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Wu R, Li S, Sargsyan D, Yin R, Kuo HC, Peter R, Wang L, Hudlikar R, Liu X, Kong AN. DNA methylome, transcriptome, and prostate cancer prevention by phenethyl isothiocyanate in TRAMP mice. Mol Carcinog 2021; 60:391-402. [PMID: 33848375 PMCID: PMC8201649 DOI: 10.1002/mc.23299] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 12/28/2022]
Abstract
Epigenetics/epigenomics has been shown to be involved in carcinogenesis. However, how the epigenome would be altered in the transgenic adenocarcinoma of the mouse prostate (TRAMP) cancer model and the effect of cancer chemopreventive phytochemical phenethyl isothiocyanate (PEITC) on the epigenome in TRAMP mice are not known. PEITC has been reported to reduce the risk of many cancers including prostate cancer (PCa). In this study, male TRAMP mice were fed a control diet or diet containing 0.05% PEITC from 8 weeks to 16 weeks. The tumor incidence was reduced in the PEITC diet (0/6) as compared with the control diet (6/7). RNA-sequencing (RNA-seq) analyses on nontumor and tumor prostatic tissues revealed several pathways like cell cycle/Cdc42 signaling, inflammation, and cancer-related signaling, were activated in prostate tissues of TRAMP mice but were reversed or attenuated in TRAMP mice fed with PEITC diet. DNA CpG methyl-seq analyses showed that global methylation patterns of prostate samples from TRAMP mice were hugely different from those of wild-type mice. Dietary PEITC partially reversed the global methylation changes during prostatic carcinogenesis. Integration of RNA-seq and DNA methyl-seq analyses identified a list of genes, including Adgrb1 and Ebf4, with an inverse regulatory relationship between their RNA expression and CpG methylation. In summary, our current study demonstrates that alteration of the global epigenome in TRAMP prostate tumor and PEITC administration suppresses PCa carcinogenesis, impacts global CpG epigenome and transcriptome, and attenuates carcinogenic pathways like cell cycle arrest and inflammation. These results may provide insights and epigenetic markers/targets for PCa prevention and treatment in human PCa patients.
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Affiliation(s)
- Renyi Wu
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Shanyi Li
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Davit Sargsyan
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Ran Yin
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Hsiao-Chen Kuo
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Rebecca Peter
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Lujing Wang
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Rasika Hudlikar
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Xia Liu
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Ah-Ng Kong
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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Mukherjee A, Park A, Wang L, Davies KP. Role of opiorphin genes in prostate cancer growth and progression. Future Oncol 2021; 17:2209-2223. [PMID: 33593085 PMCID: PMC8293029 DOI: 10.2217/fon-2020-1299] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 02/04/2021] [Indexed: 01/02/2023] Open
Abstract
Background: We describe the first studies investigating a role for opiorphin genes (PROL1, SMR3A and SMR3B) in prostate cancer (PrCa). Materials & methods: Databases and PrCa tissue arrays were screened for opiorphin expression. Xenografted tumor growth of human PrCa cells overexpressing PROL1 was compared with controls in nude mice. Modulated gene expression by overexpression of PROL1 was determined by RNA sequencing. Results: PrCa is associated with overexpression of opiorphin genes. Xenografted androgen-sensitive PrCa cells overexpressing PROL1 developed into tumors in castrated male mice (in contrast to parental cells). PROL1 overexpression modulates expression of genes in angiogenesis, steroid and hypoxic response pathways. Conclusions: Opiorphins promote the development of androgen-insensitive PrCa and activate pathways that potentially overcome the hypoxic barrier generated during tumor growth.
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Affiliation(s)
- Amarnath Mukherjee
- Department of Urology, Albert Einstein College of Medicine/Montefiore Medical Center, NY 10461, USA
| | - Augene Park
- Department of Urology, Albert Einstein College of Medicine/Montefiore Medical Center, NY 10461, USA
| | - Li Wang
- Department of Urology, Albert Einstein College of Medicine/Montefiore Medical Center, NY 10461, USA
| | - Kelvin P Davies
- Department of Urology, Albert Einstein College of Medicine/Montefiore Medical Center, NY 10461, USA
- Department of Physiology & Biophysics, Albert Einstein College of Medicine/Montefiore Medical Center, NY 10461, USA
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3
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Sato C, Kaneko S, Sato A, Virgona N, Namiki K, Yano T. Combination Effect of δ-Tocotrienol and γ-Tocopherol on Prostate Cancer Cell Growth. J Nutr Sci Vitaminol (Tokyo) 2018; 63:349-354. [PMID: 29225320 DOI: 10.3177/jnsv.63.349] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Tocotrienols (T3s) and tocopherols (Tocs) are both members of the vitamin E family. It is known that δ-tocotrienol (δ-T3) has displayed the most potent anti-cancer activity amongst the tocotrienols. On the other hand, γ-tocopherol (γ-Toc) is reported to have a protective effect against prostate cancer. Therefore, we investigated whether the combination of γ-Toc and δ-T3 could strengthen the inhibitory effect of δ-T3 on prostate cancer cell growth. In this study the effect of combined δ-T3 (annatto T3 oil) and γ-Toc (Tmix, γ-Toc-rich oil) therapy was assessed against human androgen-dependent prostate cancer cells (LNCaP). We found that combined treatment of δ-T3 (10 μM) and γ-Toc (5 μM) resulted in reinforced anti-prostate cancer activity. Specifically, cell cycle phase distribution analysis revealed that in addition to G1 arrest caused by the treatment with δ-T3, the combination of δ-T3 with γ-Toc induced G2/M arrest. Enhanced induction of apoptosis by the combined treatment was also observed. These findings indicate that combination of δ-T3 and γ-Toc significantly inhibits prostate cancer cell growth due to the simultaneous cell cycle arrest in the G1 phase and G2/M phase.
