Can soy phytoestrogens decrease DNA methylation in BRCA1 and BRCA2 oncosuppressor genes in breast cancer?

Plant-Based Anticancer Compounds With a Focus on Breast Cancer

Breast cancer is a common form of cancer among women characterized by the growth of malignant cells in the breast tissue. The most common treatments for this condition include chemotherapy, surgical intervention, radiation therapy, hormone therapy, and biological therapy. The primary issues associated with chemotherapy and radiation therapy are their adverse events and significant financial burden among patients in underdeveloped countries. This highlights the need to explore and develop superior therapeutic options that are less detrimental and more economically efficient. Plants provide an abundant supply of innovative compounds and present a promising new avenue for investigating cancer. Plants and their derivations are undergoing a revolution due to their reduced toxicity, expediency, cost-effectiveness, safety, and simplicity in comparison to conventional treatment methods. Natural products are considered promising candidates for the development of anticancer drugs, due perhaps to the diverse pleiotropic effects on target events. The effects of plant-derived products are limited to cancer cells while leaving healthy cells unaffected. Identification of compounds with strong anticancer properties and development of plant-based medications for cancer treatment might be crucial steps in breast cancer therapy. Although bioactive compounds have potent anticancer properties, they also have drawbacks that need to be resolved before their application in clinical trials and improved for the approved drugs. This study aims to give comprehensive information on known anticancer compounds, including their sources and molecular mechanisms of actions, along with opportunities and challenges in plant-based anticancer therapies.

S100A8 and S100A12 Proteins as Biomarkers of High Disease Activity in Patients with Rheumatoid Arthritis That Can Be Regulated by Epigenetic Drugs

Rheumatoid arthritis (RA) is an autoimmune chronic inflammatory disease that is still not well understood in terms of its pathogenesis and presents diagnostic and therapeutic challenges. Monocytes are key players in initiating and maintaining inflammation through the production of pro-inflammatory cytokines and S100 proteins in RA. This study aimed to test a specific DNA methylation inhibitor (RG108) and activator (budesonide) in the regulation of pro-inflammatory mediators-especially the S100 proteins. We also searched for new biomarkers of high disease activity in RA patients. RNA sequencing analysis of healthy controls (HCs) and RA monocytes was performed. Genes such as the S100 family, TNF, and IL-8 were validated by qRT-PCR following DNA-methylation-targeted drug treatment in a monocytic THP-1 cell line. The concentrations of the S100A8, S100A11, and S100A12 proteins in the sera and synovial fluids of RA patients were tested and correlated with clinical parameters. We demonstrated that RA monocytes had significantly increased levels of S100A8, S100A9, S100A11, S100A12, MYD88, JAK3, and IQGAP1 and decreased levels of IL10RA and TGIF1 transcripts. In addition, stimulation of THP-1 cells with budesonide statistically reduced the expression of the S100 family, IL-8, and TNF genes. In contrast, THP-1 cells treated with RG108 had increased levels of the S100 family and TNF genes. We also revealed a significant upregulation of S100A8, S100A11, and S100A12 in RA patients, especially in early RA compared to HC sera. In addition, protein levels of S100A8, S100A11, and S100A12 in RA synovial fluids compared to HC sera were significantly increased. Overall, our data suggest that the S100A8 and S100A12 proteins are strongly elevated during ongoing inflammation, so they could be used as a better biomarker of disease activity than CRP. Interestingly, epigenetic drugs can regulate these S100 proteins, suggesting their potential use in targeting RA inflammation.

Role of Medicinal plant-derived Nutraceuticals as a potential target for the treatment of breast cancer

Breast cancer (BC) is one of the most challenging cancers to treat, accounting for many cancer-related deaths. Over some years, chemotherapy, hormone treatment, radiation, and surgeries have been used to treat cancer. Unfortunately, these treatment options are unsuccessful due to crucial adverse reactions and multidrug tolerance/resistance. Although it is clear that substances in the nutraceuticals category have a lot of anti-cancer activity, using a supplementary therapy strategy, in this case, could be very beneficial. Nutraceuticals are therapeutic agents, which are nutrients that have drug-like characteristics and can be used to treat diseases. Plant nutraceuticals categorized into polyphenols, terpenoids, vitamins, alkaloids, and flavonoids are part of health food products, that have great potential for combating BC. Nutraceuticals can reduce BC's severity, limit malignant cell growth, and modify cancer-related mechanisms. Nutraceuticals acting by attenuating Hedgehog, Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), Notch, and Wnt/β-catenin signaling are the main pathways in controlling the self-renewal of breast cancer stem cells (BCSCs). This article reviews some important nutraceuticals and their modes of action, which can be very powerful versus BC. PRACTICAL APPLICATIONS: Nutraceuticals' importance to the control and diagnosis of breast cancer is undeniable and cannot be overlooked. Natural dietary compounds have a wide range of uses and have been used in traditional medicine. In addition, these natural chemicals can enhance the effectiveness of other traditional medicines. They may also be used as a treatment process independently because of their capacity to affect several cancer pathways. This study highlights a variety of natural chemicals, and their mechanisms of action, routes, synergistic effects, and future potentials are all examined.

Intracellular CYTL1, a novel tumor suppressor, stabilizes NDUFV1 to inhibit metabolic reprogramming in breast cancer

Loss-of-function mutations frequently occur in tumor suppressor genes, i.e., p53, during the malignant progression of various cancers. Whether any intrinsic suppressor carries a rare mutation is largely unknown. Here, we demonstrate that intracellular cytokine-like protein 1 (CYTL1) plays a key role in preventing the robust glycolytic switching characteristic of breast cancer. A low intracellular CYTL1 level, not its mutation, is required for metabolic reprogramming. Breast cancer cells expressing an intracellular form of CYTL1 lacking a 1-22 aa signal peptide, ΔCYTL1, show significantly attenuated glucose uptake and lactate production, which is linked to the inhibition of cell growth and metastasis in vitro and in vivo. Mechanistically, CYTL1 competitively binds the N-terminal sequence of NDUFV1 to block MDM2-mediated degradation by the proteasome, leading to the stability of the NDUFV1 protein. In addition to inducing increased NAD⁺ levels, NDUFV1 interacts with Src to attenuate LDHA phosphorylation at tyrosine 10 and reduce lactate production. Our results reveal, for the first time, that CYTL1 is a novel tumor suppressor. Its function in reversing metabolic reprogramming toward glycolysis may be very important for the development of novel antitumor strategies.

