Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-24T03:46:06.341Z Has data issue: false hasContentIssue false
  • English
  • Français

Comparison of the cytotoxic effects of β-sitosterol oxides and a cholesterol oxide, 7β-hydroxycholesterol, in cultured mammalian cells

Published online by Cambridge University Press:  09 March 2007

Lindsay Maguire ,
Mikhail Konoplyannikov ,
Alan Ford ,
Anita R. Maguire  and
Nora M. O'Brien
Lindsay Maguire
Affiliation:
Department of Food and Nutritional Sciences, University College, Cork, Republic of Ireland
Mikhail Konoplyannikov
Affiliation:
Department of Food and Nutritional Sciences, University College, Cork, Republic of Ireland
Alan Ford
Affiliation:
Department of Chemistry, Analytical and Biological Chemistry Research Facility, University College, Cork, Republic of Ireland
Anita R. Maguire
Affiliation:
Department of Chemistry, Analytical and Biological Chemistry Research Facility, University College, Cork, Republic of Ireland
Nora M. O'Brien*
Affiliation:
Department of Food and Nutritional Sciences, University College, Cork, Republic of Ireland
*
*Corresponding author: Dr Nora M. O'Brien, fax +353 21 4270244, email [email protected]
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Phytosterols are plant sterols found in foods such as oils, nuts and vegetables. Phytosterols, in the same way as cholesterol, contain a double bond and are susceptible to oxidation. The objective of the present study was to assess the potential toxic effects of β-sitosterol oxides on U937 cells. The effects of increasing concentrations (0-120 μM) of β-sitosterol oxides on cellular cytotoxicity, apoptosis, anti-oxidant status and genotoxicity was assessed over 12, 24 and 48h exposure periods. Following 12h, the viability of cells treated with 120 μM-β-sitosterol oxides was reduced to 51·7% relative to control. At 24 and 48 h, both 60 and 120 μM-β-sitosterol oxides caused a significant decrease in cell viability. For comparison, a decrease in viability of cells treated with a cholesterol oxide, 7β-hydroxycholesterol (7β-OH, 30 μM), was evident at 24 h. An increase in apoptotic cells, assessed using Hoechst 33342, indicates that the mode of cell death in U937 cells following exposure to 7β-OH (30 μM) and β-sitosterol oxides (60 and 120 μM) was by apoptosis. The increase in apoptotic cells after 12h following treatment with 120 μM-β-sitosterol oxides was accompanied by a decrease in cellular glutathione. Similarly, 7β-OH (30 μM) treatment resulted in decreased glutathione at 12 h. Catalase activity was not affected by any of the treatments. β-Sitosterol oxides had no genotoxic effects on U937 and V79 cells as assessed by the comet and sister chromatid exchange assays respectively. In general, the results indicate that thermally oxidised derivatives of β-sitosterol demonstrate similar biological effects as 7β-OH in U937 cells, but at higher concentrations.

Keywords

Phytosterol oxidesCholesterol oxidesCytotoxicityApoptosis
Type
Research Article
Information
British Journal of Nutrition , Volume 90 , Issue 4 , October 2003 , pp. 767 - 775
Copyright
Copyright © The Nutrition Society 2003

