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Montecillo-Aguado M, Tirado-Rodriguez B, Huerta-Yepez S. The Involvement of Polyunsaturated Fatty Acids in Apoptosis Mechanisms and Their Implications in Cancer. Int J Mol Sci 2023; 24:11691. [PMID: 37511450 PMCID: PMC10380946 DOI: 10.3390/ijms241411691] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/12/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023] Open
Abstract
Cancer is a significant global public health issue and, despite advancements in detection and treatment, the prognosis remains poor. Cancer is a complex disease characterized by various hallmarks, including dysregulation in apoptotic cell death pathways. Apoptosis is a programmed cell death process that efficiently eliminates damaged cells. Several studies have indicated the involvement of polyunsaturated fatty acids (PUFAs) in apoptosis, including omega-3 PUFAs such as alpha-linolenic acid, docosahexaenoic acid, and eicosapentaenoic acid. However, the role of omega-6 PUFAs, such as linoleic acid, gamma-linolenic acid, and arachidonic acid, in apoptosis is controversial, with some studies supporting their activation of apoptosis and others suggesting inhibition. These PUFAs are essential fatty acids, and Western populations today have a high consumption rate of omega-6 to omega-3 PUFAs. This review focuses on presenting the diverse molecular mechanisms evidence in both in vitro and in vivo models, to help clarify the controversial involvement of omega-3 and omega-6 PUFAs in apoptosis mechanisms in cancer.
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Affiliation(s)
- Mayra Montecillo-Aguado
- Unidad de Investigacion en Enfermedades Oncologicas, Hospital Infantil de Mexico, Federico Gomez, Mexico City 06720, Mexico
- Programa de Doctorado en Ciencias Biomédicas, Facultad de Medicina, Universidad Nacional Autónoma de Mexico (UNAM), Mexico City 04510, Mexico
| | - Belen Tirado-Rodriguez
- Unidad de Investigacion en Enfermedades Oncologicas, Hospital Infantil de Mexico, Federico Gomez, Mexico City 06720, Mexico
| | - Sara Huerta-Yepez
- Unidad de Investigacion en Enfermedades Oncologicas, Hospital Infantil de Mexico, Federico Gomez, Mexico City 06720, Mexico
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William S, Duncan T, Redmond TM. Pretreatment of human retinal pigment epithelial cells with sterculic acid forestalls fenretinide-induced apoptosis. Sci Rep 2022; 12:22442. [PMID: 36575190 PMCID: PMC9794835 DOI: 10.1038/s41598-022-26383-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 12/14/2022] [Indexed: 12/28/2022] Open
Abstract
The ratio of saturated to monounsaturated fatty acids, thought to play a critical role in many cellular functions, is regulated by stearoyl-CoA desaturase (SCD), a rate-limiting enzyme in the biosynthesis of monounsaturated fatty acids. Previously, we observed a decrease in both SCD protein and enzymatic activity in apoptosis induced by fenretinide, a synthetic analog of retinoic acid, in the human retinal pigment epithelial (RPE) cell line ARPE-19. Here, we investigated the effect of pretreating ARPE-19 with sterculic acid, a cyclopropenoic fatty acid inhibitor of SCD, on preventing fenretinide-induced apoptosis, given the role of SCD in cell proliferation and apoptosis. We show that sterculic acid pretreatment prevents the effects of fenretinide-induced apoptosis shown by changes in cell morphology, viability, and caspase-3 activation. Analysis of endoplasmic reticulum (ER)-associated proteins shows that sterculic acid pretreatment reduced the fenretinide-induced upregulation of heme oxygenase-1, ATF3 and GADD153 expression that are in response to reactive oxygen species (ROS) generation. Sterculic acid is as effective as allopurinol in inhibition of xanthine oxidase (XDH), and this may play a role in reducing the potential role of XDH in fenretinide-induced ROS generation. Sterculic acid pretreatment also results in a reduction in SOD2 mRNA expression. Dihydroceramide accumulation, compared to ceramide, and ROS generation indicate that a ceramide-independent pathway mediates fenretinide-induced apoptosis, and ROS mediation is borne out by activation of the NF-κBp50 and NF-κBp65 downstream signaling cascade. Its prevention by sterculic acid pretreatment further indicates the latter's antioxidant/anti-inflammatory effect. Taken together, our results suggest that sterculic acid pretreatment can mitigate ROS-mediated fenretinide-induced apoptosis. Thus, sterculic acid may serve as a potential antioxidant and therapeutic agent. These effects may be independent of its effects on SCD activity.