Dietary Phytoestrogens and Their Metabolites as Epigenetic Modulators with Impact on Human Health

The impact of dietary phytoestrogens on human health has been a topic of continuous debate since their discovery. Nowadays, based on their presumptive beneficial effects, the amount of phytoestrogens consumed in the daily diet has increased considerably worldwide. Thus, there is a growing need for scientific data regarding their mode of action in the human body. Recently, new insights of phytoestrogens’ bioavailability and metabolism have demonstrated an inter-and intra-population heterogeneity of final metabolites’ production. In addition, the phytoestrogens may have the ability to modulate epigenetic mechanisms that control gene expression. This review highlights the complexity and particularity of the metabolism of each class of phytoestrogens, pointing out the diversity of their bioactive gut metabolites. Futhermore, it presents emerging scientific data which suggest that, among well-known genistein and resveratrol, other phytoestrogens and their gut metabolites can act as epigenetic modulators with a possible impact on human health. The interconnection of dietary phytoestrogens’ consumption with gut microbiota composition, epigenome and related preventive mechanisms is discussed. The current challenges and future perspectives in designing relevant research directions to explore the potential health benefits of dietary phytoestrogens are also explored.

Flavonoids Overcome Drug Resistance to Cancer Chemotherapy by Epigenetically Modulating Multiple Mechanisms

Drug resistance is the major reason accounting for the treatment failure in cancer chemotherapy. Dysregulation of the epigenetic machineries is known to induce chemoresistance. It was reported that numerous genes encoding the key mediators in cancer proliferation, apoptosis, DNA repair, and drug efflux are dysregulated in resistant cancer cells by aberrant DNA methylation. The imbalance of various enzymes catalyzing histone post-translational modifications is also known to alter chromatin configuration and regulate multiple drug resistance genes. Alteration in miRNA signature in cancer cells also gives rise to chemoresistance. Flavonoids are a large group of naturally occurring polyphenolic compounds ubiquitously found in plants, fruits, vegetables and traditional herbs. There has been increasing research interest in the health-promoting effects of flavonoids. Flavonoids were shown to directly kill or re-sensitize resistant cancer cells to conventional anticancer drugs by epigenetic mechanisms. In this review, we summarize the current findings of the circumvention of drug resistance by flavonoids through correcting the aberrant epigenetic regulation of multiple resistance mechanisms. More investigations including the evaluation of synergistic anticancer activity, dosing sequence effect, toxicity in normal cells, and animal studies, are warranted to establish the full potential of the combination of flavonoids with conventional chemotherapeutic drugs in the treatment of cancer with drug resistance.

Epigenetic Regulation and Dietary Control of Triple Negative Breast Cancer

Triple negative breast cancer (TNBC) represents a highly heterogeneous group of breast cancers, lacking expression of the estrogen (ER) and progesterone (PR) receptors, and human epidermal growth factor receptor 2 (HER2). TNBC are characterized by a high level of mutation and metastasis, poor clinical outcomes and overall survival. Here, we review the epigenetic mechanisms of regulation involved in cell pathways disrupted in TNBC, with particular emphasis on dietary food components that may be exploited for the development of effective strategies for management of TNBC.

Caffeic acid phenethyl ester, a coffee polyphenol, inhibits DNA methylation in vitro and in vivo

DNA methylation represents an important epigenetic regulation of the genome. Earlier studies have suggested that dietary phenolic compounds including those contained in coffee, tea and soy products may modulate the level of DNA methylation. In this study, we first characterize the effect of caffeic acid phenethyl ester (CAPE) and other dietary phenolic compounds on DNA methylation in vitro. The IC₅₀ values of CAPE, daidzein, isorhamnetin and genistein are 7.6, 6.9, 6.2, and 4.3 μM, respectively, in an in-vitro enzymatic assay system. Computational analysis indicates that CAPE, daidzein, isorhamnetin and genistein can bind inside the DNA substrate-binding site in human DNMT1 with a favorable binding energy. In an animal study, we find that maternal CAPE treatment shifts the coat color distribution of the 21-day-old A^vy/a offspring towards the yellow phenotype, indicating that CAPE inhibits the methylation of the agouti gene promoter sequence in vivo. The results from this study may shed light on the potential epigenetic effect in the offspring resulting from maternal intake of certain coffee phenolics during pregnancy.

Special bioactive compounds and functional foods may exhibit neuroprotective effects in patients with dementia (Review)

Dementia is a failure of cognitive ability characterized by severe neurodegeneration in select neural systems, and Alzheimer's disease (AD) is the most common type of neurodegenerative disease. Although numerous studies have provided insights into the pathogenesis of AD, the underlying signaling and molecular pathways mediating the progressive decline of cognitive function remain poorly understood. Recent progress in molecular biology has provided an improved understanding of the importance of molecular pathogenesis of AD, and has proposed an association between DNA repair mechanisms and AD. In particular, the fundamental roles of phosphatase and tensin homologue deleted on chromosome 10 (PTEN) and breast cancer gene 1 (BRCA1) tumor suppressors have been shown to regulate the pathogenesis of neurodegeneration. Consequently, onset of neurodegenerative diseases may be deferred with the use of dietary neuroprotective agents which alter the signaling mediated by the aforementioned tumor suppressors. In a healthy neuron, homeostasis of key intracellular molecules is of great importance, and preventing neuronal apoptosis is one of the primary goals of treatments designed for dementia-associated diseases. In the present review, progress into the understanding of dietary regulation for preventing or limiting development of dementia is discussed with a focus on the modulatory roles of PTEN and BRCA1 signaling.

