Phytochemicals and colorectal cancer prevention--myth or reality?

NADPH oxidase 1: A target in the capacity of dimeric ECG and EGCG procyanidins to inhibit colorectal cancer cell invasion

Colorectal cancer (CRC) is prevalent worldwide. Dietary consumption of procyanidins has been linked to a reduced risk of developing CRC. The epidermal growth factor (EGF) receptor (EGFR) signaling pathway is frequently dysregulated in CRC. Our earlier research showed that the procyanidin dimers of epicatechin gallate (ECG) and epigallocatechin gallate (EGCG), through their interaction with lipid rafts, inhibit the EGFR signaling pathway and decrease CRC cell growth. The process of cancer cell invasion and metastasis involves matrix metalloproteinases (MMPs), which are partially EGFR-regulated. This study investigated whether ECG and EGCG dimers can inhibit EGF-induced CRC cell invasion by suppressing the redox-regulated activation of the EGFR/MMPs pathway. Both dimers mitigated EGF-induced cell invasion and the associated increase of MMP-2/9 expression and activity in different CRC cell lines. In Caco-2 cells, both dimers inhibited the activation of the EGFR and downstream of NF-κB, ERK1/2 and Akt, which was associated with decreased MMP-2/9 transcription. EGF induced a rapid NOX1-dependent oxidant increase, which was diminished by both ECG and EGCG dimers and NOX inhibitors (apocynin, Vas-2870, DPI). Both dimers inhibited NOX1 gene expression, as well as NOX1 activity with evidence of direct binding to NOX1. Both dimers, all NOX chemical inhibitors and NOX1 silencing inhibited EGF-mediated activation of the EGFR signaling pathway and the increased MMP-2/9 mRNA levels and activity. Pointing to the relevance of NOX1 on ECG and EGCG dimer effects on CRC invasiveness, silencing of NOX1 also inhibited EGF-stimulated Caco-2 cell invasion. In summary, ECG and EGCG dimers can act inhibiting CRC cell invasion/metastasis both, by downregulating MMP-2 and MMP-9 expression via a NOX1/EGFR-dependent mechanism, and through a direct inhibitory effect on MMPs enzyme activity.

The potential chemo-preventive roles of Malus domestica against the risk of colorectal cancer: A suggestive insight into clinical application

Biologically active compounds in fruit-derived ingredients, particularly phytochemicals, have significant potential to modulate and mitigate many pathological processes in the development of disease conditions, including cancer. Colorectal cancer (CRC) remains a major public health issue. Nonetheless, prevention is an important step in lowering the rate of mortality from this cancer. Currently, the link between apple consumption and improved health is becoming remarkably evident and is reported to be beneficial for human health. Phytochemicals, such as flavonoids and other polyphenol compounds extensively available in apple fruits, have well-known positive effects on health outcomes and the potential to combat and prevent the development of CRC, including antioxidant, anti-proliferative, and anti-carcinogenic effects. This review describes the bioactive compounds derived from apple fruits, particularly the polyphenols and flavonoids, their proposed mechanisms responsible for their bioactive properties and health-promoting attributes that could provide potential chemo-preventive effects against the risk of CRC development. The conclusion of the review provides insights into the potential effects of apple-derived bioactive compounds and proposes the need for more clinical studies in large trials for future strategies regarding the valuable effects of apple phytochemicals, which might be therapeutic candidates in the campaign against CRC.

Cherry Polyphenol Extract Ameliorated Dextran Sodium Sulfate-Induced Ulcerative Colitis in Mice by Suppressing Wnt/β-Catenin Signaling Pathway

Ulcerative colitis (UC) is a chronic and nonspecific inflammatory disease of the colon and rectum, and its etiology remains obscure. Cherry polyphenols showed potential health-promoting effects. However, both the protective effect and mechanism of cherry polyphenols on UC are still unclear. This study aimed to investigate the potential role of the free polyphenol extract of cherry in alleviating UC and its possible mechanism of action. Our study revealed that the free polyphenol extract of cherry management significantly alleviated UC symptoms, such as weight loss, colon shortening, the thickening of colonic mucous layer, etc. The free polyphenol extract of cherry treatment also introduced a significant reduction in levels of malondialdehyde (MDA), myeloperoxidase (MPO) and nitric oxide (NO), while causing a significant elevation in levels of catalase (CAT), glutathione (GSH-Px), superoxide dismutase (SOD), as well as the downregulation of pro-inflammatory cytokines. This indicated that such positive effects were performed through reducing oxidative damage or in a cytokine-specific manner. The immunofluorescence analysis of ZO-1 and occludin proteins declared that the free polyphenol extract of cherry had the potential to prompt intestinal barrier function. The reduced expression levels of β-catenin, c-myc, cyclin D1 and GSK-3β suggested that the cherry extract performed its positive effect on UC by suppressing the Wnt/β-ctenin pathway. This finding may pave the way into further understanding the mechanism of cherry polyphenols ameliorating ulcerative colitis.

