Mechanisms of action of isothiocyanates in cancer chemoprevention: an update

Chemopreventive aspects, investigational anticancer applications and current perspectives on allyl isothiocyanate (AITC): a review

Allyl isothiocyanates (AITC) have gained recognition in recent years as effective chemotherapeutic and epigenetic modulators. The chemopreventive properties and toxicological perspectives of AITCs from the last few decades were taken into account by a number of investigations. Their active therapeutic relevance was hindered by a number of factors, including instability under typical physiological conditions and low bioavailability due to low aqueous solubility. In this review, we highlighted the chemopreventive attributes of AITC in relation to its molecular mechanisms and metabolic fate for cancer. Moreover, we emphasized on investigational anticancer activities and various strategies for delivery of AITC in different types of cancer. Considering cellular interactions, we shed light on the toxicological properties of AITCs to address further issues regarding their assessment in therapeutic development. This review identifies knowledge gaps with various contemporary approaches involving most recent studies and may pave the way for a better understanding for the development of novel AITC therapeutics.

The Key Role of GSH in Keeping the Redox Balance in Mammalian Cells: Mechanisms and Significance of GSH in Detoxification via Formation of Conjugates

Glutathione (GSH) is a ubiquitous tripeptide that is biosynthesized in situ at high concentrations (1-5 mM) and involved in the regulation of cellular homeostasis via multiple mechanisms. The main known action of GSH is its antioxidant capacity, which aids in maintaining the redox cycle of cells. To this end, GSH peroxidases contribute to the scavenging of various forms of ROS and RNS. A generally underestimated mechanism of action of GSH is its direct nucleophilic interaction with electrophilic compounds yielding thioether GSH S-conjugates. Many compounds, including xenobiotics (such as NAPQI, simvastatin, cisplatin, and barbital) and intrinsic compounds (such as menadione, leukotrienes, prostaglandins, and dopamine), form covalent adducts with GSH leading mainly to their detoxification. In the present article, we wish to present the key role and significance of GSH in cellular redox biology. This includes an update on the formation of GSH-S conjugates or GSH adducts with emphasis given to the mechanism of reaction, the dependence on GST (GSH S-transferase), where this conjugation occurs in tissues, and its significance. The uncovering of the GSH adducts' formation enhances our knowledge of the human metabolome. GSH-hematin adducts were recently shown to have been formed spontaneously in multiples isomers at hemolysates, leading to structural destabilization of the endogenous toxin, hematin (free heme), which is derived from the released hemoglobin. Moreover, hemin (the form of oxidized heme) has been found to act through the Kelch-like ECH associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor-2 (Nrf2) signaling pathway as an epigenetic modulator of GSH metabolism. Last but not least, the implications of the genetic defects in GSH metabolism, recorded in hemolytic syndromes, cancer and other pathologies, are presented and discussed under the framework of conceptualizing that GSH S-conjugates could be regarded as signatures of the cellular metabolism in the diseased state.

Reviewing the Prospective Pharmacological Potential of Isothiocyanates in Fight against Female-Specific Cancers

Gynecological cancers are the most commonly diagnosed malignancies in females worldwide. Despite the advancement of diagnostic tools as well as the availability of various therapeutic interventions, the incidence and mortality of female-specific cancers is still a life-threatening issue, prevailing as one of the major health problems worldwide. Lately, alternative medicines have garnered immense attention as a therapeutic intervention against various types of cancers, seemingly because of their safety profiles and enhanced effectiveness. Isothiocyanates (ITCs), specifically sulforaphane, benzyl isothiocyanate, and phenethyl isothiocyanate, have shown an intriguing potential to actively contribute to cancer cell growth inhibition, apoptosis induction, epigenetic alterations, and modulation of autophagy and cancer stem cells in female-specific cancers. Additionally, it has been shown that ITCs plausibly enhance the chemo-sensitization of many chemotherapeutic drugs. To this end, evidence has shown enhanced efficacy in combinatorial regimens with conventional chemotherapeutic drugs and/or other phytochemicals. Reckoning with these, herein, we discuss the advances in the knowledge regarding the aspects highlighting the molecular intricacies of ITCs in female-specific cancers. In addition, we have also argued regarding the potential of ITCs either as solitary treatment or in a combinatorial therapeutic regimen for the prevention and/or treatment of female-specific cancers. Hopefully, this review will open new horizons for consideration of ITCs in therapeutic interventions that would undoubtedly improve the prognosis of the female-specific cancer clientele. Considering all these, it is reasonable to state that a better understanding of these molecular intricacies will plausibly provide a facile opportunity for treating these female-specific cancers.

In Vitro Anti-Leishmanial Activity of Glucosinolate Fraction from Alyssum linifolium Steph. ex Willd (Brassicaceae)

Objectives

The intracellular parasitic protozoan, Leishmania spp., causes several forms of diseases in humans. Cytotoxicity and emergence of new strains resistance to the current anti-leishmanial drugs have encouraged researchers to focus on new resources. Glucosinolates (GSL) are found mainly in the Brassicaceae family with potential cytotoxic and anti-parasitic properties. The present study reports in vitro antileishmanial activity of the GSL fraction from Alyssum linifolium seeds against Leishmania major.

Materials and Methods

The GSL fraction was prepared by ion-exchange and reversed-phase chromatography. For the assessment of antileishmanial activity, the promastigotes and amastigotes of L. major were treated with different concentrations of the fraction (75-625 μg/mL).

Results

The IC₅₀ was 245 µg/mL for anti-promastigote effect of the GSL fraction and 250 µg/mL for its anti-amastigote effect that had a significant difference (p<0.05) with both glucantime and amphotericin B. The selectivity index of the GSL fraction (15.8), to glucantime and amphotericin B, was greater than 10, indicating the selective effect of this fraction against L. major amastigotes. Glucoiberverin was the major constituent of the GSL fraction characterized using nuclear magnetic resonance and electron ionization-mass spectrometry spectra. Based on gas chromatography-mass spectrometry data, iberverin and iberverin nitrile, the hydrolysis constituents from glucoiberverin, included 76.91% of the total seed volatiles.

Conclusion

The results suggest that GSLs like glucoiberverin could be considered a new promising candidate for further studies on antileishmanial activity.

Epigenetic regulation by metabolites from the gut microbiome

The gut microbiome can metabolise food components, such as dietary fibres and various phytochemicals; and the microbiome can also synthesise some nutrients, for example B vitamins. The metabolites produced by bacteria and other micro-organisms in the colon can have implications for health and disease risk. Some of these metabolites are epigenetically active, and can contribute to changes in the chemical modification and structure of chromatin by affecting the activity and expression of epigenetically-active enzymes, for example histone deacetylases and DNA methyltransferases. The epigenetic activity of such gut microbiome metabolites is reviewed herein.

Emergence of nutrigenomics and dietary components as a complementary therapy in cancer prevention

Cancer is an illness characterized by abnormal cell development and the capability to infiltrate or spread to rest of the body. A tumor is the term for this abnormal growth that develops in solid tissues like an organ, muscle, or bone and can spread to other parts of the body through the blood and lymphatic systems. Nutrition is a critical and immortal environmental component in the development of all living organisms encoding the relationship between a person's nutrition and their genes. Nutrients have the ability to modify gene expression and persuade alterations in DNA and protein molecules which is researched scientifically in nutrigenomics. These interactions have a significant impact on the pharmacokinetic properties of bioactive dietary components as well as their site of action/molecular targets. Nutrigenomics encompasses nutrigenetics, epigenetics, and transcriptomics as well as other "omic" disciplines like proteomics and metabolomics to explain the vast disparities in cancer risk among people with roughly similar life style. Clinical trials and researches have evidenced that alternation of dietary habits is potentially one of the key approaches for reducing cancer risk in an individual. In this article, we will target how nutrigenomics and functional food work as preventive therapy in reducing the risk of cancer.

