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Majumder M, Janakiraman H, Chakraborty P, Vijayakumar A, Mayhue S, Yu H, Dincman T, Martin R, O’Quinn E, Mehrotra S, Palanisamy V. RNA-binding protein HuR reprograms immune T cells and promotes oral squamous cell carcinoma. ORAL ONCOLOGY REPORTS 2024; 10:100296. [PMID: 38681116 PMCID: PMC11044901 DOI: 10.1016/j.oor.2024.100296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
Hu Antigen R, also known as ELAVL1 (HuR), is a key posttranscriptional regulator in eukaryotic cells. HuR overexpression promotes several malignancies, including head and neck squamous cell carcinoma (HNSCC). However, its immune dysfunction-associated tumorigenesis pathways remain unknown. We examined HuR's effects on oral malignancies and immune cell function in vitro and in vivo using oral carcinoma cells and transgenic HuR knockout (KO) mice. CRISPR/Cas9-mediated HuR deletion in mice syngeneic oral cancer cells eliminated colony formation and tumor development. HuR-KO tumors had a lower tumor volume, fewer CD4+CD25+FoxP3+ regulatory T cells, and more CD8+ T cells, suggesting that HuR may suppress the immune response during oral cancer progression. In contrast, HuR KO oral epithelial tissues are resistant to 4NQO-induced oral malignancies compared to control tumor-bearing mice. HuR KO mice showed fewer Tregs and greater IFN levels than WT tumor-bearing mice, suggesting anticancer activity. Finally, the HuR inhibitor pyrvinium pamoate lowers tumor burden by enhancing CD8+ infiltration at the expense of CD4+, suggesting anticancer benefits. Thus, HuR-dependent oral neoplasia relies on immunological dysfunction, suggesting that decreasing HuR may boost antitumor potential and offer a novel HNSCC therapy.
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Affiliation(s)
| | | | | | | | - Sari Mayhue
- Department of Biochemistry and Molecular Biology, USA
| | - Hong Yu
- Oral Health Sciences, College of Dental Medicine, USA
| | - Toros Dincman
- Department of Haematology and Oncology, College of Medicine, USA
| | - Romeo Martin
- Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Elizabeth O’Quinn
- Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, 29425, USA
| | | | - Viswanathan Palanisamy
- Department of Biochemistry and Molecular Biology, USA
- Division of Molecular Medicine, Department of Internal Medicine, UNM Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM, 87131, USA
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Kakuguchi W, Kitamura T, Takahashi T, Yanagawa-Matsuda A, Fang CY, Ohiro Y, Higashino F. Human antigen R knockdown attenuates the invasive activity of oral cancer cells through inactivation of matrix metalloproteinase-1 gene expression. J Dent Sci 2024; 19:154-161. [PMID: 38303892 PMCID: PMC10829560 DOI: 10.1016/j.jds.2023.05.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 05/11/2023] [Indexed: 02/03/2024] Open
Abstract
Background/purpose The RNA-binding protein human antigen R (HuR) recognizes AU-rich elements in the 3'-untranslated regions of mRNA. The expression of cytoplasmic HuR is related to the malignancy of many carcinomas. The aim of this study is investigation of effect of HuR knockdown for invasive activity of oral carcinoma. Materials and methods Proliferation, invasion, real-time PCR, and reporter gene assays were performed to confirm that the knockdown of HuR downregulates the invasive activity of cancer cells. Immunohistochemical staining was performed for high invasive carcinoma, squamous cell carcinoma (SCC) and low invasive carcinoma, verrucous carcinoma (VC), to determine if the localization of cytoplasmic HuR is related to matrix metalloproteinase-1 (MMP-1) expression. Results Invasive activity was significantly lower in HuR knockdown cancer cells than in control cells. A luciferase assay revealed that HuR knockdown inactivated the promoter activity of the MMP-1 gene. The mRNA levels of the transcription factors required for MMP-1 expression, including c-fos and c-jun, were decreased in HuR knockdown cancer cells. Immunohistochemical analysis revealed the level of cytoplasmic HuR and MMP-1 in invasive carcinoma to be higher than in low invasive cancer. HuR induced MMP-1 expression in the invasive front of most SCC cases. Conclusion HuR knockdown attenuated the invasive activity of cancer cells by decreasing the expression of the MMP-1, at least partially. HuR localization may help determine the invasive phenotype of cancer cells and inhibit cancer cell invasion. Furthermore, in oral SCC, HuR may be related to invasive activity through the expression of MMP-1.
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Affiliation(s)
- Wataru Kakuguchi
- Department of Vascular Biology and Molecular Pathology, Division of Oral Pathobiological Science, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
- Department of Oral and Maxillofacial Surgery, Division of Oral Pathobiological Science, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Tetsuya Kitamura
- Department of Vascular Biology and Molecular Pathology, Division of Oral Pathobiological Science, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
- Hokkaido Oral Pathology Diagnostic Clinic, Sapporo, Japan
| | - Tomomi Takahashi
- Support Section for Education and Research, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Aya Yanagawa-Matsuda
- Department of Vascular Biology and Molecular Pathology, Division of Oral Pathobiological Science, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Chih-Yuan Fang
- Department of Oral and Maxillofacial Surgery, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
- School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yoichi Ohiro
- Department of Oral and Maxillofacial Surgery, Division of Oral Pathobiological Science, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Fumihiro Higashino
- Department of Vascular Biology and Molecular Pathology, Division of Oral Pathobiological Science, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
- Department of Molecular Oncology, Faculty of Dental Medicine and Graduate School of Biomedical Science and Engineering, Hokkaido University, Sapporo, Japan
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Assoni G, La Pietra V, Digilio R, Ciani C, Licata NV, Micaelli M, Facen E, Tomaszewska W, Cerofolini L, Pérez-Ràfols A, Varela Rey M, Fragai M, Woodhoo A, Marinelli L, Arosio D, Bonomo I, Provenzani A, Seneci P. HuR-targeted agents: An insight into medicinal chemistry, biophysical, computational studies and pharmacological effects on cancer models. Adv Drug Deliv Rev 2022; 181:114088. [PMID: 34942276 DOI: 10.1016/j.addr.2021.114088] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 10/07/2021] [Accepted: 12/16/2021] [Indexed: 12/13/2022]
Abstract
The Human antigen R (HuR) protein is an RNA-binding protein, ubiquitously expressed in human tissues, that orchestrates target RNA maturation and processing both in the nucleus and in the cytoplasm. A survey of known modulators of the RNA-HuR interactions is followed by a description of its structure and molecular mechanism of action - RRM domains, interactions with RNA, dimerization, binding modes with naturally occurring and synthetic HuR inhibitors. Then, the review focuses on HuR as a validated molecular target in oncology and briefly describes its role in inflammation. Namely, we show ample evidence for the involvement of HuR in the hallmarks and enabling characteristics of cancer, reporting findings from in vitro and in vivo studies; and we provide abundant experimental proofs of a beneficial role for the inhibition of HuR-mRNA interactions through silencing (CRISPR, siRNA) or pharmacological inhibition (small molecule HuR inhibitors).
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Affiliation(s)
- Giulia Assoni
- Chemistry Department, University of Milan, Via Golgi 19, I-20133 Milan, Italy; Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Valeria La Pietra
- Department of Pharmacy, University of Napoli Federico II, Via D. Montesano 49, 80131 Napoli, Italy
| | - Rosangela Digilio
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Caterina Ciani
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Nausicaa Valentina Licata
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Mariachiara Micaelli
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Elisa Facen
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Weronika Tomaszewska
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Linda Cerofolini
- Magnetic Resonance Center (CERM), University of Florence and Interuniversity Consortium for Magnetic Resonance of Metalloproteins (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino (FI), Italy
| | - Anna Pérez-Ràfols
- Giotto Biotech S.R.L., Via Madonna del Piano 6, 50019 Sesto Fiorentino (FI), Italy
| | - Marta Varela Rey
- Gene Regulatory Control in Disease Group, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), Health Research Institute of Santiago de Compostela (IDIS), University of Santiago de Compostela, 15706 Santiago de Compostela, Spain
| | - Marco Fragai
- Magnetic Resonance Center (CERM), University of Florence and Interuniversity Consortium for Magnetic Resonance of Metalloproteins (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino (FI), Italy
| | - Ashwin Woodhoo
- Gene Regulatory Control in Disease Group, Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), Health Research Institute of Santiago de Compostela (IDIS), University of Santiago de Compostela, 15706 Santiago de Compostela, Spain; Department of Functional Biology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain; Galician Agency of Innovation (GAIN), Xunta de Galicia, Santiago de Compostela, Spain; Center for Cooperative Research in Biosciences (CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain; IKERBASQUE, Basque Foundation for Science, Bilbao 48013, Spain
| | - Luciana Marinelli
- Department of Pharmacy, University of Napoli Federico II, Via D. Montesano 49, 80131 Napoli, Italy
| | - Daniela Arosio
- Istituto di Scienze e Tecnologie Chimiche "G. Natta" (SCITEC), National Research Council (CNR), Via C. Golgi 19, I-20133 Milan, Italy
| | - Isabelle Bonomo
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, via Sommarive 9, 38123 Trento, Italy
| | - Alessandro Provenzani
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, via Sommarive 9, 38123 Trento, Italy.
| | - Pierfausto Seneci
- Chemistry Department, University of Milan, Via Golgi 19, I-20133 Milan, Italy.
