytic cup by products of PI 3-kinase, resulting in the local inactivation of Rac and Cdc42 and allowing for the completion of internalization of large particles.
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Affiliation(s)
- Daniel Schlam
- Division of Cell Biology, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G1X8.,Institute of Medical Science, University of Toronto, Faculty of Medicine, 1 King's College Circle, Toronto, Ontario, Canada M5S1A8
| | - Richard D Bagshaw
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario, Canada M5G1X5
| | - Spencer A Freeman
- Division of Cell Biology, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G1X8
| | - Richard F Collins
- Division of Cell Biology, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G1X8
| | - Tony Pawson
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario, Canada M5G1X5
| | - Gregory D Fairn
- Institute of Medical Science, University of Toronto, Faculty of Medicine, 1 King's College Circle, Toronto, Ontario, Canada M5S1A8.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, 209 Victoria Street, Toronto, Ontario, Canada M5B1T8
| | - Sergio Grinstein
- Division of Cell Biology, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada M5G1X8.,Institute of Medical Science, University of Toronto, Faculty of Medicine, 1 King's College Circle, Toronto, Ontario, Canada M5S1A8.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, 209 Victoria Street, Toronto, Ontario, Canada M5B1T8
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15
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Contreras-Galindo R, Kaplan MH, Dube D, Gonzalez-Hernandez MJ, Chan S, Meng F, Dai M, Omenn GS, Gitlin SD, Markovitz DM. Human Endogenous Retrovirus Type K (HERV-K) Particles Package and Transmit HERV-K-Related Sequences. J Virol 2015; 89:7187-201. [PMID: 25926654 PMCID: PMC4473553 DOI: 10.1128/jvi.00544-15] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 04/25/2015] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED Human endogenous retroviruses (HERV) make up 8% of the human genome. While the youngest of these retroviruses, HERV-K(HML-2), termed HK2, is able to code for all viral proteins and produce virus-like particles, it is not known if these virus particles package and transmit HK2-related sequences. Here, we analyzed the capacity of HK2 for packaging and transmitting HK2 sequences. We created an HK2 probe, termed Bogota, which can be packaged into HK2 viruses, and transfected it into cells that make HK2 particles. Supernatants of the transfected cells, which contained HK2 viral particles, then were added to target cells, and the transmissibility of the HK2 Bogota reporter was tracked by G418 resistance. Our studies revealed that contemporary HK2 virions produced by some teratocarcinoma and breast cancer cell lines, as well as by peripheral blood lymphocytes from lymphoma patients, can package HK2 Bogota probes, and these viruses transmitted these probes to other cells. After transmission, HK2 Bogota transcripts undergo reverse transcription, a step impaired by antiretroviral agents or by introduction of mutations into the probe sequences required for reverse transcription. HK2 viruses were more efficiently transmitted in the presence of HK2 Rec or HIV-1 Tat and Vif. Transmitted Bogota probes formed episomes but did not integrate into the cellular genome. Resistance to integration might explain the relatively low number of HK2 insertions that were acquired during the last 25 million years of evolution. Whether transient transmission of modern HK2 sequences, which encode two putative oncoproteins, can lead to disease remains to be studied. IMPORTANCE Retroviruses invaded the genome of human ancestors over the course of millions of years, yet these viruses generally have been inactivated during evolution, with only remnants of these infectious sequences remaining in the human genome. One of these viruses, termed HK2, still is capable of producing virus particles, although these particles have been regarded as being noninfectious. Using a genetic probe derived from HK2, we have discovered that HK2 viruses produced in modern humans can package HK2 sequences and transmit them to various other cells. Furthermore, the genetic sequences packaged in HK2 undergo reverse transcription. The transmitted probe circularized in the cell and failed to integrate into the cellular genome. These findings suggest that modern HK2 viruses can package viral RNA and transmit it to other cells. Contrary to previous views, we provide evidence of an extracellular viral phase of modern HK2 viruses. We have no evidence of sustained, spreading infection.