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Affiliation(s)
- Chiaki Sato
- Graduate School of Food and Nutritional Sciences, Toyo University
| | - Saki Kaneko
- Graduate School of Food and Nutritional Sciences, Toyo University
| | - Ayami Sato
- Research Institute of Life Innovation, Toyo University
| | | | - Kozue Namiki
- Graduate School of Science and Engineering, Saitama University
| | - Tomohiro Yano
- Graduate School of Food and Nutritional Sciences, Toyo University.,Research Institute of Life Innovation, Toyo University
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Wang H, Yang X, Liu A, Wang G, Bosland MC, Yang CS. δ-Tocopherol inhibits the development of prostate adenocarcinoma in prostate specific Pten-/- mice. Carcinogenesis 2018; 39:158-169. [PMID: 29121168 PMCID: PMC5862254 DOI: 10.1093/carcin/bgx128] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The PTEN/PI3K/AKT axis plays a critical role in regulating cell growth, differentiation and survival. Activation of this signaling pathway is frequently found in human cancers. Our previous studies demonstrated that δ-tocopherol (δ-T) attenuates the activation of AKT by growth factor in prostate cancer cell lines, leading to inhibition of proliferation and induction of apoptosis. Herein, we investigated whether δ-T inhibits the development of prostate adenocarcinoma in prostate-specific Pten-/- (Ptenp-/-) mice in which the activation of AKT is the major driving force for tumorigenesis. By feeding Ptenp-/- mice with AIN93M or 0.2% δ-T supplemented diet starting at the age of 6 or 12 weeks, we found that δ-T treatment reduced prostate adenocarcinoma multiplicity at the age of 40 weeks by 53.3 and 42.7%, respectively. Immunohistochemical (IHC) analysis demonstrated that the phosphorylation of AKT (T308) was reduced in the prostate of the mice administered the δ-T diet. Consistently, proliferation was reduced and apoptosis was increased in prostate lesions of mice on the δ-T diet. Oxidative stress, as determined by IHC staining of 8-OH-dG, was not altered during prostate tumorigenesis, nor was it affected by administration of δ-T. In contrast, α-tocopherol (α-T) at 0.2% in the diet did not affect prostate adenocarcinoma multiplicity in the Ptenp-/- mice. This finding is consistent with data from our previous study that δ-T, but not α-T, inhibits the activation of AKT and the growth of prostate cancer cells. Together, these results demonstrate that δ-T inhibits the development of prostate adenocarcinoma in Ptenp-/- mice, mainly through inhibition of AKT activation.
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Affiliation(s)
- Hong Wang
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, USA
| | - Xu Yang
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, USA
| | - Anna Liu
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, USA
| | - Guocan Wang
- Department of Cancer Biology, MD Anderson Cancer Center, Houston, USA
| | - Maarten C Bosland
- Department of Pathology, College of Medicine, University of Illinois at Chicago, Chicago, USA
| | - Chung S Yang
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, USA
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Taxifolin Activates the Nrf2 Anti-Oxidative Stress Pathway in Mouse Skin Epidermal JB6 P+ Cells through Epigenetic Modifications. Int J Mol Sci 2017; 18:ijms18071546. [PMID: 28714938 PMCID: PMC5536034 DOI: 10.3390/ijms18071546] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/04/2017] [Accepted: 07/07/2017] [Indexed: 12/31/2022] Open
Abstract
Nuclear factor erythroid-2 related factor 2 (Nrf2) is a vital transcription factor that regulates the anti-oxidative defense system. Previous reports suggested that the expression of the Nrf2 gene can be regulated by epigenetic modifications. The potential epigenetic effect of taxifolin (TAX), a potent cancer chemopreventive agent, in skin cancer chemoprotection is unknown. In this study, we investigated how Nrf2 is epigenetically regulated by TAX in JB6 P+ cells. TAX was found to inhibit the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced colony formation of JB6 P+ cells. TAX induced antioxidant response element (ARE)-luciferase activity in HepG2-C8 cells and up-regulated mRNA and protein levels of Nrf2 and its downstream genes heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1), in JB6 P+ cells. Furthermore, bisulfite genomic sequencing revealed that TAX treatment reduces the methylation level of the first 15 CpGs sites in the Nrf2 promoter. Western blotting showed that TAX inhibits the expression levels of DNA methyltransferase (DNMT) and histone deacetylase (HDAC) proteins. In summary, our results revealed that TAX can induce expression of Nrf2 and its downstream target genes in JB6 P+ cells by CpG demethylation. These finding suggest that TAX may exhibit a skin cancer preventive effect by activating Nrf2 via an epigenetic pathway.
