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Tokudome S, Kuriki K, Yokoyama Y, Sasaki M, Joh T, Kamiya T, Cheng J, Ogawa K, Shirai T, Imaeda N, Goto C, Tokudome Y, Ichikawa H, Okuyama H. Dietary n-3/long-chain n-3 polyunsaturated fatty acids for prevention of sporadic colorectal tumors: a randomized controlled trial in polypectomized participants. Prostaglandins Leukot Essent Fatty Acids 2015; 94:1-11. [PMID: 25451556 DOI: 10.1016/j.plefa.2014.09.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 08/06/2014] [Accepted: 09/07/2014] [Indexed: 12/31/2022]
Abstract
To address preventive effects of n-3 PUFAs/LC n-3 PUFAs on CRTs, a randomized controlled trial was conducted. One-hundred four experimental group participants were advised to increase intake of n-3 PUFAs, including fish/shell fish, fish oil supplements and perilla oils, and to decrease consumption of n-6 PUFAs and fats/oils as a whole for 24 months. One-hundred one control group participants were only cautioned to reduce consumption of fats/oils as a whole. Random allocation was satisfactorily attained, and participants sufficiently complied with our regimen. Intakes, plasma concentrations, and compositions of the RBC and sigmoid colon membranes of n-3 PUFAs, LC n-3 PUFAs, EPA and DHA increased, and the ratios of n-6 PUFAs/n-3 PUFAs and AA/LC n-3 PUFAs decreased without any adverse response. Twenty-four months after the intervention, the multivariate-adjusted hazard ratio (95% confidence intervals) was estimated to be 0.805 (0.536-1.209) with a signal towards the reduced CRT incidence.
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Affiliation(s)
- Shinkan Tokudome
- Department of Public Health, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan; National Institute of Health and Nutrition, Shinjuku-ku, Tokyo, Japan; Social Welfare Institutions Seizanri-kai, Biwajima Care Center, Nishi-ku, Nagoya, Japan.
| | - Kiyonori Kuriki
- Department of Public Health, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan; Department of Nutrition and Health Sciences, University of Shizuoka, Suruga-ku, Shizuoka, Japan
| | - Yoshifumi Yokoyama
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan; Nagoya Medical Association Health Care Center, Higashi-ku, Nagoya, Japan
| | - Makoto Sasaki
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan; Department of Gastroenterology, Aichi Medical University, Nagakute, Japan
| | - Takashi Joh
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan
| | - Takeshi Kamiya
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan
| | - Jinglei Cheng
- Department of Public Health, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan
| | - Kumiko Ogawa
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan; Division of Pathology, National Institute of Health Sciences, Setagaya-ku, Tokyo, Japan
| | - Tomoyuki Shirai
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan; Nagoya City Rehabilitation Center, Mizuho-ku, Nagoya, Japan
| | - Nahomi Imaeda
- Department of Public Health, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan; Department of Food Science and Nutrition, Nagoya Women's University, Mizuho-ku, Nagoya, Japan
| | - Chiho Goto
- Department of Public Health, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan; Department of Health and Nutrition, Nagoya Bunri University, Inazawa, Japan
| | - Yuko Tokudome
- Department of Public Health, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan; School of Nutritional Sciences, Nagoya University of Arts and Sciences, Nisshin, Japan
| | - Hiromitsu Ichikawa
- Department of Public Health, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Japan
| | - Harumi Okuyama
- Institute for Consumer Science and Human Life, Kinjo Gakuin University, Moriyama-ku, Nagoya, Japan
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Galano A, Francisco Marquez M, Pérez-González A. Ellagic acid: an unusually versatile protector against oxidative stress. Chem Res Toxicol 2014; 27:904-18. [PMID: 24697747 DOI: 10.1021/tx500065y] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Several aspects related to the antioxidant activity of ellagic acid were investigated using the density functional theory. It was found that this compound is unusually versatile for protecting against the toxic effects caused by oxidative stress. Ellagic acid, in aqueous solution at physiological pH, is able of deactivating a wide variety of free radicals, which is a desirable capability since in biological systems, these species are diverse. Under such conditions, the ellagic acid anion is proposed as the key species for its protective effects. It is predicted to be efficiently and continuously regenerated after scavenging two free radicals per cycle. This is an advantageous and unusual behavior that contributes to increase its antioxidant activity at low concentrations. In addition, the ellagic acid metabolites are also capable of efficiently scavenging a wide variety of free radicals. Accordingly, it is proposed that the ellagic acid efficiency for that purpose is not reduced after being metabolized. On the contrary, it provides continuous protection against oxidative stress through a free radical scavenging cascade. This is an uncommon and beneficial behavior, which makes ellagic acid particularly valuable to that purpose. After deprotonation, ellagic acid is also capable of chelating copper, in a concentration dependent way, decreasing the free radical production. In summary, ellagic acid is proposed to be an efficient multiple-function protector against oxidative stress.
