1
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Zhang Y, Lv X, Chen L, Liu Y. The role and function of CLU in cancer biology and therapy. Clin Exp Med 2023; 23:1375-1391. [PMID: 36098834 DOI: 10.1007/s10238-022-00885-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 08/29/2022] [Indexed: 11/03/2022]
Abstract
Clusterin (CLU) is a highly evolutionary conserved glycoprotein with multiple isoform-specific functions and is widely distributed in different species. Accumulated evidence has shown the prominent role of CLU in regulating several essential physiological processes, including programmed cell death, metastasis, invasion, proliferation and cell growth via regulating diverse signaling pathways to mediate cancer progression in various cancers, such as prostate, breast, lung, liver, colon, bladder and pancreatic cancer. Several studies have revealed the potential benefit of inhibiting CLU in CLU inhibition-based targeted cancer therapies in vitro, in vivo or in human, suggesting CLU is a promising therapeutic target. This review discusses the multiple functions and mechanisms of CLU in regulating tumor progression of various cancers and summarizes the inhibitors of CLU used in CLU inhibition-based targeted cancer therapies.
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Affiliation(s)
- Yefei Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Department of Biochemistry, Institute of Cancer, College of Life Science, Nanjing Normal University, Nanjing, 210023, People's Republic of China
| | - Xiang Lv
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Department of Biochemistry, Institute of Cancer, College of Life Science, Nanjing Normal University, Nanjing, 210023, People's Republic of China
| | - Liming Chen
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Department of Biochemistry, Institute of Cancer, College of Life Science, Nanjing Normal University, Nanjing, 210023, People's Republic of China.
| | - Yan Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Department of Biochemistry, Institute of Cancer, College of Life Science, Nanjing Normal University, Nanjing, 210023, People's Republic of China.
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2
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Fu Y, Du Q, Cui T, Lu Y, Niu G. A pan-cancer analysis reveals role of clusterin ( CLU) in carcinogenesis and prognosis of human tumors. Front Genet 2023; 13:1056184. [PMID: 36685863 PMCID: PMC9846084 DOI: 10.3389/fgene.2022.1056184] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 12/05/2022] [Indexed: 01/06/2023] Open
Abstract
Clusterin (CLU) is a chaperone-like protein that has been demonstrated to have a direct relationship with cancer occurrence, progression, or metastasis. Clusterin was downregulated in tumor tissues using three datasets of tongue squamous carcinoma from the Gene Expression Omnibus. We further retrieved datasets from The Cancer Genome Atlas and Gene Expression Omnibus to thoroughly investigate the carcinogenic consequences of Clusterin. Our findings revealed that decreased Clusterin expression in malignancies was associated with a worse overall survival prognosis in individuals with multiple tumors; Clusterin gene deep deletions were found in almost all malignancies and were connected to most cancer patient's prognosis, Clusterin DNA methylation level was dependent on tumor type, Clusterin expression was also linked to the invasion of cancer-associated CD8+ T-cells and fibroblasts in numerous cancer forms. Moreover, pathway enrichment analysis revealed that Clusterin primarily regulates biological processes such as cholesterol metabolism, phospholipid binding, and protein-lipid complex formation. Overall, our pan-cancer research suggests that Clusterin expression levels are linked to tumor carcinogenesis and prognosis, which contributes to understanding the probable mechanism of Clusterin in tumorigenesis as well as its clinical prognostic significance.
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Affiliation(s)
- Yizhe Fu
- Department of Oral and Maxillofacial Surgery, the First Affiliated Hospital of Nanchang University, Nanchang, China,Department of Stomatology, Beijing Integrated Traditional Chinese and Western Medicine Hospital, Beijing, China
| | - Qiao Du
- Department of Stomatology, Beijing Integrated Traditional Chinese and Western Medicine Hospital, Beijing, China
| | - Tiehan Cui
- Department of Oral and Maxillofacial Surgery, the First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Yuying Lu
- Department of Oral and Maxillofacial Surgery, the First Affiliated Hospital of Nanchang University, Nanchang, China,Department of Stomatology, Beijing Integrated Traditional Chinese and Western Medicine Hospital, Beijing, China
| | - Guangliang Niu
- Department of Oral and Maxillofacial Surgery, the First Affiliated Hospital of Nanchang University, Nanchang, China,Department of Stomatology, Beijing Integrated Traditional Chinese and Western Medicine Hospital, Beijing, China,*Correspondence: Guangliang Niu,
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3
