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Anticancer drugs tamoxifen and 4hydroxytamoxifen as effectors of phosphatidylethanolamine lipid polymorphism. Chem Phys Lipids 2022; 248:105239. [PMID: 36075353 DOI: 10.1016/j.chemphyslip.2022.105239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 08/31/2022] [Accepted: 09/01/2022] [Indexed: 01/25/2023]
Abstract
The interaction of tamoxifen (TMX) and its metabolite 4-hydroxytamoxifen (HTMX) with a biomimetic membrane model system composed of 1,2-dielaidoylphosphatidylethanolamine (DEPE) has been studied using a biophysical approach. Incorporation of TMX into DEPE bilayers gives rise to a progressive broadening of the Lβ/Lα phase transition and a downward temperature shift. The Lβ/Lα phase transition presents multiple endotherms, indicating a lateral segregation of TMX/DEPE domains within the plane of the bilayer. TMX and HTMX also widen and shift the Lα to hexagonal-HII transition toward lower values, the phase diagrams showing that both compounds facilitate formation of the HII phase. TMX increases motional disorder of DEPE acyl chains in the Lβ, Lα and HII phases, whereas the effect of HTMX is clearly different. In addition, neither TMX nor HTMX significantly perturb the hydration state of the polar headgroup region of DEPE. Molecular dynamics (MD) simulations indicate that these drugs do not affect membrane thickness, area per lipid, or the conformation of DEPE molecules. As a general rule, the interaction of HTMX with DEPE is qualitatively similar to TMX but less intense. However, a significant difference shown by MD is that HTMX is mainly placed around the center of each monolayer while TMX is located mainly at the center of the membrane, also having a greater tendency to cluster formation. These results are discussed to understand the modulation of phosphatidylethanolamine lipid polymorphism carried out by these drugs, which could be of relevance to explain their effects on enzyme activity or membrane permeabilization.
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2
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Optimization of nanoemulsified systems containing lamellar phases for co-delivery of celecoxib and endoxifen to the skin aiming for breast cancer chemoprevention and treatment. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128901] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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3
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Ortiz J, Aranda FJ, Teruel JA, Ortiz A. Dissimilar action of tamoxifen and 4-hydroxytamoxifen on phosphatidylcholine model membranes. Biophys Chem 2021; 278:106681. [PMID: 34530285 DOI: 10.1016/j.bpc.2021.106681] [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: 07/22/2021] [Revised: 09/03/2021] [Accepted: 09/06/2021] [Indexed: 11/19/2022]
Abstract
The anticancer drug tamoxifen and its primary metabolite 4-hydroxytamoxifen tend to accumulate in membranes due to its strong hydrophobic character. Thus, in this work we have carried out a systematic study to investigate their effects on model phosphatidylcholine membranes. Tamoxifen and 4-hydroxytamoxifen affect the phase behaviour of phosphatidylcholine model membranes, giving rise to formation of drug/dipalmitoylphosphatidylcholine domains, which is more evident in the case of 4-hydroxytamoxifen. These drugs have differential effects on the polar and apolar regions of the phospholipid supporting a different location of both compounds within the bilayer. Both compounds induce contents leakage in fluid phosphatidylcholine unilamellar liposomes, the effect of 4-hydroxytamoxifen being negligible as compared to that of tamoxifen. Molecular dynamics confirmed the tendency of both drugs to form clusters, tamoxifen locating all along the bilayer, whereas 4-hydroxytamoxifen mostly locates near the lipid/water interface, which can explain the different effects of both drugs in fluid phosphatidylcholine membranes.
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Affiliation(s)
- Julia Ortiz
- Departamento de Bioquímica y Biología Molecular-A, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, E-30100 Murcia, Spain
| | - Francisco J Aranda
- Departamento de Bioquímica y Biología Molecular-A, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, E-30100 Murcia, Spain
| | - José A Teruel
- Departamento de Bioquímica y Biología Molecular-A, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, E-30100 Murcia, Spain
| | - Antonio Ortiz
- Departamento de Bioquímica y Biología Molecular-A, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, E-30100 Murcia, Spain.
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4
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Famurewa AC, Ekeleme-Egedigwe CA, David EE, Eleazu CO, Folawiyo AM, Obasi NA. Zinc abrogates anticancer drug tamoxifen-induced hepatotoxicity by suppressing redox imbalance, NO/iNOS/NF-ĸB signaling, and caspase-3-dependent apoptosis in female rats. Toxicol Mech Methods 2020; 30:115-123. [PMID: 31532279 DOI: 10.1080/15376516.2019.1669243] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Tamoxifen (TAM) is used in breast cancer chemotherapy since its approval by the Food and Drug Administration in 1977. However, TAM therapy is accompanied with hepatotoxicity - a source of worry to clinicians. Oxidative stress and inflammation are the major implicated mechanisms contributing to TAM hepatotoxicity. In this study, we explored whether zinc (Zn) supplementation could prevent TAM-induced hepatotoxicity in female Wistar rats. Rats were subjected to oral pretreatment of Zn (100 mg/kg body weight (b.w.)/day) for 14 days against hepatic toxicity induced by single intraperitoneal administration of TAM (50 mg/kg b.w.) on day 13. TAM markedly elevated serum liver enzymes, whereas total protein and albumin considerably reduced. TAM caused prominent depletion of hepatic-reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activity. Also, TAM significantly increased malondialdehyde (MDA) level. Further, it raised liver levels of tumor necrosis factor-α (TNF-α), interleukin-1β, (IL-1β), interleukin-6 (IL-6), and nitric oxide (NO) confirmed by the liver histopathological alterations. The mechanistic inflammatory expression of inducible nitric oxide synthase (iNOS) and nuclear factor-kappa B (NF-ĸB), and expression of caspase-3 protein prominently increased. Zinc supplementation significantly modulated serum liver function markers, antioxidant enzymes, and GSH and MDA levels. Zinc downregulated the expression of cytokines, NO, iNOS, NF-ĸB and caspase-3, and ameliorated histopathological changes. Zinc protects against TAM-induced hepatotoxicity; it may serve as an adjuvant supplement for female patients undergoing TAM chemotherapy.