Flavonoids and Other Polyphenols Act as Epigenetic Modifiers in Breast Cancer

Breast cancer is a common cancer that occurs due to different epigenetic alterations and genetic mutations. Various epidemiological studies have demonstrated an inverse correlation between breast cancer incidence and flavonoid intake. The anti-cancer action of flavonoids, a class of polyphenolic compounds that are present in plants, as secondary metabolites has been a major topic of research for many years. Our review analysis demonstrates that flavonoids exhibit anti-cancer activity against breast cancer occurring in different ethnic populations. Breast cancer subtype and menopausal status are the key factors in inducing the flavonoid's anti-cancer action in breast cancer. The dose is another key factor, with research showing that approximately 10 mg/day of isoflavones is required to inhibit breast cancer occurrence. In addition, flavonoids also influence the epigenetic machinery in breast cancer, with research demonstrating that epigallocatechin, genistein, and resveratrol all inhibited DNA methyltransferase and altered chromatin modification in breast cancer. These flavonoids can induce the expression of different tumor suppressor genes that may contribute to decreasing breast cancer progression and metastasis. Additional studies are required to confirm the contribution of epigenetic modifications by flavonoids to breast cancer prevention.

Genistein Enhances Radiosensitivity of Human Hepatocellular Carcinoma Cells by Inducing G2/M Arrest and Apoptosis

New radiosensitizers are urgently needed for radiation therapy patients with localized hepatocellular carcinoma (HCC) that is refractory to radical surgery. We previously found that genistein, a major soy isoflavone, exerts radioprotective effects on L-02 normal liver cells at low concentrations. Here, we report that 5 µM genistein shows less harm to L-02 cells than HCC cells and that it significantly enhances the radiosensitivity of HCC cells by enhancing DNA damage, chromosomal aberrations and cell cycle arrest at G₂/M phase and by exacerbating apoptosis. Mechanistically, genistein aggravates X-ray-induced decreases in the levels of phospho-Bad (Ser136) but enhances the levels of phospho-Chk2 (Thr68), phospho-ATM (Ser1981) and γ-H2AX. Micro-array analysis indicated that downregulation of POU6F and CCNE2 expression and upregulation of FBXO32 and cyclin B1 expression might play vital roles in genistein-induced radiosensitivity. These findings suggest genistein as an interesting candidate for adjuvant radiotherapy for HCC and indicate that genistein causes less harm to normal cells than HCC cells by inducing G₂/M arrest and apoptosis.

The Promises and Challenges of Toxico-Epigenomics: Environmental Chemicals and Their Impacts on the Epigenome

BACKGROUND

It has been estimated that a substantial portion of chronic and noncommunicable diseases can be caused or exacerbated by exposure to environmental chemicals. Multiple lines of evidence indicate that early life exposure to environmental chemicals at relatively low concentrations could have lasting effects on individual and population health. Although the potential adverse effects of environmental chemicals are known to the scientific community, regulatory agencies, and the public, little is known about the mechanistic basis by which these chemicals can induce long-term or transgenerational effects. To address this question, epigenetic mechanisms have emerged as the potential link between genetic and environmental factors of health and disease.

OBJECTIVES

We present an overview of epigenetic regulation and a summary of reported evidence of environmental toxicants as epigenetic disruptors. We also discuss the advantages and challenges of using epigenetic biomarkers as an indicator of toxicant exposure, using measures that can be taken to improve risk assessment, and our perspectives on the future role of epigenetics in toxicology.

DISCUSSION

Until recently, efforts to apply epigenomic data in toxicology and risk assessment were restricted by an incomplete understanding of epigenomic variability across tissue types and populations. This is poised to change with the development of new tools and concerted efforts by researchers across disciplines that have led to a better understanding of epigenetic mechanisms and comprehensive maps of epigenomic variation. With the foundations now in place, we foresee that unprecedented advancements will take place in the field in the coming years. https://doi.org/10.1289/EHP6104.

Epigenetic Activation of BRCA1 by Genistein In Vivo and Triple Negative Breast Cancer Cells Linked to Antagonism toward Aryl Hydrocarbon Receptor

Triple negative breast cancers (TNBC) are the most aggressive and lethal breast cancers (BC). The aryl hydrocarbon receptor (AHR) is often overexpressed in TNBC, and its activation results in the epigenetic silencing of BRCA1, which is a necessary factor for the transcriptional activation of estrogen receptor (ER)α. The dietary isoflavone genistein (GEN) modulates BRCA1 CpG methylation in BC cells. The purpose of this study was to investigate the effect of GEN on BRCA1 epigenetic regulation and AHR activity in vivo and TNBC cells. Mice were administered a control or GEN-enriched (4 and 10 ppm) diet from gestation through post-natal day 50. Mammary tissue was analyzed for changes in BRCA1 regulation and AhR activity. TNBC cells with constitutively hypermethylated BRCA1 (HCC38) and MCF7 cells were used. Protein levels and mRNA expression were measured by Western blot and real-time PCR, respectively. BRCA1 promoter occupancy and CpG methylation were analyzed by chromatin immunoprecipitation and methylation-specific PCR, respectively. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. GEN administered in the diet dose-dependently decreased basal Brca1 methylation and AHR activity in the mammary gland of adult mice. HCC38 cells were found to overexpress constitutively active AHR in parallel with BRCA1 hypermethylation. The treatment of HCC38 cells with GEN upregulated BRCA1 protein levels, which was attributable to decreased CpG methylation and AHR binding at BRCA1 exon 1a. In MCF7 cells, GEN prevented the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-dependent localization of AHR at the BRCA1 gene. These effects were consistent with those elicited by control AHR antagonists galangin (GAL), CH-223191, and α-naphthoflavone. The pre-treatment with GEN sensitized HCC38 cells to the antiproliferative effects of 4-hydroxytamoxifen. We conclude that the dietary compound GEN may be effective for the prevention and reversal of AHR-dependent BRCA1 hypermethylation, and the restoration of ERα-mediated response, thus imparting the sensitivity of TNBC to antiestrogen therapy.