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Matta C, Fellows CR, Quasnichka H, Williams A, Jeremiasse B, Allaway D, Mobasheri A. Clusterin secretion is attenuated by the proinflammatory cytokines interleukin-1β and tumor necrosis factor-α in models of cartilage degradation. J Orthop Res 2021; 39:1017-1029. [PMID: 32725904 DOI: 10.1002/jor.24814] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/17/2020] [Accepted: 07/27/2020] [Indexed: 02/04/2023]
Abstract
The protein clusterin has been implicated in the molecular alterations that occur in articular cartilage during osteoarthritis (OA). Clusterin exists in two isoforms with opposing functions, and their roles in cartilage have not been explored. The secreted form of clusterin (sCLU) is a cytoprotective extracellular chaperone that prevents protein aggregation, enhances cell proliferation and promotes viability, whereas nuclear clusterin acts as a pro-death signal. Therefore, these two clusterin isoforms may be putative molecular markers of repair and catabolic responses in cartilage and the ratio between them may be important. In this study, we focused on sCLU and used established, pathophysiologically relevant, in vitro models to understand its role in cytokine-stimulated cartilage degradation. The secretome of equine cartilage explants, osteochondral biopsies and isolated unpassaged chondrocytes was analyzed by western blotting for released sCLU, cartilage oligomeric protein (COMP) and matrix metalloproteinases (MMP) 3 and 13, following treatment with the proinflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α. Release of sulfated glycosaminoglycans (sGAG) was determined using the dimethylmethylene blue assay. Clusterin messenger RNA (mRNA) expression was quantified by quantitative real-time polymerase chain reaction. MMP-3, MMP-13, COMP, and sGAG release from explants and osteochondral biopsies was elevated with cytokine treatment, confirming cartilage degradation in these models. sCLU release was attenuated with cytokine treatment in all models, potentially limiting its cytoprotective function. Clusterin mRNA expression was down-regulated 7-days post cytokine stimulation. These observations implicate sCLU in catabolic responses of chondrocytes, but further studies are required to evaluate its role in OA and its potential as an investigative biomarker.
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Affiliation(s)
- Csaba Matta
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Department of Veterinary Preclinical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Surrey, UK
| | - Christopher R Fellows
- Department of Veterinary Preclinical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Surrey, UK
| | - Helen Quasnichka
- Department of Veterinary Preclinical Sciences, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Surrey, UK
| | | | - Bernadette Jeremiasse
- Departments of Rheumatology and Clinical Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - David Allaway
- Biomarkers Division, WALTHAM Petcare Science Institute, Waltham-on-the-Wolds, Leicestershire, UK
| | - Ali Mobasheri
- Departments of Rheumatology and Clinical Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands.,Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.,Department of Regenerative Medicine, State Research Institute, Centre for Innovative Medicine, Vilnius, Lithuania.,Department of Orthopedics, University Medical Centre Utrecht, Utrecht, The Netherlands.,Centre for Sport, Exercise and Osteoarthritis Versus Arthritis, Queen's Medical Centre, Nottingham, UK
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4
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Xu L, Tian S, Peng X, Hua Y, Yang W, Chen L, Liu S, Wu W, Zhao J, He J, Wu L, Yang J, Zheng Y. Clusterin inhibits Aβ 42 aggregation through a "strawberry model" as detected by FRET-FCS. J Neurochem 2021; 158:444-454. [PMID: 33694231 DOI: 10.1111/jnc.15344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 02/19/2021] [Accepted: 03/07/2021] [Indexed: 11/28/2022]
Abstract
Extracellular plaque deposits of β-amyloid peptide (Aβ) are one of the main pathological features of Alzheimer's disease (AD). The aggregation of Aβ42 species, especially Aβ42 oligomers, is still an active research field in AD pathogenesis. Secretory clusterin protein (sCLU), an extracellular chaperone, plays an important role in AD pathogenesis. Although sCLU interacts directly with Aβ42 in vitro and in vivo, the mechanism is not clear. In this paper, His-tagged sCLU (sCLU-His) was cloned, expressed and purified, and we applied florescence resonance energy transfer-fluorescence correlation spectroscopy (FRET-FCS) to investigate the direct interaction of sCLU-His and Aβ42 at the single-molecule fluorescence level in vitro. Here, we chose four different fluorescently labeled Aβ42 oligomers to form two different groups of aggregation models, easy or difficult to aggregate. The results showed that sCLU-His could form complexes with both aggregation models, and sCLU-His inhibited the aggregation of Aβ42/RB ~ Aβ42/Atto647 (easy to aggregate model). The complexes were produced as the Aβ42/Label adhered to the sCLU-His, which is similar to a "strawberry model," as strawberry seeds are dotted on the outer surface of strawberries. This work provided additional insight into the interaction mechanism of sCLU and Aβ42 .
