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Hector M, Langmann T, Wolf A. Translocator protein (18 kDa) (Tspo) in the retina and implications for ocular diseases. Prog Retin Eye Res 2024; 100:101249. [PMID: 38430990 DOI: 10.1016/j.preteyeres.2024.101249] [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: 12/05/2023] [Revised: 02/28/2024] [Accepted: 02/29/2024] [Indexed: 03/05/2024]
Abstract
Translocator protein (18 kDa) (Tspo), formerly known as peripheral benzodiazepine receptor is a highly conserved transmembrane protein primarily located in the outer mitochondrial membrane. In the central nervous system (CNS), especially in glia cells, Tspo is upregulated upon inflammation. Consequently, Tspo was used as a tool for diagnostic in vivo imaging of neuroinflammation in the brain and as a potential therapeutic target. Several synthetic Tspo ligands have been explored as immunomodulatory and neuroprotective therapy approaches. Although the function of Tspo and how its ligands exert these beneficial effects is not fully clear, it became a research topic of interest, especially in ocular diseases in the past few years. This review summarizes state-of-the-art knowledge of Tspo expression and its proposed functions in different cells of the retina including microglia, retinal pigment epithelium and Müller cells. Tspo is involved in cytokine signaling, oxidative stress and reactive oxygen species production, calcium signaling, neurosteroid synthesis, energy metabolism, and cholesterol efflux. We also highlight recent developments in preclinical models targeting Tspo and summarize the relevance of Tspo biology for ocular and retinal diseases. We conclude that glial upregulation of Tspo in different ocular pathologies and the use of Tspo ligands as promising therapeutic approaches in preclinical studies underline the importance of Tspo as a potential disease-modifying protein.
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Affiliation(s)
- Mandy Hector
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Centre for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
| | - Anne Wolf
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Centre for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.
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2
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Wang J, Ren P, Zeng Z, Ma L, Li Y, Zhang H, Guo W. Inhibition of translocator protein 18 kDa suppressed the progression of glioma via the ELAV-like RNA-binding protein 1/MAPK-activated protein kinase 3 axis. Bioengineered 2022; 13:7457-7470. [PMID: 35285415 PMCID: PMC9208533 DOI: 10.1080/21655979.2022.2048992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Jingya Wang
- Department of Anesthesiology, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, Dongcheng,China
- Department of Gastroenterology, The Affiliated Hospital of Weifang Medical University, Weifang, Shandong, China
- Guizhou Provincial Key Laboratory of Pathogenesis & Drug Research on Common Chronic Diseases, Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang, Guizhou, China
| | - Peng Ren
- Department of Anesthesiology, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, Dongcheng,China
| | - Zhirui Zeng
- Guizhou Provincial Key Laboratory of Pathogenesis & Drug Research on Common Chronic Diseases, Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang, Guizhou, China
| | - Li Ma
- Department of Anesthesiology, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, Dongcheng,China
| | - Yunjun Li
- Department of Neurosurgery, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, Dongcheng, China
| | - Hongmei Zhang
- Department of Gastroenterology, The Affiliated Hospital of Weifang Medical University, Weifang, Shandong, China
| | - Wenzhi Guo
- Department of Anesthesiology, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, Dongcheng,China
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3
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Hattori Y, Ishimura M, Ohta Y, Takenaka H, Kawabata S, Kirihata M. Dodecaborate Conjugates Targeting Tumor Cell Overexpressing Translocator Protein for Boron Neutron Capture Therapy. ACS Med Chem Lett 2021; 13:50-54. [PMID: 35059123 PMCID: PMC8762747 DOI: 10.1021/acsmedchemlett.1c00377] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 11/29/2021] [Indexed: 01/16/2023] Open
Abstract
We developed novel closo-dodecaborate ([B12H11]2-) anion-containing translocator protein (TSPO) ligand as a boron carrier for boron neutron capture therapy. This compound shows high water solubility and can deliver boron to TSPO highly expressed in breast cancer cells. We describe the synthesis and in vitro evaluation of a dodecaborate-based pyrazolopyrimidine.
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Affiliation(s)
- Yoshihide Hattori
- Research
Center of Boron Neutron Capture Therapy, Osaka Prefecture University, 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan,
| | - Miki Ishimura
- Research
Center of Boron Neutron Capture Therapy, Osaka Prefecture University, 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan,Stella
Pharma Co., ORIX Kouraibashi
Bldg., 3-2-7 Kouraibashi, Chuo-ku, Osaka 541-0043, Japan
| | - Youichirou Ohta
- Research
Center of Boron Neutron Capture Therapy, Osaka Prefecture University, 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan,Stella
Pharma Co., ORIX Kouraibashi
Bldg., 3-2-7 Kouraibashi, Chuo-ku, Osaka 541-0043, Japan
| | - Hiroshi Takenaka
- Research
Center of Boron Neutron Capture Therapy, Osaka Prefecture University, 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan,Stella
Pharma Co., ORIX Kouraibashi
Bldg., 3-2-7 Kouraibashi, Chuo-ku, Osaka 541-0043, Japan
| | - Shinji Kawabata
- Department
of Neurosurgery, Osaka Medical and Pharmaceutical
University, 2-7 Daigaku-machi, Takatsuki-shi, Osaka 569-8686, Japan
| | - Mitsunori Kirihata
- Research
Center of Boron Neutron Capture Therapy, Osaka Prefecture University, 1-1, Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
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4
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Troike KM, Acanda de la Rocha AM, Alban TJ, Grabowski MM, Otvos B, Cioffi G, Waite KA, Barnholtz Sloan JS, Lathia JD, Guilarte TR, Azzam DJ. The Translocator Protein ( TSPO) Genetic Polymorphism A147T Is Associated with Worse Survival in Male Glioblastoma Patients. Cancers (Basel) 2021; 13:cancers13184525. [PMID: 34572751 PMCID: PMC8471762 DOI: 10.3390/cancers13184525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/27/2021] [Accepted: 09/02/2021] [Indexed: 12/20/2022] Open
Abstract
Simple Summary The translocator protein 18 kDa (TSPO) gene is highly expressed in glioblastoma (GBM), the most common primary malignant brain tumor, which remains one of the most difficult tumors to treat. TSPO is located in the outer mitochondrial membrane and binds cholesterol through its C-terminal domain. One frequent single-nucleotide polymorphism (SNP) rs6971, which changes the alanine 147 into threonine (Ala147Thr), has been found in the C-terminal domain of the TSPO region and dramatically alters the affinity with which TSPO binds drug ligands. However, the potential association between the TSPO genetic variants and GBM clinical outcomes is not known. Here, we evaluated the effects of the Ala147Thr SNP localized in this TSPO region on biological, sex-specific, overall, and progression-free GBM survival. Our findings suggest an association between the TSPO rs6971 variant and adverse outcomes in male GBM patients but not in females. These findings also suggest that the TSPO rs6971 SNP could be used as a prognostic marker of survival in GBM patients. Abstract Glioblastoma (GBM) is the most common primary brain tumor in adults, with few available therapies and a five-year survival rate of 7.2%. Hence, strategies for improving GBM prognosis are urgently needed. The translocator protein 18kDa (TSPO) plays crucial roles in essential mitochondria-based physiological processes and is a validated biomarker of neuroinflammation, which is implicated in GBM progression. The TSPO gene has a germline single nucleotide polymorphism, rs6971, which is the most common SNP in the Caucasian population. High TSPO gene expression is associated with reduced survival in GBM patients; however, the relation between the most frequent TSPO genetic variant and GBM pathogenesis is not known. The present study retrospectively analyzed the correlation of the TSPO polymorphic variant rs6971 with overall and progression-free survival in GBM patients using three independent cohorts. TSPO rs6971 polymorphism was significantly associated with shorter overall survival and progression-free survival in male GBM patients but not in females in one large cohort of 441 patients. We observed similar trends in two other independent cohorts. These observations suggest that the TSPO rs6971 polymorphism could be a significant predictor of poor prognosis in GBM, with a potential for use as a prognosis biomarker in GBM patients. These results reveal for the first time a biological sex-specific relation between rs6971 TSPO polymorphism and GBM.
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Affiliation(s)
- Katie M. Troike
- Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA; (K.M.T.); (T.J.A.); (M.M.G.); (B.O.); (J.D.L.)
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA
| | - Arlet M. Acanda de la Rocha
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, USA;
| | - Tyler J. Alban
- Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA; (K.M.T.); (T.J.A.); (M.M.G.); (B.O.); (J.D.L.)
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA
| | - Matthew M. Grabowski
- Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA; (K.M.T.); (T.J.A.); (M.M.G.); (B.O.); (J.D.L.)
- Department of Neurosurgery, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Balint Otvos
- Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA; (K.M.T.); (T.J.A.); (M.M.G.); (B.O.); (J.D.L.)
