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Liu W, Degner SC, Romagnolo DF. Trans-10, cis-12 conjugated linoleic acid inhibits prolactin-induced cytosolic NADP+ -dependent isocitrate dehydrogenase expression in bovine mammary epithelial cells. J Nutr 2006; 136:2743-7. [PMID: 17056794 DOI: 10.1093/jn/136.11.2743] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Conjugated linoleic acid (CLA) has been found to exert beneficial effects on lipid profile and repress de novo fatty acid synthesis in mammary gland during lactation. However, the underlying mechanisms responsible for the antilipogenic effects of CLA have not been established. The cytosolic NADP+ -dependent isocitrate dehydrogenase (IDH1) plays a critical role in cholesterol and fatty acid biosynthesis by providing reducing equivalents as NADPH. In previous studies, we documented that the expression of IDH1 in bovine mammary epithelium was modulated by regulators of mammary differentiation and metabolic effectors. In this study, we investigated the short-term effects of prolactin (PRL) and CLA on IDH1 expression in BME-UV bovine mammary epithelial cells. In time-course experiments, we found that the treatment with PRL for 60 and 90 min elicited a significant increase in IDH1 transcript levels. Conversely, the cotreatment of BME-UV cells with PRL plus a CLA mixture for 90 min prevented the accumulation of IDH1 mRNA induced by PRL. In addition, we found that the trans-10, cis-12 CLA, but not the cis-9, trans-11 CLA isomer, inhibited basal- and PRL-induced IDH1 mRNA expression. The inhibitory effects of the trans-10, cis-12 CLA isomer on PRL-induced IDH1 expression accumulation were confirmed by quantitative real time PCR and western-blotting analysis. We propose that the inhibitory effects of CLA on milk fat synthesis in mammary epithelial cells may derive, at least in part, from repression of IDH1 expression.
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Affiliation(s)
- Wenjing Liu
- Laboratory of Mammary Gland Biology, Department of Nutritional Sciences, University of Arizona, Tucson, AZ 85721, USA
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52
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GUZEL-SEYDIM ZB, SEYDIM AC, GREENE AK, TAŞ T. Determination of antimutagenic properties of acetone extracted fermented milks and changes in their total fatty acid profiles including conjugated linoleic acids. INT J DAIRY TECHNOL 2006. [DOI: 10.1111/j.1471-0307.2006.00265.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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53
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Cho HJ, Kim EJ, Lim SS, Kim MK, Sung MK, Kim JS, Park JHY. Trans-10,cis-12, not cis-9,trans-11, conjugated linoleic acid inhibits G1-S progression in HT-29 human colon cancer cells. J Nutr 2006; 136:893-8. [PMID: 16549447 DOI: 10.1093/jn/136.4.893] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Commercial preparations of conjugated linoleic acid (CLA) contain both positional and geometric isomers of octadecadienoic acid, with cis-9,trans-11 CLA (c9t11) and trans-10,cis-12 CLA (t10c12) as the principal isomers. We showed previously that CLA reduced the incidence of colon tumors in rats treated with 1,2-dimethylhydrazine. In addition, our previous in vitro studies showed that t10c12 inhibited the growth of HT-29 and Caco-2 human colon cancer cells, whereas c9t11 had no effect on cell growth. In the present study, to examine the effects of the CLA isomers on cell cycle and cell cycle regulatory proteins, we treated HT-29 cells with various concentrations (0-4 micromol/L) of the individual CLA isomers. A DNA flow cytometric analysis revealed that t10c12 induced a G1 arrest, whereas c9t11 had no effect on the cell cycle. Western blot analysis of total cell lysates revealed no alteration in the protein expression of cyclin A, cyclin D, cyclin E, cyclin-dependent kinase (CDK) 2, or CDK4 due to t10c12 treatment. However, t10c12 substantially increased the protein expression and mRNA accumulation of the CDK inhibitor p21(CIP1/WAF1). The t10c12 isomer increased the association of p21(CIP1/WAF1) with CDK2 and proliferating cell nuclear antigen, but decreased the levels of phosphorylated retinoblastoma protein (Rb), with an increase in the levels of hypophosphorylated Rb protein. An in vitro kinase assay using histone H1 as a substrate showed that the activities of CDK2 were significantly decreased by t10c12. These results indicate that t10c12 exerts its growth inhibitory effects in colon cancer cells through the induction of G1 cell cycle arrest. The induction of p21(CIP1/WAF1) may be one of the mechanisms by which t10c12 inhibits cell cycle progression in HT-29 cells.
