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Chen CY, Wu CH, Wu KC, Shiao LR, Chuang CM, Leung YM, Chow LWC. A basal level of γ-linolenic acid depletes Ca 2+ stores and induces endoplasmic reticulum and oxidative stresses to cause death of breast cancer BT-474 cells. CHINESE J PHYSIOL 2021; 64:202-209. [PMID: 34472451 DOI: 10.4103/cjp.cjp_30_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Gamma-linolenic acid (GLA), a natural fatty acid obtained from oils of various vegetables and seeds, has been demonstrated as an anticancer agent. In this work, we investigated the anticancer effects of GLA on breast cancer BT-474 cells. GLA at 30 μM, a concentration reportedly within the range of circulating concentrations in clinical studies, caused apoptotic cell death. GLA caused an elevation in mitochondrial Ca2+ level and a decrease in mitochondrial membrane potential. GLA treatment depleted cyclopiazonic acid (CPA)-sensitive Ca2+ store and triggered substantial Ca2+ influx. Intracellular Ca2+ release triggered by GLA was suppressed by 3 μM xestospongin C (XeC, IP3 receptor-channel blocker) and 100 μM ryanodine (ryanodine receptor-channel blocker), suggesting that the Ca2+ release was via IP3 receptor-channel and ryanodine receptor-channel. Increased expressions of p-eIF2α and CHOP were observed in GLA-treated cells, suggesting GLA-treated cells had increased expressions of p-eIF2α and CHOP, which suggest endoplasmic reticulum (ER) stress. In addition, GLA elicited increased production of reactive oxygen species. Taken together, our results suggest a basal level of GLA induced apoptotic cell death by causing Ca2+ overload, mitochondrial dysfunction, Ca2+ store depletion, ER stress, and oxidative stress. This is the first report to show that GLA caused Ca2+ store depletion and ER stress. GLA-induced Ca2+ store depletion resulted from opening of IP3 receptor-channel and ryanodine receptor-channel.
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Affiliation(s)
- Cing-Yu Chen
- Department of Physiology, China Medical University, Taichung, Taiwan
| | - Cheng-Hsun Wu
- Department of Anatomy, China Medical University, Taichung, Taiwan
| | - King-Chuen Wu
- Department of Anesthesiology, Chang Gung Memorial Hospital; Chang Gung University of Science and Technology, Chiayi, Taiwan
| | - Lian-Ru Shiao
- Department of Physiology, China Medical University, Taichung, Taiwan
| | - Chin-Min Chuang
- Department of Emergency Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Yuk-Man Leung
- Department of Physiology, China Medical University, Taichung, Taiwan
| | - Louis W C Chow
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Taipa, Macau; UNIMED Medical Institute; Organisation for Oncology and Translational Research, Hong Kong, China
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Beneficial effects of olive oil and Mediterranean diet on cancer physio-pathology and incidence. Semin Cancer Biol 2020; 73:178-195. [PMID: 33249203 DOI: 10.1016/j.semcancer.2020.11.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 12/13/2022]
Abstract
Virgin olive oil is a characteristic component and the main source of fat of the Mediterranean diet. It is a mix of high-value health compounds, including monounsaturated fatty acids (mainly oleic acid), simple phenols (such as hydroxytyrosol and tyrosol), secoiridoids (such as oleuropein, oleocanthal), flavonoids, and terpenoids (such as squalene). Olive oil consumption has been shown to improve different aspects of human health and has been associated with a lower risk of cancer. However, the underlying cellular mechanisms involved in such effects are still poorly defined, but seem to be related to a promotion of apoptosis, modulation of epigenetic patterns, blockade of cell cycle, and angiogenesis regulation. The aim of this review is to update the current associations of cancer risk with the Mediterranean diet, olive oil consumption and its main components. In addition, the identification of key olive oil components involved in anticarcinogenic mechanisms and pathways according to experimental models is also addressed.