- Department of Neurosurgery, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Gino Cioffi
- National Cancer Institute, Division of Cancer Epidemiology and Genetics, Trans-Divisional Research Program, Bethesda, MD 20892, USA; (G.C.); (K.A.W.); (J.S.B.S.)
| | - Kristin A. Waite
- National Cancer Institute, Division of Cancer Epidemiology and Genetics, Trans-Divisional Research Program, Bethesda, MD 20892, USA; (G.C.); (K.A.W.); (J.S.B.S.)
| | - Jill S. Barnholtz Sloan
- National Cancer Institute, Division of Cancer Epidemiology and Genetics, Trans-Divisional Research Program, Bethesda, MD 20892, USA; (G.C.); (K.A.W.); (J.S.B.S.)
- National Cancer Institute, Center for Biomedical Informatics and Information Technology, Bethesda, MD 20892, USA
| | - Justin D. Lathia
- Department of Cardiovascular & Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA; (K.M.T.); (T.J.A.); (M.M.G.); (B.O.); (J.D.L.)
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA
- Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA
- Rose Ella Burkhardt Brain Tumor and Neuro-Oncology Center, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Tomás R. Guilarte
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, USA;
- Brain, Behavior & the Environment Program, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, USA
- Correspondence: (T.R.G.); (D.J.A.)
| | - Diana J. Azzam
- Department of Environmental Health Sciences, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL 33199, USA;
- Correspondence: (T.R.G.); (D.J.A.)
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5
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Tournier B, Ceyzériat K, Bouteldja FN, Millet P. Amyloid and Tau Induce Cell Death Independently of TSPO Polymerization and Density Changes. ACS OMEGA 2021; 6:18719-18727. [PMID: 34337211 PMCID: PMC8319921 DOI: 10.1021/acsomega.1c01678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Apoptosis-dependent cell death of astrocytes has been described in Alzheimer's disease and is linked to the presence of two markers of the pathology: the β-amyloid peptide (Aβ) and the hyperphosphorylated Tau protein. Astrocytes also show reactive states characterized by the overexpression of the 18 kDa translocator protein (TSPO). However, TSPO is also known, in other areas of research, to participate in cell proliferation and death. Regulation of its function by autopolymerization has been described, but its involvement in apoptosis remains unknown. The aim was to determine the effects of Aβ, Tau, and TSPO antagonists on proliferation/cell death and TSPO polymerization in the C6 astrocytic cell line. The dose-effect on cell death in response to Aβ and Tau was observed but without alterations of TSPO density and polymerization. In contrast, nanomolar doses of antagonists stimulated cell proliferation, although micromolar doses induced cell death with a reduction in TSPO density and an increase in the ratio between the 36 and the 72 kDa TSPO polymers. Therefore, an alteration in the density and polymerization of TSPO appears to be related to cell death induced by TSPO antagonisms. In contrast, Aβ- and Tau-induced death seems to be independent of TSPO alterations. In conclusion, even if its role in cell death and proliferation is demonstrated, TSPO seems to, in the context of Alzheimer's disease, rather represent a marker of the activity of astrocytes than of cell death.
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Affiliation(s)
- Benjamin
B. Tournier
- Department
of Psychiatry, University Hospitals of Geneva, 1205 Genève, Switzerland
- Department
of Psychiatry, University of Geneva, 1211 Genève, Switzerland
| | - Kelly Ceyzériat
- Department
of Psychiatry, University Hospitals of Geneva, 1205 Genève, Switzerland
- Department
of Psychiatry, University of Geneva, 1211 Genève, Switzerland
- Division
of Nuclear Medicine and Molecular Imaging, Diagnostic Department, University Hospitals of Geneva, 1205 Genève, Switzerland
- Division
of Radiation Oncology, Department of Oncology, University Hospitals of Geneva, 1205 Genève, Switzerland
| | - Farha N. Bouteldja
- Department
of Psychiatry, University Hospitals of Geneva, 1205 Genève, Switzerland
- Department
of Psychiatry, University of Geneva, 1211 Genève, Switzerland
| | - Philippe Millet
- Department
of Psychiatry, University Hospitals of Geneva, 1205 Genève, Switzerland
- Department
of Psychiatry, University of Geneva, 1211 Genève, Switzerland
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6
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De novo Neurosteroidogenesis in Human Microglia: Involvement of the 18 kDa Translocator Protein. Int J Mol Sci 2021; 22:ijms22063115. [PMID: 33803741 PMCID: PMC8003294 DOI: 10.3390/ijms22063115] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/06/2021] [Accepted: 03/15/2021] [Indexed: 12/14/2022] Open
Abstract
Neuroactive steroids are potent modulators of microglial functions and are capable of counteracting their excessive reactivity. This action has mainly been ascribed to neuroactive steroids released from other sources, as microglia have been defined unable to produce neurosteroids de novo. Unexpectedly, immortalized murine microglia recently exhibited this de novo biosynthesis; herein, de novo neurosteroidogenesis was characterized in immortalized human microglia. The results demonstrated that C20 and HMC3 microglial cells constitutively express members of the neurosteroidogenesis multiprotein machinery-in particular, the transduceosome members StAR and TSPO, and the enzyme CYP11A1. Moreover, both cell lines produce pregnenolone and transcriptionally express the enzymes involved in neurosteroidogenesis. The high TSPO expression levels observed in microglia prompted us to assess its role in de novo neurosteroidogenesis. TSPO siRNA and TSPO synthetic ligand treatments were used to reduce and prompt TSPO function, respectively. The TSPO expression downregulation compromised the de novo neurosteroidogenesis and led to an increase in StAR expression, probably as a compensatory mechanism. The pharmacological TSPO stimulation the de novo neurosteroidogenesis improved in turn the neurosteroid-mediated release of Brain-Derived Neurotrophic Factor. In conclusion, these results demonstrated that de novo neurosteroidogenesis occurs in human microglia, unravelling a new mechanism potentially useful for future therapeutic purposes.
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Gao ZW, Huang YY, Zhang JQ, Rong JY, Qiao GY, Chen N, Yu GD, Luo M, Liu XF. Paeoniflorin elicits the anti-proliferative effects on glioma cell via targeting translocator protein 18 KDa. J Pharmacol Sci 2020; 145:115-121. [PMID: 33357769 DOI: 10.1016/j.jphs.2020.10.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 03/17/2020] [Accepted: 04/08/2020] [Indexed: 10/23/2022] Open
Abstract
As a natural compound isolated from Paeoniae radix, Paeoniflorin (PF) has been shown the antitumor effects in various types of human cancers including glioma, which is one of the serious tumors in central nervous system. Translocator protein 18 KDa (TSPO) has been shown to be relevant to the glioma aetiology. However, the regulation of PF in TSPO and neurosteriods biosynthesis on glioma is still unclear. In the present study, the glioma cell (U87 and U251) were cultured and used to quantify the bindings of PF on TSPO. Results indicated that there was not significant different between IC50 of PF and TSPO ligand PK11195. Moreover, PF exerted the anti-proliferative effects in glioma cell with a dose dependent inhibition from 12.5 to 100 μM in vitro. Consistent with the effects of PK11195, lowered levels on progesterone, allopregnanolone, as well as TSPO mRNA were induced by PF (25 and 50 μM). Furthermore, a xenograft mouse model with U87 cell-derived was significant inhibited by PF treatment, as well as the PK11195 administration. These results demonstrate that PF exerts its antitumor effects associated with the TSPO and neurosteroids biosynthesis in glioma cells could be a promising therapeutic agent for glioma therapy.
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Affiliation(s)
- Zhuo-Wei Gao
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China; School of Traditional Chinese Medicine, Southern Medical University Guangzhou, Guangdong, 510515, China
| | - Yu-Yun Huang
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China
| | - Jia-Qi Zhang
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China
| | - Jing-Yu Rong
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China
| | - Guan-Ying Qiao
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China
| | - Nan Chen
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China
| | - Guo-Dong Yu
- Shunde Hospital of Guangzhou University of TCM, Foshan, Guangdong, 528300, China.
| | - Min Luo
- Nanfang Hospital of Southern Medical University, Guangzhou, Guangdong, 510515, China.
| | - Xiao-Fen Liu
- The Fifth Affiliated Hospital of Southern Medical University, China Guangzhou, Guangdong, 510900, China.