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Affiliation(s)
- Lingwan Xu
- School of Sciences, Beijing Jiaotong University, Beijing, China
| | - Shijun Tian
- Hebei Agriculture University, Baoding, China
| | - Xianglei Peng
- School of Sciences, Beijing Jiaotong University, Beijing, China
| | - Ying Hua
- School of Sciences, Beijing Jiaotong University, Beijing, China
| | - Wenxuan Yang
- School of Sciences, Beijing Jiaotong University, Beijing, China
| | - Longwei Chen
- School of Sciences, Beijing Jiaotong University, Beijing, China
| | - Shilei Liu
- School of Sciences, Beijing Jiaotong University, Beijing, China
| | - Wenzheng Wu
- School of Sciences, Beijing Jiaotong University, Beijing, China
| | - Jiang Zhao
- Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Jinsheng He
- School of Sciences, Beijing Jiaotong University, Beijing, China
| | - Liqing Wu
- National Institute of Metrology, Beijing, China
| | - Jingfa Yang
- Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Yanpeng Zheng
- School of Sciences, Beijing Jiaotong University, Beijing, China
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Sun C, Xie G, Huang F, Liu X. Effects of Calcium Oxalate on Expression of Clusterin and Lower Urinary Tract Symptoms in Prostatitis and Benign Prostatic Hyperplasia Patients with Calculi. Med Sci Monit 2018; 24:9196-9203. [PMID: 30560838 PMCID: PMC6320640 DOI: 10.12659/msm.911505] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Background Prostatic calculi are common in urological treatments. Our major purpose in the present study was to explore the occurrence and composition of prostatic calculi, and investigate the effect of calcium oxalate (CaOx) on clusterin expression and lower urinary tract symptom (LUTS) in prostatitis and benign prostatic hyperplasia (BPH) patients with calculi. Material/Methods From December 2016 to January 2017, a total of 79 prostatitis patients aged more than 50 years were enrolled. The patients were divided into 3 groups: group A had small calculi (discrete, small echoes); group B had large calculi (large masses of multiple echoes, much coarser), and group C had no calculi. Immunohistochemical analysis was performed to evaluate the tissue scores. The clusterin expression was detected by quantitative real-time CR (qRT-PCR), Western blot, and immunofluorescence. Results According to multifactor analysis, age was significantly associated with prostatic calculus. The composition of prostatic calculus was an independent factor of LUTS. The clusterin expression was elevated in group B. The mRNA and protein levels of clusterin in prostatitis and BPH patients with stones were obviously higher than those in prostatitis and BPH patients without stones. CaOx enhanced clusterin expression in a dose-dependent manner. Conclusions Large prostatic calculi were associated with LUST. Furthermore, CaOx enhanced clusterin expression, leading to large prostatic calculi. These results may provide a therapeutic strategy for prostatitis and BPH.
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Affiliation(s)
- Chengliang Sun
- Department of Urology, Wuhan Asia General Hospital, Wuhan, Hubei, China (mainland)
| | - Guocui Xie
- Department of Urology, Tongren Hospital of Wuhan University (Wuhan Third Hospital), Wuhan, Hubei, China (mainland)
| | - Fei Huang
- Department of Rehabilitation, Hubei Provincial Hospital of TCM (Hubei Institute of Traditional Chinese Medicine), Wuhan, Hubei, China (mainland)
| | - Xukun Liu
- Department of Urology, Tongren Hospital of Wuhan University (Wuhan Third Hospital), Wuhan, Hubei, China (mainland)
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Zhang J, Miao C, Xu A, Zhao K, Qin Z, Li X, Liang C, Hua Y, Chen W, Zhang C, Liu Y, Su S, Wang Z, Liu B. Prognostic Role of Secretory Clusterin in Multiple Human Malignant Neoplasms: A Meta-Analysis of 26 Immunohistochemistry Studies. PLoS One 2016; 11:e0161150. [PMID: 27532124 PMCID: PMC4988765 DOI: 10.1371/journal.pone.0161150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/01/2016] [Indexed: 01/11/2023] Open
Abstract
Secretory clusterin (sCLU) is a potential prognostic tumour biomarker, but results of different sCLU studies are inconsistent. We conducted this meta-analysis to evaluate the precise predictive value of sCLU. Qualified studies were identified by performing online searches in PubMed, EMBASE, and Web of Science. The selected articles were divided into three groups based on scoring method for clusterin detection. Pooled hazard ratios (HRs) with 95% confidence interval (CI) for patient survival and disease recurrence were calculated to determine the correlation between sCLU expression and cancer prognosis. Heterogeneity was assessed using I2 statistics, and specific heterogeneity in different groups was analysed. Elevated sCLU was significantly associated with recurrence-free survival in groups 1 and 3 (group 1: pooled HR = 1.35, 95% CI = 1.01 to 1.79; group 3: pooled HR = 1.80, 95% CI = 1.22 to 2.65). However, clusterin expression was not associated with overall survival in all three groups. Results showed that only the heterogeneity of group 2 was very strong (p = 0.013, I2 = 76.3%), in which the specimens were scored through sCLU staining intensity only. sCLU is a potential biomarker for tumour prognosis, and IHC methods can be more standardised if both intensity and staining proportion are considered.