Anticancer Activity, Mechanism, and Delivery of Allyl Isothiocyanate

Allyl isothiocyanate (AITC) is a phytochemical that is abundantly present in cruciferous vegetables of the Brassicaceae family, such as cabbage, broccoli, mustard, wasabi, and cauliflower. The pungent taste of these vegetables is mainly due to the content of AITC present in these vegetables. AITC is stored stably in the plant as its precursor sinigrin (a type of glucosinolate), which is physically separated from myrosin cells containing myrosinase. Upon tissue disruption, myrosinase gets released and hydrolyzes the sinigrin to produce AITC and by-products. AITC is an organosulfur compound, both an irritant and toxic, but it carries pharmacological properties, including anticancer, antibacterial, antifungal, and anti-inflammatory activities. Despite the promising anticancer effectiveness of AITC, its clinical application still possesses challenges due to several factors, i.e., low aqueous solubility, instability, and low bioavailability. In this review, the anticancer activity of AITC against several cancer models is summarized from the literature. Although the mechanism of action is still not fully understood, several pathways have been identified; these are discussed in this review. Not much attention has been given to the delivery of AITC, which hinders its clinical application. However, the few studies that have demonstrated the use of nanotechnology to facilitate the delivery of AITC are addressed.

Sulforaphane and Its Bifunctional Analogs: Synthesis and Biological Activity

For decades, various plants have been studied as sources of biologically active compounds. Compounds with anticancer and antimicrobial properties are the most frequently desired. Cruciferous plants, including Brussels sprouts, broccoli, and wasabi, have a special role in the research studies. Studies have shown that consumption of these plants reduce the risk of lung, breast, and prostate cancers. The high chemopreventive and anticancer potential of cruciferous plants results from the presence of a large amount of glucosinolates, which, under the influence of myrosinase, undergo an enzymatic transformation to biologically active isothiocyanates (ITCs). Natural isothiocyanates, such as benzyl isothiocyanate, phenethyl isothiocyanate, or the best-tested sulforaphane, possess anticancer activity at all stages of the carcinogenesis process, show antibacterial activity, and are used in organic synthesis. Methods of synthesis of sulforaphane, as well as its natural or synthetic bifunctional analogues with sulfinyl, sulfanyl, sulfonyl, phosphonate, phosphinate, phosphine oxide, carbonyl, ester, carboxamide, ether, or additional isothiocyanate functional groups, and with the unbranched alkyl chain containing 2-6 carbon atoms, are discussed in this review. The biological activity of these compounds are also reported. In the first section, glucosinolates, isothiocyanates, and mercapturic acids (their metabolites) are briefly characterized. Additionally, the most studied anticancer and antibacterial mechanisms of ITC actions are discussed.

The Role of Glucosinolates from Cruciferous Vegetables (Brassicaceae) in Gastrointestinal Cancers: From Prevention to Therapeutics

The gastrointestinal (GI) tract is composed of rapidly renewing cells, which increase the likelihood of cancer. Colorectal cancer is one of the most frequently diagnosed GI cancers and currently stands in second place regarding cancer-related mortality. Unfortunately, the treatment of GI is limited, and few developments have occurred in the field over the years. With this in mind, new therapeutic strategies involving biologically active phytocompounds are being evaluated as anti-cancer agents. Vegetables such as broccoli, brussels sprouts, cabbage, cauliflower, and radish, all belonging to the Brassicaceae family, are high in dietary fibre, minerals, vitamins, carotenoids, polyphenols, and glucosinolates. The latter compound is a secondary metabolite characteristic of this family and, when biologically active, has demonstrated anti-cancer properties. This article reviews the literature regarding the potential of Cruciferous vegetables in the prevention and/or treatment of GI cancers and the relevance of appropriate compound formulations for improving the stability and bioaccessibility of the major Cruciferous compounds, with a particular focus on glucosinolates.

Manipulation of Continuous and End-of-Day Red/Far-Red Light Ratios Affects Glucobrassicin and Gluconasturtiin Accumulation in Cabbage (Brassica oleracea) and Watercress (Nasturtium officinale), Respectively

Cabbage (Brassica oleracea) and watercress (Nasturtium officinale) produce glucobrassicin (GBS) and gluconasturtiin (GNST), precursors of chemopreventive compounds. Their accumulation is affected by environmental signals. We studied the impact of the red to far-red light (R/FR) ratio on GBS concentration in red ″Ruby Ball″ and green ″Tiara″ cabbage. Foliar shading, via weed surrogates that competed with cabbage plants for specific durations, induced R/FR variation among treatments. ″Ruby Ball″ GBS concentrations were the highest when R/FR within the canopy was the lowest. ″Tiara″ was unaffected by competition. The same trend was observed in a controlled environment using R and FR LEDs without weeds present. ″Ruby Ball″ subjected to an R/FR = 0.3 treatment had 2.5- and 1.4-fold greater GBS concentration compared to R/FR = 1.1 and 5.0 treatments combined. Watercress given end-of-day (EOD) R and/or FR pulses after the main photoperiod had the lowest GNST concentrations after an EOD FR pulse but the highest concentrations after an R followed by FR pulse.

Improved Production of Recombinant Myrosinase in Pichia pastoris

The effect of the deletion of a 57 bp native signal sequence, which transports the nascent protein through the endoplasmic reticulum membrane in plants, on improved AtTGG1 plant myrosinase production in Pichia pastoris was studied. Myrosinase was extracellularly produced in a 3-liter laboratory fermenter using α-mating factor as the secretion signal. After the deletion of the native signal sequence, both the specific productivity (164.8 U/L/h) and volumetric activity (27 U/mL) increased more than 40-fold compared to the expression of myrosinase containing its native signal sequence in combination with α-mating factor. The deletion of the native signal sequence resulted in slight changes in myrosinase properties: the optimum pH shifted from 6.5 to 7.0 and the maximal activating concentration of ascorbic acid increased from 1 mM to 1.5 mM. Kinetic parameters toward sinigrin were determined: 0.249 mM (K_m) and 435.7 U/mg (V_max). These results could be applied to the expression of other plant enzymes.

Sulforaphane: A Broccoli Bioactive Phytocompound with Cancer Preventive Potential

Simple Summary

As of the past decade, phytochemicals have become a major target of interest in cancer chemopreventive and chemotherapeutic research. Sulforaphane (SFN) is a metabolite of the phytochemical glucoraphanin, which is found in high abundance in cruciferous vegetables, such as broccoli, watercress, Brussels sprouts, and cabbage. In both distant and recent research, SFN has been shown to have a multitude of anticancer effects, increasing the need for a comprehensive review of the literature. In this review, we critically evaluate SFN as an anticancer agent and its mechanisms of action based on an impressive number of in vitro, in vivo, and clinical studies.