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Umar SM, Patra S, Kashyap A, Dev J R A, Kumar L, Prasad CP. Quercetin Impairs HuR-Driven Progression and Migration of Triple Negative Breast Cancer (TNBC) Cells. Nutr Cancer 2021; 74:1497-1510. [PMID: 34278888 DOI: 10.1080/01635581.2021.1952628] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In the present study, we have explored the prognostic value of HuR gene as well as protein in breast cancers. Furthermore, we have also investigated the HuR therapeutic relevance in TNBCs, which is an aggressive breast cancer subtype. Using an online meta-analysis tool, we found that HuR protein overexpression positively correlates with reduced overall survival of TNBC patients (p = 0.028). Furthermore, we demonstrated that the TNBC breast cancer cell lines i.e., MDA-MB-231 and MDA-MB-468 are good model systems to study HuR protein, as they both exhibit a significant amount of cytoplasmic HuR (active form). Quercetin treatment significantly inhibited the cytoplasmic HuR in both TNBC cell lines. By using specific HuR siRNA, we established that quercetin-mediated inhibition of adhesion and migration of TNBC cells is dependent on HuR. Upon analyzing adhesion proteins i.e., β-catenin and CD44, we found that quercetin mediated effect on TNBC adhesion and migration was through the HuR-β-catenin axis and CD44, independently. Overall, the present results demonstrate that elevated HuR levels are associated with TNBC progression and relapse, and the ability of quercetin to inhibit cytoplasmic HuR protein provides a rationale for using it as an anticancer agent for the treatment of aggressive TNBCs.Supplemental data for this article is available online at at 10.1080/01635581.2021.1952628.
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Affiliation(s)
| | - Sushmita Patra
- Department of Medical Oncology, Dr. BRA IRCH, AIIMS, New Delhi, India
| | - Akanksha Kashyap
- Department of Medical Oncology, Dr. BRA IRCH, AIIMS, New Delhi, India
| | | | - Lalit Kumar
- Department of Medical Oncology, Dr. BRA IRCH, AIIMS, New Delhi, India
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Chen H, Padia R, Li T, Li Y, Li B, Jin L, Huang S. Signaling of MK2 sustains robust AP1 activity for triple negative breast cancer tumorigenesis through direct phosphorylation of JAB1. NPJ Breast Cancer 2021; 7:91. [PMID: 34244488 PMCID: PMC8270897 DOI: 10.1038/s41523-021-00300-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 06/24/2021] [Indexed: 02/06/2023] Open
Abstract
Triple negative breast cancer (TNBC) cells are generally more invasive than estrogen receptor-positive (ER + ) breast cancer cells. Consistent with the importance of activator protein 1 (AP1) transcription factors in invasion, AP1 activity is much higher in TNBC lines than ER + lines. In TNBC cells, robust AP1 activity is facilitated by both ERK and p38MAPK signaling pathways. While ERK signaling pathway regulates AP1 activity by controlling the abundance of AP1 transcription factors, p38MAPK signaling pathway does it by enhancing AP1 binding to AP1 sites without altering their abundance. Here, we show that p38MAPK regulation of AP1 activity involves both MAPKAPK2 (MK2) and JAB1, a known JUN-binding protein. MK2 not only interacts with JAB1 but also directly phosphorylates JAB1 at Ser177 in TNBC cells. Interestingly, Ser177 phosphorylation does not affect JAB1 and JUN interaction. Instead, interfering with p38MAPK signaling pathway or introducing an S to A point mutation at Ser177 of JAB1 reduces JUN recruitment to the AP1 sites in cyclin D1, urokinase plasminogen activator (uPA) and uPA receptor promoters. Moreover, knockdown of JAB1 diminishes >60% of AP1 transcriptional activity in TNBC cells. Taken together, these results indicate that MK2-mediated phosphorylation of JAB1 facilitates JUN recruitment to AP1 sites, thus augmenting AP1 activity. In line with the role of JAB1 in AP1 activity, silencing JAB1 leads to dramatic reduction in TNBC cell growth, in vitro invasion and in vivo tumor outgrowth. This study suggests that the p38MAPK-MK2 signaling pathway promotes TNBC tumorigenesis by sustaining robust AP1 activity.
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Affiliation(s)
- Haoming Chen
- grid.8547.e0000 0001 0125 2443The Ministry of Education Key Laboratory of Contemporary Anthropology, College of Life Science, Fudan University, Shanghai, China
| | - Ravi Padia
- grid.15276.370000 0004 1936 8091Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL USA
| | - Tao Li
- grid.15276.370000 0004 1936 8091Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL USA
| | - Yue Li
- grid.15276.370000 0004 1936 8091Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL USA
| | - Bin Li
- grid.15276.370000 0004 1936 8091Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL USA
| | - Lingtao Jin
- grid.15276.370000 0004 1936 8091Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL USA
| | - Shuang Huang
- grid.15276.370000 0004 1936 8091Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL USA
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Weiße J, Rosemann J, Krauspe V, Kappler M, Eckert AW, Haemmerle M, Gutschner T. RNA-Binding Proteins as Regulators of Migration, Invasion and Metastasis in Oral Squamous Cell Carcinoma. Int J Mol Sci 2020; 21:E6835. [PMID: 32957697 PMCID: PMC7555251 DOI: 10.3390/ijms21186835] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/14/2020] [Accepted: 09/17/2020] [Indexed: 02/06/2023] Open
Abstract
Nearly 7.5% of all human protein-coding genes have been assigned to the class of RNA-binding proteins (RBPs), and over the past decade, RBPs have been increasingly recognized as important regulators of molecular and cellular homeostasis. RBPs regulate the post-transcriptional processing of their target RNAs, i.e., alternative splicing, polyadenylation, stability and turnover, localization, or translation as well as editing and chemical modification, thereby tuning gene expression programs of diverse cellular processes such as cell survival and malignant spread. Importantly, metastases are the major cause of cancer-associated deaths in general, and particularly in oral cancers, which account for 2% of the global cancer mortality. However, the roles and architecture of RBPs and RBP-controlled expression networks during the diverse steps of the metastatic cascade are only incompletely understood. In this review, we will offer a brief overview about RBPs and their general contribution to post-transcriptional regulation of gene expression. Subsequently, we will highlight selected examples of RBPs that have been shown to play a role in oral cancer cell migration, invasion, and metastasis. Last but not least, we will present targeting strategies that have been developed to interfere with the function of some of these RBPs.
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Affiliation(s)
- Jonas Weiße
- Junior Research Group ‘RNA Biology and Pathogenesis’, Medical Faculty, Martin-Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany; (J.W.); (J.R.); (V.K.)
| | - Julia Rosemann
- Junior Research Group ‘RNA Biology and Pathogenesis’, Medical Faculty, Martin-Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany; (J.W.); (J.R.); (V.K.)
| | - Vanessa Krauspe
- Junior Research Group ‘RNA Biology and Pathogenesis’, Medical Faculty, Martin-Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany; (J.W.); (J.R.); (V.K.)
| | - Matthias Kappler
- Department of Oral and Maxillofacial Plastic Surgery, Medical Faculty, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany;
| | - Alexander W. Eckert
- Department of Cranio Maxillofacial Surgery, Paracelsus Medical University, 90471 Nuremberg, Germany;
| | - Monika Haemmerle
- Institute of Pathology, Section for Experimental Pathology, Medical Faculty, Martin-Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany;
| | - Tony Gutschner
- Junior Research Group ‘RNA Biology and Pathogenesis’, Medical Faculty, Martin-Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany; (J.W.); (J.R.); (V.K.)
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7
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Enhanced oncolytic activity of E4orf6-deficient adenovirus by facilitating nuclear export of HuR. Biochem Biophys Res Commun 2020; 529:494-499. [PMID: 32703457 DOI: 10.1016/j.bbrc.2020.04.147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 04/29/2020] [Indexed: 01/27/2023]
Abstract
An AU-rich element (ARE) is RNA element that enhances the rapid decay of mRNA. The RNA binding protein HuR stabilizes ARE-mRNA by exporting it to the cytoplasm. In most of cancer cells, HuR is exported to the cytoplasm and ARE-mRNA is stabilized. In addition, the viral gene product E4orf6 exports HuR to stabilize ARE-mRNA in adenovirus-infected cells and the stabilization is required for full virus replication. Previously we showed the oncolytic activity of E4orf6-deleted adenovirus dl355, which can replicate in cancer cells where ARE-mRNA is stabilized. In this study, we examined whether the further enhancement of HuR export can stimulate the replication and the oncolytic activity of dl355. We found that ethanol treatment promoted the cytoplasmic relocalization of HuR in cancer cells. In addition, the replication efficiency of dl355 increased in ethanol-treated cells, and in response, the cytolytic activity of the virus also increased in vitro and in vivo. Upregulation of a cleaved-PARP level in infected cells mediated by ethanol is suggesting that ethanol activated the apoptosis induced by dl355. IVa2 mRNA, the only ARE-mRNA among transcripts of adenovirus was augmented by ethanol treatment. These data indicate that the enhancement of ARE-mRNA stabilization as a result of ethanol treatment upregulates the oncolytic activity of dl355 and suggests that the combined use of an oncolytic adenovirus and ethanol treatment may be a good strategy for cancer therapy.
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Soni S, Anand P, Padwad YS. MAPKAPK2: the master regulator of RNA-binding proteins modulates transcript stability and tumor progression. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2019; 38:121. [PMID: 30850014 PMCID: PMC6408796 DOI: 10.1186/s13046-019-1115-1] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 02/21/2019] [Indexed: 01/09/2023]
Abstract
The p38 mitogen-activated protein kinase (p38MAPK) pathway has been implicated in a variety of pathological conditions including inflammation and metastasis. Post-transcriptional regulation of genes harboring adenine/uridine-rich elements (AREs) in their 3'-untranslated region (3'-UTR) is controlled by MAPK-activated protein kinase 2 (MAPKAPK2 or MK2), a downstream substrate of the p38MAPK. In response to diverse extracellular stimuli, MK2 influences crucial signaling events, regulates inflammatory cytokines, transcript stability and critical cellular processes. Expression of genes involved in these vital cellular cascades is controlled by subtle interactions in underlying molecular networks and post-transcriptional gene regulation that determines transcript fate in association with RNA-binding proteins (RBPs). Several RBPs associate with the 3'-UTRs of the target transcripts and regulate their expression via modulation of transcript stability. Although MK2 regulates important cellular phenomenon, yet its biological significance in tumor progression has not been well elucidated till date. In this review, we have highlighted in detail the importance of MK2 as the master regulator of RBPs and its role in the regulation of transcript stability, tumor progression, as well as the possibility of use of MK2 as a therapeutic target in tumor management.