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Affiliation(s)
- Jianzhong Zhang
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
| | - Chenkui Miao
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
| | - Aiming Xu
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
| | - Kai Zhao
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
| | - Zhiqiang Qin
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
| | - Xiao Li
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
| | - Chao Liang
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
| | - Yibo Hua
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
| | - Wei Chen
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
| | - Chao Zhang
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
| | - Yiyang Liu
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
| | - Shifeng Su
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
| | - Zengjun Wang
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
| | - Bianjiang Liu
- State Key Laboratory of Reproductive Medicine and Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing. 210029, China
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Li Y, Liu H, Barta CL, Judge PD, Zhao L, Zhang WJ, Gong S, Beisel KW, He DZZ. Transcription Factors Expressed in Mouse Cochlear Inner and Outer Hair Cells. PLoS One 2016; 11:e0151291. [PMID: 26974322 PMCID: PMC4790917 DOI: 10.1371/journal.pone.0151291] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 02/25/2016] [Indexed: 11/24/2022] Open
Abstract
Regulation of gene expression is essential to determining the functional complexity and morphological diversity seen among different cells. Transcriptional regulation is a crucial step in gene expression regulation because the genetic information is directly read from DNA by sequence-specific transcription factors (TFs). Although several mouse TF databases created from genome sequences and transcriptomes are available, a cell type-specific TF database from any normal cell populations is still lacking. We identify cell type-specific TF genes expressed in cochlear inner hair cells (IHCs) and outer hair cells (OHCs) using hair cell-specific transcriptomes from adult mice. IHCs and OHCs are the two types of sensory receptor cells in the mammalian cochlea. We show that 1,563 and 1,616 TF genes are respectively expressed in IHCs and OHCs among 2,230 putative mouse TF genes. While 1,536 are commonly expressed in both populations, 73 genes are differentially expressed (with at least a twofold difference) in IHCs and 13 are differentially expressed in OHCs. Our datasets represent the first cell type-specific TF databases for two populations of sensory receptor cells and are key informational resources for understanding the molecular mechanism underlying the biological properties and phenotypical differences of these cells.
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Affiliation(s)
- Yi Li
- Department of Otorhinolaryngology—Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, 68178, United States of America
| | - Huizhan Liu
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, 68178, United States of America
| | - Cody L. Barta
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, 68178, United States of America
| | - Paul D. Judge
- Department of Otorhinolaryngology—Head and Neck Surgery, University of Nebraska Medical Center, Omaha, NE, 68198, United States of America
| | - Lidong Zhao
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, 68178, United States of America
- Department of Otorhinolaryngology—Head and Neck Surgery, Chinese PLA General Hospital, Beijing, 100853, China
| | - Weiping J. Zhang
- Department of Pathophysiology, Second Military Medical University, Shanghai, 200433, China
| | - Shusheng Gong
- Department of Otorhinolaryngology—Head and Neck Surgery, Beijing Friendship Hospital, Beijing, China
| | - Kirk W. Beisel
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, 68178, United States of America
| | - David Z. Z. He
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, 68178, United States of America
- * E-mail:
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Vanhooren V, Navarrete Santos A, Voutetakis K, Petropoulos I, Libert C, Simm A, Gonos ES, Friguet B. Protein modification and maintenance systems as biomarkers of ageing. Mech Ageing Dev 2015; 151:71-84. [DOI: 10.1016/j.mad.2015.03.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/24/2015] [Accepted: 03/26/2015] [Indexed: 12/22/2022]
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Bonacini M, Coletta M, Ramazzina I, Naponelli V, Modernelli A, Davalli P, Bettuzzi S, Rizzi F. Distinct promoters, subjected to epigenetic regulation, drive the expression of two clusterin mRNAs in prostate cancer cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:44-54. [PMID: 25464035 DOI: 10.1016/j.bbagrm.2014.11.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 10/24/2014] [Accepted: 11/03/2014] [Indexed: 01/13/2023]
Abstract
The human clusterin (CLU) gene codes for several mRNAs characterized by different sequences at their 5' end. We investigated the expression of two CLU mRNAs, called CLU 1 and CLU 2, in immortalized (PNT1a) and tumorigenic (PC3 and DU145) prostate epithelial cells, as well as in normal fetal fibroblasts (WI38) following the administration of the epigenetic drugs 5-aza-2'-deoxycytidine (AZDC) and trichostatin A (TSA) given either as single or combined treatment (AZDC-TSA). Our experimental evidences show that: a) CLU 1 is the most abundant transcript variant. b) CLU 2 is expressed at a low level in normal fibroblasts and virtually absent in prostate cancer cells. c) CLU 1, and to a greater extent CLU 2 expression, increased by AZDC-TSA treatment in prostate cancer cells. d) Both CLU 1 and CLU 2 encode for secreted CLU. e) P2, a novel promoter that overlaps the CLU 2 Transcription Start Site (TSS), drives CLU 2 expression. f) A CpG island, methylated in prostate cancer cells and not in normal fibroblasts, is responsible for long-term heritable regulation of CLU 1 expression. g) ChIP assay of histone tail modifications at CLU promoters (P1 and P2) shows that treatment of prostate cancer cells with AZDC-TSA causes enrichment of Histone3(Lys9)acetylated (H3K9ac) and reduction of Histone3(Lys27)trimethylated (H3K27me3), inducing active transcription of both CLU variants. In conclusion, we show for the first time that the expression of CLU 2 mRNA is driven by a novel promoter, P2, whose activity responds to epigenetic drugs treatment through changes in histone modifications.