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Yu HM, Newell M, Subedi K, Weselake RJ, Mazurak V, Field CJ. Bypassing the Δ6-desaturase enzyme and directly providing n-3 and n-6 PUFA pathway intermediates reduces the survival of two human breast cancer cell lines. EUR J LIPID SCI TECH 2015. [DOI: 10.1002/ejlt.201400464] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Howe-Ming Yu
- Division of Nutrition; University of Alberta; Edmonton Alberta Canada
| | - Marnie Newell
- Division of Nutrition; University of Alberta; Edmonton Alberta Canada
| | - Kalpana Subedi
- Division of Nutrition; University of Alberta; Edmonton Alberta Canada
| | - Randall J. Weselake
- Alberta Innovates Phytola Centre, Department of Agricultural, Food and Nutritional Sciences; University of Alberta; Edmonton Alberta Canada
| | - Vera Mazurak
- Division of Nutrition; University of Alberta; Edmonton Alberta Canada
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Polavarapu S, Mani AM, Gundala NKV, Hari AD, Bathina S, Das UN. Effect of polyunsaturated fatty acids and their metabolites on bleomycin-induced cytotoxic action on human neuroblastoma cells in vitro. PLoS One 2014; 9:e114766. [PMID: 25536345 PMCID: PMC4275295 DOI: 10.1371/journal.pone.0114766] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 11/13/2014] [Indexed: 12/20/2022] Open
Abstract
In the present study, we noted that bleomycin induced growth inhibitory action was augmented by all the polyunsaturated fatty acids (PUFAs) tested on human neuroblastoma IMR-32 (0.5 × 10(4) cells/100 µl of IMR) cells (EPA > DHA > ALA = GLA = AA > DGLA = LA: ∼ 60, 40, 30, 10-20% respectively) at the maximum doses used. Of all the prostaglandins (PGE1, PGE2, PGF2α, and PGI2) and leukotrienes (LTD4 and LTE4) tested; PGE1, PGE2 and LTD4 inhibited the growth of IMR-32 cells to a significant degree at the highest doses used. Lipoxin A4 (LXA4), 19,20-dihydroxydocosapentaenoate (19, 20 DiHDPA) and 10(S),17(S)-dihydroxy-4Z,7Z,11E,13Z,15E,19Z-docosahexaenoic acid (protectin: 10(S),17(S)DiHDoHE), metabolites of DHA, significantly inhibited the growth of IMR-32 cells. Pre-treatment with AA, GLA, DGLA and EPA and simultaneous treatment with all PUFAs used in the study augmented growth inhibitory action of bleomycin. Surprisingly, both indomethacin and nordihydroguaiaretic acid (NDGA) at 60 and 20 µg/ml respectively enhanced the growth of IMR-32 cells even in the presence of bleomycin. AA enhanced oxidant stress in IMR-32 cells as evidenced by an increase in lipid peroxides, superoxide dismutase levels and glutathione peroxidase activity. These results suggest that PUFAs suppress growth of human neuroblastoma cells, augment growth inhibitory action of bleomycin by enhancing formation of lipid peroxides and altering the status of anti-oxidants and, in all probability, increase the formation of lipoxins, resolvins and protectins from their respective precursors that possess growth inhibitory actions.