Abstract

There is substantial and promising evidence on the health benefits of consuming broccoli and other cruciferous vegetables. The most important compound in broccoli, glucoraphanin, is metabolized to SFN by the thioglucosidase enzyme myrosinase. SFN is the major mediator of the health benefits that have been recognized for broccoli consumption. SFN represents a phytochemical of high interest as it may be useful in preventing the occurrence and/or mitigating the progression of cancer. Although several prior publications provide an excellent overview of the effect of SFN in cancer, these reports represent narrative reviews that focused mainly on SFN’s source, biosynthesis, and mechanisms of action in modulating specific pathways involved in cancer without a comprehensive review of SFN’s role or value for prevention of various human malignancies. This review evaluates the most recent state of knowledge concerning SFN’s efficacy in preventing or reversing a variety of neoplasms. In this work, we have analyzed published reports based on in vitro, in vivo, and clinical studies to determine SFN’s potential as a chemopreventive agent. Furthermore, we have discussed the current limitations and challenges associated with SFN research and suggested future research directions before broccoli-derived products, especially SFN, can be used for human cancer prevention and intervention.

Metabolic and biotransformation effects on dietary glucosinolates, their bioavailability, catabolism and biological effects in different organisms

Glucosinolate-producing plants have long been recognized for both their distinctive benefits to human nutrition and their resistance traits against pathogens and herbivores. Despite the accumulation of glucosinolates (GLS) in plants is associated with their resistance to various biotic and abiotic stresses, the defensive and biological activities of GLS are commonly conveyed by their metabolic products. In view of this, metabolism is considered the driving factor upon the interactions of GLS-producing plants with other organisms, also influenced by plant and plant attacking or digesting organism characteristics. Several microbial pathogens and insects have evolved the capacity to detoxify GLS-hydrolysis products or inhibit their formation via different means, highlighting the relevance of their metabolic abilities for the plants' defense system activation and target organism detoxification. Strikingly, some bacteria, fungi and insects can likewise produce their own myrosinase (MYR)-like enzymes in one of the most important adaptation strategies against the GLS-MYR plant defense system. Knowledge of GLS metabolic pathways in herbivores and pathogens can impact plant protection efforts and may be harnessed upon for genetically modified plants that are more resistant to predators. In humans, the interest in the implementation of GLS in diets for the prevention of chronic diseases has grown substantially. However, the efficiency of such approaches is dependent on GLS bioavailability and metabolism, which largely involves the human gut microbiome. Among GLS-hydrolytic products, isothiocyanates (ITC) have shown exceptional properties as chemical plant defense agents against herbivores and pathogens, along with their health-promoting benefits in humans, at least if consumed in reasonable amounts. Deciphering GLS metabolic pathways provides critical information for catalyzing all types of GLS towards the generation of ITCs as the biologically most active metabolites. This review provides an overview on contrasting metabolic pathways in plants, bacteria, fungi, insects and humans towards GLS activation or detoxification. Further, suggestions for the preparation of GLS containing plants with improved health benefits are presented.

Changes in Lifestyle and Dietary Habits during COVID-19 Lockdown in Italy: Results of an Online Survey

COVID-19 is an unprecedented global pandemic. On 12 March 2020, a lockdown order was issued in Italy in attempt to contain the health crisis. The study aimed to assess the impact of the COVID-19 lockdown on diet, physical activity, sleep quality, and distress in an Italian cohort. An online anonymous interview, which included validated questionnaires was created to compare lifestyle habits pre- and during the lockdown. Data analysis from 604 subjects with a mean age of 29.8 years was carried out using multivariate analysis. Compared to pre-COVID-19 times, 67% of people changed their eating habits and increased consumption of foods containing added sugars. Women and men with low adherence to the Mediterranean Diet (MedDiet) were more likely to be physically inactive (p < 0.0001 and p < 0.01, respectively). Results from logistic regression showed a three times higher risk of being inactive if adherence to the MedDiet was low (p < 0.0001), especially in men between 26 and 35 years. Lower levels of distress were reported in males who were physically active (89%) (p < 0.001). Our findings may help to identify effective lifestyle interventions during restrictive conditions.

Optimisation of Recombinant Myrosinase Production in Pichia pastoris

Myrosinase is a plant defence enzyme catalysing the hydrolysis of glucosinolates, a group of plant secondary metabolites, to a range of volatile compounds. One of the products, isothiocyanates, proved to have neuroprotective and chemo-preventive properties, making myrosinase a pharmaceutically interesting enzyme. In this work, extracellular expression of TGG1 myrosinase from Arabidopsis thaliana in the Pichia pastoris KM71H (Mut^S) strain was upscaled to a 3 L laboratory fermenter for the first time. Fermentation conditions (temperature and pH) were optimised, which resulted in a threefold increase in myrosinase productivity compared to unoptimised fermentation conditions. Dry cell weight increased 1.5-fold, reaching 100.5 g/L without additional glycerol feeding. Overall, a specific productivity of 4.1 U/L_medium/h was achieved, which was 102.5-fold higher compared to flask cultivations.

Dietary isothiocyanates inhibit cancer progression by modulation of epigenome

Cell cycle, growth, survival and metabolism are tightly regulated together and failure in cellular regulation leads to carcinogenesis. Several signaling pathways like the PI3K, WNT, MAPK and NFKb pathway exhibit aberrations in cancer and help achieve hallmark capabilities. Clinical research and in vitro studies have highlighted the role of epigenetic alterations in cancer onset and development. Altered gene expression patterns enabled by changes in DNA methylation, histone modifications and RNA processing have proven roles in cancer hallmark acquisition. The reversible nature of epigenetic processes offers robust therapeutic targets. Dietary bioactive compounds offer a vast compendium of effective therapeutic moieties. Isothiocyanates (ITCs) sourced from cruciferous vegetables demonstrate anti-proliferative, pro-apoptotic, anti-inflammatory, anti-migratory and anti-angiogenic effect against several cancers. ITCs also modulate the redox environment, modulate signaling pathways including PI3K, MAPK, WNT, and NFkB. They also modulate the epigenetic machinery by regulating the expression and activity of DNA methyltransferases, histone modifiers and miRNA. This further enhances their transcriptional modulation of key cellular regulators. In this review, we comprehensively assess the impact of ITCs such as sulforaphane, phenethyl isothiocyanate, benzyl isothiocyanate and allyl isothiocyanate on cancer and document their effect on various molecular targets. Overall, this will facilitate consolidation of the current understanding of the anti-cancer and epigenetic modulatory potential of these compounds and recognize the gaps in literature. Further, we discuss avenues of future research to develop these compounds as potential therapeutic entities.

Effects of cooking methods on total isothiocyanate yield from cruciferous vegetables

Cruciferous vegetables are primary sources of dietary isothiocyanates (ITCs), a group of phytochemicals showing promising cancer-chemopreventive activities in multiple cancer models. However, no study has thoroughly examined how cooking affects the yields of ITCs from cruciferous vegetables. In this study, a high-performance liquid chromatography (HPLC)-based cyclocondensation assay was performed to examine the ITC yields from four major cruciferous vegetables (broccoli, cabbage, cauliflower, and kale) under six cooking conditions (stir-frying, steaming, microwaving, boiling, stewing, and chip-baking for kale only) and measured the level of ITCs under the raw condition for a comprehensive list of cruciferous vegetables and ITC-containing condiments. A wide range of ITC yields was found across vegetables and condiments. Cooking significantly altered the ITC yields, showing an averagely four-fold increase by lightly cooking (stir-frying, steaming, and microwaving) and a 58% decrease by heavily cooking (boiling, stewing, and chip-baking). These findings will provide the evidence-based cooking guidance on cruciferous vegetable consumption and help better estimate dietary ITC exposure in epidemiologic studies.