References

Adcox, C, Boyd, L, Oehrl, L, Allen, J & Fenner, G (2001) Comparative effects of phytosteroloxides and cholesterol oxides in cultured macrophage-derived cell lines. J Agric Food Chem 49, 2090–2095.CrossRefGoogle ScholarPubMed
Aupeix, K, Weltin, D, Mejia, JE, et al. (1995) Oxysterol-induced apoptosis in human monocytic cell lines. Immunobiology 194, 415–428.CrossRefGoogle ScholarPubMed
Baudhuin, P, Beaufay, H, Rahman-Li, Y, et al. (1964) Tissue fractionation studies. 17. Intracellular distribution of monoamine oxidase, aspartate aminotransferase, alanine aminotransferase, D-amino acid oxidase and catalase in rat-liver tissue. Biochem J 92, 179–184.CrossRefGoogle ScholarPubMed
Bjorkhem, I & Boberg, KM (1994) Inborn errors in bile acid biosynthesis and storage of sterols other than cholesterol. In The Metabolic Basis of Inherited Diseases, pp. 2073–2100 [Scriver,, CR, Beaudet,, AL, Sly, WSValle, D, editors]. New York, NY: McGraw Hill.Google Scholar
Cantwell, H & Devery, R (1998) The response of the antioxidant defense system in rat hepatocytes challenged with oxysterols is modified by Covi-ox. Cell Biol Toxicol 14, 401–409.CrossRefGoogle ScholarPubMed
Christ, M, Luu, B, Mejia, JE, Moosbrugger, I & Bischoff, P (1993) Apoptosis induced by oxysterols in murine lymphoma cells and in normal thymocytes. Immunobiology 78, 455–460.Google ScholarPubMed
Clare, K, Hardwick, SJ, Carpenter, KLH, Weeratunge, N & Mitchinson, MJ (1995) Toxicity of oxysterols to human monocyte-macrophages. Atherosclerosis 118, 67–75.CrossRefGoogle ScholarPubMed
Clifton, P (2002) Plant sterols and stanols: comparisons and contrasts. Sterols versus stanols in cholesterol-lowering: is there a difference? Atheroscler Suppl 3, 5–9.Google ScholarPubMed
Daly, GG, Finocchiaro, ET & Richardson, T (1983) Characterization of some oxidation products of β-sitosterol. J Agric Food Chem 31, 46–50.CrossRefGoogle Scholar
Dubrez, L, Savoy, I, Hamman, A & Solary, E (1996) Pivotal role of a DEVD-sensitive step in etoposide-induced and Fas-mediated apoptotic pathways. EMBO J 15, 5504–5512.CrossRefGoogle ScholarPubMed
Dutta, PC (1999) Phytosterol oxides in some samples of pure phytosterols mixture and in a few tablet supplement preparations in Finland. In Natural Antioxidant and Anticarcinogens in Nutrition, Health and Disease, pp. 316–320 [Kumpulainen, JK and Salonen, JT, editors]. Cambridge, UK: The Royal Society of Chemistry.CrossRefGoogle Scholar
Dutta, PC (2002) Determination of phytosterol oxidation products in foods and biological samples. In Cholesterol and Phytosterol Oxidation Products, Analysis, Occurrence, and Biological Effects, pp. 335–374 [Guardiola,, F, Dutta,, PC, Codony, R, Savage, GP, editors]. Champaign, IL: AOCS Press.Google Scholar
Dutta, PC & Appelqvist, LA (1997) Studies on phytosterol oxides. I: Effect of storage on the content in potato chips prepared in different vegetable oils. J Am Oil Chem Soc 74, 647–657.CrossRefGoogle Scholar
Fieser, M & Fieser, LF (1967) Reagents for Organic Synthesis, Vol. 1, pp. 136,New York, NY: J. Wiley and Sons.Google Scholar
Ghibelli, L, Coppola, S, Fanelli, C, et al. (1999) Glutathione depletion causes cytochrome c release even in the absence of cell commitment to apoptosis. FASEB J 13, 2031–2036.CrossRefGoogle ScholarPubMed
Ghibelli, L, Fanelli, C, Rotilio, G, et al. (1998) Rescue of cells from apoptosis by inhibition of active GSH extrusion. FASEB J 12, 479–486.CrossRefGoogle ScholarPubMed
Grandgirard, A (2002) Biological effects of phytosterol oxidation products, future research areas and concluding remarks. In Cholesterol and Phytosterol Oxidation Products, Analysis, Occurrence, and Biological Effects, pp. 375–382 [Guardiola,, F, Dutta,, PC, Codony, RSavage, GP, editors]. Champaign, IL: AOCS Press.Google Scholar
Grandgirard, A, Sergiel, JP, Nour, M, Demaison-Meloche, J & Ginies, C (1999) Lymphatic absorption of phytosterol oxides in rats. Lipids 34, 563–570.CrossRefGoogle ScholarPubMed
Hissin, PJ & Hilf, R (1976) A fluorometric method for determination of oxidized and reduced glutathione in tissues. Anal Biochem 74, 214–226.CrossRefGoogle ScholarPubMed
Kakis, G, Kuksis, A & Myher, JJ (1977) Injected 7-oxycholesterol and plant sterol derivatives and hepatic cholesterogenesis. Adv Exp Med Biol 82, 297–299.Google Scholar
Lake, RJ & Scholes, P (1997) Consumption of cholesterol oxides from fast foods fried in beef fat in New Zealand. J Am Oil Chem Soc 74, 1069–1075.CrossRefGoogle Scholar
Leonarduzzi, G, Sevanian, A, Sottero, B, et al. (2001) Up-regulation of the fibrogenic cytokine TGF-β 1 by oxysterols: a mechanistic link between cholesterol and atherosclerosis. FASEB J 15, 1619–1621.CrossRefGoogle Scholar
