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Abdel-Wahab BA, Alqhtani H, Walbi IA, Albarqi HA, Aljadaan AM, Khateeb MM, Hassanein EHM. Piclamilast mitigates 1,2-dimethylhydrazine induced colon cancer in rats through modulation of Ras/PI3K/Akt/mTOR and NF-κβ signaling. Chem Biol Interact 2021; 350:109686. [PMID: 34627785 DOI: 10.1016/j.cbi.2021.109686] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/25/2021] [Accepted: 10/05/2021] [Indexed: 02/07/2023]
Abstract
Colorectal cancer (CRC) is the third leading type of adult cancer in both genders with high morbidity and mortality worldwide. Even though the discovery of many antineoplastic drugs for CRC, the current therapy is not adequately efficient.This study was designed to investigate the effect and mechanism of Piclamilast (PIC), a selective PDE4 inhibitor, on a DMH-induced colorectal cancer (CRC) rat model. The rats were grouped (n = 10) into group 1 (control), group 2 (PIC 3 mg/kg, p.o.), groups 3-5 received DMH (20 mg/kg/week, S.C.), and groups 4 and 5 received PIC (1 and 3 mg/kg/day, p.o.) for 15 weeks. The DMH treatment increased aberrant crypt foci (ACF), Proliferating cell nuclear antigen (PCNA), and TBARS levels, along with decreased antioxidant defenses (GSH, GSH-Px, and catalase). Increased NF-κβ expression and inflammatory cytokines were also evident. PIC dose-dependently reduced ACF and restored oxidative stress and inflammatory markers favorably. Moreover, PIC in its large, tested dose only significantly increased the intracellular level of cAMP and suppressed the activation of Ras and PI3K and its downstream Akt/mTOR signaling. Furthermore, PIC promoted CRC apoptosis, and increased the gene expression of the apoptotic factors, caspase-3 and Bax, and decreased the anti-apoptotic factor Bcl-2. The results of this study show that PIC may be a promising therapeutic agent for the treatment of CRC. PIC might inhibit the proliferation of CRC cells and induce apoptosis via multiple mechanisms that involve its antioxidant effect and inhibition of NF-κβ and Ras/PI3K/Akt/mTOR signaling.
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Affiliation(s)
- Basel A Abdel-Wahab
- Department of Pharmacology, College of Pharmacy, Najran University, Kingdom of Saudi Arabia; Department of Medical Pharmacology, College of Medicine, Assiut University, Assiut, Egypt.
| | - Hussain Alqhtani
- Department of Clinical Pharmacy, College of Pharmacy, Najran University, Kingdom of Saudi Arabia
| | - Ismail A Walbi
- Department of Clinical Pharmacy, College of Pharmacy, Najran University, Kingdom of Saudi Arabia
| | - Hassan A Albarqi
- Department of Pharmaceutics, College of Pharmacy, Najran University, Kingdom of Saudi Arabia
| | - Adel M Aljadaan
- Department of Pharmacology, College of Pharmacy, Najran University, Kingdom of Saudi Arabia; School of Medicine, University of Nottingham, United Kingdom
| | - Masood M Khateeb
- Department of Pharmacology, College of Pharmacy, Najran University, Kingdom of Saudi Arabia
| | - Emad H M Hassanein
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Al-Azhar University, Assiut Branch, Egypt
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Potential Role of Curcumin and Its Nanoformulations to Treat Various Types of Cancers. Biomolecules 2021; 11:biom11030392. [PMID: 33800000 PMCID: PMC8001478 DOI: 10.3390/biom11030392] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/27/2021] [Accepted: 03/03/2021] [Indexed: 12/17/2022] Open
Abstract
Cancer is a major burden of disease globally. Each year, tens of millions of people are diagnosed with cancer worldwide, and more than half of the patients eventually die from it. Significant advances have been noticed in cancer treatment, but the mortality and incidence rates of cancers are still high. Thus, there is a growing research interest in developing more effective and less toxic cancer treatment approaches. Curcumin (CUR), the major active component of turmeric (Curcuma longa L.), has gained great research interest as an antioxidant, anticancer, and anti-inflammatory agent. This natural compound shows its anticancer effect through several pathways including interfering with multiple cellular mechanisms and inhibiting/inducing the generation of multiple cytokines, enzymes, or growth factors including IκB kinase β (IκKβ), tumor necrosis factor-alpha (TNF-α), signal transducer, and activator of transcription 3 (STAT3), cyclooxygenase II (COX-2), protein kinase D1 (PKD1), nuclear factor-kappa B (NF-κB), epidermal growth factor, and mitogen-activated protein kinase (MAPK). Interestingly, the anticancer activity of CUR has been limited primarily due to its poor water solubility, which can lead to low chemical stability, low oral bioavailability, and low cellular uptake. Delivering drugs at a controlled rate, slow delivery, and targeted delivery are other very attractive methods and have been pursued vigorously. Multiple CUR nanoformulations have also been developed so far to ameliorate solubility and bioavailability of CUR and to provide protection to CUR against hydrolysis inactivation. In this review, we have summarized the anticancer activity of CUR against several cancers, for example, gastrointestinal, head and neck, brain, pancreatic, colorectal, breast, and prostate cancers. In addition, we have also focused on the findings obtained from multiple experimental and clinical studies regarding the anticancer effect of CUR in animal models, human subjects, and cancer cell lines.
