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Jodoin R, Carrier JC, Rivard N, Bisaillon M, Perreault JP. G-quadruplex located in the 5'UTR of the BAG-1 mRNA affects both its cap-dependent and cap-independent translation through global secondary structure maintenance. Nucleic Acids Res 2019; 47:10247-10266. [PMID: 31504805 PMCID: PMC6821271 DOI: 10.1093/nar/gkz777] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 08/27/2019] [Accepted: 08/31/2019] [Indexed: 12/19/2022] Open
Abstract
The anti-apoptotic BAG-1 protein isoforms are known to be overexpressed in colorectal tumors and are considered to be potential therapeutic targets. The isoforms are derived from alternative translation initiations occuring at four in-frame start codons of a single mRNA transcript. Its 5′UTR also contains an internal ribosome entry site (IRES) regulating the cap-independent translation of the transcript. An RNA G-quadruplex (rG4) is located at the 5′end of the BAG-1 5′UTR, upstream of the known cis-regulatory elements. Herein, we observed that the expression of BAG-1 isoforms is post-transcriptionally regulated in colorectal cancer cells and tumors, and that stabilisation of the rG4 by small molecules ligands reduces the expression of endogenous BAG-1 isoforms. We demonstrated a critical role for the rG4 in the control of both cap-dependent and independent translation of the BAG-1 mRNA in colorectal cancer cells. Additionally, we found an upstream ORF that also represses BAG-1 mRNA translation. The structural probing of the complete 5′UTR showed that the rG4 acts as a steric block which controls the initiation of translation at each start codon of the transcript and also maintains the global 5′UTR secondary structure required for IRES-dependent translation.
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Affiliation(s)
- Rachel Jodoin
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Julie C Carrier
- Service de Gastro-entérologie, Département de médecine, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Nathalie Rivard
- Département d'Anatomie et de Biologie Cellulaire, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Martin Bisaillon
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Jean-Pierre Perreault
- Département de Biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
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The La protein counteracts cisplatin-induced cell death by stimulating protein synthesis of anti-apoptotic factor Bcl2. Oncotarget 2018; 7:29664-76. [PMID: 27105491 PMCID: PMC5045424 DOI: 10.18632/oncotarget.8819] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/28/2016] [Indexed: 02/06/2023] Open
Abstract
Up-regulation of anti-apoptotic factors is a critical mechanism of cancer cell resistance and often counteracts the success of chemotherapeutic treatment. Herein, we identified the cancer-associated RNA-binding protein La as novel factor contributing to cisplatin resistance. Our data demonstrate that depletion of the RNA-binding protein La in head and neck squamous cell carcinoma cells (HNSCC) increases the sensitivity toward cisplatin-induced cell death paralleled by reduced expression of the anti-apoptotic factor Bcl2. Furthermore, it is shown that transient expression of Bcl2 in La-depleted cells protects against cisplatin-induced cell death. By dissecting the underlying mechanism we report herein, that the La protein is required for Bcl2 protein synthesis in cisplatin-treated cells. The RNA chaperone La binds in close proximity to the authentic translation start site and unwinds a secondary structure embedding the authentic AUG. Altogether, our data support a novel model, whereby cancer-associated La protein contributes to cisplatin resistance by stimulating the translation of anti-apoptotic factor Bcl2 in HNSCC cells.