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Affiliation(s)
- Samuel William
- grid.280030.90000 0001 2150 6316Laboratory of Retinal Cell and Molecular Biology, Bldg. 6/Room 112A, National Eye Institute, National Institutes of Health, 6 Center Drive, Bethesda, MD 20892-0608 USA
| | - Todd Duncan
- grid.280030.90000 0001 2150 6316Laboratory of Retinal Cell and Molecular Biology, Bldg. 6/Room 112A, National Eye Institute, National Institutes of Health, 6 Center Drive, Bethesda, MD 20892-0608 USA
| | - T. Michael Redmond
- grid.280030.90000 0001 2150 6316Laboratory of Retinal Cell and Molecular Biology, Bldg. 6/Room 112A, National Eye Institute, National Institutes of Health, 6 Center Drive, Bethesda, MD 20892-0608 USA
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3
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Montecillo-Aguado M, Tirado-Rodriguez B, Antonio-Andres G, Morales-Martinez M, Tong Z, Yang J, Hammock BD, Hernandez-Pando R, Huerta-Yepez S. Omega-6 Polyunsaturated Fatty Acids Enhance Tumor Aggressiveness in Experimental Lung Cancer Model: Important Role of Oxylipins. Int J Mol Sci 2022; 23:6179. [PMID: 35682855 PMCID: PMC9181584 DOI: 10.3390/ijms23116179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 01/27/2023] Open
Abstract
Lung cancer is currently the leading cause of cancer death worldwide; it is often diagnosed at an advanced stage and bears poor prognosis. It has been shown that diet is an important environmental factor that contributes to the risk and mortality of several types of cancers. Intake of ω-3 and ω-6 PUFAs plays an important role in cancer risk and progression. Current Western populations have high consumption of ω-6 PUFAs with a ratio of ω-6/ω-3 PUFAs at 15:1 to 16.7:1 This high consumption of ω-6 PUFAs is related to increased cancer risk and progression. However, whether a diet rich in ω-6 PUFAs can contribute to tumor aggressiveness has not been well investigated. We used a murine model of pulmonary squamous cell carcinoma to study the aggressiveness of tumors in mice fed with a diet rich in ω-6 PUFAs and its relationship with oxylipins. Our results shown that the mice fed a diet rich in ω-6 showed a marked increase in proliferation, angiogenesis and pro-inflammatory markers and decreased expression of pro-apoptotic proteins in their tumors. Oxylipin profiling revealed an upregulation of various pro-tumoral oxylipins including PGs, HETEs, DiHETrEs and HODEs. These results demonstrate for the first time that high intake of ω-6 PUFAs in the diet enhances the malignancy of tumor cells by histological changes on tumor dedifferentiation and increases cell proliferation, angiogenesis, pro-inflammatory oxylipins and molecular aggressiveness targets such as NF-κB p65, YY1, COX-2 and TGF-β.
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Affiliation(s)
- Mayra Montecillo-Aguado
- Programa de Doctorado en Ciencias Biomédicas, Facultad de Medicina, Universidad Nacional Autonoma de Mexico (UNAM), Mexico City 04510, Mexico;
- Unidad de Investigacion en Enfermedades Oncologicas, Hospital Infantil de Mexico, Federico Gomez, Mexico City 06720, Mexico; (B.T.-R.); (G.A.-A.); (M.M.-M.)
| | - Belen Tirado-Rodriguez
- Unidad de Investigacion en Enfermedades Oncologicas, Hospital Infantil de Mexico, Federico Gomez, Mexico City 06720, Mexico; (B.T.-R.); (G.A.-A.); (M.M.-M.)
| | - Gabriela Antonio-Andres
- Unidad de Investigacion en Enfermedades Oncologicas, Hospital Infantil de Mexico, Federico Gomez, Mexico City 06720, Mexico; (B.T.-R.); (G.A.-A.); (M.M.-M.)
| | - Mario Morales-Martinez
- Unidad de Investigacion en Enfermedades Oncologicas, Hospital Infantil de Mexico, Federico Gomez, Mexico City 06720, Mexico; (B.T.-R.); (G.A.-A.); (M.M.-M.)
| | - Zhen Tong
- Molecular Toxicology Interdepartmental Program and Environmental Health Sciences, University of California, Los Angeles, CA 90095, USA;
- Department of Pathology & Laboratory Medicine, University of California, Los Angeles, CA 90095, USA
| | - Jun Yang
- Comprehensive Cancer Center, Department of Entomology and Nematology, University of California, Davis, CA 95616, USA; (J.Y.); (B.D.H.)
| | - Bruce D. Hammock
- Comprehensive Cancer Center, Department of Entomology and Nematology, University of California, Davis, CA 95616, USA; (J.Y.); (B.D.H.)
| | - Rogelio Hernandez-Pando
- Experimental Pathology Section, Department of Pathology, National Institute of Medical Science and Nutrition, Salvador Zubiran (INCNSZ), Mexico City 14080, Mexico;
| | - Sara Huerta-Yepez
- Unidad de Investigacion en Enfermedades Oncologicas, Hospital Infantil de Mexico, Federico Gomez, Mexico City 06720, Mexico; (B.T.-R.); (G.A.-A.); (M.M.-M.)
