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Vaidya B, Polepalli M, Sharma SS, Singh JN. 2-Aminoethoxydiphenyl borate ameliorates mitochondrial dysfunctions in MPTP/MPP + model of Parkinson's disease. Mitochondrion 2023; 69:95-103. [PMID: 36758857 DOI: 10.1016/j.mito.2023.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/29/2023] [Accepted: 02/04/2023] [Indexed: 02/10/2023]
Abstract
Mitochondrial dysfunction is closely linked with the pathophysiology of several neurodegenerative disorders including Parkinson's disease (PD). Despite several therapeutic advancements related to symptomatic modification of PD pathology, strategies targeting mitochondrial dysfunctions remain largely elusive. Recently, transient receptor potential (TRP) channels have been shown to play a pivotal role in the control of mitochondrial and neuronal functioning in PD. In this study, the effect of 2-aminoethoxydiphenyl borate (2-APB), TRP channel blocker was investigated in the context of mitochondrial dysfunctions in 1-methyl-4-phenylpyridinium (MPP+)-treated SH-SY5Y cells and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-administered Sprague Dawley rats. MPP+-treated SH-SY5Y cells exhibited reductions in cell viability, generation of reactive oxygen species (ROS) and loss of mitochondrial membrane potential. Co-treatment with 2-APB led to an increase in cell viability, reduction in intracellular and mitochondrial ROS and improvement in mitochondrial membrane potential compared to MPP+-treated SH-SY5Y cells. In addition, intranigral administration of MPTP led to a significant reduction in motor function in the rats. Fourteen days of 2-APB (3 and 10 mg/kg, i.p.) treatment improved behavioural parameters. MPTP-induced decrease in complex I activity and mitochondrial potential were also blocked by 2-APB in the mitochondria isolated from the brain regions i.e. midbrain and striatum. MPTP-induced decrease in tyrosine hydroxylase levels were also restored by 2-APB. Moreover, MPTP-induced reduction in proteins involved in mitochondrial biogenesis, viz. peroxisome proliferator-activated-receptor-gamma coactivator and mitochondrial transcription factor-A were increased after 2-APB treatment in vivo. In summary, 2-APB has a promising neuroprotective role in the MPP+/MPTP models of PD via targeting mitochondrial dysfunctions and biogenesis.
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Affiliation(s)
- Bhupesh Vaidya
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), S.A.S. Nagar (Mohali), 160062 Punjab, India
| | - Mahesh Polepalli
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), S.A.S. Nagar (Mohali), 160062 Punjab, India
| | - Shyam Sunder Sharma
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), S.A.S. Nagar (Mohali), 160062 Punjab, India.
| | - Jitendra Narain Singh
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), S.A.S. Nagar (Mohali), 160062 Punjab, India.
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2
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Alfaro IE, Albornoz A, Molina A, Moreno J, Cordero K, Criollo A, Budini M. Chaperone Mediated Autophagy in the Crosstalk of Neurodegenerative Diseases and Metabolic Disorders. Front Endocrinol (Lausanne) 2018; 9:778. [PMID: 30766511 PMCID: PMC6365421 DOI: 10.3389/fendo.2018.00778] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/11/2018] [Indexed: 12/12/2022] Open
Abstract
Chaperone Mediated Autophagy (CMA) is a lysosomal-dependent protein degradation pathway. At least 30% of cytosolic proteins can be degraded by this process. The two major protein players of CMA are LAMP-2A and HSC70. While LAMP-2A works as a receptor for protein substrates at the lysosomal membrane, HSC70 specifically binds protein targets and takes them for CMA degradation. Because of the broad spectrum of proteins able to be degraded by CMA, this pathway has been involved in physiological and pathological processes such as lipid and carbohydrate metabolism, and neurodegenerative diseases, respectively. Both, CMA, and the mentioned processes, are affected by aging and by inadequate nutritional habits such as a high fat diet or a high carbohydrate diet. Little is known regarding about CMA, which is considered a common regulation factor that links metabolism with neurodegenerative disorders. This review summarizes what is known about CMA, focusing on its molecular mechanism, its role in protein, lipid and carbohydrate metabolism. In addition, the review will discuss how CMA could be linked to protein, lipids and carbohydrate metabolism within neurodegenerative diseases. Furthermore, it will be discussed how aging and inadequate nutritional habits can have an impact on both CMA activity and neurodegenerative disorders.