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Nouri Z, Fakhri S, Nouri K, Wallace CE, Farzaei MH, Bishayee A. Targeting Multiple Signaling Pathways in Cancer: The Rutin Therapeutic Approach. Cancers (Basel) 2020; 12:E2276. [PMID: 32823876 PMCID: PMC7463935 DOI: 10.3390/cancers12082276] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/07/2020] [Accepted: 08/10/2020] [Indexed: 12/21/2022] Open
Abstract
Multiple dysregulated signaling pathways are implicated in the pathogenesis of cancer. The conventional therapies used in cancer prevention/treatment suffer from low efficacy, considerable toxicity, and high cost. Hence, the discovery and development of novel multi-targeted agents to attenuate the dysregulated signaling in cancer is of great importance. In recent decades, phytochemicals from dietary and medicinal plants have been successfully introduced as alternative anticancer agents due to their ability to modulate numerous oncogenic and oncosuppressive signaling pathways. Rutin (also known as rutoside, quercetin-3-O-rutinoside and sophorin) is an active plant-derived flavonoid that is widely distributed in various vegetables, fruits, and medicinal plants, including asparagus, buckwheat, apricots, apples, cherries, grapes, grapefruit, plums, oranges, and tea. Rutin has been shown to target various inflammatory, apoptotic, autophagic, and angiogenic signaling mediators, including nuclear factor-κB, tumor necrosis factor-α, interleukins, light chain 3/Beclin, B cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein, caspases, and vascular endothelial growth factor. A comprehensive and critical analysis of the anticancer potential of rutin and associated molecular targets amongst various cancer types has not been performed previously. Accordingly, the purpose of this review is to present an up-to-date and critical evaluation of multiple cellular and molecular mechanisms through which the anticancer effects of rutin are known to be exerted. The current challenges and limitations as well as future directions of research are also discussed.
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Affiliation(s)
- Zeinab Nouri
- Student Research Committee, Faculty of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah 6714415153, Iran;
| | - Sajad Fakhri
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah 6734667149, Iran;
| | - Keyvan Nouri
- Student Research Committee, School of Medicine, Isfahan University of Medical Sciences, Isfahan 8174673461, Iran;
| | - Carly E. Wallace
- Lake Erie College of Osteopathic Medicine, Bradenton, FL 34211, USA;
| | - Mohammad Hosein Farzaei
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah 6734667149, Iran;
| | - Anupam Bishayee
- Lake Erie College of Osteopathic Medicine, Bradenton, FL 34211, USA;
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Braakhuis HM, Gosens I, Heringa MB, Oomen AG, Vandebriel RJ, Groenewold M, Cassee FR. Mechanism of Action of TiO 2: Recommendations to Reduce Uncertainties Related to Carcinogenic Potential. Annu Rev Pharmacol Toxicol 2020; 61:203-223. [PMID: 32284010 DOI: 10.1146/annurev-pharmtox-101419-100049] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Risk Assessment Committee of the European Chemicals Agency issued an opinion on classifying titanium dioxide (TiO2) as a suspected human carcinogen upon inhalation. Recent animal studies indicate that TiO2 may be carcinogenic through the oral route. There is considerable uncertainty on the carcinogenicity of TiO2, which may be decreased if its mechanism of action becomes clearer. Here we consider adverse outcome pathways and present the available information on each of the key events (KEs). Inhalation exposure to TiO2 can induce lung tumors in rats via a mechanism that is also applicable to other poorly soluble, low-toxicity particles. To reduce uncertainties regarding human relevance, we recommend gathering information on earlier KEs such as oxidative stress in humans. For oral exposure, insufficient information is available to conclude whether TiO2 can induce intestinal tumors. An oral carcinogenicity study with well-characterized (food-grade) TiO2 is needed, including an assessment of toxicokinetics and early KEs.