- Department of Pathology & Laboratory Medicine, University of California, Los Angeles, CA 90095, USA
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Meulmeester FL, Luo J, Martens LG, Ashrafi N, de Mutsert R, Mook-Kanamori DO, Lamb HJ, Rosendaal FR, Willems van Dijk K, Mills K, van Heemst D, Noordam R. Association of measures of body fat with serum alpha-tocopherol and its metabolites in middle-aged individuals. Nutr Metab Cardiovasc Dis 2021; 31:2407-2415. [PMID: 34158242 DOI: 10.1016/j.numecd.2021.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 05/04/2021] [Accepted: 05/04/2021] [Indexed: 11/15/2022]
Abstract
BACKGROUND AND AIMS The accumulation of fat increases the formation of lipid peroxides, which are partly scavenged by alpha-tocopherol (α-TOH). Here, we aimed to investigate the associations between different measures of (abdominal) fat and levels of urinary α-TOH metabolites in middle-aged individuals. METHODS AND RESULTS In this cross-sectional analysis in the Netherlands Epidemiology of Obesity study (N = 511, 53% women; mean [SD] age of 55 [6.1] years), serum α-TOH and α-TOH metabolites from 24-h urine were measured as alpha-tocopheronolactone hydroquinone (α-TLHQ, oxidized) and alpha-carboxymethyl-hydroxychroman (α-CEHC, enzymatically converted) using liquid-chromatography-tandem mass spectrometry. Body mass index and total body fat were measured, and abdominal subcutaneous and visceral adipose tissue (aSAT and VAT) were assessed using magnetic resonance imaging. Using multivariable-adjusted linear regression analyses, we analysed the associations of BMI, TBF, aSAT and VAT with levels of urinary α-TOH metabolites, adjusted for confounders. We observed no evidence for associations between body fat measures and serum α-TOH. Higher BMI and TBF were associated with lower urinary levels of TLHQ (0.95 [95%CI: 0.90, 1.00] and 0.94 [0.88, 1.01] times per SD, respectively) and with lower TLHQ relative to CEHC (0.93 [0.90, 0.98] and 0.93 [0.87, 0.98] times per SD, respectively). We observed similar associations for VAT (TLHQ: 0.94 [0.89, 0.99] times per SD), but not for aSAT. CONCLUSIONS Opposite to our research hypothesis, higher abdominal adiposity was moderately associated with lower levels of oxidized α-TOH metabolites, which might reflect lower vitamin E antioxidative activity in individuals with higher abdominal fat instead.
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Affiliation(s)
- Fleur L Meulmeester
- Department of Internal Medicine, Section of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, the Netherlands; NIHR Great Ormond Street Biomedical Research Centre, Great Ormond Street Hospital and UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Jiao Luo
- Department of Internal Medicine, Section of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, the Netherlands; Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Leon G Martens
- Department of Internal Medicine, Section of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, the Netherlands
| | - Nadia Ashrafi
- NIHR Great Ormond Street Biomedical Research Centre, Great Ormond Street Hospital and UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Renée de Mutsert
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Dennis O Mook-Kanamori
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands; Department of Public Health and Primary Care, Leiden University Medical Center, Leiden, the Netherlands
| | - Hildo J Lamb
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Frits R Rosendaal
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Ko Willems van Dijk
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands; Department of Internal Medicine, Division of Endocrinology, Leiden University Medical Center, Leiden, the Netherlands; Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Kevin Mills
- NIHR Great Ormond Street Biomedical Research Centre, Great Ormond Street Hospital and UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Diana van Heemst
- Department of Internal Medicine, Section of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, the Netherlands
| | - Raymond Noordam
- Department of Internal Medicine, Section of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, the Netherlands.
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Eid RA, Alkhateeb MA, El-Kott AF, Eleawa SM, Zaki MSA, Alaboodi SA, Salem Al-Shudiefat AAR, Aldera H, Alnamar NM, Alassiri M, Khalil MA. A high-fat diet rich in corn oil induces cardiac fibrosis in rats by activating JAK2/STAT3 and subsequent activation of ANG II/TGF-1β/Smad3 pathway: The role of ROS and IL-6 trans-signaling. J Food Biochem 2019; 43:e12952. [PMID: 31368573 DOI: 10.1111/jfbc.12952] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 05/30/2019] [Accepted: 05/31/2019] [Indexed: 12/20/2022]
Abstract
This study compared the effect of low-fat diet (LFD) and high-fat diet rich in corn oil (HFD-CO) on left ventricular (LV) fibrosis in rats and examined their effect of angiotensin II (ANG II), JAK/STAT, and TGF-1β/smad3 pathways. As compared to LFD which didn't affect any of the measured parameters, HFD-CO-induced type 2 diabetes phenotype and increased LV collagen synthesis. Mechanistically, it increased LV levels of ROS, ANG II, ACE, IL-6, s-IL-6Rα, TGF-β1, Smad-3, and activities of JAK1/2 and STAT1/3. AG490, a JAK2 inhibitor, partially ameliorated these effect while Losartan, an AT1 inhibitor completely abolished collagen synthesis. However, with both treatments, levels of ANG II, IL-6, and s-IL-6Rα, and activity of JAK1/STAT3 remained high, all of which were normalized by co-administration of NAC or IL-6 neutralizing antibody. In conclusion: HFD-CO enhances LV collage synthesis by activation of JAK1/STAT3/ANG II/TGF-1β/smad3 pathway. PRACTICAL APPLICATIONS: We report that chronic consumption of a high-fat diet rich in corn oil (HFD-CO) induces diabetes mellitus phenotype 2 associated with left ventricular (LV) cardiac fibrosis in rats. The findings of this study show that HFD-CO, and through the increasing generation of ROS and IL-6 levels and shedding, could activate LV JAK1/2-STAT1/3 and renin-angiotensin system (RAS) signaling pathways, thus creating a positive feedback between the two which ultimately leads to activation of TGF-1β/Smad3 fibrotic pathway. Herein, we also report a beneficial effect of the antioxidant, NAC, or IL-6 neutralizing antibody in preventing such adverse effects of such HFD-CO. However, this presents a warning message to the current sudden increase in idiopathic cardiac disorders, especially with the big shift in our diets toward n-6 PUFA.