Breast and Gut Microbiota Action Mechanisms in Breast Cancer Pathogenesis and Treatment

In breast cancer (BC) the employment of sequencing technologies for metagenomic analyses has allowed not only the description of the overall metagenomic landscape but also the specific microbial changes and their functional implications. Most of the available data suggest that BC is related to bacterial dysbiosis in both the gut microenvironment and breast tissue. It is hypothesized that changes in the composition and functions of several breast and gut bacterial taxa may contribute to BC development and progression through several pathways. One of the most prominent roles of gut microbiota is the regulation of steroid-hormone metabolism, such as estrogens, a component playing an important role as risk factor in BC development, especially in postmenopausal women. On the other hand, breast and gut resident microbiota are the link in the reciprocal interactions between cancer cells and their local environment, since microbiota are capable of modulating mucosal and systemic immune responses. Several in vivo and in vitro studies show remarkable evidence that diet, probiotics and prebiotics could exert important anticarcinogenic effects in BC. Moreover, gut microbiota have an important role in the metabolism of chemotherapeutic drugs and in the activity of immunogenic chemotherapies since they are a potential dominant mediator in the response to cancer therapy. Then, the microbiome impact in BC is multi-factorial, and the gut and breast tissue bacteria population could be important in regulating the local immune system, in tumor formation and progression and in therapy response and/or resistance.

Organic Isothiocyanates as Hydrogen Sulfide Donors

Significance: Hydrogen sulfide (H₂S), the "new entry" in the series of endogenous gasotransmitters, plays a fundamental role in regulating the biological functions of various organs and systems. Consequently, the lack of adequate levels of H₂S may represent the etiopathogenetic factor of multiple pathological alterations. In these diseases, the use of H₂S donors represents a precious and innovative opportunity. Recent Advances: Natural isothiocyanates (ITCs), sulfur compounds typical of some botanical species, have long been investigated because of their intriguing pharmacological profile. Recently, the ITC moiety has been proposed as a new H₂S-donor chemotype (with a l-cysteine-mediated reaction). Based on this recent discovery, we can clearly observe that almost all the effects of natural ITCs can be explained by the H₂S release. Consistently, the ITC function was also used as an original H₂S-releasing moiety for the design of synthetic H₂S donors and original "pharmacological hybrids." Very recently, the chemical mechanism of H₂S release, resulting from the reaction between l-cysteine and some ITCs, has been elucidated. Critical Issues: Available literature gives convincing demonstration that H₂S is the real player in ITC pharmacology. Further, countless studies have been carried out on natural ITCs, but this versatile moiety has been used only rarely for the design of synthetic H₂S donors with optimal drug-like properties. Future Directions: The development of more ITC-based synthetic H₂S donors with optimal drug-like properties and selectivity toward specific tissues/pathologies seem to represent a stimulating and indispensable prospect of future experimental activities.

The Microbiome-Estrogen Connection and Breast Cancer Risk

The microbiome is undoubtedly the second genome of the human body and has diverse roles in health and disease. However, translational progress is limited due to the vastness of the microbiome, which accounts for over 3.3 million genes, whose functions are still unclear. Numerous studies in the past decade have demonstrated how microbiome impacts various organ-specific cancers by altering the energy balance of the body, increasing adiposity, synthesizing genotoxins and small signaling molecules, and priming and regulating immune response and metabolism of indigestible dietary components, xenobiotics, and pharmaceuticals. In relation to breast cancer, one of the most prominent roles of the human microbiome is the regulation of steroid hormone metabolism since endogenous estrogens are the most important risk factor in breast cancer development especially in postmenopausal women. Intestinal microbes encode enzymes capable of deconjugating conjugated estrogen metabolites marked for excretion, pushing them back into the enterohepatic circulation in a biologically active form. In addition, the intestinal microbes also break down otherwise indigestible dietary polyphenols to synthesize estrogen-like compounds or estrogen mimics that exhibit varied estrogenic potency. The present account discusses the potential role of gastrointestinal microbiome in breast cancer development by mediating metabolism of steroid hormones and synthesis of biologically active estrogen mimics.

The Role of Isothiocyanates as Cancer Chemo-Preventive, Chemo-Therapeutic and Anti-Melanoma Agents

Many studies have shown evidence in support of the beneficial effects of phytochemicals in preventing chronic diseases, including cancer. Among such phytochemicals, sulphur-containing compounds (e.g., isothiocyanates (ITCs)) have raised scientific interest by exerting unique chemo-preventive properties against cancer pathogenesis. ITCs are the major biologically active compounds capable of mediating the anticancer effect of cruciferous vegetables. Recently, many studies have shown that a higher intake of cruciferous vegetables is associated with reduced risk of developing various forms of cancers primarily due to a plurality of effects, including (i) metabolic activation and detoxification, (ii) inflammation, (iii) angiogenesis, (iv) metastasis and (v) regulation of the epigenetic machinery. In the context of human malignant melanoma, a number of studies suggest that ITCs can cause cell cycle growth arrest and also induce apoptosis in human malignant melanoma cells. On such basis, ITCs could serve as promising chemo-therapeutic agents that could be used in the clinical setting to potentiate the efficacy of existing therapies.

Bis (Isothiocyanatomethyl) Benzene, A Plant Derived Anti-Neoplastic Compound: Purified from Moringa Oleifera Leaf Extract

BACKGROUND

Moringa oleifera lam, commonly known as "Sajina", is an indigenous species to India. In our folk medicine, it is used for the treatment of Canker (cancer). The Moringa oleifera leaf extract contains many phyto-compounds, with some being anti-neoplastic in nature.

OBJECTIVE

Our preliminary study showed that the leaf extract significantly kills cancer cells compared to normal cells. On searching for the new phyto-compound, Bis-isothiocyanatomethyl) benzene was purified and isolated.

METHODS

The sequential process of fractional distillation, column chromatography, followed by TLC and HPLC is performed for purification. Every fraction from each step was tested on HeLa cell line for evaluating the presence of the phyto-compound.

RESULTS AND CONCLUSION

FTIR peak analysis of a single phyto-compound shows the presence of thiocyanate group, aromatic carbon group. 1H & 13C NMR peak analysis along with High-resolution mass spectroscopy (HRMS) calculation confirm the chemical structure with IUPAC name [Bis (Isothiocyanatomethyl) benzene]. Previously, Isothiocyanatomethyl- benzene solely or in conjugation with sugar molecule has been reported, but its dimeric form in nature hasnot yet been published anywhere. It shows anticancer activity by retarding cancer cell growth & inhibits carcinogenesis on HeLa, MCF-7, and MDA-MB-231 cell lines by caspase 3 apoptotic pathway and showed comparatively less cytotoxicity to PBMC cell. It shows anticancer activity almost the same as the market available drug Cis-Platin. Therefore, further extrapolating its activity with different concentrations may result in its use as a drug formulation for the treatment of cancer.