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Affiliation(s)
- Iván E. Alfaro
- Fundación Ciencia & Vida, Santiago, Chile
- *Correspondence: Iván E. Alfaro
| | | | - Alfredo Molina
- Dentistry Faculty, Institute in Dentistry Sciences, University of Chile, Santiago, Chile
| | - José Moreno
- Dentistry Faculty, Institute in Dentistry Sciences, University of Chile, Santiago, Chile
| | - Karina Cordero
- Dentistry Faculty, Institute in Dentistry Sciences, University of Chile, Santiago, Chile
| | - Alfredo Criollo
- Dentistry Faculty, Institute in Dentistry Sciences, University of Chile, Santiago, Chile
- Autophagy Research Center (ARC), Santiago, Chile
- Advanced Center for Chronic Diseases (ACCDiS), University of Chile, Santiago, Chile
| | - Mauricio Budini
- Dentistry Faculty, Institute in Dentistry Sciences, University of Chile, Santiago, Chile
- Autophagy Research Center (ARC), Santiago, Chile
- Mauricio Budini
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3
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Chaperone-mediated autophagy and neurodegeneration: connections, mechanisms, and therapeutic implications. Neurosci Bull 2015. [PMID: 26206600 DOI: 10.1007/s12264-015-1542-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Lysosomes degrade dysfunctional intracellular components via three pathways: macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA). Unlike the other two, CMA degrades cytosolic proteins with a recognized KFERQ-like motif in lysosomes and is important for cellular homeostasis. CMA activity declines with age and is altered in neurodegenerative diseases. Its impairment leads to the accumulation of aggregated proteins, some of which may be directly tied to the pathogenic processes of neurodegenerative diseases. Its induction may accelerate the clearance of pathogenic proteins and promote cell survival, representing a potential therapeutic approach for the treatment of neurodegenerative diseases. In this review, we summarize the current findings on how CMA is involved in neurodegenerative diseases, especially in Parkinson's disease.
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Akin D, Wang SK, Habibzadegah-Tari P, Law B, Ostrov D, Li M, Yin XM, Kim JS, Horenstein N, Dunn WA. A novel ATG4B antagonist inhibits autophagy and has a negative impact on osteosarcoma tumors. Autophagy 2014; 10:2021-35. [PMID: 25483883 PMCID: PMC4502682 DOI: 10.4161/auto.32229] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Autophagy has been implicated in the progression and chemoresistance of various cancers. In this study, we have shown that osteosarcoma Saos-2 cells lacking ATG4B, a cysteine proteinase that activates LC3B, are defective in autophagy and fail to form tumors in mouse models. By combining in silico docking with in vitro and cell-based assays, we identified small compounds that suppressed starvation-induced protein degradation, LC3B lipidation, and formation of autophagic vacuoles. NSC185058 effectively inhibited ATG4B activity in vitro and in cells while having no effect on MTOR and PtdIns3K activities. In addition, this ATG4B antagonist had a negative impact on the development of Saos-2 osteosarcoma tumors in vivo. We concluded that tumor suppression was due to a reduction in ATG4B activity, since we found autophagy suppressed within treated tumors and the compound had no effects on oncogenic protein kinases. Our findings demonstrate that ATG4B is a suitable anti-autophagy target and a promising therapeutic target to treat osteosarcoma.