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Affiliation(s)
- Ademola C Famurewa
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, Alex Ekwueme Federal University, Ikwo, Nigeria
- Biochemistry Division, Amala Cancer Research Centre, Amala Institute of Medical Sciences, Thrissur, India
| | - Chima A Ekeleme-Egedigwe
- Department of Chemistry/Biochemistry and Molecular Biology, Faculty of Science, Alex-Ekwueme Federal University, Ikwo, Nigeria
| | - Ebuka E David
- Department of Chemistry/Biochemistry and Molecular Biology, Faculty of Science, Alex-Ekwueme Federal University, Ikwo, Nigeria
| | - Chinedum O Eleazu
- Department of Chemistry/Biochemistry and Molecular Biology, Faculty of Science, Alex-Ekwueme Federal University, Ikwo, Nigeria
- Department of Physiology, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
| | - Abiola M Folawiyo
- Department of Physiology, Faculty of Basic Medical Sciences, Ekiti State University, Ado-Ekiti, Nigeria
| | - Nwogo A Obasi
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, Alex Ekwueme Federal University, Ikwo, Nigeria
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5
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Theodossiou TA, Ali M, Grigalavicius M, Grallert B, Dillard P, Schink KO, Olsen CE, Wälchli S, Inderberg EM, Kubin A, Peng Q, Berg K. Simultaneous defeat of MCF7 and MDA-MB-231 resistances by a hypericin PDT-tamoxifen hybrid therapy. NPJ Breast Cancer 2019; 5:13. [PMID: 30993194 PMCID: PMC6458138 DOI: 10.1038/s41523-019-0108-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 03/20/2019] [Indexed: 12/11/2022] Open
Abstract
Currently the greatest challenge in oncology is the lack of homogeneity of the lesions where different cell components respond differently to treatment. There is growing consensus that monotherapies are insufficient to eradicate the disease and there is an unmet need for more potent combinatorial treatments. We have previously shown that hypericin photodynamic therapy (HYP-PDT) triggers electron transport chain (ETC) inhibition in cell mitochondria. We have also shown that tamoxifen (TAM) enhances cytotoxicity in cells with high respiration, when combined with ETC inhibitors. Herein we introduce a synergistic treatment based on TAM chemotherapy and HYP-PDT. We tested this novel combinatorial treatment (HYPERTAM) in two metabolically different breast cancer cell lines, the triple-negative MDA-MB-231 and the estrogen-receptor-positive MCF7, the former being quite sensitive to HYP-PDT while the latter very responsive to TAM treatment. In addition, we investigated the mode of death, effect of lipid peroxidation, and the effect on cell metabolism. The results were quite astounding. HYPERTAM exhibited over 90% cytotoxicity in both cell lines. This cytotoxicity was in the form of both necrosis and autophagy, while high levels of lipid peroxidation were observed in both cell lines. We, consequently, translated our research to an in vivo pilot study encompassing the MDA-MB-231 and MCF7 tumor models in NOD SCID-γ immunocompromised mice. Both treatment cohorts responded very positively to HYPERTRAM, which significantly prolonged mice survival. HYPERTAM is a potent, synergistic modality, which may lay the foundations for a novel, composite anticancer treatment, effective in diverse tumor types.
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Affiliation(s)
- Theodossis A. Theodossiou
- Department of Radiation Biology, Institute for Cancer Research, Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Muhammad Ali
- Department of Immunology, Institute for Cancer Research, Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Mantas Grigalavicius
- Department of Radiation Biology, Institute for Cancer Research, Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Beata Grallert
- Department of Radiation Biology, Institute for Cancer Research, Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Pierre Dillard
- Department of Cellular Therapy, Department of Oncology, Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Kay Oliver Schink
- Department of Molecular Cell Biology, Institute for Cancer Research, Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Cathrine E. Olsen
- Department of Radiation Biology, Institute for Cancer Research, Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Sébastien Wälchli
- Department of Cellular Therapy, Department of Oncology, Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Else Marit Inderberg
- Department of Cellular Therapy, Department of Oncology, Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Andreas Kubin
- PLANTA Naturstoffe Vertriebs GmbH, A-1120 Wien, Austria
| | - Qian Peng
- Department of Pathology, Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Kristian Berg
- Department of Radiation Biology, Institute for Cancer Research, Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
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Ali A, Abouleila Y, Shimizu Y, Hiyama E, Watanabe TM, Yanagida T, Germond A. Single-Cell Screening of Tamoxifen Abundance and Effect Using Mass Spectrometry and Raman-Spectroscopy. Anal Chem 2019; 91:2710-2718. [PMID: 30664349 DOI: 10.1021/acs.analchem.8b04393] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Monitoring drug uptake, its metabolism, and response on the single-cell level is invaluable for sustaining drug discovery efforts. In this study, we show the possibility of accessing the information about the aforementioned processes at the single-cell level by monitoring the anticancer drug tamoxifen using live single-cell mass spectrometry (LSC-MS) and Raman spectroscopy. First, we explored whether Raman spectroscopy could be used as a label-free and nondestructive screening technique to identify and predict the drug response at the single-cell level. Then, a subset of the screened cells was isolated and analyzed by LSC-MS to measure tamoxifen and its metabolite, 4-Hydroxytamoxifen (4-OHT) in a highly selective, sensitive, and semiquantitative manner. Our results show the Raman spectral signature changed in response to tamoxifen treatment which allowed us to identify and predict the drug response. Tamoxifen and 4-OHT abundances quantified by LSC-MS suggested some heterogeneity among single-cells. A similar phenomenon was observed in the ratio of metabolized to unmetabolized tamoxifen across single-cells. Moreover, a correlation was found between tamoxifen and its metabolite, suggesting that the drug was up taken and metabolized by the cell. Finally, we found some potential correlations between Raman spectral intensities and tamoxifen abundance, or its metabolism, suggesting a possible relationship between the two signals. This study demonstrates for the first time the potential of using Raman spectroscopy and LSC-MS to investigate pharmacokinetics at the single-cell level.
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Affiliation(s)
- Ahmed Ali
- Riken Biodynamics Research Center (BDR) , 6-2-3 Furuedai , Suita , Osaka 565-0874 , Japan.,Research Center , Misr International University , Cairo 19648 , Egypt
| | - Yasmine Abouleila
- Riken Biodynamics Research Center (BDR) , 6-2-3 Furuedai , Suita , Osaka 565-0874 , Japan.,Research Center , Misr International University , Cairo 19648 , Egypt
| | - Yoshihiro Shimizu
- Riken Biodynamics Research Center (BDR) , 6-2-3 Furuedai , Suita , Osaka 565-0874 , Japan
| | - Eiso Hiyama
- Graduate School of Biomedical and Health Sciences , 1-2-3 Kasumi , Hiroshima , 734-0037 , Japan
| | - Tomonobu M Watanabe
- Riken Biodynamics Research Center (BDR) , 6-2-3 Furuedai , Suita , Osaka 565-0874 , Japan
| | - Toshio Yanagida
- Riken Biodynamics Research Center (BDR) , 6-2-3 Furuedai , Suita , Osaka 565-0874 , Japan
| | - Arno Germond
- Riken Biodynamics Research Center (BDR) , 6-2-3 Furuedai , Suita , Osaka 565-0874 , Japan
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7
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Theodossiou TA, Wälchli S, Olsen CE, Skarpen E, Berg K. Deciphering the Nongenomic, Mitochondrial Toxicity of Tamoxifens As Determined by Cell Metabolism and Redox Activity. ACS Chem Biol 2016; 11:251-62. [PMID: 26569462 DOI: 10.1021/acschembio.5b00734] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Tamoxifen is not only considered a very potent chemotherapeutic adjuvant for estrogen receptor positive breast cancers but also a very good chemo-preventive drug. Recently, there has been a rising amount of evidence for a nongenomic cytotoxicity of tamoxifen, even in estrogen receptor negative cells, which has greatly confounded researchers. Clinically, the side effects of tamoxifen can be very serious, ranging from liver steatosis to cirrhosis, tumorigenesis, or onset of porphyrias. Herein, we deciphered the nongenomic, mitochondrial cytotoxicity of tamoxifen in estrogen receptor positive MCF7 versus triple-negative MDA-MB-231 cells, employing the mitochondrial complex III quinoloxidizing-center inhibitor myxothiazol. We showed a role for hydroxyl-radical-mediated lipid peroxidation, catalyzed by iron, stemming from the redox interactions of tamoxifen quinoid metabolites with complex III, resulting in Fenton-capable reduced quinones. The role of tamoxifen semiquinone species in mitochondrial toxicity was also shown together with evidence of mitochondrial DNA damage. Tamoxifen caused an overall metabolic (respiratory and glycolytic) rate decrease in the Pasteur type MCF cells, while in the Warburg type MDA-MB-231 cells the respiratory rate was not significantly affected and the glycolytiv rate was significantly boosted. The nongenomic cytotoxicity of tamoxifens was hence associated with the metabolic phenotype and redox activity of the cells, as in the present paradigm of Pasteur MCF7s versus Warburg MDA-MB-231 cells. Our present findings call for caution in the use of the drugs, especially as a chemopreventive and/or in cases of iron overload diseases.
