A phase Ib study of the effects of black raspberries on rectal polyps in patients with familial adenomatous polyposis

Rubus Occidentalis and its bioactive compounds against cancer: From molecular mechanisms to translational advances

BACKGROUND

Cancer ranks as the second leading cause of death globally, imposing a significant public health burden. The rise in cancer resistance to current therapeutic agents underscores the potential role of phytotherapy. Black raspberry (BRB, Rubus Occidentalis) is a fruit rich in anthocyanins, ellagic acid, and ellagitannins. Accumulating evidence suggests that BRB exhibits promising anticancer effects, positioning it as a viable candidate for phytotherapy.

PURPOSE

This article aims to review the existing research on BRB regarding its role in cancer prevention and treatment. It further analyzes the effective components of BRB, their metabolic pathways, and the potential mechanisms underlying the fruit's anticancer effects.

METHODS

Ovid MEDLINE, EMBASE, Web of Science, and CENTRAL were searched through the terms of Black Raspberry, Raspberry, and Rubus Occidentali up to January 2023. Two reviewers performed the study selection by screening the title and abstract. Full texts of potentially eligible studies were retrieved to access the details.

RESULTS

Out of the 767 articles assessed, 73 papers met the inclusion criteria. Among them, 63 papers investigated the anticancer mechanisms, while 10 conducted clinical trials focusing on cancer treatment or prevention. BRB was found to influence multiple cancer hallmarks by targeting various pathways. Decomposition of free radicals and regulation of estrogen metabolism, BRB can reduce DNA damage caused by reactive oxygen species. BRB can also enhance the function of nucleotide excision repair to repair DNA lesions. Through regulation of epigenetics, BRB can enhance the expression of tumor suppressor genes, inducing cell cycle arrest, and promoting apoptosis and pyroptosis. BRB can reduce the energy and nutrients supply to the cancer nest by inhibiting glycolysis and reducing angiogenesis. The immune and inflammatory microenvironment surrounding cancer cells can also be ameliorated by BRB, inhibiting cancer initiation and progression. However, the limited bioavailability of BRB diminishes its anticancer efficacy. Notably, topical applications of BRB, such as gels and suppositories, have demonstrated significant clinical benefits.

CONCLUSION

BRB inhibits cancer initiation, progression, and metastasis through diverse anticancer mechanisms while exhibiting minimal side effects. Given its potential, BRB emerges as a promising phototherapeutic agent for cancer treatment.

Green Cancer Prevention and Beyond

The concept of green chemoprevention was introduced in 2012 by Drs. Jed Fahey and Thomas Kensler as whole-plant foods and/or extract-based interventions demonstrating cancer prevention activity. Refining concepts and research demonstrating proof-of-principle approaches are highlighted within this review. Early approaches included extensively investigated whole foods, including broccoli sprouts and black raspberries showing dose-responsive effects across a range of activities in both animals and humans with minimal or no apparent toxicity. A recent randomized crossover trial evaluating the detoxification of tobacco carcinogens by a broccoli seed and sprout extract in the high-risk cohort of current smokers highlights the use of a dietary supplement as a potential next-generation green chemoprevention or green cancer prevention approach. Challenges are addressed, including the selection of dose, duration and mode of delivery, choice of control group, and standardization of the plant food or extract. Identification and characterization of molecular targets and careful selection of high-risk cohorts for study are additional important considerations when designing studies. Goals for precision green cancer prevention include acquiring robust evidence from carefully controlled human studies linking plant foods, extracts, and compounds to modulation of targets for cancer risk reduction in individual cancer types.

Black raspberry-mediated metabolic changes in patients with familial adenomatous polyposis associated with rectal polyp regression

Familial adenomatous polyposis (FAP) patients face an almost certain 100% risk of developing colorectal cancer, necessitating prophylactic colectomy to prevent disease progression. A crucial goal is to hinder this progression. In a recent clinical trial involving 14 FAP patients, half received 60 g of black raspberry (BRB) powder orally and BRB suppositories at bedtime, while the other half received only BRB suppositories at bedtime over 9 months. This intervention led to a notable reduction in rectal polyps for 11 patients, although 3 showed no response. In this study, we delved into the metabolic changes induced by BRBs in the same patient cohort. Employing mass spectrometry-based non-targeted metabolomics, we analyzed pre- and post-BRB urinary and plasma samples from the 11 responders. The results showed significant alterations in 23 urinary and 6 plasma metabolites, influencing various pathways including polyamine, glutathione metabolism, the tricarboxylic acid cycle, inositol metabolism, and benzoate production. BRBs notably elevated levels of several metabolites associated with these pathways, suggesting a potential mechanism through which BRBs facilitate rectal polyp regression in FAP patients by modulating multiple metabolic pathways. Notably, metabolites derived from BRB polyphenols were significantly increased post-BRB intervention, emphasizing the potential therapeutic value of BRBs in FAP management.

Berries vs. Disease: Revenge of the Phytochemicals

Secondary metabolites and phytochemicals in plant-based diets are known to possess properties that inhibit the development of several diseases including a variety of cancers of the aerodigestive tract. Berries are currently of high interest to researchers due to their high dietary source of phytochemicals. Black raspberries (BRB), Rubus occidentalis, are of special interest due to their rich and diverse composition of phytochemicals. In this review, we present the most up-to-date preclinical and clinical data involving berries and their phytochemicals in the chemoprevention of a variety of cancers and diseases. BRBs possess a variety of health benefits including anti-proliferative properties, anti-inflammatory activity, activation of pro-cell-death pathways, modulation of the immune response, microbiome modulation, reduction in oxidative stress, and many more. However, little has been done in both preclinical and clinical settings on the effects of BRB administration in combination with other cancer therapies currently available for patients. With the high potential for BRBs as chemopreventive agents, there is a need to investigate their potential in combination with other treatments to improve therapeutic efficacy.

Chemoprevention in hereditary digestive neoplasia: A comprehensive review

Hereditary syndromes, such as familial adenomatous polyposis (FAP), MUTYH polyposis or Lynch syndrome, are particularly predisposing to the development of colorectal cancer. These situations have necessitated the development of adapted prevention strategies based largely on reinforced endoscopic surveillance and the search for complementary prevention strategies. This is the case for chemoprevention, which is the long-term administration of chemical agents limiting carcinogenesis, used as primary or secondary prophylaxis. The aim of this review is to present the available literature and the latest advances in chemoprevention in patients with FAP or MUTYH and other polyposis as well as in patients with Lynch syndrome. The main conclusions of the few available guidelines in these situations are also discussed.

Secreted frizzled-related proteins: A promising therapeutic target for cancer therapy through Wnt signaling inhibition

The Wnt signaling system is a critical pathway that regulates embryonic development and adult homeostasis. Secreted frizzled-related proteins (SFRPs) are extracellular inhibitors of Wnt signaling that act by binding directly to Wnt ligands or Frizzled receptors. SFRPs can act as anti-Wnt agents and suppress cancer growth by blocking the action of Wnt ligands. However, SFRPs are often silenced by promoter methylation in cancer cells, resulting in hyperactivation of the Wnt pathway. Epigenetic modifiers can reverse this silencing and restore SFRPs expression. Despite the potential of SFRPs as a therapeutic target, the effects of SFRPs on tumor development remain unclear. Therefore, a review of the expression of various members of the SFRPs family in different cancers and their potential as therapeutic targets is warranted. This review aims to summarize the current knowledge of SFRPs in cancer, focusing on their expression patterns and their potential as novel therapeutic targets.

