Protective effects of butyric acid in colon cancer

Antiproliferative and antioxidant effect of polar hemp extracts (Cannabis sativa L., Fedora cv.) in human colorectal cell lines

Total phenolic content and antioxidant activity of polar extracts of edible resources from Fedora hemp cultivar (Cannabis sativa L.), namely seed, flour and oil, were evaluated. The main components in the polar extracts were identified using HPLC-DAD and HPLC-ESI-MS/MS. As expected, the molecular profile of components from seeds and flour was strictly similar, dominated by N-trans-caffeoyltyramine. The profile of oil polar extracts contained hydroxycinnamic acid derivatives and cannabinoids at lower extent. While the extracts from hemp seed and flour did not interfere with growth of Caco-2 and HT-29 cell, the one from oil (150 µg/mL) significantly reduced cell viability after 24 h of treatment. This effect was associated with the activation of apoptotic cell death and was independent from the antioxidant capacity of the oil polar extract. Notably, HT-29 cells differentiated with sodium butyrate were not sensitive to the cytotoxic effect of the oil extract.

Effects of the modulation of microbiota on the gastrointestinal immune system and bowel function

The gastrointestinal tract harbors a tremendous number and variety of commensal microbiota. The intestinal mucosa simultaneously absorbs essential nutrients and protects against detrimental antigens or pathogenic microbiota as the first line of defense. Beneficial interactions between the host and microbiota are key requirements for host health. Although the gut microbiota has been previously studied in the context of inflammatory diseases, it has recently become clear that this microbial environment has a beneficial role during normal homeostasis, by modulating the immune system or bowel motor function. Recent studies revealed that microbiota, including their metabolites, modulate key signaling pathways involved in the inflammation of the mucosa or the neurotransmitter system in the gut-brain axis. The underlying molecular mechanisms of host-microbiota interactions are still unclear; however, manipulation of microbiota by probiotics or prebiotics is becoming increasingly recognized as an important therapeutic option, especially for the treatment of the dysfunction or inflammation of the intestinal tract.

Prebiotic treatment reduced preneoplastic lesions through the downregulation of toll like receptor 4 in a chemo-induced carcinogenic model

Germinated barley foodstuff contains prebiotics which are reported to have anti-cancerous effects in colorectal cancer model, but the detailed mechanism remains unclear. Recent studies revealed that the role of microbiota was strongly related to the regulation of incidence and progression of colorectal cancer. The aim of this study was to examine the anti-neoplastic mechanism by prebiotics. Azoxymethane treated F344 rats were used as the sporadic cancerous model. After azoxymethane injection, either a control or germinated barley foodstuff diet was administered to the rats for another 5 weeks, and the number of abberant crypt foci, toll like receptor 4, Kirsten rat sarcoma viral oncogene homolog, adenomatous polyposis coli tumor suppressor gene and cyclooxygenase 2 mRNA expression of colonic mucosa and cecal short chain fatty acids were examined. The germinated barley food stuff significantly attenuated the number of abberant crypt focis and the expression of toll like receptor 4 and cyclooxygenase 2 mRNA, compared to the control group. In addition, the cecal butyrate production in the germinated barley foodstuff group was significantly higher than that in the control. In conclusion, this prebiotic treatment for colorectal cancer may be useful without causing the adverse effects seen in either anti-cancer drugs or anti-inflammatory drugs.

Butyrate, an HDAC inhibitor, stimulates interplay between different posttranslational modifications of histone H3 and differently alters G1-specific cell cycle proteins in vascular smooth muscle cells

HDACs and HATs regulate histone acetylation, an epigenetic modification that controls chromatin structure and through it, gene expression. Butyrate, a dietary HDAC inhibitor, inhibits VSMC proliferation, a crucial factor in atherogenesis, and the principle mechanism in arterial and in-stent restenosis. Here, the link between antiproliferation action of butyrate and the portraits of global covalent modifications of histone H3 that it induces are characterized to understand the mechanics of butyrate-arrested VSMC proliferation. Analysis of histone H3 modifications specific to butyrate arrested VSMC proliferation display induction of histone H3-Lysine9 acetylation, inhibition of histone H3-Serine10 phosphorylation, reduction of histone H3-Lysine9 dimethylation and stimulation of histone H3-Lysine4 di-methylation, which is linked to transcriptional activation, cell cycle/mitosis, transcriptional suppression and activation, respectively. Conversely, untreated VSMCs exhibit inhibition of H3-Lysine9 acetylation, induction of H3-Serine10 phosphorylation, stimulation of H3-Lysine9 di-methylation and reduction in H3-Lysine4 di-methylation. Butyrate's cooperative effects on H3-Lysine9 acetylation and H3-Serine10 phosphorylation, and contrasting effects on di-methylation of H3-Lysine9 and H3-Lysine4 suggests that the interplay between these site-specific modifications cause distinct chromatin alterations that allow cyclin D1 and D3 induction, G1-specific cdk4, cdk6 and cdk2 downregulation, and upregulation of cdk inhibitors, p15INK4b and p21Cip1. Regardless of butyrate's effect on D-type cyclins, downregulation of G1-specific cdks and upregulation of cdk inhibitors by butyrate prevents cell cycle progression by failing to inactivate Rb. Overall, through chromatin remodeling, butyrate appears to differentially alter G1-specific cell cycle proteins to ensure proliferation arrest of VSMCs, a crucial cellular component of blood vessel wall.