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Affiliation(s)
- Hedwig M Braakhuis
- National Institute for Public Health and the Environment (RIVM), 3720 BA Bilthoven, The Netherlands;
| | - Ilse Gosens
- National Institute for Public Health and the Environment (RIVM), 3720 BA Bilthoven, The Netherlands;
| | - Minne B Heringa
- National Institute for Public Health and the Environment (RIVM), 3720 BA Bilthoven, The Netherlands; .,Current affiliation: Reckitt Benckiser, 1118 BH Schiphol, The Netherlands
| | - Agnes G Oomen
- National Institute for Public Health and the Environment (RIVM), 3720 BA Bilthoven, The Netherlands;
| | - Rob J Vandebriel
- National Institute for Public Health and the Environment (RIVM), 3720 BA Bilthoven, The Netherlands;
| | - Monique Groenewold
- National Institute for Public Health and the Environment (RIVM), 3720 BA Bilthoven, The Netherlands;
| | - Flemming R Cassee
- National Institute for Public Health and the Environment (RIVM), 3720 BA Bilthoven, The Netherlands; .,Institute for Risk Assessment Sciences, University of Utrecht, 3508 TD Utrecht, The Netherlands
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Younes M, Aggett P, Aguilar F, Crebelli R, Dusemund B, Filipič M, Frutos MJ, Galtier P, Gott D, Gundert‐Remy U, Kuhnle GG, Lambré C, Leblanc J, Lillegaard IT, Moldeus P, Mortensen A, Oskarsson A, Stankovic I, Waalkens‐Berendsen I, Wright M, Lodi F, Rincon AM, Smeraldi C, Woutersen RA. Evaluation of four new studies on the potential toxicity of titanium dioxide used as a food additive (E 171). EFSA J 2018; 16:e05366. [PMID: 32625996 PMCID: PMC7009373 DOI: 10.2903/j.efsa.2018.5366] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The European Commission requested EFSA to carry out a scientific evaluation on four studies on the potential toxicity of titanium dioxide (TiO2) used as a food additive (E 171) and to indicate whether they would merit re‐opening the existing opinion of EFSA on the safety of TiO2 (E 171) as a food additive. The results of the Bettini et al. (2017) study did not provide enough justification for a new carcinogenicity study, but, should additional useful mechanistic information become available, this could be reconsidered in future. The new in vitro findings in the Proquin et al. (2017) study did not modify the conclusion on the genotoxicity of TiO2 as stated in the previous EFSA opinion of 2016 on the safety of TiO2 (E 171) as a food additive. The effects of engineered TiO2 nanoparticles reported by the Guo et al. (2017) study were of uncertain biological significance and therefore of limited relevance for the risk assessment of the food additive TiO2 (E 171). There was significant uncertainty in the risk assessment performed by Heringa et al. (2016), which did not include a weight of evidence analysis of the whole database. The Panel considered that the four studies evaluated, highlighted some concerns but with uncertainties, therefore their relevance for the risk assessment was considered limited and further research would be needed to decrease the level of uncertainties. Overall, three of the studies, reporting that TiO2 induced various effects in in vitro and in vivo models, may be useful for hazard identification of TiO2. In the fourth study by Heringa et al. (2016), numerous assumptions were made, which resulted in large uncertainty in their conclusion. Altogether, the Panel concluded that the outcome of the four studies did not merit re‐opening the existing opinion of EFSA related to the safety of TiO2 (E 171) as a food additive.
