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Qi Y, Li L, Wei Y, Ma F. PP2A as a potential therapeutic target for breast cancer: Current insights and future perspectives. Biomed Pharmacother 2024; 173:116398. [PMID: 38458011 DOI: 10.1016/j.biopha.2024.116398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 02/28/2024] [Accepted: 03/06/2024] [Indexed: 03/10/2024] Open
Abstract
Breast cancer has become the most prevalent malignancy worldwide; however, therapeutic efficacy is far from satisfactory. To alleviate the burden of this disease, it is imperative to discover novel mechanisms and treatment strategies. Protein phosphatase 2 A (PP2A) comprises a family of mammalian serine/threonine phosphatases that regulate many cellular processes. PP2A is dysregulated in several human diseases, including oncological pathologies, and plays a pivotal role in the initiation and progression of tumours. The role of PP2A as a tumour suppressor has been extensively studied, and its regulation can serve as a target for anticancer therapy. Recent studies have shown that PP2A is a tumour promotor. PP2A-mediated anticancer therapy may involve two opposing mechanisms: activation and inhibition. In general, the contradictory roles of PP2A should not be overlooked, and more work is needed to determine the molecular mechanism by which PP2A affects in tumours. In this review, the literature on the role of PP2A in tumours, especially in breast cancer, was analysed. This review describes relevant targets of breast cancer, such as cell cycle control, DNA damage responses, epidermal growth factor receptor, immune modulation and cell death resistance, which may lead to effective therapeutic strategies or influence drug development in breast cancer.
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Affiliation(s)
- Yalong Qi
- Department of Medical Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Chaoyang District, Pan jia yuan nan Road 17, Beijing 100021, China
| | - Lixi Li
- Department of Medical Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Chaoyang District, Pan jia yuan nan Road 17, Beijing 100021, China
| | - Yuhan Wei
- Department of Medical Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Chaoyang District, Pan jia yuan nan Road 17, Beijing 100021, China
| | - Fei Ma
- Department of Medical Oncology, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Chaoyang District, Pan jia yuan nan Road 17, Beijing 100021, China.
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2
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Johnson H, Narayan S, Sharma AK. Altering phosphorylation in cancer through PP2A modifiers. Cancer Cell Int 2024; 24:11. [PMID: 38184584 PMCID: PMC10770906 DOI: 10.1186/s12935-023-03193-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Accepted: 12/25/2023] [Indexed: 01/08/2024] Open
Abstract
Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase integral to the regulation of many cellular processes. Due to the deregulation of PP2A in cancer, many of these processes are turned toward promoting tumor progression. Considerable research has been undertaken to discover molecules capable of modulating PP2A activity in cancer. Because PP2A is capable of immense substrate specificity across many cellular processes, the therapeutic targeting of PP2A in cancer can be completed through either enzyme inhibitors or activators. PP2A modulators likewise tend to be effective in drug-resistant cancers and work synergistically with other known cancer therapeutics. In this review, we will discuss the patterns of PP2A deregulation in cancer, and its known downstream signaling pathways important for cancer regulation, along with many activators and inhibitors of PP2A known to inhibit cancer progression.
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Affiliation(s)
- Hannah Johnson
- Department of Pharmacology, Penn State Cancer Institute, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Satya Narayan
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL, 32610, USA
| | - Arun K Sharma
- Department of Pharmacology, Penn State Cancer Institute, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA.
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3
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Casillas-Espinosa PM, Anderson A, Harutyunyan A, Li C, Lee J, Braine EL, Brady RD, Sun M, Huang C, Barlow CK, Shah AD, Schittenhelm RB, Mychasiuk R, Jones NC, Shultz SR, O'Brien TJ. Disease-modifying effects of sodium selenate in a model of drug-resistant, temporal lobe epilepsy. eLife 2023; 12:e78877. [PMID: 36892461 PMCID: PMC10208637 DOI: 10.7554/elife.78877] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 03/08/2023] [Indexed: 03/10/2023] Open
Abstract
There are no pharmacological disease-modifying treatments with an enduring effect to mitigate the seizures and comorbidities of established chronic temporal lobe epilepsy (TLE). This study aimed to evaluate for disease modifying effects of sodium selenate treatment in the chronically epileptic rat post-status epilepticus (SE) model of drug-resistant TLE. Wistar rats underwent kainic acid-induced SE or sham. Ten-weeks post-SE, animals received sodium selenate, levetiracetam, or vehicle subcutaneousinfusion continuously for 4 weeks. To evaluate the effects of the treatments, one week of continuous video-EEG was acquired before, during, and 4, 8 weeks post-treatment, followed by behavioral tests. Targeted and untargeted proteomics and metabolomics were performed on post-mortem brain tissue to identify potential pathways associated with modified disease outcomes. Telomere length was investigated as a novel surrogate marker of epilepsy disease severity in our current study. The results showed that sodium selenate treatment was associated with mitigation of measures of disease severity at 8 weeks post-treatment cessation; reducing the number of spontaneous seizures (p< 0.05), cognitive dysfunction (p< 0.05), and sensorimotor deficits (p< 0.01). Moreover, selenate treatment was associated with increased protein phosphatase 2A (PP2A) expression, reduced hyperphosphorylated tau, and reversed telomere length shortening (p< 0.05). Network medicine integration of multi-omics/pre-clinical outcomes identified protein-metabolite modules positively correlated with TLE. Our results provide evidence that treatment with sodium selenate results in a sustained disease-modifying effect in chronically epileptic rats in the post-KA SE model of TLE, including improved comorbid learning and memory deficits.
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Affiliation(s)
- Pablo M Casillas-Espinosa
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
- Monash Proteomics & Metabolomics Facility and Monash Biomedicine Discovery Institute, Monash UniversityClayton, VictoriaAustralia
| | - Alison Anderson
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Anna Harutyunyan
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Crystal Li
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Jiyoon Lee
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
| | - Emma L Braine
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Rhys D Brady
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Mujun Sun
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Cheng Huang
- Department of Neurology, The Alfred Hospital, Commercial Road,Melbourne, VictoriaAustralia
| | - Christopher K Barlow
- Department of Neurology, The Alfred Hospital, Commercial Road,Melbourne, VictoriaAustralia
| | - Anup D Shah
- Department of Neurology, The Alfred Hospital, Commercial Road,Melbourne, VictoriaAustralia
| | - Ralf B Schittenhelm
- Department of Neurology, The Alfred Hospital, Commercial Road,Melbourne, VictoriaAustralia
| | - Richelle Mychasiuk
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Nigel C Jones
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Sandy R Shultz
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
| | - Terence J O'Brien
- Department of Medicine, The Royal Melbourne Hospital, The University of MelbourneMelbourneAustralia
- Department of Neuroscience, Central Clinical School, Monash UniversityMelbourneAustralia
- Monash Proteomics & Metabolomics Facility and Monash Biomedicine Discovery Institute, Monash UniversityClayton, VictoriaAustralia
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4
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Yankova R, Tankov I, Mihov D, Kostadinova A. Coordination metal effect on the nonlinear optical properties and biological activity of double selenates. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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5
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Kashani E, Vassella E. Pleiotropy of PP2A Phosphatases in Cancer with a Focus on Glioblastoma IDH Wildtype. Cancers (Basel) 2022; 14:5227. [PMID: 36358647 PMCID: PMC9654311 DOI: 10.3390/cancers14215227] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/13/2022] [Accepted: 10/20/2022] [Indexed: 07/29/2023] Open
Abstract
Serine/Threonine protein phosphatase 2A (PP2A) is a heterotrimeric (or occasionally, heterodimeric) phosphatase with pleiotropic functions and ubiquitous expression. Despite the fact that they all contribute to protein dephosphorylation, multiple PP2A complexes exist which differ considerably by their subcellular localization and their substrate specificity, suggesting diverse PP2A functions. PP2A complex formation is tightly regulated by means of gene expression regulation by transcription factors, microRNAs, and post-translational modifications. Furthermore, a constant competition between PP2A regulatory subunits is taking place dynamically and depending on the spatiotemporal circumstance; many of the integral subunits can outcompete the rest, subjecting them to proteolysis. PP2A modulation is especially important in the context of brain tumors due to its ability to modulate distinct glioma-promoting signal transduction pathways, such as PI3K/Akt, Wnt, Ras, NF-κb, etc. Furthermore, PP2A is also implicated in DNA repair and survival pathways that are activated upon treatment of glioma cells with chemo-radiation. Depending on the cancer cell type, preclinical studies have shown some promise in utilising PP2A activator or PP2A inhibitors to overcome therapy resistance. This review has a special focus on "glioblastoma, IDH wild-type" (GBM) tumors, for which the therapy options have limited efficacy, and tumor relapse is inevitable.
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Affiliation(s)
- Elham Kashani
- Institute of Pathology, University of Bern, 3008 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Erik Vassella
- Institute of Pathology, University of Bern, 3008 Bern, Switzerland
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6
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Vivash L, Malpas CB, Hovens CM, Brodtmann A, Collins S, Macfarlane S, Velakoulis D, O'Brien TJ. Sodium selenate as a disease-modifying treatment for mild-moderate Alzheimer's disease: an open-label extension study. BMJ Neurol Open 2022; 3:e000223. [PMID: 34988458 PMCID: PMC8679123 DOI: 10.1136/bmjno-2021-000223] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/22/2021] [Indexed: 11/04/2022] Open
Abstract
Introduction Sodium selenate is a potential disease-modifying treatment for Alzheimer's disease (AD) which reduces hyperphosphorylated tau through activation of the protein phosphatase 2A enzyme. We have shown sodium selenate to be safe and well tolerated in a 24-week, phase 2a double-blind placebo-controlled randomised controlled trial (RCT), also reporting sodium selenate reduced neurodegeneration on diffusion-weighted MRI. This study assessed the safety and tolerability of chronic sodium selenate treatment (up to 23 months) in patients with AD who had been enrolled in the RCT. Cognitive measures served as secondary outcomes of potential disease-modification. Methods An open-label extension study of sodium selenate (10 mg three times a day) in patients with AD who had completed the previous RCT. Twenty-eight patients were enrolled. Patients were regularly monitored for safety, adverse events (AEs) and protocol compliance. Cognitive tests were administered for measures of disease progression. Results Sixteen patients were discontinued by the sponsor, and 12 discontinued for other reasons. Treatment duration ranged from 6 to 23 months. The majority of AEs were mild (83%), and 33% were treatment-related. Common treatment-related AEs were alopecia (21%) and nail disorder (32%), which both resolved either prior to or following cessation of treatment. Two serious AEs occurred, which were not treatment-related. Alzheimer's Disease Assessment Scale-Cognitive Subscale 11 score increased 1.8 points over 12 months. Discussion Chronic sodium selenate treatment is safe and well tolerated in patients with AD. Cognitive measures suggest a slowing of disease progression though this could not be confirmed as the study was not controlled. Further research into sodium selenate as a treatment for AD is warranted.
