Prevention Of Colon Carcinogenesis Research Articles

Oral Administration of Carotenoid-Rich Dunaliella salina Powder Inhibits Colon Carcinogenesis via Modulation of Wnt/β-catenin Signaling Cascades in a Rat Model.

The present study aims to investigate the oral therapeutic and molecular role of carotenoid-rich Dunaliella salina powder (DSP) against 1,2-dimethylhydrazine (DMH)-triggered colon carcinogenesis. In this study, thirty six male Wistar rats were categorized into six distinct groups (G1-G6): G1 group with no intervention, G2 group received only DSP (1000mg/kg), G3 group received only DMH carcinogen (20mg/kg), and G4-G6 group received both DMH and DSP at various phases (pre-initiation, post-initiation and entire phases) for 32weeks. Body weight, tumor incidence, tumor volume, histopathological examination, antioxidants, and detoxification enzymes activities were analyzed in the experimental rats. In addition, the protein expression profile of components involved in the Wnt/β-catenin signaling pathway was determined by western blot analysis. Matrix metalloproteinases (MMP-7 and MMP-9), proliferation marker (PCNA), and pro-apoptotic (Bcl-2 and Bax) proteins were analyzed using immunohistochemistry. Colorimetric assay was used to determine the levels of anti-inflammatory (iNOS and COX-2) and apoptotic proteins (Caspase-3 and Caspase-9). Results showed that concomitant administration of DSP with DMH significantly reduced tumor progression and prevented colon carcinogenesis in rats. However, treatment with DSP before or after DMH exposure did not significantly prevent colon carcinogenesis. DMH and DSP treatment group showed increased activities of antioxidant enzymes with significant reduction in the oxidative stress. Additionally, the detoxification enzymes and colonic histopathology of those rats were restored to that of control rats. The administration of DSP to rats exposed to DMH exhibited antitumor effects via inhibition of the Wnt/β-catenin signaling pathway with induced apoptosis through the Bcl-2/Bax/caspases signaling cascades. Moreover, the same group also showed significant anti-inflammatory activity via regulating iNOS and COX-2 biomarkers. Our findings revealed molecular chemopreventive activity of carotenoid-rich DSP through regulating Wnt/beta-catenin and intrinsic apoptotic pathways. Thus, DSP is propound to function as a potent antioxidant, anti-proliferative, and anti-inflammatory therapeutic agent against colon carcinogenesis.

Abstract 5635: TPM4 overexpression promotes colon epithelial cell tumorigenesis in vitro and correlates with human colon tumor progression in vivo

Abstract Because colon cancer still exerts a heavy burden on human health, we are interested in identifying very early events in colon epithelial cell tumorigenesis in order to develop strategies to treat and possibly prevent colon carcinogenesis. We hypothesize that aberrant expression of genes involved in crypt-luminal colon epithelial cell migration, needed for proliferative, undifferentiated stem cells at the crypt bottom to mature into growth arrested, mature effector cells near the lumen, may disrupt normal differentiation and initiate events that can trigger the transition from a normal to premalignant state in colon epithelial cells. Forced upregulation of tropomyosin 4 (TPM4), an actin-binding protein that exerts many effects on contractility and migration, prevents certain aspects of Caco2 maturation induced by contact inhibition of growth, including increased expression of the digestive enzyme sucrose isomaltase and glutathione S-transferase alpha 1. Furthermore, TPM4.2-overexpressing cells exhibit numerous morphological abnormalities. Compared to untransfected Caco2 cells and empty-vector stable transfectant controls, TPM4.2-overexpressing Caco2 cell clones elaborate aberrant thin membrane protrusions and expanded membrane ruffles. Particularly striking are defective maintenance of dome structures at middle (day 14) and late (day 21) time points of induced differentiation in TPM4.2-overeexpressing clones. We further hypothesize that TPM4 is overexpressed in human colon tumors, particularly at early stages of tumorigenesis. In order to test this hypothesis, we examined TPM4 RNA expression in datasets obtained from human colon tissue at premalignant as well as tumorigenic stages. TPM4 trends toward overexpression in premalignant, relative to normal, human colon tissue (uninvolved mucosa from patients with familial adenomatous polyposis, or FAP) and is significantly overexpressed in adenocarcinoma tissue relative to normal controls. Interestingly, TPM4 overexpression may be more pronounced at earlier, rather than later, stages of adenocarcinoma. Our results suggest that aberrant TPM4 overexpression in colon epithelial cells can promote adoption of a tumorigenic state. Certain aspects of Caco2 cell maturation are disrupted by forced TPM4 overexpression during induced differentiation, and TPM4 overexpression correlates with early stages of colon tumorigenesis. Misregulation of TPM4 gene expression may therefore represent a critical molecular event that can block normal differentiation and induce early events in colon epithelial cell tumorigenesis. TPM4 expression level may therefore prove to be a useful biomarker that can, along with other diagnostics, help to determine tumorigenic progression in human colon tissue and to develop novel strategies to prevent colon cancer and treat it at early stages. Citation Format: Giulio Ferrero, Barbara Pardini, Alessio Naccarati, Michael Papetti. TPM4 overexpression promotes colon epithelial cell tumorigenesis in vitro and correlates with human colon tumor progression in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5635.