Dietary Compounds as Epigenetic Modulating Agents in Cancer

Epigenetic mechanisms control gene expression during normal development and their aberrant regulation may lead to human diseases including cancer. Natural phytochemicals can largely modulate mammalian epigenome through regulation of mechanisms and proteins responsible for chromatin remodeling. Phytochemicals are mainly contained in fruits, seeds, and vegetables as well as in foods supplements. These compounds act as powerful cellular antioxidants and anti-carcinogens agents. Several dietary compounds such as catechins, curcumin, genistein, quercetin and resveratrol, among others, exhibit potent anti-tumor activities through the reversion of epigenetic alterations associated to oncogenes activation and inactivation of tumor suppressor genes. In this review, we summarized the actual knowledge about the role of dietary phytochemicals in the restoration of aberrant epigenetic alterations found in cancer cells with a particular focus on DNA methylation and histone modifications. Furthermore, we discussed the mechanisms by which these natural compounds modulate gene expression at epigenetic level and described their molecular targets in diverse types of cancer. Modulation of epigenetic activities by phytochemicals will allow the discovery of novel biomarkers for cancer prevention, and highlights its potential as an alternative therapeutic approach in cancer.

Natural Products and Chemical Biology Tools: Alternatives to Target Epigenetic Mechanisms in Cancers

DNA methylation and histone acetylation are widely studied epigenetic modifications. They are involved in numerous pathologies such as cancer, neurological disease, inflammation, obesity, etc. Since the discovery of the epigenome, numerous compounds have been developed to reverse DNA methylation and histone acetylation aberrant profile in diseases. Among them several were inspired by Nature and have a great interest as therapeutic molecules. In the quest of finding new ways to target epigenetic mechanisms, the use of chemical tools is a powerful strategy to better understand epigenetic mechanisms in biological systems. In this review we will present natural products reported as DNMT or HDAC inhibitors for anticancer treatments. We will then discuss the use of chemical tools that have been used in order to explore the epigenome.

Exploratory analysis of the human breast DNA methylation profile upon soymilk exposure

Upon soy consumption, isoflavone metabolites attain bioactive concentrations in breast tissue possibly affecting health. Though in vitro epigenetic activity of soy metabolites has been described, the in vivo impact on the epigenome is largely unknown. Therefore, in this case-control study, the breast glandular tissue DNA methylome was explored in women undergoing an aesthetic breast reduction. After a run-in phase, 10 generally healthy Belgian or Dutch women received soymilk for 5 days. MethylCap-seq methylation profiles were compared with those of 10 matched controls. Isoflavones and their microbial metabolites were quantified in urine, serum, and glandular breast tissue (liquid chromatography-mass spectrometry) and 17β-estradiol in glandular breast tissue (immunoassay). Global DNA methylation levels were obtained for 6 cases and 5 controls using liquid chromatography-mass spectrometry. Although lower MethylCap-seq coverages were observed, mass spectrometry results and computational LINE-1 methylation analysis did not provide evidence supporting global methylation alterations upon treatment. At a false discovery rate of 0.05, no differentially methylated loci were identified. Moreover, a set of previously identified loci was specifically tested, but earlier reported results could not be validated. In conclusion, after a 5-day soymilk treatment, no major general epigenetic reprogramming in breast tissue could be found in this exploratory study.

Phytoestrogens and mycoestrogens interacting with breast cancer proteins

Breast cancer is a highly heterogeneous disease influenced by the hormonal microenvironment and the most common malignancy in women worldwide. Some phytoestrogens and mycoestrogens have been epidemiologically linked as risk factors or protectors, however their mechanisms of action are complex and not fully understood. The aim of this study was to predict the potential of 36 natural xenoestrogens to interact with 189 breast cancer proteins using AutoDock Vina. In order to validate our protocol, an in silico docking pose and binding site determination was compared with the crystallographic structure and the power of prediction to distinguish between ligand and decoys was evaluated through a receiver operating characteristic curve (ROC) of the resultant docking affinities and in vitro data. The best affinity score was obtained for glyceollin III interacting with the sex hormone binding globulin (-11.9 Kcal/mol), a plasma steroid transport protein that regulates sex steroids bioavailability. Other natural xenoestrogens such as beta-carotene, chrysophanol 8-O-beta-d-glucopyranoside and glyceollin I, also presented good affinity for proteins related to this disease and the validation was successful. This study may help to prioritize compounds for toxicity tests or drug development from natural scaffolds, and to elucidate their mechanisms of action.

Epigenetics of breast cancer: Modifying role of environmental and bioactive food compounds

SCOPE

Reduced expression of tumor suppressor genes (TSG) increases the susceptibility to breast cancer. However, only a small percentage of breast tumors is related to family history and mutational inactivation of TSG. Epigenetics refers to non-mutational events that alter gene expression. Endocrine disruptors found in foods and drinking water may disrupt epigenetically hormonal regulation and increase breast cancer risk. This review centers on the working hypothesis that agonists of the aromatic hydrocarbon receptor (AHR), bisphenol A (BPA), and arsenic compounds, induce in TSG epigenetic signatures that mirror those often seen in sporadic breast tumors. Conversely, it is hypothesized that bioactive food components that target epigenetic mechanisms protect against sporadic breast cancer induced by these disruptors.

METHODS AND RESULTS

This review highlights (i) overlaps between epigenetic signatures placed in TSG by AHR-ligands, BPA, and arsenic with epigenetic alterations associated with sporadic breast tumorigenesis; and (ii) potential opportunities for the prevention of sporadic breast cancer with food components that target the epigenetic machinery.

