Effects of non-digestible carbohydrates on gut microbiota and microbial metabolites: a randomised, controlled dietary intervention in healthy individuals.

The gut microbiome is impacted by certain types of dietary fibre. However, the type, duration and dose needed to elicit gut microbial changes and whether these changes also influence microbial metabolites remain unclear. This study investigated the effects of supplementing healthy participants with two types of non-digestible carbohydrates (resistant starch (RS) and polydextrose (PD)) on the stool microbiota and microbial metabolite concentrations in plasma, stool and urine, as secondary outcomes in the Dietary Intervention Stem Cells and Colorectal Cancer (DISC) Study.

Efficient gene replacement by CRISPR/Cas-mediated homologous recombination in the model diatom Thalassiosira pseudonana.

CRISPR/Cas enables targeted genome editing in many different plant and algal species including the model diatom Thalassiosira pseudonana. However, efficient gene targeting by homologous recombination (HR) to date is only reported for photosynthetic organisms in their haploid life-cycle phase. Here, a CRISPR/Cas construct, assembled using Golden Gate cloning, enabled highly efficient HR in a diploid photosynthetic organism.

Resistant starch supplementation increases crypt cell proliferative state in the rectal mucosa of older healthy participants.

There is strong evidence that foods containing dietary fibre protect against colorectal cancer, resulting at least in part from its anti-proliferative properties. This study aimed to investigate the effects of supplementation with two non-digestible carbohydrates, resistant starch (RS) and polydextrose (PD), on crypt cell proliferative state (CCPS) in the macroscopically normal rectal mucosa of healthy individuals. We also investigated relationships between expression of regulators of apoptosis and of the cell cycle on markers of CCPS.

The Role of Self-Determination in Changing Physical Activity Behavior in People Diagnosed With Bowel Polyps: A Pilot Randomized Controlled Trial.

This nonblinded randomized controlled trial investigated the efficacy of a physical activity (PA) intervention underpinned by self-determination theory. Participants (N = 31, mean age 69 years [SD = 4.9]) diagnosed with bowel polyps were randomized to an active lifestyle program (ALP; n = 17) or standard care (n = 14).

Adherence to the World Cancer Research Fund/American Institute for Cancer Research cancer prevention recommendations and WNT-pathway-related markers of bowel cancer risk.

Bowel cancer risk is strongly influenced by lifestyle factors including diet and physical activity. Several studies have investigated the effects of adherence to the World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) cancer prevention recommendations on outcomes such as all-cause and cancer-specific mortality, but the relationships with molecular mechanisms that underlie the effects on bowel cancer risk are unknown. This study aimed to investigate the relationships between adherence to the WCRF/AICR cancer prevention recommendations and wingless/integrated (WNT)-pathway-related markers of bowel cancer risk, including the expression of WNT pathway genes and regulatory microRNA (miRNA), secreted frizzled-related protein 1 (SFRP1) methylation and colonic crypt proliferative state in colorectal mucosal biopsies.

Genome Editing in Diatoms Using CRISPR-Cas to Induce Precise Bi-allelic Deletions.

Genome editing in diatoms has recently been established for the model species and . The present protocol, although developed for , can be modified to edit any diatom genome as we utilize the flexible, modular Golden Gate cloning system. The main steps include how to design a construct using Golden Gate cloning for targeting two sites, allowing a precise deletion to be introduced into the target gene.

Non-digestible carbohydrates supplementation increases miR-32 expression in the healthy human colorectal epithelium: A randomized controlled trial.

Colorectal cancer (CRC) risk is modulated by diet and there is convincing evidence of reduced risk with higher non-digestible carbohydrates (NDCs) consumption. Resistant starch (RS), a NDC, positively modulates the expression of oncogenic microRNAs, suggesting that this could be a mechanism through which NDCs protect against CRC. The present study aimed to investigate the effects of supplementation with two NDCs, RS, and polydextrose (PD), on microRNA expression in the macroscopically-normal human rectal epithelium using samples from the DISC Study, a randomized, double-blind, placebo-controlled dietary intervention.

Effects of supplementation with nondigestible carbohydrates on fecal calprotectin and on epigenetic regulation of SFRP1 expression in the large-bowel mucosa of healthy individuals.

Background: Hyperactive Wnt signaling is frequently observed in colorectal cancer. Higher intakes of dietary fiber [nondigestible carbohydrates (NDCs)] and the fermentation product butyrate are protective against colorectal cancer and may exert their preventative effects via modulation of the Wnt pathway.