A Comprehensive Overview of Colon Cancer- A Grim Reaper of the 21st Century

A few decades ago, the incidence of colorectal cancer (CRC) was low and is now the fourth in the list of deadly cancers producing nearly a million deaths annually. A population that is aging along with risk factors such as smoking, obesity, sedentary lifestyle with little or no physical activity, and non-healthy food habits of developed countries can increase the risk of colorectal cancer. The balance in gut microbiota and the metabolites produced during bacterial fermentation within the host plays a significant role in regulating intestinal diseases as well as colorectal cancer development. Recent progress in the understanding of illness resulted in multiple treatment options such as surgery, radiation, and chemotherapy, including targeted therapy and multitherapies. The treatment plan for CRC depends on the location, stage and grade of cancer as well as genomic biomarker tests. Despite all the advancements made in the genetic and molecular aspects of the disease, the knowledge seems inadequate as the drug action as well as the wide variation in drug response did not appear strongly correlated with the individual molecular and genetic characteristics, which suggests the requirement of comprehensive molecular understanding of this complex heterogeneous disease. Furthermore, multitherapies or a broad spectrum approach, which is an amalgamation of the various promising as well as effective therapeutic strategies that can tackle heterogeneity and act on several targets of the disease, need to be validated in clinical studies. The latest treatment options have significantly increased the survival of up to three years in the case of advanced disease. The fact that colorectal cancer is developed from a polypoid precursor, as well as the symptoms of the disease that occur at an advanced stage, underlines how screening programs can help early detection and decrease mortality as well as morbidity from CRC.

Hexameric procyanidins inhibit colorectal cancer cell growth through both redox and non-redox regulation of the epidermal growth factor signaling pathway

Dietary proanthocyanidins (PAC) consumption is associated with a decreased risk for colorectal cancer (CRC). Dysregulation of the epidermal growth factor (EGF) receptor (EGFR) signaling pathway is frequent in human cancers, including CRC. We previously showed that hexameric PAC (Hex) exert anti-proliferative and pro-apoptotic actions in human CRC cells. This work investigated if Hex could exert anti-CRC effects through its capacity to regulate the EGFR pathway. In proliferating Caco-2 cells, Hex acted attenuating EGF-induced EGFR dimerization and NADPH oxidase-dependent phosphorylation at Tyr 1068, decreasing EGFR location at lipid rafts, and inhibiting the downstream activation of pro-proliferative and anti-apoptotic pathways, i.e. Raf/MEK/ERK1/2 and PI3K/Akt. Hex also promoted EGFR internalization both in the absence and presence of EGF. While Hex decreased EGFR phosphorylation at Tyr 1068, it increased EGFR Tyr 1045 phosphorylation. The latter provides a docking site for the ubiquitin ligase c-Cbl and promotes EGFR degradation by lysosomes. Importantly, Hex acted synergistically with the EGFR-targeted chemotherapeutic drug Erlotinib, both in their capacity to decrease EGFR phosphorylation and inhibit cell growth. Thus, dietary PAC could exert anti-CRC actions by modulating, through both redox- and non-redox-regulated mechanisms, the EGFR pro-oncogenic signaling pathway. Additionally, Hex could also potentiate the actions of EGFR-targeted drugs.

Curcumin - A Novel Therapeutic Agent in the Prevention of Colorectal Cancer

Background:

Colorectal cancer is the third important cause of cancer-associated deaths across the world. Hence, there is an urgent need for understanding the complete mechanism associated with colorectal cancer, which in turn can be utilized toward early detection as well as the treatment of colorectal cancer in humans. Though colorectal cancer is a complex process and chemotherapy is the first step toward the treatment of colorectal cancer, recently several studies suggested that dietary phytochemicals may also aid significantly in reducing colorectal cancer risk in human. However, only few phytochemicals, specifically curcumin derived from the rhizomes of Curcuma longa, have better chemotherapeutic property, which might be because of its ability to regulate the activity of key factors associated with the initiation, promotion, as well as progression of tumors.

Objectives:

In the present review, the authors made an attempt to summarize the physiochemical properties of curcumin, which in turn prevent colorectal cancer via regulating numerous cell signaling as well as genetic pathways.

Conclusions:

Accumulated evidence suggested that curcumin suppresses tumour/colon cancer in various ways, (a) restricting cell cycle progression, or stimulating apoptosis, (b) restricting angiogenesis, anti-apoptotic proteins expression, cell survival signaling pathways & their cross-communication and (c) regulating immune responses. The information discussed in the present review will be useful in the drug discovery process as well as the treatment and prevention of colorectal cancer in humans.