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Ammer LM, Vollmann-Zwerenz A, Ruf V, Wetzel CH, Riemenschneider MJ, Albert NL, Beckhove P, Hau P. The Role of Translocator Protein TSPO in Hallmarks of Glioblastoma. Cancers (Basel) 2020; 12:cancers12102973. [PMID: 33066460 PMCID: PMC7602186 DOI: 10.3390/cancers12102973] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/09/2020] [Accepted: 10/09/2020] [Indexed: 12/18/2022] Open
Abstract
Simple Summary The translocator protein (TSPO) has been under extensive investigation as a specific marker in positron emission tomography (PET) to visualize brain lesions following injury or disease. In recent years, TSPO is increasingly appreciated as a potential novel therapeutic target in cancer. In Glioblastoma (GBM), the most malignant primary brain tumor, TSPO expression levels are strongly elevated and scientific evidence accumulates, hinting at a pivotal role of TSPO in tumorigenesis and glioma progression. The aim of this review is to summarize the current literature on TSPO with respect to its role both in diagnostics and especially with regard to the critical hallmarks of cancer postulated by Hanahan and Weinberg. Overall, our review contributes to a better understanding of the functional significance of TSPO in Glioblastoma and draws attention to TSPO as a potential modulator of treatment response and thus an important factor that may influence the clinical outcome of GBM. Abstract Glioblastoma (GBM) is the most fatal primary brain cancer in adults. Despite extensive treatment, tumors inevitably recur, leading to an average survival time shorter than 1.5 years. The 18 kDa translocator protein (TSPO) is abundantly expressed throughout the body including the central nervous system. The expression of TSPO increases in states of inflammation and brain injury due to microglia activation. Not least due to its location in the outer mitochondrial membrane, TSPO has been implicated with a broad spectrum of functions. These include the regulation of proliferation, apoptosis, migration, as well as mitochondrial functions such as mitochondrial respiration and oxidative stress regulation. TSPO is frequently overexpressed in GBM. Its expression level has been positively correlated to WHO grade, glioma cell proliferation, and poor prognosis of patients. Several lines of evidence indicate that TSPO plays a functional part in glioma hallmark features such as resistance to apoptosis, invasiveness, and proliferation. This review provides a critical overview of how TSPO could regulate several aspects of tumorigenesis in GBM, particularly in the context of the hallmarks of cancer proposed by Hanahan and Weinberg in 2011.
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Affiliation(s)
- Laura-Marie Ammer
- Wilhelm Sander-NeuroOncology Unit and Department of Neurology, University Hospital Regensburg, 93053 Regensburg, Germany; (L.-M.A.); (A.V.-Z.)
| | - Arabel Vollmann-Zwerenz
- Wilhelm Sander-NeuroOncology Unit and Department of Neurology, University Hospital Regensburg, 93053 Regensburg, Germany; (L.-M.A.); (A.V.-Z.)
| | - Viktoria Ruf
- Center for Neuropathology and Prion Research, Ludwig Maximilians University of Munich, 81377 Munich, Germany;
| | - Christian H. Wetzel
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany;
| | | | - Nathalie L. Albert
- Department of Nuclear Medicine, Ludwig-Maximilians-University Munich, 81377 Munich, Germany;
| | - Philipp Beckhove
- Regensburg Center for Interventional Immunology (RCI) and Department Internal Medicine III, University Hospital Regensburg, 93053 Regensburg, Germany;
| | - Peter Hau
- Wilhelm Sander-NeuroOncology Unit and Department of Neurology, University Hospital Regensburg, 93053 Regensburg, Germany; (L.-M.A.); (A.V.-Z.)
- Correspondence:
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9
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In Vivo TSPO Signal and Neuroinflammation in Alzheimer's Disease. Cells 2020; 9:cells9091941. [PMID: 32839410 PMCID: PMC7565089 DOI: 10.3390/cells9091941] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 12/15/2022] Open
Abstract
In the last decade, positron emission tomography (PET) and single-photon emission computed tomography (SPECT) in in vivo imaging has attempted to demonstrate the presence of neuroinflammatory reactions by measuring the 18 kDa translocator protein (TSPO) expression in many diseases of the central nervous system. We focus on two pathological conditions for which neuropathological studies have shown the presence of neuroinflammation, which translates in opposite in vivo expression of TSPO. Alzheimer's disease has been the most widely assessed with more than forty preclinical and clinical studies, showing overall that TSPO is upregulated in this condition, despite differences in the topography of this increase, its time-course and the associated cell types. In the case of schizophrenia, a reduction of TSPO has instead been observed, though the evidence remains scarce and contradictory. This review focuses on the key characteristics of TSPO as a biomarker of neuroinflammation in vivo, namely, on the cellular origin of the variations in its expression, on its possible biological/pathological role and on its variations across disease phases.
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10
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Pigeon H, Pérès EA, Truillet C, Jego B, Boumezbeur F, Caillé F, Zinnhardt B, Jacobs AH, Le Bihan D, Winkeler A. TSPO-PET and diffusion-weighted MRI for imaging a mouse model of infiltrative human glioma. Neuro Oncol 2020; 21:755-764. [PMID: 30721979 DOI: 10.1093/neuonc/noz029] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Glioblastoma (GBM) is the most devastating brain tumor. Despite the use of multimodal treatments, most patients relapse, often due to the highly invasive nature of gliomas. However, the detection of glioma infiltration remains challenging. The aim of this study was to assess advanced PET and MRI techniques for visualizing biological activity and infiltration of the tumor. METHODS Using multimodality imaging, we investigated [18F]DPA-714, a radiotracer targeting the 18 kDa translocator protein (TSPO), [18F]FET PET, non-Gaussian diffusion MRI (apparent diffusion coefficient, kurtosis), and the S-index, a composite diffusion metric, to detect tumor infiltration in a human invasive glioma model. In vivo imaging findings were confirmed by autoradiography and immunofluorescence. RESULTS Increased tumor-to-contralateral [18F]DPA-714 uptake ratios (1.49 ± 0.11) were found starting 7 weeks after glioma cell implantation. TSPO-PET allowed visualization of glioma infiltration into the contralateral hemisphere 2 weeks earlier compared with the clinically relevant biomarker for biological glioma activity [18F]FET. Diffusion-weighted imaging (DWI), in particular kurtosis, was more sensitive than standard T2-weighted MRI to detect differences between the glioma-bearing and the contralateral hemisphere at 5 weeks. Immunofluorescence data reflect in vivo findings. Interestingly, labeling for tumoral and stromal TSPO indicates a predominant expression of TSPO by tumor cells. CONCLUSION These results suggest that advanced PET and MRI methods, such as [18F]DPA-714 and DWI, may be superior to standard imaging methods to visualize glioma growth and infiltration at an early stage.
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Affiliation(s)
- Hayet Pigeon
- UMR 1023, IMIV, Service Hospitalier Frédéric Joliot, CEA, Inserm, Université Paris Sud, CNRS, Université Paris-Saclay, Orsay, France
| | - Elodie A Pérès
- UMR 1023, IMIV, Service Hospitalier Frédéric Joliot, CEA, Inserm, Université Paris Sud, CNRS, Université Paris-Saclay, Orsay, France.,NeuroSpin, CEA/Université Paris-Saclay, Gif sur Yvette, France.,Normandie Université, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen, France
| | - Charles Truillet
- UMR 1023, IMIV, Service Hospitalier Frédéric Joliot, CEA, Inserm, Université Paris Sud, CNRS, Université Paris-Saclay, Orsay, France
| | - Benoit Jego
- UMR 1023, IMIV, Service Hospitalier Frédéric Joliot, CEA, Inserm, Université Paris Sud, CNRS, Université Paris-Saclay, Orsay, France
| | | | - Fabien Caillé
- UMR 1023, IMIV, Service Hospitalier Frédéric Joliot, CEA, Inserm, Université Paris Sud, CNRS, Université Paris-Saclay, Orsay, France
| | - Bastian Zinnhardt
- EIMI and Department of Nuclear Medicine, University Hospital Münster, Westfälische Wilhelms University Münster, Münster, Germany
| | - Andreas H Jacobs
- EIMI and Department of Nuclear Medicine, University Hospital Münster, Westfälische Wilhelms University Münster, Münster, Germany.,Department of Geriatrics, Johanniter Hospital, Evangelische Kliniken, Bonn, Germany
| | - Denis Le Bihan
- NeuroSpin, CEA/Université Paris-Saclay, Gif sur Yvette, France
| | - Alexandra Winkeler
- UMR 1023, IMIV, Service Hospitalier Frédéric Joliot, CEA, Inserm, Université Paris Sud, CNRS, Université Paris-Saclay, Orsay, France
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11
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Lopalco A, Cutrignelli A, Denora N, Perrone M, Iacobazzi RM, Fanizza E, Lopedota A, Depalo N, de Candia M, Franco M, Laquintana V. Delivery of Proapoptotic Agents in Glioma Cell Lines by TSPO Ligand-Dextran Nanogels. Int J Mol Sci 2018; 19:ijms19041155. [PMID: 29641449 PMCID: PMC5979576 DOI: 10.3390/ijms19041155] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/07/2018] [Accepted: 04/08/2018] [Indexed: 12/22/2022] Open
Abstract
Translocator protein 18-kDa (TSPO) is a versatile mitochondrial target for molecular imaging and therapy. Moreover, selective TSPO ligands have been widely investigated for diagnostic purposes and explored to target drug delivery systems directed to cancer cells overexpressing TSPO. Indeed, poly(d,l-lactic-co-glycolic acid (PLGA) polymers and nanocarriers decorated with TSPO ligands are capable of transporting TSPO ligands inside cancer cells, inducing survival inhibition in cancer cells and producing mitochondrial morphology modification. The aim of this work was to prepare nanogels (NGs) made with TSPO ligand dextran conjugates (TSPO-Dex) that are useful as potential delivery systems of two TSPO ligands as apoptotic agents. Synthesis and complete characterization of TSPO–dextran conjugates, an average molecular weights analysis, TSPO ligand release profiles, thermal behaviour and swelling studies were achieved. NG preparation, characterization and in vitro biological studies were also performed. The release of TSPO ligands released from dextran conjugates at 37 °C occurred in human serum at a faster rate than that detected in phosphate buffer. Cytotoxicity studies demonstrated that NGs produced from TSPO ligand–dextran conjugates induce survival inhibition in rat C6 glioma cell lines. Cellular uptake was also proven by fluorescence microscopy.