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Liu S, Ren B, Gao H, Liao S, Zhai YX, Li S, Su XJ, Jin P, Stroncek D, Xu Z, Zeng Q, Li Y. Over-expression of BAG-1 in head and neck squamous cell carcinomas (HNSCC) is associated with cisplatin-resistance. J Transl Med 2017; 15:189. [PMID: 28877725 PMCID: PMC5588726 DOI: 10.1186/s12967-017-1289-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 08/24/2017] [Indexed: 01/31/2023] Open
Abstract
Background In order to improve therapy for head and neck squamous cell carcinoma (HNSCC), biomarkers associated with local and/or distant tumor relapses and cancer drug resistance are urgently needed. This study identified a potential biomarker, Bcl-2 associated athanogene-1 (BAG-1), that is implicated in HNSCC insensitive to cisplatin and tumor progression. Methods Primary and advanced (relapsed from parental) University of Michigan squamous cell carcinoma cell lines were tested for sensitivity to cisplatin and gene expression profiles were compared between primary (cisplatin sensitive) and the relapsed (cisplatin resistant) cell lines by using Agilent microarrays. Additionally, differentially expressed genes phosphorylated AKT, and BAG-1, and BCL-xL were evaluated for expression using HNSCC tissue arrays. Results Advanced HNSCC cells revealed resistant to cisplatin accompanied by increased expression of BAG-1 protein. siRNA knockdown of BAG-1 expression resulted in significant improvement of HNSCC sensitivity to cisplatin. BAG-1 expression enhanced stability of BCL-xL and conferred cisplatin resistant to the HNSCC cells. In addition, high levels of expression of phosphorylated AKT, BAG-1, and BCL-xL were observed in advanced HNSCC compared to in that of primary HNSCC. Conclusion Increased expression of BAG-1 was associated with cisplatin resistance and tumor progression in HNSCC patients and warrants further validation in larger independent studies. Over expression of BAG-1 may be a biomarker for cisplatin resistance in patients with primary or recurrent HNSCCs and targeting BAG-1 could be helpful in overcoming cisplatin resistance. Electronic supplementary material The online version of this article (doi:10.1186/s12967-017-1289-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shutong Liu
- The Key Laboratory of Pathobiology, Ministry of Education, Norman Bethune College of Medicine, Jilin University, Changchun, 130021, Jilin, China.,Cell Processing Section, Department of Transfusion, Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Bo Ren
- The Key Laboratory of Pathobiology, Ministry of Education, Norman Bethune College of Medicine, Jilin University, Changchun, 130021, Jilin, China
| | - Hang Gao
- The Key Laboratory of Pathobiology, Ministry of Education, Norman Bethune College of Medicine, Jilin University, Changchun, 130021, Jilin, China
| | - Suchan Liao
- The Key Laboratory of Pathobiology, Ministry of Education, Norman Bethune College of Medicine, Jilin University, Changchun, 130021, Jilin, China.,Department of Physiology, Youjiang Medical University for Nationalities, Baise, 533000, Guangxi, China
| | - Ying-Xian Zhai
- The Key Laboratory of Pathobiology, Ministry of Education, Norman Bethune College of Medicine, Jilin University, Changchun, 130021, Jilin, China
| | - Shirong Li
- The Key Laboratory of Pathobiology, Ministry of Education, Norman Bethune College of Medicine, Jilin University, Changchun, 130021, Jilin, China
| | - Xue-Jin Su
- The Key Laboratory of Pathobiology, Ministry of Education, Norman Bethune College of Medicine, Jilin University, Changchun, 130021, Jilin, China
| | - Ping Jin
- Cell Processing Section, Department of Transfusion, Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA
| | - David Stroncek
- Cell Processing Section, Department of Transfusion, Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Zhixiang Xu
- The Key Laboratory of Pathobiology, Ministry of Education, Norman Bethune College of Medicine, Jilin University, Changchun, 130021, Jilin, China.,Division of Hematology/Oncology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Qinghua Zeng
- The Key Laboratory of Pathobiology, Ministry of Education, Norman Bethune College of Medicine, Jilin University, Changchun, 130021, Jilin, China. .,Division of Hematology/Oncology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
| | - Yulin Li
- The Key Laboratory of Pathobiology, Ministry of Education, Norman Bethune College of Medicine, Jilin University, Changchun, 130021, Jilin, China.
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Al-Hebshi NN, Li S, Nasher AT, El-Setouhy M, Alsanosi R, Blancato J, Loffredo C. Exome sequencing of oral squamous cell carcinoma in users of Arabian snuff reveals novel candidates for driver genes. Int J Cancer 2016; 139:363-72. [PMID: 26934577 DOI: 10.1002/ijc.30068] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/16/2016] [Indexed: 02/06/2023]
Abstract
The study sought to identify genetic aberrations driving oral squamous cell carcinoma (OSCC) development among users of shammah, an Arabian preparation of smokeless tobacco. Twenty archival OSCC samples, 15 of which with a history of shammah exposure, were whole-exome sequenced at an average depth of 127×. Somatic mutations were identified using a novel, matched controls-independent filtration algorithm. CODEX and Exomedepth coupled with a novel, Database of Genomic Variant-based filter were employed to call somatic gene-copy number variations. Significantly mutated genes were identified with Oncodrive FM and the Youn and Simon's method. Candidate driver genes were nominated based on Gene Set Enrichment Analysis. The observed mutational spectrum was similar to that reported by the TCGA project. In addition to confirming known genes of OSCC (TP53, CDKNA2, CASP8, PIK3CA, HRAS, FAT1, TP63, CCND1 and FADD) the analysis identified several candidate novel driver events including mutations of NOTCH3, CSMD3, CRB1, CLTCL1, OSMR and TRPM2, amplification of the proto-oncogenes FOSL1, RELA, TRAF6, MDM2, FRS2 and BAG1, and deletion of the recently described tumor suppressor SMARCC1. Analysis also revealed significantly altered pathways not previously implicated in OSCC including Oncostatin-M signalling pathway, AP-1 and C-MYB transcription networks and endocytosis. There was a trend for higher number of mutations, amplifications and driver events in samples with history of shammah exposure particularly those that tested EBV positive, suggesting an interaction between tobacco exposure and EBV. The work provides further evidence for the genetic heterogeneity of oral cancer and suggests shammah-associated OSCC is characterized by extensive amplification of oncogenes.