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Bak MJ, Das Gupta S, Wahler J, Lee HJ, Li X, Lee MJ, Yang CS, Suh N. Inhibitory Effects of γ- and δ-Tocopherols on Estrogen-Stimulated Breast Cancer In Vitro and In Vivo. Cancer Prev Res (Phila) 2017; 10:188-197. [PMID: 28096236 DOI: 10.1158/1940-6207.capr-16-0223] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 12/24/2016] [Accepted: 01/03/2017] [Indexed: 12/21/2022]
Abstract
Estrogens have been implicated as complete carcinogens for breast and other tissues through mechanisms involving increased cell proliferation, oxidative stress, and DNA damage. Because of their potent antioxidant activity and other effects, tocopherols have been shown to exert antitumor activities in various cancers. However, limited information is available on the effect of different forms of tocopherols in estrogen-mediated breast cancer. To address this, we examined the effects of α-, γ-, and δ-tocopherols as well as a natural γ-tocopherol-rich mixture of tocopherols, γ-TmT, on estrogen-stimulated MCF-7 cells in vitro and in vivo For the in vivo studies, MCF-7 cells were injected into the mammary fat pad of immunodeficient mice previously implanted with estrogen pellets. Mice were then administered diets containing 0.2% α-, γ-, δ-tocopherol, or γ-TmT for 5 weeks. Treatment with α-, γ-, δ-tocopherols, and γ-TmT reduced tumor volumes by 29% (P < 0.05), 45% (P < 0.05), 41% (P < 0.05), and 58% (P < 0.01), as well as tumor weights by 20%, 37% (P < 0.05), 39% (P < 0.05), and 52% (P < 0.05), respectively. γ- and δ-tocopherols and γ-TmT inhibited the expression of cell proliferation-related genes such as cyclin D1 and c-Myc, and estrogen-related genes such as TFF/pS2, cathepsin D, and progesterone receptor in estrogen-stimulated MCF-7 cells in vitro Further, γ- and δ-tocopherols decreased the levels of estrogen-induced oxidative stress and nitrosative stress markers, 8-hydroxy-2'-deoxyguanosine and nitrotyrosine, as well as the DNA damage marker, γ-H2AX. Our results suggest that γ- and δ-tocopherols and the γ-tocopherol-rich mixture are effective natural agents for the prevention and treatment of estrogen-mediated breast cancer. Cancer Prev Res; 10(3); 188-97. ©2017 AACR.
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Affiliation(s)
- Min Ji Bak
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Soumyasri Das Gupta
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Joseph Wahler
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Hong Jin Lee
- Department of Food Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Xiaowei Li
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Mao-Jung Lee
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Chung S Yang
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey
| | - Nanjoo Suh
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey.
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey
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Chen JX, Liu A, Lee MJ, Wang H, Yu S, Chi E, Reuhl K, Suh N, Yang CS. δ- and γ-tocopherols inhibit phIP/DSS-induced colon carcinogenesis by protection against early cellular and DNA damages. Mol Carcinog 2017; 56:172-183. [PMID: 27175800 PMCID: PMC5647579 DOI: 10.1002/mc.22481] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/18/2016] [Accepted: 03/01/2016] [Indexed: 12/25/2022]
Abstract
Tocopherols, the major forms of vitamin E, are a family of fat-soluble compounds that exist in alpha (α-T), beta (β-T), gamma (γ-T), and delta (δ-T) variants. A cancer preventive effect of vitamin E is suggested by epidemiological studies. However, past animal studies and human intervention trials with α-T, the most active vitamin E form, have yielded disappointing results. A possible explanation is that the cancer preventive activity of α-T is weak compared to other tocopherol forms. In the present study, we investigated the effects of δ-T, γ-T, and α-T (0.2% in diet) in a novel colon cancer model induced by the meat-derived dietary carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and promoted by dextran sodium sulfate (DSS)-induced colitis in CYP1A-humanized (hCYP1A) mice. PhIP/DSS treatments induced multiple polypoid tumors, mainly tubular adenocarcinomas, in the middle to distal colon of the hCYP1A mice after 10 wk. Dietary supplementation with δ-T and γ-T significantly reduced colon tumor formation and suppressed markers of oxidative and nitrosative stress (i.e., 8-oxo-dG and nitrotyrosine) as well as pro-inflammatory mediators (i.e., NF-κB p65 and p-STAT3) in tumors and adjacent tissues. By administering δ-T at different time periods, we obtained results suggesting that the inhibitory effect of δ-T against colon carcinogenesis is mainly due to protection against early cellular and DNA damages caused by PhIP. α-T was found to be ineffective in inhibiting colon tumors and less effective in attenuating the molecular changes. Altogether, we demonstrated strong cancer preventive effects of δ-T and γ-T in a physiologically relevant model of human colon cancer. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Jayson X. Chen
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, New Jersey
| | - Anna Liu
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, New Jersey
| | - Mao-Jung Lee
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, New Jersey
| | - Hong Wang
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, New Jersey
| | - Siyuan Yu
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, New Jersey
| | - Eric Chi
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, New Jersey
| | - Kenneth Reuhl
- Department of Pharmacology and Toxicology, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Nanjoo Suh
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, New Jersey
