Chemoprevention of esophageal cancer with black raspberries, their component anthocyanins, and a major anthocyanin metabolite, protocatechuic acid

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.

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.

Re-Examination of the Esophageal Squamous Cell Carcinoma Model in Rats Induced by N-Nitrososarcosine Ethyl Ester Precursors

Studies of the molecular mechanisms of esophageal cancer development have to be carried out on sufficient amount of tumor material, obtained under conditions of controlled exposure to carcinogenic factors. Esophageal cancer models on laboratory animals serve an indispensable source of this material. One of these models is esophageal cancer induction in rats by N-nitroso compound precursors. Despite adequate reproduction of human esophageal cancer, this model in fact has not been used since the 1990ies. Re-examination of esophageal cancer model, induced by N-nitrososarcosine ethyl ester precursors, is carried out and its efficiency in induction of squamous cell carcinoma is confirmed.

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.

Effects of Black Raspberry Extract and Berry Compounds on Repair of DNA Damage and Mutagenesis Induced by Chemical and Physical Agents in Human Oral Leukoplakia and Rat Oral Fibroblasts

Black raspberries (BRB) have been shown to inhibit carcinogenesis in a number of systems, with most studies focusing on progression. Previously we reported that an anthocyanin-enriched black raspberry extract (BE) enhanced repair of dibenzo-[a,l]-pyrene dihydrodiol (DBP-diol)-induced DNA adducts and inhibited DBP-diol and DBP-diolepoxide (DBPDE)-induced mutagenesis in a lacI rat oral fibroblast cell line, suggesting a role for BRB in the inhibition of initiation of carcinogenesis. Here we extend this work to protection by BE against DNA adduct formation induced by dibenzo-[a,l]-pyrene (DBP) in a human oral leukoplakia cell line (MSK) and to a second carcinogen, UV light. Treatment of MSK cells with DBP and DBPDE led to a dose-dependent increase in DBP-DNA adducts. Treatment of MSK cells with BE after addition of DBP reduced levels of adducts relative to cells treated with DBP alone, and treatment of rat oral fibroblasts with BE after addition of DBPDE inhibited mutagenesis. These observations showed that BE affected repair of DNA adducts and not metabolism of DBP. As a proof of principle we also tested aglycones of two anthocyanins commonly found in berries, delphinidin chloride and pelargonidin chloride. Delphinidin chloride reduced DBP-DNA adduct levels in MSK cells, while PGA did not. These results suggested that certain anthocyanins can enhance repair of bulky DNA adducts. As DBP and its metabolites induced formation of bulky DNA adducts, we investigated the effects of BE on genotoxic effects of a second carcinogen that induces bulky DNA damage, UV light. UV irradiation produced a dose-dependent increase in cyclobutanepyrimidine dimer levels in MSK cells, and post-UV treatment with BE resulted in lower cyclobutanepyrimidine dimer levels. Post-UV treatment of the rat lacI cells with BE reduced UV-induced mutagenesis. Taken together, the results demonstrate that BE extract reduces bulky DNA damage and mutagenesis and support a role for BRB in the inhibition of initiation of carcinogenesis.

Inhibition of Pro-inflammatory and Anti-apoptotic Biomarkers during Experimental Oral Cancer Chemoprevention by Dietary Black Raspberries

Oral cancer continues to be a significant public health problem worldwide. Recently conducted clinical trials demonstrate the ability of black raspberries (BRBs) to modulate biomarkers of molecular efficacy that supports a chemopreventive strategy against oral cancer. However, it is essential that a preclinical animal model of black raspberry (BRB) chemoprevention which recapitulates human oral carcinogenesis be developed, so that we can validate biomarkers and evaluate potential mechanisms of action. We therefore established the ability of BRBs to inhibit oral lesion formation in a carcinogen-induced rat oral cancer model and examined potential mechanisms. F344 rats were administered 4-nitroquinoline 1-oxide (4NQO) (20 µg/ml) in drinking water for 14 weeks followed by regular drinking water for 6 weeks. At week 14, rats were fed a diet containing either 5 or 10% BRB, or 0.4% ellagic acid (EA), a BRB phytochemical. Dietary administration of 5 and 10% BRB reduced oral lesion incidence and multiplicity by 39.3 and 28.6%, respectively. Histopathological analyses demonstrate the ability of BRBs and, to a lesser extent EA, to inhibit the progression of oral cancer. Oral lesion inhibition by BRBs was associated with a reduction in the mRNA expression of pro-inflammatory biomarkers Cxcl1, Mif, and Nfe2l2 as well as the anti-apoptotic and cell cycle associated markers Birc5, Aurka, Ccna1, and Ccna2. Cellular proliferation (Ki-67 staining) in tongue lesions was inhibited by BRBs and EA. Our study demonstrates that, in the rat 4NQO oral cancer model, dietary administration of BRBs inhibits oral carcinogenesis via inhibition of pro-inflammatory and anti-apoptotic pathways.

