1
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A current overview of RhoA, RhoB, and RhoC functions in vascular biology and pathology. Biochem Pharmacol 2022; 206:115321. [DOI: 10.1016/j.bcp.2022.115321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/17/2022] [Accepted: 10/18/2022] [Indexed: 11/24/2022]
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2
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Sharp AK, Newman D, Libonate G, Borns-Stern M, Bevan DR, Brown AM, Anandakrishnan R. Biophysical insights into OR2T7: Investigation of a potential prognostic marker for glioblastoma. Biophys J 2022; 121:3706-3718. [PMID: 35538663 PMCID: PMC9617130 DOI: 10.1016/j.bpj.2022.05.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 04/18/2022] [Accepted: 05/05/2022] [Indexed: 11/21/2022] Open
Abstract
Glioblastoma multiforme (GBM) is the most aggressive and prevalent form of brain cancer, with an expected survival of 12-15 months following diagnosis. GBM affects the glial cells of the central nervous system, which impairs regular brain function including memory, hearing, and vision. GBM has virtually no long-term survival even with treatment, requiring novel strategies to understand disease progression. Here, we identified a somatic mutation in OR2T7, a G-protein-coupled receptor (GPCR), that correlates with reduced progression-free survival for glioblastoma (log rank p-value = 0.05), suggesting a possible role in tumor progression. The mutation, D125V, occurred in 10% of 396 glioblastoma samples in The Cancer Genome Atlas, but not in any of the 2504 DNA sequences in the 1000 Genomes Project, suggesting that the mutation may have a deleterious functional effect. In addition, transcriptome analysis showed that the p38α mitogen-activated protein kinase (MAPK), c-Fos, c-Jun, and JunB proto-oncogenes, and putative tumor suppressors RhoB and caspase-14 were underexpressed in glioblastoma samples with the D125V mutation (false discovery rate < 0.05). Molecular modeling and molecular dynamics simulations have provided preliminary structural insight and indicate a dynamic helical movement network that is influenced by the membrane-embedded, cytofacial-facing residue 125, demonstrating a possible obstruction of G-protein binding on the cytofacial exposed region. We show that the mutation impacts the "open" GPCR conformation, potentially affecting Gα-subunit binding and associated downstream activity. Overall, our findings suggest that the Val125 mutation in OR2T7 could affect glioblastoma progression by downregulating GPCR-p38 MAPK tumor-suppression pathways and impacting the biophysical characteristics of the structure that facilitates Gα-subunit binding. This study provides the theoretical basis for further experimental investigation required to confirm that the D125V mutation in OR2T7 is not a passenger mutation. With validation, the aforementioned mutation could represent an important prognostic marker and a potential therapeutic target for glioblastoma.
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Affiliation(s)
- Amanda K Sharp
- Interdisciplinary Program of Genetics, Bioinformatics, and Computational Biology (GBCB), Virginia Tech, Blacksburg, Virginia
| | - David Newman
- Biomedical Sciences, Edward Via College of Osteopathic Medicine (VCOM), Blacksburg, Virginia
| | - Gianna Libonate
- Biomedical Sciences, Edward Via College of Osteopathic Medicine (VCOM), Blacksburg, Virginia
| | - Mary Borns-Stern
- Biomedical Sciences, Edward Via College of Osteopathic Medicine (VCOM), Blacksburg, Virginia
| | - David R Bevan
- Interdisciplinary Program of Genetics, Bioinformatics, and Computational Biology (GBCB), Virginia Tech, Blacksburg, Virginia; Department of Biochemistry, Virginia Tech, Blacksburg, Virginia
| | - Anne M Brown
- Interdisciplinary Program of Genetics, Bioinformatics, and Computational Biology (GBCB), Virginia Tech, Blacksburg, Virginia; Department of Biochemistry, Virginia Tech, Blacksburg, Virginia; Research and Informatics, University Libraries, Virginia Tech, Blacksburg, Virginia.
| | - Ramu Anandakrishnan
- Biomedical Sciences, Edward Via College of Osteopathic Medicine (VCOM), Blacksburg, Virginia; Biomedical Science and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia; Gibbs Cancer Center and Research Institute, Spartanburg, South Carolina.