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Affiliation(s)
- Martina Bonacini
- Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy
| | - Mariangela Coletta
- Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy
| | - Ileana Ramazzina
- Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy; Centre for Molecular and Translational Oncology (COMT), University of Parma, Parco Area delle Scienze 11/a, 43124 Parma, Italy; National Institute of Biostructure and Biosystems (INBB), Viale Medaglie d'Oro 305, 00136 Rome, Italy
| | - Valeria Naponelli
- Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy; Centre for Molecular and Translational Oncology (COMT), University of Parma, Parco Area delle Scienze 11/a, 43124 Parma, Italy; National Institute of Biostructure and Biosystems (INBB), Viale Medaglie d'Oro 305, 00136 Rome, Italy
| | - Alice Modernelli
- Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy
| | - Pierpaola Davalli
- Department of Biomedical Sciences, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy
| | - Saverio Bettuzzi
- Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy; Centre for Molecular and Translational Oncology (COMT), University of Parma, Parco Area delle Scienze 11/a, 43124 Parma, Italy; National Institute of Biostructure and Biosystems (INBB), Viale Medaglie d'Oro 305, 00136 Rome, Italy.
| | - Federica Rizzi
- Department of Biomedicine, Biotechnology and Translational Research, University of Parma, Via Volturno 39/a, 43126 Parma, Italy; Centre for Molecular and Translational Oncology (COMT), University of Parma, Parco Area delle Scienze 11/a, 43124 Parma, Italy; National Institute of Biostructure and Biosystems (INBB), Viale Medaglie d'Oro 305, 00136 Rome, Italy
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Intracellular clusterin interacts with brain isoforms of the bridging integrator 1 and with the microtubule-associated protein Tau in Alzheimer's disease. PLoS One 2014; 9:e103187. [PMID: 25051234 PMCID: PMC4106906 DOI: 10.1371/journal.pone.0103187] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/26/2014] [Indexed: 12/11/2022] Open
Abstract
Sporadic or late-onset Alzheimer's disease (AD) is expected to affect 50% of individuals reaching 85 years of age. The most significant genetic risk factor for late-onset AD is the e4 allele of APOE gene encoding apolipoprotein E, a lipid carrier shown to modulate brain amyloid burden. Recent genome-wide association studies have uncovered additional single nucleotide polymorphisms (SNPs) linked to AD susceptibility, including those in the CLU and BIN1 genes encoding for clusterin (CLU) and the bridging integrator 1 (BIN1) proteins, respectively. Because CLU has been implicated in brain amyloid-β (Aβ) clearance in mouse models of amyloid deposition, we sought to investigate whether an AD-linked SNP in the CLU gene altered Aβ42 biomarker levels in the cerebrospinal fluid (CSF). Instead, we found that the CLU rs11136000 SNP modified CSF levels of the microtubule-associated protein Tau in AD patients. We also found that an intracellular form of CLU (iCLU) was upregulated in the brain of Tau overexpressing Tg4510 mice, but not in Tg2576 amyloid mouse model. By overexpressing iCLU and Tau in cell culture systems we discovered that iCLU was a Tau-interacting protein and that iCLU associated with brain-specific isoforms of BIN1, also recently identified as a Tau-binding protein. Through expression analysis of CLU and BIN1 variants, we found that CLU and BIN1 interacted via their coiled-coil motifs. In co-immunoprecipitation studies using human brain tissue, we showed that iCLU and the major BIN1 isoform expressed in neurons were associated with modified Tau species found in AD. Finally, we showed that expression of certain coding CLU variants linked to AD risk led to increased levels of iCLU. Together, our findings suggest that iCLU and BIN1 interaction might impact Tau function in neurons and uncover potential new mechanisms underlying the etiology of Tau pathology in AD.
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Nguan CYC, Guan Q, Gleave ME, Du C. Promotion of cell proliferation by clusterin in the renal tissue repair phase after ischemia-reperfusion injury. Am J Physiol Renal Physiol 2014; 306:F724-33. [DOI: 10.1152/ajprenal.00410.2013] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Renal repair begins soon after the kidney suffers ischemia-reperfusion injury (IRI); however, its molecular pathways are not fully understood. Clusterin (Clu) is a chaperone protein with cytoprotective functions in renal IRI. The aim of this study was to investigate the role of Clu in renal repair after IRI. IRI was induced in the left kidneys of wild-type (WT) C57BL/6J (B6) vs. Clu knockout (KO) B6 mice by clamping the renal pedicles for 28–45 min at the body temperature of 32°C. The renal repair was assessed by histology and confirmed by renal function. Gene expression was examined using PCR array. Here, we show that following IRI, renal tubular damage and Clu expression in WT kidneys were induced at day 1, reached the maximum at day 3, and significantly diminished at day 7 along with normal function, whereas the tubular damage in Clu KO kidneys steadily increased from initiation of insult to the end of the experiment, when renal failure occurred. Renal repair in WT kidneys was positively correlated with an increase in Ki67+ proliferative tubular cells and survival from IRI. The functions of Clu in renal repair and renal tubular cell proliferation in cultures were associated with upregulation of a panel of genes that could positively regulate cell cycle progression and DNA damage repair, which might promote cell proliferation but not involve cell migration. In conclusion, these data suggest that Clu is required for renal tissue regeneration in the kidney repair phase after IRI, which is associated with promotion of tubular cell proliferation.