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Rajasekaran SA. Therapeutic potential of curcumin in gastrointestinal diseases. World J Gastrointest Pathophysiol 2011; 2:1-14. [PMID: 21607160 PMCID: PMC3097964 DOI: 10.4291/wjgp.v2.i1.1] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 11/25/2010] [Accepted: 12/02/2010] [Indexed: 02/06/2023] Open
Abstract
Curcumin, also known as diferuloylmethane, is derived from the plant Curcuma longa and is the active ingredient of the spice turmeric. The therapeutic activities of curcumin for a wide variety of diseases such as diabetes, allergies, arthritis and other chronic and inflammatory diseases have been known for a long time. More recently, curcumin’s therapeutic potential for preventing and treating various cancers is being recognized. As curcumin’s therapeutic promise is being explored more systematically in various diseases, it has become clear that, due to its increased bioavailability in the gastrointestinal tract, curcumin may be particularly suited to be developed to treat gastrointestinal diseases. This review summarizes some of the current literature of curcumin’s anti-inflammatory, anti-oxidant and anti-cancer potential in inflammatory bowel diseases, hepatic fibrosis and gastrointestinal cancers.
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Xu G, Ren G, Xu X, Yuan H, Wang Z, Kang L, Yu W, Tian K. Combination of curcumin and green tea catechins prevents dimethylhydrazine-induced colon carcinogenesis. Food Chem Toxicol 2009; 48:390-5. [PMID: 19861145 DOI: 10.1016/j.fct.2009.10.027] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 10/19/2009] [Accepted: 10/21/2009] [Indexed: 02/07/2023]
Abstract
The chemopreventive effects of curcumin and green tea catechins individually and in combination on 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis were studied in male Wister rats following 32 weeks of dietary treatment. The incidence, number and size of colorectal cancer were measured. Colorectal aberrant crypt foci (ACF) were analyzed by methylene blue staining. Proliferation indices and apoptotic indices were determined by PCNA immunostaining and TUNEL assay, respectively. The results showed that dietary curcumin, catechins and combination administration significantly inhibited the total number of ACF per rat. The combination treatment displayed the most potent inhibitory effect, while there was no difference of inhibition between curcumin and catechins-treated groups. The incidence of colorectal cancer in the treated groups was significantly lower than that of positive control group. Compared with the positive control group, the proliferation index was significantly decreased and the apoptotic index was significantly increased in all treatment groups, while the effect of the combination was the greatest among the treated groups. Our findings suggest that the combination of curcumin and catechins may produce a synergistic colon cancer-preventative effect that would be more potent than each of the compounds alone.
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Affiliation(s)
- Gang Xu
- Department of Gastroenterology, 456 Hospital of PLA, 25 Wuyingshan Road, Jinan 250031, Shandong, China
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van Beelen VA, Spenkelink B, Mooibroek H, Sijtsma L, Bosch D, Rietjens IM, Alink GM. An n-3 PUFA-rich microalgal oil diet protects to a similar extent as a fish oil-rich diet against AOM-induced colonic aberrant crypt foci in F344 rats. Food Chem Toxicol 2009; 47:316-20. [DOI: 10.1016/j.fct.2008.11.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 10/11/2008] [Accepted: 11/11/2008] [Indexed: 11/16/2022]
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Anand P, Sundaram C, Jhurani S, Kunnumakkara AB, Aggarwal BB. Curcumin and cancer: An “old-age” disease with an “age-old” solution. Cancer Lett 2008; 267:133-64. [DOI: 10.1016/j.canlet.2008.03.025] [Citation(s) in RCA: 651] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 03/11/2008] [Accepted: 03/12/2008] [Indexed: 02/07/2023]
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10