Polyphenols: Immunomodulatory and Therapeutic Implication in Colorectal Cancer

Polyphenolic compounds, widely present in fruits, vegetables, and cereals, have potential benefits for human health and are protective agents against the development of chronic/degenerative diseases including cancer. More recently these bioactive molecules have been gaining great interest as anti-inflammatory and immunomodulatory agents, mainly in neoplasia where the pro-inflammatory context might promote carcinogenesis. Colorectal cancer (CRC) is considered a major public healthy issue, a leading cause of cancer mortality and morbidity worldwide. Epidemiological, pre-clinical and clinical investigations have consistently highlighted important relationships between large bowel inflammation, gut microbiota (GM), and colon carcinogenesis. Many experimental studies and clinical evidence suggest that polyphenols have a relevant role in CRC chemoprevention, exhibit cytotoxic capability vs. CRC cells and induce increased sensitization to chemo/radiotherapies. These effects are most likely related to the immunomodulatory properties of polyphenols able to modulate cytokine and chemokine production and activation of immune cells. In this review we summarize recent advancements on immunomodulatory activities of polyphenols and their ability to counteract the inflammatory tumor microenvironment. We focus on potential role of natural polyphenols in increasing the cell sensitivity to colon cancer therapies, highlighting the polyphenol-based combined treatments as innovative immunomodulatory strategies to inhibit the growth of CRC.

Dietary phytochemicals in colorectal cancer prevention and treatment: A focus on the molecular mechanisms involved

Worldwide, colorectal cancer (CRC) remains a major cancer type and leading cause of death. Unfortunately, current medical treatments are not sufficient due to lack of effective therapy, adverse side effects, chemoresistance and disease recurrence. In recent decades, epidemiologic observations have highlighted the association between the ingestion of several phytochemical-enriched foods and nutrients and the lower risk of CRC. According to preclinical studies, dietary phytochemicals exert chemopreventive effects on CRC by regulating different markers and signaling pathways; additionally, the gut microbiota plays a role as vital effector in CRC onset and progression, therefore, any dietary alterations in it may affect CRC occurrence. A high number of studies have displayed a key role of growth factors and their signaling pathways in the pathogenesis of CRC. Indeed, the efficiency of dietary phytochemicals to modulate carcinogenic processes through the alteration of different molecular targets, such as Wnt/β-catenin, PI3K/Akt/mTOR, MAPK (p38, JNK and Erk1/2), EGFR/Kras/Braf, TGF-β/Smad2/3, STAT1-STAT3, NF-кB, Nrf2 and cyclin-CDK complexes, has been proven, whereby many of these targets also represent the backbone of modern drug discovery programs. Furthermore, epigenetic analysis showed modified or reversed aberrant epigenetic changes exerted by dietary phytochemicals that led to possible CRC prevention or treatment. Therefore, our aim is to discuss the effects of some common dietary phytochemicals that might be useful in CRC as preventive or therapeutic agents. This review will provide new guidance for research, in order to identify the most studied phytochemicals, their occurrence in foods and to evaluate the therapeutic potential of dietary phytochemicals for the prevention or treatment of CRC by targeting several genes and signaling pathways, as well as epigenetic modifications. In addition, the results obtained by recent investigations aimed at improving the production of these phytochemicals in genetically modified plants have been reported. Overall, clinical data on phytochemicals against CRC are still not sufficient and therefore the preventive impacts of dietary phytochemicals on CRC development deserve further research so as to provide additional insights for human prospective studies.

A novel nutritional intervention improves lung function in overweight/obese adolescents with poorly controlled asthma: the Supplemental Nutrition in Asthma Control (SNAC) pilot study