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Affiliation(s)
- Antonio Lopalco
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Via Orabona, St. 4, 70125 Bari, Italy.
| | - Annalisa Cutrignelli
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Via Orabona, St. 4, 70125 Bari, Italy.
| | - Nunzio Denora
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Via Orabona, St. 4, 70125 Bari, Italy.
- Institute for Physical and Chemical Processes (IPCF)-CNR, SS Bari, Via Orabona, St. 4, 70125 Bari, Italy.
| | - Mara Perrone
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Via Orabona, St. 4, 70125 Bari, Italy.
- Istituto tumori IRCCS "Giovanni Paolo II", Flacco, St. 65, 70124 Bari, Italy.
| | | | - Elisabetta Fanizza
- Institute for Physical and Chemical Processes (IPCF)-CNR, SS Bari, Via Orabona, St. 4, 70125 Bari, Italy.
- Department of Chemistry, University of Bari "Aldo Moro", 70125 Bari, Italy.
| | - Angela Lopedota
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Via Orabona, St. 4, 70125 Bari, Italy.
| | - Nicoletta Depalo
- Institute for Physical and Chemical Processes (IPCF)-CNR, SS Bari, Via Orabona, St. 4, 70125 Bari, Italy.
| | - Modesto de Candia
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Via Orabona, St. 4, 70125 Bari, Italy.
| | - Massimo Franco
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Via Orabona, St. 4, 70125 Bari, Italy.
| | - Valentino Laquintana
- Department of Pharmacy-Drug Sciences, University of Bari "Aldo Moro", Via Orabona, St. 4, 70125 Bari, Italy.
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12
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13
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Baez E, Guio-Vega GP, Echeverria V, Sandoval-Rueda DA, Barreto GE. 4'-Chlorodiazepam Protects Mitochondria in T98G Astrocyte Cell Line from Glucose Deprivation. Neurotox Res 2017; 32:163-171. [PMID: 28405935 DOI: 10.1007/s12640-017-9733-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/30/2017] [Accepted: 04/04/2017] [Indexed: 01/12/2023]
Abstract
The translocator protein (TSPO), formerly known as the peripheral-type benzodiazepine receptor (PBR), is considered an important regulator of steroidogenesis and a potential therapeutic target in neurological disorders. Previous evidence suggests that TSPO ligands can protect cells during injury and prevent apoptosis in central nervous system (CNS) cells. However, its actions on astrocytic cells under metabolic injury are not well understood. In this study, we explored whether 4'-chlorodiazepam (Ro5-4864), a TSPO ligand, might protect astrocyte mitochondria under glucose deprivation. Our results showed that 4'-chlorodiazepam preserved cell viability and reduced nuclear fragmentation in glucose-deprived cells. These effects were accompanied by a reduced production of free radicals and maintenance of mitochondrial functions in cells treated with 4'-chlorodiazepam. Finally, our findings suggest that TSPO might be involved in reducing oxidative stress by preserving mitochondrial functions in astrocytic cells exposed to glucose withdrawal.
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Affiliation(s)
- Eliana Baez
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia
| | - Gina Paola Guio-Vega
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia
| | | | - Daniel Andres Sandoval-Rueda
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia
| | - George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia. .,Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile.
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14
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Liu GJ, Middleton RJ, Kam WWY, Chin DY, Hatty CR, Chan RHY, Banati RB. Functional gains in energy and cell metabolism after TSPO gene insertion. Cell Cycle 2017; 16:436-447. [PMID: 28103132 PMCID: PMC5351937 DOI: 10.1080/15384101.2017.1281477] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Recent loss-of-function studies in tissue-specific as well as global Tspo (Translocator Protein 18 kDa) knockout mice have not confirmed its long assumed indispensability for the translocation of cholesterol across the mitochondrial inter-membrane space, a rate-limiting step in steroid biosynthesis. Instead, recent studies in global Tspo knockout mice indicate that TSPO may play a more fundamental role in cellular bioenergetics, which may include the indirect down-stream regulation of transport or metabolic functions. To examine whether overexpression of the TSPO protein alters the cellular bioenergetic profile, Jurkat cells with low to absent endogenous expression were transfected with a TSPO construct to create a stable cell line with de novo expression of exogenous TSPO protein. Expression of TSPO was confirmed by RT-qPCR, radioligand binding with [3H]PK11195 and immunocytochemistry with a TSPO antibody. We demonstrate that TSPO gene insertion causes increased transcription of genes involved in the mitochondrial electron transport chain. Furthermore, TSPO insertion increased mitochondrial ATP production as well as cell excitability, reflected in a decrease in patch clamp recorded rectified K channel currents. These functional changes were accompanied by an increase in cell proliferation and motility, which were inhibited by PK11195, a selective ligand for TSPO. We suggest that TSPO may serve a range of functions that can be viewed as downstream regulatory effects of its primary, evolutionary conserved role in cell metabolism and energy production.
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Affiliation(s)
- Guo-Jun Liu
- a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.,b Faculty of Health Science and Brain and Mind Centre, University of Sydney , NSW , Australia
| | - Ryan J Middleton
- a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia
| | - Winnie Wai-Ying Kam
- a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.,c Department of Health Technology and Informatics , Hong Kong Polytechnic University , Hung Hom, Hong Kong , China
| | - David Y Chin
- d NCRIS Biologics Facility, Australian Institute for Bioengineering and Nanotechnology, University of Queensland , QLD , Australia
| | - Claire R Hatty
- a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.,b Faculty of Health Science and Brain and Mind Centre, University of Sydney , NSW , Australia
| | - Ronald H Y Chan
- a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.,b Faculty of Health Science and Brain and Mind Centre, University of Sydney , NSW , Australia
| | - Richard B Banati
- a Australian Nuclear Science and Technology Organisation , Lucas Heights , NSW , Australia.,b Faculty of Health Science and Brain and Mind Centre, University of Sydney , NSW , Australia
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15
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Derivatives of the pyrazolo[1,5-a]pyrimidine acetamide DPA-713 as translocator protein (TSPO) ligands and pro-apoptotic agents in human glioblastoma. Eur J Pharm Sci 2016; 96:186-192. [PMID: 27658888 DOI: 10.1016/j.ejps.2016.09.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 09/09/2016] [Accepted: 09/17/2016] [Indexed: 12/13/2022]
Abstract
The 18kDa translocator protein (TSPO) is a target for novel glioblastoma therapies due to its upregulation in this cancer and relatively low levels of expression in the healthy cortex. The pyrazolo[1,5-a]pyrimidine acetamides, exemplified by DPA-713 and DPA-714, are a class of high affinity TSPO ligands with selectivity over the central benzodiazepine receptor. In this study we have explored the potential anti-glioblastoma activity of a library of DPA-713 and DPA-714 analogues, and investigated the effect of amending the alkyl ether chain on TSPO affinity and functional potential. All ligands demonstrated nanomolar affinity for TSPO, but showed diverse functional activity, for example DPA-713 and DPA-714 did not affect the proliferation or viability of human T98G glioblastoma cells, while the hexyl ether and benzyl ether derivatives decreased proliferation of T98G cells without affecting proliferation in human fetal glial SVGp12 cells. These ligands also induced apoptosis and dissipated T98G mitochondrial membrane potential. This suggests that the nature of the alkyl ether chain of pyrazolo[1,5-a]pyrimidine acetamides has little influence on TSPO affinity but is important for functional activity of this class of TSPO ligands.