CONCLUSIONS

Characterizing the overlap between epigenetic signatures elicited in TSG by endocrine disruptors with those observed in sporadic breast tumors may afford new strategies for breast cancer prevention with specific bioactive food components or diet.

DUSP1 promoter methylation in peripheral blood leukocyte is associated with triple-negative breast cancer risk

DNA methylation is one of the most common epigenetic alterations, providing important information regarding cancer risk and prognosis. A case-control study (423 breast cancer cases, 509 controls) and a case-only study (326 cases) were conducted to evaluate the association of DUSP1 promoter methylation with breast cancer risk and clinicopathological characteristics. No significant association between DUSP1 methylation in peripheral blood leukocyte (PBL) DNA and breast cancer risk was observed. DUSP1 methylation was significantly associated with ER/PR-negative status; in particular, triple-negative breast cancer patients showed the highest frequency of DUSP1 methylation in both tumour DNA and PBL DNA. Soybean intake was significantly correlated with methylated DUSP1 only in ER-negative (OR 2.978; 95% CI 1.245-7.124) and PR negative (OR 2.735; 95% CI 1.315-5.692) patients. Irregular menstruation was significantly associated with methylated DUSP1 only in ER-positive (OR 3.564; 95% CI 1.691-7.511) and PR-positive (OR 3.902, 95% CI 1.656-9.194) patients. Thus, DUSP1 methylation is a cancer-associated hypermethylation event that is closely linked with triple-negative status. Further investigations are warranted to confirm the association of environmental factors, including fruit and soybean intake, irregular menstruation, and ER/PR status, with DUSP1 methylation in breast tumour DNA.

Botanicals and Their Bioactive Phytochemicals for Women's Health

Botanical dietary supplements are increasingly popular for women's health, particularly for older women. The specific botanicals women take vary as a function of age. Younger women will use botanicals for urinary tract infections, especially Vaccinium macrocarpon (cranberry), where there is evidence for efficacy. Botanical dietary supplements for premenstrual syndrome (PMS) are less commonly used, and rigorous clinical trials have not been done. Some examples include Vitex agnus-castus (chasteberry), Angelica sinensis (dong quai), Viburnum opulus/prunifolium (cramp bark and black haw), and Zingiber officinale (ginger). Pregnant women have also used ginger for relief from nausea. Natural galactagogues for lactating women include Trigonella foenum-graecum (fenugreek) and Silybum marianum (milk thistle); however, rigorous safety and efficacy studies are lacking. Older women suffering menopausal symptoms are increasingly likely to use botanicals, especially since the Women's Health Initiative showed an increased risk for breast cancer associated with traditional hormone therapy. Serotonergic mechanisms similar to antidepressants have been proposed for Actaea/Cimicifuga racemosa (black cohosh) and Valeriana officinalis (valerian). Plant extracts with estrogenic activities for menopausal symptom relief include Glycine max (soy), Trifolium pratense (red clover), Pueraria lobata (kudzu), Humulus lupulus (hops), Glycyrrhiza species (licorice), Rheum rhaponticum (rhubarb), Vitex agnus-castus (chasteberry), Linum usitatissimum (flaxseed), Epimedium species (herba Epimedii, horny goat weed), and Medicago sativa (alfalfa). Some of the estrogenic botanicals have also been shown to have protective effects against osteoporosis. Several of these botanicals could have additional breast cancer preventive effects linked to hormonal, chemical, inflammatory, and/or epigenetic pathways. Finally, although botanicals are perceived as natural safe remedies, it is important for women and their healthcare providers to realize that they have not been rigorously tested for potential toxic effects and/or drug/botanical interactions. Understanding the mechanism of action of these supplements used for women's health will ultimately lead to standardized botanical products with higher efficacy, safety, and chemopreventive properties.

Regulation of miR-200c and miR-141 by Methylation in Prostate Cancer

BACKGROUND

In prostate cancer (PCa), abnormal expression of several microRNAs (miRNAs) has been previously reported. Increasing evidence shows that aberrant epigenetic regulation of miRNAs is a contributing factor to their altered expression in cancer. In this study, we investigate whether expression of miR-200c and miR-141 in PCa is related to the DNA methylation status of their promoter.

METHODS

PCR analysis of miR-200c and miR-141, and CpG methylation analysis of their common promoter, was performed in PCa cell-lines and in archived prostate biopsy specimens. The biological significance of miR-200c and miR-141 expression in prostate cancer cells was assessed by a series of in vitro bioassays and the effect on proposed targets DNMT3A and TET1/TET3 was investigated. The effect on promoter methylation status in cells treated with demethylating agents was also examined.

RESULTS

miR-200c and miR-141 are both highly elevated in LNCaP, 22RV1, and DU145 cells, but significantly reduced in PC3 cells. This correlates inversely with the methylation status of the miR-200c/miR-141 promoter, which is unmethylated in LNCaP, 22RV1, and DU145 cells, but hypermethylated in PC3. In PC3 cells, miR-200c and miR-141 expression is subsequently elevated by treatment with the demethylating drug decitabine (5-aza-2'deoxycytidine) and by knockdown of DNA methyltransferase 1 (DNMT1), suggesting their expression is regulated by methylation. Expression of miR-200c and miR-141 in prostate biopsy tissue was inversely correlated with methylation in promoter CpG sites closest to the miR-200c/miR-141 loci. In vitro, over-expression of miR-200c in PC3 cells inhibited growth and clonogenic potential, as well as inducing apoptosis. Expression of the genes DNMT3A and TET1/TET3 were down-regulated by miR-200c and miR-141 respectively. Finally, treatment with the soy isoflavone genistein caused demethylation of the promoter CpG sites closest to the miR-200c/miR-141 loci resulting in increased miR-200c expression.

CONCLUSIONS

Our findings provide evidence that miR-200c and miR-141 are under epigenetic regulation in PCa cells. We propose that profiling their expression and methylation status may have potential as a novel biomarker or focus of therapeutic intervention in the diagnosis and prognosis of PCa. Prostate 76:1146-1159, 2016. © 2016 Wiley Periodicals, Inc.