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Key Words
- 3MA, 3-methyladenine
- ACTB, actin, beta
- ATG, autophagy-related
- ATG4B
- ATG4B, autophagy-related 4B, cysteine protease
- AV, autophagic vacuole
- BECN1, beclin 1, autophagy related
- CMPase, cytidine monophosphatase
- DMEM, Dulbecco's modified Eagle medium
- ECL, enhanced chemiluminescence
- FYVE, zinc-finger domain named after 4 cysteine-rich proteins: FAB1, YOTB, VAC1, and EEA1
- GABARAPL2, GABA(A) receptor-associated protein-like 2
- GFP, green fluorescent protein
- GST, glutathione S-transferase
- HRP, horseradish peroxidase
- IC50, half maximal inhibitory concentration
- IP, intraperitoneal
- LC3B
- MAP1LC3B/LC3B, microtubule-associated protein 1 light chain 3beta
- MP, melting point
- MTOR, mechanistic target of rapamycin
- NCI, National Cancer Institute
- NMR, nuclear magnetic resonance
- PLA2, phospholipase A2
- PVDF, polyvinylidene difluoride
- PtdIns3K, phosphatidylinositol 3-kinase class III
- PtdIns3P, phosphatidylinositol 3-phosphate
- RFP, red fluorescent protein
- RLU, relative luciferase units
- RPS6, ribosomal protein S6
- RPS6KB1, ribosomal protein S6 kinase, 70kDa, polypeptide 1
- SEM, standard error of the mean
- ULK1/2, unc-51-like autophagy activating kinase 1/2
- and xenografts
- antiautophagy compounds
- dNGLUC, Gaussia luciferase
- in silico docking
- osteosarcoma
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Affiliation(s)
- Debra Akin
- a Department of Anatomy and Cell Biology ; University of Florida ; Gainesville , FL USA
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5
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Yamashima T. Reconsider Alzheimer's disease by the 'calpain-cathepsin hypothesis'--a perspective review. Prog Neurobiol 2013; 105:1-23. [PMID: 23499711 DOI: 10.1016/j.pneurobio.2013.02.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 02/08/2013] [Accepted: 02/28/2013] [Indexed: 01/24/2023]
Abstract
Alzheimer's disease (AD) is characterized by slowly progressive neuronal death, but its molecular cascade remains elusive for over 100 years. Since accumulation of autophagic vacuoles (also called granulo-vacuolar degenerations) represents one of the pathologic hallmarks of degenerating neurons in AD, a causative connection between autophagy failure and neuronal death should be present. The aim of this perspective review is at considering such underlying mechanism of AD that age-dependent oxidative stresses may affect the autophagic-lysosomal system via carbonylation and cleavage of heat-shock protein 70.1 (Hsp70.1). AD brains exhibit gradual but continual ischemic insults that cause perturbed Ca(2+) homeostasis, calpain activation, amyloid β deposition, and oxidative stresses. Membrane lipids such as linoleic and arachidonic acids are vulnerable to the cumulative oxidative stresses, generating a toxic peroxidation product 'hydroxynonenal' that can carbonylate Hsp70.1. Recent data advocate for dual roles of Hsp70.1 as a molecular chaperone for damaged proteins and a guardian of lysosomal integrity. Accordingly, impairments of lysosomal autophagy and stabilization may be driven by the calpain-mediated cleavage of carbonylated Hsp70.1, and this causes lysosomal permeabilization and/or rupture with the resultant release of the cell degradation enzyme, cathepsins (calpain-cathepsin hypothesis). Here, the author discusses three topics; (1) how age-related decrease in lysosomal and autophagic activities has a causal connection to programmed neuronal necrosis in sporadic AD, (2) how genetic factors such as apolipoprotein E and presenilin 1 can facilitate lysosomal destabilization in the sequential molecular events, and (3) whether a single cascade can simultaneously account for implications of all players previously reported. In conclusion, Alzheimer neuronal death conceivably occurs by the similar 'calpain-hydroxynonenal-Hsp70.1-cathepsin cascade' with ischemic neuronal death. Blockade of calpain and/or extra-lysosomal cathepsins as well as scavenging of hydroxynonenal would become effective AD therapeutic approaches.
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Affiliation(s)
- Tetsumori Yamashima
- Department of Restorative Neurosurgery, Kanazawa University Graduate School of Medical Science, Takara-machi 13-1, Kanazawa 920-8641, Japan.