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16
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Mercado AT, Yeh JM, Chin TY, Chen WS, Chen-Yang YW, Chen CY. The effect of chemically modified electrospun silica nanofiber on the mRNA and miRNA expression profile of neural stem cell differentiation. J Biomed Mater Res A 2016; 104:2730-43. [DOI: 10.1002/jbm.a.35819] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Accepted: 06/21/2016] [Indexed: 01/30/2023]
Affiliation(s)
- Augustus T. Mercado
- Department of Bioscience Technology; Chung Yuan Christian University; Chung-Li 32023 Taiwan
- Department of Chemistry; Chung Yuan Christian University; Chung-Li 32023 Taiwan
| | - Jui-Ming Yeh
- Department of Chemistry; Chung Yuan Christian University; Chung-Li 32023 Taiwan
- Center for Biomedical Technology, Chung Yuan Christian University; Chung-Li 32023 Taiwan
| | - Ting Yu Chin
- Department of Bioscience Technology; Chung Yuan Christian University; Chung-Li 32023 Taiwan
- Center for Biomedical Technology, Chung Yuan Christian University; Chung-Li 32023 Taiwan
| | - Wen Shuo Chen
- Department of Chemistry; Chung Yuan Christian University; Chung-Li 32023 Taiwan
- Center for Biomedical Technology, Chung Yuan Christian University; Chung-Li 32023 Taiwan
| | - Yui Whei Chen-Yang
- Department of Chemistry; Chung Yuan Christian University; Chung-Li 32023 Taiwan
- Center for Biomedical Technology, Chung Yuan Christian University; Chung-Li 32023 Taiwan
| | - Chung-Yung Chen
- Department of Bioscience Technology; Chung Yuan Christian University; Chung-Li 32023 Taiwan
- Center for Biomedical Technology, Chung Yuan Christian University; Chung-Li 32023 Taiwan
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17
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TSPO Ligand-Methotrexate Prodrug Conjugates: Design, Synthesis, and Biological Evaluation. Int J Mol Sci 2016; 17:ijms17060967. [PMID: 27322261 PMCID: PMC4926499 DOI: 10.3390/ijms17060967] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/06/2016] [Accepted: 06/13/2016] [Indexed: 12/28/2022] Open
Abstract
The 18-kDa translocator protein (TSPO) is a potential mitochondrial target for drug delivery to tumors overexpressing TSPO, including brain cancers, and selective TSPO ligands have been successfully used to selectively deliver drugs into the target. Methotrexate (MTX) is an anticancer drug of choice for the treatment of several cancers, but its permeability through the blood brain barrier (BBB) is poor, making it unsuitable for the treatment of brain tumors. Therefore, in this study, MTX was selected to achieve two TSPO ligand-MTX conjugates (TSPO ligand α-MTX and TSPO ligand γ-MTX), potentially useful for the treatment of TSPO-rich cancers, including brain tumors. In this work, we have presented the synthesis, the physicochemical characterizations, as well as the in vitro stabilities of the new TSPO ligand-MTX conjugates. The binding affinity for TSPO and the selectivity versus central-type benzodiazepine receptor (CBR) was also investigated. The cytotoxicity of prepared conjugates was evaluated on MTX-sensitive human and rat glioma cell lines overexpressing TSPO. The estimated coefficients of lipophilicity and the stability studies of the conjugates confirm that the synthesized molecules are stable enough in buffer solution at pH 7.4, as well in physiological medium, and show an increased lipophilicity compared to the MTX, compatible with a likely ability to cross the blood brain barrier. The latter feature of two TSPO ligand-MTX conjugates was also confirmed by in vitro permeability studies conducted on Madin-Darby canine kidney cells transfected with the human MDR1 gene (MDCK-MDR1) monolayers. TSPO ligand-MTX conjugates have shown to possess a high binding affinity for TSPO, with IC50 values ranging from 7.2 to 40.3 nM, and exhibited marked toxicity against glioma cells overexpressing TSPO, in comparison with the parent drug MTX.
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18
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Mirzaei N, Tang SP, Ashworth S, Coello C, Plisson C, Passchier J, Selvaraj V, Tyacke RJ, Nutt DJ, Sastre M. In vivo imaging of microglial activation by positron emission tomography with [(11)C]PBR28 in the 5XFAD model of Alzheimer's disease. Glia 2016; 64:993-1006. [PMID: 26959396 DOI: 10.1002/glia.22978] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 02/08/2016] [Indexed: 11/05/2022]
Abstract
Microglial activation has been linked with deficits in neuronal function and synaptic plasticity in Alzheimer's disease (AD). The mitochondrial translocator protein (TSPO) is known to be upregulated in reactive microglia. Accurate visualization and quantification of microglial density by PET imaging using the TSPO tracer [(11)C]-R-PK11195 has been challenging due to the limitations of the ligand. In this study, it was aimed to evaluate the new TSPO tracer [(11)C]PBR28 as a marker for microglial activation in the 5XFAD transgenic mouse model of AD. Dynamic PET scans were acquired following intravenous administration of [(11)C]PBR28 in 6-month-old 5XFAD mice and in wild-type controls. Autoradiography with [(3)H]PBR28 was carried out in the same brains to further confirm the distribution of the radioligand. In addition, immunohistochemistry was performed on adjacent brain sections of the same mice to evaluate the co-localization of TSPO with microglia. PET imaging revealed that brain uptake of [(11)C]PBR28 in 5XFAD mice was increased compared with control mice. Moreover, binding of [(3)H]PBR28, measured by autoradiography, was enriched in cortical and hippocampal brain regions, coinciding with the positive staining of the microglial marker Iba-1 and amyloid deposits in the same areas. Furthermore, double-staining using antibodies against TSPO demonstrated co-localization of TSPO with microglia and not with astrocytes in 5XFAD mice and human post-mortem AD brains. The data provided support of the suitability of [(11)C]PBR28 as a tool for in vivo monitoring of microglial activation and assessment of treatment response in future studies using animal models of AD.
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Affiliation(s)
- Nazanin Mirzaei
- Division of Brain Sciences, Imperial College London, Du Cane Road, London, W12 0NN, United Kingdom
| | - Sac Pham Tang
- Imanova Limited, Du Cane Road, London, W12 0NN, United Kingdom
| | - Sharon Ashworth
- Imanova Limited, Du Cane Road, London, W12 0NN, United Kingdom
| | | | | | - Jan Passchier
- Imanova Limited, Du Cane Road, London, W12 0NN, United Kingdom
| | - Vimal Selvaraj
- Department of Animal Science, Cornell University, Ithaca, New York
| | - Robin J Tyacke
- Division of Brain Sciences, Imperial College London, Du Cane Road, London, W12 0NN, United Kingdom
| | - David J Nutt
- Division of Brain Sciences, Imperial College London, Du Cane Road, London, W12 0NN, United Kingdom
| | - Magdalena Sastre
- Division of Brain Sciences, Imperial College London, Du Cane Road, London, W12 0NN, United Kingdom
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19
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Morin D, Musman J, Pons S, Berdeaux A, Ghaleh B. Mitochondrial translocator protein (TSPO): From physiology to cardioprotection. Biochem Pharmacol 2015; 105:1-13. [PMID: 26688086 DOI: 10.1016/j.bcp.2015.12.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 12/04/2015] [Indexed: 01/08/2023]
Abstract
The mitochondrial translocator protein (TSPO) is a high affinity cholesterol binding protein which is primarily located in the outer mitochondrial membrane where it has been shown to interact with proteins implicated in mitochondrial permeability transition pore (mPTP) formation. TSPO is found in different species and is expressed at high levels in tissues that synthesize steroids but is also present in other peripheral tissues especially in the heart. TSPO has been involved in the import of cholesterol into mitochondria, a key step in steroidogenesis. This constitutes the main established function of the protein which was recently challenged by genetic studies. TSPO has also been associated directly or indirectly with a wide range of cellular functions such as apoptosis, cell proliferation, differentiation, regulation of mitochondrial function or porphyrin transport. In the heart the role of TSPO remains undefined but a growing body of evidence suggests that TSPO plays a critical role in regulating physiological cardiac function and that TSPO ligands may represent interesting drugs to protect the heart under pathological conditions. This article briefly reviews current knowledge regarding TSPO and discusses its role in the cardiovascular system under physiological and pathologic conditions. More particularly, it provides evidence that TSPO can represent an alternative strategy to develop new pharmacological agents to protect the myocardium against ischemia-reperfusion injury.
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Affiliation(s)
- Didier Morin
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Julien Musman
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Sandrine Pons
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Alain Berdeaux
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
| | - Bijan Ghaleh
- INSERM U955, Équipe 3, Créteil, France; Université Paris-Est, UMR_S955, DHU A-TVB, UPEC, Créteil, France.