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Affiliation(s)
- Sourabh Soni
- Pharmacology and Toxicology Laboratory, Food and Nutraceuticals Division, CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT), Palampur, Himachal Pradesh, India.,Academy of Scientific and Innovative Research, Chennai, Tamil Nadu, India
| | - Prince Anand
- Pharmacology and Toxicology Laboratory, Food and Nutraceuticals Division, CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT), Palampur, Himachal Pradesh, India.,Academy of Scientific and Innovative Research, Chennai, Tamil Nadu, India
| | - Yogendra S Padwad
- Pharmacology and Toxicology Laboratory, Food and Nutraceuticals Division, CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT), Palampur, Himachal Pradesh, India. .,Academy of Scientific and Innovative Research, Chennai, Tamil Nadu, India.
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Kakuguchi W, Nomura T, Kitamura T, Otsuguro S, Matsushita K, Sakaitani M, Maenaka K, Tei K. Suramin, screened from an approved drug library, inhibits HuR functions and attenuates malignant phenotype of oral cancer cells. Cancer Med 2018; 7:6269-6280. [PMID: 30449075 PMCID: PMC6308099 DOI: 10.1002/cam4.1877] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 07/20/2018] [Accepted: 10/24/2018] [Indexed: 01/16/2023] Open
Abstract
AU‐rich elements (ARE) exist in the 3′‐untranslated regions of the mRNA transcribed from cell growth‐related genes such as proto‐oncogenes, cyclin‐related genes, and growth factors. HuR binds and stabilizes ARE‐mRNA. HuR is expressed abundantly in cancer cells and related malignant phenotypes. HuR knockdown attenuates the malignant phenotype of oral cancer cells. In this study, we screened 1570 compounds in the approved drug library by differential scanning fluorimetry (DSF) to discover a HuR‐targeted compound. Firstly, 55 compounds were selected by DSF. Then, 8 compounds that showed a shift in the melting temperature value in a concentration‐dependent manner were selected by DSF. Of them, suramin, an anti‐trypanosomal drug, binds to HuR, exhibiting fast‐on and fast‐off kinetic behavior on surface plasmon resonance (SPR). We confirmed that suramin significantly decreased mRNA and protein expression of cyclin A2 and cyclin B1. The cyclin A2 and cyclin B1 mRNAs were destabilized by suramin. Furthermore, the motile and invasive activities of a tongue carcinoma cell line treated with suramin were markedly lower than those of control cells. The above findings suggest that suramin binds to HuR and inhibits its function. We also showed that the anticancer effects of suramin were caused by the inhibition of HuR function, indicating its potential as a novel therapeutic agent in the treatment of oral cancer. Our results suggest that suramin, via its different mechanism, may effectively suppress progressive oral cancer that cannot be controlled using other anticancer agents.
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Affiliation(s)
- Wataru Kakuguchi
- Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Takao Nomura
- Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Tetsuya Kitamura
- Department of Oral Pathology and Biology, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Satoko Otsuguro
- Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Kazuhiro Matsushita
- Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Masahiro Sakaitani
- Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Katsumi Maenaka
- Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Kanchu Tei
- Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
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Habiba U, Kuroshima T, Yanagawa-Matsuda A, Kitamura T, Chowdhury A, Jehung JP, Hossain E, Sano H, Kitagawa Y, Shindoh M, Higashino F. HuR translocation to the cytoplasm of cancer cells in actin-independent manner. Exp Cell Res 2018; 369:218-225. [PMID: 29807023 DOI: 10.1016/j.yexcr.2018.05.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/18/2018] [Accepted: 05/21/2018] [Indexed: 11/18/2022]
Abstract
Human antigen R (HuR) is a RNA-binding protein, which binds to the AU-rich element (ARE) in the 3'-untranslated region (3'-UTR) of certain mRNA and is involved in the export and stabilization of ARE-mRNA. HuR constitutively relocates to the cytoplasm in many cancer cells, however the mechanism of intracellular HuR trafficking is poorly understood. To address this question, we examined the functional role of the cytoskeleton in HuR relocalization. We tested the effect of actin depolymerizing macrolide latrunculin A or myosin II ATPase activity inhibitor blebbistatin for HuR relocalization induced by the vasoactive hormone Angiotensin II in cancer and control normal cells. Western blot and confocal imaging data revealed that both inhibitors attenuated the cytoplasmic HuR in normal cells but no such alteration was observed in cancer cells. Concomitant with changes in intracellular HuR localization, both inhibitors markedly decreased the accumulation and half-lives of HuR target ARE-mRNAs in normal cells, whereas no change was observed in cancer cells. Furthermore, co-immunoprecipitation experiments with HuR proteins revealed clear physical interaction with ß-actin only in normal cells. The current study is the first to verify that cancer cells can implicate a microfilament independent HuR transport. We hypothesized that when cytoskeleton structure is impaired, cancer cells can acquire an alternative HuR trafficking strategy.
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Affiliation(s)
- Umma Habiba
- Department of Oral Pathology and Biology, Hokkaido University Faculty of Dental Medicine and Graduate School of Dental Medicine, Sapporo, Japan
| | - Takeshi Kuroshima
- Department of Oral Diagnosis and Medicine, Hokkaido University Faculty of Dental Medicine and Graduate School of Dental Medicine, Sapporo, Japan
| | - Aya Yanagawa-Matsuda
- Department of Oral Pathology and Biology, Hokkaido University Faculty of Dental Medicine and Graduate School of Dental Medicine, Sapporo, Japan
| | - Tetsuya Kitamura
- Department of Oral Pathology and Biology, Hokkaido University Faculty of Dental Medicine and Graduate School of Dental Medicine, Sapporo, Japan
| | - Afma Chowdhury
- Department of Restorative Dentistry, Hokkaido University Faculty of Dental Medicine and Graduate School of Dental Medicine, Sapporo, Japan
| | - Jumond P Jehung
- Department of Restorative Dentistry, Hokkaido University Faculty of Dental Medicine and Graduate School of Dental Medicine, Sapporo, Japan
| | - Elora Hossain
- Department of Molecular Oncology, Hokkaido University Faculty of Dental Medicine and Graduate School of Biomedical Science and Engineering, 060-8586,North 13, West 7, Kita ku, Sapporo, Japan
| | - Hidehiko Sano
- Department of Restorative Dentistry, Hokkaido University Faculty of Dental Medicine and Graduate School of Dental Medicine, Sapporo, Japan
| | - Yoshimasa Kitagawa
- Department of Oral Diagnosis and Medicine, Hokkaido University Faculty of Dental Medicine and Graduate School of Dental Medicine, Sapporo, Japan
| | - Masanobu Shindoh
- Department of Oral Pathology and Biology, Hokkaido University Faculty of Dental Medicine and Graduate School of Dental Medicine, Sapporo, Japan
| | - Fumihiro Higashino
- Department of Oral Pathology and Biology, Hokkaido University Faculty of Dental Medicine and Graduate School of Dental Medicine, Sapporo, Japan; Department of Molecular Oncology, Hokkaido University Faculty of Dental Medicine and Graduate School of Biomedical Science and Engineering, 060-8586,North 13, West 7, Kita ku, Sapporo, Japan.
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11
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Clinical Significance and Biological Role of HuR in Head and Neck Carcinomas. DISEASE MARKERS 2018; 2018:4020937. [PMID: 29619127 PMCID: PMC5829322 DOI: 10.1155/2018/4020937] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/27/2017] [Indexed: 12/17/2022]
Abstract
Background Hu-antigen R (HuR) is a posttranscriptional regulator of several target mRNAs, implicated in carcinogenesis. This review aims to present the current evidence regarding the biological role and potential clinical significance of HuR in head and neck carcinomas. Methods The existing literature concerning HuR expression and function in head and neck carcinomas is critically presented and summarised. Results HuR is expressed in the majority of the examined samples, showing higher cytoplasmic levels in malignant or premalignant cases. Moreover, HuR modulates several genes implicated in biological processes important for malignant transformation, growth, and invasiveness. HuR seems to be an adverse prognosticator in patients with OSCCs, whereas a correlation with a more aggressive phenotype is reported in several types of carcinomas. Conclusions A consistent role of HuR in the carcinogenesis and progression of head and neck carcinomas is suggested; nevertheless, further studies are warranted to expand the present information.