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Affiliation(s)
- Annia Galano
- Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa , San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, C.P. 09340 México D. F., México
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Sinha VR, Sethi S. Pioglitazone hydrochloride: chemopreventive potential and development of site-specific drug delivery systems. Drug Deliv 2014; 22:408-17. [PMID: 24547712 DOI: 10.3109/10717544.2014.887156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The aim of this study was to investigate the potential of pioglitazone hydrochloride as a promising anticancer agent and then to design and evaluate the colon-targeted delivery system. The role of pioglitazone hydrochloride as a promising anticancer agent was evaluated by in vitro cell line studies and in vivo 1,2-dimethylhydrazine-induced colon carcinogenesis in rats. In order to deliver the drug at site of action, i.e. colon, drug embedded in matrices containing a release retarding polymer (HPMC K4M) and a polysaccharide (locust bean gum) were prepared. These matrix systems were further enteric coated with Eudragit®S100 to minimize the premature drug release in the upper segments of the GIT. In vitro dissolution studies were performed in absence and presence of rat caecal contents on selected batches and samples were analyzed using a validated RP-HPLC method. Hence, the studies led to the conclusion that successful site-specific delivery systems of pioglitazone hydrochloride were developed to improve its therapeutic efficacy in the management of colorectal cancer.
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Pandurangan AK, Ananda Sadagopan SK, Dharmalingam P, Ganapasam S. Luteolin, a bioflavonoid inhibits Azoxymethane-induced colorectal cancer through activation of Nrf2 signaling. Toxicol Mech Methods 2013; 24:13-20. [PMID: 24024667 DOI: 10.3109/15376516.2013.843111] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Colorectal cancer (CRC) is now perceived as a multistep process characterized by the accumulation of genetic alterations in oncogenes and tumor suppressor genes. Plant-derived compounds are receiving considerable attention for their potential role in reducing cancer risk. Luteolin, a bioflavonoid present in many fruits and vegetables, possesses antioxidant, anti-inflammatory and antiproliferative properties. This study was designed to investigate the possible role of luteolin administration on Phase 1 and 2 enzymes and NF-E2-related factor 2 (Nrf2)/keap1 pathway. Male Balb/C mice were divided into four groups: normal control, Azoxymethane (AOM)-induced, AOM-induced and luteolin treated, normal control treated with luteolin. CRC was induced by administration of AOM (15 mg/kg body weight) intraperitoneally (i.p.) once a week for three weeks. Luteolin administration (1.2 mg/kg body weight/day) significantly alleviated Phase1 enzymes in colon and liver, it increased the levels of phase 2 enzymes. Luteolin modulates the expressions of GST-α, µ and also the expression of Nrf2. Collectively, results of our hypothesis show that luteolin is a novel candidate for treating CRC.