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20
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Azarashvili T, Krestinina O, Baburina Y, Odinokova I, Grachev D, Papadopoulos V, Akatov V, Lemasters JJ, Reiser G. Combined effect of G3139 and TSPO ligands on Ca(2+)-induced permeability transition in rat brain mitochondria. Arch Biochem Biophys 2015; 587:70-7. [PMID: 26498031 DOI: 10.1016/j.abb.2015.10.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 10/15/2015] [Accepted: 10/16/2015] [Indexed: 02/06/2023]
Abstract
Permeability of the mitochondrial outer membrane is determined by the activity of voltage-dependent anion channels (VDAC) which are regulated by many factors and proteins. One of the main partner-regulator of VDAC is the 18 kDa translocator protein (TSPO), whose role in the regulation of membrane permeability is not completely understood. We show that TSPO ligands, 1 μM PPIX and PK11195 at concentrations of 50 μM, accelerate opening of permeability transition pores (mPTP) in Ca(2+)-overloaded rat brain mitochondria (RBM). By contrast, PK11195 at 100 nM and anti-TSPO antibodies suppressed pore opening. Participation of VDAC in these processes was demonstrated by blocking VDAC with G3139, an 18-mer phosphorothioate oligonucleotides, which sensitized mitochondria to Ca(2+)-induced mPTP opening. Despite the inhibitory effect of 100 nM PK11195 and anti-TSPO antibodies alone, their combination with G3139 considerably stimulated the mPTP opening. Thus, 100 nM PK11195 and anti-TSPO antibody can modify permeability of the VDAC channel and mPTP. When VDAC channels are closed and TSPO is blocked, permeability of the VDAC for calcium seems to be the highest, which leads to accelerated pore opening.
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Affiliation(s)
- T Azarashvili
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia.
| | - O Krestinina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia.
| | - Yu Baburina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia.
| | - I Odinokova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia.
| | - D Grachev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia.
| | - V Papadopoulos
- The Research Institute of the McGill University Health Center, and Departments of Medicine, Biochemistry, Pharmacology and Therapeutics, McGill University, 2155 Guy Street, Montreal, Que., H3H 2R9, Canada.
| | - V Akatov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia.
| | - J J Lemasters
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region, 142290, Russia; Departments of Drug Discovery & Biomedical Sciences and Biochemistry & Molecular Biology, Medical University of South Carolina, DD504 Drug Discovery Bldg., 70 President St., MSC 140, Charleston, SC, 29425, USA.
| | - G Reiser
- Institut für Neurobiochemie, Otto-von-Guericke-Universität Magdeburg, Medizinische Fakultät, Leipziger Str. 44, 39120, Magdeburg, Germany.
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Abstract
The translocator protein (TSPO) is an 18-kDa five-transmembrane protein, which is primarily found in the outer mitochondrial membrane. Levels of this protein are up-regulated in the most aggressive and common glioma, glioblastoma multiforme (GM). Levels of TSPO also correlate with GM clinical outcome, suggesting that TSPO may be a novel GM diagnostic imaging agent. Therapeutically, targeting the TSPO may provide a mechanism to abrogate the apoptotic-resistant, invasive and aggressive nature of GM and may also provide a way of targeting other anti-cancer treatments to GM sites. This review highlights recent progress in research on TSPO-based diagnostic imaging and therapeutics for GM.
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Lin R, Angelin A, Da Settimo F, Martini C, Taliani S, Zhu S, Wallace DC. Genetic analysis of dTSPO, an outer mitochondrial membrane protein, reveals its functions in apoptosis, longevity, and Ab42-induced neurodegeneration. Aging Cell 2014; 13:507-18. [PMID: 24977274 PMCID: PMC4076708 DOI: 10.1111/acel.12200] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The outer mitochondrial membrane (OMM) protein, the translocator protein 18 kDa (TSPO), formerly named the peripheral benzodiazepine receptor (PBR), has been proposed to participate in the pathogenesis of neurodegenerative diseases. To clarify the TSPO function, we identified the Drosophila homolog, CG2789/dTSPO, and studied the effects of its inactivation by P-element insertion, RNAi knockdown, and inhibition by ligands (PK11195, Ro5-4864). Inhibition of dTSPO inhibited wing disk apoptosis in response to γ-irradiation or H2O2 exposure, as well as extended male fly lifespan and inhibited Aβ42-induced neurodegeneration in association with decreased caspase activation. Therefore, dTSPO is an essential mediator of apoptosis in Drosophila and plays a central role in controlling longevity and neurodegenerative disease, making it a promising drug target.
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Affiliation(s)
- Ran Lin
- Department of Physiology and Pathophysiology School of Basic Medical Sciences Health Science Center Peking University Beijing 100191China
- Center for Mitochondrial and Epigenomic Medicine Children's Hospital of Philadelphia Research Institute Philadelphia PA 19104USA
| | - Alessia Angelin
- Center for Mitochondrial and Epigenomic Medicine Children's Hospital of Philadelphia Research Institute Philadelphia PA 19104USA
| | | | - Claudia Martini
- Dipartimento di Farmacia Università di Pisa via Bonanno 656126Pisa Italy
| | - Sabrina Taliani
- Dipartimento di Farmacia Università di Pisa via Bonanno 656126Pisa Italy
| | - Shigong Zhu
- Department of Physiology and Pathophysiology School of Basic Medical Sciences Health Science Center Peking University Beijing 100191China
| | - Douglas C. Wallace
- Center for Mitochondrial and Epigenomic Medicine Children's Hospital of Philadelphia Research Institute Philadelphia PA 19104USA
- Department of Pathology and Laboratory Medicine Perelman School of Medicine University of Pennsylvania Philadelphia PA 19104USA
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23
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Zhou X, He B, Zhu Z, He X, Zheng C, Xu J, Jiang L, Gu L, Zhu J, Zhu Q, Liu X. Etifoxine provides benefits in nerve repair with acellular nerve grafts. Muscle Nerve 2014; 50:235-43. [PMID: 24273088 DOI: 10.1002/mus.24131] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 11/13/2013] [Accepted: 11/19/2013] [Indexed: 01/31/2023]
Affiliation(s)
- Xiang Zhou
- Department of Microsurgery and Orthopedic Trauma; the First Affiliated Hospital of Sun Yat-sen University; Guangzhou 510080 China
| | - Bo He
- Department of Microsurgery and Orthopedic Trauma; the First Affiliated Hospital of Sun Yat-sen University; Guangzhou 510080 China
| | - Zhaowei Zhu
- Department of Microsurgery and Orthopedic Trauma; the First Affiliated Hospital of Sun Yat-sen University; Guangzhou 510080 China
| | - Xinhua He
- Department of Physiology; Medical College of Shangtou University; Shantou China
| | - Canbin Zheng
- Department of Microsurgery and Orthopedic Trauma; the First Affiliated Hospital of Sun Yat-sen University; Guangzhou 510080 China
| | - Jian Xu
- Department of Reproductive Medicine Center; First Affiliated Hospital of Sun Yat-sen University; Guangzhou China
| | - Li Jiang
- Department of Microsurgery and Orthopedic Trauma; the First Affiliated Hospital of Sun Yat-sen University; Guangzhou 510080 China
| | - Liqiang Gu
- Department of Microsurgery and Orthopedic Trauma; the First Affiliated Hospital of Sun Yat-sen University; Guangzhou 510080 China
| | - Jiakai Zhu
- Department of Microsurgery and Orthopedic Trauma; the First Affiliated Hospital of Sun Yat-sen University; Guangzhou 510080 China
| | - Qingtang Zhu
- Department of Microsurgery and Orthopedic Trauma; the First Affiliated Hospital of Sun Yat-sen University; Guangzhou 510080 China
| | - Xiaolin Liu
- Department of Microsurgery and Orthopedic Trauma; the First Affiliated Hospital of Sun Yat-sen University; Guangzhou 510080 China
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Piccinonna S, Margiotta N, Denora N, Iacobazzi RM, Pacifico C, Trapani G, Natile G. A model radiopharmaceutical agent targeted to translocator protein 18 kDa (TSPO). Dalton Trans 2014; 42:10112-5. [PMID: 23752769 DOI: 10.1039/c3dt51152a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A stable Re complex containing an imidazopyridine ligand with a high affinity for TSPO has been synthesized as a model for new (99m)Tc or (188/186)Re-based radiopharmaceuticals to be used in SPECT diagnosis or in therapy, respectively. The new complex fac-[ReBr(CO)3(TZ6)], structurally characterized, showed high affinity (nanomolar concentration) for the target protein.