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12
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Gauchotte G, Hergalant S, Vigouroux C, Casse JM, Houlgatte R, Kaoma T, Helle D, Brochin L, Rech F, Peyre M, Labrousse F, Vallar L, Guéant JL, Vignaud JM, Battaglia-Hsu SF. Cytoplasmic overexpression of RNA-binding protein HuR is a marker of poor prognosis in meningioma, and HuR knockdown decreases meningioma cell growth and resistance to hypoxia. J Pathol 2017; 242:421-434. [PMID: 28493484 DOI: 10.1002/path.4916] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 04/19/2017] [Accepted: 04/26/2017] [Indexed: 11/11/2022]
Abstract
HuR regulates cytoplasmic mRNA stability and translatability, and the HuR expression level has been shown to correlate with poor disease outcome in several cancer types; however, the prognostic value and potential pro-oncogenic properties of HuR in meningioma remain unclear. Thus, in the present study, we analysed 85 meningioma tissue samples to establish the relationship between HuR expression, tumour cell proliferation, and/or patient survival. In addition, we examined the anti-proliferative effects of HuR knockdown in two meningioma cell lines (IOMM-Lee and Ben-Men-1) and conducted transcriptome-wide analyses (IOMM-Lee cells) to elucidate the molecular consequences of HuR knockdown. The results of the present study showed HuR cytoplasmic expression to correlate positively with tumour grade (p = 1.2 × 10-8 ) and negatively with progression-free and overall survival (p = 0.01) time in human meningioma tissues. In vitro, siHuR-induced HuR knockdown was shown to reduce the growth of both Ben-Men-1 (p = 2 × 10-8 ) and IOMM-Lee (p = 4 × 10-9 ) cells. Transcriptome analyses revealed HuR knockdown in IOMM-Lee cells to deregulate the HIF1A signalling pathway (p = 1.5 × 10-6 ) and to up-regulate the expression of genes essential for the assembly of the cytoplasmic mRNA processing body, global genome nucleotide-excision repair, poly(A)-specific ribonuclease activity, the positive regulation of apoptosis and of cell cycle arrest, and the negative regulation of RNA splicing [p(FDR) < 0.001]. Interestingly, HuR knockdown under hypoxic culture conditions further potentiated the effects of HuR knockdown on cell growth, apoptosis, and HIF1A expression. We thus conclude that cytoplasmic HuR expression is a marker of poor prognosis in meningioma and that HuR is a promising potential therapeutic target for use in tumours refractory to standard therapies. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Guillaume Gauchotte
- INSERM U954, Faculty of Medicine, Université de Lorraine, Vandoeuvre-lès-Nancy, France.,Department of Pathology, CHRU, Nancy, France
| | - Sébastien Hergalant
- INSERM U954, Faculty of Medicine, Université de Lorraine, Vandoeuvre-lès-Nancy, France
| | | | - Jean-Matthieu Casse
- INSERM U954, Faculty of Medicine, Université de Lorraine, Vandoeuvre-lès-Nancy, France.,Department of Pathology, CHRU, Nancy, France
| | - Rémi Houlgatte
- INSERM U954, Faculty of Medicine, Université de Lorraine, Vandoeuvre-lès-Nancy, France
| | - Tony Kaoma
- Proteome and Genome Research Unit, Department of Oncology, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Déborah Helle
- INSERM U954, Faculty of Medicine, Université de Lorraine, Vandoeuvre-lès-Nancy, France
| | | | - Fabien Rech
- Department of Neurosurgery, CHRU, Nancy, France.,Institut des Neurosciences, INSERM U1051, Montpellier, France
| | - Matthieu Peyre
- Sorbonne Université, UPMC University Paris 06, INSERM, CNRS, UM 75, U 1127, UMR 7225, ICM, Paris, France.,Department of Neurosurgery, Groupe Hospitalier Pitié Salpêtrière, AP-HP, Paris, France
| | | | - Laurent Vallar
- Proteome and Genome Research Unit, Department of Oncology, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Jean-Louis Guéant
- INSERM U954, Faculty of Medicine, Université de Lorraine, Vandoeuvre-lès-Nancy, France.,M2TP, Division of Biochemistry and Molecular Biology, CHRU, Vandoeuvre-lès-Nancy, France
| | - Jean-Michel Vignaud
- INSERM U954, Faculty of Medicine, Université de Lorraine, Vandoeuvre-lès-Nancy, France.,Department of Pathology, CHRU, Nancy, France.,Centre de Ressources Biologiques, BB-0033-00035, CHRU Nancy, France
| | - Shyue-Fang Battaglia-Hsu
- INSERM U954, Faculty of Medicine, Université de Lorraine, Vandoeuvre-lès-Nancy, France.,M2TP, Division of Biochemistry and Molecular Biology, CHRU, Vandoeuvre-lès-Nancy, France
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13
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Habiba U, Kitamura T, Yanagawa-Matsuda A, Higashino F, Hida K, Totsuka Y, Shindoh M. HuR and podoplanin expression is associated with a high risk of malignant transformation in patients with oral preneoplastic lesions. Oncol Lett 2016; 12:3199-3207. [PMID: 27899983 PMCID: PMC5103919 DOI: 10.3892/ol.2016.5061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/12/2016] [Indexed: 11/22/2022] Open
Abstract
The risk of malignant transformation in oral preneoplastic lesions (OPLs) is challenging to assess. The objective of the present study was to determine the expression of ELAV like RNA binding protein 1 (HuR) and podoplanin in OPLs, and to evaluate the use of each protein as biomarkers for the risk assessment of malignant transformations. Immunohistochemistry for HuR and podoplanin was performed on the tissues of 51 patients with OPL, including cases of low grade dysplasia (LGD) and high grade dysplasia (HGD). The association between the protein expression patterns and clinicopathological parameters, including oral cancer free survival (OCFS) time, was analyzed during the follow-up period. HuR and podoplanin expression was observed in 28 (55%) and 36 (71%) of 51 patients, respectively. Kaplan-Meier analysis showed that the expression of HuR and podoplanin was associated with the risk of progression to oral cancer (P<0.05). Multivariate analysis revealed that HuR and podoplanin expression was associated with a 2.93-fold (95% confidence interval (CI), 0.98–10.34; P=0.055) and 2.06-fold (95% CI, 0.55–8.01; P=0.283) increase in risk of malignant transformation, respectively. The risk of OPL malignant transformation was considerably increased with the coexpression of HuR and podoplanin compared with the histological grading (95% CI, 1.64–23.59; P=0.005). The results of the present study demonstrated that the expression of HuR and podoplanin associates with malignant transformation and suggests that the proteins may be used as biomarkers to identify OPL patients with an increased risk of cancer development.
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Affiliation(s)
- Umma Habiba
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060-8586, Japan
| | - Tetsuya Kitamura
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060-8586, Japan
| | - Aya Yanagawa-Matsuda
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060-8586, Japan
| | - Fumihiro Higashino
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060-8586, Japan
| | - Kyoko Hida
- Department of Vascular Biology, Hokkaido University Institute for Genetic Medicine, Sapporo, Hokkaido 060-0815, Japan
| | - Yasunori Totsuka
- Department of Oral and Maxillofacial Surgery, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060-8586, Japan
| | - Masanobu Shindoh
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Sapporo, Hokkaido 060-8586, Japan
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14
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Wu T, Shi JX, Geng S, Zhou W, Shi Y, Su X. The MK2/HuR signaling pathway regulates TNF-α-induced ICAM-1 expression by promoting the stabilization of ICAM-1 mRNA. BMC Pulm Med 2016; 16:84. [PMID: 27215284 PMCID: PMC4877999 DOI: 10.1186/s12890-016-0247-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 03/08/2016] [Indexed: 01/02/2023] Open
Abstract
Background Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are characterized by acute lung inflammation. Intercellular adhesion molecule-1 (ICAM-1) and interleukin-8 (IL-8) play an important role in the development of these diseases. Mitogen-activated protein kinase (MAPK) p38/activated protein kinase 2 (MK2) regulates the expression of ICAM-1 and IL-8 in human lung microvascular endothelial cells (HPMECs) stimulated by tumor necrosis factor-α (TNF-α); however, the underlying molecular mechanism remains unclear. Here, we show that human antigen R (HuR), an RNA binding protein which binds preferentially to AU-rich elements (AREs) and stabilizes mRNAs, regulates TNF-α-induced ICAM-1 expression in the MK2/HuR signaling pathway. Method MK2 and HuR were silenced respectively in HPMECs and then HPMECs were stimulatied with TNF-α. Nucleo-cytoplasmic shuttling of HuR was detected by subcellular fractionation and confocal microscopy in MK2 knockdown HPMECs. In HuR silencing cells, protein and mRNA levels of ICAM-1 and IL-8 were measured by western blot analysis, ELISA and real-time PCR; mRNA stabilization were measured by real-time PCR after actinomycin D (ActD) blocking transcription. Furthermore, we performed neutrophil adhesion assay to assess the adhering capacity after HuR silencing. Results MK2 were subjected to a knockdown by interfering RNA, the mRNA and protein levels of HuR in human pulmonary microvascular endothelial cells (HPMECs) were not affected. However, after the stimulation of TNF-α, silencing MK2 inhibited HuR accumulation to cytoplasm from nucleus in HPMECs. Consequently, knockdown of HuR by RNA interference in HPMECs, there was reduction in the stability of ICAM-1 mRNA and ICAM-1 protein level. This event was accompanied by a decrease in the adhesion of neutrophils towards HPMECs. Nevertheless, HuR silencing had no effect on the mRNA and protein levels of IL-8. Conclusion These results indicate that MK2 post-transcriptionally regulates TNF-α-induced ICAM-1 expression by altering the cytoplasmic localization of HuR in HPMECs.
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Affiliation(s)
- Ting Wu
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, Nanjing University School of Medicine, 305 East Zhongshan Road, Nanjing, 210002, China
| | - Jia-Xin Shi
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, Nanjing University School of Medicine, 305 East Zhongshan Road, Nanjing, 210002, China.,Department of Respiratory Medicine, Lianyungang First People's Hospital, Affiliated Hospital of Xuzhou Medical College, Clinical Medical School of Nanjing Medical University, Lianyungang, 222002, China
| | - Shen Geng
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, Southern Medical University, Guangdong, 510000, China
| | - Wei Zhou
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, Nanjing University School of Medicine, 305 East Zhongshan Road, Nanjing, 210002, China
| | - Yi Shi
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, Nanjing University School of Medicine, 305 East Zhongshan Road, Nanjing, 210002, China.
| | - Xin Su
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, Nanjing University School of Medicine, 305 East Zhongshan Road, Nanjing, 210002, China.
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15
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Vigouroux C, Casse JM, Battaglia-Hsu SF, Brochin L, Luc A, Paris C, Lacomme S, Gueant JL, Vignaud JM, Gauchotte G. Methyl(R217)HuR and MCM6 are inversely correlated and are prognostic markers in non small cell lung carcinoma. Lung Cancer 2015; 89:189-96. [PMID: 26013954 DOI: 10.1016/j.lungcan.2015.05.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 05/02/2015] [Accepted: 05/09/2015] [Indexed: 01/24/2023]
Abstract
OBJECTIVES In non small cell lung carcinoma (NSCLC), earlier studies supported a prognostic value of intra-cytoplasmic HuR expression. HuR is a RNA binding protein previously shown to stimulate proliferation, but the link between HuR and proliferation in NSCLC has not yet been evaluated. The first objective of this study was to analyze the expression of HuR in a series of NSCLC and to correlate this to two proliferation markers, Ki-67 and MCM6. As potential post-transcriptional regulatory mechanisms for HuR expression, two miRNAs, miR16 and miR519, were also analyzed. Finally, because HuR methylation could be involved in its nucleocytoplasmic shuttling, the expression of methyl(R217)HuR and its relation to cancer survival were determined. MATERIALS AND METHODS Immunohistochemistry was used to evaluate the expression of HuR, methy(R217)HuR, Ki-67 and MCM6 in a series of 190 NSCLCs. The level of miR16 and miR519 was determined by qRT-PCR. RESULTS Higher cytoplasmic HuR staining was found in tumor vs. control paired normal lung (p<0.0001), but without correlation with survival. The level of methyl(R217)HuR was correlated both significantly with intra-cytoplasmic HuR staining (p<0.001), and overall survival (p=0.01). MCM6 correlated to a poorer overall survival (p<0.01). Both MCM6 and Ki-67 were positively correlated with HuR nuclear staining (p<0.0001 and p<0.001, respectively). On the contrary, MCM6 and Ki-67 correlated inversely to methyl(R217)HuR (p<0.001 and p=0.01, respectively). The levels of miR16 and miR519 were significantly lower in tumor tissue vs. paired normal lung (p<0.0001), but only miR519 correlated inversely to HuR expression (p=0.01). CONCLUSION While overall cytoplasmic HuR level was higher in tumor tissues, we found unexpectedly that methyl(R217)HuR was a marker of good prognosis. Furthermore, our data suggest that HuR level could be regulated by miR519. Finally, we demonstrated that Ki-67 and MCM6, both correlated with HuR, are valuable markers of poor prognosis in NSCLC.