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Affiliation(s)
- Han Jin Cho
- Department of Food Science and Nutrition, Hallym University, Chuncheon, 200-702, Korea
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54
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Kanasaki K, Haneda M, Sugimoto T, Shibuya K, Isono M, Isshiki K, Araki SI, Uzu T, Kashiwagi A, Koya D. N-acetyl-seryl-aspartyl-lysyl-proline inhibits DNA synthesis in human mesangial cells via up-regulation of cell cycle modulators. Biochem Biophys Res Commun 2006; 342:758-65. [PMID: 16497271 DOI: 10.1016/j.bbrc.2006.02.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2006] [Accepted: 02/05/2006] [Indexed: 11/27/2022]
Abstract
N-Acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) was originally reported as a natural inhibitor of the proliferation of stem cells. To elucidate whether Ac-SDKP inhibits the proliferation of human mesangial cells, we examined the effect of Ac-SDKP on fetal calf serum (FCS)- or platelet-derived growth factor (PDGF)-BB-induced DNA synthesis and a cell proliferation. Ac-SDKP inhibited PDGF-BB- or FCS-induced DNA synthesis without cellular toxicity. The protein expression of p53 and p27kip1 was significantly increased by Ac-SDKP. Ac-SDKP also up-regulated the PDGF-BB-stimulated expression of p21cip1 and suppressed PDGF-BB-induced cyclin D1 expression. In p53 knock-out human mesangial cells made with small interference RNA, the protein expression of p21cip1 and p27kip1 was also decreased and the inhibitory effect of Ac-SDKP on mesangial proliferation was completely abolished. Ac-SDKP increased the stability of p53 protein as demonstrated by pulse-chase experiment. These results suggest that p53 is the key mediator of Ac-SDKP-induced inhibition of DNA synthesis through the up-regulation of cell cycle modulators, highlighting a potential effect of Ac-SDKP on various progressive renal diseases.
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Affiliation(s)
- Keizo Kanasaki
- Department of Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
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55
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Degner SC, Kemp MQ, Bowden GT, Romagnolo DF. Conjugated linoleic acid attenuates cyclooxygenase-2 transcriptional activity via an anti-AP-1 mechanism in MCF-7 breast cancer cells. J Nutr 2006; 136:421-7. [PMID: 16424122 DOI: 10.1093/jn/136.2.421] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Overexpression of cyclooxygenase-2 (COX-2) is regarded as a causative factor in the onset of tumorigenesis of the breast. In this study, we investigated the effects of conjugated linoleic acid (CLA) on COX-2 transcription in MCF-7 breast cancer cells. Results of transient transfection studies revealed that treatment with a CLA mix or selected isomers (c9, t11-CLA; t10, c12-CLA) at concentrations ranging from 20 to 80 micromol/L, attenuated COX-2 transcription induced by the proinflammatory agent 12-O-tetradecanoylphorbol-13-acetate (TPA). In addition, the CLA mix inhibited TPA-induced activity of the collagenase-1 promoter. Using electrophoretic mobility shift assays, we found that the CLA mix reduced TPA-induced recruitment of nuclear proteins to a cAMP response element (CRE) in the COX-2 promoter and a consensus TPA-responsive element (TRE) in the collagenase-1 promoter. Both CRE and TRE are binding sites for activator protein-1 (AP-1). Binding studies revealed that the t10, c12-CLA isomer was more effective than the CLA mix or c9, t11-CLA in reducing binding of cJun to either the COX-2 CRE or collagenase-1 TRE, whereas linoleic acid increased binding to both elements. Overexpression of the AP-1 member, c-Jun, reversed the inhibitory effects of the CLA mix on COX-2 transcription, and restored binding of nuclear proteins to the CRE and TRE. Collectively, these results suggest that CLA represses AP-1-mediated activation of COX-2 transcription.