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Affiliation(s)
- Refaat A Eid
- Department of Clinica Pathology and Anatomy, College of Medicine, King Khalid University (KKU), Abha, Kingdom of Saudi Arabia
| | - Mahmoud A Alkhateeb
- Basic Medical Sciences (Physiology Section), College of Medicine, King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), Riyadh, Kingdom of Saudi Arabia
| | - Attalla Farag El-Kott
- Department of Biology, College of Science, King Khalid University (KKU), Abha, Kingdom of Saudi Arabia.,Department of Zoology, Faculty of Science, Damanhour University, Damanhour, Egypt
| | - Samy M Eleawa
- Department of Applied Medical Sciences, College of Health Sciences, PAAET, Safat, Kuwait
| | - Mohamed Samir Ahmed Zaki
- Department of Anatomy, College of Medicine, King Khalid University (KKU), Abha, Kingdom of Saudi Arabia.,Department of Histology, Faculty of Medicine, Zagazig University, Zagazig, Egypt
| | - Sultan Abdullah Alaboodi
- Central laboratories, Huraymala General Hospital, Ministry of Health, Riyadh, Kingdom of Saudi Arabia
| | | | - Hussain Aldera
- Basic Medical Sciences (Physiology Section), College of Medicine, King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), Riyadh, Kingdom of Saudi Arabia.,King Abdullah International Medical Research Center, Riyadh, Kingdom of Saudi Arabia
| | | | - Mohammed Alassiri
- Basic Medical Sciences (Physiology Section), College of Medicine, King Saud bin Abdulaziz University for Health Sciences (KSAU-HS), Riyadh, Kingdom of Saudi Arabia.,King Abdullah International Medical Research Center, Riyadh, Kingdom of Saudi Arabia
| | - Mohammad A Khalil
- Department of Basic Medical Sciences, College of Medicine, King Fahid Medical City (KFMC), Riyadh, Kingdom of Saudi Arabia
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Li J, Li O, Kan M, Zhang M, Shao D, Pan Y, Zheng H, Zhang X, Chen L, Liu S. Berberine induces apoptosis by suppressing the arachidonic acid metabolic pathway in hepatocellular carcinoma. Mol Med Rep 2015; 12:4572-4577. [PMID: 26081696 DOI: 10.3892/mmr.2015.3926] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 05/06/2015] [Indexed: 11/06/2022] Open
Abstract
Berberine (BBR) has been suggested as a potential candidate anticancer agent due to its high anticancer activity and multiple mechanisms. In the present study, the inhibitory effect of BBR on hepatocellular carcinoma (HCC) via the suppression of the arachidonic acid (AA) metabolic pathway was investigated. BBR was demonstrated to reduce the viabilities of H22, HepG2 and Bel‑7404 cells, in a dose‑ and time‑dependent manner, and increase the number of apoptotic cells. BBR induced the translocation of apoptosis‑inducing factor between the mitochondria and the nucleus, and had no effects on the protein expression levels of caspase‑3 or ‑9. In addition, BBR significantly suppressed the protein expression levels of cytosolic phospholipase A2 (cPLA2) and cyclooxygenase (COX)‑2 and elevated the content ratio of AA to prostaglandin E2 (PGE2). Furthermore, BBR reduced the volume and weight of tumors in a H22 transplanted tumor model in mice. The results of the present study demonstrated that elevation in the ratio of AA to PGE2 via suppression of the protein expression of cPLA2 and COX‑2 in the AA metabolic pathway is involved in the inhibitory effect of BBR in HCC.
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Affiliation(s)
- Jing Li
- Department of Pharmacology, Basic Medical School, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Ou Li
- Department of Pharmacology, Basic Medical School, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Mujie Kan
- Department of Pharmacology, Basic Medical School, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Ming Zhang
- Department of Pharmacology, Basic Medical School, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Dan Shao
- Department of Pharmacology, Basic Medical School, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Yue Pan
- Department of Pharmacology, Basic Medical School, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Huilin Zheng
- Department of Pharmacology, Basic Medical School, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Xuewen Zhang
- Department of Hepatobiliary and Pancreatic Surgery, China‑Japan Union Hospital of Jilin University, Chanchun, Jilin 130031, P.R. China
| | - Li Chen
- Department of Pharmacology, Basic Medical School, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Songyan Liu
- Manitoba Institute of Cell Biology and Faculty of Pharmacy, University of Manitoba, Winnipeg, MB R3E 0V9, Canada
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Xia J, Giovannozzi AM, Sadeghi SJ, Gilardi G, Rossi AM. Laser-written nanoporous silicon diffraction gratings for biosensors. APPLIED OPTICS 2013; 52:8802-8808. [PMID: 24513946 DOI: 10.1364/ao.52.008802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 11/20/2013] [Indexed: 06/03/2023]
Abstract
Surface-relief diffraction gratings and planar diffraction gratings directly written on nanoporous silicon layers using 514 nm continuous-wave lasers at very low power (less than 20 mW) were demonstrated. Diffraction-based biosensing application to detect arachidonic acid was experimentally demonstrated at incident light wavelength of 632.8 nm. A comparison in sensing applications was made between the two types of gratings to show the distinct advantage of the planar grating with selective functionalization. Laser-written planar gratings enable directly immobilizing biomolecules in the laser oxidized area of nanoporous silicon, resulting in a new patterned functionalization technique for biosensing applications. The functionalization technique can not only simplify the functionalization procedure in biosensing but also it has potential to increase the sensitivity of sensors by accurately defining grating patterns using the laser direct writing technique.
