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Kaur J, Sanyal SN. Alterations in membrane fluidity and dynamics in experimental colon cancer and its chemoprevention by diclofenac. Mol Cell Biochem 2010; 341:99-108. [PMID: 20336351 DOI: 10.1007/s11010-010-0441-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2009] [Accepted: 03/11/2010] [Indexed: 11/26/2022]
Abstract
We examined the role of membrane fluidity and dynamics as important early events in the carcinogenic transformation of colonic epithelial cells. 1,2-Dimethylhydrazine dihydrochloride (DMH) was used to induce initial stages of colon cancer and diclofenac was used for chemoprevention. To determine alterations of membrane fluidity of rat colonic epithelial cells, fluidity (inverse of fluorescence polarization) and order parameter were studied with 1,6-diphenylhexatriene (DPH) polarization. Order parameter as well as fluorescence polarization was found to be significantly decreased, thus demonstrating an increase in the fluidity of the membrane. To further confirm the fluidity changes, microviscosity of the cell membrane was studied using pyrene excimer formation, which showed a significant decrease in microviscosity and hence elevated membrane fluidity (translational diffusion). The colonocytes were stained with merocyanine 540 (MC540) to further elaborate the changes in membrane fluidity and lipid packing. The increased number of colonocytes showing high MC540 fluorescence pointed towards the wide spaces and hence, high fluidity in the membrane after DMH treatment. Membrane dynamics studies, i.e., lipid phase separation and membrane phase state were carried out using N-NBD-PE and Laurdan, respectively. We saw a transition from the gel to a more liquid crystalline state of the membrane in the Laurdan experiment. Further more percentage quenching (%Q) value of N-NBD-PE showed less phase separation (or domain formation). Diclofenac co-administration with DMH was successful in reverting the changes observed, confirming the role of these anti-inflammatory drugs in considerable lipid affinity and consequently in the chemoprevention of early stages of colon cancer.
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Affiliation(s)
- Jasmeet Kaur
- Department of Biophysics, Panjab University, Chandigarh 160 014, India
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Ji S, Hardy RW, Wood PA. Transgenic expression of n-3 fatty acid desaturase (fat-1) in C57/BL6 mice: Effects on glucose homeostasis and body weight. J Cell Biochem 2009; 107:809-17. [PMID: 19396841 DOI: 10.1002/jcb.22179] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The fat-1 gene, derived from Caenorhabditis elegans, encodes for a fatty acid n-3 desaturase. In order to study the potential metabolic benefits of n-3 fatty acids, independent of dietary fatty acids, we developed seven lines of fat-1 transgenic mice (C57/BL6) controlled by the regulatory sequences of the adipocyte protein-2 (aP2) gene for adipocyte-specific expression (AP-lines). We were unable to obtain homozygous fat-1 transgenic offspring from the two highest expressing lines, suggesting that excessive expression of this enzyme may be lethal during gestation. Serum fatty acid analysis of fat-1 transgenic mice (AP-3) fed a high n-6 unsaturated fat (HUSF) diet had an n-6/n-3 fatty acid ratio reduced by 23% (P < 0.025) and the n-3 fatty acid eicosapentaenoic acid (EPA) concentration increased by 61% (P < 0.020). Docosahexaenoic acid (DHA) was increased by 19% (P < 0.015) in white adipose tissue. Male AP-3-fat-1 line of mice had improved glucose tolerance and reduced body weight with no change in insulin sensitivity when challenged with a high-carbohydrate (HC) diet. In contrast, the female AP-3 mice had reduced glucose tolerance and no change in insulin sensitivity or body weight. These findings indicate that male transgenic fat-1 mice have improved glucose tolerance likely due to increased insulin secretion while female fat-1 mice have reduced glucose tolerance compared to wild-type mice. Finally the inability of fat-1 transgenic mice to generate homozygous offspring suggests that prolonged exposure to increased concentrations of n-3 fatty acids may be detrimental to reproduction.