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Nijholt DAT, Nölle A, van Haastert ES, Edelijn H, Toonen RF, Hoozemans JJM, Scheper W. Unfolded protein response activates glycogen synthase kinase-3 via selective lysosomal degradation. Neurobiol Aging 2013; 34:1759-71. [PMID: 23415837 DOI: 10.1016/j.neurobiolaging.2013.01.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 12/20/2012] [Accepted: 01/12/2013] [Indexed: 01/01/2023]
Abstract
The unfolded protein response (UPR) is a stress response that is activated upon disturbed homeostasis in the endoplasmic reticulum. In Alzheimer's disease, as well as in other tauopathies, the UPR is activated in neurons that contain early tau pathology. A recent genome-wide association study identified genetic variation in a UPR transducer as a risk factor for tauopathy, supporting a functional connection between UPR activation and tau pathology. Here we show that UPR activation increases the activity of the major tau kinase glycogen synthase kinase (GSK)-3 in vitro via a selective removal of inactive GSK-3 phosphorylated at Ser(21/9). We demonstrate that this is mediated by the autophagy/lysosomal pathway. In brain tissue from patients with different tauopathies, lysosomal accumulations of pSer(21/9) GSK-3 are found in neurons with markers for UPR activation. Our data indicate that UPR activation increases the activity of GSK-3 by a novel mechanism, the lysosomal degradation of the inactive pSer(21/9) GSK-3. This may provide a functional explanation for the close association between UPR activation and early tau pathology in neurodegenerative diseases.
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Affiliation(s)
- Diana A T Nijholt
- Department of Genome Analysis, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
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7
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Demachi-Okamura A, Torikai H, Akatsuka Y, Miyoshi H, Yoshimori T, Kuzushima K. Autophagy creates a CTL epitope that mimics tumor-associated antigens. PLoS One 2012; 7:e47126. [PMID: 23071732 PMCID: PMC3469533 DOI: 10.1371/journal.pone.0047126] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Accepted: 09/10/2012] [Indexed: 12/25/2022] Open
Abstract
The detailed mechanisms responsible for processing tumor-associated antigens and presenting them to CTLs remain to be fully elucidated. In this study, we demonstrate a unique CTL epitope generated from the ubiquitous protein puromycin-sensitive aminopeptidase, which is presented via HLA-A24 on leukemic and pancreatic cancer cells but not on normal fibroblasts or EBV-transformed B lymphoblastoid cells. The generation of this epitope requires proteasomal digestion and transportation from the endoplasmic reticulum to the Golgi apparatus and is sensitive to chloroquine-induced inhibition of acidification inside the endosome/lysosome. Epitope liberation depends on constitutively active autophagy, as confirmed with immunocytochemistry for the autophagosome marker LC3 as well as RNA interference targeting two different autophagy-related genes. Therefore, ubiquitously expressed proteins may be sources of specific tumor-associated antigens when processed through a unique mechanism involving autophagy.