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Affiliation(s)
- Theodossis Athanassios Theodossiou
- Department
of Radiation Biology, Institute for Cancer Research, The Radium Hospital, Oslo University Hospital, Montebello, Oslo 0379, Norway
| | - Sébastien Wälchli
- Department
of Cancer Immunology, Institute for Cancer Research, and Department
for Cellular Therapy, The Radium Hospital, Oslo University Hospital, Montebello, Oslo 0379, Norway
| | - Cathrine Elisabeth Olsen
- Department
of Radiation Biology, Institute for Cancer Research, The Radium Hospital, Oslo University Hospital, Montebello, Oslo 0379, Norway
| | - Ellen Skarpen
- Department
of Molecular Cell Biology, Institute for Cancer Research, The Radium
Hospital, Oslo University Hospital, Montebello, Oslo 0379, Norway
| | - Kristian Berg
- Department
of Radiation Biology, Institute for Cancer Research, The Radium Hospital, Oslo University Hospital, Montebello, Oslo 0379, Norway
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Nada EA, El Taieb MA, Ibrahim HM, Al Saied AERA. Efficacy of tamoxifen andl-carnitine on sperm ultrastructure and seminal oxidative stress in patients with idiopathic oligoasthenoteratozoospermia. Andrologia 2014; 47:801-10. [DOI: 10.1111/and.12333] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2014] [Indexed: 01/04/2023] Open
Affiliation(s)
- E. A. Nada
- Department of Dermatology, Venereology and Andrology; Aswan Faculty of Medicine; Aswan University; Aswan Egypt
| | - M. A. El Taieb
- Department of Dermatology, Venereology and Andrology; Qina Faculty of Medicine; South Valley University; Qina Egypt
| | - H. M. Ibrahim
- Department of Dermatology, Venereology and Andrology; Qina Faculty of Medicine; South Valley University; Qina Egypt
| | - A. E.-R. A. Al Saied
- Department of Clinical Pathology; Qina Faculty of Medicine; South Valley University; Qina Egypt
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9
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Ribeiro MPC, Santos AE, Custódio JBA. Mitochondria: the gateway for tamoxifen-induced liver injury. Toxicology 2014; 323:10-8. [PMID: 24881593 DOI: 10.1016/j.tox.2014.05.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 05/14/2014] [Accepted: 05/28/2014] [Indexed: 12/13/2022]
Abstract
Tamoxifen (TAM) is routinely used in the treatment of breast carcinoma. TAM-induced liver injury remains a major concern, as TAM causes hepatic steatosis in a significant number of patients, which can progress toward steatohepatitis. Liver toxicity is generally believed to involve mitochondrial dysfunction and TAM exerts multiple deleterious effects on mitochondria, which may account for the hepatotoxicity observed in patients treated with TAM. Endoxifen (EDX), a key active metabolite of TAM that is being investigated as an alternative to TAM in breast cancer therapy, slightly affects mitochondria in comparison with TAM and this demonstration well correlates with the absence of alterations in the clinical parameters of individuals taking EDX. The steady-state plasma concentrations of TAM and its active metabolites EDX and 4-hydroxytamoxifen (OHTAM) in patients taking TAM are highly variable, reflecting genetic variants of CYP2D6 involved in TAM metabolism. Besides de genetic polymorphisms, the intake of drugs that influence the enzymatic activity of CYP2D6 compromises the therapeutic efficiency of TAM. The knowledge of the impact of the variability of TAM metabolism in the breast cancer treatment explains the discrepant outcomes observed in patients taking TAM, as well as the individual variability of idiosyncratic liver injury and other sides effects observed. Therefore, and contrarily to the clinical use of EDX, the need of therapeutic drug monitoring and a regular assessment of liver function biomarkers should be considered in patients under therapies with TAM. In this review we focus on the mitochondrial effects of TAM and its metabolites and on the role played by mitochondria in the initiating events leading to TAM-induced hepatotoxicity, as well as the clinical implications.
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Affiliation(s)
- Mariana P C Ribeiro
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra, Portugal; Laboratory of Biochemistry, Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Armanda E Santos
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra, Portugal; Laboratory of Biochemistry, Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - José B A Custódio
- Center for Neuroscience and Cell Biology, University of Coimbra, 3000-354 Coimbra, Portugal; Laboratory of Biochemistry, Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal.
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Combination therapy with tamoxifen and amphotericin B in experimental cutaneous leishmaniasis. Antimicrob Agents Chemother 2014; 58:2608-13. [PMID: 24550333 DOI: 10.1128/aac.01315-13] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Leishmaniasis chemotherapy remains very challenging. The high cost of active drugs, along with the severity of their side effects and the increasing failure rate of the current therapeutic schemes, calls for the discovery of new active drugs and schemes of treatment. The use of combination therapy has gained much attention in recent years as a possible strategy for overcoming the various shortcomings in the present arsenal. We recently described the effectiveness of tamoxifen in murine models of leishmaniasis, and here, we investigated the interactions between tamoxifen and amphotericin B, one of the most potent drugs used in leishmaniasis treatment. The in vitro interactions were indifferent for the association of tamoxifen and amphotericin B. The association was also assayed in vivo in Leishmania amazonensis-infected BALB/c mice and was found to yield at least additive effects at low doses of both drugs.