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Dihal AA, de Boer VCJ, van der Woude H, Tilburgs C, Bruijntjes JP, Alink GM, Rietjens IMCM, Woutersen RA, Stierum RH. Quercetin, but not its glycosidated conjugate rutin, inhibits azoxymethane-induced colorectal carcinogenesis in F344 rats. J Nutr 2006; 136:2862-7. [PMID: 17056814 DOI: 10.1093/jn/136.11.2862] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The effect of the flavonoid quercetin and its conjugate rutin was investigated on (biomarkers of) colorectal cancer (CRC). Male F344 rats (n = 42/group) were fed 0, 0.1, 1, or 10 g quercetin/kg diet or 40 g rutin/kg diet. Two wk after initial administration of experimental diets, rats were given 2 weekly subcutaneous injections with 15 mg/kg body wt azoxymethane (AOM). At wk 38 post-AOM, quercetin dose dependently (P < 0.05) decreased the tumor incidence, multiplicity, and size, whereas tumor incidences were comparable in control (50%) and rutin (45%) groups. The number of aberrant crypt foci (ACF) in unsectioned colons at wk 8 did not correlate with the tumor incidence at wk 38. Moreover, at wk 8 post-AOM, the number and multiplicity of ACF with or without accumulation of beta-catenin were not affected by the 10 g quercetin/kg diet. In contrast, another class of CRC-biomarkers, beta-catenin accumulated crypts, contained less beta-catenin than in controls (P < 0.05). After enzymatic deconjugation, the plasma concentration of 3'-O-methyl-quercetin and quercetin at wk 8 was inversely correlated with the tumor incidence at wk 38 (r = -0.95, P </= 0.05). Rats supplemented with 40 g rutin/kg diet had only 30% of the (3'-O-methyl-) quercetin concentration of 10 g quercetin/kg diet-fed rats (P < 0.001). In conclusion, quercetin, but not rutin, at a high dose reduced colorectal carcinogenesis in AOM-treated rats, which was not reflected by changes in ACF-parameters. The lack of protection by rutin is probably due to its low bioavailability.
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Affiliation(s)
- Ashwin A Dihal
- TNO Quality of Life, Business Unit Biosciences, Zeist, The Netherlands.
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11
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Dias MC, Spinardi-Barbisan ALT, Rodrigues MAM, de Camargo JLV, Terán E, Barbisan LF. Lack of chemopreventive effects of ginger on colon carcinogenesis induced by 1,2-dimethylhydrazine in rats. Food Chem Toxicol 2006; 44:877-84. [PMID: 16442687 DOI: 10.1016/j.fct.2005.11.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Revised: 11/10/2005] [Accepted: 11/23/2005] [Indexed: 10/25/2022]
Abstract
Ginger (Zingiber officinale Roscoe) has been proposed as a promising candidate for cancer prevention. Its modifying potential on the process of colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) was investigated in male Wistar rats using the aberrant crypt foci (ACF) assay. Five groups were studied: Groups 1-3 were given four s.c. injections of DMH (40 mg/kg b.w.) twice a week, during two weeks, whereas Groups 4 and 5 received similar injections of EDTA solution (DMH vehicle). After DMH-initiation, the animals were fed a ginger extract mixed in the basal diet at 0.5% (Group 2) and 1.0% (Groups 3 and 4) for 10 weeks. All rats were killed after 12 weeks and the colons were analyzed for ACF formation and crypt multiplicity. The rates of cell proliferation and apoptosis were also evaluated in epithelial colonic crypt cells. Dietary consumption of ginger at both dose levels did not induce any toxicity in the rats, but ginger meal at 1% decreased significantly serum cholesterol levels (p<0.038). Treatment with ginger did not suppress ACF formation or the number of crypts per ACF in the DMH-treated group. Dietary ginger did not significantly change the proliferative or apoptosis indexes of the colonic crypt cells induced by DMH. Thus, the present results did not confirm a chemopreventive activity of ginger on colon carcinogenesis as analyzed by the ACF bioassay and by the growth kinetics of the colonic mucosa.
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Affiliation(s)
- M C Dias
- UNESP São Paulo State University, Institute of Biosciences, Department of Morphology, Botucatu 18618-000, SP, Brazil
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Ross SA, Finley JW, Milner JA. Allyl sulfur compounds from garlic modulate aberrant crypt formation. J Nutr 2006; 136:852S-854S. [PMID: 16484579 DOI: 10.1093/jn/136.3.852s] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The health benefits of garlic, including inhibition of carcinogenesis, are supported by several epidemiologic and laboratory findings. Garlic's sulfur components have been reported to suppress experimentally induced tumor incidence in several organs, including the colon. Studies in humans also suggest that dietary garlic constituents reduce the risk of colorectal adenomatous polyps, which are considered precursors to colon cancer. Aberrant crypt foci (ACF) are proposed to be early preneoplastic lesions of adenoma-carcinoma in humans and chemically induced colon cancer in rodents. In preclinical studies, both water- and lipid-soluble allyl sulfur compounds arising from processed garlic inhibited ACF. The response to these allyl sulfur compounds appears to depend on several factors, including the speciation, quantity, and duration provided.