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3
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He CQ, Mao L, Yao J, Zhao WC, Huang B, Hu N, Long DX. The Threshold Effects of Low-Dose-Rate Radiation on miRNA-Mediated Neurodevelopment of Zebrafish. Radiat Res 2021; 196:633-646. [PMID: 34399425 DOI: 10.1667/rade-20-00265.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 07/29/2021] [Indexed: 11/03/2022]
Abstract
The biological effects and regulatory mechanisms of low-dose and low-dose-rate radiation are still rather controversial. Therefore, in this study we investigated the effects of low-dose-rate radiation on zebrafish neurodevelopment and the role of miRNAs in radiation-induced neurodevelopment. Zebrafish embryos received prolonged gamma-ray irradiation (0 mGy/h, 0.1 mGy/h, 0.2 mGy/h, 0.4 mGy/h) during development. Neurodevelopmental indicators included mortality, malformation rate, swimming speed, as well as the morphology changes of the lateral line system and brain tissue. Additionally, spatiotemporal expression of development-related miRNAs (dre-miR-196a-5p, dre-miR-210-3p, dre-miR-338) and miRNA processing enzymes genes (Dicer and Drosha) were assessed by qRT-PCR and whole mount in situ hybridization (WISH). The results revealed a decline in mortality, malformation and swimming speed, with normal histological and morphological appearance, in zebrafish that received 0.1 mGy/h; however, increased mortality, malformation and swimming speed were observed, with pathological changes, in zebrafish that received 0.2 mGy/h and 0.4 mGy/h. The expression of miRNA processing enzyme genes was altered after irradiation, and miRNAs expression was downregulated in the 0.1 mGy/h group, and upregulated in the 0.2 mGy/h and 0.4 mGy/h groups. Furthermore, ectopic expression of dre-miR-210-3p, Dicer and Drosha was also observed in the 0.4 mGy/h group. In conclusion, the effect of low-dose and low-dose-rate radiation on neurodevelopment follows the threshold model, under the regulation of miRNAs, excitatory effects occurred at a dose rate of 0.1 mGy/h and toxic effects occurred at a dose rate of 0.2 mGy/h and 0.4 mGy/h.
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Affiliation(s)
- Chu-Qi He
- School of Public Health, University of South China, Hengyang 421001, PR China.,Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, Hengyang, Hunan 421001, China
| | - Liang Mao
- School of Public Health, University of South China, Hengyang 421001, PR China.,Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, Hengyang, Hunan 421001, China
| | - Jin Yao
- School of Public Health, University of South China, Hengyang 421001, PR China.,Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, Hengyang, Hunan 421001, China
| | - Wei-Chao Zhao
- School of Public Health, University of South China, Hengyang 421001, PR China.,Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, Hengyang, Hunan 421001, China
| | - Bo Huang
- School of Public Health, University of South China, Hengyang 421001, PR China.,Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, Hengyang, Hunan 421001, China
| | - Nan Hu
- Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Hengyang, Hunan 421001, China
| | - Ding-Xin Long
- School of Public Health, University of South China, Hengyang 421001, PR China.,Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, Hengyang, Hunan 421001, China
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4
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Cheng C, Seen D, Zheng C, Zeng R, Li E. Role of Small GTPase RhoA in DNA Damage Response. Biomolecules 2021; 11:212. [PMID: 33546351 PMCID: PMC7913530 DOI: 10.3390/biom11020212] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 01/28/2021] [Accepted: 01/31/2021] [Indexed: 02/06/2023] Open
Abstract
Accumulating evidence has suggested a role of the small GTPase Ras homolog gene family member A (RhoA) in DNA damage response (DDR) in addition to its traditional function of regulating cell morphology. In DDR, 2 key components of DNA repair, ataxia telangiectasia-mutated (ATM) and flap structure-specific endonuclease 1 (FEN1), along with intracellular reactive oxygen species (ROS) have been shown to regulate RhoA activation. In addition, Rho-specific guanine exchange factors (GEFs), neuroepithelial transforming gene 1 (Net1) and epithelial cell transforming sequence 2 (Ect2), have specific functions in DDR, and they also participate in Ras-related C3 botulinum toxin substrate 1 (Rac1)/RhoA interaction, a process which is largely unappreciated yet possibly of significance in DDR. Downstream of RhoA, current evidence has highlighted its role in mediating cell cycle arrest, which is an important step in DNA repair. Unraveling the mechanism by which RhoA modulates DDR may provide more insight into DDR itself and may aid in the future development of cancer therapies.
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Affiliation(s)
| | | | | | | | - Enmin Li
- Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou 515031, Guangdong, China; (C.C.); (D.S.); (C.Z.); (R.Z.)