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.

Effects of anthocyanins on the prevention and treatment of cancer

Anthocyanins are a class of water-soluble flavonoids, which show a range of pharmacological effects, such as prevention of cardiovascular disease, obesity control and antitumour activity. Their potential antitumour effects are reported to be based on a wide variety of biological activities including antioxidant; anti-inflammation; anti-mutagenesis; induction of differentiation; inhibiting proliferation by modulating signal transduction pathways, inducing cell cycle arrest and stimulating apoptosis or autophagy of cancer cells; anti-invasion; anti-metastasis; reversing drug resistance of cancer cells and increasing their sensitivity to chemotherapy. In this review, the latest progress on the anticancer activities of anthocyanins and the underlying molecular mechanisms is summarized using data from basic research in vitro and in vivo, from clinical trials and taking into account theory and practice.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

Structure Based docking studies towards exploring potential anti-androgen activity of selected phytochemicals against Prostate Cancer

Prostate cancer (PCa) is the second most common malignancy amongst men worldwide. Under PCa maintenance therapy drugs acting as antagonists/partial agonists of hormone receptors against the prostate tissue are used in clinical practices. Prominent drugs being Cyproterone acetate, Flutamide, Bicalutamide, they not only cause acute and long-term toxicity, but also develops drug resistance among patients. Our focus has been on phytochemicals which do not exhibit any cytotoxicity and have significant androgen receptor (AR) inhibition activity. As Protein- Ligand interactions play a key role in structure based drug design, so by using molecular docking, we screened 803 phytochemicals and investigated their binding affinity against AR. The three dimensional (3D) structure of AR was retrieved from Protein Data Bank, and docked with 3D Pubchem structures of 803 phytochemicals using Argus Lab. Molecular docking and drug likeness studies were made using ADMET properties while Lipinski's rule of five was performed for the phytochemicals to evaluate their anti-prostate cancer activity. The results showed that Isobavachin exhibited best binding affinity of -13.73 kcal/mol with AR followed by Glabranin, Anthocyanin and Eriosemation. Our studies therefore reveal that these four phytochemicals could be promising candidates for further evaluation for PCa prevention or management.

Health benefits of anthocyanins and molecular mechanisms: Update from recent decade

Anthocyanins are one of the most widespread families of natural pigments in the plant kingdom. Their health beneficial effects have been documented in many in vivo and in vitro studies. This review summarizes the most recent literature regarding the health benefits of anthocyanins and their molecular mechanisms. It appears that several signaling pathways, including mitogen-activated protein kinase, nuclear factor κB, AMP-activated protein kinase, and Wnt/β-catenin, as well as some crucial cellular processes, such as cell cycle, apoptosis, autophagy, and biochemical metabolism, are involved in these beneficial effects and may provide potential therapeutic targets and strategies for the improvement of a wide range of diseases in future. In addition, specific anthocyanin metabolites contributing to the observed in vivo biological activities, structure-activity relationships as well as additive and synergistic efficacy of anthocyanins are also discussed.

Human intervention study to investigate the intestinal accessibility and bioavailability of anthocyanins from bilberries

We investigated the importance of the large intestine on the bioavailability of anthocyanins from bilberries in humans with/without a colon. Low bioavailability of anthocyanins in plasma and urine was observed in the frame of this study. Anthocyanins reached the circulation mainly as glucuronides. Analysis of ileal effluents (at end of small intestine) demonstrated that 30% of ingested anthocyanins were stable during 8h passage through the upper intestine. Only 20% degradants were formed and mostly intact anthocyanins were absorbed from the small intestine. Higher amounts of degradants than anthocyanins reached the circulation after bilberry extract consumption in both groups of subjects. Comparison of the bioavailability of anthocyanins in healthy subjects versus ileostomists revealed substantially higher amounts of anthocyanins and degradants in the plasma/urine of subjects with an intact gut. The results suggested that the colon is a significant site for absorption of bioactive components such as anthocyanins and their degradation products.

