A major inducer of anticarcinogenic protective enzymes from broccoli: isolation and elucidation of structure

Isothiocyanates as Tubulin Polymerization Inhibitors-Synthesis and Structure-Activity Relationship Studies

Among the various substances that interfere with the microtubule formation process, isothiocyanates (ITCs) are the group of compounds for which the binding mode and mechanism of action have not yet been explained. To better understand the structure-activity relationship of tubulin-isothiocyanate interactions, we designed and synthesized a series of sixteen known and novel, structurally diverse ITCs, including amino acid ester-derived isothiocyanates, bis-isothiocyanates, analogs of benzyl isothiocyanate, and phosphorus analogs of sulforaphane. All synthesized compounds and selected natural isothiocyanates (BITC, PEITC, AITC, and SFN) were tested in vitro to evaluate their antiproliferative activity, tubulin polymerization inhibition potential, and influence on cell cycle progression. The antiproliferative activity of most of the newly tested compounds exceeded the action of natural isothiocyanates, with four structures being more potent as tubulin polymerization inhibitors than BITC. As a confirmation of anti-tubulin activity, the correlation between polymerization inhibition and cell cycle arrest in the G2/M phase was observed for the most active compounds. In light of the biological results indicating significant differences in the impact of structurally diverse isothiocyanate on tubulin polymerization, in silico analysis was conducted to analyze the possible mode of isothiocyanate-tubulin binding and to show how it can influence the polymerization reaction.

Preclinical investigations on broccoli-derived sulforaphane for the treatment of ophthalmic disease

Vision loss causes a significant burden on individuals and communities on a financial, emotional and social level. Common causes include age-related macular degeneration (AMD), diabetic retinopathy (DR), glaucoma and retinitis pigmentosa (RP; also known as 'rod-cone dystrophy'). As the population continues to grow and age globally, an increasing number of people will experience vision loss. Hence, there is an urgent need to develop therapies that can curb early pathological events. The broccoli-derived compound, sulforaphane (SFN), is reported to have multiple health benefits and modes of action. In this review, we outline the preclinical findings on SFN in ocular diseases and discuss the future clinical testing of this compound.

The Rationale for Sulforaphane Favourably Influencing Gut Homeostasis and Gut-Organ Dysfunction: A Clinician's Hypothesis

Given the increasing scientific, clinical and consumer interest in highly prevalent functional gastrointestinal disorders, appropriate therapeutic strategies are needed to address the many aspects of digestive dysfunction. Accumulating evidence for the crucifer-derived bioactive molecule sulforaphane in upstream cellular defence mechanisms highlights its potential as a therapeutic candidate in targeting functional gastrointestinal conditions, as well as systemic disorders. This article catalogues the evolution of and rationale for a hypothesis that multifunctional sulforaphane can be utilised as the initial step in restoring the ecology of the gut ecosystem; it can do this primarily by targeting the functions of intestinal epithelial cells. A growing body of work has identified the colonocyte as the driver of dysbiosis, such that targeting gut epithelial function could provide an alternative to targeting the microbes themselves for the remediation of microbial dysbiosis. The hypothesis discussed herein has evolved over several years and is supported by case studies showing the application of sulforaphane in gastrointestinal disorders, related food intolerance, and several systemic conditions. To the best of our knowledge, this is the first time the effects of sulforaphane have been reported in a clinical environment, with several of its key properties within the gut ecosystem appearing to be related to its nutrigenomic effects on gene expression.

Bioavailable Sulforaphane Quantitation in Plasma by LC-MS/MS Is Enhanced by Blocking Thiols

Quantifying sulforaphane (SFN) and its thiol metabolites in biological samples using liquid chromatography-tandem mass spectrometry is complicated by SFN's electrophilic nature and the facile dissociation of SFN-thiol conjugates. SFN can be lost during sample preparation due to conjugation with protein thiols, which are precipitated and discarded. We observe that only 32 ± 3% of SFN is recovered 2 h after spiking into fetal bovine serum. The SFN-glutathione conjugate prepared at 10 mM in 0.1% formic acid in water (pH 3) dissociated by approximately 95% to free SFN, highlighting the difficulty in preparing thiol metabolite standards. We used the alkylating agent iodoacetamide (IAA) to both release SFN from protein thiols and force the dissociation of SFN metabolites. This thiol-blocking method increased SFN percent recovery from serum from 32 to 94 ± 5%, with a 4.7 nM method limit of quantitation. Applying the method to clinical samples, SFN concentrations were on average 6 times greater than when IAA was omitted. The IAA thiol-blocking method streamlines the analysis of bioavailable SFN in plasma samples.