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5
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Bernardini A, Lorenzo M, Nardini M, Mantovani R, Gnesutta N. The phosphorylatable Ser320 of NF-YA is involved in DNA binding of the NF-Y trimer. FASEB J 2018; 33:4790-4801. [PMID: 30589568 DOI: 10.1096/fj.201801989r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Nuclear factor Y (NF-Y) is a transcription factor trimer binding to the functionally important CCAAT box, present in promoters of growth-promoting and cell cycle-regulated genes. The regulatory nuclear factor YA (NF-YA) subunit confers sequence-specificity to the histone-like nuclear factor YB/YC dimer. NF-YA harbors 2 serines-Ser320 and Ser326-shown to be phosphorylated by cyclin-dependent kinase 2. High-throughput proteomics data indicate that they are phosphorylated in vivo. Specifically, Ser320 makes structural contacts with the DNA phosphate backbone; Ser320-P is the major NF-YA phosphorylation isoform following overexpression in HeLa cells, increasing upon mitotic arrest. EMSA with recombinant Ala and Glu mutants confirm a role of Ser320, but not Ser326, in stabilization of DNA binding. Transactivation assays of the CCAAT-dependent MDR1 and RHOB promoters show loss in transcription function for Ser320Glu and Ser320Ala NF-YA mutants. Phylogenetic analysis of NF-YA proteins indicates that Ser320 is indeed evolutionarily conserved. We conclude that phosphorylation of this residue belongs to the core mechanisms of DNA-binding control, possibly driven by the necessity to unfasten binding of or to evict NF-Y from CCAAT sites under specific conditions of growth regulation.-Bernardini, A., Lorenzo, M., Nardini, M., Mantovani, R., Gnesutta, N. The phosphorylatable Ser320 of NF-YA is involved in DNA binding of the NF-Y trimer.
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Affiliation(s)
- Andrea Bernardini
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Mariangela Lorenzo
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Marco Nardini
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Roberto Mantovani
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
| | - Nerina Gnesutta
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy
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6
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Nomikou E, Livitsanou M, Stournaras C, Kardassis D. Transcriptional and post-transcriptional regulation of the genes encoding the small GTPases RhoA, RhoB, and RhoC: implications for the pathogenesis of human diseases. Cell Mol Life Sci 2018; 75:2111-2124. [PMID: 29500478 PMCID: PMC11105751 DOI: 10.1007/s00018-018-2787-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 01/25/2018] [Accepted: 02/26/2018] [Indexed: 12/15/2022]
Abstract
Rho GTPases are highly conserved proteins that play critical roles in many cellular processes including actin dynamics, vesicular trafficking, gene transcription, cell-cycle progression, and cell adhesion. The main mode of regulation of Rho GTPases is through guanine nucleotide binding (cycling between an active GTP-bound form and an inactive GDP-bound form), but transcriptional, post-transcriptional, and post-translational modes of Rho regulation have also been described. In the present review, we summarize recent progress on the mechanisms that control the expression of the three members of the Rho-like subfamily (RhoA, RhoB, and RhoC) at the level of gene transcription as well as their post-transcriptional regulation by microRNAs. We also discuss the progress made in deciphering the mechanisms of cross-talk between Rho proteins and the transforming growth factor β signaling pathway and their implications for the pathogenesis of human diseases such as cancer metastasis and fibrosis.
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Affiliation(s)
- Eirini Nomikou
- Laboratory of Biochemistry, Department of Medicine, University of Crete, 71003, Heraklion, Greece
| | - Melina Livitsanou
- Laboratory of Biochemistry, Department of Medicine, University of Crete, 71003, Heraklion, Greece
| | - Christos Stournaras
- Laboratory of Biochemistry, Department of Medicine, University of Crete, 71003, Heraklion, Greece
| | - Dimitris Kardassis
- Laboratory of Biochemistry, Department of Medicine, University of Crete, 71003, Heraklion, Greece.
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 71110, Heraklion, Greece.
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7
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Ovarian tumour growth is characterized by mevalonate pathway gene signature in an orthotopic, syngeneic model of epithelial ovarian cancer. Oncotarget 2018; 7:47343-47365. [PMID: 27329838 PMCID: PMC5216946 DOI: 10.18632/oncotarget.10121] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 06/04/2016] [Indexed: 12/26/2022] Open
Abstract
Epithelial ovarian cancer (EOC) is the most lethal gynecological cancer and often is not detected until late stages when cancer cells transcoelomically metastasize to the abdomen and typically become resistant to therapy resulting in very low survival rates. We utilize an orthotopic, syngeneic mouse model to study late stage disease and have discovered that the tumor cells within the abdominal ascites are irreversibly re-programmed, with an increased tumorigenicity and resistance to apoptosis. The goal of this study was to characterize the reprogramming that occurred in the aggressive ascites-derived cells (28-2 cells) compared to the original cell line used for tumor induction (ID8 cells). Microarray experiments showed that the majority of genes upregulated in the 28-2 cells belonged to the mevalonate pathway, which is involved in cholesterol biosynthesis, protein prenylation, and activation of small GTPases. Upregulation of mevalonate appeared to be associated with the acquisition of a p53 mutation in the ascites-derived cells. Treatment with simvastatin to inhibit HMG CoA reductase, the rate limiting enzyme of this pathway, induced apoptosis in the 28-2 cell line. Rescue experiments revealed that mevalonate, but not cholesterol, could inhibit the simvastatin-mediated effects. In vivo, daily intraperitoneal simvastatin treatment significantly regressed advanced stage disease and induced death of metastatic tumor cells. These data suggest that ovarian cancer cells become reprogrammed, with genetic mutations, and upregulation of the mevalonate pathway, which facilitates the development of advanced stage disease. The use of statins to inhibit HMGCR may provide novel therapeutic opportunities for the treatment of advanced stage EOC.