Asthma in the obese is often severe, difficult to treat, and characterized by less eosinophilic inflammation than asthma in the nonobese. Obesity-associated metabolic dysregulation may be a causal factor. We previously reported that a nutrient- and fiber-dense bar [Children's Hospital Oakland Research Institute (CHORI)-bar], which was designed to fill gaps in poor diets, improved metabolism in healthy overweight/obese (OW/OB) adults. In this pilot trial, OW/OB adolescents with poorly controlled asthma were randomized to weekly nutrition/exercise classes with or without twice-daily CHORI-bar consumption. Intent-to-treat analysis did not indicate CHORI-bar-specific effects. However, restricting the analysis to participants with acceptable compliance and a relatively low fraction of exhaled nitric oxide (FENO; <50/ ppb, a surrogate for noneosinophilic asthma; study participants: CHORI-bar, n = 16; controls, n = 15) indicated that CHORI-bar-specific, significant improvements in lung function (forced vital capacity, percent-predicted forced expiratory volume in 1 s, and percent-predicted forced expiratory flow between 25 and 75% of forced vital capacity), primarily in participants with low chronic inflammation (high-sensitivity C-reactive protein <1.5 mg/L). (We previously observed that chronic inflammation blunted CHORI-bar-induced metabolic improvements in healthy OW/OB adults.) Lung function improvement occurred without weight loss and was independent of improvements in metabolic and anthropometric end points and questionnaire-based measures of asthma control and quality of life. This study suggests that a nutritional intervention can improve lung function in OW/OB adolescents with asthma and relatively low FENO without requiring major changes in dietary habits, lifestyle, or weight loss and that this effect is blunted by chronic inflammation.-Bseikri, M., McCann, J. C., Lal, A., Fong, E., Graves, K., Goldrich, A., Block, D., Gildengoren, G. L., Mietus-Snyder, M., Shigenaga, M., Suh, J., Hardy, K., Ames, B. N. A novel nutritional intervention improves lung function in overweight/obese adolescents with poorly controlled asthma: the Supplemental Nutrition in Asthma Control (SNAC) pilot study.

Naringenin (4,5,7-trihydroxyflavanone) suppresses the development of precancerous lesions via controlling hyperproliferation and inflammation in the colon of Wistar rats

Colon cancer is a world-wide health problem and one of the most dangerous type of cancer, affecting both men and women. Naringenin (4, 5, 7-trihydroxyflavanone) is one of the major flavone glycoside present in citrus fruits. Naringenin has long been used in Chinese's traditional medicine because of its exceptional pharmacological properties and non-toxic nature. In the present study, we investigated the chemopreventive potential of Naringenin against 1,2-dimethyhydrazine (DMH)-induced precancerous lesions, that is, aberrant crypt foci (ACF) and mucin depleted foci (MDF), and its role in regulating the oxidative stress, inflammation and hyperproliferation, in the colon of Wistar rats. Animals were divided into five groups. In groups 3-5, Naringenin was administered at the dose of 50 mg/kg b. wt. orally while in groups 2-4, DMH was administered subcutaneously in the groin at the dose of 20 mg/kg b. wt. once a week for first 5 weeks and animals were euthanized after 10 weeks. Administration of Naringenin ameliorated the development of DMH-induced lipid peroxidation, ROS formation, precancerous lesions (ACF and MDF) and it also reduced the infiltration of mast cells, suppressed the immunostaining of NF-κB-p65, COX-2, i-NOS PCNA and Ki 67 Naringenin treatment significantly attenuated the level of TNF-α and it also prevented the depletion of the mucous layer. Our findings suggest that Naringenin has strong chemopreventive potential against DMH-induced colon carcinogenesis but further studies are warranted to elucidate the precise mechanism of action of Naringenin.

Ultrastructural changes induced by Solanum incanum aqueous extract on HCT 116 colon cancer cells

Medicinal plants have recently gained increasing scientific interest as an important source of molecules with different therapeutic potentials. Accordingly, the present study was carried out to investigate ultrastructural changes induced by the aqueous extract of Solanum incanum (SI) fruit on human colorectal carcinoma cell line (HCT 116 cells). Examination of SI-treated HCT 116 cells with transmission electron microscopy (TEM) demonstrated numerous ultrastructural changes in the form of loss of the surface microvilli, mitochondrial damage and dilatation of cristae, and formation of autophagic vacuoles and increasing numbers of lipid droplets. Also, majority of the treated cells showed nuclear shrinkage with chromatin condensation and nucleolar changes. Moreover, some cells showed focal areas of cytoplasmic degeneration associating with formation of myelin figures and fatty globules. In conclusion, TEM was able to verify cytotoxicity of SI aqueous extract against HCT 116 colon cancer cells.

Co-Delivery of Curcumin and Chrysin by Polymeric Nanoparticles Inhibit Synergistically Growth and hTERT Gene Expression in Human Colorectal Cancer Cells

Nanoparticle (NP)-based combinational chemotherapy has been proposed as a potent approach for improving intracellular drug concentrations and attaining synergistic effects in colorectal cancer therapy. Here, two well-known herbal substances, Curcumin (Cur) and Chrysin (Chr), were co-encapsulated in PEGylated PLGA NPs and investigated their synergistic inhibitory effect against Caco-2 cancer cells. Characterization of nanoformulated drugs was determined using DLS, FTIR, TEM, and SEM. Drug release study was performed using dialysis method. MTT and real-time PCR assays were applied to evaluate the cytotoxic effects of free and nano-encapsulated drugs on expression level of hTERT in Caco-2 cells. The results showed that free drugs and nano-formulations exhibited a dose-dependent cytotoxicity against Caco-2 cells and especially, Cur-Chr-PLGA/PEG NPs had more synergistic antiproliferative effect and significantly arrested the growth of cancer cells than the other groups (P < 0.05). Real-time PCR results revealed that Cur, Chr, and combination of Cur-Chr in free and encapsulated forms inhibited hTERT gene expression. Also, it was found that Cur-Chr-PLGA/PEG NPs than free combination forms could further decline hTERT expression in all concentration (P < 0.05). In summary, our study represents the first report of nano-combinational application of the natural herbal substances with a one-step fabricated codelivery system for effective colorectal cancer combinational chemotherapy.