Protective benefits of ethyl alcohol extract of Piper betel L. to prevent colon carcinogenesis

Piper betel L. is a traditional nutritional and medicinal food, known for its rich phytochemical components. In the current study, the role of the ethyl alcohol extract of betel leaf (Piper betel) against human colorectal carcinoma (HT29 cells), was investigated. The extract consists of phenolic compounds and flavonoids that are potent antioxidants and antimicrobial agents. Exposure of human colon carcinoma cells, to the 80% ethyl alcohol extract resulted in apoptotic cell death, fragmentation, downregulation in the expression levels of Bcl-XL, and upregulation of p53. The results indicated the inhibition of cell proliferation in a dose-dependent manner. The results highlight the activation of the mitochondrial apoptotic pathway in response to the treatment with ethanolic extracts of betel leaves. The treatment induced DNA damage leading to G1 cell cycle arrest and apoptosis. Low cytotoxicity and anticarcinogenic effects of the ethyl alcohol extracts of betel leaf on HT29 suggest an alternative approach to human colon cancer therapy (combination therapy) and highlights its significance as a functional food or food supplement.

Effects of aspirin on colon cancer using quantitative proteomic analysis

BackgroundColon cancer is one of the most prevalent digestive cancers worldwide. Results of epidemiological, experimental, and clinical studies suggest that aspirin inhibits the development of colon cancer. This study aimed to systematically elucidate the molecular mechanisms by which aspirin prevents colon carcinogenesis. MethodsWe determined the global protein expression profiles of colorectal cancer and aspirin-treated cells using quantitative proteomic analysis. We analyzed the proteomic results using bioinformatics (including differential proteins, protein annotation, Kyoto Encyclopedia of Genes and Genomes [KEGG] pathways, and protein–protein interaction [PPI] network). The viability of the colon cancer cell line and HT29 ​cells treated with aspirin was determined using the cell counting kit-8 assay. The differentially expressed proteins, such as p53 and cyclin-dependent kinase 1 (CDK1), were quantified using real-time polymerase chain reaction (PCR) and Western blotting. We measured cell cycle distribution and apoptosis in HT29 ​cells exposed to aspirin using fluorescence-activated cell sorting (FACS). ResultsWe found that 552 proteins were significantly dysregulated, of which 208 and 334 were upregulated and downregulated, respectively, in colon cancer cells exposed to 10 ​mmol/L of aspirin (95% confidence interval [CI]: -1.269 to -0.106, P ​< ​0.05). Further gene enrichment analysis revealed that cell cycle-related proteins, such as p53 and CDK1, were significantly differentially expressed. Proteomic analysis showed that after 24 ​h of aspirin exposure, the level of p53 increased by 2.52-fold and CDK1 was downregulated to half that of the controls in HT29 ​cells (95% CI: -0.619 to -0.364, P ​< ​0.05). Real-time PCR and Western blotting results showed that p53 was upregulated (95%CI: -3.088 to -1.912, P ​< ​0.001) and CDK1 was significantly downregulated after aspirin exposure in colon cancer cells (95% CI: 0.576 to 1.045, P ​< ​0.05). We observed that aspirin promoted G1/S cell cycle arrest in HT29 ​cells. We confirmed that aspirin induces apoptosis in human HT29 colon cancer cells in a concentration-dependent manner. ConclusionsThese results indicate that aspirin induces G1 arrest and apoptosis in colorectal cancer cells via the p53–CDK1 pathway. Aspirin may be a promising drug candidate for colon cancer prevention.