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Affiliation(s)
- Ashok Kumar Pandurangan
- Department of Biochemistry, Cell Biology Lab, University of Madras , Chennai, Tamil Nadu , India
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Kumar KN, Raja SB, Vidhya N, Devaraj SN. Ellagic acid modulates antioxidant status, ornithine decarboxylase expression, and aberrant crypt foci progression in 1,2-dimethylhydrazine-instigated colon preneoplastic lesions in rats. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:3665-3672. [PMID: 22439659 DOI: 10.1021/jf204128z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Chemoprevention offers a novel approach to control the incidence of colorectal cancer (CRC), which is a fatal cause of malignancies in both Western and Asia countries. Ornithine decarboxylase (ODC) functions as a cell transition factor by regulating the biosynthesis of polyamines, which, allied with aberrant crypt foci (ACF) proliferation, cause early lesions of CRC. This study exemplifies the chemopreventive efficacy of ellagic acid (EA) in 1,2-dimethylhydrazine (DMH) initiated CRC in rats. Subcutaneous injection of DMH (40 mg/kg body weight twice a week for 2 weeks) to the rats resulted in elevated expression of ODC, a genetic marker for CRC, and its transcription factor myelocytomatosis oncogene (c-myc). Furthermore, increased levels of lipid peroxidation and hydroperoxides with diminished levels of antioxidants including superoxide dismutase, catalase, and reduced glutathione were also observed in the tissues of DMH-intoxicated rats. Oral supplementation of EA significantly influences maintenance of antioxidant status and transcriptional inactivation of ODC expression, reducing ACF proliferation and/or progression, thus signifying the chemopreventive efficacy of EA against CRC.
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Affiliation(s)
- Kasinathan Nirmal Kumar
- Department of Biochemistry, School of Life Sciences, Maraimalai (Guindy) campus, University of Madras, Chennai, Tamilnadu, India.
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Combinational Effects of Prebiotics and Soybean against Azoxymethane-Induced Colon Cancer In Vivo. J Nutr Metab 2011; 2011:868197. [PMID: 21961059 PMCID: PMC3180783 DOI: 10.1155/2011/868197] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2011] [Revised: 04/18/2011] [Accepted: 05/28/2011] [Indexed: 12/19/2022] Open
Abstract
Prebiotic fructans are nondigestible carbohydrates with numerous health benefits. Soybean is a rich source of phytonutrients such as isoflavones. The objective of this study was to evaluate the chemopreventive effects of prebiotics (Synergy1) and soybean meal (SM) at 5% and 10% levels alone and in combination on azoxymethane- (AOM-) induced colon carcinogenesis. After one wk of acclimatization, Fisher 344 male rats (N = 90) were randomly assigned to 9 groups (n = 10). Control rats (C) were fed AIN-93G/M. Two s/c injections of AOM were administered to rats at 7 and 8 wk of age at 16 mg/kg body weight. Rats were killed by CO(2) asphyxiation at 45 wk. Tumor incidence (%) in treatment groups ranged from 40 to 75 compared to 100 in C. Results indicate that feeding prebiotics and soybean in combination significantly reduced incidence of AOM-induced colon tumors with implications for food industry in the food-product development.