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Affiliation(s)
- Ayako Demachi-Okamura
- Division of Immunology, Aichi Cancer Center Research Institute, Nagoya, Japan
- * E-mail: (ADO); (KK)
| | - Hiroki Torikai
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Yoshiki Akatsuka
- Division of Immunology, Aichi Cancer Center Research Institute, Nagoya, Japan
- Department of Hematology and Oncology, Fujita Health University, Toyoake, Japan
| | - Hiroyuki Miyoshi
- Subteam for Manipulation of Cell Fate, RIKEN BioResource Center, Tsukuba, Japan
| | - Tamotsu Yoshimori
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Kiyotaka Kuzushima
- Division of Immunology, Aichi Cancer Center Research Institute, Nagoya, Japan
- Department of Cellular Oncology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- * E-mail: (ADO); (KK)
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8
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Liang X, De Vera ME, Buchser WJ, Romo de Vivar Chavez A, Loughran P, Stolz DB, Basse P, Wang T, Van Houten B, Zeh HJ, Lotze MT. Inhibiting systemic autophagy during interleukin 2 immunotherapy promotes long-term tumor regression. Cancer Res 2012; 72:2791-801. [PMID: 22472122 PMCID: PMC3417121 DOI: 10.1158/0008-5472.can-12-0320] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Administration of high-dose interleukin-2 (HDIL-2) has durable antitumor effects in 5% to 10% of patients with melanoma and renal cell carcinoma. However, treatment is often limited by side effects, including reversible, multiorgan dysfunction characterized by a cytokine-induced systemic autophagic syndrome. Here, we hypothesized that the autophagy inhibitor chloroquine would enhance IL-2 immunotherapeutic efficacy and limit toxicity. In an advanced murine metastatic liver tumor model, IL-2 inhibited tumor growth in a dose-dependent fashion. These antitumor effects were significantly enhanced upon addition of chloroquine. The combination of IL-2 with chloroquine increased long-term survival, decreased toxicity associated with vascular leakage, and enhanced immune cell proliferation and infiltration in the liver and spleen. HDIL-2 alone increased serum levels of HMGB1, IFN-γ, IL-6, and IL-18 and also induced autophagy within the liver and translocation of HMGB1 from the nucleus to the cytosol in hepatocytes, effects that were inhibited by combined administration with chloroquine. In tumor cells, chloroquine increased autophagic vacuoles and LC3-II levels inhibited oxidative phosphorylation and ATP production and promoted apoptosis, which was associated with increased Annexin-V(+)/propidium iodide (PI)(-) cells, cleaved PARP, cleaved caspase-3, and cytochrome c release from mitochondria. Taken together, our findings provide a novel clinical strategy to enhance the efficacy of HDIL-2 immunotherapy for patients with cancer.
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Affiliation(s)
- Xiaoyan Liang
- Department of Surgery, University of Pittsburgh Cancer Institute, 5117 Centre Avenue, Pittsburgh PA, 15213
| | - Michael E. De Vera
- Department of Surgery, University of Pittsburgh Cancer Institute, 5117 Centre Avenue, Pittsburgh PA, 15213
| | - William J. Buchser
- Department of Surgery, University of Pittsburgh Cancer Institute, 5117 Centre Avenue, Pittsburgh PA, 15213
| | | | - Patricia Loughran
- Department of Surgery, University of Pittsburgh Cancer Institute, 5117 Centre Avenue, Pittsburgh PA, 15213
- Center for Biologic Imaging, University of Pittsburgh
| | | | - Per Basse
- Department of Immunology, University of Pittsburgh
| | - Tao Wang
- UPCI Molecular and Cellular Biology Program. University of Pittsburgh
| | | | - Herbert J. Zeh
- Department of Surgery, University of Pittsburgh Cancer Institute, 5117 Centre Avenue, Pittsburgh PA, 15213
| | - Michael T. Lotze
- Department of Surgery, University of Pittsburgh Cancer Institute, 5117 Centre Avenue, Pittsburgh PA, 15213
- Department of Immunology, University of Pittsburgh
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9