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Affiliation(s)
| | - Mark H Kaplan
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Derek Dube
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Marta J Gonzalez-Hernandez
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA Programs in Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Susana Chan
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Fan Meng
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan, USA Department of Psychiatry, University of Michigan, Ann Arbor, Michigan, USA
| | - Manhong Dai
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Gilbert S Omenn
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, USA Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA Comprehensive Cancer Center, University of Michigan, Ann Arbor, Michigan, USA
| | - Scott D Gitlin
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA Comprehensive Cancer Center, University of Michigan, Ann Arbor, Michigan, USA Veteran Affairs Health System, Ann Arbor, Michigan, USA
| | - David M Markovitz
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA Programs in Immunology, University of Michigan, Ann Arbor, Michigan, USA Programs in Cancer Biology, University of Michigan, Ann Arbor, Michigan, USA Programs in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan, USA
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16
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Nakahara S, Tsutsumi K, Zuinen T, Ohta Y. FilGAP, a Rho–ROCK-regulated GAP for Rac, controls adherens junctions in MDCK cells. J Cell Sci 2015; 128:2047-56. [DOI: 10.1242/jcs.160192] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 04/14/2015] [Indexed: 01/05/2023] Open
Abstract
ABSTRACT
Rho family small GTPases are essential for the formation of adherens junctions in epithelial cells. Here, we found that FilGAP (also known as ARHGAP24), a Rac-specific Rho GTPase-activating protein, promoted the formation of adherens junctions in Madin–Darby canine kidney (MDCK) cells. Knockdown of FilGAP by siRNA stimulated the disassembly and migration of MDCK cells induced by hepatocyte growth factor (HGF). By contrast, forced expression of FilGAP induced accumulation of E-cadherin at adherens junctions. Endogenous FilGAP colocalized with E-cadherin at adherens junctions, and depletion of FilGAP reduced the amount of E-cadherin expressed at the surface. The Rac GAP domain of FilGAP was necessary for the suppression of cell scattering induced by HGF. In agreement with this, siRNA-mediated knockdown of both Rac1 and FilGAP suppressed cell scattering induced by HGF. Forced expression of Rho kinase (ROCK, of which there are two isoforms ROCK1 and ROCK2) induced the accumulation of E-cadherin at the adherens junction, and depletion of FilGAP prevented the accumulation of E-cadherin. Moreover, wild-type FilGAP but not a non-phosphorylatable FilGAP mutant rescued the accumulation of E-cadherin at adherens junctions. These results suggest that FilGAP might regulate cell–cell adhesion through inactivation of Rac downstream of Rho–ROCK-signaling in MDCK cells.
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Affiliation(s)
- Shinichiro Nakahara
- Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Kanagawa 252-0373, Japan
| | - Koji Tsutsumi
- Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Kanagawa 252-0373, Japan
| | - Takuya Zuinen
- Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Kanagawa 252-0373, Japan
| | - Yasutaka Ohta
- Division of Cell Biology, Department of Biosciences, School of Science, Kitasato University, Kanagawa 252-0373, Japan
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17
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Xu X, Xu L, Gao F, Wang J, Ye J, Zhou M, Zhu Y, Tao L. Identification of a novel gene fusion (BMX-ARHGAP) in gastric cardia adenocarcinoma. Diagn Pathol 2014; 9:218. [PMID: 25499959 PMCID: PMC4282731 DOI: 10.1186/s13000-014-0218-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 10/27/2014] [Indexed: 12/31/2022] Open
Abstract
Background Gastric cardia adenocarcinoma (GCA) is one of the major causes of cancer related mortality worldwide. We aim to provide new understanding in the pathogenesis of GCA through investigations on gene expression alterations. Methods We preformed RNA-Seq for one pair of GCA and matched non-tumor tissues. Differentially expressed genes (DEGs) and fusion genes were acquired. PCR and gel analysis in additional 14 pairs of samples were performed to validate the chimeric transcripts. Results 1590 up-regulated and 709 down-regulated genes were detected. Functional analysis revealed that these DEGs were significantly overrepresented in gene ontology items of cell cycle, tumor invasion and proliferation. Moreover, we firstly discovered 3 fusion genes in GCA, including BMX-ARHGAP, LRP5- LITAF and CBX3-C15orf57. The chimeric transcript BMX-ARHGAP was validated and recurrently occurred in 4/15 independent tumor tissues. Conclusions Our results may provide new understanding of GCA and biomarkers for further therapeutic studies. Virtual Slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_218
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Affiliation(s)
- Xiaofeng Xu
- Clinical Laboratory, People's hospital, Jingjiang, 214500, Jiangsu, China.
| | - Lifang Xu
- Department of Gastroenterology, People's hospital, Jingjiang, 214500, Jiangsu, China.
| | - Feng Gao
- Department of General Surgery, People's hospital, Jingjiang, 214500, Jiangsu, China.
| | - Jianjiang Wang
- Department of General Surgery, People's hospital, Jingjiang, 214500, Jiangsu, China.
| | - Jinsong Ye
- Clinical Laboratory, People's hospital, Jingjiang, 214500, Jiangsu, China.
| | - Mingxian Zhou
- Clinical Laboratory, People's hospital, Jingjiang, 214500, Jiangsu, China.
| | - Yunling Zhu
- Clinical Laboratory, People's hospital, Jingjiang, 214500, Jiangsu, China.
| | - Lan Tao
- Clinical Laboratory, People's hospital, Jingjiang, 214500, Jiangsu, China.