Antiproliferative, Proapoptotic, Antioxidant and Antimicrobial Effects of Sinapis nigra L. and Sinapis alba L. Extracts

High Brassicaceae consumption reduces the risk of developing several cancer types, probably due to high levels of glucosinolates. Extracts from Sinapis nigra L. (S. nigra) and Sinapis alba L. (S. alba) have been obtained from leaves and seeds under different conditions using ethanol/water mixtures because their glucosinolates are well accepted by the food industry. The EtOH/H₂O 8:2 mixture gives better yields in glucosinolate amounts from ground seeds, mainly, sinalbin in S. alba and sinigrin in S. nigra. The highest antiproliferative activity in both non-tumor and tumor cell lines was induced by S. alba seeds extract. To evaluate whether the effect of Sinapis species (spp) was only due to glucosinolate content or whether it was influenced by the extracts’ complexity, cells were treated with extracts or glucosinolates, in the presence of myrosinase. Pure sinigrin did not modify cell proliferation, while pure sinalbin was less effective than the extract. The addition of myrosinase increased the antiproliferative effects of the S. nigra extract and sinigrin. Antiproliferative activity was correlated to Mitogen-Activated Protein Kinases modulation, which was cell and extract-dependent. Cell-cycle analysis evidenced a proapoptotic effect of S. alba on both tumor cell lines and of S. nigra only on HCT 116. Both extracts showed good antimicrobial activity in disc diffusion tests and on ready-to-eat fresh salad. These results underline the potential effects of Sinapis spp in chemoprevention and food preservation.

The Effect of Sulforaphane on Glyoxalase I Expression and Activity in Peripheral Blood Mononuclear Cells

Studies demonstrate that the potential health-beneficial effect of sulforaphane (SR), a compound formed in broccoli, is the result of a number of mechanisms including upregulation of phase two detoxification enzymes. Recent studies suggest that SR increases expression/activity of glyoxalase 1 (Glo1), an enzyme involved in the degradation of methylglyoxal, is major precursor of advanced glycation end products. Those compounds are associated with diabetes complications and other age-related diseases. In this study, the effect of SR on the expression/activity of Glo1 in peripheral blood mononuclear cells (PBMCs) from 8 healthy volunteers was investigated. PBMCs were isolated and incubated with SR (2.5 μM-concentration achievable by consuming a broccoli portion) for 24 h and 48 h. Glo1 activity/expression, reduced glutathione (GSH), and glutathione-S-transferase gene expression were measured. Glo1 activity was not affected while after 48 h a slight but significant increase of its gene expression (1.03-fold) was observed. GSTP1 expression slightly increased after 24 h incubation (1.08-fold) while the expressions of isoform GSTT2 and GSTM2 were below the limit of detection. GSH sharply decreased, suggesting the formation of GSH-SR adducts that may have an impact SR availability. Those results suggest that a regular exposure to SR by broccoli consumption or SR supplements may enhance Glo1.

Nontoxic Glucomoringin-Isothiocyanate (GMG-ITC) Rich Soluble Extract Induces Apoptosis and Inhibits Proliferation of Human Prostate Adenocarcinoma Cells (PC-3)

The incidence of prostate cancer malignancy along with other cancer types is increasing worldwide, resulting in high mortality rate due to lack of effective medications. Moringa oleifera has been used for the treatment of communicable and non-communicable ailments across tropical countries, yet, little has been documented regarding its effect on prostate cancer. We evaluated the acute toxicity and apoptosis inducing effect of glucomoringin-isothiocyanate rich soluble extracts (GMG-ITC-RSE) from M. oleifera in vivo and in vitro, respectively. Glucomoringin was isolated, identified, and characterized using fundamental analytical chemistry tools where Sprague-Dawley (SD) rats, murine fibroblast (3T3), and human prostate adenocarcinoma cells (PC-3) were used for acute toxicity and bioassays experiments. GMG-ITC-RSE did not instigate adverse toxic reactions to the animals even at high doses (2000 mg/kg body weight) and affected none of the vital organs in the rats. The extract exhibited high levels of safety in 3T3 cells, where more than 90% of the cells appeared viable when treated with the extract in a time-dependent manner even at high dose (250 µg/mL). GMG-ITC-RSE significantly triggered morphological aberrations distinctive to apoptosis observed under microscope. These findings obviously revealed the putative safety of GMG-ITC-RSE in vivo and in vitro, in addition to its anti-proliferative effect on PC-3 cells.

Food as Pharma? The Case of Glucosinolates

BACKGROUND

Glucosinolates (GLSs) are dietary plant secondary metabolites occurring in the order Brassicales with potential health effects, in particular as anti-carcinogenic compounds. GLSs are converted into a variety of breakdown products (BPs) upon plant tissue damage and by the gut microbiota. GLS biological activity is related to BPs rather than to GLSs themselves.

METHODS

we have reviewed the most recent scientific literature on the metabolic fate and the biological effect of GLSs with particular emphasis on the epidemiological evidence for health effect and evidence from clinical trials. An overview of potential molecular mechanisms underlying GLS biological effect is provided. The potential toxic or anti-nutritional effect has also been discussed.

RESULTS

Epidemiological and human in vivo evidence point towards a potential anti-cancer effect for sulforaphane, indole-3-carbinol and 3,3-diindolylmethane. A number of new human clinical trials are on-going and will likely shed further light on GLS protective effect towards cancer as well as other diseases. BPs biological effect is the results of a plurality of molecular mechanisms acting simultaneously which include modulation of xenobiotic metabolism, modulation of inflammation, regulation of apoptosis, cell cycle arrest, angiogenesis and metastasis and regulation of epigenetic events. BPs have been extensively investigated for their protective effect towards cancer but in recent years the interest also includes other diseases.

CONCLUSION

It appears that certain BPs may protect against and may even represent a therapeutic strategy against several forms of cancer. Whether this latter effect can be achieved through diet or supplements should be investigated more thoroughly.

Extraction, profiling and bioactivity analysis of volatile glucosinolates present in oil extract of Brassica juncea var. raya

Cruciferous vegetables are rich source of glucosinolates (GSLs), which in presence of myrosinase enzyme cause hydrolytic cleavage and result in different hydrolytic products like isothiocyanates, thiocyanates, nitriles and epinitriles. The GSLs hydrolytic products are volatile compounds, which are known to exhibit bioactivities like antioxidant, fungicidal, bioherbicidal and anticancer. Among the Brassicaceae family, Brassica juncea is very well known for high content of GSLs. In the present study, the isolation of volatile oil of B. juncea var. raya was done by hydrodistillation method using clevenger apparatus and further there extraction was done by solvents ethyl acetate and dichloromethane. The volatile compounds present in the extract were analysed by gas chromatography/gas chromatography-mass spectrometry (GC/GC-MS). Fatty acid esters, sulphur and/or nitrogen compounds, carbonyl compounds and some other volatile compounds were also identified. Besides the analytical studies, the extracts were analysed for their bioactivities including radical scavenging activity by using DNA nicking assay and cytotoxic effect using different human cancer cell lines viz. breast (MCF-7 and MDA-MB-231), prostate (PC-3), lung (A-549), cervix (HeLa) and colon (HCT116) by MTT assay. The oil extracts were efficiently able to reduce the increase of cancer cells in a dose-dependent manner. Among all cell lines, the most effective anticancer activity was observed in case of breast (MCF-7) cancer cell line. So, MCF-7 cells were used for further mechanistic studies for analysing the mechanism of anticancer activity. Confocal microscopy was done for analysing morphological changes in the cells and the images confirmed the features typical of apoptosis. For evaluating the mode of cell death, spectrofluorometric determination of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) was done. The volatile oil extract treated MCF-7 cells had a significant increase in number of ROS, also there was a rise in percentage of cells with increased disruption of MMP. So, the present study marks necessary indication that B. juncea (raya) oil extracts significantly induces apoptosis in all the above mentioned cancer cells lines through a ROS-mediated mitochondrial pathway and thus play a remarkable role in death of cancer cells.