Abstract 2978: Cyclic GMP-independent inhibition of colon cancer cell growth by phosphodiesterase inhibitors

Abstract There is growing interest in the potential use of phosphodiesterase (PDE) inhibitors for colon cancer chemoprevention, but the tumor suppressive mechanism is not understood. The present study has tested the idea that PDE inhibitors can suppress growth and promote apoptosis of colon cancer cell lines by increasing cGMP and activating cGMP-dependent protein kinase (PKG). Treatment of LS174T, Caco2, and HCT116 colon cancer cells with membrane permeable 8Br-cGMP had no effect on cell proliferation or viability. Endogenous PKG was undetectable in any of these cells using phosphorylation of the PKG substrate vasodilator-stimulated phosphoprotein (VASP) as a readout. Ectopic expression of PKG2 conferred modest inhibition of proliferation by cGMP treatment (15-25% over 3 days), but did not affect cell viability. The lack of effect of cGMP on colon cancer proliferation is incongruous with many reported effects of PDE inhibitors. To understand the reason for the discrepant observations, colon cancer cells were treated with sildenafil, PF-0447943, and TAK-063 that are specific inhibitors of the cGMP-targeting PDE5, 9, 10a (respectively). At clinically unachievable concentrations exceeding 10μM, all of these drugs reduced proliferation to various degrees in the different cell lines. TAK-063 was the most effective, and the only one that reduced cell viability. Notably, growth-inhibition by the PDE inhibitors was independent of PKG expression, and surprisingly, none of them increased cGMP levels. The inability of the PDE inhibitors to increase cGMP was due to the lack of endogenous cGMP generation, because treatment with the guanylyl-cyclase C agonist linaclotide conferred a robust cGMP response to a physiological dose of sildenafil (1µM). The growth inhibitor effects of high, non-physiological levels of PDE inhibitors is likely due to off-target effects, but apart from a transient inhibition of the ERK pathway, no common mechanism was identified. Taken together, these results refute the idea that cGMP elevating agents prevent colon carcinogenesis by inhibiting cancer cell growth, and support the inhibition of tumor initiation as a more likely mechanism. Citation Format: Bianca N. Islam, Yali Hou, Namratha Mylarapu, Kaylin A. Browning, Kenneth J. Vega, Darren D. Browning. Cyclic GMP-independent inhibition of colon cancer cell growth by phosphodiesterase inhibitors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2978.

β-Glucuronidase inhibitors from Malaysian plants

Toxic metabolites that could promote the formation of tumors are generated with high levels of β-glucuronidase activities. Hence, the inhibition of the β-glucuronidase enzyme is effective in the prevention of colonic carcinogenesis, and other diseases. This study aims to investigate the β-glucuronidase inhibitory effect of compounds that were isolated from Nauclea subdita (Korth.) Steud. and Alpinia pahangensis Ridley, together with their mode of inhibition, and their interactions with the enzyme. Angustine (1) and (E)-labda-8 (17),12-dien-15,16-dial (2) are secondary metabolites which were isolated from Nauclea subdita (Korth.) Steud. and Alpinia pahangensis Ridley, respectively. Both exhibited potent inhibitory activities against the β-glucuronidase enzyme with IC50 values of 5.6 ± 0.70 and 23.61 ± 3.32 μM, respectively. The enzyme kinetic studies suggested that compounds 1 and 2 were non-competitive inhibitors with inhibition constants (Ki) of 8.46 and 22.0 μM, respectively. In silico molecular docking and molecular dynamics simulation studies showed that the amino acid residues that interacted with compounds 1 and 2 were Phe161, Leu361, Phe448, Tyr468, Tyr472, and Leu561. These amino acid residues interacted with compound 1 with lower energy as compared to compound 2. Furthermore, the binding free energy of compound 1 (GBTOT value of −31.69 kcal mol−1) was found to be lower than that of compound 2 (GBTOT value of −22.32 kcal mol−1). Compound 1 was thus predicted to be a more active inhibitor through in silico molecular docking and molecular dynamics simulation studies.