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The biological activities of protein/oleic acid complexes reside in the fatty acid. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:1125-43. [DOI: 10.1016/j.bbapap.2013.02.041] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 02/18/2013] [Accepted: 02/20/2013] [Indexed: 12/12/2022]
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Nakamura T, Aizawa T, Kariya R, Okada S, Demura M, Kawano K, Makabe K, Kuwajima K. Molecular mechanisms of the cytotoxicity of human α-lactalbumin made lethal to tumor cells (HAMLET) and other protein-oleic acid complexes. J Biol Chem 2013; 288:14408-14416. [PMID: 23580643 DOI: 10.1074/jbc.m112.437889] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Although HAMLET (human α-lactalbumin made lethal to tumor cells), a complex formed by human α-lactalbumin and oleic acid, has a unique apoptotic activity for the selective killing of tumor cells, the molecular mechanisms of expression of the HAMLET activity are not well understood. Therefore, we studied the molecular properties of HAMLET and its goat counterpart, GAMLET (goat α-lactalbumin made lethal to tumor cells), by pulse field gradient NMR and 920-MHz two-dimensional NMR techniques. We also examined the expression of HAMLET-like activities of complexes between oleic acid and other proteins that form a stable molten globule state. We observed that both HAMLET and GAMLET at pH 7.5 were heterogeneous, composed of the native protein, the monomeric molten globule-like state, and the oligomeric species. At pH 2.0 and 50 °C, HAMLET and GAMLET appeared in the monomeric state, and we identified the oleic acid-binding site in the complexes by two-dimensional NMR. Rather surprisingly, the binding site thus identified was markedly different between HAMLET and GAMLET. Furthermore, canine milk lysozyme, apo-myoglobin, and β2-microglobulin all formed the HAMLET-like complex with the anti-tumor activity, when the protein was treated with oleic acid under conditions in which their molten globule states were stable. From these results, we conclude that the protein portion of HAMLET, GAMLET, and the other HAMLET-like protein-oleic acid complexes is not the origin of their cytotoxicity to tumor cells and that the protein portion of these complexes plays a role in the delivery of cytotoxic oleic acid molecules into tumor cells across the cell membrane.
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Affiliation(s)
- Takashi Nakamura
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Tomoyasu Aizawa
- Faculty of Advanced Life Science, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo 060-0810, Japan
| | - Ryusho Kariya
- Division of Hematopoiesis, Center for AIDS Research, Kumamoto University, 2-2-1, Honjo, Chuo-ku, Kumamoto 860-0811, Japan
| | - Seiji Okada
- Division of Hematopoiesis, Center for AIDS Research, Kumamoto University, 2-2-1, Honjo, Chuo-ku, Kumamoto 860-0811, Japan
| | - Makoto Demura
- Faculty of Advanced Life Science, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo 060-0810, Japan
| | - Keiichi Kawano
- Faculty of Advanced Life Science, Hokkaido University, Kita-10 Nishi-8, Kita-ku, Sapporo 060-0810, Japan
| | - Koki Makabe
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan; Department of Functional Molecular Science, School of Physical Sciences, Graduate University for Advanced Studies (Sokendai), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Kunihiro Kuwajima
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan; Department of Functional Molecular Science, School of Physical Sciences, Graduate University for Advanced Studies (Sokendai), 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan.
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10
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Brinkmann CR, Thiel S, Otzen DE. Protein-fatty acid complexes: biochemistry, biophysics and function. FEBS J 2013; 280:1733-49. [DOI: 10.1111/febs.12204] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 11/29/2012] [Accepted: 02/12/2013] [Indexed: 02/01/2023]
Affiliation(s)
| | - Steffen Thiel
- Department of Biomedicine, Faculty of Health Sciences; Aarhus University; Denmark
| | - Daniel E. Otzen
- Interdisciplinary Nanoscience Centre (iNANO), Centre for Insoluble Protein Structures (inSPIN), Department of Molecular Biology and Genetics; Aarhus University; Denmark
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11
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Ho CS J, Rydstrom A, Manimekalai MSS, Svanborg C, Grüber G. Low resolution solution structure of HAMLET and the importance of its alpha-domains in tumoricidal activity. PLoS One 2012; 7:e53051. [PMID: 23300861 PMCID: PMC3531425 DOI: 10.1371/journal.pone.0053051] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 11/26/2012] [Indexed: 11/18/2022] Open
Abstract
HAMLET (Human Alpha-lactalbumin Made LEthal to Tumor cells) is the first member in a new family of protein-lipid complexes with broad tumoricidal activity. Elucidating the molecular structure and the domains crucial for HAMLET formation is fundamental for understanding its tumoricidal function. Here we present the low-resolution solution structure of the complex of oleic acid bound HAMLET, derived from small angle X-ray scattering data. HAMLET shows a two-domain conformation with a large globular domain and an extended part of about 2.22 nm in length and 1.29 nm width. The structure has been superimposed into the related crystallographic structure of human α-lactalbumin, revealing that the major part of α-lactalbumin accommodates well in the shape of HAMLET. However, the C-terminal residues from L105 to L123 of the crystal structure of the human α-lactalbumin do not fit well into the HAMLET structure, resulting in an extended conformation in HAMLET, proposed to be required to form the tumoricidal active HAMLET complex with oleic acid. Consistent with this low resolution structure, we identified biologically active peptide epitopes in the globular as well as the extended domains of HAMLET. Peptides covering the alpha1 and alpha2 domains of the protein triggered rapid ion fluxes in the presence of sodium oleate and were internalized by tumor cells, causing rapid and sustained changes in cell morphology. The alpha peptide-oleate bound forms also triggered tumor cell death with comparable efficiency as HAMLET. In addition, shorter peptides corresponding to those domains are biologically active. These findings provide novel insights into the structural prerequisites for the dramatic effects of HAMLET on tumor cells.