Soybean isoflavones attenuate the expression of genes related to endometrial cancer risk

OBJECTIVE

We evaluated whether genistein or estrogen treatment has the same effect when administered immediately or late to rats induced with menopause using ovariectomy.

METHODS

Sixty adult female rats were divided into six treatment groups: GI = vehicle immediately after ovariectomy; GII = vehicle 30 days after ovariectomy; GIII = genistein immediately after ovariectomy; GIV = genistein 30 days after ovariectomy; GV = estrogen immediately after ovariectomy; and GVI = estrogen 30 days after ovariectomy. All animals were treated for 30 consecutive days. At the end of the treatment, part of the uteri was removed for subsequent histological studies and another part was used to evaluate estrogen receptors 1 and 2, cell proliferation (cyclin A1 and A2, cyclin D1, cyclin-dependent kinase inhibitors 1, 1B and 2, antigen identified by the monoclonal antibody Ki67) and angiogenesis (vascular endothelial growth factor, VEGF-A) gene expression.

RESULTS

Late treatment after castration in rats resulted in more developed endometrium, enhanced cell proliferation and estrogen-signalling pathways, particularly the cyclin-related genes Ki67 and VEGF-A, compared to early treatment. Interestingly, these same effects were less intense with genistein compared to those induced by estrogen, especially when genistein was administered late.

CONCLUSION

Our data show that isoflavone renders a lower risk of cancer when compared to estrogen in treatments.

BRCA1 and p53 tumor suppressor molecules in Alzheimer's disease

Tumor suppressor molecules play a pivotal role in regulating DNA repair, cell proliferation, and cell death, which are also important processes in the pathogenesis of Alzheimer’s disease. Alzheimer’s disease is the most common neurodegenerative disorder, however, the precise molecular events that control the death of neuronal cells are unclear. Recently, a fundamental role for tumor suppressor molecules in regulating neurons in Alzheimer’s disease was highlighted. Generally, onset of neurodegenerative diseases including Alzheimer’s disease may be delayed with use of dietary neuro-protective agents against oxidative stresses. Studies suggest that dietary antioxidants are also beneficial for brain health in reducing disease-risk and in slowing down disease-progression. We summarize research advances in dietary regulation for the treatment of Alzheimer’s disease with a focus on its modulatory roles in BRCA1 and p53 tumor suppressor expression, in support of further therapeutic research in this field.

Hypothesis: Activation of rapid signaling by environmental estrogens and epigenetic reprogramming in breast cancer

Environmental and lifestyle factors are considered significant components of the increasing breast cancer risk in the last 50 years. Specifically, exposure to environmental endocrine disrupting compounds is correlated with cancer susceptibility in a variety of tissues. In both human and rodent models, the exposure to ubiquitous environmental estrogens during early life has been shown to disrupt normal mammary development and cause permanent adverse effects. Recent studies indicate that environmental estrogens not only have the ability to disrupt estrogen receptor (ER) signaling, but can also reprogram the epigenome by altering DNA and histone methylation through rapid, nongenomic ER actions. We have observed xenoestrogen-mediated activation of several nongenomic signaling pathways and have identified a target for epigenetic reprogramming in MCF-7 breast cancer cells. These observations, in addition to data from the literature, support the hypothesis that activation of rapid signaling by environmental estrogens can lead to epigenetic reprogramming and contribute to the progression of breast cancer.

Impact of soy isoflavones on the epigenome in cancer prevention

Isoflavones (IF) such as genistein are cancer preventive phytochemicals found in soy and other legumes. Epidemiological studies point to a reduced risk for hormone‑dependent cancers in populations following a typical Asian diet rich in soy products. IF act as phytoestrogens and prevent tumorigenesis in rodent models by a broad spectrum of bioactivities. During the past 10 years, IF were shown to target all major epigenetic mechanisms regulating gene expression, including DNA methylation, histone modifications controlling chromatin accessibility, and non-coding RNAs. These effects have been suggested to contribute to cancer preventive potential in in vitro and in vivo studies, affecting several key processes such as DNA repair, cell signaling cascades including Wnt-signaling, induction of apoptosis, cell cycle progression, cell proliferation, migration and invasion, epithelial-mesenchymal transition (EMT), metastasis formation and development of drug-resistance. We here summarize the state-of-the-art of IF affecting the epigenome in major hormone-dependent, urogenital, and gastrointestinal tumor types and in in vivo studies on anti-cancer treatment or developmental aspects, and short-term intervention studies in adults. These data, while often requiring replication, suggest that epigenetic gene regulation represents an important novel target of IF and should be taken into consideration when evaluating the cancer preventive potential of IF in humans.

Phytoestrogens and prevention of breast cancer: The contentious debate

Phytoestrogens have multiple actions within target cells, including the epigenome, which could be beneficial to the development and progression of breast cancer. In this brief review the action of phytoestrogens on oestrogen receptors, cell signalling pathways, regulation of the cell cycle, apoptosis, steroid synthesis and epigenetic events in relation to breast cancer are discussed. Phytoestrogens can bind weakly to oestrogen receptors (ERs) and some have a preferential affinity for ERβ which can inhibit the transcriptional growth-promoting activity of ERα. However only saturating doses of phytoestrogens, stimulating both ERα and β, exert growth inhibitory effects. Such effects on growth may be through phytoestrogens inhibiting cell signalling pathways. Phytoestrogens have also been shown to inhibit cyclin D1 expression but increase the expression of cyclin-dependent kinase inhibitors (p21 and p27) and the tumour suppressor gene p53. Again these effects are only observed at high (> 10) µmol/L doses of phytoestrogens. Finally the effects of phytoestrogens on breast cancer may be mediated by their ability to inhibit local oestrogen synthesis and induce epigenetic changes. There are, though, difficulties in reconciling epidemiological and experimental data due to the fact experimental doses, both in vivo and in vitro, far exceed the circulating concentrations of “free” unbound phytoestrogens measured in women on a high phytoestrogen diet or those taking phytoestrogen supplements.