Effects of histone deacetylase inhibitors on p55CDC/Cdc20 expression in HT29 cell line

In a previous work, taking advantage of the gene-array screening technology, we analysed the effects of histone deacetylase (HDAC) inhibitor sodium butyrate (NaBt), on gene transcription in HT29 human adenocarcinoma cell line. In this study, we focused our attention on p55CDC/Cdc20 gene, whose expression was dramatically reduced by NaBt treatment. Mammalian p55CDC/Cdc20 interacts with the anaphase promoting complex/cyclosome (APC/C), and is involved in regulating anaphase onset and late mitotic events. Using NaBt and trichostatin A (TSA), a member of the HDAC inhibitor family, we showed that both HDAC inhibitors totally downregulated p55CDC/Cdc20 transcription and expression. Cell cycle analysis demonstrated that NaBt arrested HT29 cells in G0/G1 phase, while TSA caused a double block in G0/G1 and G2/M phases. Moreover, p55CDC/Cdc20 showed maximal expression in S and G2/M phases of HT29 cell division cycle. Based on this evidence, and by means of specific cell cycle modulators, such as nocodazole and hydroxyurea, we demonstrated that both TSA and NaBt were responsible for loss of p55CDC/Cdc20 expression, but with different mechanisms of action. Taken together, these results suggest that targeting molecules involved in spindle mitotic checkpoint, such as p55CDC/Cdc20, might account for the high cytotoxicity of HDAC inhibitors versus malignant cells.

Effects of a 3-mo consumption of short-chain fructo-oligosaccharides on parameters of colorectal carcinogenesis in patients with or without small or large colorectal adenomas

Intervention studies of colorectal adenoma recurrence have demonstrated the need for surrogate markers of the cancer risk. Short-chain fructo-oligosaccharides (sc-FOS) have protective actions on colon carcinogenesis in animal models. We investigated differences in biological markers between adenoma and adenoma-free subjects, before and after 3 mo of daily intake of 10 g sc-FOS, within a multicenter study. After a full colonoscopy, 3 groups were studied at baseline and after 3 mo: 26 subjects with small colorectal adenoma(s), 18 with large adenoma(s), and 30 with no adenoma. At baseline, the mean fecal butyrate concentration was significantly lower in the adenoma groups than in the adenoma-free group (12.01 +/- 5.08 vs. 17.28 +/- 7.34 mmol/g dry weight) but was significantly increased in that group after 3-mo ingestion of sc-FOS (15.7 +/- 8.0 mmol/g; P = 0.02). In subjects without adenoma, sc-FOS ingestion was associated with a decrease in fecal lithocholic acid (P = 0.02) and an increase in cholic acid (P = 0.02), chenodeoxycholic acid (P = 0.04), total primary bile acids (P = 0.03), and ursodeoxycholic acid (P = 0.05). Fecal pH, blood parameters, and crypt cell proliferation were not significantly modified by sc-FOS ingestion in either group. In subjects with and without adenoma, sc-FOS affects some aspects of the colonic environment, which may be involved in prevention of colorectal neoplasia.

Consumption of dairy products in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort: data from 35 955 24-hour dietary recalls in 10 European countries

OBJECTIVES

To describe and compare the consumption of dairy products in cohorts included in the European Prospective Investigation into Cancer and Nutrition (EPIC).

METHODS

Data from single 24-hour dietary recall interviews collected through a highly standardised computer-based program (EPIC-SOFT) in 27 redefined centres in 10 European countries between 1995 and 2000. From a total random sample of 36 900, 22 924 women and 13 031 men were selected after exclusion of subjects under 35 and over 74 years of age.

RESULTS

A high total consumption of dairy products was reported in most of the centres in Spain and in the UK cohort sampled from the general population, as well as in the Dutch, Swedish and Danish centres. A somewhat low consumption was reported in the Greek centre and in some of the Italian centres (Ragusa and Turin). In all centres and for both sexes, milk constituted the dairy sub-group with the largest proportion (in grams) of total dairy consumption, followed by yoghurt and other fermented milk products, and cheese. Still, there was a wide range in the contributions of the different dairy sub-groups between centres. The Spanish and Nordic centres generally reported a high consumption of milk, the Swedish and Dutch centres reported a high consumption of yoghurt and other fermented milk products, whereas the highest consumption of cheese was reported in the French centres.

CONCLUSION

The results demonstrate both quantitative and qualitative disparities in dairy product consumption among the EPIC centres. This offers a sound starting point for analyses of associations between dairy intake and chronic diseases such as cancer.