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Affiliation(s)
- Lucy Vivash
- Department of Neuroscience, Monash University, Melbourne, Victoria, Australia.,Department of Medicine and Radiology, University of Melbourne, Melbourne, Victoria, Australia.,Department of Neurology, Royal Melbourne Hospital, Parkville, Victoria, Australia.,Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
| | - Charles B Malpas
- Department of Neuroscience, Monash University, Melbourne, Victoria, Australia.,Department of Neurology, Royal Melbourne Hospital, Parkville, Victoria, Australia.,Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia.,Melbourne School of Psychological Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | | | - Amy Brodtmann
- Department of Neurology, Royal Melbourne Hospital, Parkville, Victoria, Australia.,Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia.,Eastern Cognitive Disorders Clinic, Monash University, Melbourne, Victoria, Australia
| | - Steven Collins
- Department of Medicine and Radiology, University of Melbourne, Melbourne, Victoria, Australia
| | | | - Dennis Velakoulis
- Neuropsychiatry Unit, Royal Melbourne Hospital, Melbourne, Victoria, Australia.,Melbourne Neuropsychiatry Centre, University of Melbourne, Melbourne, Victoria, Australia
| | - Terence J O'Brien
- Department of Neuroscience, Monash University, Melbourne, Victoria, Australia.,Department of Medicine and Radiology, University of Melbourne, Melbourne, Victoria, Australia.,Department of Neurology, Royal Melbourne Hospital, Parkville, Victoria, Australia.,Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
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7
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Vivash L, Bertram KL, Malpas CB, Marotta C, Harding IH, Kolbe S, Fielding J, Clough M, Lewis SJG, Tisch S, Evans AH, O'Sullivan JD, Kimber T, Darby D, Churilov L, Law M, Hovens CM, Velakoulis D, O'Brien TJ. Sodium selenate as a disease-modifying treatment for progressive supranuclear palsy: protocol for a phase 2, randomised, double-blind, placebo-controlled trial. BMJ Open 2021; 11:e055019. [PMID: 34916328 PMCID: PMC8679117 DOI: 10.1136/bmjopen-2021-055019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
INTRODUCTION Progressive supranuclear palsy (PSP) is a neurodegenerative disorder for which there are currently no disease-modifying therapies. The neuropathology of PSP is associated with the accumulation of hyperphosphorylated tau in the brain. We have previously shown that protein phosphatase 2 activity in the brain is upregulated by sodium selenate, which enhances dephosphorylation. Therefore, the objective of this study is to evaluate the efficacy and safety of sodium selenate as a disease-modifying therapy for PSP. METHODS AND ANALYSIS This will be a multi-site, phase 2b, double-blind, placebo-controlled trial of sodium selenate. 70 patients will be recruited at six Australian academic hospitals and research institutes. Following the confirmation of eligibility at screening, participants will be randomised (1:1) to receive 52 weeks of active treatment (sodium selenate; 15 mg three times a day) or matching placebo. Regular safety and efficacy visits will be completed throughout the study period. The primary study outcome is change in an MRI volume composite (frontal lobe+midbrain-3rd ventricle) over the treatment period. Analysis will be with a general linear model (GLM) with the MRI composite at 52 weeks as the dependent variable, treatment group as an independent variable and baseline MRI composite as a covariate. Secondary outcomes are change in PSP rating scale, clinical global impression of change (clinician) and change in midbrain mean diffusivity. These outcomes will also be analysed with a GLM as above, with the corresponding baseline measure entered as a covariate. Secondary safety and tolerability outcomes are frequency of serious adverse events, frequency of down-titration occurrences and frequency of study discontinuation. Additional, as yet unplanned, exploratory outcomes will include analyses of other imaging, cognitive and biospecimen measures. ETHICS AND DISSEMINATION The study was approved by the Alfred Health Ethics Committee (594/20). Each participant or their legally authorised representative and their study partner will provide written informed consent at trial commencement. The results of the study will be presented at national and international conferences and published in peer-reviewed journals. TRIAL REGISTRATION NUMBER Australian New Zealand Clinical Trials Registry (ACTRN12620001254987).
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Affiliation(s)
- Lucy Vivash
- Department of Neurosciences, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Health, Melbourne, Victoria, Australia
- Department of Neurology, Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
- Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - Kelly L Bertram
- Department of Neurosciences, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Health, Melbourne, Victoria, Australia
| | - Charles B Malpas
- Department of Neurosciences, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Health, Melbourne, Victoria, Australia
- Melbourne School of Psychological Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Cassandra Marotta
- Department of Neurosciences, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Health, Melbourne, Victoria, Australia
| | - Ian H Harding
- Department of Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Scott Kolbe
- Department of Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Joanne Fielding
- Department of Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Meaghan Clough
- Department of Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Simon J G Lewis
- ForeFront Parkinson's Disease Research Clinic, Brain and Mind Centre, University of Sydney, Sydney, New South Wales, Australia
| | - Stephen Tisch
- Department of Neurology, St Vincent's Hospital Sydney, Darlinghurst, New South Wales, Australia
| | - Andrew H Evans
- Department of Neurology, Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
| | - John D O'Sullivan
- Centre for Clinical Research, University of Queensland, Brisbane, Queensland, Australia
- Department of Neurology, Royal Brisbane & Women's Hospital, Brisbane, Queensland, Australia
| | - Thomas Kimber
- Department of Neurology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - David Darby
- Department of Neurosciences, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Health, Melbourne, Victoria, Australia
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia
- Eastern Cognitive Disorders Clinic, Box Hill Hospital, Melbourne, Victoria, Australia
| | - Leonid Churilov
- Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - Meng Law
- Department of Neurosciences, Monash University, Melbourne, Victoria, Australia
- Department of Radiology, Alfred Hospital, Melbourne, Victoria, Australia
| | - Christopher M Hovens
- Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
| | - Dennis Velakoulis
- Department of Neuropsychiatry, Royal Melbourne Hospital, Parkville, Victoria, Australia
- Melbourne Neuropsychiatry Centre, University of Melbourne, Parkville, Victoria, Australia
| | - Terence J O'Brien
- Department of Neurosciences, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Health, Melbourne, Victoria, Australia
- Department of Neurology, Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
- Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
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8
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Vivash L, Malpas CB, Churilov L, Walterfang M, Brodtmann A, Piguet O, Ahmed RM, Bush AI, Hovens CM, Kalincik T, Darby D, Velakoulis D, O'Brien TJ. A study protocol for a phase II randomised, double-blind, placebo-controlled trial of sodium selenate as a disease-modifying treatment for behavioural variant frontotemporal dementia. BMJ Open 2020; 10:e040100. [PMID: 33199422 PMCID: PMC7670941 DOI: 10.1136/bmjopen-2020-040100] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
INTRODUCTION Behavioural variant frontotemporal dementia (bvFTD) is a neurodegenerative disorder often neuropathologically associated with the accumulation of abnormally hyperphosphorylated tau, for which there is currently no disease-modifying treatment. Previous work by our group has shown sodium selenate upregulates the activity of protein phosphatase 2 in the brain, increasing the rate of tau dephosphorylation. The objective of this study is to evaluate the efficacy and safety of sodium selenate as a disease-modifying treatment for bvFTD. METHODS AND ANALYSIS This will be a multisite, phase IIb, double-blind placebo-controlled trial of sodium selenate. One hundred and twenty participants will be enrolled across 4 Australian academic hospitals. Following screening eligible participants will be randomised (1:1) to sodium selenate (15 mg three times a day) or placebo for 52 weeks. Participants will have regular safety and efficacy visits throughout the study period. The primary study outcome will be percentage brain volume change (PBVC) as measured on MRI over 52 weeks of treatment. This will be analysed with a general linear model (analysis of covariance (ANCOVA)) with the PBVC as an output, the treatment as an input and the baseline brain volume as covariate for adjustment purposes. Secondary outcomes include safety and tolerability measures, and efficacy measures; change in cerebrospinal fluid total-tau, Addenbrooke's Cognitive Examination-III and Cambridge Behavioural Inventory-Revised scores over the 52 weeks of treatment. These will also be analysed with ANCOVA where the corresponding baseline measure will be incorporated in the model. Additional exploratory outcomes will include other imaging, cognitive and biospecimen analyses. ETHICS AND DISSEMINATION The study was approved by the Human Research and Ethics Committee of the lead site as part of the Australian Multisite Ethics approval system. The results of the study will be presented at national and international conferences and published in peer-reviewed journals. TRIAL REGISTRATION NUMBER ACTRN12620000236998 .