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11
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Ribeiro MP, Santos AE, Santos MS, Custódio JB. Effects of all-trans-retinoic acid on the permeability transition and bioenergetic functions of rat liver mitochondria in combination with endoxifen. Life Sci 2013; 93:96-107. [DOI: 10.1016/j.lfs.2013.05.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 05/09/2013] [Accepted: 05/29/2013] [Indexed: 11/26/2022]
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12
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Ribeiro MP, Silva FS, Santos AE, Santos MS, Custódio JB. The antiestrogen endoxifen protects rat liver mitochondria from permeability transition pore opening and oxidative stress at concentrations that do not affect the phosphorylation efficiency. Toxicol Appl Pharmacol 2013; 267:104-12. [DOI: 10.1016/j.taap.2012.12.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 11/30/2012] [Accepted: 12/03/2012] [Indexed: 12/18/2022]
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13
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The effect of the anticancer drugs tamoxifen and hydroxytamoxifen on the calcium pump of isolated sarcoplasmic reticulum vesicles. Toxicol In Vitro 2012; 10:523-31. [PMID: 20650233 DOI: 10.1016/s0887-2333(96)00040-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/1996] [Indexed: 11/24/2022]
Abstract
The interactions of tamoxifen (TAM) and its active metabolite 4-hydroxytamoxifen (OHTAM) with the sarcoplasmic reticulum (SR) Ca(2+)-pump were investigated. The turnover of the Ca(2+)-ATPase is strongly inhibited by both drugs at low concentrations that do not significantly perturb the lipid organization of SR membranes. Moreover, TAM decreases Ca(2+) accumulation by SR Ca(2+)-ATPase and increases in parallel the ATP hydrolysis, decreasing the energetic efficiency of the Ca(2+)-pump (Ca (2+)ATP coupling ratio) by about 70% at 30 muM. This uncoupling of ATP hydrolysis from Ca(2+) accumulation is a putative consequence of structural defects induced on membranes, since the ATP hydrolysis at low residual Ca(2+) (Ca(2+) not supplemented) is also stimulated. On the other hand, OHTAM decreases the Ca(2+) uptake to a greater extent than TAM but, unlike TAM, it inhibits ATP hydrolysis. Thus, the Ca (2+)ATP ratio is decreased by about 47% at 30 muM OHTAM; this effect is not a consequence of membrane disruption, since the ATP-splitting activity decreases in parallel to Ca(2+) accumulation and no significant effect is detected for ATP hydrolysis at low residual Ca(2+). The inhibition of the Ca(2+)-pump by OHTAM is putatively related to a direct interaction with the regulatory sites of the enzyme or interactive perturbations at the lipid-protein interface. The effect may result from a decrease of efficiency in the energy transmission and transduction between the ATP use at the catalytic site and the channeling process involved in Ca(2+) translocation. Therefore, the effects of the drugs on the Ca(2+)-pump are different and rule out an unitary mechanism of action on the basis of bilayer structure perturbations.
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14
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Oldham ED, Xie W, Farnoud AM, Fiegel J, Lehmler HJ. Disruption of phosphatidylcholine monolayers and bilayers by perfluorobutane sulfonate. J Phys Chem B 2012; 116:9999-10007. [PMID: 22834732 PMCID: PMC3464004 DOI: 10.1021/jp304412p] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Perfluoroalkyl acids (PFAAs) are persistent environmental contaminants resistant to biological and chemical degradation due to the presence of carbon-fluorine bonds. These compounds exhibit developmental toxicity in vitro and in vivo. The mechanisms of toxicity may involve partitioning into lipid bilayers. We investigated the interaction between perfluorobutane sulfonate (PFBS), an emerging PFAA, and model phosphatidylcholine (PC) lipid assemblies (i.e., dimyristoyl-, dipalmitoyl- and distearoylphosphatidylcholine) using fluorescence anisotropy and Langmuir monolayer techniques. PFBS decreased the transition temperature and transition width of PC bilayers. The apparent membrane partition coefficients ranged from 4.9 × 10(2) to 8.2 × 10(2). The effects on each PC were comparable. The limiting molecular area of PC monolayers increased, and the surface pressure at collapse decreased in a concentration-dependent manner. The compressibility of all three PCs was decreased by PFBS. In summary, PFBS disrupted different model lipid assemblies, indicating potential for PFBS to be a human toxicant. However, the effects of PFBS are not as pronounced as those seen with longer chain PFAAs.
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Affiliation(s)
- E. Davis Oldham
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa 52242
| | - Wei Xie
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa 52242
| | - Amir M. Farnoud
- Department of Chemical and Biochemical Engineering, College of Engineering, University of Iowa, Iowa City, Iowa, 52242
| | - Jennifer Fiegel
- Department of Chemical and Biochemical Engineering, College of Engineering, University of Iowa, Iowa City, Iowa, 52242
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, Iowa 52242
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa 52242
- Interdisciplinary Graduate Program in Human Toxicology, University of Iowa, Iowa City, Iowa 52242
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15
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Theodossiou TA, Yannakopoulou K, Aggelidou C, Hothersall JS. Tamoxifen subcellular localization; observation of cell-specific cytotoxicity enhancement by inhibition of mitochondrial ETC complexes I and III. Photochem Photobiol 2012; 88:1016-22. [PMID: 22428931 DOI: 10.1111/j.1751-1097.2012.01144.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Recently, a nongenomic cytotoxic component of the chemotherapeutic agent tamoxifen (TAM) has been identified that predominantly triggers mitochondrial events. The present study delineates the intracellular fate of TAM and studies its interaction with a spectrum of cell homeostasis modulators primarily relevant to mitochondria. The subcellular localization of TAM was assessed by confocal fluorescence microscopy. The effect of the modulators on TAM cytotoxicity was assessed by standard MTT assays. Our findings show that in estrogen receptor positive MCF7 breast adenocarcinoma cells and DU145 human prostate cancer cells, TAM largely accumulates in the mitochondria and endoplasmic reticulum, but not lysosomes. Our results further demonstrate that in MCF7, but not in DU145 cells, mitochondrial electron transport chain complex I and III inhibitors exacerbate TAM toxicity with an order of potency of myxothiazol ≥ stigmatellin > rotenone > antimycin A, suggesting a cell-specific cytotoxic interplay between mitochondrial complex I and III function and TAM action.
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16
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de Oliveira AC, Hillard EA, Pigeon P, Rocha DD, Rodrigues FA, Montenegro RC, Costa-Lotufo LV, Goulart MO, Jaouen G. Biological evaluation of twenty-eight ferrocenyl tetrasubstituted olefins: Cancer cell growth inhibition, ROS production and hemolytic activity. Eur J Med Chem 2011; 46:3778-87. [DOI: 10.1016/j.ejmech.2011.05.043] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Revised: 05/17/2011] [Accepted: 05/18/2011] [Indexed: 11/30/2022]
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17
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The antimalarial drug mefloquine inhibits cardiac inward rectifier K+ channels: evidence for interference in PIP2-channel interaction. J Cardiovasc Pharmacol 2011; 57:407-15. [PMID: 21502926 DOI: 10.1097/fjc.0b013e31820b7c03] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The antimalarial drug mefloquine was found to inhibit the KATP channel by an unknown mechanism. Because mefloquine is a Cationic amphiphilic drug and is known to insert into lipid bilayers, we postulate that mefloquine interferes with the interaction between PIP2 and Kir channels resulting in channel inhibition. We studied the inhibitory effects of mefloquine on Kir2.1, Kir2.3, Kir2.3(I213L), and Kir6.2/SUR2A channels expressed in HEK-293 cells, and on IK1 and IKATP from feline cardiac myocytes. The order of mefloquine inhibition was Kir6.2/SUR2A ≈ Kir2.3 (IC50 ≈ 2 μM) > Kir2.1 (IC50 > 30 μM). Similar results were obtained in cardiac myocytes. The Kir2.3(I213L) mutant, which enhances the strength of interaction with PIP2 (compared to WT), was significantly less sensitive (IC50 = 9 μM). In inside-out patches, continuous application of PIP2 strikingly prevented the mefloquine inhibition. Our results support the idea that mefloquine interferes with PIP2-Kir channels interactions.