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Affiliation(s)
- Christopher Y. C. Nguan
- Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Qiunong Guan
- Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Martin E. Gleave
- Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada
- Vancouver Prostate Centre, Vancouver, British Columbia, Canada; and
| | - Caigan Du
- Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada
- Immunity and Infection Research Centre, Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada
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Time-Dependent Decrease of Clusterin as a Potential Cerebrospinal Fluid Biomarker for Drug-Resistant Epilepsy. J Mol Neurosci 2014; 54:1-9. [DOI: 10.1007/s12031-014-0237-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Accepted: 01/13/2014] [Indexed: 10/25/2022]
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13
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Non-secreted clusterin isoforms are translated in rare amounts from distinct human mRNA variants and do not affect Bax-mediated apoptosis or the NF-κB signaling pathway. PLoS One 2013; 8:e75303. [PMID: 24073260 PMCID: PMC3779157 DOI: 10.1371/journal.pone.0075303] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 08/14/2013] [Indexed: 01/08/2023] Open
Abstract
Clusterin, also known as apolipoprotein J, is expressed from a variety of tissues and implicated in pathological disorders such as neurodegenerative diseases, ischemia and cancer. In contrast to secretory clusterin (sCLU), which acts as an extracellular chaperone, the synthesis, subcellular localization and function(s) of intracellular CLU isoforms is currently a matter of intense discussion. By investigating human CLU mRNAs we here unravel mechanisms leading to the synthesis of distinct CLU protein isoforms and analyze their subcellular localization and their impact on apoptosis and on NF-κB-activity. Quantitative PCR-analyses revealed the expression of four different stress-inducible CLU mRNA variants in non-cancer and cancer cell lines. In all cell lines variant 1 represents the most abundant mRNA, whereas all other variants collectively account for no more than 0.34% of total CLU mRNA, even under stressed conditions. Overexpression of CLU cDNAs combined with in vitro mutagenesis revealed distinct translational start sites including a so far uncharacterized non-canonical CUG start codon. We show that all exon 2-containing mRNAs encode sCLU and at least three non-glycosylated intracellular isoforms, CLU1‑449, CLU21‑449 and CLU34‑449, which all reside in the cytosol of unstressed and stressed HEK‑293 cells. The latter is the only form expressed from an alternatively spliced mRNA variant lacking exon 2. Functional analysis revealed that none of these cytosolic CLU forms modulate caspase-mediated intrinsic apoptosis or significantly affects TNF-α-induced NF-κB-activity. Therefore our data challenge some of the current ideas regarding the physiological functions of CLU isoforms in pathologies.
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Nestheide S, Bridge JA, Barnes M, Frayer R, Sumegi J. Pharmacologic inhibition of epigenetic modification reveals targets of aberrant promoter methylation in Ewing sarcoma. Pediatr Blood Cancer 2013; 60:1437-46. [PMID: 23508900 DOI: 10.1002/pbc.24526] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 02/07/2013] [Indexed: 12/18/2022]
Abstract
BACKGROUND Ewing sarcoma (ES), a highly aggressive tumor of children and young adults, is characterized most commonly by an 11;22 chromosomal translocation that fuses EWSR1 located at 22q12 with FLI1, coding for a member of the ETS family of transcription factors. Although genetic changes in ES have been extensively researched, our understanding of the role of epigenetic modifications in this neoplasm is limited. PROCEDURE In an effort to improve our knowledge in the role of epigenetic changes in ES we evaluated the in vitro antineoplastic effect of the DNA methyltransferase inhibitor 5-Aza-deoxycytidine (5-Aza-dC) and identified epigenetically silenced genes by pharmacologic unmasking of DNA methylation coupled with genome-wide expression profiling. RESULTS Comparisons between untreated and 5-Aza-dC treated ES cell lines (n = 5) identified 208 probe sets with at least twofold difference in expression (P ≤ 0.05). The 208 probe sets represented 145 upregulated and 31 down-regulated genes. Of the 145 genes upregulated after 5-Aza-dC treatment, four: were further characterized. ACRC, CLU, MEST, and NNAT were found to be hypermethylated and transcriptionally down-regulated in ES cell lines. Further studies revealed that ACRC, CLU, MEST, and NNAT were often hypermethylated in primary ES tumors. Transfection-mediated reexpression of ACRC, CLU, MEST, and NNAT in ES cell lines resulted in decreased growth in culture. CONCLUSIONS This study demonstrated epigenetically modified genes in ES cell lines and primary tumors and suggested that epigenetic dysregulation may contribute to disease pathogenesis in ES.