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Affiliation(s)
- Lucy Vivash
- Department of Neuroscience, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
- Department of Neurology, Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
- Departments of Medicine and Radiology, University of Melbourne, Parkville, Victoria, Australia
| | - Charles B Malpas
- Department of Neuroscience, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
- Department of Neurology, Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
- CORe, Department of Medicine, University of Melbourne, Parkville, VIC, Australia
| | - Leonid Churilov
- Departments of Medicine and Radiology, University of Melbourne, Parkville, Victoria, Australia
| | - Mark Walterfang
- Department of Neuropsychiatry, Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Melbourne Neuropsychiatry Centre, University of Melbourne, Parkville, Victoria, Australia
| | - Amy Brodtmann
- Department of Neurology, Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
- Florey Institute for Neuroscience and Mental Health, Melbourne, Victoria, Australia
- Eastern Cognitive Disorders Clinic, Monash University, Box Hill, Victoria, Australia
- Melbourne Dementia Research Centre, University of Melbourne, Parkville, VIC, Australia
| | - Olivier Piguet
- School of Psychology, The University of Sydney, Sydney, New South Wales, Australia
- Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Rebekah M Ahmed
- Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia
- Memory and Cognition Clinic, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - Ashley I Bush
- Florey Institute for Neuroscience and Mental Health, Melbourne, Victoria, Australia
- Melbourne Dementia Research Centre, University of Melbourne, Parkville, VIC, Australia
| | - Christopher M Hovens
- Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
| | - T Kalincik
- Department of Neurology, Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
- CORe, Department of Medicine, University of Melbourne, Parkville, VIC, Australia
| | - David Darby
- Department of Neuroscience, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
- Department of Neurology, Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
- Departments of Medicine and Radiology, University of Melbourne, Parkville, Victoria, Australia
- Eastern Cognitive Disorders Clinic, Monash University, Box Hill, Victoria, Australia
| | - Dennis Velakoulis
- Department of Neuropsychiatry, Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Melbourne Neuropsychiatry Centre, University of Melbourne, Parkville, Victoria, Australia
| | - Terence J O'Brien
- Department of Neuroscience, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
- Department of Neurology, Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
- Departments of Medicine and Radiology, University of Melbourne, Parkville, Victoria, Australia
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9
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Ahmed T, Van der Jeugd A, Caillierez R, Buée L, Blum D, D'Hooge R, Balschun D. Chronic Sodium Selenate Treatment Restores Deficits in Cognition and Synaptic Plasticity in a Murine Model of Tauopathy. Front Mol Neurosci 2020; 13:570223. [PMID: 33132838 PMCID: PMC7578417 DOI: 10.3389/fnmol.2020.570223] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 08/26/2020] [Indexed: 12/18/2022] Open
Abstract
A major goal in diseases is identifying a potential therapeutic agent that is cost-effective and can remedy some, if not all, disease symptoms. In Alzheimer’s disease (AD), aggregation of hyperphosphorylated tau protein is one of the neuropathological hallmarks, and Tau pathology correlates better with cognitive impairments in AD patients than amyloid-β load, supporting a key role of tau-related mechanisms. Selenium is a non-metallic trace element that is incorporated in the brain into selenoproteins. Chronic treatment with sodium selenate, a non-toxic selenium compound, was recently reported to rescue behavioral phenotypes in tau mouse models. Here, we focused on the effects of chronic selenate application on synaptic transmission and synaptic plasticity in THY-Tau22 mice, a transgenic animal model of tauopathies. Three months with a supplement of sodium selenate in the drinking water (12 μg/ml) restored not only impaired neurocognitive functions but also rescued long-term depression (LTD), a major form of synaptic plasticity. Furthermore, selenate reduced the inactive demethylated catalytic subunit of protein phosphatase 2A (PP2A) in THY-Tau22 without affecting total PP2A.Our study provides evidence that chronic dietary selenate rescues functional synaptic deficits of tauopathy and identifies activation of PP2A as the putative mechanism.
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Affiliation(s)
- Tariq Ahmed
- Brain and Cognition, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium.,Leuven Brain Institute, Leuven, Belgium
| | - Ann Van der Jeugd
- Leuven Brain Institute, Leuven, Belgium.,Laboratory of Biological Psychology, Brain and Cognition, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium
| | - Raphaëlle Caillierez
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience and Cognition, Lille, France.,Alzheimer and Tauopathies, LabEx DISTALZ, Lille, France
| | - Luc Buée
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience and Cognition, Lille, France.,Alzheimer and Tauopathies, LabEx DISTALZ, Lille, France
| | - David Blum
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience and Cognition, Lille, France.,Alzheimer and Tauopathies, LabEx DISTALZ, Lille, France
| | - Rudi D'Hooge
- Leuven Brain Institute, Leuven, Belgium.,Laboratory of Biological Psychology, Brain and Cognition, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium
| | - Detlef Balschun
- Brain and Cognition, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium.,Leuven Brain Institute, Leuven, Belgium
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10
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Casillas‐Espinosa PM, Ali I, O'Brien TJ. Neurodegenerative pathways as targets for acquired epilepsy therapy development. Epilepsia Open 2020; 5:138-154. [PMID: 32524040 PMCID: PMC7278567 DOI: 10.1002/epi4.12386] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 02/13/2020] [Accepted: 02/24/2020] [Indexed: 12/16/2022] Open
Abstract
There is a growing body of clinical and experimental evidence that neurodegenerative diseases and epileptogenesis after an acquired brain insult may share common etiological mechanisms. Acquired epilepsy commonly develops as a comorbid condition in patients with neurodegenerative diseases such as Alzheimer's disease, although it is likely much under diagnosed in practice. Progressive neurodegeneration has also been described after traumatic brain injury, stroke, and other forms of brain insults. Moreover, recent evidence has shown that acquired epilepsy is often a progressive disorder that is associated with the development of drug resistance, cognitive decline, and worsening of other neuropsychiatric comorbidities. Therefore, new pharmacological therapies that target neurobiological pathways that underpin neurodegenerative diseases have potential to have both an anti-epileptogenic and disease-modifying effect on the seizures in patients with acquired epilepsy, and also mitigate the progressive neurocognitive and neuropsychiatric comorbidities. Here, we review the neurodegenerative pathways that are plausible targets for the development of novel therapies that could prevent the development or modify the progression of acquired epilepsy, and the supporting published experimental and clinical evidence.
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Affiliation(s)
- Pablo M. Casillas‐Espinosa
- Departments of Neuroscience and MedicineCentral Clinical SchoolMonash UniversityMelbourneVic.Australia
- Department of MedicineThe Royal Melbourne HospitalThe University of MelbourneMelbourneVic.Australia
| | - Idrish Ali
- Departments of Neuroscience and MedicineCentral Clinical SchoolMonash UniversityMelbourneVic.Australia
- Department of MedicineThe Royal Melbourne HospitalThe University of MelbourneMelbourneVic.Australia
| | - Terence J. O'Brien
- Departments of Neuroscience and MedicineCentral Clinical SchoolMonash UniversityMelbourneVic.Australia
- Department of MedicineThe Royal Melbourne HospitalThe University of MelbourneMelbourneVic.Australia
- Department of NeurologyThe Alfred HospitalMelbourneVic.Australia
- Department of NeurologyThe Royal Melbourne HospitalParkvilleVic.Australia
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11
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Knox SJ, Jayachandran P, Keeling CA, Stevens KJ, Sandhu N, Stamps-DeAnda SL, Savic R, Shura L, Buyyounouski MK, Grimes K. Results from a Phase 1 Study of Sodium Selenite in Combination with Palliative Radiation Therapy in Patients with Metastatic Cancer. Transl Oncol 2019; 12:1525-1531. [PMID: 31454725 PMCID: PMC6717060 DOI: 10.1016/j.tranon.2019.08.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/02/2019] [Accepted: 08/05/2019] [Indexed: 11/26/2022] Open
Abstract
In preclinical studies, selenite had single agent activity and radiosensitized tumors in vivo. Here we report results from a Phase 1 trial in 15 patients with metastatic cancer treated with selenite (5.5 to 49.5 mg) orally as a single dose 2 hours before each radiation therapy (RT) treatment. Patients received RT regimens that were standard of care. The primary objective of the study was to assess the safety of this combination therapy. Secondary objectives included measurement of pharmacokinetics (PK) and evaluation of efficacy. Endpoints included assessment of PK, toxicity, tumor response, and pain before and after treatment. The half-life of selenite was 18.5 hours. There were no adverse events attributable to selenite until the 33 mg dose level, at which the primary toxicities were grade 1 GI side effects. One patient treated with 49.5 mg had grade 2 GI toxicity. Although this was not a DLT, it was felt that the highest acceptable dose in this patient population was 33 mg. Most patients had stabilization of disease within the RT fields, with some demonstrating objective evidence of tumor regression. Most patients had a marked improvement in pain and seven out of nine patients with prostate cancer had a decrease in PSA ranging from 11-78%. Doses up to 33 mg selenite were well tolerated in combination with RT. A randomized, well controlled study is needed at the 33 mg dose level to determine if selenite results in clinically meaningful improvements in the response to palliative RT.
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Affiliation(s)
- Susan J Knox
- Department of Radiation Oncology, Stanford University, Stanford, CA.
| | - Priya Jayachandran
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
| | | | - Kathryn J Stevens
- Departments of Diagnostic Radiology, Stanford University, Stanford, CA
| | - Navjot Sandhu
- Department of Radiation Oncology, Stanford University, Stanford, CA
| | | | - Rada Savic
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
| | - Lei Shura
- Department of Radiation Oncology, Stanford University, Stanford, CA
| | | | - Kevin Grimes
- Chemical and Systems Biology, Stanford University, Stanford, CA
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12
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Evans SO, Jacobson GM, Goodman HJB, Bird S, Jameson MB. Comparative Safety and Pharmacokinetic Evaluation of Three Oral Selenium Compounds in Cancer Patients. Biol Trace Elem Res 2019; 189:395-404. [PMID: 30187284 DOI: 10.1007/s12011-018-1501-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/30/2018] [Indexed: 02/07/2023]
Abstract
Selenium (Se) compounds have demonstrated anticancer properties in both preclinical and clinical studies, with particular promise in combination therapy where the optimal form and dose of selenium has yet to be established. In a phase I randomised double-blinded study, the safety, tolerability and pharmacokinetic (PK) profiles of sodium selenite (SS), Se-methylselenocysteine (MSC) and seleno-l-methionine (SLM) were compared in patients with chronic lymphocytic leukaemia and a cohort of patients with solid malignancies. Twenty-four patients received 400 μg of elemental Se as either SS, MSC or SLM for 8 weeks. None of the Se compounds were associated with any significant toxicities, and the total plasma Se AUC of SLM was markedly raised in comparison to MSC and SS. DNA damage assessment revealed negligible genotoxicity, and some minor reductions in lymphocyte counts were observed. At the dose level used, all three Se compounds are well-tolerated and non-genotoxic. Further analyses of the pharmacodynamic effects of Se on healthy and malignant peripheral blood mononuclear cells will inform the future evaluation of higher doses of these Se compounds. The study is registered under the Australian and New Zealand Clinical Trials Registry No: ACTRN12613000118707.
