Plasma isoflavones and risk of primary liver cancer in Japanese women and men with hepatitis virus infection: a nested case-control study

Gut Microbiota-Assisted Synthesis, Cellular Interactions and Synergistic Perspectives of Equol as a Potent Anticancer Isoflavone

It is well known that, historically, plants have been an important resource of anticancer agents, providing several clinically approved drugs. Numerous preclinical studies have shown a strong anticancer potential of structurally different phytochemicals, including polyphenolic constituents of plants, flavonoids. In this review article, suppressing effects of equol in different carcinogenesis models are unraveled, highlighting the mechanisms involved in these anticancer activities. Among flavonoids, daidzein is a well-known isoflavone occurring in soybeans and soy products. In a certain part of population, this soy isoflavone is decomposed to equol under the action of gut microflora. Somewhat surprisingly, this degradation product has been shown to be more bioactive than its precursor daidzein, revealing a strong and multifaceted anticancer potential. In this way, it is important to bear in mind that the metabolic conversion of plant flavonoids might lead to products that are even more efficient than the parent compounds themselves, definitely deserving further studies.

LncRNA CARMN Affects Hepatocellular Carcinoma Prognosis by Regulating the miR-192-5p/LOXL2 Axis

Background. Hepatocellular carcinoma (HCC) is aggressive cancer with a poor prognosis. It has been suggested that the aberrant expression of LOXL2 is associated with the development of HCC, but the exact mechanism remains unclear. This research is aimed at examining the expression level and prognostic value of LOXL2 in hepatocellular carcinoma and its relationship with immune infiltration and at predicting its upstream noncoding RNAs (ncRNAs). Method. The transcriptome data of HCC was first downloaded from The Cancer Genome Atlas (TCGA) database to investigate the expression and prognosis of LOXL2. Then, the starBase database was used to find the upstream ncRNAs of LOXL2, and correlation analysis and expression analysis were performed. Finally, the Tumor Immune Estimation Resource (TIMER) was used to explore the association between LOXL2 and immune cell infiltration. Result. CARMN was considered to be the potential upstream lncRNA for the hsa-miR-192-5p/LOXL2 axis in HCC. Furthermore, the level LOXL2 was markedly positively associated with tumor immune cell infiltration and immune checkpoint expression in HCC. Conclusion. Higher expression of LOXL2 mediated by microRNA (miRNA) and long noncoding RNAs (lncRNA) is associated with poor overall survival (OS), immune infiltration, and immune checkpoint expression in HCC.

Neither soyfoods nor isoflavones warrant classification as endocrine disruptors: a technical review of the observational and clinical data

Soybeans are a rich source of isoflavones, which are classified as phytoestrogens. Despite numerous proposed benefits, isoflavones are often classified as endocrine disruptors, based primarily on animal studies. However, there are ample human data regarding the health effects of isoflavones. We conducted a technical review, systematically searching Medline, EMBASE, and the Cochrane Library (from inception through January 2021). We included clinical studies, observational studies, and systematic reviews and meta-analyses (SRMA) that examined the relationship between soy and/or isoflavone intake and endocrine-related endpoints. 417 reports (229 observational studies, 157 clinical studies and 32 SRMAs) met our eligibility criteria. The available evidence indicates that isoflavone intake does not adversely affect thyroid function. Adverse effects are also not seen on breast or endometrial tissue or estrogen levels in women, or testosterone or estrogen levels, or sperm or semen parameters in men. Although menstrual cycle length may be slightly increased, ovulation is not prevented. Limited insight could be gained about possible impacts of in utero isoflavone exposure, but the existing data are reassuring. Adverse effects of isoflavone intake were not identified in children, but limited research has been conducted. After extensive review, the evidence does not support classifying isoflavones as endocrine disruptors.

Validation of soy isoflavone intake and its health effects: a review of the development of exposure biomarkers

BACKGROUND/OBJECTIVES

It is difficult to consistently demonstrate the health effects of soy isoflavones owing to the multitude of factors contributing to their bioavailability. To accurately verify these health effects, dietary isoflavone intake should be measured using a biologically active dose rather than an intake dose. This concept has been expanded to the development of new exposure biomarkers in nutrition research. This review aims to provide an overview of the development of exposure biomarkers and suggest a novel research strategy for identifying the health effects of soy isoflavone intake.

