Walnut polyphenol extracts inhibit Helicobacter pylori-induced STAT3Tyr705 phosphorylation through activation of PPAR-γ and SOCS1 induction

Research on drug treatment and the novel signaling pathway of chronic atrophic gastritis

BACKGROUND

Chronic atrophic gastritis (CAG) is a global digestive system disease and one of the important causes of gastric cancer. The incidence of CAG has been increasing yearly worldwide.

PURPOSE

This article reviews the latest research on the common causes and future therapeutic targets of CAG as well as the pharmacological effects of corresponding clinical drugs. We provide a detailed theoretical basis for further research on possible methods for the treatment of CAG and reversal of the CAG process.

RESULTS

CAG often develops from chronic gastritis, and its main pathological manifestation is atrophy of the gastric mucosa, which can develop into gastric cancer. The drug treatment of CAG can be divided into agents that regulate gastric acid secretion, eradicate Helicobacter. pylori (H. pylori), protect gastric mucous membrane, or inhibit inflammatory factors according to their mechanism of action. Although there are limited specific drugs for the treatment of CAG, progress is being made in defining the pathogenesis and therapeutic targets of the disease. Growing evidence shows that NF-κB, PI3K/AKT, Wnt/ β-catenin, MAPK, Toll-like receptors (TLRs), Hedgehog, and VEGF signaling pathways play an important role in the development of CAG.

Antioxidant and Anti-Inflammatory Properties of Walnut Constituents: Focus on Personalized Cancer Prevention and the Microbiome

Walnuts have been lauded as a 'superfood', containing a remarkable array of natural constituents that may have additive and/or synergistic properties that contribute to reduced cancer risk. Walnuts are a rich source of polyunsaturated fatty acids (PUFAs: alpha-linolenic acid, ALA), tocopherols, antioxidant polyphenols (including ellagitannins), and prebiotics, including fiber (2 g/oz). There is a growing body of evidence that walnuts may contribute in a positive way to the gut microbiome, having a prebiotic potential that promotes the growth of beneficial bacteria. Studies supporting this microbiome-modifying potential include both preclinical cancer models as well as several promising human clinical trials. Mediated both directly and indirectly via its actions on the microbiome, many of the beneficial properties of walnuts are related to a range of anti-inflammatory properties, including powerful effects on the immune system. Among the most potent constituents of walnuts are the ellagitannins, primarily pedunculagin. After ingestion, the ellagitannins are hydrolyzed at low pH to release ellagic acid (EA), a non-flavonoid polyphenolic that is subsequently metabolized by the microbiota to the bioactive urolithins (hydroxydibenzo[b,d]pyran-6-ones). Several urolithins, including urolithin A, reportedly have potent anti-inflammatory properties. These properties of walnuts provide the rationale for including this tree nut as part of a healthy diet for reducing overall disease risk, including colorectal cancer. This review considers the latest information regarding the potential anti-cancer and antioxidant properties of walnuts and how they may be incorporated into the diet to provide additional health benefits.

Peroxisome proliferator-activated receptors regulate the progression and treatment of gastrointestinal cancers

Peroxisome proliferator-activated receptors (PPARs) are essential nuclear hormone receptors regulating metabolic processes, and they participate in the initiation and progression processes of tumors. Gastrointestinal (GI) cancer is a prevalent malignancy worldwide that originates from the tissues of the gastrointestinal tract and is characterized by severe symptoms and poor prognosis. Numerous published studies have investigated the critical role of PPARs in esophageal, gastric, and colorectal cancers. Here, we summarize and review the current literature to understand the role of PPARs in the pathogenesis of GI cancers and to provide a systematic reference for the subsequent investigation and development of efficient therapies targeting PPARs and their pathways.

Investigating the Tocopherol Contents of Walnut Seed Oils Produced in Different European Countries Analyzed by HPLC-UV: A Comparative Study on the Basis of Geographical Origin

A rapid HPLC-UV method was developed for the determination of tocopherols in walnut seed oils. The method was validated and the LODs ranged between 0.15 and 0.30 mg/kg, while the LOQs were calculated over the range of 0.50 to 1.00 mg/kg. The accuracy values ranged between 90.8 and 97.1% for the within-day assay (n = 6) and between 90.4 and 95.8% for the between-day assay (n = 3 × 3), respectively. The precision of the method was evaluated and the RSD% values were lower than 6.1 and 8.2, respectively. Overall, 40 samples of walnuts available on the Greek market, originating from four different European countries (Greece, Ukraine, France, and Bulgaria), were processed into oils and analyzed. One-way ANOVA was implemented in order to investigate potential statistically significant disparities between the concentrations of tocopherols in the walnut oils on the basis of the geographical origin, and Tukey's post hoc test was also performed to examine exactly which varieties differed. The statistical analysis of the results demonstrated that the Ukrainian walnut seed oils exhibited significantly higher total concentrations compared to the rest of the samples.

JAK2/STAT3 in role of arsenic-induced cell proliferation: a systematic review and meta-analysis

OBJECTIVES

Malignant cell proliferation is one of the important mechanisms of arsenic poisoning. A large number of studies have shown that STAT3 plays an important role in cell malignant proliferation, but there are still many contradictions in the effect of arsenic on JAK2/STAT3. This study aims to explore the role of JAK2/STAT3 in arsenic-induced cell proliferation.

METHODS

By taking normal cells as the research object and using Standard Mean Difference (SMD) as the effect size, meta-analysis was used to explore the effect of arsenic on JAK2/STAT3. Then, the dose-effect Meta was used to further clarify the dose-effect relationship of arsenic on JAK2/STAT3.