Potential Benefits of Edible Berries in the Management of Aerodigestive and Gastrointestinal Tract Cancers: Preclinical and Clinical Evidence

Epidemiological reports as well as experimental studies have demonstrated the significant health benefits provided by regular berry consumption. Berries possess both prophylactic and therapeutic potential against several chronic illnesses, such as cardiovascular, neurodegenerative, and neoplastic diseases. Berries owe their health benefits to phytoconstituents, such as polyphenolic anthocyanins, ellagic acid, and a diverse array of phytochemicals bestowed with potent antioxidant and anti-inflammatory effects as well as the ability to engage a multitude of signaling pathways. This review highlights the principal chemical constituents present in berries and their primary molecular targets. The article presents and critically analyzes the chemopreventive and therapeutic potential of berry extracts, fractions, and bioactive components on various cancers of the gastrointestinal tract (GIT), including esophageal, stomach, intestinal, and colorectal cancers as well as cancers of the upper aerodigestive tract, such as oral cancer. The current status of clinical studies evaluating berry products in several aforementioned cancers is presented. Various emerging issues including dose-ranging and dosage forms, the role of synergy and the usage of combination therapy as well as other relevant areas essential for the development of berry phytoconstituents as mainstream chemopreventive and therapeutic agents against aerodigestive and GIT cancers are critically discussed.

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.

Metabolic engineering of anthocyanins in dark tobacco varieties

In this study, we investigate the metabolic engineering of anthocyanins in two dark tobacco crops (Narrow Leaf Madole and KY171) and evaluate the effects on physiological features of plant photosynthesis. Arabidopsis PAP1 (production of anthocyanin pigment 1) gene (AtPAP1) encodes a R2R3-type MYB transcript factor that is a master component of regulatory complexes controlling anthocyanin biosynthesis. AtPAP1 was introduced to Narrow Leaf Madole and KY171 plants. Multiple transgenic plants developed red/purple pigmentation in different tissues. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis showed that the expression levels of six pathway genes were increased two- to eight-fold in AtPAP1 transgenic plants compared with vector control plants. Dihydroflavonol reductase and anthocyanidin synthase genes that were not expressed in wild-type plants were activated. Spectrophotometric measurement showed that the amount of anthocyanins in AtPAP1 transgenic plants were 400-800 µg g-1 fresh weight (FW). High-performance liquid chromatography (HPLC) analysis showed that one main anthocyanin molecule accounted for approximately 98% of the total anthocyanins. Tandem MS/MS analysis using HPLC coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry identified the main anthocyanin as cyanidin 3-O-rutinoside, an important medicinal anthocyanin. Analysis of photosynthesis rate, chlorophylls and carotenoids contents showed no differences between red/purple transgenic and control plants, indicating that this metabolic engineering did not alter photosynthetic physiological traits. This study shows that AtPAP1 is of significance for metabolic engineering of anthocyanins in crop plants for value-added traits.

Antibiotics and specialized metabolites from the human microbiota

Human microbiota associated with each body site produce specialized molecules to kill human pathogens. Advanced bioinformatics tools will help to discover unique microbiome chemistry.

Black raspberries demethylate Sfrp4, a WNT pathway antagonist, in rat esophageal squamous cell papilloma

Aberrant methylation of DNA is a common event in the development of cancers, including squamous cell carcinoma (SCC) of the human esophagus. In the present study, we determined: (a) whether aberrant DNA methylation also occurs in the development of N-nitrosomethylbenzylamine (NMBA)-induced tumorigenesis in the rat esophagus, a model of human esophageal SCC; and (b) if so, whether dietary black raspberries (BRBs) are capable of preventing this aberrant DNA methylation. A diet containing 5% BRBs inhibited the development of NMBA-induced tumors in the rat esophagus. This inhibition was associated with reduced mRNA levels of the DNA methyltransferases, Dnmt1 and Dnmt3b, in both dysplastic lesions and in papillomas of the esophagus. In addition, promoter methylation of Sfrp4, a WNT pathway antagonist, was significantly reduced by the berry diet, and this was associated with decreased nuclear localization of β-CATENIN and reduced expression of c-MYC protein in NMBA-treated esophagi. Decreased promoter methylation of Sfrp4 correlated with decreased expression of Dmnt3b and, ultimately, with increased Sfrp4 mRNA expression. This suggests that epigenetic alterations in NMBA-induced rat esophageal tumorigenesis recapitulate epigenetic events in human esophageal SCC, and that BRBs could be useful in preventing the aberrant DNA methylation involved in the development of human esophageal SCC. © 2015 Wiley Periodicals, Inc.