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8
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Ju JA, Gilkes DM. RhoB: Team Oncogene or Team Tumor Suppressor? Genes (Basel) 2018; 9:E67. [PMID: 29385717 PMCID: PMC5852563 DOI: 10.3390/genes9020067] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 01/21/2018] [Accepted: 01/24/2018] [Indexed: 12/31/2022] Open
Abstract
Although Rho GTPases RhoA, RhoB, and RhoC share more than 85% amino acid sequence identity, they play very distinct roles in tumor progression. RhoA and RhoC have been suggested in many studies to contribute positively to tumor development, but the role of RhoB in cancer remains elusive. RhoB contains a unique C-terminal region that undergoes specific post-translational modifications affecting its localization and function. In contrast to RhoA and RhoC, RhoB not only localizes at the plasma membrane, but also on endosomes, multivesicular bodies and has even been identified in the nucleus. These unique features are what contribute to the diversity and potentially opposing functions of RhoB in the tumor microenvironment. Here, we discuss the dualistic role that RhoB plays as both an oncogene and tumor suppressor in the context of cancer development and progression.
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Affiliation(s)
- Julia A Ju
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA.
| | - Daniele M Gilkes
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA.
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9
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Nomikou E, Stournaras C, Kardassis D. Functional analysis of the promoters of the small GTPases RhoA and RhoB in embryonic stem cells. Biochem Biophys Res Commun 2017; 491:754-759. [PMID: 28739254 DOI: 10.1016/j.bbrc.2017.07.114] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 07/20/2017] [Indexed: 01/01/2023]
Abstract
Small GTPases of the Rho subfamily have been implicated in many physiological and pathological processes in various cell types including embryonic stem cells (ESCs). In the present study we performed a functional analysis of the promoters of the RhoA and the RhoB genes in order to identify regulatory elements that are important for their transcriptional control in ESCs. We show that RhoA mRNA levels were significantly higher compared with the RhoB mRNA levels in ESCs as well in various cancer cell lines and this difference could be accounted for by differences in the activities of the corresponding promoters. Deletion analysis of the RhoA and RhoB promoters in ESCs revealed that the proximal regions contain regulatory elements that are critical for their activity. Both proximal promoters contain CCAAT boxes and mutagenesis of these elements decreased significantly the activity of both promoters suggesting a coordinated regulation of the two genes by CCAAT box binding factors. Finally, we show that both genes are subjects to autoregulation in ESCs and in the case of RhoB, this autoregulation requires the GTPase activity of the Rho proteins. Understanding the mechanisms that control the transcription of Rho GTPases in ESCs may shed new light into the still unknown roles of these proteins in stem cell functions.
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Affiliation(s)
- Eirini Nomikou
- Laboratory of Biochemistry, Division of Basic Medical Sciences, University of Crete Medical School, Heraklion 71003, Greece
| | - Christos Stournaras
- Laboratory of Biochemistry, Division of Basic Medical Sciences, University of Crete Medical School, Heraklion 71003, Greece
| | - Dimitris Kardassis
- Laboratory of Biochemistry, Division of Basic Medical Sciences, University of Crete Medical School, Heraklion 71003, Greece; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion 71003, Greece.