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Darvari R, Boroujerdi M. Concentration dependency of modulatory effect of amlodipine on P-glycoprotein efflux activity of doxorubicin — a comparison with tamoxifen. J Pharm Pharmacol 2010; 56:985-91. [PMID: 15285842 DOI: 10.1211/0022357043941] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Modulators of P-glycoprotein (P-gp) can enhance or limit the permeability of a number of therapeutic agents that are considered substrates of this efflux pump protein. The modulatory effect of amlodipine (4-dihydropyridine calcium antagonist) on P-gp efflux activity has not been fully elucidated. We have studied the concentration dependency of its modulatory effect and compared it qualitatively with tamoxifen (a non-esteroid anti-estrogen). The investigation was conducted on transmembrane efflux of doxorubicin at a fixed concentration of 5 μm across a Caco-2 monolayer in the presence of various concentrations of amlodipine or tamoxifen. The maximum flux of doxorubicin from basolateral to apical (ba) occurred at 4.5 μm amlodipine and at 0.02 μm tamoxifen. At higher concentrations, the apical to basolateral (ab) flux and the net flux of doxorubicin (ba — ab) declined steadily in a concentration-dependent manner. We analysed the observed net flux data by fitting different mathematical models to the data. A composite sigmoidal Emax/Imax (stimulatory/inhibitory) model was found to be the most appropriate to define the system. The observed and calculated parameters supported the modulatory role of both compounds and clearly indicated that the stimulation and inhibition of transmembrane efflux occurred simultaneously in the presence of amlodipine or tamoxifen. It was concluded that amlodipine, similar to tamoxifen, modulated the transporter-dependent transmembrane flux of the P-gp substrate in a concentration-dependent manner.
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Affiliation(s)
- Ramin Darvari
- Epic Therapeutics Inc., 220 Norwood Park South, Norwood, MA 02062, USA
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19
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Xie W, Bothun GD, Lehmler HJ. Partitioning of perfluorooctanoate into phosphatidylcholine bilayers is chain length-independent. Chem Phys Lipids 2010; 163:300-8. [PMID: 20096277 DOI: 10.1016/j.chemphyslip.2010.01.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 01/04/2010] [Accepted: 01/08/2010] [Indexed: 11/30/2022]
Abstract
The chain length dependence of the interaction of PFOA, a persistent environmental contaminant, with dimyristoyl- (DMPC), dipalmitoyl- (DPPC) and distearoylphosphatidylcholine (DSPC) was investigated using steady-state fluorescence anisotropy spectroscopy, differential scanning calorimetry (DSC) and dynamic light scattering (DLS). PFOA caused a linear depression of the main phase transition temperature T(m) while increasing the width of the phase transition of all three phosphatidylcholines. Although PFOA's effect on T(m) and the transition width decreased in the order DMPC>DPPC>DSPC, its relative effect on the phase behavior was largely independent of the phosphatidylcholine. PFOA caused swelling of DMPC but not DPPC and DSPC liposomes at 37 degrees C in the DLS experiments, which suggests that PFOA partitions more readily into bilayers in the fluid phase. These findings suggest that PFOA's effect on the phase behavior of phosphatidylcholines depends on the cooperativity and state (i.e., gel versus liquid phase) of the membrane. DLS experiments are also consistent with partial liposome solubilization at PFOA/lipid molar ratios>1, which suggests the formation of mixed PFOA-lipid micelles.
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Affiliation(s)
- Wei Xie
- Department of Occupational and Environmental Health, University of Iowa, College of Public Health, Iowa City, IA 52242-5000, USA
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20
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Ponce-Balbuena D, López-Izquierdo A, Ferrer T, Rodríguez-Menchaca AA, Aréchiga-Figueroa IA, Sánchez-Chapula JA. Tamoxifen inhibits inward rectifier K+ 2.x family of inward rectifier channels by interfering with phosphatidylinositol 4,5-bisphosphate-channel interactions. J Pharmacol Exp Ther 2009; 331:563-73. [PMID: 19654266 DOI: 10.1124/jpet.109.156075] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tamoxifen, an estrogen receptor antagonist used in the treatment of breast cancer, inhibits the inward rectifier potassium current (I(K1)) in cardiac myocytes by an unknown mechanism. We characterized the inhibitory effects of tamoxifen on Kir2.1, Kir2.2, and Kir2.3 potassium channels that underlie cardiac I(K1). We also studied the effects of 4-hydroxytamoxifen and raloxifene. All three drugs inhibited inward rectifier K(+) 2.x (Kir2.x) family members. The order of inhibition for all three drugs was Kir2.3 > Kir2.1 approximately Kir2.2. The onset of inhibition of Kir2.x current by these compounds was slow (T(1/2) approximately 6 min) and only partially recovered after washout ( approximately 30%). Kir2.x inhibition was concentration-dependent but voltage-independent. The time course and degree of inhibition was independent of external or internal drug application. We tested the hypothesis that tamoxifen interferes with the interaction between the channel and the membrane-delimited channel activator, phosphatidylinositol 4,5-bisphosphate (PIP(2)). Inhibition of Kir2.3 currents was significantly reduced by a single point mutation of I213L, which enhances Kir2.3 interaction with membrane PIP(2). Pretreatment with PIP(2) significantly decreased the inhibition induced by tamoxifen, 4-hydroxytamoxifen, and raloxifene on Kir2.3 channels. Pretreatment with spermine (100 microM) decreased the inhibitory effect of tamoxifen on Kir2.1, probably by strengthening the channel's interaction with PIP(2). In cat atrial and ventricular myocytes, 3 microM tamoxifen inhibited I(K1), but the effect was greater in the former than the latter. The data strongly suggest that tamoxifen, its metabolite, and the estrogen receptor inhibitor raloxifene inhibit Kir2.x channels indirectly by interfering with the interaction between the channel and PIP(2).
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Affiliation(s)
- Daniela Ponce-Balbuena
- Unidad de Investigación Carlos Méndez del Centro Universitario de Investigaciones Biomédicas de la Universidad de Colima, Colima, Colima, México
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21
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Albukhari AA, Gashlan HM, El-Beshbishy HA, Nagy AA, Abdel-Naim AB. Caffeic acid phenethyl ester protects against tamoxifen-induced hepatotoxicity in rats. Food Chem Toxicol 2009; 47:1689-95. [DOI: 10.1016/j.fct.2009.04.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 04/04/2009] [Accepted: 04/16/2009] [Indexed: 10/20/2022]
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22
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Beca S, Pavlov E, Kargacin ME, Aschar-Sobbi R, French RJ, Kargacin GJ. Inhibition of a cardiac sarcoplasmic reticulum chloride channel by tamoxifen. Pflugers Arch 2008; 457:121-35. [PMID: 18458943 DOI: 10.1007/s00424-008-0510-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Revised: 03/21/2008] [Accepted: 03/25/2008] [Indexed: 11/25/2022]
Abstract
Anion and cation channels present in the sarcoplasmic reticulum (SR) are believed to be necessary to maintain the electroneutrality of SR membrane during Ca(2+) uptake by the SR Ca(2+) pump (SERCA). Here we incorporated canine cardiac SR ion channels into lipid bilayers and studied the effects of tamoxifen and other antiestrogens on these channels. A Cl(-) channel was identified exhibiting multiple subconductance levels which could be divided into two primary conductance bands. Tamoxifen decreases the time the channel spends in its higher, voltage-sensitive band and the mean channel current. The lower, voltage-insensitive, conductance band is not affected by tamoxifen, nor is a K(+) channel present in the cardiac SR preparation. By examining SR Ca(2+) uptake, SERCA ATPase activity, and SR ion channels in the same preparation, we also estimated SERCA transport current, SR Cl(-) and K(+) currents, and the density of SERCA, Cl(-), and K(+) channels in cardiac SR membranes.