Targeting arachidonic acid pathway by natural products for cancer prevention and therapy

Arachidonic acid (AA) pathway, a metabolic process, plays a key role in carcinogenesis. Hence, AA pathway metabolic enzymes phospholipase A₂s (PLA₂s), cyclooxygenases (COXs) and lipoxygenases (LOXs) and their metabolic products, such as prostaglandins and leukotrienes, have been considered novel preventive and therapeutic targets in cancer. Bioactive natural products are a good source for development of novel cancer preventive and therapeutic drugs, which have been widely used in clinical practice due to their safety profiles. AA pathway inhibitory natural products have been developed as chemopreventive and therapeutic agents against several cancers. Curcumin, resveratrol, apigenin, anthocyans, berberine, ellagic acid, eugenol, fisetin, ursolic acid, [6]-gingerol, guggulsteone, lycopene and genistein are well known cancer chemopreventive agents which act by targeting multiple pathways, including COX-2. Nordihydroguaiaretic acid and baicalein can be chemopreventive molecules against various cancers by inhibiting LOXs. Several PLA₂s inhibitory natural products have been identified with chemopreventive and therapeutic potentials against various cancers. In this review, we critically discuss the possible utility of natural products as preventive and therapeutic agents against various oncologic diseases, including prostate, pancreatic, lung, skin, gastric, oral, blood, head and neck, colorectal, liver, cervical and breast cancers, by targeting AA pathway. Further, the current status of clinical studies evaluating AA pathway inhibitory natural products in cancer is reviewed. In addition, various emerging issues, including bioavailability, toxicity and explorability of combination therapy, for the development of AA pathway inhibitory natural products as chemopreventive and therapeutic agents against human malignancy are also discussed.

Food-based natural products for cancer management: Is the whole greater than the sum of the parts?

The rise in cancer incidence and mortality in developing countries together with the human and financial cost of current cancer therapy mandates a closer look at alternative ways to overcome this burgeoning global healthcare problem. Epidemiological evidence for the association between cancer and diet and the long latency of most cancer progression have led to active exploration of whole and isolated natural chemicals from different naturally occurring substances in various preclinical and clinical settings. In general the lack of systemic toxicities of most 'whole' and 'isolated' natural compounds, their potential to reduce toxic doses and potential to delay the development of drug-resistance makes them promising candidates for cancer management. This review article examines the suggested molecular mechanisms affected by these substances focusing to a large extent on prostate cancer and deliberates on the disparate results obtained from cell culture, preclinical and clinical studies in an effort to highlight the use of whole extracts and isolated constituents for intervention. As such these studies underscore the importance of factors such as treatment duration, bioavailability, route of administration, selection criteria, standardized formulation and clinical end points in clinical trial design with both entities. Overall lack of parallel comparison studies between the whole natural products and their isolated compounds limits decisive conclusions regarding the superior utility of one over the other. We suggest the critical need for rigorous comparative research to identify which one of the two or both entities from nature would be best qualified to take on the mantle of cancer management.

Efficacy comparison of lyophilised black raspberries and combination of celecoxib and PBIT in prevention of carcinogen-induced oesophageal cancer in rats

The objective of this study was to compare the efficacy and mechanism of lyophilized black raspberries (BRB) versus the combination of celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, and S,S'-1,4-phenylene-bis(1,2-ethanediyl)bis-isothiourea (PBIT), a selective inducible nitric oxide synthase (iNOS) inhibitor in inhibition of carcinogen-induced esophageal squamous cell carcinoma in rats. Our data indicated that tumor multiplicity and histologic grade of esophageal precancerous lesions were reduced in animals fed BRB compared to those fed celecoxib + PBIT. The mechanistic studies showed that BRB and its major anthocyanin suppressed cell proliferation and oncogenic signaling. Our findings demonstrated that dietary BRB is superior to the combination of two pharmaceutical drugs in esophageal cancer prevention. These observations suggest the potential value of translational studies using BRB food products for esophageal cancer prevention in humans, particularly those with high-risk premalignant lesions.

Urolithin A suppresses the proliferation of endometrial cancer cells by mediating estrogen receptor-α-dependent gene expression

SCOPE

Obese and overweight women are at high risk of developing endometrial cancer; indeed, many of endometrial cancer patients are obese. The increased number and size of adipocytes due to obesity elevate levels of circulating estrogens that stimulate cell proliferation in the endometrium. However, black raspberries are a promising approach to preventing endometrial cancer.