MATERIALS/METHODS

We cover recent studies on the health effects of soy isoflavones focusing on isoflavone metabolites as exposure biomarkers.

RESULTS

Compared to non-fermented soy foods, fermented soy foods cause an increased concentration of isoflavones in the biofluid immediately following ingestion. The correlation between exposure biomarkers in blood and urine and the food frequency questionnaire was slightly lower than that of corresponding 24-h dietary recalls. Urinary and blood isoflavone levels did not show a consistent association with chronic disease and cancer risk.

CONCLUSION

It is crucial to understand the variable bioavailabilities of soy isoflavones, which may affect evaluations of soy isoflavone intake in health and disease. Further studies on the development of valid exposure biomarkers are needed to thoroughly investigate the health effects of isoflavone.

Comparison between the impact of fermented and unfermented soy intake on the risk of liver cancer: the JPHC Study

PURPOSE

The aim of this study was to compare the impact of fermented and unfermented soy intake, based on the following soy-derived products: tofu, soymilk, natto, and miso, on the risk of liver cancer among Japanese adults.

METHODS

75,089 Participants of the Japan Public Health Center-based Prospective Study (JPHC Study) were followed from the time of the 5-year follow-up questionnaire until the end of 2012-2013. Subjects with available data on hepatitis B virus (HBV) and hepatitis C virus (HCV) infection status from blood samples (n = 14,016) and those who were anti-HCV antibody (anti-HCV) or hepatitis B virus antigen (HBsAg) positive (n = 1033) were also analyzed separately. Cox proportional hazard models were employed to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs).

RESULTS

During 1,145,453 person-years, 534 newly diagnosed cases of liver cancer were identified in the JPHC Study. For miso intake among men, the multivariate-adjusted highest versus lowest quartile HR was 0.65 (95% CI, 0.48-0.89); p for trend = 0.006. Results were similar in those who were anti-HCV or HBsAg positive, 0.24 (0.08-0.70); p for trend = 0.004 highest versus lowest tertile. For the sub-analysis among only participants with known hepatitis infection status and HCV and HBsAg adjustment, a similar association was observed. In the multivariate complete cohort analysis, among women, the highest intake of fried tofu was inversely associated with the risk of liver cancer, HR = 0.45 (0.26-0.80); p for trend = 0.014.

CONCLUSIONS

We observed no association between total soy intake, fermented and unfermented, and risk of liver cancer, and only an inverse association between miso intake and liver cancer among men.

Effects of Isolated Isoflavones Intake on Health

BACKGROUND

Isoflavones are naturally occurring flavonoids, commonly found in the food consumed for centuries in the East-Asian population, characterized by a structure able to exert nonsteroidal estrogen-like activity on human cells. They have attracted researcher interest all around the word, following the results obtained in epidemiological and clinical studies. The involvement of isoflavones and their metabolites in various biological processes suggests that they can influence several metabolic pathways and can influence the gene expression at epigenetic level, involving effects that probably are due to early life exposure. They show positive health effects on several diseases, especially in the prevention of coronary heart and neurological diseases, hormone-related cancers, osteoporosis, and postmenopausal symptoms.

METHODS

We have performed a critical evaluation of available literature trough a structured search of bibliographic databases about isoflavones health promoting properties, risk assessment and mechanisms of action. In addition, we supplied useful information on their biochemical properties, sources and bioavailability.

RESULTS

Although these molecules have been the subjects of numerous researches, their role for the wellness of the human organism remains controversial. Moreover, there are substantial inconsistencies between the results obtained by epidemiologic studies conducted on Eastern population, which found high health promoting properties, and Western clinical trials, which found much less positive effects.

CONCLUSION

Further epidemiologic studies and well-designed prospective human studies are to determine the beneficial effects of isoflavones exposure, as well as establishing its safe therapeutic.