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Affiliation(s)
- James Ho CS
- Department of Microbiology, Immunology and Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Lund, Sweden
| | - Anna Rydstrom
- Department of Microbiology, Immunology and Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Lund, Sweden
| | | | - Catharina Svanborg
- Department of Microbiology, Immunology and Glycobiology (MIG), Institute of Laboratory Medicine, Lund University, Lund, Sweden
- * E-mail: (CS); (GG)
| | - Gerhard Grüber
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
- * E-mail: (CS); (GG)
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12
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Gyamfi D, Everitt HE, Tewfik I, Clemens DL, Patel VB. Hepatic mitochondrial dysfunction induced by fatty acids and ethanol. Free Radic Biol Med 2012; 53:2131-45. [PMID: 23010494 DOI: 10.1016/j.freeradbiomed.2012.09.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 09/14/2012] [Accepted: 09/15/2012] [Indexed: 02/08/2023]
Abstract
Understanding the key aspects of the pathogenesis of alcoholic fatty liver disease particularly alterations to mitochondrial function remains to be resolved. The role of fatty acids in this regard requires further investigation due to their involvement in fatty liver disease and obesity. This study aimed to characterize the early effects of saturated and unsaturated fatty acids alone on liver mitochondrial function and during concomitant ethanol exposure using isolated liver mitochondria and VA-13 cells (Hep G2 cells that efficiently express alcohol dehydrogenase). Liver mitochondria or VA-13 cells were treated with increasing concentrations of palmitic or arachidonic acid (1 to 160 μM) for 24 h with or without 100 mM ethanol. The results showed that in isolated liver mitochondria both palmitic and arachidonic acids significantly reduced state 3 respiration in a concentration-dependent manner (P<0.001), implicating their ionophoric activities. Increased ROS production occurred in a dose-dependent manner especially in the presence of rotenone (complex I inhibitor), which was significantly more prominent in arachidonic acid at 80 μM (+970%, P<0.001) than palmitic acid (+40%, P<0.01). In VA-13 cells, ethanol alone and both fatty acids (40 μM) were able to decrease the mitochondrial membrane potential and cellular ATP levels and increase lipid formation. ROS production was significantly increased with arachidonic acid (+110%, P<0.001) exhibiting a greater effect than palmitic acid (+39%, P<0.05). While in the presence of ethanol, the drop in the mitochondrial membrane potential, cellular ATP levels, and increased lipid formation were further enhanced by both fatty acids, but with greater effect in the case of arachidonic acid, which also correlated with significant cytotoxicity (P<0.001). This study confirms the ability of fatty acids to promote mitochondrial injury in the development of alcoholic fatty liver disease.
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Affiliation(s)
- Daniel Gyamfi
- Department of Biomedical Sciences, School of Life Sciences, University of Westminster, 115 New Cavendish Street, London, W1W 6UW, UK
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13
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P450-based porous silicon biosensor for arachidonic acid detection. Biosens Bioelectron 2011; 28:320-5. [DOI: 10.1016/j.bios.2011.07.046] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 07/17/2011] [Indexed: 12/19/2022]
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14
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Khan AA, Alam M, Tufail S, Mustafa J, Owais M. Synthesis and characterization of novel PUFA esters exhibiting potential anticancer activities: an in vitro study. Eur J Med Chem 2011; 46:4878-86. [PMID: 21868138 DOI: 10.1016/j.ejmech.2011.07.044] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 07/26/2011] [Accepted: 07/26/2011] [Indexed: 10/17/2022]
Abstract
Polyunsaturated fatty acids (PUFAs) have been reported to play a regulatory role in tumour growth progression. In the present study, we have synthesized ester derivatives of two important PUFA viz., linoleic acid (LA) and arachidonic acid (AA) with propofol, a widely used general anaesthetic-sedative agent. The novel propofol ester analogues have been found to inhibit various cancer cell lines in a dose-dependent manner. Moreover, the compounds have been found to induce apoptotic cell death by enhancing the release of cytochrome c and expression of caspase-3. The data of the present study suggest that novel propofol-PUFA esters have strong potential to emerge as effective anticancer agents.
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Affiliation(s)
- Azmat Ali Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India
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15
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Mechanism(s) of Toxic Action of Zn and Selenite: A Study on AS-30D Hepatoma Cells and Isolated Mitochondria. Biochem Res Int 2011; 2011:387297. [PMID: 21860797 PMCID: PMC3154521 DOI: 10.1155/2011/387297] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 06/06/2011] [Indexed: 02/05/2023] Open
Abstract
Mitochondria of AS-30D rat ascites hepatoma cells are found to be the main target for Zn2+ and sodium selenite (Na2SeO3). High [mu]M concentrations of Zn2+ or selenite were strongly cytotoxic, killing the AS-30D cells by both apoptotic and necrotic ways. Both Zn2+ and selenite produced strong changes in intracellular generation of reactive oxygen species (ROS) and the mitochondrial dysfunction via the mitochondrial electron transport chain (mtETC) disturbance, the membrane potential dissipation, and the mitochondrial permeability transition pore opening. The significant distinctions in toxic action of Zn2+ and selenite on AS-30D cells were found. Selenite induced a much higher intracellular ROS level (the early event) compared to Zn2+ but a lower membrane potential loss and a lower decrease of the uncoupled respiration rate of the cells, whereas the mtETC disturbance was the early and critical event in the mechanism of Zn2+ cytotoxicity. Sequences of events manifested in the mitochondrial dysfunction produced by the metal/metalloid under test are compared with those obtained earlier for Cd2+, Hg2+, and Cu2+ on the same model system.