Dried Fruits, Nuts, and Cancer Risk and Survival: A Review of the Evidence and Future Research Directions

Dried fruits and nuts contain high amounts of nutrients and phytochemicals-all of which may have anticarcinogenic, anti-inflammatory, and antioxidant properties. This narrative review summarizes the evidence for dried fruits and nuts and cancer incidence, mortality, and survival and their potential anticancer properties. The evidence for dried fruits in cancer outcomes is limited, but existing studies have suggested an inverse relationship between total dried fruit consumption and cancer risk. A higher consumption of nuts has been associated with a reduced risk of several site-specific cancers in prospective cohort studies, including cancers of the colon, lung, and pancreas, with relative risks per 5 g/day increment equal to 0.75 (95% CI 0.60, 0.94), 0.97 (95% CI 0.95, 0.98), and 0.94 (95% CI 0.89, 0.99), respectively. A daily intake of total nuts of 28 g/day has also been associated with a 21% reduction in the rate of cancer mortality. There is also some evidence that frequent nut consumption is associated with improved survival outcomes among patients with colorectal, breast, and prostate cancer; however, further studies are needed. Future research directions include the investigation of additional cancer types, including rare types of cancer. For cancer prognosis, additional studies with pre- and postdiagnosis dietary assessment are warranted.

Modification of Diet to Reduce the Stemness and Tumorigenicity of Murine and Human Intestinal Cells

Scope

Black raspberries (BRBs) have colorectal cancer (CRC) chemo‐preventative effects. As CRC originates from an intestinal stem cell (ISC) this study has investigated the impact of BRBs on normal and mutant ISCs.

Methods and results

Mice with an inducible Apc^fl mutation in either the ISC (Lgr5CreER^T2) or intestinal crypt (AhCre/VillinCreER^T2) are fed a control or 10% BRB‐supplemented diet. This study uses immunohistochemistry, gene expression analysis, and organoid culture to evaluate the effect of BRBs on intestinal homeostasis. RNAscope is performed for ISC markers on CRC adjacent normal colonic tissue pre and post BRB intervention from patients. 10% BRB diet has no overt effect on murine intestinal homeostasis, despite a reduced stem cell number. Following Apc ISC deletion, BRB diet extends lifespan and reduces tumor area. In the AhCre model, BRB diet attenuates the “crypt‐progenitor” phenotype and reduces ISC marker gene expression. In ex vivo culture BRBs reduce the self‐renewal capacity of murine and human Apc deficient organoids. Finally, the study observes a reduction in ISC marker gene expression in adjacent normal crypts following introduction of BRBs to the human bowel.

Conclusion

BRBs play a role in CRC chemoprevention by protectively regulating the ISC compartment and further supports the use of BRBs in CRC prevention.

A Pilot Clinical Study to Investigate the Hypomethylating Properties of Freeze-dried Black Raspberries in Patients with Myelodysplastic Syndrome or Myeloproliferative Neoplasm

Myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) are bone marrow disorders characterized by cytopenias and progression to acute myeloid leukemia. Hypomethylating agents (HMAs) are Food and Drug Administration-approved therapies for MDS and MDS/MPN patients. HMAs have improved patients' survival and quality of life when compared with other therapies. Although HMAs are effective in MDS and MDS/MPN patients, they are associated with significant toxicities that place a large burden on patients. Our goal is to develop a safer and more effective HMA from natural products. We previously reported that black raspberries (BRBs) have hypomethylating effects in the colon, blood, spleen, and bone marrow of mice. In addition, BRBs exert hypomethylating effects in patients with colorectal cancer and familial adenomatous polyposis. In the current study, we conducted a pilot clinical trial to evaluate the hypomethylating effects of BRBs in patients with low-risk MDS or MDS/MPN. Peripheral blood mononuclear cells (PBMCs) were isolated before and after three months of BRB intervention. CD45+ cells were isolated from PBMCs for methylation analysis using a reduced-representation bisulfite sequencing assay. Each patient served as their own matched control, with their measurements assessed before intervention providing a baseline for post-intervention results. Clinically, our data showed that BRBs were well-tolerated with no side effects. When methylation data was combined, BRBs significantly affected methylation levels of 477 promoter regions. Pathway analysis suggests that BRB-induced intragenic hypomethylation drives leukocyte differentiation. A randomized, placebo-controlled clinical trial of BRB use in low-risk MDS or MDS/MPN patients is warranted.

Chemical Compounds of Berry-Derived Polyphenols and Their Effects on Gut Microbiota, Inflammation, and Cancer

Berry-derived polyphenols are bioactive compounds synthesized and secreted by several berry fruits. These polyphenols feature a diversity of chemical compounds, including phenolic acids and flavonoids. Here, we report the beneficial health effects of berry-derived polyphenols and their therapeutical application on gut-microbiota-related diseases, including inflammation and cancer. Pharmacokinetic investigations have confirmed the absorption, availability, and metabolism of berry-derived polyphenols. In vitro and in vivo tests, as well as clinical trials, showed that berry-derived polyphenols can positively modulate the gut microbiota, inhibiting inflammation and cancer development. Indeed, these compounds inhibit the growth of pathogenic bacteria and also promote beneficial bacteria. Moreover, berry-derived polyphenols exhibit therapeutic effects against different gut-microbiota-related disorders such as inflammation, cancer, and metabolic disorders. Moreover, these polyphenols can manage the inflammation via various mechanisms, in particular the inhibition of the transcriptional factor Nf-κB. Berry-derived polyphenols have also shown remarkable effects on different types of cancer, including colorectal, breast, esophageal, and prostate cancer. Moreover, certain metabolic disorders such as diabetes and atherosclerosis were also managed by berry-derived polyphenols through different mechanisms. These data showed that polyphenols from berries are a promising source of bioactive compounds capable of modulating the intestinal microbiota, and therefore managing cancer and associated metabolic diseases. However, further investigations should be carried out to determine the mechanisms of action of berry-derived polyphenol bioactive compounds to validate their safety and examinate their clinical uses.