Effect of S-equol and Soy Isoflavones on Heart and Brain

BACKGROUND

Observational studies in Asia show that dietary intake of soy isoflavones had a significant inverse association with coronary heart disease (CHD). A recent randomized controlled trial (RCT) of soy isoflavones on atherosclerosis in the US, however, failed to show their benefit. The discrepancy may be due to the much lower prevalence of S-equol producers in Westerners: Only 20-30% of Westerners produce S-equol in contrast to 50-70% in Asians. S-equol is a metabolite of dietary soy isoflavone daidzein by gut microbiome and possesses the most antiatherogenic properties among all isoflavones. Several short-duration RCTs documented that soy isoflavones improves arterial stiffness. Accumulating evidence shows that both atherosclerosis and arterial stiffness are positively associated with cognitive decline/dementia. Therefore, potentially, soy isoflavones, especially S-equol, are protective against cognitive decline/dementia.

METHODS/RESULTS

This narrative review of clinical and epidemiological studies provides an overview of the health benefits of soy isoflavones and introduces S-equol. Second, we review recent evidence on the association of soy isoflavones and S-equol with CHD, atherosclerosis, and arterial stiffness as well as the association of atherosclerosis and arterial stiffness with cognitive decline/ dementia. Third, we highlight recent studies that report the association of soy isoflavones and S-equol with cognitive decline/dementia. Lastly, we discuss the future directions of clinical and epidemiological research on the relationship of S-equol and CHD and dementia.

CONCLUSIONS

Evidence from observational studies and short-term RCTs suggests that S-equol is anti-atherogenic and improves arterial stiffness and may prevent CHD and cognitive impairment/ dementia. Well-designed long-term (≥ 2years) RCTs should be pursued.

The relationship between urinary genistein levels and serum alanine aminotransferase levels in adults in the USA: National Health and Nutrition Examination Survey 1999-2010

BACKGROUND

Genistein, a phytoestrogen with similarities to female sex hormones, has been shown to protect against oxidative stress and fibrosis in nonalcoholic fatty liver injury in animal studies. However, few studies have examined genistein's effects on liver function in humans.

PARTICIPANTS AND METHODS

We analyzed data from the National Health and Nutrition Examination Survey from 1999 to 2010. Individuals younger than 21 years, with viral hepatitis, or with serum alanine aminotransferase (ALT) at the extremes of distribution (5% on each extreme) were excluded. Urinary genistein was normalized by urinary creatinine levels. The relationship between normalized urinary genistein (nUG) and serum ALT was examined using linear regression models with and without adjustment for potential confounders, and the differential effect of sex was examined using an interaction term.

RESULTS

Of the 9864 participants, 52% were female, 50% were White, 24% were elderly, 36% had hypertension, 12% had diabetes, and 8.1% were heavy alcohol drinkers. Serum ALT was significantly lower in the highest quartile compared with the lowest quartile of nUG (22.3 vs. 23.5 U/l; P<0.001). In adjusted models, individuals in the highest quartile had 0.75 U/l lower ALT levels than those in the lowest quartile (P=0.02). We found a significant difference in ALT levels between the lowest and highest quartiles of nUG in males, but not in females (difference in differences=1.77 U/l, interaction P=0.04).

CONCLUSION

We found a statistically significant association between higher nUG and lower serum ALT in males, but not in females. The sex-specific role of genistein in mitigating liver disease merits further study.

Time-dependent risks of cancer clustering among couples: a nationwide population-based cohort study in Taiwan

OBJECTIVES

Spousal clustering of cancer warrants attention. Whether the common environment or high-age vulnerability determines cancer clustering is unclear. The risk of clustering in couples versus non-couples is undetermined. The time to cancer clustering after the first cancer diagnosis is yet to be reported. This study investigated cancer clustering over time among couples by using nationwide data.

METHODS

A cohort of 5643 married couples in the 2002-2013 Taiwan National Health Insurance Research Database was identified and randomly matched with 5643 non-couple pairs through dual propensity score matching. Factors associated with clustering (both spouses with tumours) were analysed by using the Cox proportional hazard model.

RESULTS

Propensity-matched analysis revealed that the risk of clustering of all tumours among couples (13.70%) was significantly higher than that among non-couples (11.84%) (OR=1.182, 95% CI 1.058 to 1.321, P=0.0031). The median time to clustering of all tumours and of malignant tumours was 2.92 and 2.32 years, respectively. Risk characteristics associated with clustering included high age and comorbidity.