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16
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Serini S, Piccioni E, Merendino N, Calviello G. Dietary polyunsaturated fatty acids as inducers of apoptosis: implications for cancer. Apoptosis 2009; 14:135-52. [DOI: 10.1007/s10495-008-0298-2] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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17
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Belyaeva EA, Dymkowska D, Wieckowski MR, Wojtczak L. Mitochondria as an important target in heavy metal toxicity in rat hepatoma AS-30D cells. Toxicol Appl Pharmacol 2008; 231:34-42. [PMID: 18501399 DOI: 10.1016/j.taap.2008.03.017] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 02/12/2008] [Accepted: 03/22/2008] [Indexed: 02/05/2023]
Abstract
The mechanisms of toxic effects of divalent cations of three heavy metals Hg, Cd and Cu in rat ascites hepatoma AS-30D cells cultivated in vitro were compared. It was found that the toxicity of these ions, applied in the micromolar range (10-500 microM), decreased from Hg(2+) (most toxic) to Cu(2+) (least toxic). Hg(2+) and Cd(2+) produced a high percentage of cell death by both necrosis and apoptosis, whereas Cu(2+) at concentrations up to 500 microM was weakly effective. Hg(2+) at concentration of 10 microM appeared slightly uncoupling (i.e., stimulated resting state respiration and decreased the mitochondrial transmembrane potential), whereas it exerted a strong inhibitory effect on the respiratory chain and rapid dissipation of the membrane potential at higher concentrations. Cu(2+) had inhibitory effect on cell respiration only at 500 microM concentration and after incubation of 48 h but produced a significant uncoupling effect at lower concentrations. Cu(2+) induced an early and sharp increase of intracellular production of reactive oxygen species (ROS). The action of Hg(2+) and Cd(2+) on ROS generation was biphasic. They stimulated ROS generation within the cells at low concentrations and at short incubation times but decreased ROS generation at higher concentrations and at longer incubation. It is concluded that mitochondria are an important target for toxic effects of Hg(2+), Cd(2+) and Cu(2+) in AS-30D rat hepatoma cells.
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Affiliation(s)
- Elena A Belyaeva
- Laboratory of Comparative Biochemistry of Inorganic Ions, Sechenov Institute of Evolutionary Physiology and Biochemistry, Thorez pr. 44, 194223, St. Petersburg, Russia.
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18
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Schönfeld P, Wojtczak L. Fatty acids as modulators of the cellular production of reactive oxygen species. Free Radic Biol Med 2008; 45:231-41. [PMID: 18482593 DOI: 10.1016/j.freeradbiomed.2008.04.029] [Citation(s) in RCA: 308] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 04/16/2008] [Accepted: 04/22/2008] [Indexed: 12/17/2022]
Abstract
Long-chain nonesterified ("free") fatty acids (FFA) and some of their derivatives and metabolites can modify intracellular production of reactive oxygen species (ROS), in particular O(2)(-) and H(2)O(2). In mitochondria, FFA exert a dual effect on ROS production. Because of slowing down the rate of electron flow through Complexes I and III of the respiratory chain due to interaction within the complex subunit structure, and between Complexes III and IV due to release of cytochrome c from the inner membrane, FFA increase the rate of ROS generation in the forward mode of electron transport. On the other hand, due to their protonophoric action on the inner mitochondrial membrane ("mild uncoupling effect"), FFA strongly decrease ROS generation in the reverse mode of electron transport. In the plasma membrane of phagocytic neutrophils and a number of other types of cells, polyunsaturated FFA stimulate O(2)(-) generation by NADPH oxidase. These effects of FFA can modulate signaling functions of ROS and be, at least partly, responsible for their proapoptotic effects in several types of cells.
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Affiliation(s)
- Peter Schönfeld
- Institute of Biochemistry and Cell Biology, Otto von Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany.
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19
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Koshkin V, Dai FF, Robson-Doucette CA, Chan CB, Wheeler MB. Limited Mitochondrial Permeabilization Is an Early Manifestation of Palmitate-induced Lipotoxicity in Pancreatic β-Cells. J Biol Chem 2008; 283:7936-48. [DOI: 10.1074/jbc.m705652200] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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20
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Belyaeva EA, Dymkowska D, Wieckowski MR, Wojtczak L. Reactive oxygen species produced by the mitochondrial respiratory chain are involved in Cd2+-induced injury of rat ascites hepatoma AS-30D cells. BIOCHIMICA ET BIOPHYSICA ACTA 2006; 1757:1568-74. [PMID: 17069748 DOI: 10.1016/j.bbabio.2006.09.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 08/18/2006] [Accepted: 09/15/2006] [Indexed: 02/05/2023]
Abstract
Using AS-30D rat ascites hepatoma cells, we studied the modulating action of various antioxidants, inhibitors of mitochondrial permeability transition pore and inhibitors of the respiratory chain on Cd(2+)-produced cytotoxicity. It was found that Cd(2+) induced both necrosis and apoptosis in a time- and dose-dependent way. This cell injury involved dissipation of the mitochondrial transmembrane potential, respiratory dysfunction and initial increase of the generation of reactive oxygen species (ROS), followed by its decrease after prolonged incubation. Inhibitors of the mitochondrial permeability transition pore, cyclosporin A and bongkrekic acid, and inhibitors of respiratory complex III, stigmatellin and antimycin A, but not inhibitor of complex I, rotenone, partly prevented necrosis evoked by exposure of the cells to Cd(2+). Apoptosis of the cells was partly prevented by free radical scavengers and by preincubation with N-acetylcysteine. Stigmatellin, antimycin A and cyclosporin A also abolished Cd(2+)-induced increase in ROS generation. It is concluded that Cd(2+) toxicity in AS-30D rat ascites hepatoma, manifested by cell necrosis and/or apoptosis, involves ROS generation, most likely at the level of respiratory complex III, and is related to opening of the mitochondrial permeability transition pore.