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Affiliation(s)
- Stephen O Evans
- Department of Biological Sciences, University of Waikato, Hamilton, New Zealand
- Waikato Clinical Campus, University of Auckland, Hamilton, New Zealand
| | - Gregory M Jacobson
- Department of Biological Sciences, University of Waikato, Hamilton, New Zealand
| | - Hugh J B Goodman
- Regional Cancer Centre, Waikato Hospital, Private Bag 3200, Hamilton, 3240, New Zealand
| | - Steve Bird
- Department of Biological Sciences, University of Waikato, Hamilton, New Zealand
| | - Michael B Jameson
- Waikato Clinical Campus, University of Auckland, Hamilton, New Zealand.
- Regional Cancer Centre, Waikato Hospital, Private Bag 3200, Hamilton, 3240, New Zealand.
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13
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Saletti PG, Ali I, Casillas-Espinosa PM, Semple BD, Lisgaras CP, Moshé SL, Galanopoulou AS. In search of antiepileptogenic treatments for post-traumatic epilepsy. Neurobiol Dis 2019; 123:86-99. [PMID: 29936231 PMCID: PMC6309524 DOI: 10.1016/j.nbd.2018.06.017] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 06/20/2018] [Indexed: 11/28/2022] Open
Abstract
Post-traumatic epilepsy (PTE) is diagnosed in 20% of individuals with acquired epilepsy, and can impact significantly the quality of life due to the seizures and other functional or cognitive and behavioral outcomes of the traumatic brain injury (TBI) and PTE. There is no available antiepileptogenic or disease modifying treatment for PTE. Animal models of TBI and PTE have been developed, offering useful insights on the value of inflammatory, neurodegenerative pathways, hemorrhages and iron accumulation, calcium channels and other target pathways that could be used for treatment development. Most of the existing preclinical studies test efficacy towards pathologies of functional recovery after TBI, while a few studies are emerging testing the effects towards induced or spontaneous seizures. Here we review the existing preclinical trials testing new candidate treatments for TBI sequelae and PTE, and discuss future directions for efforts aiming at developing antiepileptogenic and disease-modifying treatments.
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Affiliation(s)
- Patricia G Saletti
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Idrish Ali
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Australia
| | - Pablo M Casillas-Espinosa
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Australia
| | - Bridgette D Semple
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Australia
| | - Christos Panagiotis Lisgaras
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Solomon L Moshé
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, NY, USA; Dominick P. Purpura Department of Neuroscience, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Einstein/Montefiore Epilepsy Center, Montefiore Medical Center, Bronx, NY, USA; Department of Pediatrics, Albert Einstein College of Medicine, Einstein/Montefiore Epilepsy Center, Montefiore Medical Center, Bronx, NY, USA
| | - Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, NY, USA; Dominick P. Purpura Department of Neuroscience, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Einstein/Montefiore Epilepsy Center, Montefiore Medical Center, Bronx, NY, USA.
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14
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The Anti-Tumor Agent Sodium Selenate Decreases Methylated PP2A, Increases GSK3βY216 Phosphorylation, Including Tau Disease Epitopes and Reduces Neuronal Excitability in SHSY-5Y Neurons. Int J Mol Sci 2019; 20:ijms20040844. [PMID: 30781361 PMCID: PMC6412488 DOI: 10.3390/ijms20040844] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 02/12/2019] [Accepted: 02/12/2019] [Indexed: 12/20/2022] Open
Abstract
Selenium application as sodium selenate was repeatedly shown to have anti-carcinogenic properties by increasing levels of the serine/ threonine protein phosphatase 2A (PP2A) in cancer cells. PP2A has a prominent role in cell development, homeostasis, and in neurons regulates excitability. PP2A, GSK3β and Tau reside together in a complex, which facilitates their interaction and (dys)-function as has been reported for several neurological disorders. In this study we recorded maximum increase in total PP2A at 3 µM sodium selenate in a neuron cell line. In conjunction with these data, whole-cell electrophysiological studies revealed that this concentration had maximum effect on membrane potentials, conductance and currents. Somewhat surprisingly, the catalytically active form, methylated PP2A (mePP2A) was significantly decreased. In close correlation to these data, the phosphorylation state of two substrate proteins, sensitive to PP2A activity, GSK3β and Tau were found to be increased. In summary, our data reveal that sodium selenate enhances PP2A levels, but reduces catalytic activity of PP2A in a dose dependent manner, which fails to reduce Tau and GSK3β phosphorylation under physiological conditions, indicating an alternative route in the rescue of cell pathology in neurological disorders.
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15
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Collery P. Strategies for the development of selenium-based anticancer drugs. J Trace Elem Med Biol 2018; 50:498-507. [PMID: 29548612 DOI: 10.1016/j.jtemb.2018.02.024] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 02/20/2018] [Accepted: 02/26/2018] [Indexed: 02/07/2023]
Abstract
Many experimental models demonstrated that inorganic and organic selenium (Se) compounds may have an anticancer activity. However, large clinical studies failed to demonstrate that Se supplementations may prevent the outcome of cancers. Moreover, there are few randomized trials in cancer patients and there is not yet any Se compound recognized as anticancer drug. There is still a need to develop new Se compounds with new strategies. For that, it may be necessary to consider that Se compounds may have a dual role, either as anti-oxidant or as pro-oxidant. Experimental studies demonstrated that it is as pro-oxidant that Se compounds have anticancer effects, even though cancer cells have a pro-oxidant status. The oxidative status differs according to the type of cancer, the stage of the disease and to other parameters. We propose to adapt the doses of the Se compounds to markers of the oxidative stress, but also to markers of angiogenesis, which is strongly related with the oxidative status. A dual role of Se on angiogenesis has also been noted, either as pro-angiogenesis or as anti-angiogenesis. The objective for the development of new Se compounds, having a great selectivity on cancer cells, could be to try to normalize these oxidative and angiogenic markers in cancer patients, with an individual adaptation of doses.
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Affiliation(s)
- Philippe Collery
- Society for the Coordination of Therapeutic Researches, 20220 Algajola, France.
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16
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Lobb RJ, Jacobson GM, Cursons RT, Jameson MB. The Interaction of Selenium with Chemotherapy and Radiation on Normal and Malignant Human Mononuclear Blood Cells. Int J Mol Sci 2018; 19:ijms19103167. [PMID: 30326581 PMCID: PMC6214079 DOI: 10.3390/ijms19103167] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/02/2018] [Accepted: 10/11/2018] [Indexed: 01/17/2023] Open
Abstract
Selenium, a trace element with anticancer properties, can reduce harmful toxicities of chemotherapy and radiotherapy without compromising efficacy. However, the dose-response relationship in normal versus malignant human cells is unclear. We evaluated how methylseleninic acid (MSA) modulates the toxicity and efficacy of chemotherapy and radiation on malignant and non-malignant human mononuclear blood cells in vitro. We specifically investigated its effects on endoplasmic reticulum stress induction, intracellular glutathione concentration, DNA damage and viability of peripheral blood mononuclear cells and THP1 monocytic leukaemia cells in response to radiation, cytosine arabinoside or doxorubicin chemotherapy. MSA, at lower concentrations, induced protective responses in normal cells but cytotoxic effects in malignant cells, alone and in conjunction with chemotherapy or radiation. However, in normal cells higher concentrations of MSA were directly toxic and increased the cytotoxicity of radiation but not chemotherapy. In malignant cells higher MSA concentrations were generally more effective in combination with cancer treatments. Thus, optimal MSA concentrations differed between normal and malignant cells and treatments. This work supports clinical reports that selenium can significantly reduce dose-limiting toxicities of anticancer therapies and potentially improve efficacy of anticancer treatments. The optimal selenium compound and dose is not yet determined.
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Affiliation(s)
- Richard J Lobb
- Tumour Microenvironment Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia.
| | - Gregory M Jacobson
- Department of Biological Sciences, University of Waikato, Hamilton 3216, New Zealand.
| | - Ray T Cursons
- Department of Biological Sciences, University of Waikato, Hamilton 3216, New Zealand.
| | - Michael B Jameson
- Oncology Department, Waikato Hospital, Hamilton 3204, New Zealand.
- Waikato Clinical Campus, Faculty of Medical and Health Sciences, University of Auckland, Hamilton 3204, New Zealand.
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17
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Ali I, Silva JC, Liu S, Shultz SR, Kwan P, Jones NC, O'Brien TJ. Targeting neurodegeneration to prevent post-traumatic epilepsy. Neurobiol Dis 2018; 123:100-109. [PMID: 30099094 DOI: 10.1016/j.nbd.2018.08.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 07/31/2018] [Accepted: 08/08/2018] [Indexed: 12/14/2022] Open
Abstract
In the quest for developing new therapeutic targets for post-traumatic epilepsies (PTE), identifying mechanisms relevant to development and progression of disease is critical. A growing body of literature suggests involvement of neurodegenerative mechanisms in the pathophysiology of acquired epilepsies, including following traumatic brain injury (TBI). In this review, we discuss the potential of some of these mechanisms to be targets for the development of a therapy against PTE.