- Cancer Institute of New Jersey, New Brunswick, NJ 08903, USA
| | - Chung S. Yang
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, New Jersey
- Cancer Institute of New Jersey, New Brunswick, NJ 08903, USA
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KRUK J, ABOUL-ENEIN H. What Are the Links of Prostate Cancer with Physical Activity and Nutrition? : A Systematic Review Article. IRANIAN JOURNAL OF PUBLIC HEALTH 2016; 45:1558-1567. [PMID: 28053921 PMCID: PMC5207096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
BACKGROUND Prostate cancer (PCa) is the second most common malignancy in men worldwide. The purpose of this study was to provide a brief synthesis the current knowledge for the effects of physical activity (PA) and nutrition on PCa risk. METHODS A systematic review of English languages reviews, meta-analysis, and original articles published from 2009 to 2015 extracted from the following websites: MEDLINE, Web of Science, Health Source, Science Direct, and their references. RESULTS The review of the literature led to the selection of 12 review or meta-analysis studies and 15 lately published observational studies. Most of studies reported relationship of recreational and occupational PA and vegetables, fruits, vitamins, red/processed meats, and fats consumption with risk of PCa. Decreased risk for PCa associated with exercise was reported in seven of the ten articles on this topic. The inverse association of vegetables and/or fruit intake with PCa risk was reported in eight of 13 papers. The effect of meat/fat intake on PCa was estimated in four articles finding increased risk. There was heterogeneity between studies, and findings are inconsistent. CONCLUSION Physical activity does not significantly reduce the risk of PCa; however, vigorous exercise may reduce the risk of aggressive tumor. Besides, there is a lack of definitive evidence supporting the preventive role of diet against PCa. Due to many other benefits of regular moderate-vigorous PA and a diet high in vegetables and fruits and low in red/processed meats and fats, these lifestyle patterns may be recommended.
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Affiliation(s)
- Joanna KRUK
- Dept. of Prevention and Occupational Therapy, Faculty of Physical Culture and Health Promotion, University of Szczecin, Szczecin, Poland,Corresponding Author:
| | - Hassan ABOUL-ENEIN
- Dept. of Pharmaceutical and Medicinal Chemistry, Pharmaceutical and Drug Industries Research Division, National Research Center, Dokki, Giza, Egypt
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Das Gupta S, Suh N. Tocopherols in cancer: An update. Mol Nutr Food Res 2016; 60:1354-63. [PMID: 26751721 DOI: 10.1002/mnfr.201500847] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 12/23/2015] [Accepted: 12/28/2015] [Indexed: 12/16/2022]
Abstract
Tocopherols exist in four forms designated as α, β, δ, and γ. Due to their strong antioxidant properties, tocopherols have been suggested to reduce the risk of cancer. Cancer prevention studies with tocopherols have mostly utilized α-tocopherol. Large-scale clinical trials with α-tocopherol provided inconsistent results regarding the cancer-preventive activities of tocopherols. This review summarizes our current understanding of the anticancer activities of different forms of tocopherols based on follow-up of the clinical trials, recent epidemiological evidences, and experimental studies using in vitro and in vivo models. The experimental data provide strong evidence in support of the anticancer activities of δ-tocopherol, γ-tocopherol, and the natural tocopherol mixture rich in γ-tocopherol, γ-TmT, over α-tocopherol. Such outcomes emphasize the need for detailed investigation into the cancer-preventive activities of different forms of tocopherols to provide a strong rationale for intervention studies in the future.
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Affiliation(s)
- Soumyasri Das Gupta
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Nanjoo Suh
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, USA.,Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
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Chen JX, Li G, Wang H, Liu A, Lee MJ, Reuhl K, Suh N, Bosland MC, Yang CS. Dietary tocopherols inhibit PhIP-induced prostate carcinogenesis in CYP1A-humanized mice. Cancer Lett 2015; 371:71-8. [PMID: 26582657 DOI: 10.1016/j.canlet.2015.11.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/05/2015] [Accepted: 11/05/2015] [Indexed: 12/25/2022]
Abstract
Tocopherols, the major forms of vitamin E, exist as alpha-tocopherol (α-T), β-T, γ-T and δ-T. The cancer preventive activity of vitamin E is suggested by epidemiological studies, but recent large-scale cancer prevention trials with high dose of α-T yielded disappointing results. Our hypothesis that other forms of tocopherols have higher cancer preventive activities than α-T was tested, herein, in a novel prostate carcinogenesis model induced by 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP), a dietary carcinogen, in the CYP1A-humanized (hCYP1A) mice. Treatment of hCYP1A mice with PhIP (200 mg/kg b.w., i.g.) induced high percentages of mouse prostatic intraepithelial neoplasia (mPIN), mainly in the dorsolateral glands. Supplementation with a γ-T-rich mixture of tocopherols (γ-TmT, 0.3% in diet) significantly inhibited the development of mPIN lesions and reduced PhIP-induced elevation of 8-oxo-deoxyguanosine, COX-2, nitrotyrosine, Ki-67 and p-AKT, and the loss of PTEN and Nrf2. Further studies with purified δ-T, γ-T or α-T (0.2% in diet) showed that δ-T was more effective than γ-T or α-T in preventing mPIN formations and p-AKT elevation. These results indicate that γ-TmT and δ-T could be effective preventive agents of prostate cancer.