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18
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Yun JS, Kim SY. Antihistamines modulate the integrin signaling pathway in h9c2 rat cardiomyocytes: Possible association with cardiotoxicity. Hum Exp Toxicol 2014; 34:796-807. [PMID: 25425550 DOI: 10.1177/0960327114559988] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The identification of biomarkers for toxicity prediction is crucial for drug development and safety evaluation. The selective and specific biomarkers for antihistamines-induced cardiotoxicity is not well identified yet. In order to evaluate the mechanism of the life-threatening effects caused by antihistamines, we used DNA microarrays to analyze genomic profiles in H9C2 rat cardiomyocytes that were treated with antihistamines. The gene expression profiles from drug-treated cells revealed changes in the integrin signaling pathway, suggesting that cardiac arrhythmias induced by antihistamine treatment may be mediated by changes in integrin-mediated signaling. It has been reported that integrin plays a role in QT prolongation that may induce cardiac arrhythmia. These results indicate that the integrin-mediated signaling pathway induced by antihistamines is involved in various biological mechanisms that lead to cardiac QT prolongation. Therefore, we suggest that genomic profiling of antihistamine-treated cardiomyocytes has the potential to reveal the mechanism of adverse drug reactions, and this signal pathway is applicable to prediction of in vitro cardiotoxicity induced by antihistamines as a biomarker candidate.
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Affiliation(s)
- J S Yun
- National Institute of Drug and Safety Evaluation, Ministry of Food and Drug Safety, Osong-eup, Chungcheongbuk-do, Republic of Korea
| | - S Y Kim
- National Institute of Drug and Safety Evaluation, Ministry of Food and Drug Safety, Osong-eup, Chungcheongbuk-do, Republic of Korea
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19
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Darido C, Jane SM. Grhl3 and GEF19 in the front rho. Small GTPases 2014; 1:104-107. [PMID: 21686262 DOI: 10.4161/sgtp.1.2.13620] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 09/10/2010] [Accepted: 09/14/2010] [Indexed: 11/19/2022] Open
Abstract
Directional migration is a critical component of cell motility is observed in many diverse processes including embryogenesis, immune surveillance and wound repair. A central aspect of directional migration is cellular polarity, which is established through several signaling pathways that converge on the small GTPases. These factors orchestrate precise spatial and temporal organization of the actin cytoskeleton at the leading edge of the cell, and induce polarized capture and stabilization of microtubules and their associated microtubule organizing center (MTOC). Studies of the regulation of the GTPases have predominantly focused on post-translational mechanisms involving guanine nucleotide exchange factors (GEFs), GTPase activating proteins (GAPs), and guanine nucleotide dissociation inhibitors (GDIs). In this commentary, we examine the transcriptional regulation of these factors, focusing on the recently described regulation of RhoGEF19, an activator of RhoA, by the epidermal-specific transcription factor GRHL3, and the importance of this regulatory mechanism in wound repair. Our findings establish novel links between epidermal cell migration in wound healing and the planar cell polarity (PCP) signaling pathway, and establish a paradigm for tissue-specific regulation of Rho GTPase activity.