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Affiliation(s)
- Idrish Ali
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Australia
| | - Juliana C Silva
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Australia
| | - Shijie Liu
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Australia
| | - Sandy R Shultz
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Australia
| | - Patrick Kwan
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Australia
| | - Nigel C Jones
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Australia
| | - Terence J O'Brien
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Australia.
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18
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Song M, Kumaran MN, Gounder M, Gibbon DG, Nieves-Neira W, Vaidya A, Hellmann M, Kane MP, Buckley B, Shih W, Caffrey PB, Frenkel GD, Rodriguez-Rodriguez L. Phase I trial of selenium plus chemotherapy in gynecologic cancers. Gynecol Oncol 2018; 150:478-486. [PMID: 30068487 DOI: 10.1016/j.ygyno.2018.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/27/2018] [Accepted: 07/01/2018] [Indexed: 10/28/2022]
Abstract
PURPOSE Preclinical studies performed in our laboratory have shown that high-dose selenium inhibits the development of carboplatin drug resistance in an ovarian cancer mouse xenograft model. Based on these data, as well as the potential serious toxicities of supranutritional doses of selenium, a phase I trial of a combination of selenium/carboplatin/paclitaxel was designed to determine the maximum tolerated dose, safety, and effects of selenium on carboplatin pharmacokinetics in the treatment of chemo-naive women with gynecologic cancers. Correlative studies were performed to identify gene targets of selenium. METHODS Chemo-naïve patients with gynecologic malignancy received selenious acid IV on day 1 followed by carboplatin IV and paclitaxel IV on day 3. A standard 3 + 3 dose-escalating design was used for addition of selenium to standard dose chemotherapy. Concentrations of selenium in plasma and carboplatin in plasma ultrafiltrate were analyzed. RESULTS Forty-five patients were enrolled and 291 treatment cycles were administered. Selenium was administered as selenious acid to 9 cohorts of patients with selenium doses ranging from 50 μg to 5000 μg. Grade 3/4 toxicities included neutropenia (66.7%), febrile neutropenia (2.2%), pain (20.0%), infection (13.3%), neurologic (11.1%), and pulmonary adverse effects (11.1%). The maximum tolerated dose of selenium was not reached. Selenium had no effect on carboplatin pharmacokinetics. Correlative studies showed post-treatment downregulation of RAD51AP1, a protein involved in DNA repair, in both cancer cell lines and patient tumors. CONCLUSION Overall, the addition of selenium to carboplatin/paclitaxel chemotherapy is safe and well tolerated, and does not alter carboplatin pharmacokinetics. A 5000 μg dose of elemental selenium as selenious acid is suggested as the dose to be evaluated in a phase II trial.
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Affiliation(s)
- Mihae Song
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, United States
| | - Muthu N Kumaran
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, United States
| | - Murugesan Gounder
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, United States
| | - Darlene G Gibbon
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, United States
| | - Wilberto Nieves-Neira
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, United States
| | - Ami Vaidya
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, United States
| | - Mira Hellmann
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, United States
| | - Michael P Kane
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, United States
| | - Brian Buckley
- Rutgers Environmental and Occupational Health Sciences Institute, 170 Frelinghuysen Road, Piscataway, NJ 08854, United States
| | - Weichung Shih
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, United States
| | - Paula B Caffrey
- Department of Biological Sciences, Rutgers University, 195 University Avenue, Newark, NJ 07102, United States; Department of Biological and Environmental Sciences, 250 University Avenue, California University of PA, California, PA 15419, United States
| | - Gerald D Frenkel
- Department of Biological Sciences, Rutgers University, 195 University Avenue, Newark, NJ 07102, United States
| | - Lorna Rodriguez-Rodriguez
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, United States; Rutgers-Robert Wood Johnson Medical School, Department of Obstetrics, Gynecology and Reproductive Sciences, 125 Paterson Street, New Brunswick, NJ 08901, United States.
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Sodium selenate activated Wnt/β-catenin signaling and repressed amyloid-β formation in a triple transgenic mouse model of Alzheimer's disease. Exp Neurol 2017; 297:36-49. [PMID: 28711506 DOI: 10.1016/j.expneurol.2017.07.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 05/21/2017] [Accepted: 07/11/2017] [Indexed: 02/07/2023]
Abstract
Accumulating evidences show that selenium dietary intake is inversely associated with the mortality of Alzheimer's disease (AD). Sodium selenate has been reported to reduce neurofibrillary tangles (NFT) in the tauopathic mouse models, but its effects on the Wnt/β-catenin signaling pathway and APP processing remain unknown during AD formation. In this paper, triple transgenic AD mice (3×Tg-AD) had been treated with sodium selenate in drinking water for 10month before the detection of hippocampal pathology. Increased Aβ generation, tau hyperphosphorylation and neuronal apoptosis were found in the hippocampus of AD model mouse. Down-regulation of Wnt/β-catenin signaling is closely associated with the alteration of AD pathology. Treatment with sodium selenate significantly promoted the activity of protein phosphatases of type 2A (PP2A) and repressed the hallmarks of AD. Activation of PP2A by sodium selenate could increase active β-catenin level and inhibit GSK3β activity in the hippocampal tissue and primarily cultured neurons of AD model mouse, leading to activation of Wnt/β-catenin signaling and transactivation of target genes, including positively-regulated genes c-myc, survivin, TXNRD2 and negatively-regulated gene BACE1. Meanwhile, APP phosphorylation was also reduced on the Thr668 residue after selenate treatment, causing the decreases of APP cleavage and Aβ generation. These findings reveal that the Wnt/β-catenin signaling is a potential target for prevention of AD and sodium selenate may be developed as a new drug for AD treatment.
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20
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Sánchez-Elexpuru G, Serratosa JM, Sánchez MP. Sodium selenate treatment improves symptoms and seizure susceptibility in a malin-deficient mouse model of Lafora disease. Epilepsia 2017; 58:467-475. [PMID: 28098937 DOI: 10.1111/epi.13656] [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] [Accepted: 11/30/2016] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To search for new therapies aimed at ameliorating the neurologic symptoms and epilepsy developing in patients with Lafora disease. METHODS Lafora disease is caused by loss-of-function mutations in either the EPM2A or EPM2B genes. Epm2a-/- and Epm2b-/- mice display neurologic and behavioral abnormalities similar to those found in patients. Selenium is a potent antioxidant and its deficiency has been related to the development of certain diseases, including epilepsy. In this study, we investigated whether sodium selenate treatment improved the neurologic alterations and the hyperexcitability present in the Epm2b-/- mouse model. RESULTS Sodium selenate ameliorates some of the motor and memory deficits and the sensitivity observed with pentylenetetrazol (PTZ) treatments in Epm2b-/- mice. Neuronal degeneration and gliosis were also diminished after sodium selenate treatment. SIGNIFICANCE Sodium selenate could be beneficial for ameliorating some symptoms that present in patients with Lafora disease.
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Affiliation(s)
- Gentzane Sánchez-Elexpuru
- Laboratory of Neurology, IIS-Jiménez Díaz Foundation, UAM, Madrid, Spain.,Biomedical Research Network Center on Rare Diseases (CIBERER), Madrid, Spain
| | - José M Serratosa
- Laboratory of Neurology, IIS-Jiménez Díaz Foundation, UAM, Madrid, Spain.,Biomedical Research Network Center on Rare Diseases (CIBERER), Madrid, Spain
| | - Marina P Sánchez
- Laboratory of Neurology, IIS-Jiménez Díaz Foundation, UAM, Madrid, Spain.,Biomedical Research Network Center on Rare Diseases (CIBERER), Madrid, Spain
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21
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Brady R, Grills B, Romano T, Wark J, O’Brien T, Shultz S, McDonald S. Sodium selenate treatment mitigates reduction of bone volume following traumatic brain injury in rats. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2016; 16:369-376. [PMID: 27973389 PMCID: PMC5259578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVES Administration of sodium selenate to rats given traumatic brain injury (TBI) attenuates brain damage and improves long-term behavioural outcomes. We have previously provided evidence that TBI causes bone loss in rats, however the effect of sodium selenate treatment on bone quantity following TBI is unknown. METHODS Rats were randomly assigned into sham injury or fluid percussion injury (FPI) groups and administered saline or sodium selenate for 12 weeks post-injury. Femora were analysed using histomorphometry, peripheral quantitative computed tomography (pQCT) and biomechanical testing. RESULTS Distal metaphyseal trabecular bone volume fraction of FPI-selenate rats was higher than FPI-vehicle rats (41.8%; p<0.01), however, femora from selenate-treated groups were shorter in length (4.3%; p<0.01) and had increased growth plate width (22.1%; p<0.01), indicating that selenate impaired long bone growth. pQCT analysis demonstrated that distal metaphyseal cortical thickness was decreased in TBI rats compared to shams (11.7%; p<0.05), however selenate treatment to TBI animals offset this reduction (p<0.05). At the midshaft we observed no differences in biomechanical measures. CONCLUSION These are the first findings to indicate that mitigating TBI-induced neuropathology may have the added benefit of preventing osteoporosis and associated fracture risk following TBI.