Chemopreventive role of olive oil in colon carcinogenesis by targeting noncoding RNAs and methylation machinery.

Epigenetic therapy induced by dietary components has become a strong interest in the field of cancer prevention. Olive oil, a potent dietary chemopreventive agent, control colon cancer, however, its role in epigenetic therapy remains unclear. Thus, we aimed to investigate the effect of olive oil in a preclinical model of colon cancer by targeting genetic and epigenetic mechanisms. DMH was used to induce colon cancer in rats; while olive oil was given to separate group of rats along with DMH treatment. Tumor burden and incidence in DMH and DMH + olive oil-treated rats was observed by macroscopic examination and histoarchitectural studies. Potent anti-inflammatory, anti-angiogenic and pro-apoptotic activity of olive oil was explored by gene expression and immunohistochemical studies. The effect of olive oil on epigenetic alterations was examined by detecting promoter methylation with MS-HRM and dysregulation of miRNA by TaqMan MicroRNA Assay. We observed that olive oil administration lowered tumor incidence and inhibited the development of tumors in DMH-treated rats. Olive oil markedly decreased the expression of inflammatory and angiogenic markers and restored the expression of pro-apoptotic markers in DMH-treated rats. Furthermore, the inverse relationship between gene expression and DNA methylation, deviant miRNA pattern and miRNA silencing mediated by aberrant DNA methylation was also seen in DMH-treated rats, which was potentially reversible upon olive oil treatment. Our study concludes that olive oil may play a role in the epigenetic therapy by altering NF-κB and apoptotic pathways via targeting noncoding RNAs and methylation machinery that affecting epigenome to prevent colon carcinogenesis.

The chemopreventive effect of withaferin A on spontaneous and inflammation-associated colon carcinogenesis models.

Chemopreventive effects and associated mechanisms of withaferin A (WA) against intestinal and colon carcinogenesis remain unknown. We investigated the chemopreventive effect of WA on transgenic adenomatous polyposis coli (APCMin/+) mouse and chemically induced azoxymethane/dextran sodium sulfate (AOM/DSS) models of intestinal and colon carcinogenesis. Oral WA administration (4 and 3 mg/kg) inhibited tumor initiation and progression of intestinal polyps formation in APCMin/+ mice and colon carcinogenesis in the AOM/DSS mouse model. WA-administered mice showed a significant reduction in both number [duodenum, 33% (P > 0.05); jejunum, 32% (P < 0.025); ileum, 43% ( P < 0.001); and colon 59% (P < 0.01] and size of polyps in APCMin/+ mice compared with the respective controls. Similarly, tumor multiplicity was significantly reduced (P < 0.05) in the colon of WA-administered AOM/DSS mice. Pathological analysis showed reduced adenomas and tissue inflammation in WA-administered mouse models. Molecular studies suggested that WA inhibited the expression of inflammatory (interluekin-6, tumor necrosis factor-alpha and cyclooxygenase-2), pro-survival (pAKT, Notch1 and NF-κB) markers in APCMin/+ and AOM/DSS models. The results suggest that WA is a potent agent for preventing colon carcinogenesis and further investigation is required to show clinical utility of the agent.

Bone and calcium metabolism associated with malignancy. Vitamin D and cancer.