Protocatechuic Acid, a Gut Bacterial Metabolite of Black Raspberries, Inhibits Adenoma Development and Alters Gut Microbiome Profiles in Apc Min/+ Mice

Administration of black raspberries (BRBs) and their anthocyanin metabolites, including protocatechuic acid (PCA), has been demonstrated to exert chemopreventive effects against colorectal cancer through alteration of innate immune cell trafficking, modulation of metabolic and inflammatory pathways, etc. Previous research has shown that the gut microbiome is important in the effectiveness of chemoprevention of colorectal cancer. This study aimed to assess the potency of PCA versus BRB dietary administration for colorectal cancer prevention using an Apc Min/+ mouse model and determine how bacterial profiles change in response to PCA and BRBs. A control AIN-76A diet supplemented with 5% BRBs, 500 ppm PCA, or 1,000 ppm PCA was administered to Apc Min/+ mice. Changes in incidence, polyp number, and polyp size regarding adenomas of the small intestine and colon were assessed after completion of the diet regimen. There were significant decreases in adenoma development by dietary administration of PCA and BRBs in the small intestine and the 5% BRB-supplemented diet in the colon. Pro-inflammatory bacterial profiles were replaced with anti-inflammatory bacteria in all treatments, with the greatest effects in the 5% BRB and 500 ppm PCA-supplemented diets accompanied by decreased COX-2 and prostaglandin E2 levels in colonic mucosa. We further showed that 500 ppm PCA, but not 1,000 ppm PCA, increased IFN-γ and SMAD4 levels in primary cultured human natural killer cells. These results suggest that both BRBs and a lower dose PCA can benefit colorectal cancer patients by inhibiting the growth and proliferation of adenomas and promoting a more favorable gut microbiome condition.

Chemoprevention Considerations in Patients with Hereditary Colorectal Cancer Syndromes

Secondary prevention of colorectal neoplasia with chemoprevention is long-studied area of research and clinical use in patients with the 2 most common hereditary colorectal cancer syndromes including Lynch syndrome and familial adenomatous polyposis. No medication is currently approved for use for the prevention of colorectal polyps or cancer in either the general population or individuals with the hereditary colorectal cancer syndromes. Emerging data in animal models and limited data in humans suggest vaccines may be the next breakthrough for neoplasia prevention in patients with hereditary colorectal cancer. Clinicians must acknowledge chemoprevention is an adjunct and does not supplant endoscopic surveillance.

Black raspberries attenuate colonic adenoma development in Apc Min mice: Relationship to hypomethylation of promoters and gene bodies

Recent studies have suggested that in addition to promoter region, DNA methylation in intragenic and intergenic regions also changes during physiological processes and disease. The current study showed that feeding of black raspberries (BRBs) to Apc^Min mice suppressed colon and intestinal tumors. MBDCap-seq suggested that dietary BRBs hypomethylated promoter, intragenic, and intergenic regions. Annotation of those regions highlighted genes in pathways involved in immune regulation, inflammatory signaling, production of nitric oxide and reactive oxygen species, and progression of colorectal cancer. BRB phytochemicals (e.g., ellagic acid, anthocyanins, oligosaccharides) and their gut bacterial metabolites (e.g., urolithin, protocatechuic acid, short-chain fatty acids) inhibited DNMT1 and DNMT3B activities in a cell-free assay. Our results suggest that BRBs’ hypomethylating activities result from the combined effects of multiple BRB phytochemicals and their gut bacterial metabolites. Because similar substances are found in many plant products, our results with BRBs might also apply to commonly consumed fruits and vegetables.

Review of Functional and Pharmacological Activities of Berries

Functional plant-based foods (such as fruits, vegetables, and berries) can improve health, have a preventive effect, and diminish the risk of different chronic diseases during in vivo and in vitro studies. Berries contain many phytochemicals, fibers, vitamins, and minerals. The primary phytochemicals in berry fruits are phenolic compounds including flavonoids (anthocyanins, flavonols, flavones, flavanols, flavanones, and isoflavonoids), tannins, and phenolic acids. Since berries have a high concentration of polyphenols, it is possible to use them for treating various diseases pharmacologically by acting on oxidative stress and inflammation, which are often the leading causes of diabetes, neurological, cardiovascular diseases, and cancer. This review examines commonly consumed berries: blackberries, blackcurrants, blueberries, cranberries, raspberries, black raspberries, and strawberries and their polyphenols as potential medicinal foods (due to the presence of pharmacologically active compounds) in the treatment of diabetes, cardiovascular problems, and other diseases. Moreover, much attention is paid to the bioavailability of active berry components. Hence, this comprehensive review shows that berries and their bioactive compounds possess medicinal properties and have therapeutic potential. Nevertheless, future clinical trials are required to study and improve the bioavailability of berries' phenolic compounds and extend the evidence that the active compounds of berries can be used as medicinal foods against various diseases.

Familial adenomatous polyposis and changes in the gut microbiota: New insights into colorectal cancer carcinogenesis

Patients with familial adenomatous polyposis (FAP), an autosomal dominant hereditary colorectal cancer syndrome, have a lifetime risk of developing cancer of nearly 100%. Recent studies have pointed out that the gut microbiota could play a crucial role in the development of colorectal adenomas and the consequent progression to colorectal cancer. Some gut bacteria, such as Fusobacterium nucleatum, Escherichia coli, Clostridium difficile, Peptostreptococcus, and enterotoxigenic Bacteroides fragilis, could be implicated in colorectal carcinogenesis through different mechanisms, including the maintenance of a chronic inflammatory state, production of bioactive tumorigenic metabolites, and DNA damage. Studies using the adenomatous polyposis coliMin/+ mouse model, which resembles FAP in most respects, have shown that specific changes in the intestinal microbial community could influence a multistep progression, the intestinal "adenoma-carcinoma sequence", which involves mucosal barrier injury, low-grade inflammation, activation of the Wnt pathway. Therefore, modulation of gut microbiota might represent a novel therapeutic target for patients with FAP. Administration of probiotics, prebiotics, antibiotics, and nonsteroidal anti-inflammatory drugs could potentially prevent the progression of the adenoma-carcinoma sequence in FAP. The aim of this review was to summarize the best available knowledge on the role of gut microbiota in colorectal carcinogenesis in patients with FAP.

Black Raspberries Suppress Colorectal Cancer by Enhancing Smad4 Expression in Colonic Epithelium and Natural Killer Cells

Innate immune cells in the tumor microenvironment have been proposed to control the transition from benign to malignant stages. In many cancers, increased infiltration of natural killer (NK) cells associates with good prognosis. Although the mechanisms that enable NK cells to restrain colorectal cancer (CRC) are unclear, the current study suggests the involvement of Smad4. We found suppressed Smad4 expression in circulating NK cells of untreated metastatic CRC patients. Moreover, NK cell-specific Smad4 deletion promoted colon adenomas in DSS-treated ApcMin/+ mice and adenocarcinomas in AOM/DSS-treated mice. Other studies have shown that Smad4 loss or weak expression in colonic epithelium associates with poor survival in CRC patients. Therefore, targeting Smad4 in both colonic epithelium and NK cells could provide an excellent opportunity to manage CRC. Toward this end, we showed that dietary intervention with black raspberries (BRBs) increased Smad4 expression in colonic epithelium in patients with FAP or CRC and in the two CRC mouse models. Also, benzoate metabolites of BRBs, such as hippurate, upregulated Smad4 and Gzmb expression that might enhance the cytotoxicity of primary human NK cells. Of note, increased levels of hippurate is a metabolomic marker of a healthy gut microbiota in humans, and hippurate also has antitumor effects. In conclusion, our study suggests a new mechanism for the action of benzoate metabolites derived from plant-based foods. This mechanism could be exploited clinically to upregulate Smad4 in colonic epithelium and NK cells, thereby delaying CRC progression.