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Affiliation(s)
- Jayson X Chen
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Piscataway, NJ, USA; Joint Graduate Program in Toxicology, Piscataway, NJ, USA
| | - Guangxun Li
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Piscataway, NJ, USA
| | - Hong Wang
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Piscataway, NJ, USA
| | - Anna Liu
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Piscataway, NJ, USA
| | - Mao-Jung Lee
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Piscataway, NJ, USA
| | - Kenneth Reuhl
- Department of Pharmacology and Toxicology, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Nanjoo Suh
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Piscataway, NJ, USA; Cancer Institute of New Jersey, New Brunswick, NJ 08903, USA
| | - Maarten C Bosland
- Department of Pathology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Chung S Yang
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Piscataway, NJ, USA; Cancer Institute of New Jersey, New Brunswick, NJ 08903, USA.
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11
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Wang H, Hong J, Yang CS. δ-Tocopherol inhibits receptor tyrosine kinase-induced AKT activation in prostate cancer cells. Mol Carcinog 2015; 55:1728-1738. [PMID: 26465359 DOI: 10.1002/mc.22422] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 09/03/2015] [Accepted: 10/02/2015] [Indexed: 12/31/2022]
Abstract
The cancer preventive activity of vitamin E is suggested by epidemiological studies and supported by animal studies with vitamin E forms, γ-tocopherol and δ-tocopherol (δ-T). Several recent large-scale cancer prevention trials with high dose of α-tocopherol, however, yielded disappointing results. Whether vitamin E prevents or promotes cancer is a serious concern. A better understanding of the molecular mechanisms of action of the different forms of tocopherols would enhance our understanding of this topic. In this study, we demonstrated that δ-T was the most effective tocopherol form in inhibiting prostate cancer cell growth, by inducing cell cycle arrest and apoptosis. By profiling the effects of δ-T on the cell signaling using the phospho-kinase array, we found that the most inhibited target was the phosphorylation of AKT on T308. Further study on the activation of AKT by EGFR and IGFR revealed that δ-T attenuated the EGF/IGF-induced activation of AKT (via the phosphorylation of AKT on T308 induced by the activation of PIK3). Expression of dominant active PIK3 and AKT in prostate cancer cell line DU145 in which PIK3, AKT, and PTEN are wild type caused the cells to be reflectory to the inhibition of δ-T, supporting that δ-T inhibits the PIK3-mediated activation of AKT. Our data also suggest that δ-T interferes with the EGF-induced EGFR internalization, which leads to the inhibition of the receptor tyrosine kinase-dependent activation of AKT. In summary, our results revealed a novel mechanism of δ-T in inhibiting prostate cancer cell growth, supporting the cancer preventive activity δ-T. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Hong Wang
- Susan L. Cullman Laboratory for Cancer Research, Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey.
| | - Jungil Hong
- Susan L. Cullman Laboratory for Cancer Research, Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey.,Department of Food Science and Technology, College of Natural Science, Seoul Women's University, Seoul, Korea
| | - Chung S Yang
- Susan L. Cullman Laboratory for Cancer Research, Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey.
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12
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Abstract
In this perspective, modifiable carcinogenic factors for the prostate are summarized. This is followed by a discussion of how current knowledge about causation of prostate cancer and chemoprevention of prostate cancer can be used to develop preventive strategies. Prostate cancer is a slowly developing cancer which offers opportunities for preventive interventions. Only a few randomized clinical trials of prostate cancer prevention have been completed. The SELECT study with selenium and vitamin E did not find protective effects, but in two trials with 5α-reductase inhibitors risk was reduced about 25%, showing that chemoprevention is possible and indicating that the androgen receptor is a suitable target. Besides smoking cessation and reduction of obesity, there are no known dietary or life style interventions that will have a major impact on prostate cancer risk. Inflammation of the prostate is an attractive target and aspirin may be a promising candidate agent, but has not been addressed yet in preclinical and clinical studies. Antioxidants other than selenium and vitamin E are unlikely to be very effective and data on several dietary supplements are not encouraging. More candidate agents need to be identified and tested in relevant and adequate preclinical models and Phase II trials that have predictive value for outcome of Phase III randomized studies. Doing this will require a systematic approach comparing preclinical and clinical study outcomes to determine their predictive value of preventive efficacy.