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Affiliation(s)
| | - Jean-Matthieu Casse
- Department of Pathology, CHU Nancy, France; INSERM U954, Faculty of Medicine, Université de Lorraine, Nancy, France
| | - Shyue-Fang Battaglia-Hsu
- INSERM U954, Faculty of Medicine, Université de Lorraine, Nancy, France; Department of Molecular Biology and Biochemistry, CHU Nancy, France
| | | | - Amandine Luc
- INGRES, EA7298, Faculty of Medicine, Université de Lorraine, Nancy, France
| | - Christophe Paris
- INGRES, EA7298, Faculty of Medicine, Université de Lorraine, Nancy, France; Department of Occupational Diseases, CHU Nancy, France
| | | | - Jean-Louis Gueant
- INSERM U954, Faculty of Medicine, Université de Lorraine, Nancy, France; Department of Molecular Biology and Biochemistry, CHU Nancy, France
| | - Jean-Michel Vignaud
- Department of Pathology, CHU Nancy, France; INSERM U954, Faculty of Medicine, Université de Lorraine, Nancy, France; Centre de Ressources Biologiques, BB-0033-00035, CHU Nancy, France
| | - Guillaume Gauchotte
- Department of Pathology, CHU Nancy, France; INSERM U954, Faculty of Medicine, Université de Lorraine, Nancy, France.
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16
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Wang D, Wang M, Hu C, Shuang T, Zhou Y, Yan X. Expression of the ELAV-like protein HuR in the cytoplasm is associated with endometrial carcinoma progression. Tumour Biol 2014; 35:11939-47. [PMID: 25182852 DOI: 10.1007/s13277-014-2485-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 08/08/2014] [Indexed: 11/30/2022] Open
Abstract
Human antigen R (HuR) is an mRNA-binding factor that belongs to the embryonic lethal abnormal vision/Hu protein family which may function as a tumor maintenance gene in a variety of carcinomas. However, there is no study to analyze HuR expression in endometrial carcinoma. Here, we investigated the expression of HuR in endometrial carcinoma carcinogenesis and subsequent progression. The expression of HuR and estrogen receptor alpha (ER-α) protein was examined by immunohistochemistry on paraffin embedding specimens containing endometrial carcinoma and adjacent non-cancerous tissues. Short hairpin RNA against HuR was transfected to investigate the role of HuR in regulating the expression of ER-α and progression in endometrial carcinoma. Cell viability and cycle were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry, respectively. Apoptosis was examined by annexin V apoptosis assay. Our study result show that cytoplasmic HuR expression is more frequent in poorly differentiated carcinomas (p = 0.005), advanced stage (p = 0.020), and positive ER-α expression (p = 0.026). Three HuR short hairpin RNAs (shRNAs) were transfected into Ishikawa cells, and we selected the most effective shRNA for the following experiments. After the transfection, the ER-α protein level was decreased. Further, decreased expression of HuR resulted in the inhibition of proliferation and induced apoptosis in Ishikawa cells. Our results showed that HuR could be a causal factor of ER-α regulation in Ishikawa cells and thus may induce the hormone-dependent endometrial carcinoma.
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Affiliation(s)
- Dandan Wang
- Department of Gynecology and Obstetrics, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Shenyang, 110004, China
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17
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Kotta-Loizou I, Giaginis C, Theocharis S. Clinical significance of HuR expression in human malignancy. Med Oncol 2014; 31:161. [PMID: 25112469 DOI: 10.1007/s12032-014-0161-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 08/01/2014] [Indexed: 12/28/2022]
Abstract
Hu-antigen R (HuR) is an RNA-binding protein that regulates the stability, translation, and nucleus-to-cytoplasm translocation of target mRNAs. The aim of the present review was to summarize and present the currently available information in the English literature on HuR expression in various human tumors, verifying its possible clinical significance. HuR function is directly linked to its subcellular localization. In normal cells, HuR is mostly localized in the nucleus, while in malignant cells, an increase in cytoplasmic HuR levels has been noted, in both cell lines and tissue samples. Moreover, in malignancy, elevated HuR expression levels and cytoplasmic immunohistochemical pattern have been correlated with advanced clinicopathological parameters and altered expression levels of proteins implicated in neoplasia. Additionally, elevated HuR expression levels and mainly cytoplasmic immunohistochemical pattern were correlated with decreased patients' survival rate in various human tumors. HuR is a putative drug target for cancer therapy, since it is expressed ubiquitously in malignant clinical samples and has an apparently consistent role in tumor formation and progression.
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Affiliation(s)
- Ioly Kotta-Loizou
- Division of Cell and Molecular Biology, Imperial College London, London, UK
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18
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Habiba U, Kitamura T, Yanagawa-Matsuda A, Hida K, Higashino F, Ohiro Y, Totsuka Y, Shindoh M. Cytoplasmic expression of HuR may be a valuable diagnostic tool for determining the potential for malignant transformation of oral verrucous borderline lesions. Oncol Rep 2014; 31:1547-54. [PMID: 24534848 PMCID: PMC3975986 DOI: 10.3892/or.2014.3017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 01/20/2014] [Indexed: 01/10/2023] Open
Abstract
Oral verrucous carcinoma (OVC) is a low grade variant of oral squamous cell carcinoma, and oral verrucous hyperplasia (OVH) is a benign lesion without malignant features. However, pathologists are sometimes presented with borderline lesions and are indecisive as to diagnose them as benign or malignant. Thus, these lesions are tentatively termed oral verrucous lesions (OVLs). HuR is an ARE mRNA-binding protein, normally localized in the nucleus but cytoplasmic exportation is frequently observed in cancer cells. The present study aimed to elucidate whether expression of the HuR protein facilitates the diagnosis of true malignant lesions. Clinicopathological features were evaluated, and immunohistochemical analysis for p53, Ki67 and HuR proteins was performed in 48 cases of OVH, OVC and OVL, and the outcomes were correlated using appropriate statistical analysis. The association of these three proteins in relation to malignant transformation was analyzed after a 3-year follow-up of 25 OVL cases. The basal characteristics (age, gender and location) of all cases had no significant association with the types of lesions. Gingiva (39.4%) was the common site for all lesions. Distribution of the examined proteins had a significant association with the lesions. As compared with the OVLs, the number of immunostained-positive cells was significantly higher in the OVCs and lower in the OVH cases. During follow-up, 24% of the OVLs underwent malignant transformation for which high HuR expression and a diffuse staining pattern in the epithelium were observed. Taken together, the high degree of HuR expression with diffuse staining pattern in the epithelium may be an effective diagnostic tool that determines the potential of OVLs for malignant transformation.
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Affiliation(s)
- Umma Habiba
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Kita-ku, Sapporo 060-8586, Japan
| | - Tetsuya Kitamura
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Kita-ku, Sapporo 060-8586, Japan
| | - Aya Yanagawa-Matsuda
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Kita-ku, Sapporo 060-8586, Japan
| | - Kyoko Hida
- Department of Vascular Biology, Hokkaido University Graduate School of Dental Medicine, Kita-ku, Sapporo 060-8586, Japan
| | - Fumihiro Higashino
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Kita-ku, Sapporo 060-8586, Japan
| | - Yoichi Ohiro
- Department of Oral and Maxillofacial Surgery, Hokkaido University Graduate School of Dental Medicine, Kita-ku, Sapporo 060-8586, Japan
| | - Yasunori Totsuka
- Department of Oral and Maxillofacial Surgery, Hokkaido University Graduate School of Dental Medicine, Kita-ku, Sapporo 060-8586, Japan
| | - Masanobu Shindoh
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Kita-ku, Sapporo 060-8586, Japan
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Imamachi K, Higashino F, Kitamura T, Kakuguchi W, Yanagawa-Matsuda A, Ishikawa M, Kitagawa Y, Totsuka Y, Shindoh M. pp32r1 controls the decay of the RNA-binding protein HuR. Oncol Rep 2013; 31:1103-8. [PMID: 24398589 DOI: 10.3892/or.2013.2956] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 11/05/2013] [Indexed: 11/05/2022] Open
Abstract
pp32 is a tumor suppressor and is one of the associated proteins of the RNA-binding protein HuR. The pp32-HuR complex is exported to the cytoplasm of cells under stress conditions, and HuR is degraded by caspases in the cytoplasm. In the present study, we examined the role of pp32r1, a member of the pp32 family that has oncogenic properties, in the decay of HuR. pp32r1 was found to be abundantly expressed in cancer cells, and overexpression of pp32r1 induced colony formation in soft-agar. pp32r1 was expressed in both the nucleus and cytoplasm, whereas pp32 was predominantly localized in the nucleus. Even with lethal stress such as staurosporine (STS), HuR in the cytoplasm was never downregulated, and caspase-3 activity was inhibited when cells expressed pp32r1. pp32r1 bound to HuR without interacting with pp32. In cancer cells, HuR survived in the cytoplasm of cells overexpressing pp32r1, although HuR was not expressed in the cytoplasm of pp32-expressing cells, similar to lethal stress conditions. Taken together, these results indicate that pp32r1 binds to HuR to avoid the caspase-mediated decay of HuR in the cytoplasm of cells. We suggest that this function contributes to the oncogenic activity of pp32r1.