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Affiliation(s)
- Charbel Darido
- Rotary Bone Marrow Research Laboratories; Parkville, Victoria Australia
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20
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Rudnicki A, Isakov O, Ushakov K, Shivatzki S, Weiss I, Friedman LM, Shomron N, Avraham KB. Next-generation sequencing of small RNAs from inner ear sensory epithelium identifies microRNAs and defines regulatory pathways. BMC Genomics 2014; 15:484. [PMID: 24942165 PMCID: PMC4073505 DOI: 10.1186/1471-2164-15-484] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 06/13/2014] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND The mammalian inner ear contains sensory organs, the organ of Corti in the cochlea and cristae and maculae in the vestibule, with each comprised of patterned sensory epithelia that are responsible for hearing and balance. The development, cell fate, patterning, and innervation of both the sensory and nonsensory regions of the inner ear are governed by tight regulation involving, among others, transcription factors and microRNAs (miRNAs). In humans, mutations in specific miRNA genes are associated with hearing loss. In mice, experimental reduction or mutations of miRNAs in the inner ear leads to severe developmental and structural abnormalities. A comprehensive identification of miRNAs in the sensory epithelia and their gene targets will enable pathways of auditory and vestibular function to be defined. RESULTS In this study, we used Next-Generation Sequencing (NGS) to identify the most prominent miRNAs in the inner ear and to define miRNA-target pairs that form pathways crucial for the function of the sensory epithelial cells. NGS of RNA from inner ear sensory epithelial cells led to the identification of 455 miRNAs in both cochlear and vestibular sensory epithelium, with 30 and 44 miRNAs found in only cochlea or vestibule, respectively. miR-6715-3p and miR-6715-5p were defined for the first time in the inner ear. Gene targets were identified for each of these miRNAs, including Arhgap12, a GTPase activating protein, for miR-6715-3p, implicating this miRNA in sensory hair cell bundle development, actin reorganization, cell adhesion and inner ear morphogenesis. CONCLUSIONS This study provides a comprehensive atlas of miRNAs in the inner ear sensory epithelia. The results provide further support of the essential regulatory role of miRNAs in inner ear sensory epithelia and in regulating pathways that define development and growth of these cells.
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Affiliation(s)
| | | | | | | | | | | | | | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
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McCormack J, Welsh NJ, Braga VMM. Cycling around cell-cell adhesion with Rho GTPase regulators. J Cell Sci 2014; 126:379-91. [PMID: 23547086 DOI: 10.1242/jcs.097923] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The formation and stability of epithelial adhesive systems, such as adherens junctions, desmosomes and tight junctions, rely on a number of cellular processes that ensure a dynamic interaction with the cortical cytoskeleton, and appropriate delivery and turnover of receptors at the surface. Unique signalling pathways must be coordinated to allow the coexistence of distinct adhesive systems at discrete sub-domains along junctions and the specific properties they confer to epithelial cells. Rho, Rac and Cdc42 are members of the Rho small GTPase family, and are well-known regulators of cell-cell adhesion. The spatio-temporal control of small GTPase activation drives specific intracellular processes to enable the hierarchical assembly, morphology and maturation of cell-cell contacts. Here, we discuss the small GTPase regulators that control the precise amplitude and duration of the levels of active Rho at cell-cell contacts, and the mechanisms that tailor the output of Rho signalling to a particular cellular event. Interestingly, the functional interaction is reciprocal; Rho regulators drive the maturation of cell-cell contacts, whereas junctions can also modulate the localisation and activity of Rho regulators to operate in diverse processes in the epithelial differentiation programme.
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Affiliation(s)
- Jessica McCormack
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London. Sir Alexander Fleming Building, London SW7 2AZ, UK
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22
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miR-199a-5p regulates urothelial permeability and may play a role in bladder pain syndrome. THE AMERICAN JOURNAL OF PATHOLOGY 2012. [PMID: 23201090 DOI: 10.1016/j.ajpath.2012.10.020] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Defects in urothelial integrity resulting in leakage and activation of underlying sensory nerves are potential causative factors of bladder pain syndrome, a clinical syndrome of pelvic pain and urinary urgency/frequency in the absence of a specific cause. Herein, we identified the microRNA miR-199a-5p as an important regulator of intercellular junctions. On overexpression in urothelial cells, it impairs correct tight junction formation and leads to increased permeability. miR-199a-5p directly targets mRNAs encoding LIN7C, ARHGAP12, PALS1, RND1, and PVRL1 and attenuates their expression levels to a similar extent. Using laser microdissection, we showed that miR-199a-5p is predominantly expressed in bladder smooth muscle but that it is also detected in mature bladder urothelium and primary urothelial cultures. In the urothelium, its expression can be up-regulated after activation of cAMP signaling pathways. While validating miR-199a-5p targets, we delineated novel functions of LIN7C and ARHGAP12 in urothelial integrity and confirmed the essential role of PALS1 in establishing and maintaining urothelial polarity and junction assembly. The present results point to a possible link between miR-199a-5p expression and the control of urothelial permeability in bladder pain syndrome. Up-regulation of miR-199a-5p and concomitant down-regulation of its multiple targets might be detrimental to the establishment of a tight urothelial barrier, leading to chronic pain.