Berry polyphenols metabolism and impact on human gut microbiota and health

Berries are rich in phenolic compounds such as phenolic acids, flavonols and anthocyanins. These molecules are often reported as being responsible for the health effects attributed to berries. However, their poor bioavailability, mostly influenced by their complex chemical structures, raises the question of their actual direct impact on health. The products of their metabolization, however, may be the most bioactive compounds due to their ability to enter the blood circulation and reach the organs. The main site of metabolization of the complex polyphenols to smaller phenolic compounds is the gut through the action of microorganisms, and reciprocally polyphenols and their metabolites can also modulate the microbial populations. In healthy subjects, these modulations generally lead to an increase in Bifidobacterium, Lactobacillus and Akkermansia, therefore suggesting a prebiotic-like effect of the berries or their compounds. Finally, berries have been demonstrated to alleviate symptoms of gut inflammation through the modulation of pro-inflammatory cytokines and have chemopreventive effects towards colon cancer through the regulation of apoptosis, cell proliferation and angiogenesis. This review recapitulates the knowledge available on the interactions between berries polyphenols, gut microbiota and gut health and identifies knowledge gaps for future research.

Chemopreventive Effect of Dietary Anthocyanins against Gastrointestinal Cancers: A Review of Recent Advances and Perspectives

Anthocyanins are a group of dietary polyphenols, abundant mainly in fruits and their products. Dietary interventions of anthocyanins are being studied extensively related to the prevention of gastrointestinal (GI) cancer, among many other chronic disorders. This review summarizes the hereditary and non-hereditary characteristics of GI cancers, chemistry, and bioavailability of anthocyanins, and the most recent findings of anthocyanin in GI cancer prevention through modulating cellular signaling pathways. GI cancer-preventive attributes of anthocyanins are primarily due to their antioxidative, anti-inflammatory, and anti-proliferative properties, and their ability to regulate gene expression and metabolic pathways, as well as induce the apoptosis of cancer cells.

Anti-colonic Inflammation by Black Raspberries through Regulating Toll-like Receptor-4 Signaling in Interlukin-10 Knockout Mice

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon, with a steadily rising prevalence in Western and newly industrialized countries. UC patients have a cancer incidence as high as 10% after 20 years of the disease. Although the importance of fruits and vegetables in defense against UC is beginning to be appreciated, the mechanisms remain largely unclear. In the current study, we reported that dietary black raspberries (BRBs) decreased colonic inflammation in the mucosa and submucosa of interleukin (IL)-10 knockout (KO) mice. We then used colon, spleen, and plasma from those mice to investigate whether BRBs exert their anti-inflammatory effects by correcting dysregulated toll-like receptor (TLR)-4 signaling to downregulate prostaglandin E2 (PGE2). Other studies reported that spleen is the reservoir of macrophages and depletion of macrophages in IL-10 KO mice prevents the development of colitis. Our results showed that BRBs decreased the percentages of macrophages in spleens of IL-10 KO mice. Moreover, mechanistically, the BRB diet corrected dysregulated TLR-4 signaling in cells from the colon and spleen, decreased PGE2 and prostaglandin I2, and increased 15-lipoxygenase and its product, 13-S-hydroxyoctadecadienoic acid, in plasma of IL-10 KO mice. Therefore, we have elucidated one of the anti-inflammatory mechanisms of BRBs, and have identified biomarkers that could be indicators of response in UC patients treated with them. Our findings with BRBs could well apply to many other commonly consumed fruits and vegetables.

Black raspberries suppress pancreatic cancer through modulation of NKp46+, CD8+, and CD11b+ immune cells

Pancreatic ductal adenocarcinoma (PDAC) is a fatal disease with a low survival rate (9%). Epidemiologic studies show that healthy dietary patterns enriched of fruits and vegetables lower the risk of PDAC. We previously showed that supplementing black raspberries (BRBs) to patients with colorectal cancer increased tumor-infiltrating NK cells and their cytotoxicity. We aimed to determine whether BRBs combat PDAC by modulating cancer immunity. NOD.SCID mice lacking T and B cells were injected with human Panc-1-Luc cells orthotopically, and immunocompetent Kras ^LSL.G12D/+ -Trp53 ^LSL.R172H/+ -Pdx-1-Cre mice were fed BRBs. Peripheral blood mononuclear cells (PBMCs) from PDAC patients were treated with butyrate, a microbial metabolite of BRBs. The absence of T and B cells did not dampen BRBs' anti-tumor effects in the NOD.SCID mice. In the Kras ^LSL.G12D/+ -Trp53 ^LSL.R172H/+ -Pdx-1-Cre mice, BRBs significantly prolonged survival (189 days versus 154 days). In both models, BRBs decreased tumor-infiltrating CD11b⁺ cells and the expression of IL-1β, sEH, and Ki67. BRBs also increased tumor-infiltrating NKp46⁺ cells and the expression of CD107a, a functional marker of cytolytic NK and CD8⁺ T cells. In Kras ^LSL.G12D/+ -Trp53 ^LSL.R172H/+ -Pdx-1-Cre mice, tumor infiltration of CD8⁺ T cells was increased by BRBs. Further using the PBMCs from PDAC patients, we show that butyrate decreased the population of myeloid-derived suppressor cells (MDSCs). Butyrate also reversed CD11b⁺ cell-mediated suppression on CD8⁺ T cells. Interestingly, there is a negative association between MDSC changes and patients' survival, suggesting that the more decrease in MDSC population induced by butyrate treatment, the longer the patient had survived. Our study suggests the immune-modulating potentials of BRBs in PDAC.

Molecular mechanisms linking environmental toxicants to cancer development: Significance for protective interventions with polyphenols

Human exposure to environmental toxicants with diverse mechanisms of action is a growing concern. In addition to well-recognized carcinogens, various chemicals in environmental and occupational settings have been suggested to impact health, increasing susceptibility to cancer by inducing genetic and epigenetic changes. Accordingly, in this review, we have discussed recent insights into the pathological mechanisms of these chemicals, namely their effects on cell redox and calcium homeostasis, mitochondria and inflammatory signaling, with a focus on the possible implications for multi-stage carcinogenesis and its reversal by polyphenols. Plant-derived polyphenols, such as epigallocatechin-gallate, resveratrol, curcumin and anthocyanins reduce the incidence of cancer and can be useful nutraceuticals for alleviating the detrimental outcomes of harmful pollutants. However, development of therapies based on polyphenol administration requires further studies to validate the biological efficacy, identifying effective doses, mode of action and new delivery forms. Innovative microphysiological testing models are presented and specific proposals for future trials are given. Merging the current knowledge of multifactorial actions of specific polyphenols and chief environmental toxicants, this work aims to potentiate the delivery of phytochemical-based protective treatments to individuals at high-risk due to environmental exposure.