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Affiliation(s)
- Kenji Imamachi
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Sapporo 060-8586, Japan
| | - Fumihiro Higashino
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Sapporo 060-8586, Japan
| | - Tetsuya Kitamura
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Sapporo 060-8586, Japan
| | - Wataru Kakuguchi
- Department of Oral and Maxillofacial Surgery, Hokkaido University Graduate School of Dental Medicine, Sapporo 060-8586, Japan
| | - Aya Yanagawa-Matsuda
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Sapporo 060-8586, Japan
| | - Makoto Ishikawa
- Department of Oral Diagnosis and Medicine, Hokkaido University Graduate School of Dental Medicine, Sapporo 060-8586, Japan
| | - Yoshimasa Kitagawa
- Department of Oral Diagnosis and Medicine, Hokkaido University Graduate School of Dental Medicine, Sapporo 060-8586, Japan
| | - Yasunori Totsuka
- Department of Oral and Maxillofacial Surgery, Hokkaido University Graduate School of Dental Medicine, Sapporo 060-8586, Japan
| | - Masanobu Shindoh
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Sapporo 060-8586, Japan
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20
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Zhang C, Xue G, Bi J, Geng M, Chu H, Guan Y, Wang J, Wang B. Cytoplasmic expression of the ELAV-like protein HuR as a potential prognostic marker in esophageal squamous cell carcinoma. Tumour Biol 2013; 35:73-80. [PMID: 23873103 DOI: 10.1007/s13277-013-1008-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 07/08/2013] [Indexed: 02/06/2023] Open
Abstract
Esophageal squamous cell carcinoma (ESCC) is one of the most frequent cancers and a leading cause of death from cancer in China. The human ELAV-like protein HuR has been found to contribute to cancer development and progression through stabilizing a group of cellular mRNAs of cancer-related genes. In this study, we investigated the expression of HuR in a cohort of ESCC patients using immunohistochemical staining. HuR detected in the cytoplasm of cancer cells was positive in 46.6% of 58 ESCC specimens; 75.9% of these specimens had nuclear immunoreactivity for HuR. Cytoplasmic HuR expression was higher in cancer tissues compared to 20 matched adjacent noncancerous tissues. A clinicopathological study showed that cytoplasmic HuR expression was positively associated with lymph node metastasis, depth of tumor invasion, and advanced stage, whereas nuclear HuR expression was not correlated with any clinicopathological factors. Patients positive for cytoplasmic HuR expression had a cumulative 5-year survival rate of 25.3%, whereas it was 43.8% for patients negative for cytoplasmic HuR expression. In a multivariate analysis, cytoplasmic HuR expression was an independent prognostic factor, whereas nuclear positivity for HuR was not. Our results indicate that high cytoplasmic HuR expression is associated with positive lymph node metastasis, deep tumor invasion, high stage, and poor survival in ESCC. Thus, HuR is the first mRNA stability protein whose expression is associated with poor survival in esophageal cancer.
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Affiliation(s)
- Cong Zhang
- Department of Oncology, General Hospital, Jinan Command of the People's Liberation Army, Shifan Street 25, Tianqiao District, Jinan, 250031, China
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21
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Zhu Z, Wang B, Bi J, Zhang C, Guo Y, Chu H, Liang X, Zhong C, Wang J. Cytoplasmic HuR expression correlates with P-gp, HER-2 positivity, and poor outcome in breast cancer. Tumour Biol 2013; 34:2299-308. [PMID: 23605320 DOI: 10.1007/s13277-013-0774-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 03/25/2013] [Indexed: 12/18/2022] Open
Abstract
HuR is an ubiquitously expressed RNA-binding protein that stabilizes messenger RNA and regulates translation. This protein has been shown to play an important role in carcinogenesis and cancer progression. P-glycoprotein (P-gp) is the product of the multidrug resistance 1 gene, and the overexpression of P-gp induces multidrug resistance and represents a major obstacle in cancer chemotherapy. The purpose of this study was to determine the expression of HuR and P-gp in human breast cancer tissues and analyze the relationship between HuR or P-gp expression and the clinical-pathological variables and patient outcomes. Immunohistochemistry was used to determine HuR and P-gp expression in 82 human breast cancer tissues and 20 matched adjacent noncancerous tissues. Additionally, 16 benign breast tumor samples were used as controls. The overexpression of cytoplasmic HuR was found in breast cancer but not in the matched adjacent noncancerous tissues or benign breast tumors. The expression levels of cytoplasmic HuR were significantly associated with increased age, high nuclear grade, and the positive expression of the ER, PR, and HER-2/neu. HuR was also associated with the expression of P-gp protein. Furthermore, univariate analysis indicates that patients with high expression levels of cytoplasmic HuR or P-gp had significantly reduced survival compared to patients with low expression levels. A multivariate analysis showed that age at diagnosis, nuclear grade, and cytoplasmic HuR positivity were independent indicators for disease-free survival and overall survival in patients with breast cancer. In conclusion, cytoplasmic HuR expression detected by immunohistochemical staining is a negative prognostic indicator for survival in patients with breast cancer.
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Affiliation(s)
- Zhongpeng Zhu
- Department of Oncology, General Hospital, Jinan Command of People's Liberation Army, Shifan Street 25, Tianqiao District, Jinan, 250031, China
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22
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Mishra R. Cell cycle-regulatory cyclins and their deregulation in oral cancer. Oral Oncol 2013; 49:475-81. [PMID: 23434055 DOI: 10.1016/j.oraloncology.2013.01.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 01/24/2013] [Accepted: 01/25/2013] [Indexed: 11/26/2022]
Abstract
Oral cancer is a growth-related disorder, and cyclins are the prime regulators of cell division. Cyclins are associated with the pathogenesis of oral cancer and are considered valuable biomarkers for diagnosis and prognosis. These important molecules are regulated in many ways to achieve a gain in function and are involved in promoting neoplastic growth. While the causes of most cyclin overexpression are varied, these cyclins may be induced by buccal mucosal insult mainly with carcinogens that alter various pathways propelling oral cancer. Substantial experimental evidences support a link between oncogenic signaling pathways and the deregulation of cyclins in oral cancer. This review focuses on the mechanisms by which cyclins are regulated and promote oral oncogenesis.
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Affiliation(s)
- Rajakishore Mishra
- Centre for Life Sciences, School of Natural Sciences, Central University of Jharkhand, Ratu-Lohardaga Road, Brambe, Ranchi 835 205, Jharkhand, India.
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Shen DW, Pouliot LM, Gillet JP, Ma W, Johnson AC, Hall MD, Gottesman MM. The transcription factor GCF2 is an upstream repressor of the small GTPAse RhoA, regulating membrane protein trafficking, sensitivity to doxorubicin, and resistance to cisplatin. Mol Pharm 2012; 9:1822-33. [PMID: 22571463 PMCID: PMC3367311 DOI: 10.1021/mp300153z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Our aim was to explore the involvement of the transcriptional suppressor GCF2 in silencing RhoA, disorganization of the cytoskeleton, mislocalization of MRP1, and sensitivity to anticancer agents as an upstream gene target in cancer therapy. Increased expression of GCF2 was found in human cisplatin-resistant cells, and overexpression in GCF2-transfected cells results in loss of RhoA expression and disruption of the actin/filamin network. In consequence, the membrane transporter MRP1 was internalized from the cell surface into the cytoplasm, rendering cells sensitive to doxorubicin by more than 10-fold due to increased accumulation of doxorubicin in the cells. The GCF2 transfectants also showed reduced accumulation of cisplatin and increased resistance. siRNA targeted to GCF2 suppressed the expression of GCF2 in cisplatin-resistant cells, reactivated RhoA expression, and restored the fine structure of actin microfilaments. MRP1 was also relocated to the cell surface. siRNA targeted to RhoA increased resistance 3-fold in KB-3-1 and KB-CP.5 cells. These data for the first time demonstrate a novel complex regulatory pathway downstream from GCF2 involving the small GTPase RhoA, actin/filamin dynamics, and membrane protein trafficking. This pathway mediates diverse responses to cytotoxic compounds, and also provides a molecular basis for further investigation into the pleiotropic resistance mechanism at play in cisplatin-resistant cells.
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Affiliation(s)
- Ding-Wu Shen
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Lynn M. Pouliot
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Jean-Pierre Gillet
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Wenting Ma
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Alfred C. Johnson
- Office of the Director, National Institutes of Health, Bethesda, MD 20892
| | - Matthew D. Hall
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Michael M. Gottesman
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
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24
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Versatility of RNA-Binding Proteins in Cancer. Comp Funct Genomics 2012; 2012:178525. [PMID: 22666083 PMCID: PMC3359819 DOI: 10.1155/2012/178525] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 02/28/2012] [Indexed: 01/22/2023] Open
Abstract
Posttranscriptional gene regulation is a rapid and efficient process to adjust the proteome of a cell to a changing environment. RNA-binding proteins (RBPs) are the master regulators of mRNA processing and translation and are often aberrantly expressed in cancer. In addition to well-studied transcription factors, RBPs are emerging as fundamental players in tumor development. RBPs and their mRNA targets form a complex network that plays a crucial role in tumorigenesis. This paper describes mechanisms by which RBPs influence the expression of well-known oncogenes, focusing on precise examples that illustrate the versatility of RBPs in posttranscriptional control of cancer development. RBPs appeared very early in evolution, and new RNA-binding domains and combinations of them were generated in more complex organisms. The identification of RBPs, their mRNA targets, and their mechanism of action have provided novel potential targets for cancer therapy.