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23
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Understanding molecular mechanisms in peritoneal dissemination of colorectal cancer. Virchows Arch 2012; 461:231-43. [DOI: 10.1007/s00428-012-1287-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 07/05/2012] [Accepted: 07/06/2012] [Indexed: 02/07/2023]
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Chiu TT, Jensen TE, Sylow L, Richter EA, Klip A. Rac1 signalling towards GLUT4/glucose uptake in skeletal muscle. Cell Signal 2011; 23:1546-54. [DOI: 10.1016/j.cellsig.2011.05.022] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Accepted: 05/31/2011] [Indexed: 12/27/2022]
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25
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Howe EN, Cochrane DR, Richer JK. Targets of miR-200c mediate suppression of cell motility and anoikis resistance. Breast Cancer Res 2011; 13:R45. [PMID: 21501518 PMCID: PMC3219208 DOI: 10.1186/bcr2867] [Citation(s) in RCA: 191] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 03/07/2011] [Accepted: 04/18/2011] [Indexed: 02/06/2023] Open
Abstract
INTRODUCTION miR-200c and other members of the miR-200 family promote epithelial identity by directly targeting ZEB1 and ZEB2, which repress E-cadherin and other genes involved in polarity. Loss of miR-200c is often observed in carcinoma cells that have undergone epithelial to mesenchymal transition (EMT). Restoration of miR-200c to such cells leads to a reduction in stem cell-like characteristics, reduced migration and invasion, and increased sensitivity to taxanes. Here we investigate the functional role of novel targets of miR-200c in the aggressive behavior of breast and endometrial cancer cells. METHODS Putative target genes of miR-200c identified by microarray profiling were validated as direct targets using dual luciferase reporter assays. Following restoration of miR-200c to triple negative breast cancer and type 2 endometrial cancer cell lines that had undergone EMT, levels of endogenous target mRNA and respective protein products were measured. Migration and sensitivity to anoikis were determined using wound healing assays or cell-death ELISAs and viability assays respectively. RESULTS We found that restoration of miR-200c suppresses anoikis resistance, a novel function for this influential miRNA. We identified novel targets of miR-200c, including genes encoding fibronectin 1 (FN1), moesin (MSN), neurotrophic tyrosine receptor kinase type 2 (NTRK2 or TrkB), leptin receptor (LEPR), and Rho GTPase activating protein 19 (ARHGAP19). These targets all encode proteins normally expressed in cells of mesenchymal or neuronal origin; however, in carcinoma cells that lack miR-200c they become aberrantly expressed and contribute to the EMT phenotype and aggressive behavior. We showed that these targets are inhibited upon restoration of miR-200c to aggressive breast and endometrial cancer cells. We demonstrated that inhibition of MSN and/or FN1 is sufficient to mediate the ability of miR-200c to suppress cell migration. Lastly, we showed that targeting of TrkB mediates the ability of miR-200c to restore anoikis sensitivity. CONCLUSIONS miR-200c maintains the epithelial phenotype not only by targeting ZEB1/2, which usually facilitates restoration of E-cadherin expression, but also by actively repressing a program of mesenchymal and neuronal genes involved in cell motility and anoikis resistance.
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Affiliation(s)
- Erin N Howe
- Program in Cancer Biology, Department of Pathology, University of Colorado, Anschutz Medical Campus, Mail Stop 8104, PO Box 6511, Aurora, CO, USA
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26
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Dovas A, Choi Y, Yoneda A, Multhaupt HAB, Kwon SH, Kang D, Oh ES, Couchman JR. Serine 34 phosphorylation of rho guanine dissociation inhibitor (RhoGDIalpha) links signaling from conventional protein kinase C to RhoGTPase in cell adhesion. J Biol Chem 2010; 285:23296-308. [PMID: 20472934 PMCID: PMC2906322 DOI: 10.1074/jbc.m109.098129] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Conventional protein kinase C (PKC) isoforms are essential serine/threonine kinases regulating many signaling networks. At cell adhesion sites, PKCα can impact the actin cytoskeleton through its influence on RhoGTPases, but the intermediate steps are not well known. One important regulator of RhoGTPase function is the multifunctional guanine nucleotide dissociation inhibitor RhoGDIα that sequesters several related RhoGTPases in an inactive form, but it may also target them through interactions with actin-associated proteins. Here, it is demonstrated that conventional PKC phosphorylates RhoGDIα on serine 34, resulting in a specific decrease in affinity for RhoA but not Rac1 or Cdc42. The mechanism of RhoGDIα phosphorylation is distinct, requiring the kinase and phosphatidylinositol 4,5-bisphosphate, consistent with recent evidence that the inositide can activate, localize, and orient PKCα in membranes. Phosphospecific antibodies reveal endogenous phosphorylation in several cell types that is sensitive to adhesion events triggered, for example, by hepatocyte growth factor. Phosphorylation is also sensitive to PKC inhibition. Together with fluorescence resonance energy transfer microscopy sensing GTP-RhoA levels, the data reveal a common pathway in cell adhesion linking two essential mediators, conventional PKC and RhoA.