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10
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Watson G, Ronai ZA, Lau E. ATF2, a paradigm of the multifaceted regulation of transcription factors in biology and disease. Pharmacol Res 2017; 119:347-357. [PMID: 28212892 PMCID: PMC5457671 DOI: 10.1016/j.phrs.2017.02.004] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/01/2017] [Accepted: 02/02/2017] [Indexed: 01/16/2023]
Abstract
Stringent transcriptional regulation is crucial for normal cellular biology and organismal development. Perturbations in the proper regulation of transcription factors can result in numerous pathologies, including cancer. Thus, understanding how transcription factors are regulated and how they are dysregulated in disease states is key to the therapeutic targeting of these factors and/or the pathways that they regulate. Activating transcription factor 2 (ATF2) has been studied in a number of developmental and pathological conditions. Recent findings have shed light on the transcriptional, post-transcriptional, and post-translational regulatory mechanisms that influence ATF2 function, and thus, the transcriptional programs coordinated by ATF2. Given our current knowledge of its multiple levels of regulation and function, ATF2 represents a paradigm for the mechanistic complexity that can regulate transcription factor function. Thus, increasing our understanding of the regulation and function of ATF2 will provide insights into fundamental regulatory mechanisms that influence how cells integrate extracellular and intracellular signals into a genomic response through transcription factors. Characterization of ATF2 dysfunction in the context of pathological conditions, particularly in cancer biology and response to therapy, will be important in understanding how pathways controlled by ATF2 or other transcription factors might be therapeutically exploited. In this review, we provide an overview of the currently known upstream regulators and downstream targets of ATF2.
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Affiliation(s)
- Gregory Watson
- Department of Tumor Biology and Program in Chemical Biology and Molecular Medicine, H. Lee Moffitt Cancer Center, Tampa, FL, USA
| | - Ze'ev A Ronai
- Tumor Initiation and Maintenance Program, Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA; Technion Integrated Cancer Center, Rappaport Faculty of Medicine, Technion, Haifa, 3109601, Israel
| | - Eric Lau
- Department of Tumor Biology and Program in Chemical Biology and Molecular Medicine, H. Lee Moffitt Cancer Center, Tampa, FL, USA.
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11
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Diao F, Chen K, Wang Y, Li Y, Xu W, Lu J, Chen YX. Involvement of small G protein RhoB in the regulation of proliferation, adhesion and migration by dexamethasone in osteoblastic cells. PLoS One 2017; 12:e0174273. [PMID: 28323887 PMCID: PMC5360316 DOI: 10.1371/journal.pone.0174273] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/06/2017] [Indexed: 12/02/2022] Open
Abstract
Long-term exposure to therapeutic doses of glucocorticoids (GCs) results in bone remodeling, which frequently causes osteoporosis and fracture healing retardation because of the abnormality of osteoblastic proliferation and differentiation. The mechanisms of GCs’ effect on osteoblasts are largely unknown. In this present study, we found that dexamethasone (Dex) could induce the expression of the small G protein, RhoB, in mRNA and protein levels in the osteoblast-derived osteosarcoma cell lines MG-63. The up-regulation of RhoB mRNA by Dex mainly occurs at posttranscriptional level by increasing its mRNA stability through PI-3K/Akt and p38 mitogen-activated protein kinase signaling pathways. Over-expression of RhoB in MG-63 cells magnified while down-regulation of RhoB level by RNA interference impaired Dex-induced growth inhibition but not differentiation. What’s more, over-expression of RhoB mimicked the effect of Dex on cell adhesion and migration. And interfering RhoB expression partially suppressed Dex-induced pro-adhesion and anti-migration in MG-63 cells. In conclusion, these results indicate that RhoB plays an important role in the pathological effect of Dex on osteoblastic growth and migration, which is a part of the mechanisms of GCs’ adverse effect on bone remodeling.
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Affiliation(s)
- Fei Diao
- Department of Pathophysiology, Second Military Medical University, Shanghai, China
| | - Kangyao Chen
- Department of Orthopedics, Changhai Hospital affiliated to Second Military Medical University, Shanghai, China
- Department of -Orthopedics, Fuzhou Second Hospital affiliated to Xiamen University, Fuzhou, Fujian Province, China
| | - Yan Wang
- Department of Pathophysiology, Second Military Medical University, Shanghai, China
| | - Yidong Li
- Department of Pathophysiology, Second Military Medical University, Shanghai, China
| | - Weidong Xu
- Department of Orthopedics, Changhai Hospital affiliated to Second Military Medical University, Shanghai, China
| | - Jian Lu
- Department of Pathophysiology, Second Military Medical University, Shanghai, China
- * E-mail: (JL); (YXC)
| | - Yu-Xia Chen
- Department of Pathophysiology, Second Military Medical University, Shanghai, China
- * E-mail: (JL); (YXC)
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12
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Delmas A, Cherier J, Pohorecka M, Medale-Giamarchi C, Meyer N, Casanova A, Sordet O, Lamant L, Savina A, Pradines A, Favre G. The c-Jun/RHOB/AKT pathway confers resistance of BRAF-mutant melanoma cells to MAPK inhibitors. Oncotarget 2016; 6:15250-64. [PMID: 26098773 PMCID: PMC4558149 DOI: 10.18632/oncotarget.3888] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 04/25/2015] [Indexed: 11/25/2022] Open
Abstract
The response of BRAF-mutant melanoma patients to BRAF inhibitors is dramatically impaired by secondary resistances and rapid relapse. So far, the molecular mechanisms driving these resistances are not completely understood. Here, we show that, in BRAF-mutant melanoma cells, inhibition of BRAF or its target MEK induces RHOB expression by a mechanism that depends on the transcription factor c-Jun. In those cells, RHOB deficiency causes hypersensitivity to BRAF and MEK inhibitors-induced apoptosis. Supporting these results, loss of RHOB expression in metastatic melanoma tissues is associated with an increased progression-free survival of BRAF-mutant patients treated with vemurafenib. Following BRAF inhibition, RHOB activates AKT whose inhibition causes hypersensitivity of BRAF-mutant melanoma cells to BRAF inhibitors. In mice, AKT inhibition synergizes with vemurafenib to block tumor growth of BRAF-mutant metastatic melanoma. Our findings reveal that BRAF inhibition activates a c-Jun/RHOB/AKT pathway that promotes tumor cell survival and further support a role of this pathway in the resistance of melanoma to vemurafenib. Our data also highlight the importance of using RHOB tumor levels as a biomarker to predict vemurafenib patient's response and to select those that would benefit of the combination with AKT inhibitors.