Scientific Evidence of Rice By-Products for Cancer Prevention: Chemopreventive Properties of Waste Products from Rice Milling on Carcinogenesis In Vitro and In Vivo

Cancer is a significant global health concern affecting men and women worldwide. Although current chemopreventive drugs could inhibit the growth of cancer cells, they exert many adverse side effects. Dietary factor plays a crucial role in the management of cancers and has drawn the attention of researchers to be used as an option to combat this disease. Both in vitro and in vivo studies showed that rice and its by-products display encouraging results in the prevention of this disease. The mechanism of anticancer effect is suggested partly through potentiation of bioactive compounds like vitamin E, phytic acid, γ-aminobutyric acid (GABA), γ-oryzanol, and phenolics. Nevertheless, the bioactivity of rice and its by-products is still incompletely understood. In this review, we present the findings from a preclinical study both in in vitro and in animal experiments on the promising role of rice by-products with focus on cancer prevention.

Synergic chemoprevention with dietary carbohydrate restriction and supplementation of AMPK-activating phytochemicals: the role of SIRT1

Calorie restriction or a low-carbohydrate diet (LCD) can increase life span in normal cells while inhibiting carcinogenesis. Various phytochemicals also have calorie restriction-mimetic anticancer properties. We investigated whether an isocaloric carbohydrate-restriction diet and AMP-activated protein kinase (AMPK)-activating phytochemicals induce synergic tumor suppression. We used a mixture of AMPK-activating phytochemical extracts including curcumin, quercetin, catechins, and resveratrol. Survival analysis was carried out in a B16F10 melanoma model fed a control diet (62.14% kcal carbohydrate, 24.65% kcal protein and 13.2% kcal fat), a control diet with multiple phytochemicals (MP), LCD (16.5, 55.2, and 28.3% kcal, respectively), LCD with multiple phytochemicals (LCDmp), a moderate-carbohydrate diet (MCD, 31.9, 62.4, and 5.7% kcal, respectively), or MCD with phytochemicals (MCDmp). Compared with the control group, MP, LCD, or MCD intervention did not produce survival benefit, but LCDmp (22.80±1.58 vs. 28.00±1.64 days, P=0.040) and MCDmp (23.80±1.08 vs. 30.13±2.29 days, P=0.008) increased the median survival time significantly. Suppression of the IGF-1R/PI3K/Akt/mTOR signaling, activation of the AMPK/SIRT1/LKB1pathway, and NF-κB suppression were the critical tumor-suppression mechanisms. In addition, SIRT1 suppressed proliferation of the B16F10 and A375SM cells under a low-glucose condition. Alterations in histone methylation within Pten and FoxO3a were observed after the MCDmp intervention. In the transgenic liver cancer model developed by hydrodynamic transfection of the HrasG12V and shp53, MCDmp and LCDmp interventions induced significant cancer-prevention effects. Microarray analysis showed that PPARα increased with decreased IL-6 and NF-κB within the hepatocytes after an MCDmp intervention. In conclusion, an isocaloric carbohydrate-restriction diet and natural AMPK-activating agents induce synergistic anticancer effects. SIRT1 acts as a tumor suppressor under a low-glucose condition.

Water extract of brewers' rice induces apoptosis in human colorectal cancer cells via activation of caspase-3 and caspase-8 and downregulates the Wnt/β-catenin downstream signaling pathway in brewers' rice-treated rats with azoxymethane-induced colon carcinogenesis

BACKGROUND

Brewers' rice, is locally known as temukut, is a mixture of broken rice, rice bran, and rice germ. The current study is an extension of our previous work, which demonstrated that water extract of brewers' rice (WBR) induced apoptosis in human colorectal cancer (HT-29) cells. We also identified that brewers' rice was effective in reducing the tumor incidence and multiplicity in azoxymethane (AOM)-injected colon cancer rats. Our present study was designed to identify whether WBR confers an inhibitory effect via the regulation of upstream components in the Wnt signaling pathway in HT-29 cells. To further determine whether the in vitro mechanisms of action observed in the HT-29 cells inhibit the downstream signaling target of the Wnt/β-catenin pathway, we evaluated the mechanistic action of brewers' rice in regulating the expressions and key protein markers during colon carcinogenesis in male Sprague-Dawley rats.

