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

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.

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.

Dysregulated Free Fatty Acid Receptor 2 Exacerbates Colonic Adenoma Formation in Apc Min/+ Mice: Relation to Metabolism and Gut Microbiota Composition

Free fatty acid receptor 2 (FFAR2) has been reported as a tumor suppressor in colon cancer development. The current study investigated the effects of FFAR2 signaling on energy metabolism and gut microbiota profiling in a colorectal cancer mouse model (Apc Min/+ ). Ffar2 deficiency promoted colonic polyp development and enhanced fatty acid oxidation and bile acid metabolism. Gut microbiome sequencing analysis showed distinct clustering among wild-type, Apc Min/+ , and Apc Min/+ -Ffar2 -/- mice. The relative abundance of Flavobacteriaceae and Verrucomicrobiaceae was significantly increased in the Apc Min/+ -Ffar2 -/- mice compared to the Apc Min/+ mice. In addition, knocking-down FFAR2 in the human colon cancer cell lines (SW480 and HT29) resulted in increased expression of several key enzymes in fatty acid oxidation, such as carnitine palmitoyltransferase 2, acyl-CoA dehydrogenase, long-chain acyl-CoA dehydrogenase, C-2 to C-3 short chain, and hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase, alpha subunit. Collectively, these results demonstrated that Ffar2 deficiency significantly altered profiles of fatty acid metabolites and gut microbiome, which might promote colorectal cancer development.

Synthesis and Anti-Hepatocarcinoma Effect of Amino Acid Derivatives of Pyxinol and Ocotillol

Aiming at seeking an effective anti-hepatocarcinoma drug with low toxicity, a total of 24 amino acid derivatives (20 new along with 4 known derivatives) of two active ocotillol-type sapogenins (pyxinol and ocotillol) were synthesized. Both in vitro and in vivo anti-hepatocarcinoma effects of derivatives were evaluated. At first, the HepG2 human cancer cell was employed to evaluate the anti-cancer activity. Most of the derivatives showed obvious enhanced activity compared with pyxinol or ocotillol. Among them, compound 2e displayed the most excellent activity with an IC₅₀ value of 11.26 ± 0.43 µM. Next, H22 hepatoma-bearing mice were used to further evaluate the anti-liver cancer activity of compound 2e. It was revealed that the growth of H22 transplanted tumor was significantly inhibited when treated with compound 2e or compound 2e combined with cyclophosphamide (CTX) (p < 0.05, p < 0.01), and the inhibition rates of tumor growth were 35.32% and 55.30%, respectively. More importantly, compound 2e caused limited damage to liver and kidney in contrast with CTX causing significant toxicity. Finally, the latent mechanism of compound 2e was explored by serum and liver metabolomics based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) technology. A total of 21 potential metabolites involved in 8 pathways were identified. These results suggest that compound 2e is a promising agent for anti-hepato-carcinoma, and that it also could be used in combination with CTX to increase efficiency and to reduce toxicity.

Transplanting fecal material from wild-type mice fed black raspberries alters the immune system of recipient mice

By constantly stimulating intestinal immunity, gut microbes play important regulatory roles, and their possible involvement in human physical and mental disorders beyond intestinal diseases suggests the importance of maintaining homeostasis in the gut microbiota. Both transplantation of fecal microbiota and dietary interventions have been shown to restore microbial homeostasis in recipients. In the current study with wild-type mice, we combined these two approaches to determine if transplanting fecal material from mice fed black raspberries (BRB, 5%) altered recipients' immune system. The donors received a control or 5% BRB diet, and fecal transplantation was performed every other day 15 times into recipients fed control diet. Afterward, we used flow cytometry to analyze populations of CD3+ T, CD4+ T, CD8+ T cells, and NK cells among bone marrow cells, splenocytes, and peripheral blood mononuclear cells (PBMCs) collected from the recipients. We found that BRB-fecal material that contained both fecal microbiota and their metabolites increased NK cell populations among bone marrow cells, splenocytes, and PBMCs, and raised levels of CD8+ T cells in splenocytes. Our findings suggest that fecal transplantation can modulate the immune system and might therefore be valuable for managing a range of physical and mental disorders.

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.