Review of the health effects of berries and their phytochemicals on the digestive and immune systems

Berries are generally considered beneficial to health. This health-promoting potential has mainly been ascribed to berries' phytochemical and vitamin content, and little attention has been paid to the potential benefits of berries for the digestive tract, despite this being the first point of contact. In vivo studies that described the health effects of berries on individual parts of the digestive tract (ie, the mouth, esophagus, stomach, small and large intestine, microbiome, and immune system) were reviewed. Immune effects were included because a large part of the immune system is located in the intestine. Beneficial health effects were mainly observed for whole berry extracts, not individual berry components. These effects ranged from support of the immune system and beneficial microbiota to reduction in the number and size of premalignant and malignant lesions. These results demonstrate the potency of berries and suggest berries can serve as a strong adjuvant to established treatments or therapies for a variety of gastrointestinal and immune-related illnesses.

Chemopreventive Effects of Strawberry and Black Raspberry on Colorectal Cancer in Inflammatory Bowel Disease

Colorectal cancer (CRC) remains the third most common cause of cancer-related death in the United States and the fourth globally with a rising incidence. Inflammatory bowel disease (IBD) is a chronic immunologically mediated disease that imposes a significant associated health burden, including the increased risk for colonic dysplasia and CRC. Carcinogenesis has been attributed to chronic inflammation and associated with oxidative stress, genomic instability, and immune effectors as well as the cytokine dysregulation and activation of the nuclear factor kappa B (NFκB) signaling pathway. Current anti-inflammation therapies used for IBD treatment have shown limited effects on CRC chemoprevention, and their long-term toxicity has limited their clinical application. However, natural food-based prevention approaches may offer significant cancer prevention effects with very low toxicity profiles. In particular, in preclinical and clinical pilot studies, strawberry and black raspberry have been widely selected as food-based interventions because of their potent preventive activities. In this review, we summarize the roles of strawberry, black raspberry, and their polyphenol components on CRC chemoprevention in IBD.

Advances in phytochemical delivery systems for improved anticancer activity

Natural compounds have significant anticancer pharmacological activities, but often suffer from low bioavailability and selectivity that limit therapeutic use. The present work critically analyzes the latest advances on drug delivery systems designed to enhance pharmacokinetics, targeting, cellular uptake and efficacy of anticancer phytoconstituents. Various phytochemicals, including flavonoids, resveratrol, celastrol, curcumin, berberine and camptothecins, carried by liposomes, nanoparticles, nanoemulsions and films showed promising results. Strategies to avoid drug metabolism, overcome physiological barriers and achieve higher concentration at cancer sites through skin, buccal, nasal, vaginal, pulmonary and colon targeted delivery are presented. Current limitations, challenges and future research directions are also discussed.

Effects of Black Raspberries and Their Ellagic Acid and Anthocyanin Constituents on Taxane Chemotherapy of Castration-Resistant Prostate Cancer Cells

Cancer patients often use dietary supplements while on therapy, but little is known about interactions of supplements with cancer chemotherapy. Black raspberries (BRB) have anti-cancer effects, but have not been evaluated for interference with chemotherapy for castrate-resistant prostate cancer (CRPC). Here we studied whether BRB and some of their constituents interact with docetaxel and cabazitaxel on CRPC cells in culture and implanted into nude mice. Ellagic acid increased, but BRB extract inhibited, microtubule assembly. Ellagic acid decreased tubulin polymerization by cabazitaxel and bound to tubulin. Ellagic acid, its metabolite urolithin A, BRB extract, and the anthocyanin metabolite protocatechuic acid (PCA) did not alter cytotoxicity of taxanes. Ellagic acid inhibited drug efflux in CRPC cells, but BRB extract and PCA did not. None of these compounds altered CYP3A4 activity. Although dietary ellagic acid did not alter the tumor growth inhibition by docetaxel of xenografted 22Rv1 cells, ellagic acid has the potential to interfere with taxane chemotherapy by reducing tubulin polymerization while inhibiting P-glycoprotein drug efflux. These data are cause for concern of consuming ellagic acid during treatment for CRPC and indicate need for further research, but BRB consumption appears safe.

Chemoprevention of Colorectal Cancer by Dietary Compounds

Colorectal cancer is one of the leading causes of death, and the third most diagnosed type of cancer, worldwide. It is most common amongst men and women over 50 years old. Risk factors include smoking, alcohol, diet, physical inactivity, genetics, alterations in gut microbiota, and associated pathologies (diabetes, obesity, chronic inflammatory bowel diseases). This review will discuss, in detail, the chemopreventive properties of some dietary compounds (phenolic compounds, carotenoids, iridoids, nitrogen compounds, organosulfur compounds, phytosterols, essential oil compounds, polyunsaturated fatty acids and dietary fiber) against colorectal cancer. We present recent data, focusing on in vitro, laboratory animals and clinical trials with the previously mentioned compounds. The chemopreventive properties of the dietary compounds involve multiple molecular and biochemical mechanisms of action, such as inhibition of cell growth, inhibition of tumor initiation, inhibition of adhesion, migration and angiogenesis, apoptosis, interaction with gut microbiota, regulation of cellular signal transduction pathways and xenobiotic metabolizing enzymes, etc. Moreover, this review will also focus on the natural dietary compounds' bioavailability, their synergistic protective effect, as well as the association with conventional therapy. Dietary natural compounds play a major role in colorectal chemoprevention and continuous research in this field is needed.

Relevance of functional foods in the Mediterranean diet: the role of olive oil, berries and honey in the prevention of cancer and cardiovascular diseases

The traditional Mediterranean diet (MedDiet) is a well-known dietary pattern associated with longevity and improvement of life quality as it reduces the risk of the most common chronic pathologies, such as cancer and cardiovascular diseases (CVDs), that represent the principal cause of death worldwide. One of the most characteristic foods of MedDiet is olive oil, a very complex matrix, which constitutes the main source of fats and is used in the preparation of foods, both raw as an ingredient in recipes, and in cooking. Similarly, strawberries and raspberries are tasty and powerful foods which are commonly consumed in the Mediterranean area in fresh and processed forms and have attracted the scientific and consumer attention worldwide for their beneficial properties for human health. Besides olive oil and berries, honey has lately been introduced in the MedDiet thanks to its relevant nutritional, phytochemical and antioxidant profile. It is a sweet substance that has recently been classified as a functional food. The aim of this review is to present and discuss the recent evidence, obtained from in vitro, in vivo and epidemiological studies, on the potential roles exerted by these foods in the prevention and progression of different types of cancer and CVDs.

Effects of dietary interventions on DNA methylation in adult humans: systematic review and meta-analysis

DNA methylation is a key component of the epigenetic machinery that is responsible for regulating gene expression and, therefore, cell function. Patterns of DNA methylation change during development and ageing, differ between cell types, are altered in multiple diseases and can be modulated by dietary factors. However, evidence about the effects of dietary factors on DNA methylation patterns in humans is fragmentary. This study was initiated to collate evidence for causal links between dietary factors and changes in DNA methylation patterns. We carried out a systematic review of dietary intervention studies in adult humans using Medline, EMBASE and Scopus. Out of 22 149 screened titles, sixty intervention studies were included, of which 65% were randomised (n 39). Most studies (53%) reported data from blood analyses, whereas 27% studied DNA methylation in colorectal mucosal biopsies. Folic acid was the most common intervention agent (33%). There was great heterogeneity in the methods used for assessing DNA methylation and in the genomic loci investigated. Meta-analysis of the effect of folic acid on global DNA methylation revealed strong evidence that supplementation caused hypermethylation in colorectal mucosa (P=0·009). Meta-regression analysis showed that the dose of supplementary folic acid was the only identified factor (P<0·001) showing a positive relationship. In summary, there is limited evidence from intervention studies of effects of dietary factors, other than folic acid, on DNA methylation patterns in humans. In addition, the application of multiple different assays and investigations of different genomic loci makes it difficult to compare, or to combine, data across studies.