METHODS AND RESULTS

We examined 17 black raspberry constituents and metabolites (10 μM or 10 μg/mL, 48 h) for their ability to prevent endometrial cancer cells from proliferating. Urolithin A (UA) was most able to suppress proliferation in a time- and dose-dependent manner (p < 0.05). It arrested the G2/M phase of the cell cycle by upregulating cyclin-B1, cyclin-E2, p21, phospho-cdc2, and CDC25B. UA also acted as an estrogen agonist by modulating estrogen receptor-α (ERα) dependent gene expression in ER-positive endometrial cancer cells. UA enhanced the expression of ERβ, PGR, pS2, GREB1 while inhibiting the expression of ERα and GRIP1. Coincubating UA-treated cells with the estrogen antagonist ICI182,780 abolished UA's estrogenic effects. Knocking down ERα suppressed PGR, pS2, and GREB gene expression but increased GRIP1 expression. Thus, UA's actions appear to be mediated through ERα.

CONCLUSION

This study suggests that UA modulates ERα-dependent gene expression, thereby inhibiting endometrial cancer proliferation.

Effect of Rubus Occidentalis Extract on Metabolic Parameters in Subjects with Prediabetes: A Proof-of-concept, Randomized, Double-blind, Placebo-controlled Clinical Trial

Rubus occidentalis (RO) has beneficial effects on glucose and lipid profiles in vitro. The aim of the study was to investigate RO extract effect on metabolic parameters in prediabetic patients, adopting a 12-week, randomized, double-blind, placebo-controlled trial. Forty-four patients (age 59.0 ± 8.2 years, 70.5% females, HbA1c 5.8 ± 0.4%) were divided into placebo (n = 13), low-dose RO extract (LRE; n = 14), or high-dose RO extract (HRE; n = 17) groups. Either 900 or 1800 mg per day of RO extract was administered orally. Area under the curve for glucose obtained 2 h after a 75-g oral glucose tolerance test was significantly decreased in the HRE group, compared with the placebo group (-28.1 ± 42.4 vs. +13.4 ± 52.6 mg/dL, p < 0.05). Homoeostasis model assessment-B was increased (+17.11 ± 10.69, +5.24 ± 4.10, and +0.86 ± 6.01 in HRE, LRE, and placebo, respectively, p < 0.05). Serum levels of monocyte chemoattractant protein-1 and oxidized low-density lipoprotein were significantly decreased by treatment in a dose-dependent manner (monocyte chemoattractant protein-1: -35.0 ± 21.2, +8.4 ± 18.1, and +24.2 ± 14.5; oxidized low-density lipoprotein: -19.7 ± 8.5, -13.1 ± 7.2, and -2.2 ± 11.0 in the HRE, LRE, and placebo, respectively, p < 0.05). The results support the beneficial effects of RO extract on the control of glycemia and vascular inflammation in prediabetic patients. (ClinicalTrials.gov: NCT01964703). Copyright © 2016 John Wiley & Sons, Ltd.

Flavonoids, Flavonoid Subclasses, and Esophageal Cancer Risk: A Meta-Analysis of Epidemiologic Studies

Flavonoids have been suggested to play a chemopreventive role in carcinogenesis. However, the epidemiologic studies assessing dietary intake of flavonoids and esophageal cancer risk have yielded inconsistent results. This study was designed to examine the association between flavonoids, each flavonoid subclass, and the risk of esophageal cancer with a meta-analysis approach. We searched for all relevant studies with a prospective cohort or case-control study design published from January 1990 to April 2016, using PUBMED, EMBASE, and Web of Science. Pooled odds ratios (ORs) were calculated using fixed or random-effect models. In total, seven articles including 2629 cases and 481,193 non-cases were selected for the meta-analysis. Comparing the highest-intake patients with the lowest-intake patients for total flavonoids and for each flavonoid subclass, we found that anthocyanidins (OR = 0.60, 95% CI: 0.49-0.74), flavanones (OR = 0.65, 95% CI: 0.49-0.86), and flavones (OR = 0.78, 95% CI 0.64-0.95) were inversely associated with the risk of esophageal cancer. However, total flavonoids showed marginal association with esophageal cancer risk (OR = 0.78, 95% CI: 0.59-1.04). In conclusion, our study suggested that dietary intake of total flavonoids, anthocyanidins, flavanones, and flavones might reduce the risk of esophageal cancer.