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Ranjbar A, Ghahremani MH, Sharifzadeh M, Golestani A, Ghazi-Khansari M, Baeeri M, Abdollahi M. Protection by pentoxifylline of malathion-induced toxic stress and mitochondrial damage in rat brain. Hum Exp Toxicol 2010; 29:851-64. [PMID: 20194575 DOI: 10.1177/0960327110363836] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE The objective of this study was to investigate the possible protective effects of pentoxifylline as a phosphodiesterase-5 inhibitor on malathion-induced oxidative damage to rat brain mitochondria. METHODS Rats received malathion (200 mg/kg/day) and pentoxifylline (PTX, 50 mg/kg/day) in combination or alone. Alpha-tocopherol (AT, 15 mg/kg/day) was used as a positive standard. After 1 week of treatment, blood, whole brain tissue, and brain mitochondria were isolated. The activity of enzymatic scavengers such as glutathione peroxidase (GPx), catalase (CAT), copper-zinc superoxide dismutase (Cu/ZnSOD), and manganese superoxide dismutase (MnSOD) were measured. The extents of cellular lipid peroxidation (LPO), nitrotyrosine (NOx), and the ratio of reduced versus oxidized glutathione (GSH/GSSG) were determined. The protein expression of MnSOD was determined in brain mitochondria. RESULTS Malathion stimulated activities of CAT, Cu/ZnSOD, GPx, and increased LPO and NOx, and decreased GSH/GSSG in whole brain homogenate. The changes in CAT, LPO, GPx, and GSH/GSSG were restored by PTX and AT. In plasma samples, malathion increased CAT, Cu/ZnSOD, and GPx activities, increased LPO, and decreased GSH/GSSG, while PTX and AT attenuated malathion-induced changes in GPx, Cu/ZnSOD, LPO, and GSH/GSSG. In brain mitochondria, malathion enhanced LPO, NOx, CAT, GPx, and MnSOD and decreased GSH/GSSG as compared to controls, whereas PTX and AT restored malathion-induced changes in GSH/GSSG, NOx, GPx, and CAT. Malathion noticeably enhanced expression of MnSOD protein as compared to controls. Malathion decreased viability of mitochondria that was recovered by AT. It is concluded that oxidative damage is at least in part the mechanism of toxicity of malathion in the mitochondria that can be recovered by PTX comparable to AT.
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Affiliation(s)
- Akram Ranjbar
- Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran, Iran
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10
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Liang X, Chavez ARDV, Schapiro NE, Loughran P, Thorne SH, Amoscato AA, Zeh HJ, Beer-Stolz D, Lotze MT, de Vera ME. Ethyl pyruvate administration inhibits hepatic tumor growth. J Leukoc Biol 2009; 86:599-607. [PMID: 19584311 DOI: 10.1189/jlb.0908578] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
EP is a potent inhibitor of HMGB1 release that has significant anti-inflammatory activities and exerts a protective effect in animal models of inflammation. As inflammation is linked to cancer growth, we hypothesized that EP would have anti-tumor activity and explored its effects in a liver tumor model. Mice injected intraportally with MC38 colorectal cancer cells led to the growth of visible hepatic tumors within 2 weeks. Pretreatment with EP 30 min prior to infusion of tumor cells and continuing daily for 9 days inhibited tumor growth significantly in a dose-dependent manner, with 80 mg/kg EP achieving >70% reduction in the number of tumor nodules when compared with untreated animals. Delayed treatment with EP also suppressed tumor growth significantly, although to a lesser extent. Tumors had early, marked leukocytic infiltrates, and EP administration decreased innate (NK cells, monocytes) and adaptive (T and B cell lymphocytic) immune cell infiltrates acutely and significantly in the liver. Serum IL-6 and HMGB1 levels, which were elevated following tumor injection, were decreased significantly in EP-treated animals. Tumors showed an increase in apoptosis in EP treated mice, and tumor cells treated in vitro with EP had marked increases in LC3-II and cleaved PARP, consistent with enhanced autophagic flux and apoptosis. Thus, EP inhibition of tumor growth in the liver was mediated by tumor (induction of apoptosis) and host (decreased inflammation) effects. EP administration may have a therapeutic role in the treatment of cancer in conjunction with other therapeutic agents.