A phase I pilot study evaluating the beneficial effects of black raspberries in patients with Barrett's esophagus

Black raspberries inhibit a broad range of cancers in preclinical models which has led to clinical evaluations targeting premalignant lesions of the colon, oral cavity and esophagus. A phase I pilot study was conducted in twenty Barrett's esophagus (BE) patients to investigate the effect of lyophilized black raspberries (LBR) on urinary metabolites and markers of lipid peroxidation, DNA damage and tissue markers of cellular proliferation, detoxification, and inflammation. Surveys, biopsies, blood and urine samples were collected before and after 6 months of LBR treatment (32 or 45 g). LBR significantly reduced urinary excretion of 8-epi-prostaglandin F2α, a marker of lipid peroxidation linked to oxidative stress and free radical damage. Urinary levels of the ellagitannin metabolites, urolithin A-glucuronide, urolithin A-sulfate and dimethylellagic acid glucuronide were significantly increased following 12 and 26 weeks of LBR consumption and may prove useful as indicators of compliance in future clinical studies. Immunohistochemical staining of BE biopsies following LBR treatment showed significant increases in mean GST-pi levels, with 55.6% of subjects responding favorably. In summary, LBR significantly decreased urinary lipid peroxidation levels and significantly increased GST-pi, a marker of detoxification, in BE epithelium. Still, LBR may need to be formulated differently, administered at higher concentrations or multiple times a day to increase efficacy.

Impact of dietary gut microbial metabolites on the epigenome

Within the past decade, epigenetic mechanisms and their modulation by natural products have gained increasing interest. Dietary bioactive compounds from various sources, including green tea, soya, fruit and berries, cruciferous vegetables, whole grain foods, fish and others, have been shown to target enzymes involved in epigenetic gene regulation, including DNA methyltransferases, histone acetyltransferases, deacetylases and demethylases in vitro and in cell culture. Also, many dietary agents were shown to alter miRNA expression. In vivo studies in animal models and humans are still limited. Recent research has indicated that the gut microbiota and gut microbial metabolites might be important mediators of diet-epigenome interactions. Inter-individual differences in the gut microbiome might affect release, metabolism and bioavailability of dietary agents and explain variability in response to intervention in human studies. Only a few microbial metabolites, including folate, phenolic acids, S-(-)equol, urolithins, isothiocyanates, and short- and long-chain fatty acids have been tested with respect to their potential to influence epigenetic mechanisms. Considering that a complex mixture of intermediary and microbial metabolites is present in human circulation, a more systematic interdisciplinary investigation of nutri-epigenetic activities and their impact on human health is called for.This article is part of a discussion meeting issue 'Frontiers in epigenetic chemical biology'.

The role of nutrition in influencing mechanisms involved in environmentally mediated diseases

Human exposure to environmental contaminants such as persistent chlorinated organics, heavy metals, pesticides, phthalates, flame retardants, electronic waste and airborne pollutants around the world, and especially in Southeast Asian regions, are significant and require urgent attention. Given this widespread contamination and abundance of such toxins as persistent organic pollutants (POPs) in the ecosystem, it is unlikely that remediation alone will be sufficient to address the health impacts associated with this exposure. Furthermore, we must assume that the impact on health of some of these contaminants results in populations with extraordinary vulnerabilities to disease risks. Further exacerbating risk; infectious diseases, poverty and malnutrition are common in the Southeast Asian regions of the world. Thus, exploring preventive measures of environmental exposure and disease risk through new paradigms of environmental toxicology, optimal and/or healthful nutrition and health is essential. For example, folic acid supplementation can lower blood arsenic levels, and plant-derived bioactive nutrients can lower cardiovascular and cancer risks linked to pollutant exposure. Data also indicate that diets enriched with bioactive food components such as polyphenols and omega-3 polyunsaturated fatty acids can prevent or decrease toxicant-induced inflammation. Thus, consuming healthy diets that exhibit high levels of antioxidant and anti-inflammatory properties, is a meaningful way to reduce the vulnerability to non-communicable diseases linked to environmental toxic insults. This nutritional paradigm in environmental toxicology requires further study in order to improve our understanding of the relationship between nutrition or other lifestyle modifications and toxicant-induced diseases. Understanding mechanistic relationships between nutritional modulation of environmental toxicants and susceptibility to disease development are important for both cumulative risk assessment and the design and implementation of future public health programs and behavioral interventions.

The urinary phenolic acid profile varies between younger and older adults after a polyphenol-rich meal despite limited differences in in vitro colonic catabolism

PURPOSE

To investigate whether age influences colonic polyphenol metabolism.

METHODS

Healthy participants, younger (n = 8; 23-43 years) and older (n = 13; 51-76 years), followed a 3-day low-polyphenol diet (LPD) and a 3-day high-polyphenol diet (HPD). Urinary phenolic acids (PA), short chain fatty acids (SCFA), pH and gas were monitored, alongside selected colonic bacteria. Human faecal in vitro fermentations of rutin with or without raftiline were used to evaluate the gut microbiota capacity in a subset of both groups.

RESULTS

Total urinary PA were higher in the older group after HPD compared to the younger group (1.5-fold; p = 0.04), with no difference between groups in terms of a change between diets (Δ high-low diet). While 17 PA were detected in all younger participants after HPD, a narrower range (n = 8 to 16 PA) was detected in most (n = 9/13) older participants, with lower level of benzoic acid (19-fold; p = 0.03), vanillic acid (4.5-fold; p = 0.04) but higher hippuric acid (2.7-fold; p = 0.03). Faecal SCFA concentration did not change after HPD within group, with similar differential excretion (Δ high-low diet) between groups. There were no differences between groups for faecal pH, total, faecal bacteria including Flavonifractor plautii, bifidobacteria, and bacteroides. In human in vitro faecal fermentations, seven PAs were detected in both groups after 24 h of rutin fermentation, with no quantitative and modest qualitative differences between groups. Total SCFA in faecal fermentation did not differ between groups, except for butyric acid (twofold higher in the older group; p = 0.009) when rutin was fermented with raftiline over 24 h.

CONCLUSIONS

Urinary phenolic acids were less diverse in older participants despite limited difference in functional capacity of in vitro faecal fermentations.

Could Aspirin and Diets High in Fiber Act Synergistically to Reduce the Risk of Colon Cancer in Humans?