Objectives: We investigated the effects of supplementing healthy individuals with 2 NDCs [resistant starch (RS) and polydextrose] on fecal calprotectin concentrations and Wnt pathway-related gene expression.

Modified sugar beet pectin induces apoptosis of colon cancer cells via an interaction with the neutral sugar side-chains.

Pectins extracted from a variety of sources and modified with heat and/or pH have previously been shown to exhibit activity towards several cancer cell lines. However, the structural basis for the anti-cancer activity of modified pectin requires clarification. Sugar beet and citrus pectin extracts have been compared.

Phytochemical Indicaxanthin Inhibits Colon Cancer Cell Growth and Affects the DNA Methylation Status by Influencing Epigenetically Modifying Enzyme Expression and Activity.

Background: Recently, we have shown anti-proliferative and pro-apoptotic effects of indicaxanthin associated with epigenetic modulation of the onco-suppressor p16INK4a in the human colon cancer cell line CACO2. In the present study, the epigenetic activity of indicaxanthin and the mechanisms involved were further investigated in other colorectal cancer cell lines.

Methods: LOVO1, CACO2, HT29, HCT116, and DLD1 cells were used to evaluate the potential influence of consistent dietary concentrations of indicaxanthin on DNA methylation, and the epigenetic mechanisms involved were researched.

Rhamnogalacturonan I containing homogalacturonan inhibits colon cancer cell proliferation by decreasing ICAM1 expression.

Pectin modified with pH, heat or enzymes, has previously been shown to exhibit anti-cancer activity. However, the structural requirements for modified pectin bioactivity have rarely been addressed. In this study several pectin extracts representing different structural components of pectin were assessed for effects against colon cancer cells.

The effect of diet on the intestinal epigenome.

The colorectal mucosal epithelium is composed of rapidly proliferating crypt cells derived by clonal expansion from stem cells. The aging human colorectal mucosa develops aberrant patterns of DNA methylation that may contribute to its increasing vulnerability to cancer. Various types of evidence suggest that age-dependent loss of global methylation, together with hypermethylation of CpG islands associated with cancer-related genes, may be influenced by nutritional and metabolic factors.

Procyanidin induces apoptosis of esophageal adenocarcinoma cells via JNK activation of c-Jun.

Procyanidins are polymeric flavanols found in fruits and vegetables and have shown anticarcinogenic/chemopreventive properties. We previously showed that oligomeric procyanidin extracted from apples induced cell cycle arrest and apoptosis in esophageal adenocarcinoma (OA) cells. To understand the mechanism of action, we determined transcriptomic changes induced by procyanidin in OA cells.

Nutritional factors and gender influence age-related DNA methylation in the human rectal mucosa.

Aberrant methylation of CpG islands (CGI) occurs in many genes expressed in colonic epithelial cells, and may contribute to the dysregulation of signalling pathways associated with carcinogenesis. This cross-sectional study assessed the relative importance of age, nutritional exposures and other environmental factors in the development of CGI methylation. Rectal biopsies were obtained from 185 individuals (84 male, 101 female) shown to be free of colorectal disease, and for whom measurements of age, body size, nutritional status and blood cell counts were available.

Colorectal cancer cells Caco-2 and HCT116 resist epigenetic effects of isothiocyanates and selenium in vitro.

Purpose: It is relatively unknown how different dietary components, in partnership, regulate gene expression linked to colon pathology. It has been suggested that the combination of various bioactive components present in a plant-based diet is crucial for their potential anticancer activities. This study employed a combinatorial chemopreventive strategy to investigate the impact of selenium and/or isothiocyanates on DNA methylation processes in colorectal carcinoma cell lines.

TrxR1 and GPx2 are potently induced by isothiocyanates and selenium, and mutually cooperate to protect Caco-2 cells against free radical-mediated cell death.

Currently, there is significant interest in the field of diet-gene interactions and the mechanisms by which food compounds regulate gene expression to modify cancer susceptibility. From a nutrition perspective, two key components potentially exert cancer chemopreventive effects: isothiocyanates (ITCs), present in cruciferous vegetables, and selenium (Se) which, as selenocysteine, is an integral part of selenoproteins. However, the role of these compounds in the expression of key selenoenzymes once the cancer process has been initiated still needs elucidation.

Quantitative profiling of CpG island methylation in human stool for colorectal cancer detection.