Effects of Black Raspberry Extract and Protocatechuic Acid on Carcinogen-DNA Adducts and Mutagenesis, and Oxidative Stress in Rat and Human Oral Cells

Effects of black raspberry (BRB) extract and protocatechuic acid (PCA) on DNA adduct formation and mutagenesis induced by metabolites of dibenzo[a,l]pyrene (DBP) were investigated in rat oral fibroblasts. The DBP metabolites, (±)-anti-11,12-dihydroxy-11,12,-dihydrodibenzo[a,l]pyrene (DBP-diol) and 11,12-dihydroxy-13,14-epoxy-11,12,13,14-tetrahydrodibenzo[a,l]pyrene (DBPDE) induced dose-dependent DNA adducts and mutations. DBPDE was considerably more potent, whereas the parent compound had no significant effect. Treatment with BRB extract (BRBE) and PCA resulted in reduced DBP-derived DNA adduct levels and reduced mutagenesis induced by DBP-diol, but only BRBE was similarly effective against (DBPDE). BRBE did not directly inactivate DBPDE, but rather induced a cellular response-enhanced DNA repair. When BRBE was added to cells 1 day after the DBP-diol, the BRBE greatly enhanced removal of DBP-derived DNA adducts. As oxidative stress can contribute to several stages of carcinogenesis, BRBE and PCA were investigated for their abilities to reduce oxidative stress in a human leukoplakia cell line by monitoring the redox indicator, 2',7'-dichlorodihydrofluorescein diacetate (H2DCF) in cellular and acellular systems. BRBE effectively inhibited the oxidation, but PCA was only minimally effective against H2DCF. These results taken together provide evidence that BRBE and PCA can inhibit initiation of carcinogenesis by polycyclic aromatic hydrocarbons; and in addition, BRBE reduces oxidative stress. Cancer Prev Res; 9(8); 704-12. ©2016 AACR.

The Chemistry of Gut Microbial Metabolism of Polyphenols

Gut microbiota contribute to the metabolism of dietary polyphenols and affect the bioavailability of both the parent polyphenols and their metabolites. Although there is a large number of reports of specific polyphenol metabolites, relatively little is known regarding the chemistry and enzymology of the metabolic pathways utilized by specific microbial species and taxa, which is the focus of this review. Major classes of dietary polyphenols include monomeric and oligomeric catechins (proanthocyanidins), flavonols, flavanones, ellagitannins, and isoflavones. Gut microbial metabolism of representatives of these polyphenol classes can be classified as A- and C-ring cleavage (retro Claisen reactions), C-ring cleavage mediated by dioxygenases, dehydroxylations (decarboxylation or reduction reactions followed by release of H₂O molecules), and hydrogenations of alkene moieties in polyphenols, such as resveratrol, curcumin, and isoflavones (mediated by NADPH-dependent reductases). The qualitative and quantitative metabolic output of the gut microbiota depends to a large extent on the metabolic capacity of individual taxa, which emphasizes the need for assessment of functional analysis in conjunction with determinations of gut microbiota compositions.

FBXO4 loss facilitates carcinogen induced papilloma development in mice

Cyclin D1 is frequently overexpressed in esophageal squamous cell carcinoma (ESCC) and is considered a key driver of this disease. Mutations in FBXO4, F-box specificity factor that directs SCF-mediated ubiquitylation of cyclin D1, occur in ESCC with concurrent overexpression of cyclin D1 suggesting a potential tumor suppressor role for FBXO4. To evaluate the contribution of FBXO4-dependent regulation cyclin D1 in esophageal squamous cell homeostasis, we exposed FBXO4 knockout mice to N-nitrosomethylbenzylamine (NMBA), an esophageal carcinogen. Our results revealed that loss of FBXO4 function facilitates NMBA induced papillomas in FBXO4 het (+/-) and null (-/-) mice both by numbers and sizes 11 months after single dose NMBA treatment at 2mg/kg by gavage when compared to that in wt (+/+) mice (P < 0.01). No significant difference was noted between heterozygous or nullizygous mice consistent with previous work. To assess cyclin D1/CDK4 dependence, mice were treated with the CDK4/6 specific inhibitor, PD0332991, for 4 weeks. PD0332991 treatment (150mg/kg daily), reduced tumor size and tumor number. Collectively, our data support a role for FBXO4 as a suppressor of esophageal tumorigenesis.

Human microbial metabolites as a source of new drugs

Crosstalk between the microbiome and the human host is mediated by specific ligand-receptor interactions involving microbially generated metabolites that can be either agonists or antagonists of human proteins. The evolved co-compatibility of gut microbiota with human systems points to a potentially rich area for discovering new drug-like molecules that are both highly specific modulators of human pathways and derisked for adverse effects. In this review, we discuss the rapidly growing research into the role of microbial metabolites in human health and suggest potential strategies for developing these molecules into therapeutic agents.