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Affiliation(s)
- Elena A Belyaeva
- Nencki Institute of Experimental Biology, Pasteura 3, 02-093 Warsaw, Poland.
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21
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Schrader M, Fahimi HD. Peroxisomes and oxidative stress. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1755-66. [PMID: 17034877 DOI: 10.1016/j.bbamcr.2006.09.006] [Citation(s) in RCA: 516] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 09/05/2006] [Accepted: 09/06/2006] [Indexed: 12/28/2022]
Abstract
The discovery of the colocalization of catalase with H2O2-generating oxidases in peroxisomes was the first indication of their involvement in the metabolism of oxygen metabolites. In past decades it has been revealed that peroxisomes participate not only in the generation of reactive oxygen species (ROS) with grave consequences for cell fate such as malignant degeneration but also in cell rescue from the damaging effects of such radicals. In this review the role of peroxisomes in a variety of physiological and pathological processes involving ROS mainly in animal cells is presented. At the outset the enzymes generating and scavenging H2O2 and other oxygen metabolites are reviewed. The exposure of cultured cells to UV light and different oxidizing agents induces peroxisome proliferation with formation of tubular peroxisomes and apparent upregulation of PEX genes. Significant reduction of peroxisomal volume density and several of their enzymes is observed in inflammatory processes such as infections, ischemia-reperfusion injury and hepatic allograft rejection. The latter response is related to the suppressive effects of TNFalpha on peroxisomal function and on PPARalpha. Their massive proliferation induced by a variety of xenobiotics and the subsequent tumor formation in rodents is evidently due to an imbalance in the formation and scavenging of ROS, and is mediated by PPARalpha. In PEX5-/- mice with the absence of functional peroxisomes severe abnormalities of mitochondria in different organs are observed which resemble closely those in respiratory chain disorders associated with oxidative stress. Interestingly, no evidence of oxidative damage to proteins or lipids, nor of increased peroxide production has been found in that mouse model. In this respect the role of PPARalpha, which is highly activated in those mice, in prevention of oxidative stress deserves further investigation.
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Affiliation(s)
- Michael Schrader
- Department of Cell Biology and Cell Pathology, University of Marburg, Robert Koch Str. 6, 35037 Marburg, Germany.
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22
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De Lago E, Gustafsson SB, Fernández-Ruiz J, Nilsson J, Jacobsson SOP, Fowler CJ. Acyl-based anandamide uptake inhibitors cause rapid toxicity to C6 glioma cells at pharmacologically relevant concentrations. J Neurochem 2006; 99:677-88. [PMID: 16899063 DOI: 10.1111/j.1471-4159.2006.04104.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Compounds blocking the uptake of the endogenous cannabinoid anandamide (AEA) have been used to explore the functions of the endogenous cannabinoid system in the CNS both in vivo and in vitro. In this study, the effects of four commonly used acyl-based uptake inhibitors [N-(4-hydroxyphenyl)arachidonylamide (AM404), N-(4-hydroxy-2-methylphenyl) arachidonoyl amide (VDM11), (5Z,8Z,11Z,14Z)-N-(3-furanylmethyl)-5,8,11,14-eicosatetraenamide (UCM707) and (9Z)-N-[1-((R)-4-hydroxybenzyl)-2-hydroxyethyl]-9-octadecen-amide (OMDM2)] and the related compound arvanil on C6 glioma cell viability were investigated. All five compounds reduced the ability of the cells to accumulate calcein, reduced the total nucleic acid content and increased the activity of lactate dehydrogenase recovered in the cell medium. AM404 (10 microm) and VDM11 (10 microm) acted rapidly, reducing cell viability after 3 h of exposure when cell densities of 5,000 per well were used. In contrast, UCM707 (30 microm), OMDM2 (10 microm) and the related compound arvanil (10 microm) produced a more slowly developing effect on cell viability, although robust effects were seen after 6-9 h of exposure. At higher cell densities, the toxicities of AM404 and UCM707 were reduced. Comparison of the compounds with arachidonic acid, arachidonic acid methyl ester, AEA, arachidonoyl glycine and oleic acid suggested that the toxicity of the arachidonoyl-based compounds was related primarily to the acyl side-chain rather than the head group. A variety of pre-treatments blocking possible metabolic pathways and receptor targets were tested, but the only consistent protective treatment against the effects of these compounds was the antioxidant N-acetyl-L-cysteine. It is concluded that AM404, VDM11, UCM707 and OMDM2 produce a rapid loss of C6 glioma cell viability over the same concentration range as is required for the inhibition of AEA uptake in vitro, albeit with a longer latency. Such effects should be kept in mind when acyl-derived compounds are used to probe the function of the endocannabinoid system in the CNS, particularly in chronic administration protocols.
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Affiliation(s)
- Eva De Lago
- Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden
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