New Insight into the Potential Protective Function of Sulforaphene against ROS-Mediated Oxidative Stress Damage In Vitro and In Vivo

Sulforaphene (SFE) is a kind of isothiocyanate isolated from radish seeds that can prevent free-radical-induced diseases. In this study, we investigated the protective effect of SFE on oxidative-stress-induced damage and its molecular mechanism in vitro and in vivo. The results of cell experiments show that SFE can alleviate D-gal-induced cytotoxicity, promote cell cycle transformation by inhibiting the production of reactive oxygen species (ROS) and cell apoptosis, and show a protective effect on cells with H2O2-induced oxidative damage. Furthermore, the results of mice experiments show that SFE can alleviate D-galactose-induced kidney damage by inhibiting ROS, malondialdehyde (MDA), and 4-hydroxyalkenals (4-HNE) production; protect the kidney against oxidative stress-induced damage by increasing antioxidant enzyme activity and upregulating the Nrf2 signaling pathway; and inhibit the activity of pro-inflammatory factors by downregulating the expression of Toll-like receptor 4 (TLR4)-mediated inflammatory response. In conclusion, this research shows that SFE has antioxidant effects, providing a new perspective for studying the anti-aging properties of natural compounds.

Optimization of 3-aminotetrahydrothiophene 1,1-dioxides with improved potency and efficacy as non-electrophilic antioxidant response element (ARE) activators

Activating NRF2-driven transcription with non-electrophilic small molecules represents an attractive strategy to therapeutically target disease states associated with oxidative stress and inflammation. In this study, we describe a campaign to optimize the potency and efficacy of a previously identified bis-sulfone based non-electrophilic ARE activator 2. This work identifies the efficacious analog 17, a compound with a non-cytotoxic profile in IMR32 cells, as well as ARE activators 18 and 22, analogs with improved cellular potency. In silico drug-likeness prediction suggested the optimized bis-sulfones 17, 18, and 22 will likely be of pharmacological utility.

Effect of sulforaphane on long-term storage of rabbit semen

In this study, it was aimed to determine the effect of sulforaphane (SFN) on rabbit semen cryopreservation. Semen collected from animals was divided into 5 equal volumes as Control, SFN 5 µM, SFN 10 µM, SFN 25 µM and SFN 50 µM groups. Afterwards, semen analyzes were performed. According to our results, there was no statistical difference between the groups at 4°C. However after freezing thawing, the highest total motility, progressive motility and rapid spermatozoa rate was seen in the 10 µM SFN group, while the lowest was observed in the 50 µM SFN group (P<0.05). Static sperm ratio was highest in the 50 µM group, while the lowest was observed in the 10 µM SFN group. When flow cytometry results examined the rate of acrosomal damaged and dead sperm was the lowest in the 10 µM SFN group, a statistical difference was observed between the control group (P<0.05). The highest rate of sperm with high mitochondrial membrane potential was seen in the 5 µM SFN and 10 µM SFN groups. Apoptosis and ROS rates were found to be lower in the experimental groups compared to the control groups (P<0.05). As a result, SFN supplementation at a dose of 10 µM increased the quality of sperm in the freezing and thawing processes of rabbit semen. In conclusion, 10 µM SFN improved the quality of cryopreservation of rabbit semen.

Ferroptosis-modulating small molecules for targeting drug-resistant cancer: Challenges and opportunities in manipulating redox signaling

Ferroptosis is an iron-dependent cell death program that is characterized by excessive lipid peroxidation. Triggering ferroptosis has been proposed as a promising strategy to fight cancer and overcome drug resistance in antitumor therapy. Understanding the molecular interactions and structural features of ferroptosis-inducing compounds might therefore open the door to efficient pharmacological strategies against aggressive, metastatic, and therapy-resistant cancer. We here summarize the molecular mechanisms and structural requirements of ferroptosis-inducing small molecules that target central players in ferroptosis. Focus is placed on (i) glutathione peroxidase (GPX) 4, the only GPX isoenzyme that detoxifies complex membrane-bound lipid hydroperoxides, (ii) the cystine/glutamate antiporter system Xc - that is central for glutathione regeneration, (iii) the redox-protective transcription factor nuclear factor erythroid 2-related factor (NRF2), and (iv) GPX4 repression in combination with induced heme degradation via heme oxygenase-1. We deduce common features for efficient ferroptotic activity and highlight challenges in drug development. Moreover, we critically discuss the potential of natural products as ferroptosis-inducing lead structures and provide a comprehensive overview of structurally diverse biogenic and bioinspired small molecules that trigger ferroptosis via iron oxidation, inhibition of the thioredoxin/thioredoxin reductase system or less defined modes of action.