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Affiliation(s)
- Shawnagay Nestheide
- Faculty of Medicine, Division of Bone Marrow Transplantation and Immune Deficiency, Blood and Cancer Research Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, USA
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15
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Charnay Y, Imhof A, Vallet PG, Kovari E, Bouras C, Giannakopoulos P. Clusterin in neurological disorders: Molecular perspectives and clinical relevance. Brain Res Bull 2012; 88:434-43. [DOI: 10.1016/j.brainresbull.2012.05.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 05/07/2012] [Indexed: 10/28/2022]
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16
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Han Z, Wang Z, Cheng G, Liu B, Li P, Li J, Wang W, Yin C, Zhang W. Presence, localization, and origin of clusterin in normal human spermatozoa. J Assist Reprod Genet 2012; 29:751-7. [PMID: 22552734 DOI: 10.1007/s10815-012-9779-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Accepted: 04/18/2012] [Indexed: 12/29/2022] Open
Abstract
PURPOSE Clusterin in mammalian semen is a secretory form of clusterin (sCLU) with the heterodimeric structure. It is secreted by the epididymis and seminal vesicle. It is generally agreed that clusterin mainly exists on the surface of abnormal spermatozoa and is implicated in decreased sperm motility, sperm aggregation and infertility. However, few studies observe clusterin in normal spermatozoa, which is presumed to be a novel form. Up to now, the systematical information about the presence, localization, origin and function of clusterin in normal human spermatozoa has yet not been established. The aim of our current study is to systematically research clusterin in normal human spermatozoa. METHODS We detected the presence of clusterin via western blot, explored the localization of clusterin using immunofluorescence, and investigated the origin and distribution of clusterin in human testis by western blot and immunohistochemistry. RESULTS We found native clusterin in the inner plasma membrane of normal human spermatozoa. It was derived from the testis and showed similar molecular weight and heterodimeric structure compared with sCLU in semen and on the surface of abnormal spermatozoa. CONCLUSION Clusterin in normal spermatozoa should be self-synthesized during the later stage of spermatogenesis. The different localization and origin suggested that the clusterin observed by us may be a novel form compared with conventional sCLU on the surface of abnormal spermatozoa.
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Affiliation(s)
- Zhijian Han
- Department of Urology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
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Xue J, Lv DD, Jiao S, Zhao W, Li X, Sun H, Yan B, Fan L, Hu RG, Fang J. pVHL mediates K63-linked ubiquitination of nCLU. PLoS One 2012; 7:e35848. [PMID: 22532874 PMCID: PMC3332038 DOI: 10.1371/journal.pone.0035848] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 03/23/2012] [Indexed: 11/19/2022] Open
Abstract
pVHL, product of von Hippel-Lindau (VHL) tumor suppressor gene, functions as the substrate recognition component of an E3-ubiquitin ligase that targets proteins for ubiquitination and proteasomal degradation. Hypoxia-inducible factor α (HIFα) is the well-known substrate of pVHL. Besides HIFα, pVHL also binds to many other proteins and has multiple functions. In this manuscript, we report that the nuclear clusterin (nCLU) is a target of pVHL. We found that pVHL had a direct interaction with nCLU. nCLU bound to pVHL at pVHL's β domain, the site for recognition of substrate, indicating that nCLU might be a substrate of pVHL. Interestingly, pVHL bound to nCLU but did not lead to nCLU destruction. Further studies indicated that pVHL mediated K63-linked ubiquitination of nCLU and promoted nCLU nuclear translocation. In summary, our results disclose a novel function of pVHL that mediates K63-linked ubiquitination and identify nCLU as a new target of pVHL.
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Affiliation(s)
- Jing Xue
- The Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, SIBS, Chinese Academy of Sciences, Shanghai, China
| | - Dan-dan Lv
- The Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, SIBS, Chinese Academy of Sciences, Shanghai, China
| | - Shi Jiao
- The Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, SIBS, Chinese Academy of Sciences, Shanghai, China
| | - Wenting Zhao
- The Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, SIBS, Chinese Academy of Sciences, Shanghai, China
| | - Xuebing Li
- The Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, SIBS, Chinese Academy of Sciences, Shanghai, China
| | - Heng Sun
- The Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, SIBS, Chinese Academy of Sciences, Shanghai, China
| | - Bing Yan
- The Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, SIBS, Chinese Academy of Sciences, Shanghai, China
| | - Li Fan
- The Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, SIBS, Chinese Academy of Sciences, Shanghai, China
| | - Rong-gui Hu
- The Institute of Biochemistry and Cell Biology, SIBS, Chinese Academy of Sciences, Shanghai, China
| | - Jing Fang
- The Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, SIBS, Chinese Academy of Sciences, Shanghai, China
- * E-mail:
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Abstract
Clusterin, also known as apolipoprotein J, is a ubiquitous multifunctional glycoprotein. Following its identification in 1983, clusterin was found to be clearly increased in Alzheimer's disease (AD). Later research demonstrated that clusterin could bind amyloid-beta (Abeta) peptides and prevent fibril formation, a hallmark of AD pathology. In addition to preventing excessive inflammation, intracellular clusterin was found to reduce apoptosis and oxidative stress. Although early studies were inconclusive, two recent large-scale genome-wide association studies (GWAS) independently identified variants within the clusterin gene as risk factors for developing AD. This review focuses on the characteristics of clusterin and possible mechanisms of its relationship to AD.