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Affiliation(s)
- Nezar Noor Al-Hebshi
- Department of Preventive Dentistry, College of Dentistry, Jazan University, Jazan, Kingdom of Saudi Arabia
| | - Shiyong Li
- Department of Oncology and Pharmacogenomics, Beijing Genome Institute (BGI), Shenzhen, Republic of China
| | - Akram Thabet Nasher
- Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Sana'a University, Yemen
| | - Maged El-Setouhy
- Substance Abuse Research Center (SARC), Jazan University, Jazan, Kingdom of Saudi Arabia
| | - Rashad Alsanosi
- Substance Abuse Research Center (SARC), Jazan University, Jazan, Kingdom of Saudi Arabia
| | - Jan Blancato
- Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
| | - Christopher Loffredo
- Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
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Huang W, Liu Z, Zhou G, Tian A, Sun N. Magnetic gold nanoparticle-mediated small interference RNA silencing Bag-1 gene for colon cancer therapy. Oncol Rep 2015; 35:978-84. [PMID: 26717967 DOI: 10.3892/or.2015.4453] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 10/19/2015] [Indexed: 11/06/2022] Open
Abstract
Bcl-2-associated athanogene 1 (Bag-1) is a positive regulator of Bcl-2 which is an anti-apoptotic gene. Bag-1 was very slightly expressed in normal tissues, but often highly expressed in many tumor tissues, particularly in colon cancer, which can promote metastasis, poor prognosis and anti-apoptotic function of colon cancer. We prepared and evaluated magnetic gold nanoparticle/Bag-1 siRNA recombinant plasmid complex, a gene therapy system, which can transfect cells efficiently, for both therapeutic effect and safety in vitro mainly by electrophoretic mobility shift assays, flow cytometric analyses, cell viability assays, western blot analyses and RT-PCR (real-time) assays. Magnetic gold nanoparticle/Bag-1 siRNA recombinant plasmid complex was successfully transfected into LoVo colon cancer cells and the exogenous gene was expressed in the cells. Flow cytometric results showed apoptosis rate was significantly increased. In MTT assays, magnetic gold nanoparticles revealed lower cytotoxicity than Lipofectamine 2000 transfection reagents (P<0.05). Both in western blot analyses and RT-PCR assays, magnetic gold nanoparticle/Bag-1 siRNA recombinant plasmid complex transfected cells demonstrated expression of Bag-1 mRNA (P<0.05) and protein (P<0.05) was decreased. In further study, c-myc and β-catenin which are main molecules of Wnt/β‑catenin pathway were decreased when Bag-1 were silenced in nanoparticle plasmid complex transfected LoVo cells. These results suggest that magnetic gold nanoparticle mediated siRNA silencing Bag-1 is an effective gene therapy method for colon cancer.