Sulforaphane and Its Protective Role in Prostate Cancer: A Mechanistic Approach

The increasing incidence of prostate cancer worldwide has spurred research into novel therapeutics for its treatment and prevention. Sulforaphane, derived from broccoli and other members of the Brassica genus, is a phytochemical shown to have anticancer properties. Numerous studies have shown that sulforaphane prevents the development and progression of prostatic tumors. This review evaluates the most recent published reports on prevention of the progression of prostate cancer by sulforaphane in vitro, in vivo and in clinical settings. A detailed description of the proposed mechanisms of action of sulforaphane on prostatic cells is provided. Furthermore, we discuss the challenges, limitations and future prospects of using sulforaphane as a therapeutic agent in treatment of prostate cancer.

Research progress on the utilization technology of broccoli stalk, leaf resources, and the mechanism of action of its bioactive substances

Broccoli is a nutritious vegetable. It is high in protein, minerals, and vitamins. Also, it possesses antioxidant activities and is beneficial to the human body. Due to its active effect, broccoli is widely accepted by people in daily life. However, in terms of current utilization, only its florets are consumed as vegetables, while more than half of its stalks and leaves are not utilized. The stalks and leaves contain not only nutrients but also bioactive substances with physiologically regulating properties. Therefore research into the action and mechanism of its bioactive substances as well as its development and utilization technology will make contributions to the further promotion of its resource development and utilization. As a theoretical foundation for the resource utilization of broccoli stalks and leaves, this report will review the distribution and consumption of broccoli germplasm resources, the mechanism of action of bioactive substances, and innovative methods for their exploitation.

Nrf2 Activation Does Not Protect from Aldosterone-Induced Kidney Damage in Mice

Nuclear factor erythroid 2-related factor 2 (Nrf2) is downregulated in chronic kidney disease (CKD). Activation of Nrf2 might be a therapeutic option in CKD. Here we investigate the effect of Nrf2 activation on aldosterone (Aldo)-induced renal injury. Wild-type (WT) mice, transgenic Keap1 hypomorphic (Nrf2ꜛ, genotype results in upregulation of Nrf2 expression) mice and WT mice treated with the Nrf2 activator sulforaphane (Sulf) received Aldo for 4 weeks. In Aldo-treated mice, kidneys were significantly heavier and pathologically altered, reflected by increased urinary albumin levels and tissue damage. In Nrf2ꜛ-Aldo mice the tubule damage marker NGAL was significantly decreased. Increased oxidative damage markers (8-OHdG, 15-isoprostane F_2t) were measured in all Aldo-treated groups. Aldo-increased Nrf2 amounts were mainly found in the late tubule system. The amount of phosphorylated and thus putatively active Nrf2 was significantly increased by Aldo only in WT mice. However, expression of Nrf2 target genes NQO1 and HO1 was decreased in all Aldo-infused mice. GSK3β, which promotes Nrf2 degradation, was significantly increased in the kidneys of Aldo-treated WT mice. Neither genetic nor pharmacological Nrf2 activation was able to prevent oxidative injury induced by Aldo, probably due to induction of negative regulators of Nrf2.

Advances and challenges in therapeutic targeting of NRF2

Activation of the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) is emerging as an attractive therapeutic approach to counteract oxidative stress, inflammation, and metabolic imbalances. These processes underpin many chronic pathologies with unmet therapeutic needs, including neurodegenerative disorders and metabolic diseases. As the NRF2 field transitions into the clinical phase of its evolution, the need for an understanding of the factors influencing NRF2 pharmacology has never been greater. In this opinion article we describe the rationale for targeting NRF2, summarise the recent advances in drug development of NRF2 modulators, and reflect on the remaining challenges in realising the full clinical potential of NRF2 as a therapeutic target.

Sulforaphane attenuates cancer cell-induced atrophy of C2C12 myotubes

Cancer cachexia is common in many cancers and the loss of skeletal muscle mass compromises the response to therapies and quality of life. A contributing mechanism is oxidative stress and compounds able to attenuate it may be protective. Sulforaphane (SFN), a natural antioxidant in cruciferous vegetables, activates nuclear factor erythroid 2-related factor 2 (Nrf2) signaling to decrease oxidative stress. Although SFN has potential as a cancer therapeutic, whether it can attenuate muscle wasting in the absence or presence of chemotherapy is unknown. In healthy C2C12 myotubes, SFN administration for 48 h induced hypertrophy through increased myoblast fusion via Nrf2 and ERK signaling. To determine whether SFN could attenuate wasting induced by cancer cells, myotubes were cocultured with or without Colon-26 (C-26) cancer cells for 48 h and treated with 5-fluorouracil (5-FU, 5 µM) or vehicle (DMSO). SFN (10 µM) or DMSO was added for the final 24 h. Coculture with cancer cells in the absence and presence of 5-FU reduced myotube width by ∼30% (P < 0.001) and ∼20% (P < 0.01), respectively, which was attenuated by SFN (P < 0.05). Exposure to C-26 conditioned media reduced myotube width by 15% (P < 0.001), which was attenuated by SFN. Western immunoblotting and qRT-PCR confirmed activation of Nrf2 signaling and antioxidant genes. Coadministration of Nrf2 inhibitors (ML-385) or MEK inhibitors (PD184352) revealed that SFN's attenuation of atrophy was blocked by ERK inhibition. These data support the chemoprotective and antioxidative function of SFN in myotubes, highlighting its therapeutic potential for cancer-related muscle wasting.