Structures of isothiocyanates attributed to reactive oxygen species generation and microtubule depolymerization in HepG2 cells

The structure of the isothiocyanates (ITCs)-erucin, sulforaphane, erysolin, sulforaphene, and phenethyl isothiocyanate-were assessed as well as their respective in vitro anticancer activity on the hepatocellular carcinoma cell line HepG2. All of these ITCs induced both apoptotic and necrotic cell death. FTIR analysis indicated that the ITCs caused changes in cellular components comparable to vinblastine. Despite no observable effect on DNA, the ITCs all induced generation of intracellular reactive oxygen species (ROS) and suppressed microtubule polymerization. The variation in sulfur oxidation states and the presence of an aromatic ring on the ITC side chain affected microtubule depolymerization and intracellular ROS generation, leading to apoptotic and necrotic cancer cell death. Knowing the influences of structural variations of the ITC side chain would be useful for selecting the more potent ITCs (i.e., erysolin) for the design and development of effective chemopreventive agents.

Low penetrance genetic polymorphisms as potential biomarkers for colorectal cancer predisposition

Colorectal cancer is a leading form of cancer in both males and females. Early detection of individuals at risk of colorectal cancer allows proper treatment and management of the disease to be implemented, which can potentially reduce the burden of colorectal cancer incidence, morbidity and mortality. In recent years, the role of genetic susceptibility factors in mediating predisposition to colorectal cancer has become more and more apparent. Identification of high-frequency, low-penetrance genetic polymorphisms associated with the cancer has therefore emerged as an important approach which can potentially aid prediction of colorectal cancer risk. However, the overwhelming amount of genetic epidemiology data generated over the past decades has made it difficult for one to assimilate the information and determine the exact genetic polymorphisms that can potentially be used as biomarkers for colorectal cancer. This review comprehensively consolidates, based primarily on results from meta-analyses, the recent progresses in the search of colorectal cancer-associated genetic polymorphisms, and discusses the possible mechanisms involved.

Untargeted Metabolomic Screen Reveals Changes in Human Plasma Metabolite Profiles Following Consumption of Fresh Broccoli Sprouts

SCOPE

Several lines of evidence suggest that the consumption of cruciferous vegetables is beneficial to human health. Yet, underlying mechanisms and key molecular targets that are involved with achieving these benefits in humans are still not fully understood. To accelerate this research, we conduct a human study to identify potential molecular targets of crucifers for further study. This study aims to characterize plasma metabolite profiles in humans before and after consuming fresh broccoli sprouts (a rich dietary source of bioactive sulforaphane).

METHODS AND RESULTS

Ten healthy adults consume fresh broccoli sprouts (containing 200 μmol sulforaphane equivalents) at time 0 and provide blood samples at 0, 3, 6, 12, 24, and 48 h. An untargeted metabolomics screen reveals that levels of several plasma metabolites are significantly different before and after sprout intake, including fatty acids (14:0, 14:1, 16:0, 16:1, 18:0, and 18:1), glutathione, glutamine, cysteine, dehydroepiandrosterone, and deoxyuridine monophosphate. Evaluation of all time points is conducted using paired t-test (R software) and repeated measures analysis of variance for a within-subject design (Progenesis QI).

CONCLUSION

This investigation identifies several potential molecular targets of crucifers that may aid in studying established and emerging health benefits of consuming cruciferous vegetables and related bioactive compounds.

Chemoprevention with isothiocyanates - From bench to bedside

Isothiocyanates (ITCs) are naturally occurring hydrolization products from glucosinolates (GLSs) in brassicaceae and in epidemiological studies their intake has been weakly to moderately inversely correlated with the risk of colorectal cancer, prostate cancer and lung cancer. Numerous preclinical studies demonstrate chemopreventive mode of actions of ITCs, mainly related to a.) detoxification (induction of phase II enzymes), b.) anti-inflammatory properties by down-regulation of NFkappaB activity, c.) cyclin-mediated cell cycle arrest and d.) epigenetic modulation by inhibition of histone deacetylase activity. First prospective clinical trials were promising in patients with risk of prostate cancer recurrence. The glutathione-S-transferase gene expression seems to play a major role in the individual susceptibility towards ITCs. Safety issues are widely unclear and should be more addressed in future studies because ITCs can, in low concentrations, compromise the function of human immune cells and might impair genome stability.

Bioactivity of Olive Oil Phenols in Neuroprotection

Neurological disorders such as stroke, Alzheimer’s and Parkinson’s diseases are associated with high morbidity and mortality, and few or no effective options are available for their treatment. These disorders share common pathological characteristics like the induction of oxidative stress, abnormal protein aggregation, perturbed Ca²⁺ homeostasis, excitotoxicity, inflammation and apoptosis. A large body of evidence supports the beneficial effects of the Mediterranean diet in preventing neurodegeneration. As the Mediterranean diet is characterized by a high consumption of extra-virgin olive oil it has been hypothesized that olive oil, and in particular its phenols, could be responsible for the beneficial effect of the Mediterranean diet. This review provides an updated vision of the beneficial properties of olive oil and olive oil phenols in preventing/counteracting both acute and chronic neurodegenerative diseases.

Anti-inflammatory effects of 1-isothiocyanato-7-(methylsulfonyl) heptane by suppressing the NFκ-B signaling pathway

The anti-inflammatory roles of I7456 (1-isothiocyanato-7-(methylsulfonyl) heptane or 7-methylsulfonylheptyl isothiocyanate), a plant-derived and sulfur-containing isothiocyanate, were investigated. When macrophage cells (RAW 264.7) were challenged with lipopolysaccharide (LPS), nitric oxide (NO) increased. However, NO was remarkably reduced upon I7456 treatment. I7456 strongly reduced the expression of IL-6, IL-10, IL-1β, and iNOS. Interestingly, heme oxygenase-1 (HO-1) was strongly induced without LPS challenge. LPS-induced NFκ-B (nuclear factor kappa-light-chain-enhancer of activated B cells) translocation into the nucleus was inhibited by I7456 in a dose-dependent manner. I7456 markedly reduced the phosphorylation level of IκB, and NFκ-B remained inactivated. I7456 could play important roles in anti-inflammatory responses and have implications for anticancer treatments.

Comparison of short- and long-term exposure effects of cruciferous and apiaceous vegetables on carcinogen metabolizing enzymes in Wistar rats

Cruciferous and apiaceous vegetables may be chemopreventive due to their ability to modulate carcinogen-metabolizing enzymes but whether the effects on such enzymes are sustained over time is unknown. To examine the short- and long-term effects of the vegetables, rats were fed one of four diets for 7, 30, or 60 d: AIN-93G, CRU (21% cruciferous vegetables-fresh broccoli, green cabbage, watercress), API (9% apiaceous vegetables - fresh parsnips, celery), or API + CRU (10.5% CRU + 4.5% API). Although CRU increased activity and protein expression of cytochrome P450 (CYP) 1A1 and CYP1A2 after 7 d, only activity was sustained after 30 and 60 d. There was a trend towards an interaction between the length of feeding period and CRU for CYP1A1 activity; activity increased with greater time of feeding. API increased CYP1A2 activity but decreased sulfotransferase 1A1 activity after 7 d, although not at later times. Altogether, increased CYP1A activity by CRU was maintained with long term feeding while protein amount decreased, suggesting influence by mechanisms other than, or in addition to, transcriptional regulation. Thus, response patterns and interactions with length of feeding may differ, depending upon the types of vegetables and enzymes, requiring caution when interpreting the results of short-term feeding studies.