Vitamin D deficiency and insufficiency are associated with an increased risk of colon cancer. The active form of vitamin D, 1α,25-dihydroxyvitamin D3[1,25(OH)2D3], inhibits proliferation and/or induces differentiation in cells derived from myeloid leukemia, colon cancer, breast cancer, prostate cancer and other malignancies. 1,25(OH)2D3 and its synthetic derivatives activate vitamin D receptor(VDR), a member of the nuclear receptor superfamily, and exhibit antitumor effects by regulating genes involved in cell cycle, differentiation, apoptosis, inflammation and angiogenesis. VDR activation also enhances metabolism of toxic bile acids, likely preventing colon carcinogenesis. Although many cell culture and animal experiments show that VDR is a promising drug target in the treatment of malignancy and many VDR ligands have been developed, a principal adverse effect of hypercalcemia has limited their clinical application. The development of VDR ligands with less calcemic activity is needed to expand clinical application of VDR-targeting therapy.

Augmented O-GlcNAcylation alleviates inflammation-mediated colon carcinogenesis via suppression of acute inflammation.

Colon cancer prevalence is high worldwide. O-GlcNAcylation has been associated with tumor growth in various tissues, including the colon; however, its link to carcinogenesis is not fully understood. We investigated the association of O-GlcNAcylation with colon carcinogenesis using a 1,2-dimethylhydrazine/dextran sodium sulfate-induced colon carcinogenesis model in wild type and O-GlcNAc transferase-transgenic (Ogt-Tg) mice. The incidence of colon cancer was significantly lower in Ogt-Tg than in wild type mice. The colonic length was not shortened in Ogt-Tg mice, and NF-κB p65 phosphorylation was strongly suppressed, indicating that reduction of inflammation might be related to the alleviation of colon carcinogenesis. Dextran sodium sulfate-induced acute colitis mice were used to evaluate the effect of O-GlcNAcylation on inflammation at the maximal inflammation period. In Ogt-Tg mice, NF-κB p65 phosphorylation and interleukin-1β mRNA expression were suppressed. Histochemical staining demonstrated shedding of colon epithelial cells in wild type mice a few days after dextran sodium sulfate treatment, whereas they remained essentially intact in Ogt-Tg mice. There were no significant differences on histochemical staining in the remaining epithelia between groups. These data suggest that O-GlcNAcylation could prevent colon carcinogenesis through reducing acute maximum inflammation, suggesting modulation of O-GlcNAcylation as a novel therapeutic option.

Feeding of the water extract from Ganoderma lingzhi to rats modulates secondary bile acids, intestinal microflora, mucins, and propionate important to colon cancer

Consumption of reishi mushroom has been reported to prevent colon carcinogenesis in rodents, although the underlying mechanisms remain unclear. To investigate this effect, rats were fed a high-fat diet supplemented with 5% water extract from either the reishi mushroom (Ganoderma lingzhi) (WGL) or the auto-digested reishi G. lingzhi (AWGL) for threeweeks. Both extracts markedly reduced fecal secondary bile acids, such as lithocholic acid and deoxycholic acid (colon carcinogens). These extracts reduced the numbers of Clostridium coccoides and Clostridium leptum (secondary bile acids-producing bacteria) in a per g of cecal digesta. Fecal mucins and cecal propionate were significantly elevated by both extracts, and fecal IgA was significantly elevated by WGL, but not by AWGL. These results suggest that the reishi extracts have an impact on colon luminal health by modulating secondary bile acids, microflora, mucins, and propionate that related to colon cancer.

P-259 - Evaluation of brachystegia eurycoma (harms) seed dietary inclusion in the prevention of colon carcinogenesis

P-259 - Evaluation of brachystegia eurycoma (harms) seed dietary inclusion in the prevention of colon carcinogenesis

Combined Parthenolide and Balsalazide Have Enhanced Antitumor Efficacy Through Blockade of NF-κB Activation.

This study represents the first evidence that combination therapy with balsalazide and parthenolide could be a new regimen for colorectal cancer treatment. Mol Cancer Res; 15(2); 141-51. ©2016 AACR.