Primary prevention: phytoprevention and chemoprevention of colorectal cancer

Considering the various stages of carcinogenesis and the numerous tumor types and available chemoprevention agents, knowledge of the etiology and the type of cancer to be treated, or possibly prevented, and understanding of the mechanisms by which agents exert their chemoprevention benefits may provide for improved strategy in designing therapeutic regimens. Because cancer usually develops over a 10- to 20-year period, it may be necessary for some agents to be provided before or early in the initiation steps of carcinogenesis to have beneficial effects. On the other hand, some agents may be more suitable for CRC prevention if provided at a later stage of carcinogenesis. Gene array, genomics, and proteomics are useful tools in advancing our understanding of the molecular events involved in carcinogenesis and in identifying markers of risk and surrogate end-points for colorectal cancer progression. These techniques may also serve for screening, identifying, and providing treatment targets for high-risk patients populations. Treatment could be developed depending on a patient's individual needs and genomic tumor profile. Clinical markers and surrogate end-points should be considered, together with molecular measurements, to more accurately assess risk. NSAIDs and COXIBs are clinically recognized as chemoprevention agents, and clinical trials evaluating their efficacy are ongoing. Treatment protocols, including dose and timing, remain to be determined, however. DFMO may best be used in combination with other chemoprevention agents. Dietary fiber and calcium supplements, as part of an overall low-fat diet, may decrease CRC risk. Long-term compliance with this regimen may be necessary to effect a beneficial outcome. Folate holds promise but needs further investigation, especially because its beneficial effects may depend on cancer type. Phytochemicals have been identified as strong candidates for use as agents to prevent colorectal cancer in cell culture and in rodent models of carcinogenesis. Their potential as chemoprevention agents must be demonstrated in clinical trials. In vitro and animal studies indicated that combination therapy may be a promising strategy over the monotherapy approach; clinical trials addressing the safety and efficacy of some combinations (DFMO/sulindac, fiber/calcium) are underway. The gastrointestinal tract and other organs are constantly exposed to a mixture of potentially toxic compounds and molecules considered favorable to health. Homeostasis between stress-mediated by toxic compounds and defensive mechanisms, is key for the maintenance of health and the prevention of disease. Whereas aggressive pharmacologic treatment may be necessary for patients at high risk for cancer, dietary supplements may be useful for populations at normal risk. The message for cancer prevention in the general population may well remain: keep a balanced healthy diet, eating a variety from all food groups, as part of a healthy lifestyle that includes moderate exercise.

Transcriptional response of a human colon adenocarcinoma cell line to sodium butyrate

Taking advantage of the DNA array screening technology, we analysed the effect of sodium butyrate on mRNA transcription in human HT29 colon adenocarcinoma cells. Out of 588 mRNA species analysed, only 119 resulted expressed. Among these, 60 exhibited a variable degree of modulation after butyrate treatment. Genes linked to the cell growth, apoptosis and oxidative metabolism appeared the most significantly affected. Furthermore, many of the differentially expressed genes are transcription factors and this may account for the variability of the biological effects of butyrate. The pattern of butyrate-affected genes may represent a reference in further analyses of gene expression of intestinal cells and tissues.

Diet and cancer prevention

Research from several sources provides strong evidence that vegetables, fruits, and whole grains, dietary fibre, certain micronutrients, some fatty acids and physical activity protect against some cancers. In contrast, other factors, such as obesity, alcohol, some fatty acids and food preparation methods may increase risks. Unravelling the multitude of plausible mechanisms for the effects of dietary factors on cancer risk will likely necessitate that nutrition research moves beyond traditional epidemiological and metabolic studies. Nutritional sciences must build on recent advances in molecular biology and genetics to move the discipline from being largely 'observational' to focusing on 'cause and effect'. Such basic research is fundamental to cancer prevention strategies that incorporate effective dietary interventions for target populations.

Inhibition by deacetylase inhibitors of IL-1-dependent induction of haptoglobin involves CCAAT/Enhancer-binding protein isoforms in intestinal epithelial cells

Intestinal epithelial cells participate in an acute phase response (APR) by responding to cytokines and by expressing acute phase protein genes. We hypothesized that butyrate, a fermentation product of the bacterial intestinal flora with deacetylase activity, affects the APR in intestinal epithelial cells. Sodium butyrate (NaBu) and Trichostatin A (TSA) induced alkaline phosphatase activity and histone H4 acetylation in IEC-6 rat intestinal epithelial cells treated with or without interleukin-1beta (IL-1). In contrast, both NaBu and TSA attenuated the IL-1-dependent induction of the acute phase protein gene haptoglobin, as well as C/EBPbeta and C/EBPdelta transcription factors mRNAs. Gel shift and supershift assays showed a strong decrease in the IL-1-induced C/EBPbeta and C/EBPdelta containing complexes binding to the HaptoA C/EBP DNA-binding site of the haptoglobin promoter, by NaBu and TSA. Furthermore, site-specific mutation of the HaptoA site abolished the NaBu- and TSA-dependent inhibition of haptoglobin, as determined by transient transfection assays. These results suggest that deacetylase inhibitors may regulate the IL-1 dependent induction of haptoglobin by down-regulating C/EBP isoforms, and that C/EBPs represent a target for the action of butyrate in the control of the APR of intestinal epithelial cells.