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Affiliation(s)
- Audrey Delmas
- Inserm, UMR 1037-CRCT, Toulouse, France.,Université Paul Sabatier, Toulouse, France.,Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse-Oncopole, Laboratory of Medical Biology and Oncogenetics, Toulouse, France
| | - Julia Cherier
- Inserm, UMR 1037-CRCT, Toulouse, France.,Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse-Oncopole, Laboratory of Medical Biology and Oncogenetics, Toulouse, France
| | - Magdalena Pohorecka
- Inserm, UMR 1037-CRCT, Toulouse, France.,Université Paul Sabatier, Toulouse, France.,Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse-Oncopole, Laboratory of Medical Biology and Oncogenetics, Toulouse, France
| | - Claire Medale-Giamarchi
- Inserm, UMR 1037-CRCT, Toulouse, France.,Université Paul Sabatier, Toulouse, France.,Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse-Oncopole, Laboratory of Medical Biology and Oncogenetics, Toulouse, France
| | - Nicolas Meyer
- Inserm, UMR 1037-CRCT, Toulouse, France.,Université Paul Sabatier, Toulouse, France.,Centre Hospitalo-Universitaire de Toulouse, Institut Universitaire du Cancer de Toulouse-Oncopole, Department of Dermatology, Toulouse, France
| | - Anne Casanova
- Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse-Oncopole, Laboratory of Medical Biology and Oncogenetics, Toulouse, France
| | - Olivier Sordet
- Inserm, UMR 1037-CRCT, Toulouse, France.,Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse-Oncopole, Laboratory of Medical Biology and Oncogenetics, Toulouse, France
| | - Laurence Lamant
- Inserm, UMR 1037-CRCT, Toulouse, France.,Centre Hospitalo-Universitaire de Toulouse, Institut Universitaire du Cancer de Toulouse-Oncopole, Department of Pathology, Toulouse, France
| | - Ariel Savina
- Scientific Partnerships, Roche SAS, Boulogne Billancourt, France
| | - Anne Pradines
- Inserm, UMR 1037-CRCT, Toulouse, France.,Université Paul Sabatier, Toulouse, France.,Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse-Oncopole, Laboratory of Medical Biology and Oncogenetics, Toulouse, France
| | - Gilles Favre
- Inserm, UMR 1037-CRCT, Toulouse, France.,Université Paul Sabatier, Toulouse, France.,Institut Claudius Regaud, Institut Universitaire du Cancer de Toulouse-Oncopole, Laboratory of Medical Biology and Oncogenetics, Toulouse, France
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13
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Marlow LA, Bok I, Smallridge RC, Copland JA. RhoB upregulation leads to either apoptosis or cytostasis through differential target selection. Endocr Relat Cancer 2015. [PMID: 26206775 PMCID: PMC4559850 DOI: 10.1530/erc-14-0302] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Anaplastic thyroid carcinoma is a highly aggressive undifferentiated carcinoma with a mortality rate near 100% due to an assortment of genomic abnormalities which impede the success of therapeutic options. Our laboratory has previously identified that RhoB upregulation serves as a novel molecular therapeutic target and agents upregulating RhoB combined with paclitaxel lead to antitumor synergy. Knowing that histone deacetylase 1 (HDAC1) transcriptionally suppresses RhoB, we sought to extend our findings to other HDACs and to identify the HDAC inhibitor (HDACi) that optimally synergize with paclitaxel. Here we identify HDAC6 as a newly discovered RhoB repressor. By using isoform selective HDAC inhibitors (HDACi) and shRNAs, we show that RhoB has divergent downstream signaling partners, which are dependent on the HDAC isoform that is inhibited. When RhoB upregulates only p21 (cyclin kinase inhibitor) using a class I HDACi (romidepsin), cells undergo cytostasis. When RhoB upregulates BIMEL using class II/(I) HDACi (belinostat or vorinostat), apoptosis occurs. Combinatorial synergy with paclitaxel is dependent upon RhoB and BIMEL while upregulation of RhoB and only p21 blocks synergy. This bifurcated regulation of the cell cycle by RhoB is novel and silencing either p21 or BIMEL turns the previously silenced pathway on, leading to phenotypic reversal. This study intimates that the combination of belinostat/vorinostat with paclitaxel may prove to be an effective therapeutic strategy via the novel observation that class II/(I) HDACi antagonize HDAC6-mediated suppression of RhoB and subsequent BIMEL, thereby promoting antitumor synergy. These overall observations may provide a mechanistic understanding of optimal therapeutic response.