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Affiliation(s)
- Sailaja Polavarapu
- Bio-Science Research Centre, Gayatri Vidya Parishad College of Engineering Campus, Madhurawada, Visakhapatnam-530048, Andhra Pradesh, India
| | - Arul M Mani
- Bio-Science Research Centre, Gayatri Vidya Parishad College of Engineering Campus, Madhurawada, Visakhapatnam-530048, Andhra Pradesh, India
| | - Naveen K V Gundala
- Bio-Science Research Centre, Gayatri Vidya Parishad College of Engineering Campus, Madhurawada, Visakhapatnam-530048, Andhra Pradesh, India
| | - Anasuya D Hari
- Bio-Science Research Centre, Gayatri Vidya Parishad College of Engineering Campus, Madhurawada, Visakhapatnam-530048, Andhra Pradesh, India
| | - Siresha Bathina
- Bio-Science Research Centre, Gayatri Vidya Parishad College of Engineering Campus, Madhurawada, Visakhapatnam-530048, Andhra Pradesh, India
| | - Undurti N Das
- UND Life Sciences, 2020 S 360th St, # K-202, Federal Way, Washington, 98003, United States of America
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Shaikh IAA, Brown I, Wahle KWJ, Heys SD. Enhancing Cytotoxic Therapies for Breast and Prostate Cancers With Polyunsaturated Fatty Acids. Nutr Cancer 2010; 62:284-96. [DOI: 10.1080/01635580903407189] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Ho S, Calder RJ, Thomas CP, Heard CM. In-vitro transcutaneous delivery of tamoxifen and γ-linolenic acid from borage oil containing ethanol and 1,8-cineole. J Pharm Pharmacol 2010; 56:1357-64. [PMID: 15525441 DOI: 10.1211/0022357044599] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
The objective of this study was to examine the effects of ethanol and 1,8-cineole on the transcutaneous delivery of tamoxifen and γ-linolenic acid (GLA) as a two-pronged anti-breast cancer therapy. Formulations containing tamoxifen and varying concentrations of borage oil (∼25% GLA), 1,8-cineole and ethanol were prepared and the simultaneous permeation of tamoxifen and GLA determined across full-thickness pig skin using Franz-type diffusion cells over 48 h. Analysis of tamoxifen and GLA (as methyl ester) were by reverse-phase HPLC. The highest flux of tamoxifen of 488.2 ± 191 times 10−3 μg cm−2 h−1 was observed with a formulation containing 20% 1,8-cineole and 20% ethanol. The same formulation also provided the greatest flux of GLA, 830.6 times 10−3 μg cm−2 h−1. The findings from this work demonstrate the ability of 1,8-cineole and ethanol to enhance the in-vitro permeation of tamoxifen and GLA across the skin and support the plausibility of simultaneously delivering tamoxifen and GLA transcutaneously as a two-pronged anti-breast cancer system.
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Affiliation(s)
- Suzanna Ho
- Welsh School of Pharmacy, Cardiff University, CF10 3XF, UK
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Nasrollahzadeh J, Siassi F, Doosti M, Eshraghian MR, Shokri F, Modarressi MH, Mohammadi-Asl J, Abdi K, Nikmanesh A, Karimian SM. The influence of feeding linoleic, gamma-linolenic and docosahexaenoic acid rich oils on rat brain tumor fatty acids composition and fatty acid binding protein 7 mRNA expression. Lipids Health Dis 2008; 7:45. [PMID: 19014610 PMCID: PMC2605445 DOI: 10.1186/1476-511x-7-45] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2008] [Accepted: 11/16/2008] [Indexed: 11/10/2022] Open
Abstract
Background Experimental studies indicate that gamma linolenic acid (GLA) and docosahexaenoic acid (DHA) may inhibit glioma cells growth but effects of oral consumption of these fatty acids on brain tumor fatty acid composition have not been determined in vivo. Methods GLA oil (GLAO; 72% GLA), DHA oil (DHAO; 73% DHA) were fed to adult wistar rats (1 mL/rat/day) starting one week prior to C6 glioma cells implantation and continued for two weeks after implantation. Control group were fed same amount of high linoleic acid safflower oil (74–77% linoleic acid). Fatty acid composition of tumor samples was determined in a set of 8–12 animals in each group and serum fatty acid in 6 animals per each group. Gene expression of tumor fatty acid binding protein 7 (FABP7), epidermal growth factor receptor (EGFR), peroxisome proliferator activated receptor γ (PPAR-γ) and retinoid × receptor-α (RXR-α) were determined in a set of 18 animals per group. Results DHAO feeding increased EPA of brain tumors and decreased ratio of n-6/n-3 fatty acids. Serum levels of EPA were also increased in DHAO group. A similar trend in serum and tumor levels of DHA were observed in DHAO group but it did not achieve statistical significance. GLAO increased serum concentration of GLA but had no significant effect on tumor GLA or dihomo-gamma linolenic acid (DGLA) concentrations. Gene expression of FABP7 was up-regulated in tumors of DHAO group but no other significant effects were observed on EGFR, PPAR-γ or RXR-α expression, and expression of these genes in tumors of GLAO were not different from SFO group. Conclusion Dietary supplementation of DHA containing oil could be an effective way to increase levels of long chain n-3 fatty acids in brain tumors and this increase may be mediated partly by up-regulation of FABP7 expression.