Purpose: The aims of this study were to investigate the use of quantitative CGI methylation data from stool DNA to classify colon cancer patients and to relate stool CGI methylation levels to those found in corresponding tissue samples.

Methods: We applied a quantitative methylation-specific PCR assay to determine CGI methylation levels of six genes, previously shown to be aberrantly methylated during colorectal carcinogenesis. Assays were performed on DNA from biopsies of "normal" mucosa and stool samples from 57 patients classified as disease-free, adenoma, or cancer by endoscopy, and in tumour tissue from cancer patients.

Supra-physiological folic acid concentrations induce aberrant DNA methylation in normal human cells in vitro.

The micronutrients folate and selenium may modulate DNA methylation patterns by affecting intracellular levels of the methyl donor S-adenosylmethionine (SAM) and/or the product of methylation reactions S-adenosylhomocysteine (SAH). WI-38 fibroblasts and FHC colon epithelial cells were cultured in the presence of two forms of folate or four forms of selenium at physiologically-relevant doses, and their effects on LINE-1 methylation, gene-specific CpG island (CGI) methylation and intracellular SAM:SAH were determined. At physiologically-relevant doses the forms of folate or selenium had no effect on LINE-1 or CGI methylation, nor on intracellular SAM:SAH.

Epigenetic and antioxidant effects of dietary isothiocyanates and selenium: potential implications for cancer chemoprevention.

There is evidence from epidemiological studies suggesting that increased consumption of cruciferous vegetables may protect against specific cancers more effectively than total fruit and vegetable intake. These beneficial effects are attributed to the glucosinolate breakdown products, isothiocyanates (ITC). Similarly, selenium (Se) consumption has also been inversely associated with cancer risk and as an integral part of many selenoproteins may influence multiple pathways in the development of cancer.

Recent advances in understanding the role of diet and obesity in the development of colorectal cancer.

Colorectal cancer (CRC) is a major cause of premature death in the UK and many developed countries. However, the risk of developing CRC is well recognised to be associated not only with diet but also with obesity and lack of exercise. While epidemiological evidence shows an association with factors such as high red meat intake and low intake of vegetables, fibre and fish, the mechanisms underlying these effects are only now being elucidated.

Patterns of DNA methylation in individual colonic crypts reveal aging and cancer-related field defects in the morphologically normal mucosa.

Methylation of CpG islands (CGIs) in the promoter regions of tumour suppressor genes is common in colorectal cancer and occurs also in an age-dependent manner in the morphologically normal colorectal mucosa. In this study, we quantified the level of methylation of six genes associated with the Wnt signalling pathway (adenomatous polyposis coli, DKK1, WIF1, SFRP1, SFRP2 and SFRP5) together with long-interspersed nuclear element-1 as a surrogate for global methylation. DNA methylation was analysed in 260 individual colorectal crypts obtained from eight female patients with no evidence of colorectal disease and five with colorectal cancer.

Procyanidin effects on oesophageal adenocarcinoma cells strongly depend on flavan-3-ol degree of polymerization.

Epidemiological studies have shown that the risk of developing oesophageal adenocarcinoma (OA) is inversely correlated to consumption of fruits and vegetables. Flavan-3-ols are the most abundant subclass of flavonoids in these types of foods. Three apple-derived procyanidin fractions with different average degrees of polymerization (aDP) were characterized and the effects of these fractions and of pure flavan-3-ol monomers ((-)-epicatechin and (+)-catechin) and dimers (B1, B2) on two OA cell lines were investigated.

Flavonoids and intestinal cancers.

Cancers of the gastrointestinal tract are amongst the most common causes of death from cancer, but there is substantial variation in incidence across populations. This is consistent with a major causative role for diet. There is convincing evidence that fruits and vegetables protect against cancers of the upper alimentary tract and the large bowel, and this has focused attention on biologically active phytochemicals, and on flavonoids in particular.

Environment, diet and CpG island methylation: epigenetic signals in gastrointestinal neoplasia.

The epithelial surfaces of the mammalian alimentary tract are characterised by very high rates of cell proliferation and DNA synthesis, and in humans they are highly susceptible to cancer. The role of somatic mutations as drivers of carcinogenesis in the alimentary tract is well established, but the importance of gene silencing by epigenetic mechanisms is increasingly recognised. Methylation of CpG islands is an important component of the epigenetic code that regulates gene expression during development and normal cellular differentiation, and a number of genes are well known to become abnormally methylated during the development of tumours of the oesophagus, stomach and colorectum.