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Affiliation(s)
- Sanja Beca
- Department of Physiology and Biophysics, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
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23
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Parvez S, Tabassum H, Banerjee BD, Raisuddin S. Taurine Prevents Tamoxifen-Induced Mitochondrial Oxidative Damage in Mice. Basic Clin Pharmacol Toxicol 2008; 102:382-7. [DOI: 10.1111/j.1742-7843.2008.00208.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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24
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Tabassum H, Parvez S, Rehman H, Banerjee BD, Raisuddin S. Catechin as an antioxidant in liver mitochondrial toxicity: Inhibition of tamoxifen-induced protein oxidation and lipid peroxidation. J Biochem Mol Toxicol 2007; 21:110-7. [PMID: 17623883 DOI: 10.1002/jbt.20167] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Tamoxifen (TAM) is a nonsteroidal triphenylethylene antiestrogenic drug widely used in the treatment and prevention of breast cancer. TAM brings about a collapse of the mitochondrial membrane potential. It acts both as an uncoupling agent and as a powerful inhibitor of mitochondrial electron transport chain. The effect of catechin pretreatment on the mitochondrial toxicity of TAM was studied in liver mitochondria of Swiss albino mice. TAM treatment caused a significant increase in the mitochondrial lipid peroxidation (LPO) and the protein carbonyls (PCs). It also caused a significant increase in superoxide radical production. Pretreatment of mice with catechin (40 mg/kg) showed significant protection as demonstrated by marked attenuation of increased oxidative stress parameters such LPO, PCs, and superoxide production. It also restored the decreased nonenzymatic and enzymatic antioxidants of mitochondria. The inhibitory effect of catechin on TAM-:induced oxidative damage suggests that it may have potential benefits in prevention of human diseases where reactive oxygen species have some role as causative agents.
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Affiliation(s)
- Heena Tabassum
- Immunotoxicology Laboratory, Department of Medical Elementology and Toxicology, Jamia Hamdard (Hamdard University), New Delhi 110 062, India
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25
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Moreira PI, Custódio JB, Oliveira CR, Santos MS. Hydroxytamoxifen protects against oxidative stress in brain mitochondria. Biochem Pharmacol 2004; 68:195-204. [PMID: 15183131 DOI: 10.1016/j.bcp.2004.03.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2004] [Accepted: 03/19/2004] [Indexed: 11/18/2022]
Abstract
This study evaluated the effect of hydroxytamoxifen, the major active metabolite of tamoxifen (synthetic, nonsteroidal antiestrogen drug), on the function of brain mitochondria. We observed that only high concentrations of hydroxytamoxifen (60 nmol/mg protein) induced a significant decrease in RCR, while ADP/O ratio remained statistically unchanged. Similarly, only the highest concentration of hydroxytamoxifen (60 nmol/mg protein) affected the phosphorylative capacity of brain mitochondria, characterized by a decrease in the repolarization level and an increase in the repolarization lag phase. We observed that all the concentrations of hydroxytamoxifen tested (7.5, 15 and 30 nmol/mg protein) prevented lipid peroxidation induced by the oxidant pair ADP/Fe(2+). Furthermore, through the analyses of calcium fluxes and mitochondrial transmembrane potential parameters, we observed that hydroxytamoxifen (30 nmol/mg protein) exerted some protection against pore opening, although in a less extension than that promoted by cyclosporin A, the specific inhibitor of the mitochondrial permeability transition pore. However, in the presence of hydroxytamoxifen plus cyclosporin A, the protection observed was significantly higher when compared with that induced by both agents alone. These results support the idea that hydroxytamoxifen protects lipid peroxidation and inhibits the mitochondrial permeability transition pore in brain. Since numerous neurodegenerative diseases are intimately related with mitochondrial dysfunction resulting from lipid peroxidation and induction of mitochondrial permeability transition, among other factors, future therapeutical strategies could be designed taking in account this neuroprotective role of hydroxytamoxifen, which is pharmacologically much more potent and less toxic than its promoter tamoxifen.
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Affiliation(s)
- Paula I Moreira
- Centre for Neuroscience of Coimbra, University Coimbra, Coimbra, Portugal
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26
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Monteiro JP, Martins JD, Luxo PC, Jurado AS, Madeira VMC. Molecular mechanisms of the metabolite 4-hydroxytamoxifen of the anticancer drug tamoxifen: use of a model microorganism. Toxicol In Vitro 2003; 17:629-34. [PMID: 14599455 DOI: 10.1016/s0887-2333(03)00111-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A strain of the thermophilic eubacterium Bacillus stearothermophilus was used as a model system to identify membrane mediated cytotoxic effects of 4-hydroxytamoxifen, following previous studies with tamoxifen. With this experimental approach we attempted to further clarify tamoxifen and 4-hydroxytamoxifen membrane interactions often evoked as responsible for their multiple cellular effects. Bacterial growth and the oxygen consumption rate provided quantitative data of the cytotoxic action of hydroxytamoxifen. The effects of hydroxytamoxifen on the physical properties of bacterial lipid membrane preparations were also evaluated by fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene. Cultures of B. stearothermophilus grown in a complex medium containing hydroxytamoxifen in the concentration range of 1 to 7 microM exhibited progressively longer lag adapting periods, decreased specific growth rates and lower growth yields, as compared to control cultures. Hydroxytamoxifen also affected the electron redox flow of B. stearothermophilus protoplasts and induced significant perturbation of the structural order of bacterial lipid dispersions. We concluded that the bacterial model provides useful information about the nature and repercussion of membrane physical interactions of this lipophilic drug, on the basis of an easy and economic methodology.