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Affiliation(s)
- Javad Nasrollahzadeh
- Department of Nutrition and Biochemistry, Tehran University of Medical Sciences, Tehran, Iran.
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Shaikh IAA, Brown I, Schofield AC, Wahle KWJ, Heys SD. Docosahexaenoic acid enhances the efficacy of docetaxel in prostate cancer cells by modulation of apoptosis: the role of genes associated with the NF-kappaB pathway. Prostate 2008; 68:1635-46. [PMID: 18668525 DOI: 10.1002/pros.20830] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Evidence is growing for beneficial interactions between omega-3 fatty acids from fish and chemotherapy agents in certain human cancers. Evidence for similar effects in prostate cancer is lacking. We investigated the effects of docosahexaenoic acid (DHA-22:6n-3), a component of fish oil, on the cytotoxicity of docetaxel in prostate cancer cells. METHODS Cell viability was studied using the MTT assay and apoptosis was evaluated by flow cytometry using PI, annexin V, and JC-1 staining. Cellular signaling mechanisms that might explain the observed pro-apoptotic effects were investigated using NF-kappaB pathway specific cDNA microarrays and RT-PCR validation. RESULTS DHA enhanced the pro-apoptotic efficacy of docetaxel, synergistically, in hormone receptor positive and negative LNCaP, DU145 and PC3 cells, respectively. Cell cycle analysis showed an increase in G2M arrest and JC-1 staining showed a significant (P < 0.018) increase in apoptotic cells with combination treatments in LNCaP cells. Microarray and RTPCR showed decreased expression of FADD, AKT1, MAX, TRAF3, MAP2k4, TNFRSF11A, and RIPK1 in LNCaP cells. Similar results were obtained with DU145 cells; combinations were more effective than single treatments. Combination treatments suppressed NF-kappaB signaling that was induced by docetaxel alone; this is considered an anti-apoptotic response. CONCLUSION DHA synergistically enhanced the cytotoxic effect of docetaxel in prostate cancer cells through increased apoptosis by suppression of genes involved in the NF-kappaB pathway. This highlights the possibility of developing such combination modalities for treatment of prostate cancer.
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Affiliation(s)
- Irshad A A Shaikh
- School of Medicine and Dentistry, Cancer Medicine Research Group, University of Aberdeen, Medical School, Foresterhill, Aberdeen, UK
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Abstract
Fulvestrant (Faslodex); AstraZeneca Pharmaceuticals, Wilmington, DE) is an estrogen receptor (ER) antagonist with a novel mode of action; it binds, blocks, and increases degradation of ER. Fulvestrant (at the approved dose [250 mg/month]) is at least as effective as anastrozole (1 mg/day) in the treatment of postmenopausal women with hormone receptor-positive advanced breast cancer (HR(+) ABC) progressing or recurring on antiestrogen therapy, and is also an active first-line treatment. Although fulvestrant (250 mg/month) is clearly effective, it takes 3-6 months to achieve steady-state plasma levels. Steady-state concentrations are approximately twofold higher than those achieved with a single dose; reaching this earlier, for example, via a loading-dose (LD) regimen (250 mg/month plus 500 mg on day 0 and 250 mg on day 14 of month 1), may allow responses to be achieved more quickly and limit the possibility of early relapse. Fulvestrant high-dose (HD) regimens (500 mg/month) offer the possibility of greater antitumor activity, because (a) ER downregulation is a dose-dependent process (an approximately 70% reduction is observed with a single 250 mg dose of fulvestrant) and (b) evidence correlates greater ER downregulation with superior efficacy. A fulvestrant HD regimen offers the potential of achieving near 100% ER downregulation. There is also potential to increase fulvestrant-ER binding by reducing plasma estrogen levels, for example, with concomitant aromatase inhibitor treatment. Several ongoing trials use LD, HD, and combination regimens; results from these studies are awaited with interest. Meanwhile, fulvestrant (250 mg/month) remains a valuable additional endocrine treatment for postmenopausal women with HR(+) ABC recurring or progressing on antiestrogen therapy.