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Affiliation(s)
- Wenbai Huang
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 200012, P.R. China
| | - Zhan'ao Liu
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 200012, P.R. China
| | - Guanzhou Zhou
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 200012, P.R. China
| | - Ailing Tian
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 200012, P.R. China
| | - Nianfeng Sun
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong 200012, P.R. China
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Mashukova A, Kozhekbaeva Z, Forteza R, Dulam V, Figueroa Y, Warren R, Salas PJ. The BAG-1 isoform BAG-1M regulates keratin-associated Hsp70 chaperoning of aPKC in intestinal cells during activation of inflammatory signaling. J Cell Sci 2014; 127:3568-77. [PMID: 24876225 DOI: 10.1242/jcs.151084] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Atypical PKC (ι/λ and ζ; hereafter referred to as aPKC) is a key player in the acquisition of epithelial polarity and participates in other signaling cascades including the control of NF-κB signaling. This kinase is post-translationally regulated through Hsp70-mediated refolding. Previous work has shown that such a chaperoning activity is specifically localized to keratin intermediate filaments. Our work was performed with the goal of identifying the molecule(s) that block Hsp70 activity on keratin filaments during inflammation. A transcriptional screen allowed us to focus on BAG-1, a multi-functional protein that assists Hsp70 in nucleotide exchange but also blocks its activity at higher concentrations. We found the BAG-1 isoform BAG-1M upregulated threefold in human Caco-2 cells following stimulation with tumor necrosis factor receptor α (TNFα) to induce a pro-inflammatory response, and up to sixfold in mouse enterocytes following treatment with dextran sodium sulfate (DSS) to induce colitis. BAG-1M, but no other isoform, was found to co-purify with intermediate filaments and block Hsp70 activity in the keratin fraction but not in the soluble fraction within the range of concentrations found in epithelial cells cultured under control and inflammation conditions. Constitutive expression of BAG-1M decreased levels of phosphorylated aPKC. By contrast, knockdown of BAG-1, blocked the TNFα-induced decrease of phosphorylated aPKC. We conclude that BAG-1M mediates Hsp70 inhibition downstream of NF-κB.
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Affiliation(s)
- Anastasia Mashukova
- Nova Southeastern University, Department of Physiology, Fort Lauderdale, FL 33314, USA University of Miami Miller School of Medicine, Department of Cell Biology, Miami, FL 33136, USA
| | - Zhanna Kozhekbaeva
- University of Miami Miller School of Medicine, Department of Cell Biology, Miami, FL 33136, USA
| | - Radia Forteza
- University of Miami Miller School of Medicine, Department of Cell Biology, Miami, FL 33136, USA
| | - Vipin Dulam
- University of Miami Miller School of Medicine, Department of Cell Biology, Miami, FL 33136, USA
| | - Yolanda Figueroa
- University of Miami Miller School of Medicine, Department of Cell Biology, Miami, FL 33136, USA
| | - Robert Warren
- University of Miami Miller School of Medicine, Department of Cell Biology, Miami, FL 33136, USA
| | - Pedro J Salas
- University of Miami Miller School of Medicine, Department of Cell Biology, Miami, FL 33136, USA
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7
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Southern SL, Collard TJ, Urban BC, Skeen VR, Smartt HJ, Hague A, Oakley F, Townsend PA, Perkins ND, Paraskeva C, Williams AC. BAG-1 interacts with the p50-p50 homodimeric NF-κB complex: implications for colorectal carcinogenesis. Oncogene 2012; 31:2761-72. [PMID: 21963853 PMCID: PMC3272420 DOI: 10.1038/onc.2011.452] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 07/28/2011] [Accepted: 08/18/2011] [Indexed: 02/06/2023]
Abstract
Understanding the mechanisms that promote aberrant tumour cell survival is critical for the determination of novel strategies to combat colorectal cancer (CRC). We have recently shown that the anti-apoptotic protein BAG-1, highly expressed in pre-malignant and CRC tissue, can potentiate cell survival through regulating NF-κB transcriptional activity. In this study, we identify a novel complex between BAG-1 and the p50-p50 NF-κB homodimers, implicating BAG-1 as a co-regulator of an atypical NF-κB pathway. Importantly, the BAG-1-p50 complex was detected at gene regulatory sequences including the epidermal growth factor receptor (EGFR) and COX-2 (PTGS2) genes. Suppression of BAG-1 expression using small interfering RNA was shown to increase EGFR and suppress COX-2 expression in CRC cells. Furthermore, mouse embryonic fibroblasts derived from the NF-κB1 (p105/p50) knock-out mouse were used to demonstrate that p50 expression was required for BAG-1 to suppress EGFR expression. This was shown to be functionally relevant as attenuation of BAG-1 expression increased ligand activated phosphorylation of EGFR in CRC cells. In summary, this paper identifies a novel role for BAG-1 in modulating gene expression through interaction with the p50-p50 NF-κB complexes. Data presented led us to propose that BAG-1 can act as a selective regulator of p50-p50 NF-κB responsive genes in colorectal tumour cells, potentially important for the promotion of cell survival in the context of the fluctuating tumour microenvironment. As BAG-1 expression is increased in the developing adenoma through to metastatic lesions, understanding the function of the BAG-1-p50 NF-κB complexes may aid in identifying strategies for both the prevention and treatment of CRC.