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Affiliation(s)
- R.D. Brady
- Department of Physiology, Anatomy and Microbiology, La Trobe University, VIC, 3086
| | - B.L. Grills
- Department of Physiology, Anatomy and Microbiology, La Trobe University, VIC, 3086
| | - T. Romano
- Department of Physiology, Anatomy and Microbiology, La Trobe University, VIC, 3086
| | - J.D. Wark
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, VIC, 3010, Australia
| | - T.J. O’Brien
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, VIC, 3010, Australia
| | - S.R. Shultz
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, VIC, 3010, Australia
| | - S.J. McDonald
- Department of Physiology, Anatomy and Microbiology, La Trobe University, VIC, 3086,Corresponding author: Stuart McDonald, Department of Physiology, Anatomy and Microbiology, La Trobe University, VIC, 3086, Australia E-mail:
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Sodium selenate, a protein phosphatase 2A activator, mitigates hyperphosphorylated tau and improves repeated mild traumatic brain injury outcomes. Neuropharmacology 2016; 108:382-93. [DOI: 10.1016/j.neuropharm.2016.05.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 04/26/2016] [Accepted: 05/03/2016] [Indexed: 12/14/2022]
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23
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Malpas CB, Vivash L, Genc S, Saling MM, Desmond P, Steward C, Hicks RJ, Callahan J, Brodtmann A, Collins S, Macfarlane S, Corcoran NM, Hovens CM, Velakoulis D, O’Brien TJ. A Phase IIa Randomized Control Trial of VEL015 (Sodium Selenate) in Mild-Moderate Alzheimer’s Disease. J Alzheimers Dis 2016; 54:223-32. [DOI: 10.3233/jad-160544] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Charles B. Malpas
- Melbourne Brain Centre, The Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Melbourne, VIC, Australia
- Melbourne School of Psychological Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Lucy Vivash
- Melbourne Brain Centre, The Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Melbourne, VIC, Australia
| | - Sila Genc
- Melbourne Brain Centre, The Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Melbourne, VIC, Australia
- Department of Radiology, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | - Michael M. Saling
- Melbourne School of Psychological Sciences, University of Melbourne, Melbourne, VIC, Australia
- Department of Neuropsychology, Austin Health, Melbourne, VIC, Australia
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Austin Hospital, Melbourne, VIC, Australia
| | - Patricia Desmond
- Department of Radiology, University of Melbourne, Melbourne, VIC, Australia
- Department of Radiology, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | - Christopher Steward
- Department of Radiology, University of Melbourne, Melbourne, VIC, Australia
- Department of Radiology, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | - Rodney J. Hicks
- Department of Radiology, University of Melbourne, Melbourne, VIC, Australia
- Centre for Molecular Imaging, Peter MacCallum Cancer Institute, Melbourne, VIC, Australia
| | - Jason Callahan
- Centre for Molecular Imaging, Peter MacCallum Cancer Institute, Melbourne, VIC, Australia
| | - Amy Brodtmann
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Austin Hospital, Melbourne, VIC, Australia
- Eastern Cognitive Disorders Clinic, Department of Neurology, Eastern Health, Monash University, Melbourne, VIC, Australia
| | - Steven Collins
- Department of Medicine, Royal Melbourne Hospital, Melbourne, VIC, Australia
- Department of Clinical Neurosciences and Neurological Research, St Vincent’s Hospital, Melbourne, Australia
| | | | - Niall M. Corcoran
- Department of Surgery, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | | | - Dennis Velakoulis
- Melbourne Neuropsychiatry Centre, Royal Melbourne Hospital, Melbourne, VIC, Australia
- Department of Psychiatry, Melbourne, VIC, Australia
| | - Terence J. O’Brien
- Melbourne Brain Centre, The Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Melbourne, VIC, Australia
- Department of Medicine, Royal Melbourne Hospital, Melbourne, VIC, Australia
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24
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Aaseth J, Alexander J, Bjørklund G, Hestad K, Dusek P, Roos PM, Alehagen U. Treatment strategies in Alzheimer's disease: a review with focus on selenium supplementation. Biometals 2016; 29:827-39. [PMID: 27530256 PMCID: PMC5034004 DOI: 10.1007/s10534-016-9959-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 07/25/2016] [Indexed: 12/18/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder presenting one of the biggest healthcare challenges in developed countries. No effective treatment exists. In recent years the main focus of AD research has been on the amyloid hypothesis, which postulates that extracellular precipitates of beta amyloid (Aβ) derived from amyloid precursor protein (APP) are responsible for the cognitive impairment seen in AD. Treatment strategies have been to reduce Aβ production through inhibition of enzymes responsible for its formation, or to promote resolution of existing cerebral Aβ plaques. However, these approaches have failed to demonstrate significant cognitive improvements. Intracellular rather than extracellular events may be fundamental in AD pathogenesis. Selenate is a potent inhibitor of tau hyperphosphorylation, a critical step in the formation of neurofibrillary tangles. Some selenium (Se) compounds e.g. selenoprotein P also appear to protect APP against excessive copper and iron deposition. Selenoproteins show anti-inflammatory properties, and protect microtubules in the neuronal cytoskeleton. Optimal function of these selenoenzymes requires higher Se intake than what is common in Europe and also higher intake than traditionally recommended. Supplementary treatment with N-acetylcysteine increases levels of the antioxidative cofactor glutathione and can mediate adjuvant protection. The present review discusses the role of Se in AD treatment and suggests strategies for AD prevention by optimizing selenium intake, in accordance with the metal dysregulation hypothesis. This includes in particular secondary prevention by selenium supplementation to elderly with mild cognitive impairment.
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Affiliation(s)
- Jan Aaseth
- Department of Research, Innlandet Hospital Trust, Brumunddal, Norway.,Department of Public Health, Hedmark University of Applied Sciences, Elverum, Norway
| | - Jan Alexander
- Norwegian Institute of Public Health, Oslo, Norway.,Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Mo i Rana, Norway
| | - Knut Hestad
- Department of Research, Innlandet Hospital Trust, Brumunddal, Norway.,Department of Public Health, Hedmark University of Applied Sciences, Elverum, Norway
| | - Petr Dusek
- Department of Neurology and Center of Clinical Neuroscience, Charles University in Prague, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Per M Roos
- Institute of Environmental Medicine, IMM, Karolinska Institutet, Nobels väg 13, Box 210, 17177, Stockholm, Sweden. .,Department of Clinical Physiology, St.Goran Hospital, Stockholm, Sweden.
| | - Urban Alehagen
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
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25
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Liu SJ, Zheng P, Wright DK, Dezsi G, Braine E, Nguyen T, Corcoran NM, Johnston LA, Hovens CM, Mayo JN, Hudson M, Shultz SR, Jones NC, O'Brien TJ. Sodium selenate retards epileptogenesis in acquired epilepsy models reversing changes in protein phosphatase 2A and hyperphosphorylated tau. Brain 2016; 139:1919-38. [PMID: 27289302 DOI: 10.1093/brain/aww116] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 04/11/2016] [Indexed: 11/14/2022] Open
Abstract
There are no treatments in clinical practice known to mitigate the neurobiological processes that convert a healthy brain into an epileptic one, a phenomenon known as epileptogenesis. Downregulation of protein phosphatase 2A, a protein that causes the hyperphosphorylation of tau, is implicated in neurodegenerative diseases commonly associated with epilepsy, such as Alzheimer's disease and traumatic brain injury. Here we used the protein phosphatase 2A activator sodium selenate to investigate the role of protein phosphatase 2A in three different rat models of epileptogenesis: amygdala kindling, post-kainic acid status epilepticus, and post-traumatic epilepsy. Protein phosphatase 2A activity was decreased, and tau phosphorylation increased, in epileptogenic brain regions in all three models. Continuous sodium selenate treatment mitigated epileptogenesis and prevented the biochemical abnormalities, effects which persisted after drug withdrawal. Our studies indicate that limbic epileptogenesis is associated with downregulation of protein phosphatase 2A and the hyperphosphorylation of tau, and that targeting this mechanism with sodium selenate is a potential anti-epileptogenic therapy.
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Affiliation(s)
- Shi-Jie Liu
- 1 Department of Medicine, Melbourne Brain Centre, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Ping Zheng
- 1 Department of Medicine, Melbourne Brain Centre, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - David K Wright
- 2 The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia 3 Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Gabi Dezsi
- 1 Department of Medicine, Melbourne Brain Centre, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Emma Braine
- 1 Department of Medicine, Melbourne Brain Centre, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Thanh Nguyen
- 4 Department of Surgery, Melbourne Brain Centre, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Niall M Corcoran
- 4 Department of Surgery, Melbourne Brain Centre, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Leigh A Johnston
- 2 The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia 5 Department of Electrical and Electronic Engineering, The University of Melbourne, Parkville, VIC, Australia
| | - Christopher M Hovens
- 4 Department of Surgery, Melbourne Brain Centre, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Jamie N Mayo
- 1 Department of Medicine, Melbourne Brain Centre, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Matthew Hudson
- 1 Department of Medicine, Melbourne Brain Centre, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Sandy R Shultz
- 1 Department of Medicine, Melbourne Brain Centre, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Nigel C Jones
- 1 Department of Medicine, Melbourne Brain Centre, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Terence J O'Brien
- 1 Department of Medicine, Melbourne Brain Centre, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia 6 Department of Neurology, Melbourne Brain Centre, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
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26
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Choi AR, Jee Jo M, Jung MJ, Sik Kim H, Yoon S. Selenate specifically sensitizes drug-resistant cancer cells by increasing apoptosis via G2 phase cell cycle arrest without P-GP inhibition. Eur J Pharmacol 2015; 764:63-69. [PMID: 26134503 DOI: 10.1016/j.ejphar.2015.06.046] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/02/2015] [Accepted: 06/25/2015] [Indexed: 01/09/2023]
Abstract
The purpose of this study was to identify conditions that will increase the sensitivity of drug-resistant cancer cells. Selenium derivatives have been shown to present anti-cancer properties in the clinic. Currently, selenate, selenite, selenomethionine (SeMet), methyl-selenocysteine (MSC), and methaneselenic acid (MSA) are the most common selenium derivatives used as drugs in humans. Herein, we tested whether these selenium derivatives can sensitize KBV20C cancer cells, which are highly resistant to anti-cancer drugs such as vincristine. All five drugs could sensitize KBV20C cells to the same extent as they sensitized the sensitive parent KB cells, suggesting that selenium-derived drugs can be used for drug-resistant cancer cells. We also observed that these drugs did not inhibit the P-glycoprotein (P-gp) pumping-out ability, suggesting that the sensitization by selenium-derived drugs does not depend on P-gp activity in resistant KBV20C cells. Interestingly, using a cell viability assay, microscopic observation, and Hoechst staining, we found that selenate highly sensitized drug-resistant KBV20C cells by activating the apoptotic pathway, when compared to sensitive KB cells. Furthermore, we investigated why selenate sensitizes resistant KBV20C cells. Selenate-induced toxicity was associated with an increase in G2-phase cell cycle arrest in KBV20C cells, suggesting that the selenate-induced increase in apoptosis resulted from cell cycle arrest in resistant KBV20C cells. Our findings may contribute to the development of selenate-based therapies for patients resistant to cancer drugs.