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25
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Shi JX, Su X, Xu J, Zhang WY, Shi Y. HuR post-transcriptionally regulates TNF-α-induced IL-6 expression in human pulmonary microvascular endothelial cells mainly via tristetraprolin. Respir Physiol Neurobiol 2012; 181:154-61. [PMID: 22426177 DOI: 10.1016/j.resp.2012.02.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 02/27/2012] [Accepted: 02/29/2012] [Indexed: 10/28/2022]
Abstract
HuR and tristetraprolin (TTP) are both RNA-binding proteins, which are characterized as binding to the AU-rich elements (AREs) in the 3'-untranslated regions (3'-UTRs) of target mRNAs. Studies have shown that some ARE-containing mRNAs are stabilized by HuR, whereas are destabilized by TTP. Our previous study showed that HuR upregulated tumor necrosis factor-α (TNF-α)-induced interleukin-6 (IL-6) expression by stabilizing its mRNA in human pulmonary microvascular endothelial cells (HPMECs). Considering IL-6 mRNA has AREs, we decided to examine whether TTP was also involved in the regulation of TNF-α-induced IL-6 expression in HPMECs and whether HuR and TTP influenced each other at protein and mRNA level. Here, we report that TTP silencing increased IL-6 levels. HuR silencing increased TTP expression. TTP had no effect on HuR expression and subcellular localization. Compared to TTP silencing alone, double knockdown of HuR and TTP did not significantly reduce IL-6 release. The RNA-binding protein immunoprecipitation (RIP) results further showed that TTP but not HuR bound to intracellular IL-6 mRNA in HPMECs. We demonstrate for the first time that HuR post-transcriptionally regulates IL-6 expression mainly via TTP.
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Affiliation(s)
- Jia-Xin Shi
- Department of Respiratory and Critical Care Medicine, Jinling Hospital, Nanjing University School of Medicine, 305 East Zhongshan Road, Nanjing 210002, China
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26
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Barker A, Epis MR, Porter CJ, Hopkins BR, Wilce MCJ, Wilce JA, Giles KM, Leedman PJ. Sequence requirements for RNA binding by HuR and AUF1. J Biochem 2012; 151:423-37. [PMID: 22368252 DOI: 10.1093/jb/mvs010] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The stability of RNAs bearing AU-rich elements in their 3'-UTRs, and thus the level of expression of their protein products, is regulated by interactions with cytoplasmic RNA-binding proteins. Binding by HuR generally leads to mRNA stabilization and increased protein production, whereas binding by AUF1 isoforms generally lead to rapid degradation of the mRNA and reduced protein production. The exact nature of the interplay between these and other RNA-binding proteins remains unclear, although recent studies have shown close interactions between them and even suggested competition between the two for binding to their cognate recognition sequences. Other recent reports have suggested that the sequences recognized by the two proteins are different. We therefore performed a detailed in vitro analysis of the binding site(s) for HuR and AUF1 present in androgen receptor mRNA to define their exact target sequences, and show that the same sequence is contacted by both proteins. Furthermore, we analysed a proposed HuR target within the 3'-UTR of MTA1 mRNA, and show that the contacted bases lie outside of the postulated motif and are a better match to a classical ARE than the postulated motif. The defining features of these HuR binding sites are their U-richness and single strandedness.
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Affiliation(s)
- Andrew Barker
- Laboratory for Cancer Medicine, Centre for Medical Research, Western Australian Institute for Medical Research, Perth, WA, 6000, Australia
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27
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Jones B, Koch AE, Ahmed S. Pathological role of fractalkine/CX3CL1 in rheumatic diseases: a unique chemokine with multiple functions. Front Immunol 2012; 2:82. [PMID: 22566871 PMCID: PMC3341950 DOI: 10.3389/fimmu.2011.00082] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 12/06/2011] [Indexed: 12/27/2022] Open
Abstract
Understanding rheumatic diseases from the perspective of chemokine biology has shaped and will continue to shape our approach for targeted drug design. Among different kinds of chemokines, fractalkine/CX3CL1 has been found to play an important role in inflammation, portraying unique functional, and structural characteristics. This review summarizes the emerging role of fractalkine/CX3CL1 from a functional and clinical perspective and provides evidence to validate it as a potential therapeutic target in rheumatic diseases such as rheumatoid arthritis, Sjögren's syndrome, systemic lupus erythematosus, scleroderma, as well as diseases related to vascular inflammation. From this, recent studies investigating potential therapeutic agents against fractalkine/CX3CL1's role in pathology have shown promise.
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Affiliation(s)
- Brian Jones
- Department of Pharmacology, College of Pharmacy and Pharmaceutical Sciences, The University of Toledo Toledo, OH, USA
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28
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Abstract
The cytoplasmic events that control mammalian gene expression, primarily mRNA stability and translation, potently influence the cellular response to internal and external signals. The ubiquitous RNA-binding protein (RBP) HuR is one of the best-studied regulators of cytoplasmic mRNA fate. Through its post-transcriptional influence on specific target mRNAs, HuR can alter the cellular response to proliferative, stress, apoptotic, differentiation, senescence, inflammatory and immune stimuli. In light of its central role in important cellular functions, HuR's role in diseases in which these responses are aberrant is increasingly appreciated. Here, we review the mechanisms that control HuR function, its influence on target mRNAs, and how impairment in HuR-governed gene expression programs impact upon different disease processes. We focus on HuR's well-recognized implication in cancer and chronic inflammation, and discuss emerging studies linking HuR to cardiovascular, neurological, and muscular pathologies. We also discuss the progress, potential, and challenges of targeting HuR therapeutically.
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Affiliation(s)
- Subramanya Srikantan
- Laboratory of Molecular Biology and Immunology, NIA-IRP, NIH, Baltimore, MD 21224, USA
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29
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Talwar S, Jin J, Carroll B, Liu A, Gillespie MB, Palanisamy V. Caspase-mediated cleavage of RNA-binding protein HuR regulates c-Myc protein expression after hypoxic stress. J Biol Chem 2011; 286:32333-43. [PMID: 21795698 DOI: 10.1074/jbc.m111.255927] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Altered expression of RNA-binding proteins modulates gene expression in association with mRNAs encoding many proto-oncogenes, cytokines, chemokines, and proinflammatory factors. Hu antigen R (HuR), a ubiquitously expressed protein, controls a range of cellular functions such as tumor progression, apoptosis, invasion, and metastasis by stabilizing the AU-rich element located at the 3'-untranslated region (UTR) of target mRNAs. Although significant progress has been made in understanding HuR regulation in gene expression, little is known about how HuR undergoes post-translational modifications and recruits target mRNAs during hypoxic stress. Here, we report that during CoCl(2)-induced hypoxic stress, HuR is significantly overexpressed and undergoes caspase-dependent cleavage in head and neck squamous cell carcinoma cells. Unexpectedly, the HuR-cleavage product 1 (HuR-CP1) was found to strongly associate with the 3'-UTR of c-myc mRNA and block mRNA translation. The binding efficiency of HuR to the 3'-UTR of c-myc mRNA was confirmed using ribonucleoprotein immunoprecipitation and site-directed mutagenesis at the AU-rich element sequences of the c-myc mRNA. Overexpression of a non-cleavable isoform, HuR-D226A, revealed a potent dominant-negative effect, repressing cleavage of endogenous HuR and promoting cell viability. Surprisingly, under hypoxia, siRNA knockdown of HuR elevated c-Myc protein expression. These findings suggest an important role for HuR in hypoxia, and we may have revealed a novel post-transcriptional mechanism that controls c-Myc expression in oral cancer progression.
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Affiliation(s)
- Sudha Talwar
- Department of Craniofacial Biology, College of Dental Medicine, Medical University of SouthCarolina, Charleston, South Carolina 29425, USA
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Vlasova-St Louis I, Bohjanen PR. Coordinate regulation of mRNA decay networks by GU-rich elements and CELF1. Curr Opin Genet Dev 2011; 21:444-51. [PMID: 21497082 DOI: 10.1016/j.gde.2011.03.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 03/21/2011] [Indexed: 01/03/2023]
Abstract
The GU-rich element (GRE) was identified as a conserved sequence enriched in the 3' UTR of human transcripts that exhibited rapid mRNA turnover. In mammalian cells, binding to GREs by the protein CELF1 coordinates mRNA decay of networks of transcripts involved in cell growth, migration, and apoptosis. Depending on the context, GREs and CELF1 also regulate pre-mRNA splicing and translation. GREs are highly conserved throughout evolution and play important roles in the development of organisms ranging from worms to man. In humans, abnormal GRE-mediated regulation contributes to disease states and cancer. Thus, GREs and CELF proteins serve critical functions in gene expression regulation and define an important evolutionarily conserved posttranscriptional regulatory network.
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Affiliation(s)
- Irina Vlasova-St Louis
- Department of Microbiology, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota, Minneapolis, MN, USA
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31
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Viral-mediated stabilization of AU-rich element containing mRNA contributes to cell transformation. Oncogene 2011; 30:2912-20. [PMID: 21317928 DOI: 10.1038/onc.2011.14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
E4orf6 is one of the oncogene products of adenovirus, and it also has an important role for transportation of cellular and viral messenger RNA (mRNA) during the late phase of virus infection. We previously revealed that E4orf6 controls the fate of AU-rich element (ARE) containing mRNA by perturbing the chromosome maintenance region 1-dependent export mechanism. Here, we show that E4orf6 stabilizes ARE-mRNA through the region required for its oncogenic activity and ubiquitin E3 ligase assembly. Cells that failed to stabilize ARE-mRNA after HuR knockdown were unable to produce colonies in soft agar, even when E4orf6 was expressed. Furthermore, the stabilized ARE-mRNA induced the transformation of rodent immortalized cells. These findings indicate that stabilized ARE-mRNA is necessary, if not all, for the oncogenic activity of E4orf6 and has the potential to transform cells, at least under a certain condition.