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Affiliation(s)
- Samantha L. Southern
- University of Bristol, School of Cellular & Molecular Medicine, Medical Sciences Building, University Walk, Bristol BS8 1TD UK
| | - Tracey J. Collard
- University of Bristol, School of Cellular & Molecular Medicine, Medical Sciences Building, University Walk, Bristol BS8 1TD UK
| | - Bettina C Urban
- University of Bristol, School of Cellular & Molecular Medicine, Medical Sciences Building, University Walk, Bristol BS8 1TD UK
| | - Victoria R Skeen
- University of Bristol, School of Cellular & Molecular Medicine, Medical Sciences Building, University Walk, Bristol BS8 1TD UK
| | - Helena J Smartt
- University of Bristol, School of Cellular & Molecular Medicine, Medical Sciences Building, University Walk, Bristol BS8 1TD UK
| | - Angela Hague
- University of Bristol, School of Oral & Dental Sciences, Lower Maudlin Street, Bristol BS1 2LY UK
| | - Fiona Oakley
- Newcastle University Institute for Cell and Molecular Biosciences (ICaMB), Medical School, Catherine Cookson Building, Framlington Place, Newcastle upon Tyne, NE2 4HH UK
| | - Paul A Townsend
- University of Southampton, Cancer Sciences, School of Medicine, Southampton General Hospital, Southampton, SO16 6YDUK
| | - Neil D. Perkins
- Newcastle University Institute for Cell and Molecular Biosciences (ICaMB), Medical School, Catherine Cookson Building, Framlington Place, Newcastle upon Tyne, NE2 4HH UK
| | - Christos Paraskeva
- University of Bristol, School of Cellular & Molecular Medicine, Medical Sciences Building, University Walk, Bristol BS8 1TD UK
| | - Ann C. Williams
- University of Bristol, School of Cellular & Molecular Medicine, Medical Sciences Building, University Walk, Bristol BS8 1TD UK
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Hassumi-Fukasawa MK, Miranda-Camargo FA, Zanetti BR, Galano DF, Ribeiro-Silva A, Soares EG. Expression of BAG-1 and PARP-1 in precursor lesions and invasive cervical cancer associated with human papillomavirus (HPV). Pathol Oncol Res 2012; 18:929-37. [PMID: 22454210 DOI: 10.1007/s12253-012-9523-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 03/08/2012] [Indexed: 11/26/2022]
Abstract
Cervical cancer remains persistently the second most common malignancies among women worldwide, responsible for 500,000 new cases annually. Only in Brazil, the estimate is for 18,430 new cases in 2011. Several types of molecular markers have been studied in carcinogenesis including proteins associated with apoptosis such as BAG-1 and PARP-1. This study aims to demonstrate the expression of BAG-1 and PARP-1 in patients with low-grade squamous intraepithelial lesions (LSILs), high-grade squamous intraepithelial lesions (HSILs) and invasive squamous cell carcinomas (SCCs) of the uterine cervix and to verify a possible association with HPV infection. Fifty samples of LSILs, 50 samples of HSILs and 50 samples of invasive SCCs of the uterine cervix were analyzed by immunohistochemistry for BAG-1 and PARP-1 expression. PCR was performed to detect and type HPV DNA. BAG-1 expression levels were significantly different between LSILs and HSILs (p = 0,014) and between LSILs and SCCs (p = 0,014). In regards to PARP-1 expression, we found significant differences between the expression levels in HSILs and SCCs (p = 0,022). No association was found between BAG-1 expression and the presence of HPV. However, a significant association was found between PARP-1 expression and HPV positivity in the HSILs group (p = 0,021). In conclusion our research suggests that BAG-1 expression could contribute to the differentiation between LSIL and HSIL/SCC whereas PARP-1 could be useful to the differentiation between HSIL HPV-related and SCC. Further studies are needed to clarify the molecular aspects of the relationship between PARP-1 expression and HPV infection, with potential applications for cervical cancer prediction.
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Affiliation(s)
- Marcela Kazue Hassumi-Fukasawa
- Department of Pathology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Avenida dos Bandeirantes, 3900, 14049-900, Ribeirão Preto, São Paulo, Brazil.