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Goodman M, Bostick RM, Kucuk O, Jones DP. Clinical trials of antioxidants as cancer prevention agents: past, present, and future. Free Radic Biol Med 2011; 51:1068-84. [PMID: 21683786 DOI: 10.1016/j.freeradbiomed.2011.05.018] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 05/09/2011] [Accepted: 05/17/2011] [Indexed: 02/07/2023]
Abstract
The purpose of this review is to summarize the most important human clinical trials of antioxidants as cancer prevention agents conducted to date, provide an overview of currently ongoing studies, and discuss future steps needed to advance research in this field. To date there have been several large (at least 7000 participants) trials testing the efficacy of antioxidant supplements in preventing cancer. The specific agents (diet-derived direct antioxidants and essential components of antioxidant enzymes) tested in those trials included β-carotene, vitamin E, vitamin C, selenium, retinol, zinc, riboflavin, and molybdenum. None of the completed trials produced convincing evidence to justify the use of traditional antioxidant-related vitamins or minerals for cancer prevention. Our search of ongoing trials identified six projects at various stages of completion. Five of those six trials use selenium as the intervention of interest delivered either alone or in combination with other agents. The lack of success to date can be explained by a variety of factors that need to be considered in the next generation research. These factors include lack of good biological rationale for selecting specific agents of interest; limited number of agents tested to date; use of pharmacological, rather than dietary, doses; and insufficient duration of intervention and follow-up. The latter consideration underscores the need for alternative endpoints that are associated with increased risk of neoplasia (i.e., biomarkers of risk), but are detectable prior to tumor occurrence. Although dietary antioxidants are a large and diverse group of compounds, only a small proportion of candidate agents have been tested. In summary, the strategy of focusing on large high-budget studies using cancer incidence as the endpoint and testing a relatively limited number of antioxidant agents has been largely unsuccessful. This lack of success in previous trials should not preclude us from seeking novel ways of preventing cancer by modulating oxidative balance. On the contrary, the well demonstrated mechanistic link between excessive oxidative stress and carcinogenesis underscores the need for new studies. It appears that future large-scale projects should be preceded by smaller, shorter, less expensive biomarker-based studies that can serve as a link from mechanistic and observational research to human cancer prevention trials. These relatively inexpensive studies would provide human experimental evidence for the likely efficacy, optimum dose, and long-term safety of the intervention of interest that would then guide the design of safe, more definitive large-scale trials.
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Affiliation(s)
- Michael Goodman
- Emory University Rollins School of Public Health, Atlanta, GA 30322, USA.
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Lee JH, Lee JS, Kim SE, Moon BS, Kim YC, Lee SK, Lee SK, Choi KY. Tautomycetin inhibits growth of colorectal cancer cells through p21cip/WAF1 induction via the extracellular signal-regulated kinase pathway. Mol Cancer Ther 2007; 5:3222-31. [PMID: 17172426 DOI: 10.1158/1535-7163.mct-06-0455] [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
Tautomycetin is an antifungal antibiotic retaining potent immunosuppressive function. We have identified the roles of tautomycetin on cellular proliferation and transformation of colorectal cancer cells. The proliferation and anchorage-independent growth of HCT-15, HT-29, and DLD-1 colorectal cancer cells were efficiently inhibited without induction of apoptosis by 150 nmol tautomycetin. These growth inhibitory effects were dependent on p21Cip/WAF induction via the extracellular signal-regulated kinase pathway, and the tautomycetin effects were abolished in HCT-116 colon cells and eight other types of cells that did not induce p21Cip/WAF by 150 nmol tautomycetin. The crucial role of p21Cip/WAF1 in the extracellular signal-regulated kinase pathway-dependent antiproliferative responses by tautomycetin was confirmed by using p21Cip/WAF1 gene-deleted HCT-116 cells. The growth inhibitory effect of tautomycetin was acquired by regulation of Raf-1 activity through inhibition of protein phosphatase type 1 and protein phosphatase type 2A with high preference toward protein phosphatase type 1. Tautomycetin could be a potential drug for colorectal cancer.
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Affiliation(s)
- Joon-Hee Lee
- National Research Laboratory of Molecular Complex Control, Yonsei University, Seoul, Korea
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Abstract
Colorectal cancer is one of a number of cancers that may be amenable to prevention. The NSAIDs (non-steroidal anti-inflammatory drugs) have been shown to be effective chemopreventative agents in humans, but their mechanism of action is not clear. The polyamines are cellular polycations that are essential for cell growth and are overproduced in cancer cells. It is our hypothesis that inhibition of polyamine metabolism is an integral part of the mechanism of cancer prevention mediated by NSAIDs.