Atherosclerosis and tumor suppressor molecules (review)

Atherosclerosis, the major cause of heart attack and stroke, is a chronic inflammatory disease characterized by the formation of atherosclerotic plaque. Oxidized low-density lipoprotein through increased oxidative stress has been identified as one of the primary factors responsible for atherogenesis. Cell proliferation and death are key processes in the progression of atherosclerosis. The oxidative environment in areas of lipid accumulation is mainly created by the production of reactive oxygen species, which are assumed to mediate vascular tissue injury. Oxidative DNA damage and levels of DNA repair are reduced during dietary lipid lowering. The tumor suppressor molecules play a pivotal role in regulating cell proliferation, DNA repair and cell death, which are important processes in regulating the composition of atherosclerotic plaque. Accordingly, in this review, we discuss the fundamental role of tumor suppressor molecules in regulating atherogenesis. In particular, we discuss how tumor suppressor molecules are activated in the complex environment of atherosclerotic plaque, and regulate growth arrest, cell senescence and the apoptosis of vascular smooth muscle cells, which may protect against the progression of atherosclerosis. In addition, we discuss promising alternatives to the use of medications (such as statin) against atherosclerosis, namely diet, with the use of plant-derived supplements to modulate the expression and/or activity of tumor suppressor molecules. We also summarize the progress of research made on herbs with a focus on the modulatory roles of tumor suppressors, and on the molecular mechanisms underlying the prevention if atherosclerosis, supporting designs for further research in this field.

Nuclear receptors and epigenetic regulation: opportunities for nutritional targeting and disease prevention

Posttranslational modifications of histones, alterations in the recruitment and functions of non-histone proteins, DNA methylation, and changes in expression of noncoding RNAs contribute to current models of epigenetic regulation. Nuclear receptors (NRs) are a group of transcription factors that, through ligand-binding, act as sensors to changes in nutritional, environmental, developmental, pathophysiologic, and endocrine conditions and drive adaptive responses via gene regulation. One mechanism through which NRs direct gene expression is the assembly of transcription complexes with cofactors and coregulators that possess chromatin-modifying properties. Chromatin modifications can be transient or become part of the cellular "memory" and contribute to genomic imprinting. Because many food components bind to NRs, they can ultimately influence transcription of genes associated with biologic processes, such as inflammation, proliferation, apoptosis, and hormonal response, and alter the susceptibility to chronic diseases (e.g., cancer, diabetes, obesity). The objective of this review is to highlight how NRs influence epigenetic regulation and the relevance of dietary compound-NR interactions in human nutrition and for disease prevention and treatment. Identifying gene targets of unliganded and bound NRs may assist in the development of epigenetic maps for food components and dietary patterns. Progress in these areas may lead to the formulation of disease-prevention models based on epigenetic control by individual or associations of food ligands of NRs.

Endocrine disruption of the epigenome: a breast cancer link

The heritable component of breast cancer accounts for only a small proportion of total incidences. Environmental and lifestyle factors are therefore considered to among the major influencing components increasing breast cancer risk. Endocrine-disrupting chemicals (EDCs) are ubiquitous in the environment. The estrogenic property of EDCs has thus shown many associations between ongoing exposures and the development of endocrine-related diseases, including breast cancer. The environment consists of a heterogenous population of EDCs and despite many identified modes of action, including that of altering the epigenome, drawing definitive correlations regarding breast cancer has been a point of much discussion. In this review, we describe in detail well-characterized EDCs and their actions in the environment, their ability to disrupt mammary gland formation in animal and human experimental models and their associations with exposure and breast cancer risk. We also highlight the susceptibility of early-life exposure to each EDC to mediate epigenetic alterations, and where possible describe how these epigenome changes influence breast cancer risk.

Environmental epigenetics and its implication on disease risk and health outcomes

This review focuses on how environmental factors through epigenetics modify disease risk and health outcomes. Major epigenetic events, such as histone modifications, DNA methylation, and microRNA expression, are described. The function of dose, duration, composition, and window of exposure in remodeling the individual's epigenetic terrain and disease susceptibility are addressed. The ideas of lifelong editing of early-life epigenetic memories, transgenerational effects through germline transmission, and the potential role of hydroxylmethylation of cytosine in developmental reprogramming are discussed. Finally, the epigenetic effects of several major classes of environmental factors are reviewed in the context of pathogenesis of disease. These include endocrine disruptors, tobacco smoke, polycyclic aromatic hydrocarbons, infectious pathogens, particulate matter, diesel exhaust particles, dust mites, fungi, heavy metals, and other indoor and outdoor pollutants. We conclude that the summation of epigenetic modifications induced by multiple environmental exposures, accumulated over time, represented as broad or narrow, acute or chronic, developmental or lifelong, may provide a more precise assessment of risk and consequences. Future investigations may focus on their use as readouts or biomarkers of the totality of past exposure for the prediction of future disease risk and the prescription of effective countermeasures.