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Affiliation(s)
- Sara Piccinonna
- Dipartimento di Chimica, Università degli Studi di Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy
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Laquintana V, Denora N, Lopalco A, Lopedota A, Cutrignelli A, Lasorsa FM, Agostino G, Franco M. Translocator Protein Ligand–PLGA Conjugated Nanoparticles for 5-Fluorouracil Delivery to Glioma Cancer Cells. Mol Pharm 2014; 11:859-71. [DOI: 10.1021/mp400536z] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Valentino Laquintana
- Dipartimento
di Farmacia-Scienze del Farmaco, Università degli Studi di Bari “Aldo Moro”, via Orabona 4, 70125 Bari, Italy
| | - Nunzio Denora
- Dipartimento
di Farmacia-Scienze del Farmaco, Università degli Studi di Bari “Aldo Moro”, via Orabona 4, 70125 Bari, Italy
| | - Antonio Lopalco
- Dipartimento
di Farmacia-Scienze del Farmaco, Università degli Studi di Bari “Aldo Moro”, via Orabona 4, 70125 Bari, Italy
| | - Angela Lopedota
- Dipartimento
di Farmacia-Scienze del Farmaco, Università degli Studi di Bari “Aldo Moro”, via Orabona 4, 70125 Bari, Italy
| | - Annalisa Cutrignelli
- Dipartimento
di Farmacia-Scienze del Farmaco, Università degli Studi di Bari “Aldo Moro”, via Orabona 4, 70125 Bari, Italy
| | | | - Giulia Agostino
- Dipartimento
di Bioscienze, Biotecnologie e Biofarmaceutica, Università degli Studi di Bari “Aldo Moro”, via Orabona 4, 70125 Bari, Italy
| | - Massimo Franco
- Dipartimento
di Farmacia-Scienze del Farmaco, Università degli Studi di Bari “Aldo Moro”, via Orabona 4, 70125 Bari, Italy
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Karlstetter M, Nothdurfter C, Aslanidis A, Moeller K, Horn F, Scholz R, Neumann H, Weber BHF, Rupprecht R, Langmann T. Translocator protein (18 kDa) (TSPO) is expressed in reactive retinal microglia and modulates microglial inflammation and phagocytosis. J Neuroinflammation 2014; 11:3. [PMID: 24397957 PMCID: PMC3895821 DOI: 10.1186/1742-2094-11-3] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 12/23/2013] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The translocator protein (18 kDa) (TSPO) is a mitochondrial protein expressed on reactive glial cells and a biomarker for gliosis in the brain. TSPO ligands have been shown to reduce neuroinflammation in several mouse models of neurodegeneration. Here, we analyzed TSPO expression in mouse and human retinal microglia and studied the effects of the TSPO ligand XBD173 on microglial functions. METHODS TSPO protein analyses were performed in retinoschisin-deficient mouse retinas and human retinas. Lipopolysaccharide (LPS)-challenged BV-2 microglial cells were treated with XBD173 and TSPO shRNAs in vitro and pro-inflammatory markers were determined by qRT-PCR. The migration potential of microglia was determined with wound healing assays and the proliferation was studied with Fluorescence Activated Cell Sorting (FACS) analysis. Microglial neurotoxicity was estimated by nitrite measurement and quantification of caspase 3/7 levels in 661 W photoreceptors cultured in the presence of microglia-conditioned medium. The effects of XBD173 on filopodia formation and phagocytosis were analyzed in BV-2 cells and human induced pluripotent stem (iPS) cell-derived microglia (iPSdM). The morphology of microglia was quantified in mouse retinal explants treated with XBD173. RESULTS TSPO was strongly up-regulated in microglial cells of the dystrophic mouse retina and also co-localized with microglia in human retinas. Constitutive TSPO expression was high in the early postnatal Day 3 mouse retina and declined to low levels in the adult tissue. TSPO mRNA and protein were also strongly induced in LPS-challenged BV-2 microglia while the TSPO ligand XBD173 efficiently suppressed transcription of the pro-inflammatory marker genes chemokine (C-C motif) ligand 2 (CCL2), interleukin 6 (IL6) and inducible nitric oxide (NO)-synthase (iNOS). Moreover, treatment with XBD173 significantly reduced the migratory capacity and proliferation of microglia, their level of NO secretion and their neurotoxic activity on 661 W photoreceptor cells. Furthermore, XBD173 treatment of murine and human microglial cells promoted the formation of filopodia and increased their phagocytic capacity to ingest latex beads or photoreceptor debris. Finally, treatment with XBD173 reversed the amoeboid alerted phenotype of microglial cells in explanted organotypic mouse retinal cultures after challenge with LPS. CONCLUSIONS These findings suggest that TSPO is highly expressed in reactive retinal microglia and a promising target to control microglial reactivity during retinal degeneration.
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Affiliation(s)
- Marcus Karlstetter
- Department of Ophthalmology, University of Cologne, D-50931 Cologne, Germany
| | - Caroline Nothdurfter
- Department of Psychiatry and Psychotherapy, University of Regensburg, D-93053 Regensburg, Germany
| | - Alexander Aslanidis
- Department of Ophthalmology, University of Cologne, D-50931 Cologne, Germany
| | - Katharina Moeller
- Department of Ophthalmology, University of Cologne, D-50931 Cologne, Germany
| | - Felicitas Horn
- Department of Ophthalmology, University of Cologne, D-50931 Cologne, Germany
| | - Rebecca Scholz
- Department of Ophthalmology, University of Cologne, D-50931 Cologne, Germany
| | - Harald Neumann
- Institute of Reconstructive Neurobiology, University of Bonn, D-53127 Bonn, Germany
| | - Bernhard H F Weber
- Institute of Human Genetics, University of Regensburg, D-93053 Regensburg, Germany
| | - Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, University of Regensburg, D-93053 Regensburg, Germany
| | - Thomas Langmann
- Department of Ophthalmology, University of Cologne, D-50931 Cologne, Germany
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Awde AR, Boisgard R, Thézé B, Dubois A, Zheng J, Dollé F, Jacobs AH, Tavitian B, Winkeler A. The translocator protein radioligand 18F-DPA-714 monitors antitumor effect of erufosine in a rat 9L intracranial glioma model. J Nucl Med 2013; 54:2125-31. [PMID: 24212976 DOI: 10.2967/jnumed.112.118794] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED On the one hand, the translocator protein (TSPO) radioligand N,N-diethyl-2-(2-(4-(2-(18)F-fluoroethoxy)phenyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-yl)acetamide ((18)F-DPA-714) has been suggested to serve as an alternative radiotracer to image human glioma, and on the other hand the alkylphosphocholine erufosine (ErPC3) has been reported to induce apoptosis in otherwise highly apoptosis-resistant glioma cell lines. The induction of apoptosis by ErPC3 requires TSPO, a mitochondrial membrane protein highly expressed in malignant gliomas. In this preclinical study, we monitored the effect of ErPC3 treatment in vivo using (18)F-DPA-714 PET. METHODS In vitro studies investigated the antitumor effect of ErPC3 in 9L rat gliosarcoma cells. In vivo, glioma-bearing rats were imaged with (18)F-DPA-714 for the time of treatment. RESULTS A significant decrease in 9L cell proliferation and viability and a significant increase in apoptosis and caspase-3 activation were demonstrated on ErPC3 treatment in cell culture. In the rat model, ErPC3 administration resulted in significant changes in (18)F-DPA-714 tumor uptake over the course of the treatment. Immunohistochemistry revealed reduced tumor volume and increased cell death in ErPC3-treated animals accompanied by infiltration of the tumor core by CD11b-positive microglia/macrophages and glial fibrillary acidic protein-positive astrocytes. CONCLUSION Our findings demonstrate a potent antitumor effect of ErPC3 in vitro, in vivo, and ex vivo. PET imaging of TSPO expression using (18)F-DPA-714 allows effective monitoring and quantification of disease progression and response to ErPC3 therapy in intracranial 9L gliomas.
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The 18-kDa translocator protein (TSPO) disrupts mammary epithelial morphogenesis and promotes breast cancer cell migration. PLoS One 2013; 8:e71258. [PMID: 23967175 PMCID: PMC3743866 DOI: 10.1371/journal.pone.0071258] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 06/27/2013] [Indexed: 12/04/2022] Open
Abstract
Mitochondria play important roles in cancer progression and have emerged as viable targets for cancer therapy. Increasing levels of the outer mitochondrial membrane protein, 18-kDa translocator protein (TSPO), are associated with advancing breast cancer stage. In particular, higher TSPO levels are found in estrogen receptor (ER)-negative breast tumors, compared with ER-positive tumors. In this study, we sought to define the roles of TSPO in the acquisition of breast cancer malignancy. Using a three-dimensional Matrigel culture system, we determined the impact of elevated TSPO levels on mammary epithelial morphogenesis. Our studies demonstrate that stable overexpression of TSPO in mammary epithelial MCF10A acini drives proliferation and provides partial resistance to luminal apoptosis, resulting in enlarged acinar structures with partially filled lumen that resemble early stage breast lesions leading to breast cancer. In breast cancer cell lines, TSPO silencing or TSPO overexpression significantly altered the migratory activity. In addition, we found that combination treatment with the TSPO ligands (PK 11195 or Ro5-4864) and lonidamine, a clinical phase II drug targeting mitochondria, decreased viability of ER-negative breast cancer cell lines. Taken together, these data demonstrate that increases in TSPO levels at different stages of breast cancer progression results in the acquisition of distinct properties associated with malignancy. Furthermore, targeting TSPO, particularly in combination with other mitochondria-targeting agents, may prove useful for the treatment of ER-negative breast cancer.