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Affiliation(s)
- Ae-Ran Choi
- Research Institute, National Cancer Center, Ilsan-gu, Goyang-si, Gyeonggi-do, Republic of Korea
| | - Min Jee Jo
- Research Institute, National Cancer Center, Ilsan-gu, Goyang-si, Gyeonggi-do, Republic of Korea
| | - Myung-Ji Jung
- Research Institute, National Cancer Center, Ilsan-gu, Goyang-si, Gyeonggi-do, Republic of Korea
| | - Hyung Sik Kim
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - Sungpil Yoon
- Research Institute, National Cancer Center, Ilsan-gu, Goyang-si, Gyeonggi-do, Republic of Korea.
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27
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Cristóbal I, González-Alonso P, Daoud L, Solano E, Torrejón B, Manso R, Madoz-Gúrpide J, Rojo F, García-Foncillas J. Activation of the Tumor Suppressor PP2A Emerges as a Potential Therapeutic Strategy for Treating Prostate Cancer. Mar Drugs 2015; 13:3276-86. [PMID: 26023836 PMCID: PMC4483628 DOI: 10.3390/md13063276] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 05/13/2015] [Indexed: 12/29/2022] Open
Abstract
Protein phosphatase 2A (PP2A) is a tumor suppressor complex that has recently been reported as a novel and highly relevant molecular target in prostate cancer (PCa). However, its potential therapeutic value remains to be fully clarified. We treated PC-3 and LNCaP cell lines with the PP2A activators forskolin and FTY720 alone or combined with the PP2A inhibitor okadaic acid. We examined PP2A activity, cell growth, prostasphere formation, levels of PP2A phosphorylation, CIP2A and SET expression, and AKT and ERK activation. Interestingly, both forskolin and FTY720 dephosphorylated and activated PP2A, impairing proliferation and prostasphere formation and inducing changes in AKT and ERK phosphorylation. Moreover, FTY720 led to reduced CIP2A levels. Treatment with okadaic acid impaired PP2A activation thus demonstrating the antitumoral PP2A-dependent mechanism of action of both forskolin and FTY720. Levels of PP2A phosphorylation together with SET and CIP2A protein expression were studied in 24 PCa patients and both were associated with high Gleason scores and presence of metastatic disease. Altogether, our results suggest that PP2A inhibition could be involved in PCa progression, and the use of PP2A-activating drugs might represent a novel alternative therapeutic strategy for treating PCa patients.
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Affiliation(s)
- Ion Cristóbal
- Translational Oncology Division, Oncohealth Institute, IIS-Fundacion Jimenez Diaz, UAM, University Hospital “Fundacion Jimenez Diaz”, E-28040 Madrid, Spain; E-Mail:
- Authors to whom correspondence should be addressed; E-Mails: (I.C.); (F.R.); (J.G.-F.); Tel.: +34-915504800 (ext. 2824)
| | - Paula González-Alonso
- Group of Cancer Biomarkers, Pathology Department, IIS-Fundacion Jimenez Diaz, UAM, E-28040 Madrid, Spain; E-Mails: (P.G.-A.); (L.D.); (E.S.); (R.M.); (J.M.-G.)
| | - Lina Daoud
- Group of Cancer Biomarkers, Pathology Department, IIS-Fundacion Jimenez Diaz, UAM, E-28040 Madrid, Spain; E-Mails: (P.G.-A.); (L.D.); (E.S.); (R.M.); (J.M.-G.)
| | - Esther Solano
- Group of Cancer Biomarkers, Pathology Department, IIS-Fundacion Jimenez Diaz, UAM, E-28040 Madrid, Spain; E-Mails: (P.G.-A.); (L.D.); (E.S.); (R.M.); (J.M.-G.)
| | - Blanca Torrejón
- Translational Oncology Division, Oncohealth Institute, IIS-Fundacion Jimenez Diaz, UAM, University Hospital “Fundacion Jimenez Diaz”, E-28040 Madrid, Spain; E-Mail:
| | - Rebeca Manso
- Group of Cancer Biomarkers, Pathology Department, IIS-Fundacion Jimenez Diaz, UAM, E-28040 Madrid, Spain; E-Mails: (P.G.-A.); (L.D.); (E.S.); (R.M.); (J.M.-G.)
| | - Juan Madoz-Gúrpide
- Group of Cancer Biomarkers, Pathology Department, IIS-Fundacion Jimenez Diaz, UAM, E-28040 Madrid, Spain; E-Mails: (P.G.-A.); (L.D.); (E.S.); (R.M.); (J.M.-G.)
| | - Federico Rojo
- Group of Cancer Biomarkers, Pathology Department, IIS-Fundacion Jimenez Diaz, UAM, E-28040 Madrid, Spain; E-Mails: (P.G.-A.); (L.D.); (E.S.); (R.M.); (J.M.-G.)
- Authors to whom correspondence should be addressed; E-Mails: (I.C.); (F.R.); (J.G.-F.); Tel.: +34-915504800 (ext. 2824)
| | - Jesús García-Foncillas
- Translational Oncology Division, Oncohealth Institute, IIS-Fundacion Jimenez Diaz, UAM, University Hospital “Fundacion Jimenez Diaz”, E-28040 Madrid, Spain; E-Mail:
- Authors to whom correspondence should be addressed; E-Mails: (I.C.); (F.R.); (J.G.-F.); Tel.: +34-915504800 (ext. 2824)
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28
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Shultz SR, Wright DK, Zheng P, Stuchbery R, Liu SJ, Sashindranath M, Medcalf RL, Johnston LA, Hovens CM, Jones NC, O'Brien TJ. Sodium selenate reduces hyperphosphorylated tau and improves outcomes after traumatic brain injury. Brain 2015; 138:1297-313. [PMID: 25771151 DOI: 10.1093/brain/awv053] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 01/10/2015] [Indexed: 12/14/2022] Open
Abstract
Traumatic brain injury is a common and serious neurodegenerative condition that lacks a pharmaceutical intervention to improve long-term outcome. Hyperphosphorylated tau is implicated in some of the consequences of traumatic brain injury and is a potential pharmacological target. Protein phosphatase 2A is a heterotrimeric protein that regulates key signalling pathways, and protein phosphatase 2A heterotrimers consisting of the PR55 B-subunit represent the major tau phosphatase in the brain. Here we investigated whether traumatic brain injury in rats and humans would induce changes in protein phosphatase 2A and phosphorylated tau, and whether treatment with sodium selenate-a potent PR55 activator-would reduce phosphorylated tau and improve traumatic brain injury outcomes in rats. Ninety young adult male Long-Evans rats were administered either a fluid percussion injury or sham-injury. A proportion of rats were killed at 2, 24, and 72 h post-injury to assess acute changes in protein phosphatase 2A and tau. Other rats were given either sodium selenate or saline-vehicle treatment that was continuously administered via subcutaneous osmotic pump for 12 weeks. Serial magnetic resonance imaging was acquired prior to, and at 1, 4, and 12 weeks post-injury to assess evolving structural brain damage and axonal injury. Behavioural impairments were assessed at 12 weeks post-injury. The results showed that traumatic brain injury in rats acutely reduced PR55 expression and protein phosphatase 2A activity, and increased the expression of phosphorylated tau and the ratio of phosphorylated tau to total tau. Similar findings were seen in post-mortem brain samples from acute human traumatic brain injury patients, although many did not reach statistical significance. Continuous sodium selenate treatment for 12 weeks after sham or fluid percussion injury in rats increased protein phosphatase 2A activity and PR55 expression, and reduced the ratio of phosphorylated tau to total tau, attenuated brain damage, and improved behavioural outcomes in rats given a fluid percussion injury. Notably, total tau levels were decreased in rats 12 weeks after fluid percussion injury, and several other factors, including the use of anaesthetic, the length of recovery time, and that some brain injury and behavioural dysfunction still occurred in rats treated with sodium selenate must be considered in the interpretation of this study. However, taken together these data suggest protein phosphatase 2A and hyperphosphorylated tau may be involved in the neurodegenerative cascade of traumatic brain injury, and support the potential use of sodium selenate as a novel traumatic brain injury therapy.