Interactions of isoflavones and other plant derived estrogens with estrogen receptors for prevention and treatment of breast cancer-considerations concerning related efficacy and safety

Phytoestrogens are natural endocrine disruptors that interfere with estrogenic pathways. They insert directly within the hormone-binding domain of ERα and β, with a preference for the β isoform of which the concentration predominates in the normal mammary epithelium. Since ERβ antagonizes the growth promoting effect of ERα, which is mainly expressed in estrogen-sensitive tumor cells, a potential protective action against breast cancer incidence has been ascribed to phytoestrogens. The fact that Asian women living in far-east countries who consume isoflavone-rich food are less subjected to breast cancer emergence than their congeners in the USA as well as Caucasian women has been advocated to justify such a concept. Overview of data concerning the mechanism of action phytoestrogens reveals that such a view is an oversimplification: Such compounds interfere with a huge panel of regulatory proteins, giving rise to both promoting and antagonizing carcinogenic effects. Moreover, various physiological and pathological factors able to amplify these effects are not often sufficiently taken into account, which increases the difficulty to interpret data. Nevertheless, this overview of data established that chemical structures and concentrations modulate such effects: at the micromolar level, isoflavones activate ERα-mediated transcription and breast cancer cell proliferation while flavones fail to induce any significant promoting effects. At higher doses, both classes of compounds may display an antitumor activity. Reasons for such distinct behaviors as well as their potential impact in therapeutic applications are analyzed here. Ability of isoflavones and flavones to antagonize the association of calmodulin to ERα, which is required for its enhanced transcriptional activity is evoked to justify the antitumor activity ascribed to some flavones. Finally, a suspicion that peculiar classes of phytoestrogens may adopt a SERM-like conformation is addressed in a context of selection and synthesis of compounds with non-equivocal therapeutic value. This article is part of a Special Issue entitled "Phytoestrogens".

Histone lysine trimethylation or acetylation can be modulated by phytoestrogen, estrogen or anti-HDAC in breast cancer cell lines

AIM

The isoflavones genistein, daidzein and equol (daidzein metabolite) have been reported to interact with epigenetic modifications, specifically hypermethylation of tumor suppressor genes. The objective of this study was to analyze and understand the mechanisms by which phytoestrogens act on chromatin in breast cancer cell lines.

MATERIALS & METHODS

Two breast cancer cell lines, MCF-7 and MDA-MB 231, were treated with genistein (18.5 µM), daidzein (78.5 µM), equol (12.8 µM), 17β-estradiol (10 nM) and suberoylanilide hydroxamic acid (1 µM) for 48 h. A control with untreated cells was performed. 17β-estradiol and an anti-HDAC were used to compare their actions with phytoestrogens. The chromatin immunoprecipitation coupled with quantitative PCR was used to follow soy phytoestrogen effects on H3 and H4 histones on H3K27me3, H3K9me3, H3K4me3, H4K8ac and H3K4ac marks, and we selected six genes (EZH2, BRCA1, ERα, ERβ, SRC3 and P300) for analysis.

RESULTS

Soy phytoestrogens induced a decrease in trimethylated marks and an increase in acetylating marks studied at six selected genes.

CONCLUSION

We demonstrated that soy phytoestrogens tend to modify transcription through the demethylation and acetylation of histones in breast cancer cell lines.

Diverse effects of phytoestrogens on the reproductive performance: cow as a model

Phytoestrogens, polyphenolic compounds derived from plants, are more and more common constituents of human and animal diets. In most of the cases, these chemicals are much less potent than endogenous estrogens but exert their biological effects via similar mechanisms of action. The most common source of phytoestrogen exposure to humans as well as ruminants is soybean-derived foods that are rich in the isoflavones genistein and daidzein being metabolized in the digestive tract to even more potent metabolites-para-ethyl-phenol and equol. Phytoestrogens have recently come into considerable interest due to the increasing information on their adverse effects in human and animal reproduction, increasing the number of people substituting animal proteins with plant-derived proteins. Finally, the soybean becomes the main source of protein in animal fodder because of an absolute prohibition of bone meal use for animal feeding in 1995 in Europe. The review describes how exposure of soybean-derived phytoestrogens can have adverse effects on reproductive performance in female adults.

Flavonoids and cancer prevention: a review of the evidence

The objective of this work is to review data from epidemiological and preclinical studies addressing the potential benefits of diets based on flavonoids for cancer prevention. Flavonoids are subdivided into subclasses including flavonols, flavones, flavanones, flavan-3-ols, anthocyanidins, and isoflavones. Epidemiological studies suggest dietary intake of flavonoids may reduce the risk of tumors of the breast, colon, lung, prostate, and pancreas. However, some studies have reported inconclusive or even harmful associations. A major challenge in the interpretation of epidemiological studies is that most of the data originate from case-control studies and retrospective acquisition of flavonoid intake. Differences in agricultural, sociodemographics, and lifestyle factors contribute to the heterogeneity in the intake of flavonoids among populations residing in the United States, Europe, and Asia. Dose and timing of exposure may influence the anticancer response to flavonoid-rich diets. A limited number of intervention trials of flavonoids have documented cancer preventative effects. Proposed anticancer mechanisms for flavonoids are inhibition of proliferation, inflammation, invasion, metastasis, and activation of apoptosis. Prospective studies with larger sample sizes are needed to develop biomarkers of flavonoid intake and effect. Mechanistic studies are needed to ascertain how flavonoid-rich diets influence gene regulation for cancer prevention.

Soy products in the management of breast cancer

PURPOSE OF REVIEW

Meta-analyses of epidemiological studies of soy consumption and breast cancer risk have demonstrated modest protective effects, usually attributed to isoflavones. Concern has been expressed, however, that the estrogenic activity of isoflavones may have adverse effects on breast cancer recurrence.

RECENT FINDINGS

The review covers epidemiological studies that have investigated the impact of soy consumption in breast cancer patients on recurrence and mortality. There are preliminary data to suggest that soy has differential effects on recurrence in human epidermal growth factor receptor-2 positive and human epidermal growth factor receptor-2 negative tumours. Recent studies on mechanisms of action of soy in breast cancer provide insights into epigenetic effects and the interaction of isoflavones with IGF-1 and with a number of polymorphisms of genes associated with breast cancer risk such as MDM2 and CYP1B1.

SUMMARY

Overall, these studies indicate that soy foods consumed at levels comparable to those in Asian populations have no detrimental effects on risk of breast cancer recurrence and in some cases significantly reduce the risk. Importantly, soy does not appear to interfere with tamoxifen or anastrozole therapy. Recent research suggests that women who are at increased risk of breast cancer due to polymorphisms in genes associated with the disease may especially benefit from high soy isoflavone intake.