METHODS

The mRNA levels of several upstream-related genes in the Wnt signaling pathway in HT-29 cells treated with WBR were determined by quantitative real-time PCR analyses. Caspase-3 and -8 were evaluated using a colorimetric assay. Male Sprague-Dawley rats were administered two intraperitoneal injections of AOM in saline (15 mg/kg body weight) over a two-week period and received with 10, 20, and 40% (w/w) brewers' rice. The expressions and protein levels of cyclin D1 and c-myc were evaluated by immunohistochemical staining and western blotting, respectively.

RESULTS

The overall analyses revealed that the treatment of HT-29 cells with WBR inhibited Wnt signaling activity through upregulation of the casein kinase 1 (CK1) and adenomatous polyposis coli (APC) mRNA levels. We discovered that the treatment of HT-29 cells with WBR resulted in the induction of apoptosis by the significant activation of caspase-3 and -8 activities compared with the control (P < 0.05). In vivo analyses indicated that brewers' rice diminished the β-catenin, cyclin D1, and c-myc protein levels.

CONCLUSIONS

We provide evidence that brewers' rice can induce apoptosis and inhibit the proliferation of HT-29 cells through regulation of caspase-dependent pathways and inhibit the Wnt/β-catenin downstream signaling pathway in vivo. We suggest that brewers' rice may be a useful dietary agent for colorectal cancer.

Anticarcinogenic Effect of Corn Tortilla Against 1,2-Dimethylhydrazine (DMH)-Induced Colon Carcinogenesis in Sprague-Dawley Rats

Mexico has the highest per capita consumption of corn in the world, which is consumed mainly as tortilla. However, only a few in vivo studies have demonstrated the anticarcinogenic potential of some maize components against colon cancer, but not as a whole food product. Therefore, our objective was to evaluate the protective effect of corn tortillas against the development of colon cancer. First, blue, red, yellow and white corn grains were lime-cooked and processed to elaborate tortillas. Then, tortillas were administered into the diet (27% w/w) to male Sprague-Dawley rats induced with the colon carcinogen 1,2-dimethylhydrazine (DMH). Our results indicated that consumption of tortillas, particularly from white and blue corns, significantly decreased adenocarcinoma incidence (up to 77.5%) and mean number compared to DMH-treated animals. In addition, an inhibition of β-glucuronidase activity, and induction of detoxifying enzymes in liver and colon, as well as a decrease in the expression of the two most important proliferative proteins (K-ras and β-catenin) involved in colon carcinogenesis, were also observed. These results highlight some of the molecular mechanisms related to the chemopreventive effect of tortillas, thus indicating that corn products retain their biological properties even after nixtamalization and tortilla processing.

A multicomponent nutrient bar promotes weight loss and improves dyslipidemia and insulin resistance in the overweight/obese: chronic inflammation blunts these improvements

This study determined if twice-daily consumption of a nutrient-dense bar intended to fill gaps in Western diets, without other dietary/lifestyle requirements, favorably shifted metabolic/anthropometric indicators of dysregulation in a healthy direction. Three 8-wk clinical trials in 43 healthy lean and overweight/obese (OW/OB) adults, who served as their own controls, were pooled for analysis. In less inflamed OW/OB [high-sensitivity C-reactive protein (hsCRP) <1.5], statistically significant decreases occurred in weight (-1.1 ± 0.5 kg), waist circumference (-3.1 ± 1.4 cm), diastolic blood pressure (-4.1 ± 1.6 mmHg), heart rate [HR; -4.0 ± 1.7 beats per minute (bpm)], triglycerides (-72 ± 38.2 mg/dl), insulin resistance (homeostatic model of insulin resistance) (-0.72 ± 0.3), and insulin (-2.8 ± 1.3 mU/L); an increase in HDL-2b (+303 ± 116 nM) and realignment of LDL lipid subfractions toward a less atherogenic profile [decreased small LDL IIIb (-44 ± 23.5 nM), LDL IIIa (-99 ± 43.7 nM), and increased large LDL I (+66 ± 28.0 nM)]. In the more inflamed OW/OB (hsCRP >1.5), inflammation was reduced at 2 wk (-0.66 mg/L), and HR at 8 wk (-3.4 ± 1.3 bpm). The large HDL subfraction (10.5-14.5 nm) increased at 8 wk (+346 ± 126 nM). Metabolic improvements were also observed in lean participants. Thus, favorable changes in measures of cardiovascular health, insulin resistance, inflammation, and obesity were initiated within 8 wk in the OW/OB by replacing deficiencies in Western diets without requiring other dietary or lifestyle modifications; chronic inflammation blunted most improvements.