Malvidin 3-Glucoside Modulated Gut Microbial Dysbiosis and Global Metabolome Disrupted in a Murine Colitis Model Induced by Dextran Sulfate Sodium

SCOPE

This study aims to elucidate the mechanisms of the anthocyanin malvidin 3-glucoside (MV) in alleviating gut dysbiosis using a murine colitis model induced by dextran sulfate sodium (DSS).

METHODS AND RESULTS

The effect of MV on the structure and function of the colon microbiome and microbial metabolism is evaluated using 16S rRNA gene sequencing, global metabolomics, and a network algorithm based on the random-matrix theory. MV ingestion improved histopathological scores and increased IL10 expression in the colon mucosa of colitis mice. While DSS has a profound effect on the gut microbiome and significantly decreases both microbial richness and evenness, MV further reduces evenness but promotes microbial interactions and restores the Firmicutes/Bacteroidetes ratio repressed by DSS. Moreover, MV reduces the abundance of pathogenic bacteria, such as Ruminococcus gnavus, in colitis mice and has a strong modulatory effect on microbial co-occurrence patterns and gut metabolites. In addition, MV reverses several key inflammatory mediators, including sphingolipid metabolites, from elevated levels in DSS colitis mice. As a bioactive ingredient, MV exerts its effect on the gut microbiome in a mechanism that differs from the whole blueberry.

CONCLUSION

MV ingestion ameliorates intestinal inflammation by modulating colon epithelium integrity, gut microbiome, and key inflammatory mediators.

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.

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'.

Colon Cancer: What We Eat

A higher incidence of colorectal cancer (CRC) is observed in Oceania and Europe, whereas Africa and Asia have a lower incidence. CRC is largely preventable by adapting a healthy lifestyle, such as healthy diet, adequate physical activity, and avoiding obesity. This review summarizes the latest work available, mainly epidemiologic studies, to examine the relationship between diet and CRC. Higher intake of red/processed meat could increase the CRC risk, whereas fibers, especially from whole grains and cereals, as well as fruit and vegetables may decrease the CRC risk. Heterogeneity and inconsistency among studies or individuals, however, need to be taken into consideration.

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.

An immunological perspective for preventing cancer with berries

Berries and their phytochemicals have well documented chemopreventive roles, but understanding their ability to regulate cancer immunology is only beginning to be explored. The literature, including human studies, suggests that berry components can modulate our immune system to delay cancer development. Moreover, their wide spectrum of phytochemicals suggests that they might influence the functions of multiple immune cells and different aspects of cancer immunity. Cancer immune-therapies are showing promise for some types of cancer because they boost T cells' ability to recognize tumor cells - an essential prelude to destruction. Recognition occurs after dendritic cells present antigen, such as tumor antigen, to T cells, generating an adaptive response. Therefore, the potential of berries to aid cancer immune-therapies by, for example, regulating dendritic cells, warrants further investigation in animal and human studies. More information is also needed about berries' effects on the entire spectrum of immunity so that a comprehensive view can inform efforts to use berries to enhance immune responses during cancer prevention and treatment. This review summarizes the effects of berries as anti-tumor agents from the immunological perspective in tumor-bearing animals and humans.

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.

Berries and other natural products in the pancreatic cancer chemoprevention in human clinical trials

Pancreatic ductal adenocarcinoma (PDAC) was the 12^th and 11^th most common cancer in men and women worldwide in 2012, with the highest incidence in North America and Europe and the lowest in Africa and Asia. Due to the lack of efficient early diagnosis and rapid disease progression, PDAC patients have a 5-year survival rate of just 5%. Epidemiological studies suggest that smoking, obesity, type II diabetes, and pancreatitis are common risk factors for PDAC development. By contrast, high intake of fresh fruit, vegetables, and nuts rich in phytochemicals could reduce PDAC risk. This review summarizes the human clinical studies that have used berries or other natural products for chemoprevention of PDAC. Developing chemopreventive agents against PDAC would be tremendously valuable for the high-risk population and patients with premalignant lesions. Although some clinical trials of these agents have been completed, most are in early phases, and the results are not promising, which may be due to administration of the natural products at advanced stages of PDAC. Thus, further mechanistic studies using genetic animal models that recapitulate the tumor microenvironment and immunology of human PDAC would be informative for selecting an effective window for intervention with berries or other natural compounds.