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Affiliation(s)
- Sandy R Shultz
- 1 Melbourne Brain Centre, Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - David K Wright
- 2 Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Ping Zheng
- 1 Melbourne Brain Centre, Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Ryan Stuchbery
- 3 Department of Surgery, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Shi-Jie Liu
- 1 Melbourne Brain Centre, Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Maithili Sashindranath
- 4 Australian Centre for Blood Disease, Monash University, Melbourne, Victoria, 3004, Australia
| | - Robert L Medcalf
- 4 Australian Centre for Blood Disease, Monash University, Melbourne, Victoria, 3004, Australia
| | - Leigh A Johnston
- 5 Department of Electrical and Electronic Engineering, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Christopher M Hovens
- 3 Department of Surgery, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Nigel C Jones
- 1 Melbourne Brain Centre, Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Terence J O'Brien
- 1 Melbourne Brain Centre, Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
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Selenium-Functionalized Molecules (SeFMs) as Potential Drugs and Nutritional Supplements. TOPICS IN MEDICINAL CHEMISTRY 2015. [DOI: 10.1007/7355_2015_87] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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Fernandes AP, Gandin V. Selenium compounds as therapeutic agents in cancer. Biochim Biophys Acta Gen Subj 2014; 1850:1642-60. [PMID: 25459512 DOI: 10.1016/j.bbagen.2014.10.008] [Citation(s) in RCA: 272] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/06/2014] [Accepted: 10/08/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND With cancer cells encompassing consistently higher production of reactive oxygen species (ROS) and with an induced antioxidant defense to counteract the increased basal ROS production, tumors have a limited reserve capacity resulting in an increased vulnerability of some cancer cells to ROS. Based on this, oxidative stress has been recognized as a tumor-specific target for the rational design of new anticancer agents. Among redox modulating compounds, selenium compounds have gained substantial attention due to their promising chemotherapeutic potential. SCOPE OF REVIEW This review aims in summarizing and providing the recent developments of our understanding of the molecular mechanisms that underlie the potential anticancer effects of selenium compounds. MAJOR CONCLUSIONS It is well established that selenium at higher doses readily can turn into a prooxidant and thereby exert its potential anticancer properties. However, the biological activity of selenium compounds and the mechanism behind these effects are highly dependent on its speciation and the specific metabolic pathways of cells and tissues. Conversely, the chemical properties and the main molecular mechanisms of the most relevant inorganic and organic selenium compounds as well as selenium-based nanoparticles must be taken into account and are discussed herein. GENERAL SIGNIFICANCE Elucidating and deepening our mechanistic knowledge of selenium compounds will help in designing and optimizing compounds with more specific antitumor properties for possible future application of selenium compounds in the treatment of cancer. This article is part of a Special Issue entitled Redox regulation of differentiation and de-differentiation.
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Affiliation(s)
- Aristi P Fernandes
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics (MBB), Karolinska Institutet, SE-171 77 Stockholm, Sweden.
| | - Valentina Gandin
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via Marzolo 5, 35131 Padova, Italy
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Stebbing J, Lit LC, Zhang H, Darrington RS, Melaiu O, Rudraraju B, Giamas G. The regulatory roles of phosphatases in cancer. Oncogene 2014; 33:939-53. [PMID: 23503460 DOI: 10.1038/onc.2013.80] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 02/01/2013] [Indexed: 02/06/2023]
Abstract
The relevance of potentially reversible post-translational modifications required for controlling cellular processes in cancer is one of the most thriving arenas of cellular and molecular biology. Any alteration in the balanced equilibrium between kinases and phosphatases may result in development and progression of various diseases, including different types of cancer, though phosphatases are relatively under-studied. Loss of phosphatases such as PTEN (phosphatase and tensin homologue deleted on chromosome 10), a known tumour suppressor, across tumour types lends credence to the development of phosphatidylinositol 3-kinase inhibitors alongside the use of phosphatase expression as a biomarker, though phase 3 trial data are lacking. In this review, we give an updated report on phosphatase dysregulation linked to organ-specific malignancies.
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Affiliation(s)
- J Stebbing
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - L C Lit
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - H Zhang
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - R S Darrington
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - O Melaiu
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - B Rudraraju
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - G Giamas
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
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Tsukamoto T, Hama S, Kogure K, Tsuchiya H. Selenate induces epithelial–mesenchymal transition in a colorectal carcinoma cell line by AKT activation. Exp Cell Res 2013; 319:1913-1921. [DOI: 10.1016/j.yexcr.2013.05.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 05/29/2013] [Accepted: 05/31/2013] [Indexed: 11/29/2022]
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33
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The molecular mechanisms of antimetastatic ruthenium compounds explored through DIGE proteomics. J Inorg Biochem 2013; 118:94-9. [DOI: 10.1016/j.jinorgbio.2012.10.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 10/02/2012] [Accepted: 10/04/2012] [Indexed: 01/04/2023]
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34
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Targeting phosphatases as the next generation of disease modifying therapeutics for Parkinson’s disease. Neurochem Int 2012; 61:899-906. [DOI: 10.1016/j.neuint.2012.01.031] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 01/26/2012] [Accepted: 01/28/2012] [Indexed: 12/15/2022]
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35
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Targeting hyperphosphorylated tau with sodium selenate suppresses seizures in rodent models. Neurobiol Dis 2012; 45:897-901. [DOI: 10.1016/j.nbd.2011.12.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 11/03/2011] [Accepted: 12/04/2011] [Indexed: 11/18/2022] Open
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Voronkov M, Braithwaite SP, Stock JB. Phosphoprotein phosphatase 2A: a novel druggable target for Alzheimer's disease. Future Med Chem 2011; 3:821-33. [PMID: 21644827 PMCID: PMC3292348 DOI: 10.4155/fmc.11.47] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Tau hyperphosphorylation is thought to play an important role in the etiology of Alzheimer's disease by facilitating the formation of neurofibrillary tangles. Reducing phosphorylation through kinase inhibition has therefore emerged as a target for drug development, but despite considerable efforts to develop therapeutic kinase inhibitors, success has been limited. An alternative approach is to develop pharmaceuticals to enhance the activity of the principal phospho-tau phosphatase, phosphoprotein phosphatase 2A (PP2A). In this article we review evidence that this mechanism is pharmacologically achievable and has promise for delivering the next generation of Alzheimer's disease therapeutics. A number of different chemotypes have been reported to lead to enhanced PP2A activity through a range of proposed mechanisms. Some of these compounds appear to act directly as allosteric activators of PP2A, while others act indirectly by inhibiting the binding of PP2A inhibitors or by altering post-translational modifications that act in turn to regulate PP2A activity towards phospho-tau. These results indicate that PP2A may provide a useful target that can be safely, selectively and effectively modulated through pharmaceutical intervention to treat Alzheimer's disease.
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Affiliation(s)
| | | | - Jeffry B Stock
- Signum Biosciences, Monmouth Junction, NJ 08852, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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Bhattacharya A. Methylselenocysteine: a promising antiangiogenic agent for overcoming drug delivery barriers in solid malignancies for therapeutic synergy with anticancer drugs. Expert Opin Drug Deliv 2011; 8:749-63. [PMID: 21473705 DOI: 10.1517/17425247.2011.571672] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Despite progress, chemotherapeutic response in solid malignancies has remained limited. Although initial results of the use of antiangiogenic agents in combination chemotherapy indicated an enhanced therapeutic response, recent data indicate that the surviving cancer is not only able to surmount therapy, but also actually able to adapt a more aggressive metastatic phenotype. Thus, selecting an antiangiogenic agent that is less likely to lead to tumor resurgence is a key to future therapeutic success of antiangiogenic agents in a combinatorial setting. AREAS COVERED Against the broad spectrum of antiangiogenic agents used at present in the clinic, the putative benefits of the use of organoselenium compounds, such as methylselenocysteine (MSC), are discussed in this review. EXPERT OPINION MSC, being part of the mammalian physiology, is a well-tolerated, versatile and economical antiangiogenic agent. It downregulates multiple key upstream tumor survival markers, and enhances tumor drug delivery, at a given systemic dose of an anticancer agent, while protecting normal tissue from cytotoxic adverse effects. Further clinical trials, especially in poorly differentiated cancers, are warranted.
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Affiliation(s)
- Arup Bhattacharya
- Roswell Park Cancer Institute, Department of Cancer Prevention and Control, Buffalo, NY 14263, USA.
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Current world literature. Curr Opin Urol 2011; 21:257-64. [PMID: 21455039 DOI: 10.1097/mou.0b013e3283462c0f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bhardwaj A, Singh S, Srivastava SK, Honkanen RE, Reed E, Singh AP. Modulation of protein phosphatase 2A activity alters androgen-independent growth of prostate cancer cells: therapeutic implications. Mol Cancer Ther 2011; 10:720-31. [PMID: 21393425 DOI: 10.1158/1535-7163.mct-10-1096] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Earlier we identified PPP2CA, which encodes for the α-isoform of protein phosphatase 2A (PP2A) catalytic subunit, as one of the downregulated genes in androgen-independent prostate cancer. PP2A is a serine/threonine phosphatase and a potent tumor suppressor involved in broad cellular functions; however, its role in prostate cancer has not yet been determined. Here, we have investigated the effect of PP2A activity modulation on the androgen-independent growth of prostate cancer cells. Our data show that the PPP2CA expression and PP2A activity is downregulated in androgen-independent (C4-2) prostate cancer cells as compared with androgen-dependent (LNCaP) cells. Downregulation of PP2A activity by pharmacologic inhibition or short interfering RNA-mediated PPP2CA silencing sustains the growth of LNCaP cells under an androgen-deprived condition by relieving the androgen deprivation-induced cell-cycle arrest and preventing apoptosis. Immunoblot analyses reveal enhanced phosphorylation of Akt, extracellular signal-regulated kinase (ERK), BAD, increased expression of cyclins (A1/D1), and decreased expression of cyclin inhibitor (p27) on PP2A downregulation. Furthermore, our data show that androgen receptor (AR) signaling is partially maintained in PP2A-inhibited cells through increased AR expression and ligand-independent phosphorylation. Pharmacologic inhibition of Akt, ERK, and AR suggest a role of these signaling pathways in facilitating the androgen-independent growth of LNCaP cells. These observations are supported by the effect of ceramide, a PP2A activator, on androgen-independent C4-2 cells. Ceramide inhibited the growth of C4-2 cells on androgen deprivation, an effect that could be abrogated by PP2A downregulation. Altogether, our findings suggest that modulation of PP2A activity may represent an alternative therapeutic approach for the treatment of advanced androgen-independent prostate cancer.
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Affiliation(s)
- Arun Bhardwaj
- Department of Oncologic Sciences Mitchell Cancer Institute, University of South Alabama 1660 Springhill Avenue, Mobile, AL 36604, USA
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