Morin and Esculetin supplementation modulates c-myc induced energy metabolism and attenuates neoplastic changes in rats challenged with the procarcinogen 1,2 - dimethylhydrazine

Targeting tumor metabolism by natural products is a novel approach and provides rationale for anti-cancer drug discovery. The present study aims to explore the impact of morin and/or esculetin on c-myc induced energy metabolism in 1,2-dimethylhydrazine (DMH) induced colon cancer in rats. In order to achieve this aim we analyzed the expression of glucose and glutamine transporters and the key enzymes of glycolytic pathway besides the markers of neoplastic changes viz., mucin depleted foci (MDF), beta catenin accumulated crypts (BCAC), and markers of cell proliferation viz., proliferating cell nuclear antigen (PCNA), argyrophilic nucleolar antigen (AgNOR), c-myc, c-jun and c-fos. All the parameters tested in the present study are highly influenced by the phytochemicals morin and/or esculetin in a way to prevent colon carcinogenesis. Morin and/or esculetin supplementation effectively targets tumor metabolism via β-cateinin/c-myc signaling and affects glycolysis and glutaminolysis to abrogate colon cancer in rats. The anti-cancer effect of morin is more pronounced than esculetin. The effect obtained through the combined treatment of morin and esculetin is comparable to that of individual supplementation of morin and there is no synergistic effect. Overall individual supplementation of morin scores well as a potential anticancer agent targeting glycolysis and glutaminolysis in colon cancer.

Repression of MicroRNA Function Mediates Inflammation-associated Colon Tumorigenesis

Little is known about the mechanisms by which chronic inflammation contributes to carcinogenesis, such as the development of colon tumors in patients with inflammatory bowel diseases. Specific microRNA (miRNAs) can function as suppressors or oncogenes, and widespread alterations in miRNA expression have been associated with tumorigenesis. We studied whether alterations in miRNA function contribute to inflammation-associated colon carcinogenesis. We studied the effects of inflammatory cytokines, such as tumor necrosis factor, interleukin-1α (IL1A), and IL1β (IL1B), on miRNA function, measured by activity of reporter constructs containing miRNA-binding sites in their 3' untranslated regions, in human 293T embryonic kidney, Caco-2, HT29, and HCT116 colon carcinoma cells, as well as dicer+/+ and dicer-/-, and Apobec3+/+ and Apobec3-/- mouse embryonic fibroblasts. Cells were analyzed by immunoblots, immunohistochemistry, and flow cytometry. We generated transgenic mice expressing reporter constructs regulated by LET7B, MIR122, and MIR29b response elements; some mice were given injections of miRNA inhibitors (anti-MIR122 or anti-LET7B), a negative control, or tumor necrosis factor. Liver tissues were collected and analyzed by immunoblotting. Reporter mice were given azoxymethane followed by dextran sulfate sodium to induce colitis and colon tumors; some mice were given the ROCK inhibitor fasudil along with these agents (ROCK inhibitors increase miRNA function). Colon tissues were collected and analyzed by immunohistochemistry, immunoblots, and fluorescence microscopy. Incubation of cell lines with inflammatory cytokines reduced the ability of miRNAs to down-regulate expression from reporter constructs; dicer was required for this effect, so these cytokines relieve miRNA-dependent reductions in expression. The cytokines promoted degradation of APOBEC3G, which normally promotes miRNA loading into argonaute 2-related complexes. Mice with colitis had reduced miRNA function, based on increased expression of reporter genes. Administration of fasudil to mice did not reduce the severity of colitis that developed but greatly reduced the numbers of colon tumors formed (mean 2 tumors/colon in mice given fasudil vs 9 tumors/colon in mice given control agent). We made similar observations in IL10-deficient mice. We found inflammatory cytokines to reduce the activities of miRNAs. In mice with colitis, activities of miRNAs are reduced; administration of an agent that increases miRNA function prevents colon tumor formation in these mice. This pathway might be targeted to prevent colon carcinogenesis in patients with inflammatory bowel diseases.

Development of a potential probiotic yoghurt using selected anti-inflammatory lactic acid bacteria for prevention of colitis and carcinogenesis in mice.