Identification and Quantitation of Anthocyanins in Purple-Fleshed Sweet Potatoes Cultivated in China by UPLC-PDA and UPLC-QTOF-MS/MS

The identification and quantitation of the anthocyanins in 12 purple-fleshed sweet potato (PFSP) cultivars ('Jihei 1', 'Xuzi 3', 'Xuzi 6', 'Zhezi 4', 'Ningzi 1', 'Ningzi 2', 'Ningzi 3', 'Ning 2-2', 'Ning 6-8', 'Guangzi 1', 'Ziluolan', and 'Qinzi 1') in China were carried out using a combination of ultraperformance liquid chromatography-photodiode array (UPLC-PDA), quadrupole-time-of-flight mass spectrometry (QTOF-MS), and tandem mass spectrometry (MS/MS) analyses. Thirteen acylated anthocyanins were tentatively characterized, including two new PFSP anthocyanins, cyanidin 3-caffeoyl-vanilloyl sophoroside-5-glucoside and peonidin 3-caffeoyl-vanilloyl sophoroside-5-glucoside. The quantitative analyses of these anthocyanins were conducted using cyanidin 3-O-glucoside as a standard. The total anthocyanin content of the PFSPs depended on the cultivar. The five PFSP cultivars with the highest content of anthocyanins were 'Jihei 1', 'Xuzi 3', 'Zhezi 4', 'Ziluolan', and 'Qinzi 1'. This is the first report of the 'Ningzi 2', 'Ningzi 3', and 'Ning 2-2' PFSP cultivars containing only diacylated anthocyanins and of the 'Xuzi 6' cultivar containing single anthocyanidin-based anthocyanins.

Dendrimers with the protocatechuic acid building block for anticancer drug delivery

Protocatechuic acid (3,4-dihydroxybenzoic acid; PCA) is a well-known antioxidant compound and a potential antitumor drug that is commonly found in fruits and vegetables.

Black raspberries in cancer clinical trials: Past, present and future

BACKGROUND

Black raspberries (BRB) inhibit a broad range of cancers in preclinical models, including in vivo models of oral, esophageal, colon, breast and skin cancer. Promising preclinical results have led to clinical evaluations in cancer patients or patients at increased risk for cancer development.

OBJECTIVE

To summarize clinical investigations targeting cancer or precancerous lesions with BRB and discuss future directions.

METHODS

A thorough literature search was conducted through December 1, 2015 to identify all published studies evaluating BRB in cancer focused clinical trials.

RESULTS

Research investigating BRB in clinical settings report positive effects on preneoplastic lesions or cancers of the oral cavity, esophagus and colon. BRB treatment resulted in: histologic regression of oral intraepithelial neoplasia associated with improved histologic grade and significantly reduced loss of heterozygosity at tumor suppressor gene loci, modulated genes linked to RNA processing and growth factor recycling; in the colon, BRB inhibited FAP-associated polyp progression, demethylated tumor suppressor genes and improved plasma cytokine profiles; in Barrett's patients, BRB consumption increased tissue levels of GST-pi and decreased 8-isoprostane, a marker of lipid peroxidation/oxidative stress.

CONCLUSIONS

The precise dose, duration and optimum mode of BRB delivery for cancer inhibition remains to be fully elucidated. Common themes across studies support that BRB are anti-proliferative, anti- inflammatory, reduce oxidative stress and restore tumor suppressive activity. Future directions are included in the conclusions section.

A multi-targeted approach to suppress tumor-promoting inflammation

Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-κB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes.

Dietary Consumption of Black Raspberries or Their Anthocyanin Constituents Alters Innate Immune Cell Trafficking in Esophageal Cancer