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13
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Huang H, Chen S, Van Doren J, Li D, Farichon C, He Y, Zhang Q, Zhang K, Conney AH, Goodin S, Du Z, Zheng X. α-Tomatine inhibits growth and induces apoptosis in HL-60 human myeloid leukemia cells. Mol Med Rep 2015; 11:4573-8. [PMID: 25625536 PMCID: PMC4735690 DOI: 10.3892/mmr.2015.3238] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 11/07/2014] [Indexed: 11/18/2022] Open
Abstract
α-tomatine is a glycoalkaloid that occurs naturally in tomatoes (Lycopersicon esculentum). In the present study, the effects of α-tomatine on human myeloid leukemia HL-60 cells were investigated. Treatment of HL-60 cells with α-tomatine resulted in growth inhibition and apoptosis in a concentration-dependent manner. Tomatidine, the aglycone of tomatine had little effect on the growth and apoptosis of HL-60 cells. Growth inhibition and apoptosis induced by α-tomatine in HL-60 cells was partially abrogated by addition of cholesterol indicating that interactions between α-tomatine and cell membrane-associated cholesterol may be important in mediating the effect of α-tomatine. Activation of nuclear factor-κB by the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate failed to prevent apoptosis in HL-60 cells treated with α-tomatine. In animal experiments, it was found that treatment of mice with α-tomatine inhibited the growth of HL-60 xenografts in vivo. Results from the present study indicated that α-tomatine may have useful anti-leukemia activities.
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Affiliation(s)
- Huarong Huang
- Allan H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou, Guangdong 510006, P.R. China
| | - Shaohua Chen
- Department of Otolaryngology, Guangdong Provincial People's Hospital, Guangzhou, Guangdong 510006, P.R. China
| | - Jeremiah Van Doren
- Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Dongli Li
- Allan H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou, Guangdong 510006, P.R. China
| | - Chelsea Farichon
- Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Yan He
- Allan H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou, Guangdong 510006, P.R. China
| | - Qiuyan Zhang
- Allan H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou, Guangdong 510006, P.R. China
| | - Kun Zhang
- Allan H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou, Guangdong 510006, P.R. China
| | - Allan H Conney
- Allan H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou, Guangdong 510006, P.R. China
| | - Susan Goodin
- Division of Medical Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ 08903, USA
| | - Zhiyun Du
- Allan H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou, Guangdong 510006, P.R. China
| | - Xi Zheng
- Allan H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou, Guangdong 510006, P.R. China
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14
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Huang H, He Y, Cui XX, Goodin S, Wang H, Du ZY, Li D, Zhang K, Tony Kong AN, DiPaola RS, Yang CS, Conney A, Zheng X. Potent inhibitory effect of δ-tocopherol on prostate cancer cells cultured in vitro and grown as xenograft tumors in vivo. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:10752-8. [PMID: 25322450 PMCID: PMC4334301 DOI: 10.1021/jf504058f] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
In the present study, the effects of δ-tocopherol (δ-T) on growth and apoptosis of human prostate cancer cells were determined and compared with that of α-tocopherol (α-T), a commonly used form of vitamin E. Treatment of human prostate cancer cells with δ-T resulted in strong growth inhibition and apoptosis stimulation, while the effects of α-T were modest. The strong effects of δ-T on the cells were associated with suppression of androgen receptor (AR) activity and decreased level of prostate specific antigen (PSA) that is a downstream target of the AR signaling. In the in vivo study, we found that δ-T had a more potent inhibitory effect on the formation and growth of prostate xenograft tumors than that of α-T. Moreover, δ-T inhibited proliferation and stimulated apoptosis in the tumors. The present study identified δ-T as a better form of vitamin E than α-T for future clinical studies of prostate cancer prevention.
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Affiliation(s)
- Huarong Huang
- Allan
H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou 510006, People’s
Republic of China
| | - Yan He
- Allan
H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou 510006, People’s
Republic of China
| | - Xiao-Xing Cui
- Susan
Lehman Cullman Laboratory for Cancer Research, Department of Chemical
Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Susan Goodin
- Rutgers
Cancer Institute of New Jersey, New Brunswick, New Jersey 08903, United States
| | - Hong Wang
- Susan
Lehman Cullman Laboratory for Cancer Research, Department of Chemical
Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Zhi Yun Du
- Allan
H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou 510006, People’s
Republic of China
| | - Dongli Li
- Allan
H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou 510006, People’s
Republic of China
| | - Kun Zhang
- Allan
H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou 510006, People’s
Republic of China
| | - Ah-Ng Tony Kong
- Rutgers
Cancer Institute of New Jersey, New Brunswick, New Jersey 08903, United States
- Department
of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Robert S. DiPaola
- Rutgers
Cancer Institute of New Jersey, New Brunswick, New Jersey 08903, United States
| | - Chung S. Yang
- Susan
Lehman Cullman Laboratory for Cancer Research, Department of Chemical
Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
- Rutgers
Cancer Institute of New Jersey, New Brunswick, New Jersey 08903, United States
| | - Allan
H. Conney
- Susan
Lehman Cullman Laboratory for Cancer Research, Department of Chemical
Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
- Rutgers
Cancer Institute of New Jersey, New Brunswick, New Jersey 08903, United States
| | - Xi Zheng
- Allan
H. Conney Laboratory for Anticancer Research, Guangdong University of Technology, Guangzhou 510006, People’s
Republic of China
- Susan
Lehman Cullman Laboratory for Cancer Research, Department of Chemical
Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
- Phone: 848-445-8069; fax: 732-445-0687; e-mail:
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15
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Wang L, Zhang C, Guo Y, Su ZY, Yang Y, Shu L, Kong ANT. Blocking of JB6 cell transformation by tanshinone IIA: epigenetic reactivation of Nrf2 antioxidative stress pathway. AAPS JOURNAL 2014; 16:1214-25. [PMID: 25274607 DOI: 10.1208/s12248-014-9666-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 09/03/2014] [Indexed: 12/18/2022]
Abstract
Increasing numbers of natural products have been found to possess anticancer effects. Nuclear factor erythroid-2-related factor-2 (Nrf2) is a master regulator of the antioxidative stress response, and our previous studies found that epigenetic modification of the Nrf2 gene appears to be a critical mechanism. Salvia miltiorrhiza, a Chinese herbal medicine widely used in Asian countries, has been shown to possess anticancer and antioxidant effects. Tanshinone IIA (TIIA), an active component in S. miltiorrhiza, has been reported to activate Nrf2 pathway. The objective of this study was to investigate the epigenetic regulation of Nrf2 by TIIA in mouse skin epidermal JB6 cells and the functional consequences for cell transformation. TIIA was found to induce antioxidant response element-luciferase and upregulate the mRNA and protein levels of Nrf2 and Nrf2 downstream target genes HO-1 and NQO-1. TIIA decreased the colony formation of JB6 cells by approximately 80%. TIIA decreased the protein levels of DNMT1, DNMT3a, DNMT3b, and HDAC3 and inhibited the enzymatic activity of HDACs. Bisulfite genomic sequencing indicated that TIIA demethylated the first five CpGs in the promoter region of the Nrf2 gene. Chromatin immunoprecipitation assays showed that TIIA treatment increased the recruitment of RNA polymerase II at Nrf2 transcription start site but had limited effects on enrichment of Ac-H3 in Nrf2 promoter. Taken together, our results show that TIIA activates the Nrf2 signaling pathway and induces epigenetic demethylation of the CpGs of Nrf2. The epigenetic reactivation of the Nrf2 signaling pathway by TIIA could potentially contribute to the attenuation of JB6 cellular transformation and anticancer effects.
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Affiliation(s)
- Ling Wang
- Department of Clinical Pharmacy and Pharmacy Administration, West China School of Pharmacy, Sichuan University, 610041, Chengdu, Sichuan, China,
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16
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Yang CS, Li G, Yang Z, Guan F, Chen A, Ju J. Cancer prevention by tocopherols and tea polyphenols. Cancer Lett 2013; 334:79-85. [PMID: 23403075 DOI: 10.1016/j.canlet.2013.01.051] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 01/28/2013] [Accepted: 01/30/2013] [Indexed: 02/07/2023]
Abstract
Tocopherols (vitamin E) and tea polyphenols have been reported to have cancer preventive activities. Large-scale human trials with high doses of alpha-tocopherol, however, have produced disappointing results. This review presents data showing that - and -tocopherols inhibit colon, lung, mammary and prostate carcinogenesis in animal models, whereas -tocopherol is ineffective in animal and human studies. Possible mechanisms of action are discussed. A broad cancer preventive activity of green tea polyphenols has been demonstrated in animal models, and many mechanisms have been proposed. The cancer preventive activity of green tea in humans, however, has not been conclusively demonstrated and remains to be further investigated.
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Affiliation(s)
- Chung S Yang
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, United States.
| | - Guangxun Li
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
| | - Zhihong Yang
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
| | - Fei Guan
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
| | - Amber Chen
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
| | - Jihyeung Ju
- Department of Food and Nutrition, Chungbuk National University, 52 Naesudong-ro, Heungdeok-gu, Cheongju 361-763, South Korea
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17
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Huang Y, Khor TO, Shu L, Saw CLL, Wu TY, Suh N, Yang CS, Kong ANT. A γ-tocopherol-rich mixture of tocopherols maintains Nrf2 expression in prostate tumors of TRAMP mice via epigenetic inhibition of CpG methylation. J Nutr 2012; 142:818-23. [PMID: 22457388 PMCID: PMC3327740 DOI: 10.3945/jn.111.153114] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Nuclear factor-erythroid 2-related factor 2 (Nrf2) plays a pivotal role in maintaining cellular redox homeostasis and eliminating reactive toxic species. Nrf2 is epigenetically suppressed due to CpG hypermethylation in prostate tumors from the transgenic adenocarcinoma of the mouse prostate (TRAMP) model. We previously showed that dietary feeding of a γ-tocopherol-rich mixture of tocopherols (γ-TmT) suppressed prostate tumorigenesis in TRAMP mice associated with higher Nrf2 protein expression. We hypothesized that γ-TmT may maintain Nrf2 through epigenetic inhibition of promoter CpG methylation. In this study, 8-wk-old male TRAMP mice were fed 0.1% γ-TmT or a control diet for 16 wk. The methylation in the Nrf2 promoter was inhibited in the prostate of the γ-TmT group compared with the control group. Protein expressions of DNA methyltransferase (DNMT), including DNMT1, DNMT3A, and DNMT3B, were lower in the prostate of the γ-TmT group than in the controls. TRAMP-C1 cells were treated with 30 μmol/L of γ-TmT or blank medium for 5 d. The methylation in the Nrf2 promoter was inhibited in the γ-TmT-treated cells compared with the untreated cells at d 5, and mRNA and protein expressions of Nrf2 and NAD(P)H:quinone oxidoreductase 1 were higher. Interestingly, only DNMT3B was inhibited in the γ-TmT-treated cells compared with the untreated cells. In the aggregate, our findings demonstrate that γ-TmT could inhibit CpG methylation in the Nrf2 promoter in the prostate of TRAMP mice and in TRAMP-C1 cells, which might lead to higher Nrf2 expression and potentially contribute to the prevention of prostate tumorigenesis in this TRAMP model.