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Affiliation(s)
- Zhong-Chen Wu
- Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, Shandong Province, China
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19
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Filfil R, Paul-Roc B, Cantin C, Iqbal U, Tolkatchev D, Vinogradova A, Xu P, Ni F, O'Connor-McCourt MD, Lenferink AE. Molecular imaging of breast tumors using a near-infrared fluorescently labeled clusterin binding peptide. Int J Cancer 2012; 131:E681-92. [DOI: 10.1002/ijc.27368] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 10/31/2011] [Indexed: 12/31/2022]
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Hassan MK, Watari H, Christenson L, Bettuzzi S, Sakuragi N. Intracellular clusterin negatively regulates ovarian chemoresistance: compromised expression sensitizes ovarian cancer cells to paclitaxel. Tumour Biol 2011; 32:1031-47. [PMID: 21761117 DOI: 10.1007/s13277-011-0207-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 06/29/2011] [Indexed: 12/20/2022] Open
Abstract
Understanding the molecular events that lead to paclitaxel (TX) resistance is necessary to identify effective means to prevent chemoresistance. Previously, results from our lab revealed that secretory clusterin (CLU) form positively mediates TX response in ovarian cancer cells. Thus, we had interest to study the role of another non-secreted form (intracellular clusterin (i-CLU)) in chemo-response. Here, we provide evidences that i-CLU form localizes mainly in the nucleus and differentially expressed in the TX-responsive KF cells, versus TX-resistant, KF-TX, ovarian cancer cells and negatively regulate cellular chemo-response. I-CLU was cloned, by deleting the secretion-leading signaling peptide from full-length CLU cDNA, and transiently over-expressed in OVK-18 cells. Forced expression of truncated i-CLU was mainly detectable in the nuclei and significantly reduced cellular growth, accumulating cells in G1 phase which finally died through apoptosis. Importantly, compromised expression of i-CLU under an inducible promoter was tolerated and did not induce apoptosis but sensitized ovarian cancer cells to TX. We then demonstrated that this sensitization mechanism was cell cycle independent and relied on i-CLU/Ku70 binding probably due to controlling the free amount of Ku70 available for DNA repair in the nucleus. Results from CLU immunohistochemistry in ovarian tumor tissues verified the retardation of nuclear CLU staining in the recurrent tumor even though their primary counterparts showed nuclear CLU staining. Thus, the controversial data on CLU function in chemo-response/resistance may be explained by a shift in the pattern of CLU expression and intracellular localization as well when tumor acquires chemoresistance.
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Affiliation(s)
- Mohamed Kamel Hassan
- Department of Gynecology and Obstetrics, Graduate School of Medicine, Hokkaido University, Nishi Ku, Kita-15, Nishi-7, 060-8638, Sapporo, Japan.
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De Flora S, Micale RT, La Maestra S, Izzotti A, D’Agostini F, Camoirano A, Davoli SA, Troglio MG, Rizzi F, Davalli P, Bettuzzi S. Upregulation of Clusterin in Prostate and DNA Damage in Spermatozoa from Bisphenol A–Treated Rats and Formation of DNA Adducts in Cultured Human Prostatic Cells. Toxicol Sci 2011; 122:45-51. [DOI: 10.1093/toxsci/kfr096] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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22
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Song ZM, Sun YL, Mao YS, Liu F, Zhou LP, Zhao XH. Clinical significance of clusterin expression in esophageal squamous cell carcinoma. Shijie Huaren Xiaohua Zazhi 2010; 18:1217-1221. [DOI: 10.11569/wcjd.v18.i12.1217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the expression of clusterin mRNA in esophageal squamous cell carcinoma (ESCC), measure preoperative and postoperative serum clusterin protein levels in ESCC patients, and evaluate their correlations with clinicopathological parameters in ESCC.
METHODS: The expression of full-length clusterin mRNA in ESCC tissue was detected by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Serum clusterin level was measured by enzyme-linked immunosorbent assay (ELISA).
RESULTS: The expression of clusterin mRNA was significantly down-regulated in ESCC tissue compared with matched tumor-adjacent non-cancerous tissue. The median level of serum clusterin in postoperative ESCC patients was significantly higher than that in preoperative patients (25.71 mg/L vs 3.23 mg/L, P < 0.0001). The level of serum clusterin is correlated with tumor size, but not with age, gender, tumor differentiation, tumor grade, lymph node metastasis and biochemical parameters.
CONCLUSION: The expression of clusterin mRNA is down-regulated in ESCC. Serum clusterin level decreases in ESCC patients. Clusterin might be a potential tumor suppressor gene in ESCC. Dynamic measurement of serum clusterin level might aid to evaluate the progression of ESCC.
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