Leonarduzzi, G, Sottero, B & Poli, G (2002) Oxidised products of cholesterol: dietary and metabolic origin, and proatherosclerotic effects (review). J Nutr Biochem 13, 700–710.CrossRefGoogle Scholar
Lizard, G, Gueldry, S, Sordet, O, et al. (1998) Glutathione is implied in the control of 7-ketocholesterol-induced apoptosis, which is associated with radical oxygen species production. FASEB J 12, 1651–1663.CrossRefGoogle ScholarPubMed
Lizard, G, Monier, S, Cordelet, C, et al. (1999) Characterisation and comparison of the mode of cell death, apoptosis versus necrosis, induced by 7β-hydroxycholesterol and 7-ketocholesterol in the cells of the vascular wall. Arterioscler Thromb Vasc Biol 19, 1190–1200.CrossRefGoogle ScholarPubMed
Lyons, NM, Woods, JA & O'Brien, NM (2001) α-Tocopherol, but not γ-tocopherol inhibits 7β-hydroxycholesterol-induced apoptosis in human U937 Cells. Free Radic Res 35, 329–339.CrossRefGoogle ScholarPubMed
Moreau, RA, Whitaker, BD & Hicks, KB (2002) Phytosterols, phytostanols, and their conjugates in foods: structural diversity, quantitative analysis, and health-promoting uses. Prog Lipid Res 41, 457–500.CrossRefGoogle ScholarPubMed
Mowles, JM (1990) Mycoplasma detection. In Methods in Molecular Biology, vol. V: Animal Cell Culture, pp. 65–74 [Pollard, JW and Walker, JM, editors]. Clifton, NJ: Humana Press.Google Scholar
O'Callaghan, YC, Woods, JA & O'Brien, NM (1999) Oxysterol-induced cell death in U937 and HepG2 cells at reduced and normal serum concentrations. Eur J Nutr 38, 255–262.CrossRefGoogle ScholarPubMed
O'Callaghan, YC, Woods, JA & O'Brien, NM (2001) Comparative study of the cytotoxicity and apoptosis-inducing potential of commonly occurring oxysterols. Cell Biol Toxicol 17, 127–137.CrossRefGoogle ScholarPubMed
O'Callaghan, YC, Woods, JA & O'Brien, NM (2002) Characteristics of 7β-hydroxycholesterol-induced cell death in a human monocytic blood cell line, U937, and a human hepatoma cell line, HepG2. Toxicol In Vitro 16, 245–251.CrossRefGoogle Scholar
O'Leary, KA, Woods, JA & O'Brien, NM (2001) γ-Tocopherol is less effective than α-tocopherol in preventing oxidant-induced sister chromatid exchanges in chinese hamster V79 cells. Free Radic Res 35, 917–924.CrossRefGoogle ScholarPubMed
Olive, PL & Banath, JP (1993) Induction and rejoining of radiation-induced DNA single-strand breaks: “tail moment” as a function of position in the cell cycle. Mutat Res 294, 275–283.CrossRefGoogle ScholarPubMed
Perry, P & Wolff, S (1974) New Giemsa method for the differential staining of sister chromatids. Nature 251, 156–158.CrossRefGoogle ScholarPubMed
Plat, J, Brzezinka, H, Lutjohann, D, Mensink, RP & von Bergmann, K (2001) Oxidized plant sterols in human serum and lipid infusions as measured by combined gas-liquid chromatography-mass spectrometry. J Lipid Res 42, 2030–2038.CrossRefGoogle ScholarPubMed
Smith, PK, Krohn, RI, Hermanson, GT, et al. (1985) Measurement of protein using bicinchoninic acid. Anal Biochem 150, 76–85.CrossRefGoogle ScholarPubMed
Strauss, GHS (1991) Non-random cell killing in cryopreservation: implications for performance of the battery of leukocyte tests (BLT), I. Toxic and immunotoxic effects. Mutat Res 252, 1–15.CrossRefGoogle ScholarPubMed
Tai, CY, Chen, YC & Chen, BH (1999) Analysis, formation and inhibition of cholesterol oxidation products in foods: an overview (Part I). J Food Drug Anal 7, 243–257.Google Scholar
Therond, P, Abella, A, Laurent, D, et al. (2000) In vitro study of the cytotoxicity of isolated oxidized low-density lipoproteins fractions in human endothelial cells: Relationship with the glutathione status and cell morphology. Free Radic Biol Med 28, 585–596.CrossRefGoogle ScholarPubMed
Van de, Bovenkamp P, Kosmeijer-Schuil, TG & Katan, MB (1988) Quantification of oxysterols in Dutch foods: egg products and mixed diets. Lipids 23, 1079–1085.CrossRefGoogle Scholar
Woods, JA & O'Brien, NM (1998) Investigation of the potential genotoxicity of cholesterol oxidation products in two mammalian fibroblast cell lines. Nutr Cancer 31, 192–198.CrossRefGoogle ScholarPubMed
Woods, JA, O'Leary, KA, McCarthy, RP & O'Brien, NM (1999) Preservation of comet assay slides: comparison with fresh slides. Mutat Res 429, 181–187.CrossRefGoogle ScholarPubMed
Zieden, A, Kaminskas, A, Kristenson, M, Kucinskiene, Z, Vessby, B, Olsson, AG & Piczfalusy, U (1999) Increased plasma 7β-hydroxycholesterol concentrations in a population with a high risk for cardiovascular disease. Arterioscler Thromb Vasc Biol 19, 967–971.CrossRefGoogle Scholar