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HuR keeps an angiogenic switch on by stabilising mRNA of VEGF and COX-2 in tumour endothelium. Br J Cancer 2011; 104:819-29. [PMID: 21285980 PMCID: PMC3048211 DOI: 10.1038/bjc.2011.20] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background: Tumour stromal cells differ from its normal counterpart. We have shown that tumour endothelial cells (TECs) isolated from tumour tissues are also abnormal. Furthermore, we found that mRNAs of vascular endothelial growth factor-A (VEGF-A) and cyclooxygenase-2 (COX-2) were upregulated in TECs. Vascular endothelial growth factor-A and COX-2 are angiogenic factors and their mRNAs contain an AU-rich element (ARE). AU-rich element-containing mRNAs are reportedly stabilised by Hu antigen R (HuR), which is exported to the cytoplasm. Methods: Normal endothelial cell (NEC) and two types of TECs were isolated. We evaluated the correlation of HuR and accumulation of VEGF-A and COX-2 mRNAs in TECs and effects of HuR on biological phenotypes of TECs. Results: The HuR protein was accumulated in the cytoplasm of TECs, but not in NECs. Vascular endothelial growth factor-A and COX-2 mRNA levels decreased due to HuR knockdown and it was shown that these ARE-mRNA were bound to HuR in TECs. Furthermore, HuR knockdown inhibited cell survival, random motility, tube formation, and Akt phosphorylation in TECs. Conclusion: Hu antigen R is associated with the upregulation of VEGF-A and COX-2 mRNA in TECs, and has an important role in keeping an angiogenic switch on, through activating angiogenic phenotype in tumour endothelium.
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Wang J, Wang B, Bi J, Zhang C. Cytoplasmic HuR expression correlates with angiogenesis, lymphangiogenesis, and poor outcome in lung cancer. Med Oncol 2010; 28 Suppl 1:S577-85. [PMID: 21046284 DOI: 10.1007/s12032-010-9734-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 10/22/2010] [Indexed: 12/21/2022]
Abstract
HuR is a ubiquitously expressed RNA-binding protein that stabilizes the mRNAs of certain genes and regulates the translation to proteins. Elevated cytoplasmic expression of HuR has been suggested to be associated with reduced survival in a wide variety of human carcinomas. However, the clinical significance of HuR expression in lung cancer remains unknown. In this study, we examined HuR expression in 132 patients with non-small cell lung carcinoma (NSCLC) by means of immunohistochemistry and correlated clinicopathologic data, lymphatic microvessel density (LVD), or microvessel density (MVD) with HuR immunostaining. HuR was expressed in 80.3% (106/132) of cases and was predominantly localized in the nucleus. Cytoplasmic HuR expression occurred in 40.9% (54/132) of NSCLC specimens and was associated with high MVD and LVD. In univariate analysis, cytoplasmic HuR, but not nuclear HuR expression was found to significantly influence the relapse-free survival and overall survival. In addition, cytoplasmic expression of HuR was identified as an independent prognostic factor for survival in multivariate analysis. Our data provide evidence for a clinically prognostic role of HuR in NSCLC and demonstrate an association between HuR expression, and angiogenesis and lymphangiogenesis.
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Affiliation(s)
- Jun Wang
- Department of Oncology, General Hospital, Jinan Command of the People's Liberation Army, 250031 Jinan, China.
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34
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Abdelmohsen K, Gorospe M. Posttranscriptional regulation of cancer traits by HuR. WILEY INTERDISCIPLINARY REVIEWS. RNA 2010; 1:214-29. [PMID: 21935886 PMCID: PMC3808850 DOI: 10.1002/wrna.4] [Citation(s) in RCA: 326] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cancer-related gene expression programs are strongly influenced by posttranscriptional mechanisms. The RNA-binding protein HuR is highly abundant in many cancers. Numerous HuR-regulated mRNAs encode proteins implicated in carcinogenesis. Here, we review the collections of HuR target mRNAs that encode proteins responsible for implementing five major cancer traits. By interacting with specific mRNA subsets, HuR enhances the levels of proteins that (1) promote cell proliferation, (2) increase cell survival, (3) elevate local angiogenesis, (4) help the cancer cell evade immune recognition, and (5) facilitate cancer cell invasion and metastasis. We propose that HuR exerts a tumorigenic function by enabling these cancer phenotypes. We discuss evidence that links HuR to several specific cancers and suggests its potential usefulness in cancer diagnosis, prognosis, and therapy.
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35
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Elshamy WM. Induction of breast cancer in wild type p53 cells by BRCA1-IRIS overexpression. HAWAII MEDICAL JOURNAL 2010; 69:200-201. [PMID: 20845286 PMCID: PMC3118025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Cells ability to evade cell death and to proliferate post geno-/cell-toxic stresses, likely leads to formation of cancer. Activation of p38MAPK and p53 following these stresses help protect cells against cancer development by initiating apoptosis. The duration of p38MAPK and p53 activation is regulated by the WIP1 phosphatase. BRCA1-IRIS triggers WIP1 expression in p53-dependent and -independent manner. BRCA1-IRIS triggers the expression and cytoplasmic localization of the mRNA stabilization and translation inducer, HuR that binds p53 and PPM1D mRNA. Hence, BRCA1-IRIS overexpression inactivates p38MAPK and/or p53 by upregulating WIP1 expression. BRCA1-IRIS abrogation of the homeostatic balance maintained by p38MAPK-p53-WIP1 pathway suppressed cell death induced by a lethal dose of UVC, high dosages of etoposide or H2O2, and allowed cells to survive and proliferate post geno-/cell-toxic stresses. This mechanism represents a new link between geno-/cell-toxic stress and aggressive breast cancer formation in p53 wild-type cells.
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Affiliation(s)
- Wael M Elshamy
- Cancer Research Center of Hawaii, University of Hawaii, Honolulu, Hawaii 96813, USA
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36
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BRCA1-IRIS overexpression abrogates UV-induced p38MAPK/p53 and promotes proliferation of damaged cells. Oncogene 2010; 29:5274-85. [DOI: 10.1038/onc.2010.262] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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37
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Kakuguchi W, Kitamura T, Kuroshima T, Ishikawa M, Kitagawa Y, Totsuka Y, Shindoh M, Higashino F. HuR knockdown changes the oncogenic potential of oral cancer cells. Mol Cancer Res 2010; 8:520-8. [PMID: 20332213 DOI: 10.1158/1541-7786.mcr-09-0367] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
HuR binds to AU-rich element-containing mRNA to protect them from rapid degradation. Here, we show that knockdown of HuR changes the oncogenic properties of oral cancer cells. Oral squamous cell carcinoma cell lines, HSC-3 and Ca9.22, which express HuR protein and cytoplasmic AU-rich element mRNA more abundantly than normal cells, were subjected to HuR knockdown. In the HuR-knockdown cancer cells, the cytoplasmic expression of c-fos, c-myc, and COX-2 mRNAs was inhibited compared with those in cells that had been transfected with a control small interfering RNA, and the half-lives of these mRNAs were shorter than those of their counterparts in the control cells. HuR-knockdown cells failed to make colonies in soft agar, suggesting that the cells had lost their ability for anchorage-independent cell growth. Additionally, the motile and invasive activities of the cells decreased remarkably by HuR knockdown. Furthermore, the expression of cell cycle-related proteins, such as cyclin A, cyclin B1, cyclin D1, and cyclin-dependent kinase 1, was reduced in HuR-knockdown cancer cells, and HuR bound to cdk1 mRNA to stabilize it. These findings suggest that HuR knockdown changes the features of oral cancer cells, at least in part, by affecting their cell cycle and shows potential as an effective therapeutic approach.
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Affiliation(s)
- Wataru Kakuguchi
- Department of Oral Pathology and Biology, Hokkaido University Graduate School of Dental Medicine, Kita-ku, Sapporo, Japan
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Krishnamurthy P, Lambers E, Verma S, Thorne T, Qin G, Losordo DW, Kishore R. Myocardial knockdown of mRNA-stabilizing protein HuR attenuates post-MI inflammatory response and left ventricular dysfunction in IL-10-null mice. FASEB J 2010; 24:2484-94. [PMID: 20219984 DOI: 10.1096/fj.09-149815] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Prolonged inflammatory response is associated with left ventricular (LV) dysfunction and adverse remodeling following myocardial infarction (MI). IL-10 inhibits inflammation by suppressing HuR-mediated mRNA stabilization of proinflammatory cytokines. Here we report that following MI, IL-10(-/-) mice showed exaggerated LV dysfunction, fibrosis, and cardiomyocyte apoptosis. Short-hairpin RNA (shRNA)-mediated knockdown of HuR in the myocardium significantly reversed MI-induced LV dysfunctions and LV remodeling. HuR knockdown significantly reduced MI-induced cardiomyocyte apoptosis concomitant with reduced p53 expression. Moreover, HuR knockdown significantly reduced infarct size and fibrosis area, which in turn was associated with decreased TGF-beta expression. In vitro, stable knockdown of HuR in mouse macrophage cell line RAW 264.7 corroborated in vivo data and revealed reduced mRNA expression of TNF-alpha, TGF-beta, and p53 following LPS challenge, which was associated with a marked reduction in the mRNA stability of these genes. Taken together, our studies suggest that HuR is a direct target of IL-10, and HuR knockdown mimics anti-inflammatory effects of IL-10.
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Affiliation(s)
- Prasanna Krishnamurthy
- Feinberg Cardiovascular Research Institute, Division of Cardiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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Meisner NC, Filipowicz W. Properties of the regulatory RNA-binding protein HuR and its role in controlling miRNA repression. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 700:106-23. [PMID: 21627034 DOI: 10.1007/978-1-4419-7823-3_10] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Gene expression in eukaryotes is subject to extensive regulation at posttranscriptional levels. One of the most important sites of control involves mRNA 3' untranslated regions (3'UTRs), which are recognized by RNA-binding proteins (RBPs) and microRNAs (miRNAs). These factors greatly influence translational efficiency and stability of target mRNAs and often also determine their cellular localization. HuR, a ubiquitously expressed member of the ELAV family of RBPs, has been implicated in regulation of stability and translation of over one hundred mRNAs in mammalian cells. Recent data indicate that some of the effects of HuR can be explained by its interplay with miRNAs. Binding of HuR may suppress the inhibitory effect of miRNAs interacting with the 3'UTR and redirect the repressed mRNA to polysomes for active translation. However, HuR can also synergize with miRNAs. The finding that HuR is able to disengage miRNAs from the repressed mRNA, or render them inactive, provides evidence that miRNA regulation is much more dynamic then originally anticipated. In this chapter we review properties of HuR and describe examples of the cross-talk between the protein and miRNAs, with emphasis on response of the regulation to cellular stress.
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