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Affiliation(s)
- Sharon A Ross
- Nutritional Sciences Research Group, Division of Cancer Prevention, National Cancer Institute, National Institutes of Health, U S Department of Health and Human Services, Rockville, MD 20892-7328, USA.
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Corpet DE, Pierre F. How good are rodent models of carcinogenesis in predicting efficacy in humans? A systematic review and meta-analysis of colon chemoprevention in rats, mice and men. Eur J Cancer 2005; 41:1911-22. [PMID: 16084718 DOI: 10.1016/j.ejca.2005.06.006] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Revised: 06/13/2005] [Accepted: 06/15/2005] [Indexed: 12/17/2022]
Abstract
Tumours in rodent and human colon share many histological and genetic features. To know if rodent models of colon carcinogenesis are good predictors of chemopreventive efficacy in humans, we conducted a meta-analysis of aspirin, beta-carotene, calcium, and wheat bran studies. Controlled intervention studies of adenoma recurrence in human volunteers were compared with chemoprevention studies of carcinogen-induced tumours in rats, and of polyps in Min (Apc(+/-)) mice: 6714 volunteers, 3911 rats and 458 mice were included in the meta-analyses. Difference between models was small since most global relative risks were between 0.76 and 1.00. A closer look showed that carcinogen-induced rat studies matched human trials for aspirin, calcium, carotene, and were compatible for wheat bran. Min mice results were compatible with human results for aspirin, but discordant for calcium and wheat bran (no carotene study). These few results suggest that rodent models roughly predict effect in humans, but the prediction is not accurate for all agents. Based on three cases only, the carcinogen-induced rat model seems better than the Min mouse model. However, rodent studies are useful to screen potential chemopreventive agents, and to study mechanisms of carcinogenesis and chemoprevention.
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Affiliation(s)
- Denis E Corpet
- UMR Xenobiotiques, Institut National Recherche Agronomique, Ecole Nationale Veterinaire Toulouse, BP-87614, 23 Capelles, 31076 Toulouse, France.
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Lim CC, Ferguson LR, Tannock GW. Dietary fibres as "prebiotics": implications for colorectal cancer. Mol Nutr Food Res 2005; 49:609-19. [PMID: 15864790 DOI: 10.1002/mnfr.200500015] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A "prebiotic" is a nondigestible food ingredient whose beneficial effects on the host result from the selective stimulation of growth and/or activity of members of the bacterial community that inhabits the human bowel (the gut microbiota). Although much of the prebiotic literature focuses on nondigestible oligosaccharides, such as oligofructose, most dietary fibres that are fermentable carbohydrates could be considered as prebiotics. Early studies suggested that colonic bacteria were risk factors for colon cancer. However, altering the composition or metabolic activity of the bowel microbiota through the use of dietary fibre might be important in reducing the prevalence of colorectal cancer. Mechanisms for beneficial effects of prebiotics might include changing the activity of exogenous carcinogens through modulating metabolic activation and/or detoxification, or stimulating the production of the short-chain fatty acid, butyrate. However, modern analytical techniques suggest that an important consequence of a modified bacterial community could be a change in the expression not only of a range of different bacterial genes in bowel contents, but also in the bowel mucosa of the host. Analogous with observations with probiotics, the stimulation of cytokines and modification of immune responses could be important in producing beneficial effects. Compared with transitory effects of probiotics, the prebiotic action of fermentable carbohydrates potentially provide the opportunity for sustainable modulation of activity of the gut microbiota. However, their mechanisms of action in humans are speculative, and research aimed at providing an integrated view of the gut microbiota and dietary fibre nutrition of humans needs to be developed.
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Affiliation(s)
- Chiara C Lim
- Discipline of Nutrition, Faculty of Medicine and Health Sciences, The University of Auckland, Auckland, New Zealand
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Current Awareness on Comparative and Functional Genomics. Comp Funct Genomics 2005. [PMCID: PMC2448604 DOI: 10.1002/cfg.419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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