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Affiliation(s)
- F R Saunders
- Department of Medicine and Therapeutics, University of Aberdeen, Polwarth Building, Foresterhill, Aberdeen, UK
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Sansbury LB, Millikan RC, Schroeder JC, North KE, Moorman PG, Keku TO, de Cotret AR, Player J, Sandler RS. COX-2 Polymorphism, Use of Nonsteroidal Anti-Inflammatory Drugs, and Risk of Colon Cancer in African Americans (United States). Cancer Causes Control 2006; 17:257-66. [PMID: 16489533 DOI: 10.1007/s10552-005-0417-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2005] [Accepted: 09/13/2005] [Indexed: 01/14/2023]
Abstract
INTRODUCTION The inducible Cyclooxygenase (COX)-2 enzyme plays an important role in inflammation and carcinogenesis. Recent reports suggest that single nucleotide polymorphisms (SNPs) in the COX-2 gene may alter enzyme function and in turn modify an individual's risk of colon cancer. We explored the association between the COX-2 Val511Ala SNP and risk of colon cancer among 240 African American cases and 326 African American controls in a population-based, case-control study in North Carolina. METHODS We used unconditional logistic regression models to determine the odds ratios (ORs) for genotype and risk of colon cancer. RESULTS We observed a non-statistically significant inverse association between any Ala COX-2 genotype and risk of colon cancer (OR = 0.62, 95% CI: 0.33, 1.16) among African Americans. The inverse association was present among non-regular NSAID users, use < or = 3 times/week, (OR = 0.66; 95% CI: 0.32, 1.37) and regular NSAID users, use > or =3 times/week for > or =3 months, (OR = 0.41; 95% CI: 0.11, 1.54). CONCLUSIONS Our results suggest that the COX-2 Val511Ala SNP does not antagonize the effect of NSAIDs on colon cancer risk and provides support that NSAID use and the COX-2 Val511Ala SNP may contribute to a reduced risk of colon cancer among African Americans.
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Affiliation(s)
- Leah B Sansbury
- Cancer Prevention Fellowship Program, Division of Cancer Prevention, National Cancer Institute, NIH, DHHS, Bethesda, MD 20892-8325, USA.
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Spiegel A, Hundley TR, Chen J, Gao J, Ouyang N, Liu X, Go MF, Tsioulias GJ, Kashfi K, Rigas B. NO-donating aspirin inhibits both the expression and catalytic activity of inducible nitric oxide synthase in HT-29 human colon cancer cells. Biochem Pharmacol 2005; 70:993-1000. [PMID: 16105666 DOI: 10.1016/j.bcp.2005.06.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2005] [Revised: 06/21/2005] [Accepted: 06/27/2005] [Indexed: 11/16/2022]
Abstract
Nitric oxide-releasing aspirin (NO-ASA) is emerging as a potentially important chemopreventive agent against colon cancer. We examined in HT-29 human colon adenocarcinoma cells the effect of NO-ASA on the inducible form of nitric oxide synthase (NOS2), an enzyme implicated in colon carcinogenesis. NO-ASA inhibited in a time- and concentration-dependent manner the expression of NOS2 up to 70% compared to control (IC50 for this effect = 46 microM). NO-ASA also decreased the corresponding steady-state mRNA levels and this reduction preceded the reduction of protein levels by at least 6 h. NO-ASA also reduced the enzymatic activity of NOS2, as determined by a direct enzyme assay (maximal reduction = 80%) and by determining the accumulation of NO in the culture medium (IC50 for this effect = 36 microM). These effects of NO-ASA on NOS2 were paralleled by inhibition in cell growth (IC50 = 8.5 microM). These findings indicate that NO-ASA profoundly inhibits both the expression and enzymatic activity of NOS2 and suggest that these effects may represent an important mechanism for the colon cancer chemopreventive effect of NO-ASA.