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Affiliation(s)
- Stephanie C Degner
- Department of Nutritional Sciences, Arizona Cancer Center, The University of Arizona, Tucson, AZ 85721, USA
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56
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Hubbard NE, Lim D, Erickson KL. Beef tallow increases the potency of conjugated linoleic acid in the reduction of mouse mammary tumor metastasis. J Nutr 2006; 136:88-93. [PMID: 16365064 DOI: 10.1093/jn/136.1.88] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Animal studies consistently show that dietary conjugated linoleic acid (CLA) reduces mammary tumorigenesis including metastasis. Relatively low concentrations of CLA are required for those effects, and a threshold level exists above which there is no added reduction. We reasoned that the concentration of CLA required to effectively alter mammary tumor metastasis may be dependent on the type of dietary fat because select fatty acids can enhance or suppress normal or malignant cell growth and metastasis. For this study, the diets (a total of 12 different groups) differed in fatty acid composition but not in energy from fat (40%). In experiments involving spontaneous metastasis, mice were fed for 11 wk; in experiments in which mice were injected i.v. with tumor cells, they were fed for 7 wk. Mice were then assessed for the effect of CLA concentration on mammary tumorigenesis. Mammary tumor growth was not altered, but metastasis was significantly decreased when beef tallow (BT) replaced half of a defined vegetable fat blend (VFB). That blend reflects the typical fat content of a Western diet. In addition, that same VFB:BT diet lowered the concentration of CLA required to significantly decrease mammary tumor metastasis from 0.1% of the diet to 0.05%. A diet in which corn oil replaced half of the VFB did not lower the threshold from 0.1 to 0.05%. In vitro, the main fatty acid in vegetable oil, linoleic acid, reduced the efficacy of CLA toxicity on mammary tumor cells in culture. Alternatively, fatty acids normally found in BT, such as oleic, stearic, and palmitic acids, either did not change or enhanced the cytolytic effects of CLA isomers on mouse mammary tumor cells in culture. These data provide evidence that dietary BT, itself with negligible levels of CLA, may increase the efficacy of dietary CLA in reducing mammary tumorigenesis.
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Affiliation(s)
- Neil E Hubbard
- Department of Cell Biology and Human Anatomy, University of California, School of Medicine, Davis, CA, USA.
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57
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Lee SH, Yamaguchi K, Kim JS, Eling TE, Safe S, Park Y, Baek SJ. Conjugated linoleic acid stimulates an anti-tumorigenic protein NAG-1 in an isomer specific manner. Carcinogenesis 2005; 27:972-81. [PMID: 16286461 DOI: 10.1093/carcin/bgi268] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Conjugated linoleic acids (CLAs), naturally occurring fatty acids in ruminant food products, have anti-tumorigenic and pro-apoptotic properties in animal as well as in vitro models of cancer. However, the cellular mechanism has not been fully understood. NAG-1 (non-steroidal anti-inflammatory drug-activated gene-1) is induced by several dietary compounds and belongs to a TGF-beta superfamily gene associated with pro-apoptotic and anti-tumorigenic activities. The present study was performed to elucidate the molecular mechanism by which CLA stimulates anti-tumorigenic activity in human colorectal cancer (CRC) cells. The trans-10, cis-12-CLA (t10,c12-CLA) repressed cell proliferation and induced apoptosis, whereas linoleic acid or c9,t11-CLA showed no effect on cell proliferation and apoptosis. We also found that t10,c12-CLA induced the expression of a pro-apoptotic gene, NAG-1, in human CRC cells. Inhibition of NAG-1 expression by small interference RNA (siRNA) results in repression of t10,c12-CLA-induced apoptosis. Microarray analysis using t10,c12-CLA-treated HCT-116 cells revealed that activating transcription factor 3 (ATF3) was induced and its expression was confirmed by western analysis. The t10,c12-CLA treatment followed by the overexpression of ATF3 increased NAG-1 promoter activity in HCT-116 cells. We further provide the evidence that t10,c12-CLA inhibited the phosphorylation of AKT and the blockage of GSK-3 by siRNA abolished t10,c12-CLA-induced ATF3 and NAG-1 expression. The current study demonstrates that t10,c12-CLA stimulates ATF3/NAG-1 expression and subsequently induces apoptosis in an isomer specific manner. These effects may be through inhibition of AKT/GSK-3beta pathway in human CRC cells.