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Roberts CG, Gurisik E, Biden TJ, Sutherland RL, Butt AJ. Synergistic cytotoxicity between tamoxifen and the plant toxin persin in human breast cancer cells is dependent on Bim expression and mediated by modulation of ceramide metabolism. Mol Cancer Ther 2007; 6:2777-85. [PMID: 17913853 DOI: 10.1158/1535-7163.mct-07-0374] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Phytochemicals have provided an abundant source of novel therapeutics for the treatment of human cancers. We have previously described a novel plant toxin, persin, derived from avocado leaves, which has unique in vivo actions in the mammary epithelium and Bim-dependent, cytotoxic effects in human breast cancer cells in vitro. Compounds structurally similar to persin, such as the polyunsaturated fatty acid, conjugated linoleic acid, can attenuate steroid hormone receptor signaling and modulate the response of breast cancer cells to antiestrogens. Here, we provide evidence that persin may have similar effects by showing its potent proapoptotic synergy with the antiestrogen 4-hydroxytamoxifen. However, although persin transcriptionally down-regulates estrogen receptor (ER) expression, unlike conjugated linoleic acid, it also shows efficacy in ER-negative breast cancer cells, both alone and in combination with 4-hydroxytamoxifen, whereas normal breast epithelial cells are unaffected, suggesting it may act via a distinct, ER-independent mechanism. These proapoptotic synergistic interactions are associated with increased de novo ceramide synthesis and are dependent on expression of the proapoptotic protein Bim. These data show that persin should be further investigated as a potential novel cancer therapeutic agent because it significantly enhances the sensitivity of breast cancer cells to the cytotoxic effects of tamoxifen, regardless of their ER status, while displaying apparent specificity for the malignant phenotype.
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Affiliation(s)
- Caroline G Roberts
- Cancer Research Program, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, Australia
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11
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Lee S, Gura KM, Kim S, Arsenault DA, Bistrian BR, Puder M. Current clinical applications of omega-6 and omega-3 fatty acids. Nutr Clin Pract 2006; 21:323-41. [PMID: 16870801 DOI: 10.1177/0115426506021004323] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Recent years have brought a resurgence of research interest in fatty acids, with studied fields running the gamut of human disease. This movement has run in parallel with an increased interest in using nutrition modalities as therapeutic measures, as opposed to their conventional role as energy sources. The aim of this manuscript is to provide a basic review of current clinical applications of omega-6 and omega-3 fatty acids, with a particular focus on the latter. METHODS A selective review of the voluminous literature, including randomized controlled trials, meta-analyses, population studies, and case reports, was used to compile data and identify trends in pertinent clinical applications of fatty acid therapy. CONCLUSIONS There are a myriad of disorders and maladies that seem to benefit from fatty acid supplementation, specifically omega-3 fatty acids. It has clearly been shown that omega-3 fatty acid supplementation provides a protective benefit in heart disease, and in particular sudden cardiac death. Rheumatoid arthritis (RA) is another disease entity that has been proven to benefit from this nutrition intervention, with improvement in symptoms and diminished nonsteroidal antiinflammatory drug (NSAID) usage. In addition, many psychiatric disorders, particularly schizophrenia and major depressive disorder (MDD), have shown positive results when supplementation has been used as an adjunct to standard pharmacotherapy. The remainder of clinical applications for omega-3 fatty acids requires further investigation. Specifically, according to preliminary clinical evidence, parenteral administration of fatty acids warrants further study.