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Affiliation(s)
- J P Monteiro
- Centro de Neurociências, Universidade de Coimbra, 3000 Coimbra, Portugal
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27
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He J, Kargacin ME, Kargacin GJ, Ward CA. Tamoxifen inhibits Na+ and K+ currents in rat ventricular myocytes. Am J Physiol Heart Circ Physiol 2003; 285:H661-8. [PMID: 12702490 DOI: 10.1152/ajpheart.00686.2002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tamoxifen is an estrogen receptor antagonist used in the treatment of breast cancer. However, tamoxifen has been shown to induce QT prolongation of the electrocardiogram, thereby potentially causing life-threatening polymorphic ventricular arrhythmias. The purpose of the present study was to elucidate the electrophysiological mechanism(s) that underlie the arrhythmogenic effects of tamoxifen. We used standard ruptured whole cell and perforated patch-clamping techniques on rat ventricular myocytes to investigate the effects of tamoxifen on cardiac action potential (AP) waveforms and the underlying K+ currents. Tamoxifen (3 micromol/l) markedly prolonged AP duration, decreased maximal rate of depolarization, and decreased resting membrane potential. At this concentration, tamoxifen significantly depressed the Ca2+-independent transient outward K+ current (Ito), sustained outward delayed rectifier K+ current (Isus), inward rectifier K+ current (IK1), and Na+ current (INa) in the myocytes. Lower concentrations of tamoxifen (1 micromol/l) also decreased the resting membrane potential and significantly depressed IK1 to 79 +/- 5% (n = 5; at -120 mV) of pretreatment values. The results of this study indicate that inhibition of Ito, Isus, and IK1 by tamoxifen may underlie AP prolongation in cardiac myocytes and thereby contribute to prolonged QT interval observed in patients.
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Affiliation(s)
- Jianying He
- Department of Physiology, Queen's University, Kingston, Ontario K7L 3N6, Canada
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28
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Cruz Silva MM, Madeira VM, Almeida LM, Custódio JB. Hydroxytamoxifen interaction with human erythrocyte membrane and induction of permeabilization and subsequent hemolysis. Toxicol In Vitro 2001; 15:615-22. [PMID: 11698160 DOI: 10.1016/s0887-2333(01)00079-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
4-Hydroxytamoxifen (OHTAM) is the most active metabolite of the widely prescribed anticancer drug tamoxifen (TAM) used in breast cancer therapy. This work describes the effects of OHTAM on isolated human erythrocytes, using standardized test conditions, to check for a putative contribution to the TAM-induced hemolysis and to study basic mechanisms involved in the interaction of OHTAM with cell membranes. Incubation of isolated human erythrocytes with relatively high concentrations of OHTAM results in a concentration-dependent hemolysis, its hemolytic effect being about one-third of that induced by TAM. OHTAM-induced hemolysis is prevented by either alpha-tocopherol (alpha-T) or alpha-tocopherol acetate (alpha-TAc) and it occurs in the absence of oxygen consumption and hemoglobin oxidation, ruling out the oxidative damage of erythrocytes. However, OHTAM remarkably increases the osmotic fragility of erythrocytes, increasing the susceptibility of erythrocytes to hypotonic lysis. Additionally, the hemoglobin release induced by OHTAM is preceded by a rapid efflux of intracellular K(+). Therefore, our data suggest that OHTAM-induced hemolysis does not contribute to TAM-induced hemolytic anemia and it is a much weaker toxic drug as compared with TAM. Moreover, at variance with the membrane disrupting effects of TAM, OHTAM promotes perturbation of the membrane's backbone region due to its strong binding to proteins with consequent formation of membrane paths of permeability to small solutes and retention of large solutes like hemoglobin, followed by osmotic swelling and cell lysis. The prevention of OHTAM-induced hemolysis by alpha-T and alpha-TAc is probably committed to the permeability sealing resulting from structural stabilization of membrane.
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Affiliation(s)
- M M Cruz Silva
- Laboratório de Bioquímica, Faculdade de Farmácia, 3000, Coiombra, Portugal
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29
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Dodds ML, Kargacin ME, Kargacin GJ. Effects of anti-oestrogens and beta-estradiol on calcium uptake by cardiac sarcoplasmic reticulum. Br J Pharmacol 2001; 132:1374-82. [PMID: 11264229 PMCID: PMC1572683 DOI: 10.1038/sj.bjp.0703924] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. Tamoxifen and a group of structurally similar non-steroidal, triphenolic compounds inhibit the oestrogen receptor. In addition to this action, these anti-oestrogens are known to inhibit some types of plasma membrane ion channels and other proteins through mechanisms that do not appear to involve their interactions with the estrogen receptor but could be the result of their effect on membrane lipid structure or fluidity. 2. We studied the effects of beta-estradiol and three anti-oestrogens (tamoxifen, 4-hydroxytamoxifen and clomiphene) on Ca(2+) uptake into sarcoplasmic reticulum (SR) vesicles isolated from canine cardiac ventricular tissue. 3. The antiestrogens all inhibit SR Ca(2+) uptake in a concentration-dependent manner (order of potency: tamoxifen > 4-hydroxytamoxifen > or = clomiphene). Although these compounds rapidly inhibit net Ca(2+) uptake they do not have a similar rapid effect on the ATPase activity of the SR Ca pump. beta-estradiol has no effect on Ca(2+) uptake nor does it alter the inhibitory action of tamoxifen on the SR. 4. The differences in the effects of beta-estradiol and the anti-oestrogens on cardiac SR Ca(2+) uptake do not correlate with differences in the ways in which these compounds have been reported to interact with membrane lipids. Our results are consistent, however, with direct effects on a membrane protein (possibly an SR Cl(-) or K(+) channel).
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Affiliation(s)
- Marnie L Dodds
- Smooth Muscle Research Group, Department of Physiology and Biophysics, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada, T2N 4N1
| | - Margaret E Kargacin
- Smooth Muscle Research Group, Department of Physiology and Biophysics, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada, T2N 4N1
| | - Gary J Kargacin
- Smooth Muscle Research Group, Department of Physiology and Biophysics, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada, T2N 4N1
- Author for correspondence:
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Faivre V, Rosilio V, Boullanger P, Almeida LM, Baszkin A. Fucosyled neoglycolipids: synthesis and interaction with a phospholipid. Chem Phys Lipids 2001; 109:91-101. [PMID: 11163347 DOI: 10.1016/s0009-3084(00)00219-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The interfacial behavior of the neoglycolipids formed of Guerbet alcohol (G(28)) bound to a triethylene glycol spacer (E(3)) and to a sugar moiety (alpha- and beta-fucose) spread at the air/water interface has been studied under dynamic conditions of compression. Although the alpha (alpha-FucE3G28)- and beta-fucose (beta-FucE3G28) derivatives possessed the same chemical structure, the positioning of the sugar moiety relative to the whole molecule had a significant influence on the organization of neoglycolipid molecules in the spread monolayers. Thus, beta-fucose molecules exhibited higher compressibilities and larger molecular areas than a alpha/beta (84/16%) mixture (alpha(84)-FucE3G28). The comparison of the compressional behavior of the fucose derivatives with that of Guerbet alcohol in the absence and in the presence of the triethylene glycol spacer shows that the presence of the E(3) chain is necessary to stabilize the lipid at the interface and that the incorporation of a sugar moiety into the molecule resulted in an important expansion of a monolayer. Despite their different interfacial behaviors, the two sugar derivatives formed ideal mixtures when cospread at the air/water interface. Conversely, in the presence of a phospholipid, such as DMPC, repulsive interactions were observed and appeared to be stronger for DMPC/alpha(84)-FucE3G28 mixed monolayers. The membrane fluidity of DMPC liposomes bearing the studied amphiphilic molecules was assessed by fluorescence depolarization measurements. The results reveal that whereas G(28) was deeply inserted into the liposome bilayers, the presence of a E(3) chain and of a sugar moiety in these bilayers induced a transfer of the amphiphilic derivatives from the hydrophobic core towards polar headgroups of phospholipid molecules.