To evaluate the beneficial properties of a potentially probiotic yoghurt obtained by the fermentation of two selected anti-inflammatory bacterial strains using invivo mouse models of intestinal inflammation and colon carcinogenesis. Yoghurt was administered to mice suffering chemically induced intestinal inflammation or colon carcinogenesis. It was shown that this novel yoghurt was able to prevent local inflammation in the intestines of mice through a regulation of the immune response, prevent macroscopic and histological damages, and prevent colon carcinogenesis through an anti-inflammatory response. The developed yoghurt showed invivo anti-inflammatory properties by modulation of the host immune response for the prevention of colon inflammation and carcinogenesis. This new yoghurt could thus be considered a probiotic food and be useful as a complement to current treatment protocols for inflammatory bowel diseases and colon cancer, a first since there are no current functional foods specifically oriented for these patients.

The epigenetic effects of aspirin: the modification of histone H3 lysine 27 acetylation in the prevention of colon carcinogenesis in azoxymethane- and dextran sulfate sodium-treated CF-1 mice.

Colorectal cancer (CRC) is the third most common cancer worldwide. Chronic inflammation appears to enhance the risk of CRC. Emerging evidence has suggested that epigenetic mechanisms play an important role in CRC. Aspirin [acetylsalicylic acid (ASA)] has been shown to prevent CRC; however, the epigenetic mechanisms of its action remain unknown. This study investigated the protective role of ASA in azoxymethane (AOM)-initiated and dextran sulfate sodium (DSS)-promoted colitis-associated colon cancer (CAC) and examined the epigenetic effects, particularly on histone 3 lysine 27 acetylation (H3K27ac), underlying the preventive effect of ASA. CF-1 mice were fed with AIN-93M diet with or without 0.02% ASA from 1 week prior to AOM initiation until the mice were killed 20 weeks after AOM injection. Our results showed that AOM/DSS + ASA significantly suppressed inflammatory colitis symptoms and tumor multiplicity. AOM/DSS + ASA reduced AOM/DSS-induced protein expression and the activity of histone deacetylases (HDACs) and globally restored H3K27ac. Furthermore, AOM/DSS + ASA inhibited AOM/DSS-induced enrichment of H3K27ac in the promoters of inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) that corresponded to the dramatic suppression of the messenger RNA (mRNA) and protein levels. Surprisingly, no significant changes in the H3K27ac abundance in the prostaglandin-endoperoxide synthase 2 (Cox-2) promoters or in the Cox-2 mRNA and protein expression were observed. Collectively, our results suggest that a potential novel epigenetic mechanism underlies the chemopreventive effects of ASA, and this mechanism attenuates CAC in AOM/DSS-induced CF-1 mice via the inhibition of HDACs and the modification of H3K27ac marks that suppress iNOS, TNF-α and IL-6.

Dietary magnesium, calcium:magnesium ratio and risk of reflux oesophagitis, Barrett's oesophagus and oesophageal adenocarcinoma: a population-based case-control study.

Evidence suggests a role of Mg and the ratio of Ca:Mg intakes in the prevention of colonic carcinogenesis. The association between these nutrients and oesophageal adenocarcinoma - a tumour with increasing incidence in developed countries and poor survival rates - has yet to be explored. The aim of this investigation was to explore the association between Mg intake and related nutrients and risk of oesophageal adenocarcinoma and its precursor conditions, Barrett's oesophagus and reflux oesophagitis. This analysis included cases of oesophageal adenocarcinoma (n 218), Barrett's oesophagus (n 212), reflux oesophagitis (n 208) and population-based controls (n 252) recruited between 2002 and 2005 throughout the island of Ireland. All the subjects completed a 101-item FFQ. Unconditional logistic regression analysis was applied to determine odds of disease according to dietary intakes of Mg, Ca and Ca:Mg ratio. After adjustment for potential confounders, individuals consuming the highest amounts of Mg from foods had significant reductions in the odds of reflux oesophagitis (OR 0·31; 95 % CI 0·11, 0·87) and Barrett's oesophagus (OR 0·29; 95 % CI 0·12, 0·71) compared with individuals consuming the lowest amounts of Mg. The protective effect of Mg was more apparent in the context of a low Ca:Mg intake ratio. No significant associations were observed for Mg intake and oesophageal adenocarcinoma risk (OR 0·77; 95 % CI 0·30, 1·99 comparing the highest and the lowest tertiles of consumption). In conclusion, dietary Mg intakes were inversely associated with reflux oesophagitis and Barrett's oesophagus risk in this Irish population.