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Affiliation(s)
- Sang Lee
- Children's Hospital Boston, 300 Longwood Ave., MA 02115, USA
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Escrich E, Ramírez-Tortosa MC, Sánchez-Rovira P, Colomer R, Solanas M, Gaforio JJ. Olive Oil in Cancer Prevention and Progression. Nutr Rev 2006. [DOI: 10.1111/j.1753-4887.2006.tb00262.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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Heard CM, Gallagher SJ, Congiatu C, Harwood J, Thomas CP, McGuigan C, Nemcová M, Nouskova T. Preferential π–π complexation between tamoxifen and borage oil/γ linolenic acid: Transcutaneous delivery and NMR spectral modulation. Int J Pharm 2005; 302:47-55. [PMID: 16115741 DOI: 10.1016/j.ijpharm.2005.06.013] [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] [Received: 01/30/2005] [Revised: 06/06/2005] [Accepted: 06/10/2005] [Indexed: 11/26/2022]
Abstract
The effect of different proportions of borage oil on the in vitro transcutaneous delivery of tamoxifen were studied, with the aim of developing a gel capable of the simultaneous delivery of tamoxifen and gamma linolenic acid across (breast) skin. Supplementary work probed 1H NMR spectral data for tamoxifen in the presence of different proportions of polyunsaturated or unsaturated fatty acids. Typical, non-aqueous gels were modified to contain 1% tamoxifen and three levels of borage oil ( approximately 25% gamma linolenic acid) and the transcutaneous delivery of both tamoxifen and GLA across full thickness skin determined in vitro. Both tamoxifen and gamma linolenic acid permeated the skin with the ratio of moles being consistent at approximately 4:1. This was irrespective of time, amount of borage oil contained in the formulation (above a minimum) and the presence of other (unsaturated) excipients: mineral oil, Miglyiol 810N, white soft paraffin, PEG400 and Cabosil M5. Dose-dependent downfield shifts of tamoxifen aromatic protons were observed in the presence of borage oil and linolenic acid (gamma and alpha), but not saturated triacyl glycerol. The permeation data suggested vehicular complexation between tamoxifen and polyunsaturated constituents of borage oil and that such complexes permeated the skin intact. The 1H NMR data supported the hypothesis that such complexation was a consequence of preferential pi-pi orbital interactions between the phenyl groups of tamoxifen and the multiple double bonds of GLA. The mechanism for the permeation of intact complexes across skin remains to be elucidated.
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Affiliation(s)
- Charles M Heard
- Welsh School of Pharmacy, Cardiff University, Cardiff CF10 3XF, UK.
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Menendez JA, Colomer R, Lupu R. Inhibition of fatty acid synthase-dependent neoplastic lipogenesis as the mechanism of gamma-linolenic acid-induced toxicity to tumor cells: an extension to Nwankwo's hypothesis. Med Hypotheses 2005; 64:337-41. [PMID: 15607568 DOI: 10.1016/j.mehy.2004.06.032] [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: 06/13/2004] [Accepted: 06/24/2004] [Indexed: 10/26/2022]
Abstract
gamma-Linolenic acid (GLA), an essential omega-6 polyunsaturated fatty acid (FA) is an attractive concept as anticancer agent because it exerts selective cytotoxic on human breast cancer cells without affecting normal cells. This selective toxicity has been identified to be due, at least in part, to the production of lipid peroxides and free radicals. Interestingly, a novel hypothesis for GLA-induced tumor cell toxicity has recently been proposed. GLA, through a molecular mechanism involving the lipogenic enzyme fatty acid synthase (FAS), coordinately interrupts the pathways that replenish the pools of metabolic intermediates in the citric acid cycle (cellular anaplerosis). First, supraphysiological concentrations of GLA inhibit glycolysis, while a cytochrome P450-dependent epoxidation of GLA generates epoxides metabolites for GLA that would mimic the inhibitory action of standard FAS inhibitors such as cerulenin and C75. Second, GLA-epoxide inhibits FAS activity, thus resulting in the accumulation of cytosolic malonyl-CoA which, in turn, inhibits carnitine palmitoyl transferase I (CPT-I) and prevents FA oxidation. The recent characterization of GLA as a novel regulator of FAS expression in breast cancer cells supports and further expands this hypothesis, and directly involves FAS-dependent de novo fatty acid synthesis as the mechanism of GLA-induced toxicity to tumor cells. We hypothesize that, at low (physiological) concentrations, the inhibitory effect of GLA on FAS-regulated breast cancer cell survival is not specific and is due to cell toxicity caused by lipid peroxidation. Taking into account that the inhibitory effect of FAs on the expression of FAS in cultured hepatocytes has been shown to be related to a non-specific peroxidative mechanism, a similar GLA-dependent FAS regulatory mechanism involving peroxidative products