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Affiliation(s)
- Shaonin Ji
- Department of Genetics, University of Alabama at Birmingham, 35294, USA
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Salem ML. Systemic treatment with n-6 polyunsaturated fatty acids attenuates EL4 thymoma growth and metastasis through enhancing specific and non-specific anti-tumor cytolytic activities and production of TH1 cytokines. Int Immunopharmacol 2005; 5:947-60. [PMID: 15829411 DOI: 10.1016/j.intimp.2004.12.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2004] [Revised: 12/27/2004] [Accepted: 12/27/2004] [Indexed: 02/07/2023]
Abstract
Recently, there has been a great interest in the effects of different types of n-6 polyunsaturated acids (n-6 PUFAs) upon the immune system and cancer development. However, the effects of n-6 PUFAs are still controversial and as yet undefined. The present study aimed to investigate the anti-tumor effects of n-6 PUFAs against EL4 thymoma and the associated immune mechanisms. To this, sesame oil, a vegetable oil enriched with n-6 PUFAs, or free linoleic acid (LA) were administered intraperitoneally into C57BL/6 mice before and after challenge with EL4 lymphoma cells. Treatment with either sesame oil or LA attenuated the growth and metastasis of EL4 lymphoma. The anti-tumor effect of LA was superior to that of sesame oil, and associated with an increase in the survival rate of the tumor-bearing mice. In addition, both sesame oil and LA showed dose-dependent anti-lymphoma growth in vitro. Treatment with LA generated significant increases in the anti-lymphoma cytolytic and cytostatic activities of T cells and macrophages, respectively, and enhanced production of IL-2 and IFN-gamma while decreased production of IL-4, IL-6 and IL-10. In summation, the results suggest that n-6 PUFAs, represented by LA, can attenuate EL4 lymphoma growth and metastasis through enhancing the specific and non-specific anti-tumor cytolytic activities and production of TH1 cytokines. These findings might be of great importance for a proper design of systemic nourishment with PUFAs emulsions for cancer patients.
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Affiliation(s)
- Mohamed Labib Salem
- Department of Surgery, Section of Surgical Oncology, Holling Cancer Center R313, Medical University of South Carolina, Charleston, SC 29425, USA.
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Effects of nutritional lipids on diabetic manifestations and Δ6 desaturase mRNA level in streptozotocin treated mice. Nutr Res 2004. [DOI: 10.1016/j.nutres.2003.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Nathoo N, Barnett GH, Golubic M. The eicosanoid cascade: possible role in gliomas and meningiomas. J Clin Pathol 2004; 57:6-13. [PMID: 14693827 PMCID: PMC1770171 DOI: 10.1136/jcp.57.1.6] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Eicosanoids constitute a large family of biologically active lipid mediators that are produced by two enzyme classes, cyclooxygenases (COX-1 and COX-2) and lipoxygenases (5-LO, 12-LO, and 15-LO). Increasing evidence suggests that in addition to a variety of epithelial malignancies, the two most common types of human brain tumour, gliomas and meningiomas, aberrantly overexpress eicosanoid producing enzymes and release a spectrum of eicosanoids that may promote tumorigenesis and the development of peritumorous brain oedema. Glioma and meningioma cells are killed in vitro and in animal models when exposed to COX-2 and 5-LO inhibitors, and their effectiveness is under investigation in clinical trials for treatment of patients with malignant brain tumours. However, despite research into the role of the eicosanoid cascade in the tumorigenesis of human brain tumours, many important questions remain unanswered. Current and newer agents that specifically target key players of the eicosanoid cascade could change the approach to treating brain tumours, because their benefits may lie in their synergism with conventional cytotoxic treatments and/or with other novel agents targeted against other procarcinogenic pathways.
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Affiliation(s)
- N Nathoo
- Brain Tumour Institute and Department of Neurosurgery, Cleveland Clinic Foundation, Cleveland, 44195 Ohio, USA.
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Macronutrients. Dis Mon 2004. [DOI: 10.1016/j.disamonth.2004.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abayasekara DR, Wathes DC. Effects of altering dietary fatty acid composition on prostaglandin synthesis and fertility. Prostaglandins Leukot Essent Fatty Acids 1999; 61:275-87. [PMID: 10670689 DOI: 10.1054/plef.1999.0101] [Citation(s) in RCA: 147] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Several studies over the past 20 years have demonstrated that subjects on diets composed of substances with high levels of n-3 polyunsaturated fatty acids (PUFAs) (e.g. fish) have a decreased incidence of heart disease. On this basis, a recent report from the Department of Health has advised UK consumers to decrease the proportion of saturated as opposed to unsaturated fats in their diet and to increase the ratio of n-3 to n-6 PUFAs. This could be achieved by altering the amounts of these constituents in milk and meat. n-3 Fatty acids can most easily be added to animal feed as either fish oil or linseed oil and can be increased in the blood and milk of ruminants following protection to avoid hydrogenation in the rumen. In western countries the ratio of consumption of n-6 to n-3 PUFAs is greater than 10 and current evidence tends to suggest that a ratio nearer 5 would be more desirable and compatible with cardiovascular well being. As fertility in the UK dairy herd is already poor, it is important to establish whether alterations in dietary n-3 and n-6 PUFAs affects herd fertility before widespread changes in animal diets are recommended. Therefore, this review considers the role played by PUFAs and eicosanoids in fertility, with particular reference to the implications for farm livestock production. The evidence reviewed shows that alteration of the concentration and ratio of n-6 and n-3 PUFAs in feeds can influence prostaglandin synthesis/metabolism in a number of mammalian systems. The changed patterns of prostaglandin synthesis can as a consequence, affect the diverse functions (e.g. hormone secretion) that are normally mediated via prostaglandins. Similarly, changes in prostaglandin synthesis effected through manipulation of PUFAs has a major bearing on fertility (as PGs affect many reproductive parameters, e.g. ovulation). Several studies in cattle and other mammals, show that feeding or infusing different types of fat with varying PUFA content to females can alter: the number and size of ovarian follicles, the ovulation rate, progesterone production by the corpus luteum, the timing of luteolysis and gestational length. In the male most recent work has focussed on sperm production and experiments in fowl have demonstrated clear effects of dietary PUFAs on both the sperm membrane phospholipid composition and on fertilizing ability.