RESULTS

Through meta-analysis, this study found that arsenic could promote the phosphorylation of STAT3 (SMD=4.21, 95%CI [1.05, 7.37]), and increase IL-6 and p-JAK2, Vimentin, VEGF expression levels, thereby inducing malignant cell proliferation. In addition, this study also found that arsenic exposure dose (<5 μmol m^-3), time(<24 h) and cell type were important sources of heterogeneity in the process of exploring the effects of arsenic on p-STAT3, IL-6 and p-JAK2. Dose-effect relationship meta-analysis results showed that arsenic exposure significantly increased the expression level of IL-6. When the arsenic exposure concentration was less than 7 μmol m^-3, the expression level of p-JAK2 upregulated significantly as the arsenic exposure concentration gradually increasing. Moreover, the expression level of p-STAT3 elevated significantly with the gradual increase of the arsenic concentration under 5 μmol m^-3 of arsenic exposure, but the expression level of p-STAT3 gradually decreases when the concentration is greater than 5 μmol m^-3.

CONCLUSIONS

Exposure to low dose of arsenic could promote the expression of JAK2/STAT3 and induce the malignant proliferation of cells through upregulating IL-6, and there was dose-effect relationship among them.

Polyphenol Mechanisms against Gastric Cancer and Their Interactions with Gut Microbiota: A Review

The lack of new drugs and resistance to existing drugs are serious problems in gastric cancer(GC) treatment. The research found polyphenols possess anti-Helicobacter pylori(Hp) and antitumor activities and may be used in the research and development of drugs for cancer prevention and treatment. However, polyphenols are affected by their chemical structures and physical properties, which leads to relatively low bioavailability and bioactivity in vivo. The intestinal flora can improve the absorption, utilization, and biological activity of polyphenols, whereas polyphenol compounds can increase the richness of the intestinal flora, reduce the activity of carcinogenic bacteria, stabilize the proportion of core flora, and maintain homeostasis of the intestinal microenvironment. Our review summarizes the gastrointestinal flora-mediated mechanisms of polyphenol against GC.

Pharmacological Properties of Polyphenols: Bioavailability, Mechanisms of Action, and Biological Effects in In Vitro Studies, Animal Models, and Humans

Drugs are bioactive compounds originally discovered from chemical structures present in both the plant and animal kingdoms. These have the ability to interact with molecules found in our body, blocking them, activating them, or increasing or decreasing their levels. Their actions have allowed us to cure diseases and improve our state of health, which has led us to increase the longevity of our species. Among the molecules with pharmacological activity produced by plants are the polyphenols. These, due to their molecular structure, as drugs, also have the ability to interact with molecules in our body, presenting various pharmacological properties. In addition, these compounds are found in multiple foods in our diet. In this review, we focused on discussing the bioavailability of these compounds when we ingested them through diet and the specific mechanisms of action of polyphenols, focusing on studies carried out in vitro, in animals and in humans over the last five years. Knowing which foods have these pharmacological activities could allow us to prevent and aid as concomitant treatment against various pathologies.

Exploration of walnut components and their association with health effects

Traditionally, walnuts have occupied an imperative position in the functional food market with consistently recognized nutritious and functional properties. In the past years, the lipid profile of walnuts has brought much scientific attention via linking a cascade of biological attributes and health-promoting effects. Over time, researchers have focused on diversified composition (polyphenols and vitamins) of different parts of walnut (flower, pellicle, and kernel) and emphasized their physiological significance. Consequently, a plethora of reports has emerged on the potential role of walnut consumption against a series of diseases including cancer, gut dysbiosis, cardiovascular, and neurodegenerative diseases. Therefore, we accumulated the updated data on composition and classification, extraction methods, and utilization of different parts of walnuts as well as associated beneficial effects under in vivo and clinical studies. Altogether, this review summarized the ameliorative effects of a walnut-enriched diet in chronic diseases which can be designated to the synergistic or individual effects of walnut components mainly through anti-oxidative and anti-inflammatory role.

Dietary intake of walnut prevented Helicobacter pylori-associated gastric cancer through rejuvenation of chronic atrophic gastritis

The fact that Fat-1 transgenic mice producing n-3 polyunsaturated fatty acids via overexpressed 3-desaturase significantly mitigated Helicobacter pylori (H. pylori)-associated gastric tumorigenesis through rejuvenation of chronic atrophic gastritis (CAG) led us to study whether dietary intake of walnut plentiful of n-3 PUFAs can be nutritional intervention to prevent H. pylori-associated gastric cancer. In our model that H. pylori-initiated, high salt diet-promoted gastric carcinogenesis, pellet diet containing 100 mg/kg and 200 mg/kg walnut was administered up to 36 weeks. As results, control mice (24 weeks) developed significant chronic CAG, in which dietary walnuts significantly ameliorated chronic atrophic gastritis. Expressions of COX-2/PGE₂/NF-κB/c-Jun, elevated in 24 weeks control group, were all significantly decreased with walnut (p<0.01). Tumor suppressive enzyme, 15-PGDH, was significantly preserved with walnut. Control mice (36 weeks) all developed significant tumors accompanied with severe CAG. However, significantly decreased tumorigenesis was noted in group treated with walnuts, in which expressions of COX-2/PGE₂/NF-κB/IL-6/STAT3, all elevated in 36 weeks control group, were significantly decreased with walnut. Defensive proteins including HO-1, Nrf2, and SOCS-1 were significantly increased in walnut group. Proliferative index as marked with Ki-67 and PCNA was significantly regulated with walnut relevant to 15-PGDH preservation. Conclusively, walnut can be an anticipating nutritional intervention against H. pylori.