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Affiliation(s)
- Xiaoyan Liang
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
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11
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Finn PF, Dice JF. Proteolytic and lipolytic responses to starvation. Nutrition 2006; 22:830-44. [PMID: 16815497 DOI: 10.1016/j.nut.2006.04.008] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2005] [Revised: 03/30/2006] [Accepted: 04/12/2006] [Indexed: 01/20/2023]
Abstract
Mammals survive starvation by activating proteolysis and lipolysis in many different tissues. These responses are triggered, at least in part, by changing hormonal and neural statuses during starvation. Pathways of proteolysis that are activated during starvation are surprisingly diverse, depending on tissue type and duration of starvation. The ubiquitin-proteasome system is primarily responsible for increased skeletal muscle protein breakdown during starvation. However, in most other tissues, lysosomal pathways of proteolysis are stimulated during fasting. Short-term starvation activates macroautophagy, whereas long-term starvation activates chaperone-mediated autophagy. Lipolysis also increases in response to starvation, and the breakdown of triacylglycerols provides free fatty acids to be used as an energy source by skeletal muscle and other tissues. In addition, glycerol released from triacylglycerols can be converted to glucose by hepatic gluconeogenesis. During long-term starvation, oxidation of free fatty acids by the liver leads to the production of ketone bodies that can be used for energy by skeletal muscle and brain. Tissues that cannot use ketone bodies for energy respond to these small molecules by activating chaperone-mediated autophagy. This is one form of interaction between proteolytic and lipolytic responses to starvation.
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Affiliation(s)
- Patrick F Finn
- Department of Molecular and Cellular Physiology, Tufts University School of Medicine, Boston, Massachusetts, USA
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12
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Kondo Y, Kanzawa T, Sawaya R, Kondo S. The role of autophagy in cancer development and response to therapy. Nat Rev Cancer 2005; 5:726-34. [PMID: 16148885 DOI: 10.1038/nrc1692] [Citation(s) in RCA: 1319] [Impact Index Per Article: 69.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Autophagy is a process in which subcellular membranes undergo dynamic morphological changes that lead to the degradation of cellular proteins and cytoplasmic organelles. This process is an important cellular response to stress or starvation. Many studies have shed light on the importance of autophagy in cancer, but it is still unclear whether autophagy suppresses tumorigenesis or provides cancer cells with a rescue mechanism under unfavourable conditions. What is the present state of our knowledge about the role of autophagy in cancer development, and in response to therapy? And how can the autophagic process be manipulated to improve anticancer therapeutics?
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Affiliation(s)
- Yasuko Kondo
- Department of Neurosurgery, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030, USA
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13
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Lajoie P, Guay G, Dennis JW, Nabi IR. The lipid composition of autophagic vacuoles regulates expression of multilamellar bodies. J Cell Sci 2005; 118:1991-2003. [PMID: 15840653 DOI: 10.1242/jcs.02324] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multilamellar bodies (MLBs) are responsible for surfactant secretion in type II alveolar cells but also accumulate in other cell types under pathological conditions, including cancer and lysosomal storage diseases such as Niemann-Pick C (NPC), a congenital disease where defective cholesterol transport leads to its accumulation in lysosomes. Mv1Lu type II alveolar cells transfected with Golgi β1,6 N-acetylglucosaminyltransferase V (Mgat5), enhancing the polylactosamine content of complex-type N-glycans, exhibit stable expression of MLBs whose formation requires lysosomal proteolysis within dense autophagic vacuoles. MLBs of Mgat5-transfected Mv1Lu cells are rich in phospholipids and have low levels of cholesterol. In Mv1Lu cells treated with the NPC-mimicking drug U18666A, cholesterol-rich MLBs accumulate independently of both Mgat5 expression and lysosomal proteolysis. Inhibition of autophagy by blocking the PI 3-kinase pathway with 3-methyladenine prevents MLB formation and results in the accumulation of non-lamellar, acidic lysosomal vacuoles. Treatment with 3-methyladenine inhibited the accumulation of monodansylcadaverine, a phospholipid-specific marker for autophagic vacuoles, but did not block endocytic access to the lysosomal vacuoles. Induction of autophagy via serum starvation resulted in an increased size of cholesterol-rich MLBs. Although expression of MLBs in the Mv1Lu cell line can be induced by modulating lysosomal cholesterol or protein glycosylation, an autophagic contribution of phospholipids is critical for the formation of concentric membrane lamellae within late lysosomal organelles.