Phenethyl isothiocyanate suppresses cancer stem cell properties in vitro and in a xenograft model

BACKGROUND

Cancer stem cells (CSCs) are a subset of cells within the bulk of a tumor that have the ability to self-renew and differentiate, and are thus associated with cancer invasion, metastasis, and recurrence. Phenethyl isothiocyanate (PEITC) is a natural compound found in cruciferous vegetables such as broccoli and is used as a cancer chemopreventive agent; however, its effects on CSCs are little known.

PURPOSE

To evaluate the effect of PEITC on CSCs in this study by examining CSC properties.

METHODS

NCCIT human embryonic carcinoma cells were treated with PEITC, and the expression of pluripotency factors Oct4, Sox-2, and Nanog were evaluated by luciferase assay and western blot. Effect of PEITC on self-renewal capacity and clonogenicity were assessed with the sphere formation, soft agar assay, and clonogenic assay in an epithelial cell adhesion molecule (EpCAM)-expressing CSC model derived from HCT116 colon cancer cells using a cell sorting system. The effect of PEITC was also investigated in a mouse xenograft model obtained by injecting nude mice with EpCAM-expressing cells.

RESULTS

We found that PEITC treatment suppressed expression of the all three pluripotency factors in the NCCIT cells, in which pluripotency factors are highly expressed. Moreover, PEITC suppressed the self-renewal capacity and clonogenicity in the EpCAM-expressing CSC model. EpCAM was used as a specific CSC marker in this study. Importantly, PEITC markedly suppressed both tumor growth and expression of three pluripotency factors in a mouse xenograft model.

CONCLUSION

These results demonstrate that PEITC might be able to slow down or prevent cancer recurrence by suppressing CSC stemness.

Functional foods and their role in cancer prevention and health promotion: a comprehensive review

Following cardiovascular disease, cancer is the second leading cause of death in most affluent countries. The 13.3 million new cases of cancer in 2010 were predicted to cost US$ 290 billion, but the total costs were expected to increases to US$ 458 billion in the year 2030 on basis of World Economic Forum in 2011. More than half of all cancer cases and deaths worldwide are consider being preventable. From its inception, the disease control priorities series has focused attention on delivering efficacious health interventions that can result in dramatic reductions in mortality and disability at relatively modest cost. The approach has been multidisciplinary, and the recommendations have been evidence-based, scalable, and adaptable in multiple settings. Better and more equitable health care is the shared responsibility of governments and international agencies, public and private sectors, and societies and individuals, and all of these partners have been involved in the development of the series. Functional foods are foods and food components that supply health benefits beyond basic nutrition. It's-believed these functional foods do more than simply provide nutrients because they help to maintaining health and thereby reducing the risk of disease. There are some reported evidences showing association between functional foods and cancer. For example, S-ally cysteine of garlic and lycopene from tomatoes in combination form suppressed the development of chemically induced gastric cancer by modulation of apoptosis-associated proteins (reduced Bcl-2/Bax ratio and up-regulation of Bim and caspases 8 and 3) at considerably lower intakes than when these substances were given in isolation. Similarly, vitamin D3 with genistein in combination form precipitated a growth inhibition of prostate cancer cells at much lower concentration than when these substances were provided individually. There are very few studies conducted worldwide to see the effects of functional foods on health or cancer or related states. This review, presents the complex patterns of cancer incidence and death around the world and evidence on effective and cost-effective ways to control cancers. The evaluation of cancer will indicate where cancer treatment is ineffective and wasteful, and offer alternative cancer care packages that are cost-effective and suited to low-resource settings. In the present paper, cancer prevention by functional foods is reviewed and the possible mechanisms of action are described.

The impact of cruciferous vegetable isothiocyanates on histone acetylation and histone phosphorylation in bladder cancer

Cruciferous vegetable intake is associated with reduced risk of bladder cancer, yet mechanisms remain unclear. Cruciferous vegetable isothiocyanates (ITCs), namely sulforaphane (SFN) and erucin (ECN), significantly inhibit histone deacetylase (HDAC) activity in human bladder cancer cells representing superficial to invasive biology (59-83% inhibition with 20μM, 48h treatment), and in bladder cancer xenografts (59±3% ECN inhibition). Individual HDACs inhibited by SFN and ECN include HDACs 1, 2, 4 and 6. Interestingly, global acetylation status of histones H3 or H4 remain unaltered. The interplay between HDAC inhibition and modest modulation of AcH3 and AcH4 status is partially explained by decreased histone acetyl transferase activity (48.8±5.3%). In contrast, a significant decrease in phosphorylation status of all isoforms of histone H1 was observed, concomitant with increased phosphatase PP1β and PP2A activity. Together, these findings suggest that ITCs modulate histone status via HDAC inhibition and phosphatase enhancement. This allows for reduced levels of histone H1 phosphorylation, a marker correlated with human bladder cancer progression. Therefore, ITC-mediated inhibition of histone H1 phosphorylation presents a novel direction of research in elucidating epidemiological relationships and supports future food-based prevention strategies.

SIGNIFICANCE

Collectively, our findings suggest that the cruciferous vegetable isothiocyanates: sulforaphane (SFN) and erucin (ECN), impact histones status in bladder cancer cells by modulating specific HDACs and HATs, and enhancing phosphatase activity, resulting in reduction of histone H1 phosphorylation. These findings are significant due to the fact that our previous work positively correlated histone H1 phosphorylation with bladder cancer carcinogenesis and progression. Therefore, we propose that SFN and ECN may inhibit bladder carcinogenesis via epigenetic modulation of gene expression associated with histone H1 phosphorylation. These efforts may elucidate biomarkers useful in epidemiologic studies related to cruciferous vegetable intake and cancer risk or provide intermediate biomarkers for food-based clinical intervention studies in high-risk cohorts.

Impact of Phytochemicals and Dietary Patterns on Epigenome and Cancer

Cancer remains one of the leading causes of death around the world. Initially it is recognized as a genetic disease, but now it is known to involve epigenetic abnormalities along with genetic alterations. Epigenetics refers to heritable changes that are not encoded in the DNA sequence itself, but play an important role in the control of gene expression. It includes changes in DNA methylation, histone modifications, and RNA interference. Although it is heritable, environmental factors such as diet could directly influence epigenetic mechanisms in humans. This article will focus on the role of dietary patterns and phytochemicals that have been demonstrated to influence the epigenome and more precisely histone and non-histone proteins modulation by acetylation that helps to induce apoptosis and phosphorylation inhibition, which counteracts with cells proliferation. Recent developments discussed here enhance our understanding of how dietary intervention could be beneficial in preventing or treating cancer and improving health outcomes.

Simultaneous determination of individual isothiocyanates in plant samples by HPLC-DAD-MS following SPE and derivatization with N-acetyl-l-cysteine

The procedure for the isothiocyanates (ITCs) determination that involves derivatization with N-acetyl-l-cysteine (NAC) and separation by HPLC was developed. Prior to derivatization, plant ITCs were isolated and purified using solid-phase extraction (SPE). The optimum conditions of derivatization are: 500μL of isopropanolic eluate obtained by SPE combined with 500μL of derivatizing reagent (0.2M NAC and 0.2M NaHCO3 in water) and reaction time of 1h at 50°C. The formed dithiocarbamates are directly analyzed by HPLC coupled with diode array detector and mass spectrometer if required. The method was validated for nine common natural ITCs. Calibration curves were linear (R(2)⩾0.991) within a wide range of concentrations and limits of detection were below 4.9nmol/mL. The recoveries were in the range of 83.3-103.7%, with relative standard deviations <5.4%. The developed method has been successfully applied to determine ITCs in broccoli, white cabbage, garden cress, radish, horseradish and papaya.