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Affiliation(s)
- V Faivre
- Physico-Chimie des Surfaces, UMR CNRS 8612, Université Paris-Sud, 5 Rue J.B. Clément, 92296 Châtenay-Malabry Cedex, France
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31
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Cruz Silva MM, Madeira VM, Almeida LM, Custódio JB. Hemolysis of human erythrocytes induced by tamoxifen is related to disruption of membrane structure. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1464:49-61. [PMID: 10704919 DOI: 10.1016/s0005-2736(99)00237-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tamoxifen (TAM), the antiestrogenic drug most widely prescribed in the chemotherapy of breast cancer, induces changes in normal discoid shape of erythrocytes and hemolytic anemia. This work evaluates the effects of TAM on isolated human erythrocytes, attempting to identify the underlying mechanisms on TAM-induced hemolytic anemia and the involvement of biomembranes in its cytostatic action mechanisms. TAM induces hemolysis of erythrocytes as a function of concentration. The extension of hemolysis is variable with erythrocyte samples, but 12.5 microM TAM induces total hemolysis of all tested suspensions. Despite inducing extensive erythrocyte lysis, TAM does not shift the osmotic fragility curves of erythrocytes. The hemolytic effect of TAM is prevented by low concentrations of alpha-tocopherol (alpha-T) and alpha-tocopherol acetate (alpha-TAc) (inactivated functional hydroxyl) indicating that TAM-induced hemolysis is not related to oxidative membrane damage. This was further evidenced by absence of oxygen consumption and hemoglobin oxidation both determined in parallel with TAM-induced hemolysis. Furthermore, it was observed that TAM inhibits the peroxidation of human erythrocytes induced by AAPH, thus ruling out TAM-induced cell oxidative stress. Hemolysis caused by TAM was not preceded by the leakage of K(+) from the cells, also excluding a colloid-osmotic type mechanism of hemolysis, according to the effects on osmotic fragility curves. However, TAM induces release of peripheral proteins of membrane-cytoskeleton and cytosol proteins essentially bound to band 3. Either alpha-T or alpha-TAc increases membrane packing and prevents TAM partition into model membranes. These effects suggest that the protection from hemolysis by tocopherols is related to a decreased TAM incorporation in condensed membranes and the structural damage of the erythrocyte membrane is consequently avoided. Therefore, TAM-induced hemolysis results from a structural perturbation of red cell membrane, leading to changes in the framework of the erythrocyte membrane and its cytoskeleton caused by its high partition in the membrane. These defects explain the abnormal erythrocyte shape and decreased mechanical stability promoted by TAM, resulting in hemolytic anemia. Additionally, since membrane leakage is a final stage of cytotoxicity, the disruption of the structural characteristics of biomembranes by TAM may contribute to the multiple mechanisms of its anticancer action.
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Affiliation(s)
- M M Cruz Silva
- Laboratório de Bioquímica, Faculdade de Farmácia, Universidade de Coimbra, Couraça dos Apostolos, 51, r/c 3000, Coimbra, Portugal
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33
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Freund WD, Grieshop B, Neumann U, Reddig S. Glutamate-induced calcium responses in rat primary cortical cultures are potentiated by co-administration of glutamate transport inhibitors. Neurosci Lett 1995; 188:61-4. [PMID: 7783980 DOI: 10.1016/0304-3940(95)11395-d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effects of glutamate uptake inhibitors on the L-glutamate-induced increase in intracellular calcium concentrations were assessed in rat primary cortical cultures. The glutamate (10 microM)-induced rise in intracellular calcium concentrations was strongly and dose dependently increased and prolonged by simultaneous administration of micromolar concentrations of the reference glutamate transport inhibitors, L-trans-pyrrolidine-2,4-dicarboxylate (PDC) and D- or L-threo-beta-hydroxyaspartate. PDC in concentrations up to 10 microM showed no effect on intracellular calcium when administered alone. The anticancer drug tamoxifen, which was found to be effective as a glutamate transport inhibitor, did not increase but prolonged the cellular calcium response to glutamate, indicating that it had a different mechanism of action compared to that of standard glutamate transport inhibitors. The findings suggest that compounds which inhibit the glutamate transporter may potentiate the excitatory glutamatergic signal of cultured neurons when administered together with glutamate.
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Affiliation(s)
- W D Freund
- Institute for Neurobiology, Troponwerke GmbH & Co. KG, Köln, Germany
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Custódio JB, Dinis TC, Almeida LM, Madeira VM. Tamoxifen and hydroxytamoxifen as intramembraneous inhibitors of lipid peroxidation. Evidence for peroxyl radical scavenging activity. Biochem Pharmacol 1994; 47:1989-98. [PMID: 8010983 DOI: 10.1016/0006-2952(94)90073-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Tamoxifen (TAM) is the antiestrogen most widely used in the chemotherapy and chemoprevention of breast cancer. It has been reported that TAM and its more active metabolite 4-hydroxytamoxifen (OHTAM) induce multiple cellular effects, including antioxidant actions. Here sarcoplasmic reticulum membranes (SR) were used as a simple model of oxidation to clarify the antioxidant action type and mechanisms of these anticancer drugs on lipid peroxidation induced by Fe2+/ascorbate and peroxyl radicals generated by the water-soluble 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH) and by the lipid-soluble 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN). Peroxidation was monitored by different assay systems, namely cis-parinaric acid (PnA) fluorescence quenching, production of thiobarbituric acid-reactive substances, polyunsaturated fatty acids (PUFA) degradation and oxygen consumption. TAM and OHTAM are efficient inhibitors of lipid peroxidation induced by Fe2+/ascorbate and strong intramembraneous scavengers of peroxyl radicals generated either in the water or lipid phases by AAPH and AMVN, respectively. However, these drugs are not typical chain-breaking antioxidant compounds as compared with vitamin E. Additionally, their antioxidant effectiveness enhances the protective capacity of vitamin E against lipid peroxidation induced by AMVN. OHTAM is a more powerful intramembraneous inhibitor of lipid peroxidation as compared with TAM; this effectiveness not correlating with alterations on membrane fluidity may be due to the presence of a hydrogen-donating HO-group in the OHTAM molecule and its preferential location in the outer bilayer regions where it can donate the hydrogen atom to quench free radicals capable of initiating the membrane oxidative degradation. The stronger OHTAM intramembraneous scavenger capacity over TAM also correlates with its higher partition in biomembranes. Therefore, the strong peroxyl radical scavenger activity of OHTAM in the hydrophobic membrane phase may putatively contribute to the mechanisms of cytostatic and chemopreventive action of its promoter TAM on development of breast cancer.
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Affiliation(s)
- J B Custódio
- Laboratório de Bioquímica, Faculdade de Farmácia, Universidade de Coimbra, Portugal
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