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Affiliation(s)
- Patrick Lajoie
- Department of Cellular and Physiological Sciences, University of British Columbia, 2177 Wesbrook Mall, Vancouver V6T 1Z3, British Columbia, Canada
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14
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Abstract
Chaperone-mediated autophagy is one of several lysosomal pathways of proteolysis. This pathway is activated by physiological stresses such as prolonged starvation. Cytosolic proteins with particular peptide sequence motifs are recognized by a complex of molecular chaperones and delivered to lysosomes. No vesicular traffic is required for this protein degradation pathway, so it differs from microautophagy and macroautophagy. Protein substrates bind to a receptor in the lysosomal membrane, the lysosome-associated membrane protein (lamp) type 2a. Levels of lamp2a in the lysosomal membrane are controlled by alterations in the lamp2a half-life as well as by the dynamic distribution of the protein between the lysosomal membrane and the lumen. Substrate proteins are unfolded before transport into the lysosome lumen, and the transport of substrate proteins requires a molecular chaperone within the lysosomal lumen. The exact roles of this lysosomal chaperone remain to be defined. The mechanisms of chaperone-mediated autophagy are similar to mechanisms of protein import into mitochondria, chloroplasts, and the endoplasmic reticulum.
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Affiliation(s)
- Amy E Majeski
- Department of Physiology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA.
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15
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Abstract
The degradation of intracellular components in lysosomes (autophagy) has recaptured the attention of cell biologists in recent years. The main reason for this renewed interest is the dissection of the molecular machinery that participates in this process, because the identification of new intracellular elements involved in autophagy has provided new tools to trace, quantify and manipulate autophagy in a growing number of organisms. As a result, a better understanding of the physiological roles of autophagy, the consequences of its malfunctioning and its participation in different pathological processes has emerged. This article reviews our current knowledge of the role of autophagy in disease and the efforts to reconcile its proposed dual function as both a cell protector and a cell killer.
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Affiliation(s)
- Ana Maria Cuervo
- Department of Anatomy and Structural Biology, Marion Bessin Liver Research Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Ullmann B. 614, Bronx, NY 10461, USA.
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16
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Drew B, Leeuwenburgh C. Method for measuring ATP production in isolated mitochondria: ATP production in brain and liver mitochondria of Fischer-344 rats with age and caloric restriction. Am J Physiol Regul Integr Comp Physiol 2003; 285:R1259-67. [PMID: 12855419 DOI: 10.1152/ajpregu.00264.2003] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The production of ATP is vital for muscle contraction, chemiosmotic homeostasis, and normal cellular function. Many studies have measured ATP content or qualitative changes in ATP production, but few have quantified ATP production in vivo in isolated mitochondria. Because of the importance of understanding the energy capacity of mitochondria in biology, physiology, cellular dysfunction, and ultimately, disease pathologies and normal aging, we modified a commercially available bioluminescent ATP determination assay for quantitatively measuring ATP content and rate of ATP production in isolated mitochondria. The bioluminescence assay is based on the reaction of ATP with recombinant firefly luciferase and its substrate luciferin. The stabilities of the reaction mixture as well as relevant ATP standards were quantified. The luminescent signals of the reaction mixture and a 0.5 microM ATP standard decreased linearly at rates of 2.16 and 1.39% decay/min, respectively. For a 25 microM ATP standard, the luminescent signal underwent a logarithmic decay, due to intrinsic deviations from the Beer-Lambert law. Moreover, to test the functionality of isolated mitochondria, they were incubated with 1 and 5 mM oligomycin, an inhibitor of oxidative phosphorylation. The rate of ATP production in the mitochondria declined by 34 and 83%, respectively. Due to the sensitivity and stability of the assay and methodology, we were able to quantitatively measure in vivo the effects of age and caloric restriction on the ATP content and production in isolated mitochondria from the brain and liver of young and old Fischer-344 rats. In both tissues, neither age nor caloric restriction had any significant effect on the ATP content or the rate of ATP production. This study introduces a highly sensitive, reproducible, and quick methodology for measuring ATP in isolated mitochondria.
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Affiliation(s)
- Barry Drew
- Univ. of Florida, Biochemistry of Aging Laboratory, P.O. Box 118206, Gainesville, FL 32611, USA
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