Freeze-dried black raspberries (BRB), their component anthocyanins (AC), and a metabolite of BRB ACs, protocatechuic acid (PCA), inhibit the development of esophageal cancer in rats induced by the carcinogen, N-nitrosomethylbenzylamine (NMBA). All three components reduce inflammation in the esophagus and in plasma. The present study determined the relation of changes in inflammatory markers to infiltration of innate immune cells into NMBA-treated esophagus. Rats were injected with NMBA (0.35 mg/kg) for 5 weeks while on control diet. Following NMBA treatment, rats were fed diets containing 6.1% BRB powder, an AC-rich fraction of BRBs (3.8 μmol/g), or 500 ppm PCA. At weeks 15, 25, and 35, inflammatory biomarker expression in the plasma and esophagus was quantified, and infiltration of immune cells in the esophagus was examined. At all three time points, BRB, AC, and PCA similarly affected cytokine production in the esophagus and plasma of NMBA-treated rats, relative to the NMBA-only control. These included decreased expression of the proinflammatory cytokine IL1β and increased expression of the anti-inflammatory cytokine IL10. Moreover, all three diets also increased the expression of IL12, a cytokine that activates both cytolytic natural killer and CD8(+) T cells. In addition, the three diets also decreased infiltration of both macrophages and neutrophils into the esophagus. Overall, our results suggest that another mechanism by which BRBs, ACs, and PCA inhibit NMBA-induced esophageal tumorigenesis is by altering cytokine expression and innate immune cell trafficking into tumor tissues.

Metabolomic Analysis Reveals Cyanidins in Black Raspberry as Candidates for Suppression of Lipopolysaccharide-Induced Inflammation in Murine Macrophages

The extracts produced by multisolvent extraction and subfractionation with preparative liquid chromatography of black raspberry (Rubus coreanus Miquel) cultivated in Gochang, South Korea, were tested for their anti-inflammatory effects. The metabolomic profiling and analysis by orthogonal partial least-squares discriminant analysis (OLPS-DA) suggested that cyanidin, cyanidin-3-glucoside (C3G), and cyanidin-3-rutinoside (C3R) were key components for the anti-inflammatory responses in the most active fraction BF3-1, where they were present at 0.44, 1.26, and 0.56 μg/mg of BF3-1, respectively. Both BF3-1 and mixture of these cyanidins at the same ratio reduced lipopolysaccharide (LPS)-induced protein level of iNOS expression and suppressed mRNA and protein expressions of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β through inhibiting the phosphorylation of mitogen-activated protein kinases (MAPKs) and STAT3 in murine macrophage RAW264.7 cells. Overall, the results suggested that co-administration of cyanidin, C3G, and C3R is more effective than that of cyanidin alone and that the coexistence of these anthocyanin components in black raspberry plays a vital role in regulating LPS-induced inflammation even at submicromolar concentrations, making it possible to explain the health beneficial activity of its extracts.

Pharmacological properties of protocatechuic Acid and its potential roles as complementary medicine

This paper reviews the reported pharmacological properties of protocatechuic acid (PCA, 3,4-dihydroxy benzoic acid), a type of phenolic acid found in many food plants such as olives and white grapes. PCA is a major metabolite of anthocyanin. The pharmacological actions of PCA have been shown to include strong in vitro and in vivo antioxidant activity. In in vivo experiments using rats and mice, PCA has been shown to exert anti-inflammatory as well as antihyperglycemic and antiapoptotic activities. Furthermore, PCA has been shown to inhibit chemical carcinogenesis and exert proapoptotic and antiproliferative effects in different cancerous tissues. Moreover, in vitro studies have shown PCA to have antimicrobial activities and also to exert synergistic interaction with some antibiotics against resistant pathogens. This review aims to comprehensively summarize the pharmacological properties of PCA reported to date with an emphasis on its biological properties and mechanisms of action which could be therapeutically useful in a clinical setting.

Flavan-3-ols, anthocyanins, and inflammation

The process of inflammation constitutes a reactive response of the organism to tissue damage and is an important factor making part of a number of degenerative pathologies as insulin resistance, dyslipidemia, and hypertension, all of them comprised in the metabolic syndrome. There is an increasing interest in plant products rich in flavan-3-ols and anthocyanins because of their potential beneficial effects observed in epidemiological studies against inflammatory-related diseases. Their anti-inflammatory effects are exerted by modulation of cell redox status and inhibition of signaling pathways as NF-κB activation. The effects depend on their concentrations in target tissues and hence the bioavailability pathways followed by each particular compound. In this sense, in vitro studies performed with parental compounds at doses exceeding to those found in vivo may be drawing erroneous conclusions about their real efficacy. Contradictory results have been observed in human intervention trials, which may be ascribed to the type of population studied, length of study, source of flavan-3-ol/anthocyanin, and dose provided. Human studies are required to confirm the positive effects found in vitro and in animal models. Future research should be focused on the understanding of dose/flavonoid intake-response relationship with pharmacokinetic studies, evaluating proper biomarkers of intake. Long-term dietary interventions are necessary to observe effects on markers of late activation as well as the possible preventive effects of these compounds on long-term inflammation-related diseases.