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Affiliation(s)
- Adam Spiegel
- Division of Cancer Prevention, SUNY at Stony Brook, Stony Brook, NY 11794-5200, USA
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Velayutham M, Villamena FA, Navamal M, Fishbein JC, Zweier JL. Glutathione-mediated formation of oxygen free radicals by the major metabolite of oltipraz. Chem Res Toxicol 2005; 18:970-5. [PMID: 15962931 DOI: 10.1021/tx049687h] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The major metabolite of the cancer chemopreventive oltipraz (1), a pyrrolopyrazine thione, 4, has been shown to be a phase two enzyme inducer, an activity thought to be a key to the cancer chemopreventive action of the parent compound. To understand the possible mechanism by which the metabolite acts as an inducer, a study of its potential to generate free radicals was undertaken. Electron paramagnetic resonance (EPR) spin trapping studies using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) were performed with 7-methyl-6,8-bis-methyldisulfanyl-pyrrolo[1,2-a]pyrazine, 5, a synthetic precursor to the metabolite in aqueous and organic solvents. In the presence of GSH, which rapidly liberates the metabolite from the precursor, a 1:2:2:1 quartet spectrum with hyperfine coupling constants a(N) = a(H) = 14.9 G, characteristic of the hydroxyl radical adduct of DMPO, was observed in the presence of oxygen. No signal was seen under anaerobic conditions. This signal was quenched by the addition of the superoxide scavenging enzyme Cu,Zn-superoxide dismutase. In aqueous dimethyl sulfoxide (80 vol % DMSO), the metabolite precursor 5, GSH, and DMPO exhibited an EPR spectrum with the hyperfine values of a(N) = 12.7 G, a(H1) = 10.3 G, and a(H2) = 1.3 G, corresponding to the superoxide radical adduct of DMPO. The amount of superoxide radical adduct formed from the reaction of 5 and GSH increases with GSH concentration in phosphate buffer solution. Kinetic studies show that the formation of superoxide radical anion is first-order with respect to GSH. The formation of superoxide radical anion by the metabolite in the presence of GSH is linear at lower concentrations of 5 but becomes nonlinear at high concentrations. Overall, these studies suggest a mechanism in which GSH reduces the metabolite 4 to 4. , presumably a radical anion, that in turn donates an electron to oxygen resulting in superoxide radical anion formation. This GSH stimulated redox cycle of the metabolite 4 suggests a possible mechanism by which the parent compound oltipraz might effect the cancer chemopreventive increase in the transcription of phase two enzymes that is mediated by transcription factor Nrf2.
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Affiliation(s)
- Murugesan Velayutham
- Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute,, The Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210, USA
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Sansbury LB, Millikan RC, Schroeder JC, Moorman PG, North KE, Sandler RS. Use of nonsteroidal antiinflammatory drugs and risk of colon cancer in a population-based, case-control study of African Americans and Whites. Am J Epidemiol 2005; 162:548-58. [PMID: 16093288 DOI: 10.1093/aje/kwi248] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
African Americans have the highest colon cancer incidence and mortality rates among all US ethnic groups. Epidemiologic studies suggest that use of nonsteroidal antiinflammatory drugs (NSAIDs) is associated with a reduced risk of colon cancer, but no study to date with adequate sample size has reported on the association among African Americans. The authors examined the association between NSAID use and risk of colon cancer in a population-based, case-control study in North Carolina that enrolled 731 African-American (294 cases, 437 controls) and 960 White (349 cases, 611 controls) participants between 1996 and 2000. Odds ratios were calculated using unconditional logistic regression for categories of NSAIDs and colon cancer risk. Inverse associations between regular NSAID use and colon cancer were similar for African Americans (odds ratio = 0.41, 95% confidence interval: 0.22, 0.77) and Whites (odds ratio = 0.48, 95% confidence interval: 0.28, 0.83) but stronger for women than men. Inverse associations were slightly weaker for occasional versus regular NSAID use, but they were similar for aspirin and nonaspirin NSAID use. These results add new knowledge suggesting that the protective effect of NSAIDs against colon cancer is similar among African Americans and Whites.
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Affiliation(s)
- Leah B Sansbury
- Cancer Prevention Fellowship Program, Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-8325, USA.