Early inhibition of inflammation suppresses the carcinogenic process. Aspirin is the most commonly used non-steroid anti-inflammatory drugs (NSAIDs), and it irreversibly inhibits cyclooxygenase-1 and -2 (COX1, COX2). Multiple randomized clinical trials have demonstrated that aspirin offers substantial protection from colon cancer mortality. The lower aspirin doses causing only minimal gastrointestinal disturbance, ideal for long-term use, can achieve only partial and transitory inhibition of COX2. Aspirin’s principal metabolite, salicylic acid, is also found in fruits and vegetables that inhibit COX2. Other phytochemicals such as curcumin, resveratrol, and anthocyanins also inhibit COX2. Such dietary components are good candidates for combination with aspirin because they have little or no toxicity. However, obstacles to using phytochemicals for chemoprevention, including bioavailability and translational potential, must be resolved. The bell/U-shaped dose–response curves seen with vitamin D and resveratrol might apply to other phytochemicals, shedding doubt on ‘more is better’. Solutions include: (1) using special delivery systems (e.g., nanoparticles) to retain phytochemicals; (2) developing robust pharmacodynamic biomarkers to determine efficacy in humans; and (3) selecting pharmacokinetic doses relevant to humans when performing preclinical experiments. The combination of aspirin and phytochemicals is an attractive low-cost and low-toxicity approach to colon cancer prevention that warrants testing, particularly in high-risk individuals.

A nutrigenetic approach for investigating the chemopreventive effects of black raspberries during the development of preneoplastic esophagi in rats

BACKGROUND

Large epidemiological studies have shown that diets high in fruits reduce the risk of esophageal squamous cell carcinoma (ESCC).

OBJECTIVE

The current study investigated the effects of black raspberries (BRBs) on gene expression during the development of preneoplastic esophagi in rats.

METHODS

Using a post-initiation protocol, F344 rats were injected with N-nitrosomethylbenzylamine (NMBA) and then fed either a control diet or 5% BRBs. At weeks 9, 15, and 35, we euthanized subgroups of the rats and collected preneoplastic esophagi to isolate RNA samples for DNA microarray.

RESULTS

Along the development of NMBA-induced preneoplastic esophagi, NMBA injections led to differential expression of 1181 genes comparing to control rats, and dietary BRBs modulated 428 genes in esophagi from NMBA-treated rats. There are 137 common genes between 1181 and 428 gene sets, and BRBs significantly reversed the expression of 133 genes. These genes are associated with multiple gene oncology functions. BRBs induced an 8.8-fold gene enrichment on the pathway of inflammatory response and regulated 10 genes involved in this pathway. Among them, BRBs significantly reversed the expression of pro-inflammatory cytokines, such as CCL2, S100A8, and IL19.

CONCLUSIONS

BRBs exhibit strong anti-inflammatory effects against NMBA-induced rat esophageal tumorigenesis.

Gut bacteria are required for the benefits of black raspberries in Apc Min/+ mice

BACKGROUND

The gut microbiota plays a pivotal role in the development of inflammatory bowel disease and colorectal cancer.

OBJECTIVE

To determine whether the gut microbiota is required for the chemoprotective effects of black raspberries (BRBs) in Apc ^Min/+ mice.

METHODS

Apc ^Min/+ mice were given (a) a control diet for 8 weeks, or (b) the control diet for 4 weeks and then a 5% BRB diet for additional 4 weeks, or (c) the control diet and antibiotics for 4 weeks followed by the 5% BRB diet and antibiotics for the next 4 weeks. At the end of the study, all the mice were euthanized, and colonic and intestinal polyps were counted. mRNA expression levels of TLR4, NF-κB1, and COX2 were determined in colon and small intestine of these Apc ^Min/+ mice by quantitative real-time PCR.

RESULTS

5% BRBs significantly suppressed intestinal and colonic polyp development in the Apc ^Min/+ mice, whereas antibiotics significantly abolished BRBs' chemoprotective effects. BRBs decreased mRNA levels of TLR4, NF-κB1, and COX2 in colon, whereas significantly enhanced mRNA levels of TLR4 and NF-κB1 were observed in small intestine of BRB-treated Apc ^Min/+ mice fed antibiotics.

CONCLUSIONS

The gut microbiota is required for BRBs' chemoprotection against polyp development in Apc ^Min/+ mice.

Inhibition of the development of N-nitrosomethylbenzylamine-induced esophageal tumors in rats by strawberries and aspirin, alone and in combination

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of two subtypes of esophageal cancer, with high incidence and mortality rates in developing countries.

OBJECTIVE

The current study investigated the potential chemoprotective effects of strawberries and aspirin against the development of rat esophageal papillomas, the precursors to ESCC.

METHODS

Using a prevention model, we administered study diets to rats before, during, and after N-nitrosomethylbenzylamine (NMBA) treatment. The effects of the four diets were evaluated: the control diet, 5% strawberry powder in the control diet, 0.01% aspirin in the drinking water, and the combination of strawberries and aspirin. At week 25, we euthanized all the rats and collected their esophagi to quantify tumor incidence, multiplicity, and burden, as well as for molecular analysis.

RESULTS

Both strawberries and aspirin significantly decreased esophageal tumor multiplicity, with the combination causing the most robust suppression. Aspirin alone and the combination decreased the total tumor burden in the esophagus. None of the diets had a significant effect on tumor incidence or the expression of COX-1 and COX-2. Strawberries and aspirin, alone and in combination, significantly suppressed squamous epithelial cell proliferation (PCNA).

CONCLUSIONS

Strawberries, aspirin, and their combination exhibit chemoprotective effects against NMBA-induced esophageal tumors in rats.

Wnt Signalling-Targeted Therapy in the CMS2 Tumour Subtype: A New Paradigm in CRC Treatment?

Colorectal cancers (CRC) belonging to the consensus molecular subtype 2 (CMS2) have the highest incidence rate, affect mainly the distal colon and rectum, and are characterized by marked Wnt/β-catenin/Transcription Factor 7-Like 2 (TCF7L2) pathway activation and also by activation of epidermal growth factor receptor (EGFR) signalling. Despite having the highest overall survival, CMS2 tumours are often diagnosed at stage III when an adjuvant chemotherapy-based regimen is recommended. Nevertheless, colorectal cancer stem cells (CSCs) and circulating tumour cells may still evade the current therapeutic options and metastasize, stressing the need to develop more tailored therapeutic strategies. For example, activation of EGFR signalling is being used as a target for tailored therapy, however, therapy resistance is frequently observed. Therefore, targeting the Wnt signalling axis represents an additional therapeutic strategy, considering that CMS2 tumours are "Wnt-addicted". Several efforts have been made to identify Wnt antagonists, either of synthetic or natural origin. However, an inverse gradient of Wnt/β-catenin/TCF7L2 signalling activity during CRC progression has been suggested, with early stage and metastatic tumours displaying high and low Wnt signalling activities, respectively, which lead us to revisit the "just-right" signalling model. This may pinpoint the use of Wnt signalling agonists instead of antagonists for treatment of metastatic stages, in a context-dependent fashion. Moreover, the poor immunogenicity of these tumours challenges the use of recently emerged immunotherapies. This chapter makes a journey about CMS2 tumour characterization, their conventional treatment, and how modulation of Wnt signalling or immune response may be applied to CRC therapy. It describes the newest findings in this field and indicates where more research is required.