Sulforaphene suppresses growth of colon cancer-derived tumors via induction of glutathione depletion and microtubule depolymerization

SCOPE

Cruciferous vegetables harbor a number of isothiocyanates that have been recognized for their cancer-related properties. Out of these, sulforaphene (a naturally occurring derivative of sulforaphane) has received little attention in studies of colon cancer and its mechanism of action remains to be elucidated.

METHODS AND RESULTS

We observed that sulforaphene inhibited growth of human colon cancer cell lines HCT116, HT-29, KM12, SNU-1040, and DLD-1, while exhibiting negligible toxicity toward nonmalignant cells. Sulforaphene induced G2/M phase cell cycle arrest and apoptosis of colon cancer cells analyzed by flow cytometry, concomitant with phosphorylation of CDK1 and CDC25B at inhibitory sites, and upregulation of the p38 and JNK pathways. It was further determined that sulforaphene is a potent inhibitor of microtubule polymerization while generating reactive oxygen species via the depletion of glutathione. These observations further extended into inhibitory effects against colon tumor growth in a mouse xenograft model.

CONCLUSION

These findings demonstrate that sulforaphene may contribute to the anti-tumor effects of cruciferous vegetables that contain sulforaphene and other isothiocyanates.

The synergistic effect between the Mediterranean diet and GSTP1 or NAT2 SNPs decreases breast cancer risk in Greek-Cypriot women

PURPOSE

Xenobiotic metabolism is related to the interplay between diet and breast cancer (BC) risk. This involves detoxification enzymes, which are polymorphic and metabolise various dietary metabolites. An important characteristic of this pathway is that chemoprotective micronutrients can act not only as substrates but also as inducers for these enzymes. We investigated whether functional GSTP1 (p.Ile105Val-rs1695), NAT2 (590G>A-rs1799930) SNPs and GSTM1 and GSTT1 deletion polymorphisms could modulate the effect of the Mediterranean diet (MD) on BC risk, in Greek-Cypriot women.

METHODS

Genotyping was performed on women from the MASTOS case-control study of BC in Cyprus. A 32-item food-frequency questionnaire was used to obtain dietary intake information. A dietary pattern, which closely resembles the MD (high loadings of vegetables, fruit, legumes and fish), was previously derived with principal component analysis and was used as our dietary variable.

RESULTS

GSTT1 null genotype increased BC risk compared with the homozygous non-null GSTT1 genotype (OR 1.21, 95 % CI 1.01-1.45). Increasing adherence to the MD reduced BC risk in women with at least one GSTP1 Ile allele (OR for Ile/Ile = 0.84, 95 % CI 0.74-0.95, for Ile/Val = 0.73, 95 % CI 0.62-0.85) or one NAT2 590G allele (OR for 590 GG = 0.73, 95 % CI 0.63-0.83, for 590 GA = 0.81, 95 % CI 0.70-0.94). p interaction values were not, however, statistically significant.

CONCLUSION

The homozygous null GSTT1 genotype could be a risk allele for BC among Greek-Cypriot women. The anticarcinogenic effects of the high adherence to MD against BC risk could also be further enhanced when combined with the wild-type alleles of the detoxification GSTP1 or NAT2 SNPs.

Influences of diet and the gut microbiome on epigenetic modulation in cancer and other diseases

Epigenetic modulation of gene activity occurs in response to non-genetic factors such as body weight status, physical activity, dietary factors, and environmental toxins. In addition, each of these factors is thought to affect and be affected by the gut microbiome. A primary mechanism that links these various factors together in mediating control of gene expression is the production of metabolites that serve as critical cofactors and allosteric regulators of epigenetic processes. Here, we review the involvement of the gut microbiota and its interactions with dietary factors, many of which have known cellular bioactivity, focusing on particular epigenetic processes affected and the influence they have on human health and disease, particularly cancer and response to treatment. Advances in DNA sequencing have expanded the capacity for studying the microbiome. Combining this with rapidly improving techniques to measure the metabolome provides opportunities to understand complex relationships that may underlie the development and progression of cancer as well as treatment-related sequelae. Given broad reaching and fundamental biology, both at the cellular and organismal levels, we propose that interactive research programs, which utilize a wide range of mutually informative experimental model systems—each one optimally suited for answering particular questions—provide the best path forward for breaking ground on new knowledge and ultimately understanding the epigenetic significance of the gut microbiome and its response to dietary factors in cancer prevention and therapy.

Glucosinolate-derived isothiocyanates impact mitochondrial function in fungal cells and elicit an oxidative stress response necessary for growth recovery

Glucosinolates are brassicaceous secondary metabolites that have long been considered as chemical shields against pathogen invasion. Isothiocyanates (ITCs), are glucosinolate-breakdown products that have negative effects on the growth of various fungal species. We explored the mechanism by which ITCs could cause fungal cell death using Alternaria brassicicola, a specialist Brassica pathogens, as model organism. Exposure of the fungus to ICTs led to a decreased oxygen consumption rate, intracellular accumulation of reactive oxygen species (ROS) and mitochondrial-membrane depolarization. We also found that two major regulators of the response to oxidative stress, i.e., the MAP kinase AbHog1 and the transcription factor AbAP1, were activated in the presence of ICTs. Once activated by ICT-derived ROS, AbAP1 was found to promote the expression of different oxidative-response genes. This response might play a significant role in the protection of the fungus against ICTs as mutants deficient in AbHog1 or AbAP1 were found to be hypersensitive to these metabolites. Moreover, the loss of these genes was accompanied by a significant decrease in aggressiveness on Brassica. We suggest that the robust protection response against ICT-derived oxidative stress might be a key adaptation mechanism for successful infection of host plants by Brassicaceae-specialist necrotrophs like A. brassicicola.

4-Methylthiobutyl isothiocyanate (Erucin) from rocket plant dichotomously affects the activity of human immunocompetent cells

Isothiocyanates (ITC) from the Brassicaceae plant family are regarded as promising for prevention and treatment of cancer. However, experimental settings consider their therapeutic action without taking into account the risk of unwanted effects on healthy tissues. In the present study we investigated the effects of Eruca sativa seed extract containing MTBITC (Erucin) and pure Erucin from rocket plant on healthy cells of the human immune system in vitro. Hereby, high doses of the plant extract as well as of Erucin inhibited cell viability of human lymphocytes via induction of apoptosis to comparable amounts. Non-toxic low concentrations of the plant extract and pure Erucin altered the expression of the interleukin (IL)-2 receptor but did not affect further T cell activation, proliferation and the release of the effector molecules interferon (IFN)-gamma and IL-2 of T-lymphocytes. However, the activity of NK-cells was significantly reduced by non-toxic concentrations of the plant extract and pure Erucin. These results indicate that the plant extract and pure Erucin interfere with the function of human T lymphocytes and decreases the activity of NK-cells in comparable concentrations. Long-term clinical studies with ITC-enriched plant extracts from Brassicaceae should take this into account.