may occur in normal and neoplastic tissues. At high (supraphysiological) concentrations of GLA, the specific downregulation of FAS gene expression leads to accumulation of the substrate for FAS, malonyl-CoA, that, as a result of FAS blockade, continue to be generated by the rate-limiting enzyme of the fatty acid biosynthetic pathway acetyl-CoA carboxilase, which is not inhibited in the absence of FAS-catalyzed long chain endogenous fatty acids. Physiologically, the elevated levels of malonyl-CoA occurring during FA biosynthesis reduce FA oxidation to prevent a futile cycle of simultaneous FA synthesis and degradation. Paradoxically, high-dose GLA treatments of FAS-overexpressing breast cancer cells will promote malonyl-CoA-induced inhibition of CPT-I and FA oxidation, thus precipitating an energy crisis that triggers decreased proliferation or apoptotic cell death. In summary, this working model presents the concept that the breast cancer adaptation in FAS expression can be exploited to develop GLA-based dietary interventions aimed at altering the FA synthesis pathway, which appears to be linked to neoplastic transformation and is associated with tumor virulence and adverse clinical outcome in a subset of human breast carcinomas.
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Affiliation(s)
- Javier A Menendez
- Department of Medicine, Evanston Northwestern Healthcare Research Institute, 1001 Unviersity Place, Evanston, IL 60201, USA.
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15
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Das UN. From bench to the clinic: gamma-linolenic acid therapy of human gliomas. Prostaglandins Leukot Essent Fatty Acids 2004; 70:539-52. [PMID: 15120717 DOI: 10.1016/j.plefa.2003.12.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2003] [Accepted: 12/11/2003] [Indexed: 11/23/2022]
Abstract
Malignant gliomas are among the most devastating of cancers and are a major cause of mortality in a young population with a median survival time of 9 months following cytoreductive surgery, radiotherapy and chemotherapy. Recent studies showed that polyunsaturated fatty acids especially gamma-linolenic acid (GLA) have selective tumoricidal action especially against malignant glioma cells both in vitro and in vivo. Limited open label clinical studies showed that intratumoral injection/infusion of GLA is safe and effective against malignant gliomas. In view of this, large-scale, double blind studies are needed to establish the usefulness of GLA in the treatment of malignant brain tumors.
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Affiliation(s)
- Undurti N Das
- UND Life Sciences, 1083 Main Street, Walpole, MA 02081, USA. [corrected]
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Karia C, Harwood JL, Morris AP, Heard CM. Simultaneous permeation of tamoxifen and γ linolenic acid across excised human skin. Further evidence of the permeation of solvated complexes. Int J Pharm 2004; 271:305-9. [PMID: 15129999 DOI: 10.1016/j.ijpharm.2003.11.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Tamoxifen is the hormonal treatment of choice in women who have hormone-dependent breast cancer and its efficacy in those women considered to have a high risk of developing breast cancer, has also been established. Gamma linolenic acid (GLA) has been shown to decrease the invasion of breast cancer and recent studies have demonstrated that GLA can enhance the oestrogen receptor down-regulation induced by tamoxifen. However, tamoxifen is associated with serious side-effects due mainly to systemic delivery, and targeted delivery of both tamoxifen and GLA would be highly beneficial. This work was a preliminary study for the development of a transcutaneous system to simultaneously deliver both tamoxifen and GLA directly to the breast. Full thickness human skin was dosed with 500 microl saturated solution of tamoxifen in borage oil (25% GLA) and the simultaneous permeation of the two actives determined. There was rapid flux with minimal lag time, the cumulative permeation at 24 h was 764.3 +/- 94.2 microg cm(-2) for GLA and 5.44 +/- 0.67 microg cm(-2) for tamoxifen: the latter being comparable to the amount of tamoxifen associated with cancerous breast tissue from a 20 mg oral dose. The ratio of GLA/tamoxifen permeated at different timepoints was quite consistent, both in terms of mass (mean 138, S.D. 15.1) and mols (mean 184, S.D. 20.3). It was determined that 2.5 molecules of GLA were associated with each molecule of tamoxifen in the permeation process, equating to a solvation cage of three molecules of triacylglycerol. This study has demonstrated the feasibility of administering simultaneously tamoxifen and GLA using borage oil as vehicle, which warrants further investigation as a novel topical two-component system in relation to or prophylaxis of those perceived at high risk of developing breast cancer. The study also provides further evidence of the permeation of solvated complexes across skin, rather than discrete penetrant molecules.