The Impact of Dietary Polyphenols on COX-2 Expression in Colorectal Cancer

Polyphenols are natural compounds with high structural diversity whose common occurrence in plants renders them intrinsic dietary components. They are known to be secondary metabolites characterized by a wide spectrum of biological activities, and a growing body of evidence indicates they have anti-inflammatory potential. It is well known that inflammation plays a key role in many chronic diseases such as circulatory diseases, pulmonary diseases, autoimmune diseases, diabetes, cancer, and neurodegenerative diseases. Polyphenols influence the inflammatory process by controlling and inhibiting pro-inflammatory cytokines such as IL-1β, IL-6, IL-8, and TNF-α, and cyclooxygenase-2 (COX-2) enzyme involved in the metabolism of arachidonic acid. Furthermore, polyphenols exhibit anti-inflammatory activity on many levels via NF-κB inhibition, and MAPK, iNOS, and growth factors regulation. This paper reviews the current state of knowledge concerning the potential of various dietary polyphenols to inhibit the effects of COX-2 in colon cancer, by examining the available evidence regarding the efficacy and safety of these compounds obtained from in vitro and animal studies.

Black Raspberries Enhance Natural Killer Cell Infiltration into the Colon and Suppress the Progression of Colorectal Cancer

Natural killer (NK) cells are an essential component of innate immunity against cancer development. Many studies have been conducted to evaluate immune-modulating effects using dietary compounds. Our laboratory has been investigating the chemopreventive potential of black raspberries (BRBs) and previously demonstrated their beneficial modulation of genetic and epigenetic biomarkers in patients with colorectal cancer (CRC). The current study investigated their potential on modulating NK cells. To avoid the excessive inflammation caused by the dextran sulfate sodium (DSS) treatment that leads to colitis, we treated the mice with overnight DSS so that it would slightly irritate the colon but still promote colon carcinogenesis with 100% incidence in both the Apc^Min/+ mice and azoxymethane (AOM)-treated mice. A significant decrease of tissue-infiltrating NK cells along the progression of microadenoma-to-adenoma and adenoma-to-adenocarcinoma was observed in the Apc^Min/+ /DSS and AOM/DSS mice, respectively. Depletion of NK cells significantly promoted the development of CRC, suggesting a critical role of NK cells in combating CRC progression. BRBs significantly suppressed the CRC progression and increased the number of tissue-infiltrating NK cells in both mouse models. Moreover, we further determined BRBs' effects on NK cells in the human biopsy specimens collected from our previously completed clinical trial, in which CRC patients consumed BRBs for an average of 4 weeks during a presurgical window. We observed an increased number and an enhanced cytotoxicity of NK cells by BRB intervention. The current study provides evidence that BRBs have the potential to enhance the tumor immunesurveillance of NK cells that can be beneficial in the setting of CRC prevention and treatment.

Black Raspberries and Their Anthocyanin and Fiber Fractions Alter the Composition and Diversity of Gut Microbiota in F-344 Rats

Natural compounds can alter the diversity and composition of the gut microbiome, potentially benefiting our health. We previously demonstrated chemopreventive effects of black raspberries (BRBs) in colorectal cancer, which is associated with gut dysbiosis. To investigate the effects of whole BRBs and their fractions on gut microbiota, we fed F-344 rats a control diet, 5% BRBs, the BRB anthocyanin fraction, or the BRB residue fraction for 6 weeks. Feces were collected at baseline and at weeks 3 and 6, and bacterial sequence counts were analyzed. We observed distinct patterns of microbiota from different diet groups. Beta diversity analysis suggested that all diet groups exerted time-dependent changes in the bacterial diversity. Hierarchical clustering analysis revealed that post-diet fecal microbiota was segregated from baseline fecal microbiota within each diet. It is interesting to note that fractions of BRBs induced different changes in gut bacteria compared to whole BRBs. The abundance of specific microbial species known to have anti-inflammatory effects, such as Akkermansia and Desulfovibrio, was increased by whole BRBs and their residue. Further, butyrate-producing bacteria, e.g., Anaerostipes, were increased by whole BRBs. Our results suggest that whole BRBs and their fractions alter the gut microbiota in ways that could significantly influence human health.

Application of a low polyphenol or low ellagitannin dietary intervention and its impact on ellagitannin metabolism in men

SCOPE

Plant polyphenols are widespread in the American diet, yet estimated intake is uncertain. We examine the application of the Polyphenol Explorer® (PED) database to quantify polyphenol and ellagitannin (ET) intake of men with prostate cancer and tested the implementation of diets restricted in polyphenols or ETs.

METHODS AND RESULTS

Twenty-four men enrolled in a 4-week trial were randomized to usual, low-polyphenol or low-ET diet. Estimated polyphenol and ET intakes were calculated from 3-day diet records utilizing the PED. Urine and plasma metabolites were quantified by UPLC-MS. Adherence to the restricted diets was 95% for the low polyphenol and 98% for low-ET diet. In the usual diet, estimated dietary polyphenol intake was 1568 ± 939 mg/day, with coffee/tea beverages (1112 ± 1028 mg/day) being the largest contributors and estimated dietary ET intake was 12 ± 13 mg/day. The low-polyphenol and low-ET groups resulted in a reduction of total polyphenols by 45% and 85%, respectively, and omission of dietary ETs. UPLC analysis of urinary host and microbial metabolites reflect ET intake.

CONCLUSION

PED is a useful database for assessing exposure to polyphenols. Diets restricted in total polyphenol or ET intake are feasible and UPLC assessment of ET metabolites is reflective of dietary intake.

Systemic Metabolite Changes in Wild-type C57BL/6 Mice Fed Black Raspberries

INTRODUCTION

Freeze-dried black raspberries (BRBs) elicit chemopreventive effects against colorectal cancer in humans and in rodents. The objective of this study was to investigate potential BRB-caused metabolite changes using wild-type (WT) C57BL/6 mice.

METHODS AND RESULTS

WT mice were fed either control diet or control diet supplemented with 5% BRBs for 8 wk. A nontargeted metabolomic analysis was conducted on colonic mucosa, liver, and fecal specimens collected from both diet groups. BRBs significantly changed the levels of 41 colonic mucosa metabolites, 40 liver metabolites, and 34 fecal metabolites compared to control diet-fed mice. BRBs reduced 34 lipid metabolites in colonic mucosa and increased levels of amino acids in liver. One metabolite, 3-[3-(sulfooxy) phenyl] propanoic acid, might be a useful biomarker of BRB consumption. In addition, BRB powder was found to contain 30-fold higher levels of linolenate compared to control diets. Consistently, multiple omega-3 polyunsaturated fatty acids (ω-3 PUFAs), including stearidonate, docosapentaenoate (ω-3 DPA), eicosapentaenoate (EPA), and docosahexaenoate (DHA), were significantly elevated in livers of BRB-fed mice.

CONCLUSION

The data from the current study suggest that BRBs produce systemic metabolite changes in multiple tissue matrices, supporting our hypothesis that BRBs may serve as both a chemopreventive agent and a beneficial dietary supplement.