Brewers' rice induces apoptosis in azoxymethane-induced colon carcinogenesis in rats via suppression of cell proliferation and the Wnt signaling pathway

Background

Brewers’ rice is locally known as temukut, is a byproduct of the rice milling process, and consists of broken rice, rice bran, and rice germ. Unlike rice bran, the health benefit of brewers’ rice has yet to be fully studied. Our present study aimed to identify the chemopreventive potential of brewers’ rice with colonic tumor formation and to examine further the mechanistic action of brewers’ rice during colon carcinogenesis.

Methods

Male Sprague–Dawley rats were randomly divided into five groups: (G1) normal; (G2) azoxymethane (AOM) alone; and (G3), (G4), and (G5), which were AOM fed with 10%, 20%, and 40% (w/w) of brewers’ rice, respectively. Rats in group 2 to 5 were injected intraperitoneally with AOM (15 mg/kg body weight) once weekly for two weeks. Colon tumor incidence and multiplicity was assessed by hematoxylin and eosin (H&E) staining. The expression of β-catenin, cyclooxygenase-2 (COX-2), and Ki-67 was evaluated by immunohistochemical staining. The apoptosis-inducing activity was analyzed using a TUNEL assay. The data were analyzed using a one-way analysis of variance (ANOVA) with P-value<0.05 was considered significant.

Results

Overall analyses revealed that brewers’ rice reduced colon tumor incidence and multiplicity. The results from immunohistochemistry analysis also showed that brewers’ rice decreased the expression of β-catenin, COX-2, and Ki-67 in a dose-dependent manner. Furthermore, TUNEL analysis demonstrated that administration of brewers’ rice in AOM-induced rat colorectal cancer resulted in a dose-dependent increase in cell apoptosis.

Conclusions

Taken together, our data suggested that brewers’ rice can inhibit cell proliferation, induce apoptosis, and suppress COX-2 and β-catenin expression via the Wnt signaling pathway and holds great promise in the field of chemoprevention as a dietary agent.

Nutraceuticals as potential therapeutic agents for colon cancer: a review

Colon cancer is a world-wide health problem and the second-most dangerous type of cancer, affecting both men and women. The modern diet and lifestyles, with high meat consumption and excessive alcohol use, along with limited physical activity has led to an increasing mortality rate for colon cancer worldwide. As a result, there is a need to develop novel and environmentally benign drug therapies for colon cancer. Currently, nutraceuticals play an increasingly important role in the treatment of various chronic diseases such as colon cancer, diabetes and Alzheimer׳s disease. Nutraceuticals are derived from various natural sources such as medicinal plants, marine organisms, vegetables and fruits. Nutraceuticals have shown the potential to reduce the risk of colon cancer and slow its progression. These dietary substances target different molecular aspects of colon cancer development. Accordingly, this review briefly discusses the medicinal importance of nutraceuticals and their ability to reduce the risk of colorectal carcinogenesis.

Rice varietal differences in bioactive bran components for inhibition of colorectal cancer cell growth

Rice bran chemical profiles differ across rice varieties and have not yet been analysed for differential chemopreventive bioactivity. A diverse panel of seven rice bran varieties was analysed for growth inhibition of human colorectal cancer (CRC) cells. Inhibition varied from 0% to 99%, depending on the variety of bran used. Across varieties, total lipid content ranged 5-16%, individual fatty acids had 1.4- to 1.9-fold differences, vitamin E isoforms (α-, γ-, δ-tocotrienols, and tocopherols) showed 1.3- to 15.2-fold differences, and differences in γ-oryzanol and total phenolics ranged between 100-275ng/mg and 57-146ngGAE/mg, respectively. Spearman correlation analysis was used to identify bioactive compounds implicated in CRC cell growth inhibitory activity. Total phenolics and γ-tocotrienol were positively correlated with reduced CRC cell growth (p<0.05). Stoichiometric variation in rice bran components and differential effects on CRC viability merit further evaluation elucidate their role in dietary CRC chemoprevention.

AMPK synergizes with the combined treatment of 1'-acetoxychavicol acetate and sodium butyrate to upregulate phase II detoxifying enzyme activities

SCOPE

Phase II enzymes play important roles in detoxifying xenobiotics. We previously reported that both 1'-acetoxychavicol acetate (ACA) and sodium butyrate individually increased phase II enzyme activities. Here, we determined the combined action of ACA and sodium butyrate on phase II enzyme activities in intestinal epithelial cells (IEC 6).