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Wolter F, Ulrich S, Stein J. Molecular mechanisms of the chemopreventive effects of resveratrol and its analogs in colorectal cancer: key role of polyamines? J Nutr 2004; 134:3219-22. [PMID: 15570015 DOI: 10.1093/jn/134.12.3219] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Resveratrol (3,4',5-trihydroxy-trans-stilbene), a phytoalexin found in grape skins, peanuts, and red wine, has been reported to exhibit a wide range of biological and pharmacological properties. It has been speculated that dietary resveratrol may act as an antioxidant, promote nitric oxide production, inhibit platelet aggregation, and increase high-density lipoprotein cholesterol and thereby serve as a cardioprotective agent (the so-called "French paradox"). Recently, it was demonstrated that resveratrol can function as a cancer chemopreventive agent, and there has been a great deal of experimental effort directed toward defining this effect. It has been shown that resveratrol and some of its analogues interfere with signal transduction pathways. Thus the activities of various protein kinases are inhibited, the expression of nuclear proto-oncogenes declines, and the activity of ornithine decarboxylase (ODC) is reduced. ODC, which catalyzes the rate-limiting step in the biosynthesis of polyamines, is closely linked with cellular proliferation and carcinogenesis. This review summarizes the recent advances that have provided new insights into the molecular mechanisms underlying the promising properties of resveratrol focusing on the key role of the polyamine metabolism in colorectal cancer cells.
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Affiliation(s)
- Freya Wolter
- 1st Department of Medicine, 2AFES, J. W. Goethe University, 60590 Frankfurt/Main, Germany
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Fallone F, Villard PH, Sérée E, Rimet O, Nguyen QB, Bourgarel-Rey V, Fouchier F, Barra Y, Durand A, Lacarelle B. Retinoids repress Ah receptor CYP1A1 induction pathway through the SMRT corepressor. Biochem Biophys Res Commun 2004; 322:551-6. [PMID: 15325265 DOI: 10.1016/j.bbrc.2004.07.153] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Indexed: 10/26/2022]
Abstract
CYP1A1 isoform is mainly regulated by the transcription factor AhR and to a lesser extent by the nuclear receptor RAR. The effect of a coexposure with 3MC, a AhR ligand, and RA, a RAR ligand, which are, respectively, strong and weak CYP1A1 inducers, is poorly known. We showed in Caco-2 cells that addition of RA significantly decreased 3MC-induced CYP1A1 expression by -55% for mRNA level and -30% for promoter and enzymatic activities. We further showed that RA decreased AhR protein level. Moreover, a physical interaction between AhR and the RAR-corepressor SMRT has been described in vitro. Using the corepressor inhibitor TSA, transfected-cells with SMRT cDNA, and coimmunoprecipitation experiments, we demonstrated that RA addition repressed AhR function through a marked AhR/SMRT physical interaction. This interaction explains the decrease of 3MC-induced CYP1A1 expression. This new mechanism involving the repression of AhR-induced CYP1A1 expression by retinoids allows better knowledge of the CYP1A1 regulation.
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Affiliation(s)
- Frédérique Fallone
- FRE CNRS 2737, Faculté de Pharmacie, Université de la Méditerranée, 27 Bd Jean Moulin, 13385 Marseille Cedex 05, France
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16
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Koornstra JJ, de Jong S, Hollema H, de Vries EGE, Kleibeuker JH. Changes in apoptosis during the development of colorectal cancer: a systematic review of the literature. Crit Rev Oncol Hematol 2003; 45:37-53. [PMID: 12482571 DOI: 10.1016/s1040-8428(01)00228-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The development of colorectal cancer is characterised by an accumulation of molecular genetic alterations causing disorders in cell growth, differentiation and apoptosis. Although changes in apoptosis with colorectal cancer development have been studied extensively, a clear consensus of opinion has not yet emerged. In this review, the literature about changes in the frequency and distribution of apoptosis in tissue sections of normal and neoplastic colorectal tissues was reviewed systematically. Using a PUBMED search, 53 relevant articles were identified. Data from these studies are discussed with respect to the following aspects: methods used to detect apoptotic cell death; frequency and locoregional distribution of apoptosis in normal mucosa, adenomas and carcinomas; the correlation between levels of apoptosis and proliferation and the prognostic significance of the degree of apoptosis in colorectal cancer. Possible underlying mechanisms of dysregulation of apoptosis are discussed briefly. Finally, possible therapeutic implications of knowledge of the molecular regulation of apoptosis are discussed and potential options for further research are suggested.