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Affiliation(s)
| | | | | | | | | | - Nanjoo Suh
- Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Center for Cancer Prevention Research, Earnest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ
| | - Chung S. Yang
- Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Center for Cancer Prevention Research, Earnest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ
| | - Ah-Ng Tony Kong
- Department of Pharmaceutics, and,To whom correspondence should be addressed. E-mail:
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18
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Abstract
The cancer preventive activity of vitamin E has been suggested by many epidemiologic studies. However, several recent large-scale human trials with α-tocopherol, the most commonly recognized and used form of vitamin E, failed to show a cancer preventive effect. The recently finished follow-up of the Selenium and Vitamin E Cancer Prevention Trial (SELECT) even showed higher prostate cancer incidence in subjects who took α-tocopherol supplementation. The scientific community and the general public are faced with a question: "Does vitamin E prevent or promote cancer?" Our recent results in animal models have shown the cancer preventive activity of γ- and δ-tocopherols as well as a naturally occurring mixture of tocopherols, and the lack of cancer preventive activity by α-tocopherol. On the basis of these results as well as information from the literature, we suggest that vitamin E, as ingested in the diet or in supplements that are rich in γ- and δ-tocopherols, is cancer preventive; whereas supplementation with high doses of α-tocopherol is not.
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Affiliation(s)
- Chung S Yang
- Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, 08854, USA.
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19
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Guan F, Li G, Liu AB, Lee MJ, Yang Z, Chen YK, Lin Y, Shih W, Yang CS. δ- and γ-tocopherols, but not α-tocopherol, inhibit colon carcinogenesis in azoxymethane-treated F344 rats. Cancer Prev Res (Phila) 2012; 5:644-54. [PMID: 22366914 DOI: 10.1158/1940-6207.capr-11-0521] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The cancer preventive activity of vitamin E has been extensively discussed, but the activities of specific forms of tocopherols have not received sufficient attention. Herein, we compared the activities of δ-tocopherol (δ-T), γ-T, and α-T in a colon carcinogenesis model. Male F344 rats, seven weeks old, were given two weekly subcutaneous injections of azoxymethane (AOM) each at a dose of 15 mg/kg body weight. Starting 1 week before the AOM injection, the animals were maintained on a modified AIN76A diet, or the same diet containing 0.2% of δ-T, γ-T, α-T, or a γ-T-rich mixture of tocopherols (γ-TmT), until the termination of the experiment at 8 weeks after the second AOM injection. δ-T treatment showed the strongest inhibitory effect, decreasing the numbers of aberrant crypt foci by 62%. γ-T and γ-TmT were also effective, but α-T was not. Immunohistochemical analysis showed that δ-T and γ-T treatments reduced the levels of 4-hydroxynonenal and nitrotyrosine and the expression of cyclin D1 in the colon, preserved the expression of PPAR-γ, and decreased the serum levels of prostaglandin E2 and 8-isoprostane. Supplementation with 0.2% δ-T, γ-T, or α-T increased the respective levels of tocopherols and their side-chain degradation metabolites in the serum and colon tissues. Rather high concentrations of δ-T and γ-T and their metabolites were found in colon tissues. Our study provides the first evidence for the much higher cancer preventive activity of δ-T and γ-T than α-T in a chemically induced colon carcinogenesis model. It further suggests that δ-T is more effective than γ-T.
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Affiliation(s)
- Fei Guan
- Department of Chemical Biology and Center for Cancer Prevention Research, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 164 Frelinghuysen Road, Piscataway, NJ 08854, USA
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20
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Abstract
Many epidemiological studies have suggested that a low vitamin E nutritional status is associated with increased cancer risk. However, several recent large-scale human trials with high doses of α-tocopherol (α-T) have produced disappointing results. This points out the need for a better understanding of the biological activities of the different forms of tocopherols. Using a naturally occurring tocopherol mixture (γ-TmT) that is rich in γ-T, we demonstrated the inhibition of chemically induced lung, colon, and mammary cancer formation as well as the growth of xenograft tumors derived from human lung and prostate cancer cells. This broad anticancer activity of γ-TmT has been attributed mainly to the trapping of reactive oxygen and nitrogen species and inhibition of arachidonic acid metabolism. Activation of peroxisome proliferator-activated receptor γ (PPARγ) and the inhibition of estrogen signaling have also been observed in the inhibition of mammary cancer development. δ-T has been shown to be more active than γ-T in inhibiting the growth of human lung cancer cells in a xenograft tumor model and the development of aberrant crypt foci in azoxymethane-treated rats, whereas α-T is not effective in these models. The higher inhibitory activities of δ-T and γ-T (than α-T) are proposed to be due to their trapping of reactive nitrogen species and their capacity to generate side-chain degradation products, which retain the intact chromanol ring structure and could have cancer preventive activities.
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