METHODS AND RESULTS

ACA and sodium butyrate synergistically increased phase II enzyme activities. Protein levels of intranuclear transcription factor NF-E2-related factor 2 (Nrf2) were increased by ACA or sodium butyrate treatment, but treatment with both did not produce a synergistic effect. Intranuclear p53 protein levels were increased by ACA but decreased by sodium butyrate alone or combined treatment with ACA and sodium butyrate. In contrast, p53 acetylation was promoted by sodium butyrate and the ACA and sodium butyrate combination. Inhibition of AMPK activity decreased phase II enzyme activities that were upregulated by treatment with ACA plus sodium butyrate or other phytochemicals, including kaempferol, quercetin, and epigallocatechin-3-gallate. Combined treatment with ACA and sodium butyrate increased phosphorylated AMPK levels.

CONCLUSION

These results suggest that ACA and sodium butyrate synergistically contribute to xenobiotics metabolism. The combined ACA and sodium butyrate treatment synergistically upregulated phase II enzyme activities through AMPK activation and p53 acetylation.

Nutritional agents with anti-inflammatory properties in chemoprevention of colorectal neoplasia

The strong link between inflammation and colorectal carcinogenesis provides the rationale for using anti-inflammatory agents for chemoprevention of colorectal cancer (CRC). Several naturally occurring substances with anti-inflammatory properties, used in a purified 'nutraceutical' form, including omega-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and polyphenols such as curcumin and resveratrol, have been demonstrated to have anti-CRC activity in preclinical models. As expected, these agents have an excellent safety and tolerability profile in Phase II clinical trials. Phase III randomized clinical trials of these naturally occurring substances are now beginning to be reported. The omega-3 polyunsaturated fatty acid EPA, in the free fatty acid (FFA) form, has been demonstrated to reduce adenomatous polyp number and size in patients with familial adenomatous polyposis (FAP), a finding which has prompted evaluation of this formulation of EPA for prevention of 'sporadic' colorectal neoplasia. Anti-inflammatory 'nutraceuticals' require further clinical evaluation in polyp prevention trials as they exhibit many of the characteristics of the ideal cancer chemoprevention agent, including safety, tolerability and patient acceptability.

Apple polyphenols extract (APE) improves colon damage in a rat model of colitis

BACKGROUND AND AIM

Searching for alternative therapies that are effective, safe and less expensive of those currently used for ulcerative colitis, we investigated the efficacy of a polyphenol extract from apple in rat colitis.

METHODS

Rats with trinitrobenzensulphonic acid-induced colitis were treated daily with rectal administration of apple polyphenols 10(-4) M for 14 days. COX-2, TNF-α, tissue transglutaminase and calpain in colon mucosa samples were assessed by reverse transcription-polymerase chain reaction and western blot analyses. To ascertain the role of tissue transglutaminase in mucosal healing, wounded rat fibroblasts were incubated with cystamine (a tissue transglutaminase activity inhibitor).

RESULTS

Colitis was associated with increased COX-2, TNF-α, calpain, and tissue transglutaminase mRNA. The protein expression of COX-2, TNF-α and calpain was increased whilst tissue transglutaminase was decreased. Apple extract treatment reduced the severity of colitis (p<0.05) and restored all the considered biomarkers at the baseline level. Apple polyphenols reduced the degradation of tissue transglutaminase protein occurring through calpain action. Apple polyphenols-treated wounded fibroblast recovered within 24h showing intense immunoreactivity for tissue transglutaminase.

CONCLUSION

The efficacy of apple extract is mediated by its effects on COX-2 and TNF-α. The unbalance between calpain and tissue transglutaminase may play a role in colonic damage and future therapeutic interventions in ulcerative colitis can target this mechanisms.

Coffee, colon function and colorectal cancer

For several years the physiological effects of coffee have been focused on its caffeine content, disregarding the hundreds of bioactive coffee components, such as polyphenols, melanoidins, carbohydrates, diterpenes, etc. These compounds may exert their protection against colorectal cancer (CRC), the third most common cancer worldwide. However, the amount and type of compounds ingested with the beverage may be highly different depending on the variety of coffee used, the roasting degree, the type of brewing method as well as the serving size. In this frame, this paper reviews the mechanisms by which coffee may influence the risk of CRC development focusing on espresso and filtered coffee, as well as on the components that totally or partially reach the colon i.e. polyphenols and dietary fiber, including melanoidins. In particular the effects of coffee on some colon conditions whose deregulation may lead to cancer, namely microbiota composition and lumen reducing environment, were considered. Taken together the discussed studies indicated that, due to their in vivo metabolism and composition, both coffee chlorogenic acids and dietary fiber, including melanoidins, may reduce CRC risk, increasing colon motility and antioxidant status. Further studies should finally assess whether the coffee benefits for colon are driven through a prebiotic effect.