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The 18 kDa translocator protein influences angiogenesis, as well as aggressiveness, adhesion, migration, and proliferation of glioblastoma cells. Pharmacogenet Genomics 2012; 22:538-50. [PMID: 22547081 DOI: 10.1097/fpc.0b013e3283539cdc] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND It is known that the mitochondrial 18 kDa translocator protein (TSPO) is present in almost all peripheral tissues and also in glial cells in the brain. TSPO levels are typically enhanced in correlation with tumorigenesis of cancer cells including glioblastoma. Relevant for angiogenesis, TSPO is also present in almost all cells of the cardiovascular system. METHODS We studied the effect of TSPO knockdown by siRNA on various aspects of tumor growth of U118MG glioblastoma cells in two in-vivo models: a nude mouse model with intracerebral implants of U118MG glioblastoma cells and implantation of U118MG glioblastoma cells on the chorionallantoic membrane (CAM) of chicken embryos. In vitro, we further assayed the influence of TSPO on the invasive potential of U118MG cells. RESULTS TSPO knockdown increased tumor growth in both in-vivo models compared with the scrambled siRNA control. Angiogenesis was also increased by TSPO knockdown as determined by a CAM assay. TSPO knockdown led to a decrease in adhesion to the proteins of the extracellular matrix, including fibronectin, collagen I, collagen IV, laminin I, and fibrinogen. TSPO knockdown also led to an enhancement in the migratory capability of U118MG cells, as determined in a modified Boyden chamber. Application of the TSPO ligand 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide (PK 11195) at a concentration of 25 µmol/l in the in-vitro models yielded results similar to those obtained on TSPO knockdown. We found no effects of PK 11195 on TSPO protein expression. Interestingly, at low nmol/l concentrations (around 1 nmol/l), PK 11195 enhanced adhesion to collagen I, suggesting a bimodal concentration effect of PK 11195. CONCLUSION Intact TSPO appears to be able to counteract the invasive and angiogenic characteristics related to the aggressiveness of U118MG glioblastoma cells in vivo and in vitro.
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Rupprecht R, Papadopoulos V, Rammes G, Baghai TC, Fan J, Akula N, Groyer G, Adams D, Schumacher M. Translocator protein (18 kDa) (TSPO) as a therapeutic target for neurological and psychiatric disorders. Nat Rev Drug Discov 2011; 9:971-88. [PMID: 21119734 DOI: 10.1038/nrd3295] [Citation(s) in RCA: 721] [Impact Index Per Article: 55.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The translocator protein (18 kDa) (TSPO) is localized primarily in the outer mitochondrial membrane of steroid-synthesizing cells, including those in the central and peripheral nervous system. One of its main functions is the transport of the substrate cholesterol into mitochondria, a prerequisite for steroid synthesis. TSPO expression may constitute a biomarker of brain inflammation and reactive gliosis that could be monitored by using TSPO ligands as neuroimaging agents. Moreover, initial clinical trials have indicated that TSPO ligands might be valuable in the treatment of neurological and psychiatric disorders. This Review focuses on the biology and pathophysiology of TSPO and the potential of currently available TSPO ligands for the diagnosis and treatment of neurological and psychiatric disorders.
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Affiliation(s)
- Rainer Rupprecht
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians University, Nussbaumstrasse 7, 80336 Munich, Germany.
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Rappa G, Anzanello F, Lorico A. Imatinib mesylate enhances the malignant behavior of human breast carcinoma cells. Cancer Chemother Pharmacol 2010; 67:919-26. [PMID: 20596710 DOI: 10.1007/s00280-010-1394-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Accepted: 06/20/2010] [Indexed: 01/05/2023]
Abstract
PURPOSE Imatinib mesylate (Imatinib), clinically employed for chronic myeloid leukemia and gastrointestinal stromal tumors, is a selective inhibitor of the tyrosine kinases, c-abl, c-kit and PDGFRs. Due to the frequent expression of these genes in breast cancer cells, the clinical efficacy of Imatinib has recently been investigated in patients with advanced and metastatic breast cancer. Here, we have studied the effects of Imatinib on human MA-11 breast carcinoma cells, expressing both c-abl and PDGFRbeta, in vitro and in mouse xenografts. METHODS The effects of Imatinib mesylate on the human MA-11 breast carcinoma cell line were studied in vitro and in xenografts. RESULTS Daily intraperitoneal treatment with 60 mg/kg Imatinib for 9 days of athymic nude mice pre-implanted subcutaneously with MA-11 cells did not result in an anti-tumor effect, but rather increased the take rate of 3 × 10(4) cells from 30.8 to 84.6% and caused the appearance of large abdominal masses in 30% of mice. To investigate the mechanism(s) of the observed effects of Imatinib on MA-11 tumors, we exposed the cells in vitro to Imatinib for 9 days. The surviving population, expanded in culture, showed increased motility and over-expressed a set of genes associated with aggressive behavior. Also, several genes belonging to the Wnt and the MAPK pathway were differentially expressed. In promoter activation assays, Imatinib increased the promoter activity driven by both Wnt and MAPK/ERK-1/2. CONCLUSIONS Our data suggest caution in the clinical use of Imatinib in breast cancer patients; the comparison of Imatinib-surviving breast cancer cells with parental cells may help define the regulatory pathways involved in the increased malignancy of residual tumor cells that survive therapy, ultimately providing important therapeutic targets.
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Affiliation(s)
- Germana Rappa
- Department of Drug Development, Nevada Cancer Institute, One Breakthrough Way, Las Vegas, NV 89135, USA
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Nagler R, Ben-Izhak O, Savulescu D, Krayzler E, Akrish S, Leschiner S, Otradnov I, Zeno S, Veenman L, Gavish M. Oral cancer, cigarette smoke and mitochondrial 18kDa translocator protein (TSPO) - In vitro, in vivo, salivary analysis. Biochim Biophys Acta Mol Basis Dis 2010; 1802:454-61. [PMID: 20085808 DOI: 10.1016/j.bbadis.2010.01.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 12/24/2009] [Accepted: 01/07/2010] [Indexed: 12/31/2022]
Abstract
Oral cancer features high rates of mortality and morbidity, and is in dire need for new approaches. In the present study we analyzed 18 kDa translocator protein (TSPO) expression in oral (tongue) cancer tumors by immunohistochemistry. We also assayed TSPO binding in human tongue cancer cell lines and in the cellular fraction of saliva from tongue cancer patients, heavy cigarette smokers, and non-smoking healthy people as controls. Concurrently, TSPO protein levels, cell viability, mitochondrial membrane potential (Deltapsi(m)), and general protein levels were analyzed. TSPO expression could be significantly enhanced in oral cancer tumors, compared to unaffected adjacent tissue. We also found that five-year survival probability dropped from 65% in patients with TSPO negative tumors to 7% in patients with highly expressed TSPO (p<0.001). TSPO binding capacity was also pronounced in the human oral cancer cell lines SCC-25 and SCC-15 (3133+/-643 fmol/mg protein and 6956+/-549 fmol/mg protein, respectively). Binding decreased by 56% and 72%, in the SCC-25 and SCC-15 cell lines, respectively (p<0.05) following CS exposure in cell culture. In the cellular fraction of saliva of heavy smokers TSPO binding was lower than in non-smokers (by 53%, p<0.05). Also the cellular fraction of saliva exposed to CS in vitro showed decreased TSPO binding compared to unexposed saliva (by 30%, p<0.001). Interestingly, oral cancer patients also displayed significantly lower TSPO binding in the cellular fraction of saliva compared to healthy controls (by 40%, p<0.01). Our results suggest that low TSPO binding found in the cellular fraction of saliva may depend on genetic background as well as result from exposure to CS. We suggest that this may be related to a predisposition for occurrence of oral cancer.
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Affiliation(s)
- Rafael Nagler
- Department of Oral and Maxillofacial Surgery and Laboratory of Oral Biochemistry, Rambam Medical Center and the Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, 31096, Israel.
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