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Co-overexpression of Bag-1 and heat shock protein 70 in human epidermal squamous cell carcinoma: Bag-1-mediated resistance to 5-fluorouracil-induced apoptosis. Br J Cancer 2011; 104:1459-71. [PMID: 21522149 PMCID: PMC3101929 DOI: 10.1038/bjc.2011.111] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Background: The aim was to determine whether Bcl-2-associated athanogene-1 (Bag-1) and/or its binding protein heat shock protein-70 (Hsp70) exhibit deregulated expression in epidermal squamous cell carcinoma (SCC) and whether Bag-1 confers apoptosis resistance. Method: Immunohistochemistry for Bag-1 and Hsp70 was performed on 60 epidermal SCC and 10 normal skin samples. The epidermal SCC cell line SCC-13 was treated with 5-fluorouracil (5-FU) after Bag-1 knockdown to determine whether high Bag-1 levels contribute to growth and/or apoptosis resistance. Results: Normal epithelium expressed primarily nuclear Bag-1. Most tumours showed reduced nuclear Bag-1 staining, but a subset exhibited strong Bag-1 staining, with cytoplasmic Bag-1 staining intensity correlating with cytoplasmic Hsp70 staining intensity (rs=0.462; P<0.001) and less differentiation (P<0.001). Bag-1 knockdown resulted in markedly reduced SCC-13 cell yield, increased spontaneous apoptosis and enhanced sensitivity to 5-FU-induced apoptosis. Apoptosis induced by 5-FU in the Bag-1-knockdown cells was significantly greater than the additive apoptotic effect of 5-FU or Bag-1 knockdown alone. Conclusions: Overexpression of Bag-1 and Hsp70 in poorly differentiated SCC may confer both enhanced tumour cell growth and apoptosis resistance. Bag-1 may contribute to the resistance of more advanced epidermal SCC to chemotherapy.
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10
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Zheng HC, Xu XY, Xing YN, Wei ZL, Takahashi H, Masuda S, Takano Y. Nuclear or cytoplasmic localization of Bag-1 distinctly correlates with pathologic behavior and outcome of gastric carcinomas. Hum Pathol 2010; 41:724-36. [PMID: 20096920 DOI: 10.1016/j.humpath.2009.10.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 10/15/2009] [Accepted: 10/22/2009] [Indexed: 01/26/2023]
Abstract
Bag-1 is an antiapoptotic protein with its altered expression and localization in malignancies. To clarify the role of Bag-1 in gastric carcinogenesis, its expression was examined by immunohistochemistry and in situ hybridization on a tissue microarray containing gastric carcinomas, adjacent nonneoplastic mucosa (NNM), adenomas, intestinal metaplasia (IM), or gastritis. Gastric carcinoma tissue and cell lines were studied for Bag-1 expression by Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR). The results demonstrated that Bag-1 proteins were differentially expressed in the nucleus or cytosol of MKN28, AGS, MKN45, KATO-III, or HGC-27 cell lines, despite similar levels of messenger RNA (mRNA) expression. The Bag-1 mRNA overexpression was detectable in 73.3% of 15 gastric carcinomas without significant difference in its encoding products' levels. The nuclear Bag-1 expression gradually decreased from gastritis, IM, adenoma to carcinoma (P < .05), and negatively correlated with lymphatic invasion or lymph node metastasis, cytoplasmic Bag-1 expression, negative parafibromin expression, and poor prognosis (P < .05). Cytoplasmic Bag-1 was weakly immunoreactive in carcinomas, compared with gastritis (P < .05), and positively associated with invasive depth and poor prognosis of the carcinoma (P < .05). The positive rate of Bag-1 mRNA expression was higher in adjacent IMs than carcinomas or adjacent NNM (P < .05). Bag-1 mRNA was expressed more in carcinomas from female patients than the male counterparts (P < .05). There was a positive correlation of Bag-1 mRNA expression with invasive depth and venous invasion (P < .05). Our study indicated that aberrant expression and subcellular distribution of Bag-1 might play an important role in the malignant transformation of gastric epithelial cells and should be considered as a biomarker for gastric carcinogenesis, subsequent progression, and prognosis.
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Affiliation(s)
- Hua-chuan Zheng
- Department of Biochemistry and Molecular Biology, College of Basic Medicine, China Medical University, Shenyang, 110001 China.
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