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Affiliation(s)
- Seong-Ho Lee
- Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA
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58
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Lim DY, Tyner AL, Park JB, Lee JY, Choi YH, Park JHY. Inhibition of colon cancer cell proliferation by the dietary compound conjugated linoleic acid is mediated by the CDK inhibitor p21CIP1/WAF1. J Cell Physiol 2005; 205:107-13. [PMID: 15880444 DOI: 10.1002/jcp.20380] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Our previous studies indicated that dietary conjugated linoleic acid (CLA) inhibits colon tumor cell proliferation in vitro and in vivo. To identify mechanisms by which CLA regulates growth arrest, the HT-29 human colon carcinoma cell line was treated with various physiological concentrations of CLA and analyzed by flow cytometry. We detected a dose-dependent increase in the percentage of cells arrested in G1 after CLA treatment that was accompanied by induction of the cyclin dependent kinase (CDK) inhibitor p21CIP1/WAF. CLA addition also led to increased p21 expression in HCT116 and SW480 cells, indicating that p21 induction is a general consequence of CLA treatment in colon cancer cells. Since both HT-29 and SW480 cells have mutant p53, our data indicate that p53 is not essential for induction of p21. In addition to an increase in p21 levels, HT-29 cell growth arrest was also accompanied by moderate decreases in Cyclin A, D1, E, and proliferating cell nuclear antigen (PCNA) levels. Following CLA treatment, p21 associated with and inhibited CDK4 and CDK2, and this correlated with reduced phosphorylation of retinoblastoma proteins. Increased association of p21 with PCNA was also detected. Dietary CLA inhibits cell cycle progression by inducing p21, which negatively regulates the growth promoting activities of CDK/cyclins and PCNA. These studies indicate that physiological concentrations of CLA inhibit growth of colon cancer cells with either wild-type or mutant p53, and may have therapeutic benefits in vivo.
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Affiliation(s)
- Do Y Lim
- Division of Life Sciences, Hallym University, Chunchon, Korea
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59
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Ohtsu H, Ho E, Huang YS, Chuang LT, Bray TM. Congulated linoleic acid decreases cellular proliferation and inhibits nuclear factor–κB and activator protein 1 activation in PC3 cancerous prostate epithelial cells. Nutr Res 2005. [DOI: 10.1016/j.nutres.2005.05.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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60
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Lampen A, Leifheit M, Voss J, Nau H. Molecular and cellular effects of cis-9, trans-11-conjugated linoleic acid in enterocytes: Effects on proliferation, differentiation, and gene expression. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1735:30-40. [PMID: 15935729 DOI: 10.1016/j.bbalip.2005.01.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Revised: 01/20/2005] [Accepted: 01/24/2005] [Indexed: 11/15/2022]
Abstract
It has been hypothesized that dietary conjugated linoleic acids (CLA) may inhibit colon tumorigenesis. The aim of our study was to investigate the cellular and molecular effects of cis-9 (9Z), trans-11 (11E)-CLA on the proliferation, differentiation, interaction with peroxisome proliferator-activated receptors (PPARs), and expression of genes relevant in the APC-beta-catenin-TCF4 signalling pathway in human HT-29 and Caco-2 colon cells. We found that 9Z,11E-CLA inhibited the proliferation of HT-29 and Caco-2 cells. Trans-vaccenic acid (VA) showed no antiproliferative effects at all. We determined that 9Z,11E-CLA induced cell differentiation as measured by intestinal alkaline phosphatase (IAP) enzyme activity in Caco-2 cells, mRNA expression of IAP, and activation of a 5' flanking region of IAP. The 9Z,11E-CLA