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Affiliation(s)
- J J Koornstra
- Department of Medical Oncology, University Hospital, P.O. Box 30.001, 9700 RB Groningen, The Netherlands
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17
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Prevention and Chemoprevention of Colorectal Neoplasms. COLORECTAL CANCER 2002. [DOI: 10.1007/978-3-642-56008-8_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Abstract
Main purpose of the review is to analyse the impact of the current approaches for colorectal cancer prevention, including chemoprevention. Available evidence does not support the contention that a more appropriate diet can be of great help in the prevention of these neoplasms, either because the scientific evidence is poor and highly controversial, or because changes in diet are difficult to implement, at least in many Western countries. Similarly, a preventive approach based on the modification of lifestyle remains improbable, either in the short --or in the long period of time. Secondary prevention--i.e., the systematic removal of adenomatous polyps--can hardly be applied in the general population, with the exception of individuals at risk because members of families with Adenomatosis coli or Lynch syndrome, or affected by inflammatory bowel diseases. Finally, chemoprevention (i.e., the attempt to prevent tumour development through the administration of drugs or natural compounds that interfere with various phases of carcinogenesis) is still in its infancy Though attractive, this approach requires well-designed studies which should be carried out for years before being evaluated and interpreted; so far most of these investigations gave inconsistent or controversial results. In conclusion, both primary and secondary prevention of colorectal malignancies appear difficult to apply in the general population, and chemoprevention is still at the beginning of a (presumably] long story. The final impression is that notwithstanding the remarkable advancements made in the last two decades in colorectal cancer research, the practical application of these new concepts remains difficult.
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Affiliation(s)
- DeLeonM Ponz
- Department of Medical, Oncological and Radiological Science, University of Modena and Reggio Emilia, Italy.
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Galati G, Teng S, Moridani MY, Chan TS, O'Brien PJ. Cancer chemoprevention and apoptosis mechanisms induced by dietary polyphenolics. DRUG METABOLISM AND DRUG INTERACTIONS 2001; 17:311-49. [PMID: 11201302 DOI: 10.1515/dmdi.2000.17.1-4.311] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This review summarises current knowledge on the various molecular chemopreventive or therapeutic mechanisms that may be involved when the administration of flavonoids or polyphenols prevented chemical carcinogenesis in animal models. These mechanisms can be subdivided into the following: 1) the molecular mechanisms involved in preventing carcinogen metabolic activation, 2) the molecular mechanisms for preventing tumour cell proliferation by inactivation or downregulation of prooxidant enzymes or signal transduction enzymes, 3) the molecular cell death mechanisms for the induction of tumour cell death (apoptosis) and the molecular mechanisms for the inhibition of isolated mitochondria functions. Many of the flavonoids and polyphenols found in diets, supplements or herbal medicine were also ranked using "accelerated cytotoxic mechanism screening" by a combinatorial approach utilising isolated rat hepatocytes. A strong correlation of an early collapse of the mitochondrial membrane potential and cell death was found for most of the cytotoxic polyphenols but did not occur with non-toxic polyphenols. This screening could prove useful for eliminating polyphenols that have the potential for adverse health effects and for selecting safe and effective polyphenolic candidates for further development as supplements for preventing cancer or cardiovascular disease. Safety concerns of flavonoid/polyphenol supplements are also reviewed.
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Affiliation(s)
- G Galati
- Department of Pharmacology, University of Toronto, Ontario, Canada
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