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Affiliation(s)
- Clare Karia
- Welsh School of Pharmacy, Cardiff University, Cardiff CF10 3XF, UK
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Menendez JA, Colomer R, Lupu R. ?-6 Polyunsaturated fatty acid ?-linolenic acid (18:3n-6) is a selective estrogen-response modulator in human breast cancer cells: ?-Linolenic acid antagonizes estrogen receptor-dependent transcriptional activity, transcriptionally represses estrogen receptor expression and synergistically enhances tamoxifen and ICI 182,780 (Faslodex) efficacy in human breast cancer cells. Int J Cancer 2004; 109:949-54. [PMID: 15027132 DOI: 10.1002/ijc.20096] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Clarke R, Liu MC, Bouker KB, Gu Z, Lee RY, Zhu Y, Skaar TC, Gomez B, O'Brien K, Wang Y, Hilakivi-Clarke LA. Antiestrogen resistance in breast cancer and the role of estrogen receptor signaling. Oncogene 2003; 22:7316-39. [PMID: 14576841 DOI: 10.1038/sj.onc.1206937] [Citation(s) in RCA: 347] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Antiestrogens include agents such as tamoxifen, toremifene, raloxifene, and fulvestrant. Currently, tamoxifen is the only drug approved for use in breast cancer chemoprevention, and it remains the treatment of choice for most women with hormone receptor positive, invasive breast carcinoma. While antiestrogens have been available since the early 1970s, we still do not fully understand their mechanisms of action and resistance. Essentially, two forms of antiestrogen resistance occur: de novo resistance and acquired resistance. Absence of estrogen receptor (ER) expression is the most common de novo resistance mechanism, whereas a complete loss of ER expression is not common in acquired resistance. Antiestrogen unresponsiveness appears to be the major acquired resistance phenotype, with a switch to an antiestrogen-stimulated growth being a minor phenotype. Since antiestrogens compete with estrogens for binding to ER, clinical response to antiestrogens may be affected by exogenous estrogenic exposures. Such exposures include estrogenic hormone replacement therapies and dietary and environmental exposures that directly or indirectly increase a tumor's estrogenic environment. Whether antiestrogen resistance can be conferred by a switch from predominantly ERalpha to ERbeta expression remains unanswered, but predicting response to antiestrogen therapy requires only measurement of ERalpha expression. The role of altered receptor coactivator or corepressor expression in antiestrogen resistance also is unclear, and understanding their roles may be confounded by their ubiquitous expression and functional redundancy. We have proposed a gene network approach to exploring the mechanistic aspects of antiestrogen resistance. Using transcriptome and proteome analyses, we have begun to identify candidate genes that comprise one component of a larger, putative gene network. These candidate genes include NFkappaB, interferon regulatory factor-1, nucleophosmin, and the X-box binding protein-1. The network also may involve signaling through ras and MAPK, implicating crosstalk with growth factors and cytokines. Ultimately, signaling affects the expression/function of the proliferation and/or apoptotic machineries.
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Affiliation(s)
- Robert Clarke
- Department of Oncology and Vincent T. Lombardi Cancer Center, Georgetown University School of Medicine, 3970 Reservoir Road NW, Washington, DC 20057, USA.
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