activated human PPARdelta as measured in a reporter gene assay. Treatment of HT29 cells in the poliferation phase with 9Z,11E-CLA repressed mRNA-expression of proliferation genes such as c-myc, cyclin D1 and c-jun in a concentration dependent manner. The promoter activities of c-myc and AP1 were also inhibited after incubation with 9Z,11E-CLA. beta-Catenin mRNA and protein expression was also repressed by the treatment with 9Z,11E-CLA. In addition, the mRNA expression of PPARdelta was repressed by treatment of the HT-29 cells with 9Z,11E-CLA. We conclude that 9Z,11E-CLA has an antiproliferative effect at the cellular and molecular levels in human colon cells. The results indicate that the preventive effects of CLA in the development of colon cancer may be due to their downregulation of some target genes of the APC-beta-catenin-TCF-4- and PPARdelta signalling pathway.
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Affiliation(s)
- A Lampen
- Institut für Lebensmitteltoxikologie, Stiftung Tierärztliche Hochschule Hannover, Germany.
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61
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Graves E, Hitt A, Pariza MW, Cook ME, McCarthy DO. Conjugated linoleic acid preserves gastrocnemius muscle mass in mice bearing the colon-26 adenocarcinoma. Res Nurs Health 2005; 28:48-55. [PMID: 15625711 DOI: 10.1002/nur.20052] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cancer cachexia is a syndrome of weight loss, muscle wasting, fatigue, and anorexia that occurs in patients with advanced or recurrent solid tumor disease. Tumor necrosis factor-alpha (TNFalpha) and prostaglandin E2 (PGE2) have been implicated in the biology of cachexia and serve as possible targets for treatment of this condition. Conjugated linoleic acid (CLA) is a polyunsaturated fatty acid that alters the synthesis of PGE2 and reduces the negative effects of TNF on body weight of healthy mice. We hypothesized that a diet supplemented with .5% CLA might reduce muscle wasting in mice bearing the colon-26 adenocarcinoma, an animal model of cancer cachexia. CLA preserved gastrocnemius muscle mass and reduced TNF receptors in muscle of tumor-bearing mice. These data suggest that CLA may preserve muscle mass by reducing the catabolic effects of TNF on skeletal muscle.
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Affiliation(s)
- Erin Graves
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
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62
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Kim JH, Hubbard NE, Ziboh V, Erickson KL. Conjugated linoleic acid reduction of murine mammary tumor cell growth through 5-hydroxyeicosatetraenoic acid. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1687:103-9. [PMID: 15708358 DOI: 10.1016/j.bbalip.2004.11.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Revised: 11/09/2004] [Accepted: 11/09/2004] [Indexed: 12/18/2022]
Abstract
Conjugated linoleic acid (CLA) is a dietary fatty acid that has been shown to reduce tumorigenesis and metastasis in breast, prostate and colon cancer in animals. However, the mechanism of its action has not been clarified. The goal of this study was to determine whether CLA altered mouse mammary tumor cell growth and whether specific metabolites of the lipoxygenase pathway were involved in CLA action. Both t10, c12-CLA and a lipoxygenase inhibitor, but not c9, t11-CLA or linoleic acid (LA), reduced mouse mammary tumor cell viability and growth by inducing apoptosis and reducing cell proliferation. t10, c12-CLA reduced the production of the 5-lipoxygenase metabolite, 5-hydroxyeicosatetraenoic acid (5-HETE). That effect was not seen with c9, t11-CLA or LA. Adding 5-HETE back to tumor cells reduced the t10, c12-CLA effect on both apoptosis and cell proliferation. These data suggest that t10, c12-CLA reduction of tumor cell growth may involve the suppression of the 5-lipoxygenase metabolite, 5-HETE, with subsequent effects on apoptosis and cell proliferation.