CONCLUSIONS

Shared environmental factors among spouses might be linked to a high incidence of cancer clustering. Cancer incidence in one spouse may signal cancer vulnerability in the other spouse. Promoting family-oriented cancer care in vulnerable families and preventing shared lifestyle risk factors for cancer are suggested.

Intake of Individual Flavonoids and Risk of Carcinogenesis: Overview of Epidemiological Evidence

Several epidemiological findings have demonstrated that specific flavonoids can be responsible for reduction of the risk of certain cancer types. However, these results are still rather limited, inconclusive and controversial. Therefore, in this comprehensive review article the findings reported to date about the associations between dietary intake of individual flavonoid compounds and cancer incidence are compiled and analyzed. Also, the possible reasons for inconsistencies are brought forth and discussed. As diet is a potentially modifiable factor in our behavioral choices, further large-scale prospective studies with longer follow-up times, different populations, various doses and exposure timing as well as diverse well-controlled confounders are highly needed to confirm or disprove the current epidemiological knowledge about the role of flavonoids on cancer risk. Regarding the promising data to date, more research on bioavailability, metabolism and biological action mechanisms of these plant secondary metabolites is also encouraged.

Synthesis and cytotoxicity evaluation of 3-amino-2-hydroxypropoxyisoflavone derivatives

Soy isoflavones exert a wide variety of biological activities, such as antioxidant, anti-inflammatory and anti-cancer properties. Nuclear factor erythroid 2-related factor 2 (Nrf2), a bZip transcription factor, plays a key role in soy isoflavones induced protection against oxidative stress and cancer. To obtain more effective isofavones, a series of 7,4'-bis-(3-amino-2-hydroxypropoxy), 7 or 4'-(3-amino-2-hydroxypropoxy) isoflavone derivatives have been synthesized as potential antitumor agents and Nrf2/ARE (antioxidant response element) activators. The cytotoxicity of these compounds in human cancer cell lines MDA-MB-231, HT-29, HCT116, HepG2 and 7402 was tested by MTT assay. In this study, the cytotoxicity of compound 3b exhibited highest cytotoxic activity and at the safety dose range, it also strongly up-regulated antioxidant response element (ARE)-luciferase reporter activity. In addition, compound 3b induced Nrf2 nuclear translocation and upregulated its downstream target genes NQO-1 and HO-1 at protein level. Taken together, our results suggest that compound 3b could be a potential agent for cancer themotherapy or cancer chemoprevention.

Genistein and cancer: current status, challenges, and future directions

Primary prevention through lifestyle interventions is a cost-effective alternative for preventing a large burden of chronic and degenerative diseases, including cancer, which is one of the leading causes of morbidity and mortality worldwide. In the past decade, epidemiologic and preclinical evidence suggested that polyphenolic phytochemicals present in many plant foods possess chemopreventive properties against several cancer forms. Thus, there has been increasing interest in the potential cancer chemopreventive agents obtained from natural sources, such as polyphenols, that may represent a new, affordable approach to curb the increasing burden of cancer throughout the world. Several epidemiologic studies showed a relation between a soy-rich diet and cancer prevention, which was attributed to the presence of a phenolic compound, genistein, present in soy-based foods. Genistein acts as a chemotherapeutic agent against different types of cancer, mainly by altering apoptosis, the cell cycle, and angiogenesis and inhibiting metastasis. Targeting caspases, B cell lymphoma 2 (Bcl-2)-associated X protein (Bax), Bcl-2, kinesin-like protein 20A (KIF20A), extracellular signal-regulated kinase 1/2 (ERK1/2), nuclear transcription factor κB (NF-κB), mitogen-activated protein kinase (MAPK), inhibitor of NF-κB (IκB), Wingless and integration 1 β-catenin (Wnt/β-catenin), and phosphoinositide 3 kinase/Akt (PI3K/Akt) signaling pathways may act as the molecular mechanisms of the anticancer, therapeutic effects of genistein. Genistein also shows synergistic behavior with well-known anticancer drugs, such as adriamycin, docetaxel, and tamoxifen, suggesting a potential role in combination therapy. This review critically analyzes the available literature on the therapeutic role of genistein on different types of cancer, focusing on its chemical features, plant food sources, bioavailability, and safety.