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Affiliation(s)
- D R Abayasekara
- Reproduction and Development Group, Department of Veterinary Basic Sciences, Royal Veterinary College, London, UK.
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Aki T, Shimada Y, Inagaki K, Higashimoto H, Kawamoto S, Shigeta S, Ono K, Suzuki O. Molecular cloning and functional characterization of rat delta-6 fatty acid desaturase. Biochem Biophys Res Commun 1999; 255:575-9. [PMID: 10049752 DOI: 10.1006/bbrc.1999.0235] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mammalian cDNA fragments putatively encoding amino acid sequences characteristic of the fatty acid desaturase were obtained using expressed sequence tag (EST) sequence informations. These fragments were subsequently used to screen a rat liver cDNA library, yielding a 1573-bp clone. Expression of DNA fragment containing either of two possible open reading frames (nucleotide numbers 97-1431 and 148-1431) of the isolated clone in yeast led to the accumulation of gamma-linolenic acid in the presence of exogenous linoleic acid. In this system, the addition of alpha-linolenic acid also resulted in the accumulation of its Delta-6 desaturated product whereas dihomo-gamma-linolenic acid failed to be a substrate. These results indicate that the protein encoded by the rat cDNA is Delta-6 fatty acid desaturase, and the first 17 amino acids corresponding to the coding region 97-147 of the clone are not required to function in yeast.
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Affiliation(s)
- T Aki
- Department of Molecular Biotechnology, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, 739-8527, Japan.
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Taber L, Chiu CH, Whelan J. Assessment of the arachidonic acid content in foods commonly consumed in the American diet. Lipids 1998; 33:1151-7. [PMID: 9930399 DOI: 10.1007/s11745-998-0317-4] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Arachidonic acid (AA) is an extremely important fatty acid involved in cell regulation. When provided in the diet, it is cogently incorporated in membrane phospholipids and enhances eicosanoid biosynthesis in vivo and in vitro; however, controversy exists as to the levels of AA in food and in the diet. This study determined the amount of AA in cooked and raw portions of beef (rib eye), chicken (breast and thigh), eggs, pork (loin), turkey (breast), and tuna; it compared these results to values published in Agriculture Handbook No. 8 (HB-8). The cooked portions were prepared as described in HB-8. With the exception of chicken thigh and tuna, the levels of AA (w/w) in the selected foods analyzed were significantly higher, in general, than those values published in HB-8. The greatest differences were observed in beef (raw and cooked), turkey breast (raw and cooked), and pork (cooked) where AA levels were twice that of the values in HB-8. In contrast, the AA and n-3 fatty acid contents in tuna were almost half the HB-8 values. The present data indicate that HB-8 tends to underreport the amounts of AA in a number of foods commonly consumed in the American diet, and new initiatives should be considered to validate and update the current database for fatty acid composition of foods.
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Affiliation(s)
- L Taber
- Department of Nutrition, University of Tennessee, Knoxville 37996-1900, USA
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Streekstra H. On the safety of Mortierella alpina for the production of food ingredients, such as arachidonic acid. J Biotechnol 1997; 56:153-65. [PMID: 9304876 DOI: 10.1016/s0168-1656(97)00109-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mortierella alpina is the most efficient production organism for arachidonic acid (AA) presently known. Since AA is being developed as a food ingredient, and since M. alpina has no history of use for such applications, we have undertaken this safety evaluation. M. alpina is a common soil fungus, to which humans are frequently exposed. The production strains are non-pathogenic and do not form potentially allergenic spores under production conditions. Moreover, there are no reliable reports in the literature connecting the species with disease or allergenic responses. No production of mycotoxins was observed, in line with the absence of literature reports describing such products, and with the results of toxicological tests. On solid growth media the strains showed antibiotic activity against Gram-positive bacteria. In submerged culture, which is used for AA production, no significant antibiotic activity was found. We conclude that M. alpina in general, and the AA production strains CBS 168.95 and CBS 169.95 in particular, should be considered safe for the submerged production of food ingredients.
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Affiliation(s)
- H Streekstra
- Gist-brocades B.V. Corporate New Business Development, Delft, Netherlands
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