PWE-180 Dietary magnesium, calcium:magnesium ratio and risk of reflux oesophagitis, barrett’s oesophagus and oesophageal adenocarcinoma

Introduction Recent evidence suggests a role for magnesium, and the ratio of calcium-to-magnesium, intake in the prevention of colonic carcinogenesis. However, the association between these nutrients and oesophageal adenocarcinoma has yet to be explored. The aim of this investigation was to explore the association between the intake of magnesium and related nutrients and the risk of oesophageal adenocarcinoma and its pre-cursor conditions, Barrett’s oesophagus and reflux oesophagitis. Method This analysis included cases of oesophageal adenocarcinoma (n = 2 n = 218), Barrett’s oesophagus (n = 2 n = 212), reflux oesophagitis (n = 2 n = 208) and population-based controls (n = 2 n = 252) recruited between 2002 and 2005 throughout the island of Ireland. All subjects completed a 101-item food frequency questionnaire. Unconditional logistic regression analysis was applied to determine odds of disease according to the dietary intakes of magnesium, calcium, and the resulting calcium:magnesium ratio. Results After adjustment for potential confounders, individuals consuming the highest magnesium intakes from foods had significant reductions in the odds of reflux oesophagitis (OR 0.31, 95% CI: 0.11–0.87) and Barrett’s oesophagus (OR 0.29, 95% CI: 0.12–0.71) compared with individuals consuming the lowest magnesium intakes. The protective effect of magnesium was more apparent in the context of a low calcium:magnesium intake ratio. No significant associations were observed for magnesium intake and oesophageal adenocarcinoma risk (OR 0.77, 95% CI: 0.30–1.99 comparing the highest and lowest tertiles of consumption). Conclusion Dietary magnesium intakes were inversely associated with reflux oesophagitis and Barrett’s oesophagus risk in this Irish population, suggesting a chemopreventive role for magnesium in the earlier stages of the inflammation-metaplasia-adenocarcinoma pathway. Further observational studies are needed to determine if dietary interventions are warranted. Disclosure of interest None Declared.

Kimchi protects against azoxymethane/dextran sulfate sodium-induced colorectal carcinogenesis in mice.

The chemopreventive effects of different types and quantities of kimchi prepared with different subingredients, including commercial kimchi (CK), standardized kimchi (SK), cancer-preventive kimchi (CPK), and anticancer kimchi (ACK), on colorectal carcinogenesis in mice were evaluated. The development of colon cancer was induced in male BALB/c mice with a single intraperitoneal injection of azoxymethane (AOM, 10 mg/kg body weight) and subsequent treatment with 2% dextran sulfate sodium (DSS) in drinking water for 7 days for two cycles. After exposure to AOM and DSS, treatment with the methanolic extracts from different kimchis, particularly 1.89 g/kg of ACK, significantly increased colon length, decreased the ratio of colon weight/length, and resulted in the lowest number of tumors compared with the other kimchi-treated groups. Histological observation revealed that ACK was able to suppress AOM- and DSS-induced colonic mucosal damage and neoplasia. ACK also significantly decreased the mRNA levels of proinflammatory cytokines (TNF-α, IL-6, and IFN-γ) as well as the mRNA and protein expression of inducible nitric oxide synthase and cyclooxygenase-2 (COX-2). In addition, the mRNA and protein expression of p53 and p21 was elevated in colon tissues from the ACK-treated mice compared with the other kimchi-treated groups. Our results suggest that kimchi exerted a suppressive effect on AOM- and DSS-induced colorectal carcinogenesis in the BALB/c mice. The anticancer effects of ACK were particularly potent. Thus, it is possible that the health-promoting subingredients added to ACK might be used to prevent colon carcinogenesis in humans.