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Affiliation(s)
- Laura A Marlow
- Departments of Cancer BiologyInternal MedicineDivision of EndocrinologyEndocrine Malignancy Working GroupMayo Clinic, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
| | - Ilah Bok
- Departments of Cancer BiologyInternal MedicineDivision of EndocrinologyEndocrine Malignancy Working GroupMayo Clinic, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
| | - Robert C Smallridge
- Departments of Cancer BiologyInternal MedicineDivision of EndocrinologyEndocrine Malignancy Working GroupMayo Clinic, 4500 San Pablo Road, Jacksonville, Florida 32224, USA Departments of Cancer BiologyInternal MedicineDivision of EndocrinologyEndocrine Malignancy Working GroupMayo Clinic, 4500 San Pablo Road, Jacksonville, Florida 32224, USA Departments of Cancer BiologyInternal MedicineDivision of EndocrinologyEndocrine Malignancy Working GroupMayo Clinic, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
| | - John A Copland
- Departments of Cancer BiologyInternal MedicineDivision of EndocrinologyEndocrine Malignancy Working GroupMayo Clinic, 4500 San Pablo Road, Jacksonville, Florida 32224, USA Departments of Cancer BiologyInternal MedicineDivision of EndocrinologyEndocrine Malignancy Working GroupMayo Clinic, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
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14
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Wang M, Guo L, Wu Q, Zeng T, Lin Q, Qiao Y, Wang Q, Liu M, Zhang X, Ren L, Zhang S, Pei Y, Yin Z, Ding F, Wang HR. ATR/Chk1/Smurf1 pathway determines cell fate after DNA damage by controlling RhoB abundance. Nat Commun 2014; 5:4901. [PMID: 25249323 DOI: 10.1038/ncomms5901] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 08/02/2014] [Indexed: 11/09/2022] Open
Abstract
ATM- and RAD3-related (ATR)/Chk1 and ataxia-telangiectasia mutated (ATM)/Chk2 signalling pathways play critical roles in the DNA damage response. Here we report that the E3 ubiquitin ligase Smurf1 determines cell apoptosis rates downstream of DNA damage-induced ATR/Chk1 signalling by promoting degradation of RhoB, a small GTPase recognized as tumour suppressor by promoting death of transformed cells. We show that Smurf1 targets RhoB for degradation to control its abundance in the basal state. DNA damage caused by ultraviolet light or the alkylating agent methyl methanesulphonate strongly activates Chk1, leading to phosphorylation of Smurf1 that enhances its self-degradation, hence resulting in a RhoB accumulation to promote apoptosis. Suppressing RhoB levels by overexpressing Smurf1 or blocking Chk1-dependent Smurf1 self-degradation significantly inhibits apoptosis. Hence, our study unravels a novel ATR/Chk1/Smurf1/RhoB pathway that determines cell fate after DNA damage, and raises the possibility that aberrant upregulation of Smurf1 promotes tumorigenesis by excessively targeting RhoB for degradation.