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Affiliation(s)
- Jung-Hyun Kim
- Department of Cell Biology and Human Anatomy, University of California, School of Medicine, One Shields Avenue, Davis, CA 95616-8641, USA
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63
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Colitti M, Stradaioli G, Stefanon B. Mammary cell turnover in lactating ewes is modulated by changes of energy fuels. Res Vet Sci 2005; 78:53-9. [PMID: 15500840 DOI: 10.1016/j.rvsc.2004.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2004] [Indexed: 11/28/2022]
Abstract
The study of cell turnover of mammary gland helps to gain understanding of the subtle modulation that largely determines milk production. To evaluate the effect of diet composition on cell turnover of mammary gland, pluriparous sheep were allotted to three experimental groups and fed from day 33 after lambing a control diet (BD), a high starch (HS) diet or a high fat (HF) diet. Biopsies of mammary gland tissue were collected at 50 days after lambing for in situ detection of cell death and RT-PCR analysis of bax, bcl-2, caspase-3 and GST expressions. Both apoptotic and proliferation indexes were significantly higher (P<0.05) in the BD group compared to HS and HF groups. The relative expressions of GST were significantly greater (P<0.05) in HF group compared to the BD and HS groups. There was a significant increase in the ratio of bcl-2 to bax mRNA in the HS and HF groups. Availability of energy substrates for mammary gland can interfere with the cell fate, modulating genes involved in the control of oxidative stress which, in turn, can indirectly regulate cell apoptosis and proliferation.
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Affiliation(s)
- M Colitti
- Dipartimento di Scienze della Produzione Animale, Facoltà di Medicina Veterinaria, Università di Udine, Via delle Scienze, 208, 33100 Udine, Italy
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64
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Abstract
In recent years, numerous studies have been published on the health effects of yogurt and the bacterial cultures used in the production of yogurt. In the United States, these lactic acid-producing bacteria (LAB) include Lactobacillus and Streptococcus species. The benefits of yogurt and LAB on gastrointestinal health have been investigated in animal models and, occasionally, in human subjects. Some studies using yogurt, individual LAB species, or both showed promising health benefits for certain gastrointestinal conditions, including lactose intolerance, constipation, diarrheal diseases, colon cancer, inflammatory bowel disease, Helicobacter pylori infection, and allergies. Patients with any of these conditions could possibly benefit from the consumption of yogurt. The benefits of yogurt consumption to gastrointestinal function are most likely due to effects mediated through the gut microflora, bowel transit, and enhancement of gastrointestinal innate and adaptive immune responses. Although substantial evidence currently exists to support a beneficial effect of yogurt consumption on gastrointestinal health, there is inconsistency in reported results, which may be due to differences in the strains of LAB used, in routes of administration, or in investigational procedures or to the lack of objective definition of "gut health." Further well-designed, controlled human studies of adequate duration are needed to confirm or extend these findings.
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Affiliation(s)
- Oskar Adolfsson
- Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington Street, Boston, MA 02111, USA
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65
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Abstract
The amount of scientific literature on conjugated linoleic acid (CLA) is growing at a phenomenal rate. Animal studies and clinical trials indicate the possibility that CLA could be useful in improving human health in a number of areas, eg, controlling body fat gain and enhancing immunity while also reducing inflammation and other adverse effects typically associated with immune enhancement. The background of this growing research field and mechanistic insights from animal and cell culture experiments are briefly reviewed. Experimental and clinical data relating to the safety and effectiveness of CLA in humans are presented and discussed.
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Affiliation(s)
- Michael W Pariza
- Food Research Institute, Department of Food Microbiology and Toxicology, University of Wisconsin-Madison 53706, USA.
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