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Affiliation(s)
- Athanassios Dovas
- Division of Biomedical Sciences, Faculty of Medicine, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom
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Ironi L, Panzeri L. A computational framework for qualitative simulation of nonlinear dynamical models of gene-regulatory networks. BMC Bioinformatics 2009; 10 Suppl 12:S14. [PMID: 19828074 PMCID: PMC2762063 DOI: 10.1186/1471-2105-10-s12-s14] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Background Due to the huge amount of information at genomic level made recently available by high-throughput experimental technologies, networks of regulatory interactions between genes and gene products, the so-called gene-regulatory networks, can be uncovered. Most networks of interest are quite intricate because of both the high dimension of interacting elements and the complexity of the kinds of interactions between them. Then, mathematical and computational modeling frameworks are a must to predict the network behavior in response to environmental stimuli. A specific class of Ordinary Differential Equations (ODE) has shown to be adequate to describe the essential features of the dynamics of gene-regulatory networks. But, deriving quantitative predictions of the network dynamics through the numerical simulation of such models is mostly impracticable as they are currently characterized by incomplete knowledge of biochemical reactions underlying regulatory interactions, and of numeric values of kinetic parameters. Results This paper presents a computational framework for qualitative simulation of a class of ODE models, based on the assumption that gene regulation is threshold-dependent, i.e. only effective above or below a certain threshold. The simulation algorithm we propose assumes that threshold-dependent regulation mechanisms are modeled by continuous steep sigmoid functions, unlike other simulation tools that considerably simplifies the problem by approximating threshold-regulated response functions by step functions discontinuous in the thresholds. The algorithm results from the interplay between methods to deal with incomplete knowledge and to study phenomena that occur at different time-scales. Conclusion The work herein presented establishes the computational groundwork for a sound and a complete algorithm capable to capture the dynamical properties that depend only on the network structure and are invariant for ranges of values of kinetic parameters. At the current state of knowledge, the exploitation of such a tool is rather appropriate and useful to understand how specific activity patterns derive from given network structures, and what different types of dynamical behaviors are possible.
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Affiliation(s)
- Liliana Ironi
- IMATI-Consiglio Nazionale delle Ricerche, via Ferrata 1, Pavia, Italy.
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Grise F, Bidaud A, Moreau V. Rho GTPases in hepatocellular carcinoma. Biochim Biophys Acta Rev Cancer 2009; 1795:137-51. [PMID: 19162129 DOI: 10.1016/j.bbcan.2008.12.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Revised: 12/21/2008] [Accepted: 12/24/2008] [Indexed: 01/05/2023]
Abstract
Rho GTPases are major regulators of signal transduction pathways and play key roles in processes including actin dynamics, cell cycle progression, cell survival and gene expression, whose deregulation may lead to tumorigenesis. A growing number of in vitro and in vivo studies using tumor-derived cell lines, primary tumors and animal cancer models strongly suggest that altered Rho GTPase signaling plays an important role in the initiation as well as in the progression of hepatocellular carcinoma (HCC), one of the deadliest human cancers in the world. These alterations can occur at the level of the GTPases themselves or of one of their regulators or effectors. The participation into the tumorigenic process can occur either through the over-expression of one of these components which presents an oncogenic activity as illustrated with RhoA and C or through the attenuation of the expression of a component presenting tumor suppressor activity as for Cdc42 or the RhoGAP, DLC-1. Consequently, these observations reflect the heterogeneity and the complexity of liver carcinogenesis. Recently, pharmacological approaches targeting Rho GTPase signaling have been used in HCC-derived models with relative success but remain to be validated in more physiologically relevant systems. Therefore, therapeutic approaches targeting Rho GTPase signaling may provide a novel alternative for anti-HCC therapy.
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Affiliation(s)
- Florence Grise
- INSERM, U889, Bordeaux, 33076 Bordeaux, France; Université Victor Segalen Bordeaux 2, Bordeaux, 33076 Bordeaux, France
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