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Affiliation(s)
- Meilin Wang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Lei Guo
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Qingang Wu
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Taoling Zeng
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Qi Lin
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Yikai Qiao
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Qun Wang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Mingdong Liu
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Xin Zhang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Lan Ren
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Sheng Zhang
- Department of Surgery, Zhongshan Hospital, Xiamen University, Xiamen, Fujian 361005, China
| | - Yihua Pei
- Central Laboratory, Zhongshan Hospital, Xiamen University, Xiamen, Fujian 361005, China
| | - Zhenyu Yin
- Department of Surgery, Zhongshan Hospital, Xiamen University, Xiamen, Fujian 361005, China
| | - Feng Ding
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Hong-Rui Wang
- 1] State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China [2] Shenzhen Research Institute of Xiamen University, Shenzhen, Guangdong 518057, China
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15
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Kim BK, Im JY, Han G, Lee WJ, Won KJ, Chung KS, Lee K, Ban HS, Song K, Won M. p300 cooperates with c-Jun and PARP-1 at the p300 binding site to activate RhoB transcription in NSC126188-mediated apoptosis. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:364-73. [DOI: 10.1016/j.bbagrm.2014.03.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 03/09/2014] [Accepted: 03/10/2014] [Indexed: 11/27/2022]
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16
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Ahn J, Won M, Choi JH, Kim YS, Jung CR, Im DS, Kyun ML, Lee K, Song KB, Chung KS. Reactive oxygen species-mediated activation of the Akt/ASK1/p38 signaling cascade and p21Cip1 downregulation are required for shikonin-induced apoptosis. Apoptosis 2013; 18:870-81. [DOI: 10.1007/s10495-013-0835-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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17
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Huelsenbeck J, May M, Schulz F, Schelle I, Ronkina N, Hohenegger M, Fritz G, Just I, Gerhard R, Genth H. Cytoprotective effect of the small GTPase RhoB expressed upon treatment of fibroblasts with the Ras-glucosylating Clostridium sordellii lethal toxin. FEBS Lett 2012; 586:3665-73. [PMID: 22982107 DOI: 10.1016/j.febslet.2012.08.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 08/24/2012] [Accepted: 08/24/2012] [Indexed: 01/02/2023]
Abstract
Mono-glucosylation of (H/K/N)Ras by Clostridium sordellii lethal toxin (TcsL) blocks critical survival signaling pathways, resulting in apoptosis. In this study, TcsL and K-Ras knock-down by siRNA are presented to result in expression of the cell death-regulating small GTPase RhoB. TcsL-induced RhoB expression is based on transcriptional activation involving p38(alpha) MAP kinase. Newly synthesized RhoB protein is rapidly degraded in a proteasome- and a caspase-dependent manner, providing first evidence for caspase-dependent degradation of a Rho family protein. Although often characterised as a pro-apoptotic protein, RhoB suppresses caspase-3 activation in TcsL-treated fibroblasts. The finding on the cytoprotective activity of RhoB in TcsL-treated cells re-enforces the concept that RhoB exhibits cytoprotective rather than pro-apoptotic activity in a cellular background of inactive Ras.
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18
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Abstract
Signaling through the Rho family of small GTPases regulates a variety of cellular processes via changes in the actin cytoskeleton. Here we discuss recent findings that show the transcription factor p53 regulates the expression of several Rho pathway signaling molecules, and how mutation of p53 in cancer dramatically alters signaling output through this pathway.
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Affiliation(s)
- Daniel R Croft
- The Beatson Institute for Cancer Research, Garscube Estate; Glasgow, UK
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19
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Lau E, Ronai ZA. ATF2 - at the crossroad of nuclear and cytosolic functions. J Cell Sci 2012; 125:2815-24. [PMID: 22685333 DOI: 10.1242/jcs.095000] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
An increasing number of transcription factors have been shown to elicit oncogenic and tumor suppressor activities, depending on the tissue and cell context. Activating transcription factor 2 (ATF2; also known as cAMP-dependent transcription factor ATF-2) has oncogenic activities in melanoma and tumor suppressor activities in non-malignant skin tumors and breast cancer. Recent work has shown that the opposing functions of ATF2 are associated with its subcellular localization. In the nucleus, ATF2 contributes to global transcription and the DNA damage response, in addition to specific transcriptional activities that are related to cell development, proliferation and death. ATF2 can also translocate to the cytosol, primarily following exposure to severe genotoxic stress, where it impairs mitochondrial membrane potential and promotes mitochondrial-based cell death. Notably, phosphorylation of ATF2 by the epsilon isoform of protein kinase C (PKCε) is the master switch that controls its subcellular localization and function. Here, we summarize our current understanding of the regulation and function of ATF2 in both subcellular compartments. This mechanism of control of a non-genetically modified transcription factor represents a novel paradigm for 'oncogene addiction'.
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Affiliation(s)
- Eric Lau
- Signal Transduction Program, Sanford-Burnham Medical Research Institute, 10901 N. Torrey Pines Rd, La Jolla, CA 92130, USA.
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