Development and optimization of nanoparticles loaded with erucin, a dietary isothiocyanate isolated from Eruca sativa: Antioxidant and antiproliferative activities in ehrlich-ascites carcinoma cell line

The study on Erucin (ER) has gained interest of nutraceutical and pharmaceutical industries because of its anti-cancer properties. Erucin is an isothiocyanate obtained from the seeds of Eruca sativa which possess certain drawbacks such as poor aqueous solubility and bioavailability. Therefore, the present study aimed at developing ER-cubosomes (CUB) by solvent evaporation technique followed by applying Central Composite Design to optimize ER loaded cubosomes. For this purpose, independent variables selected were Monoolein (MO) as lipid and Pluronic-84 (P-84) as a stabilizer whereas dependent variables were particle size, percentage of ER loading and percentage of its entrapment efficiency. The cubosomal nanocarriers exhibited particle size in the range of 26 nm, entrapment efficiency of 99.12 ± 0.04% and drug loading of 3.96 ± 0.0001%. Furthermore, to investigate the antioxidant potential, we checked the effect of ER and ER-CUB by DNA nicking assay, DDPH assay and Phosphomolybdate assay, and results showed significant improvement in antioxidant potential for ER-CUB than ER. Similarly, ER-CUB showed enhanced anticancer activity with a marked reduction in IC50 value than ER in MTT assay. These results suggested that ER-CUB produced notable escalation in antioxidant potential and enhanced anticancer activity than ER.

Targeting cancer stem cells and signalling pathways through phytochemicals: A promising approach against colorectal cancer

BACKGROUND

Cancer stem cells (CSCs) are strongly associated with high tumourigenicity, chemotherapy or radiotherapy resistance, and metastasis and recurrence, particularly in colorectal cancer (CRC). Therefore, targeting CSCs may be a promising approach. Recently, discovery and research on phytochemicals that effectively target colorectal CSCs have been gaining popularity because of their broad safety profile and multi-target and multi-pathway modes of action.

PURPOSE

This review aimed to elucidate and summarise the effects and mechanisms of phytochemicals with potential anti-CSC agents that could contribute to the better management of CRC.

METHODS

We reviewed PubMed, EMBASE, Web of Science, Ovid, ScienceDirect and China National Knowledge Infrastructure databases from the original publication date to March 2022 to review the mechanisms by which phytochemicals inhibit CRC progression by targeting CSCs and their key signalling pathways. Phytochemicals were classified and summarised based on the mechanisms of action.

RESULTS

We observed that phytochemicals could affect the biological properties of colorectal CSCs. Phytochemicals significantly inhibit self-renewal, migration, invasion, colony formation, and chemoresistance and induce apoptosis and differentiation of CSCs by regulating the Wnt/β-catenin pathway (e.g., diallyl trisulfide and genistein), the phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin pathway (e.g., caffeic acid and piperlongumine), the neurogenic locus notch homolog protein pathway (e.g., honokiol, quercetin, and α-mangostin), the Janus kinase-signal transducer and activator of transcription pathway (e.g., curcumin, morin, and ursolic acid), and other key signalling pathways. It is worth noting that several phytochemicals, such as resveratrol, silibinin, evodiamine, and thymoquinone, highlight multi-target and multi-pathway effects in restraining the malignant biological behaviour of CSCs.

CONCLUSIONS

This review demonstrates the potential of targeted therapies for colorectal CSCs using phytochemicals. Phytochemicals could serve as novel therapeutic agents for CRC and aid in drug development.

Sulforaphane Ameliorates Hepatic Lipid Metabolism via Modulating Lipophagy In Vivo and In Vitro

Although sulforaphane (SFN) is reported to ameliorate the excessive accumulation of lipid droplets (LDs) in hepatocytes, its underlying mechanism remains unclear. This paper aims to investigate how SFN induces hepatic LD degradation via activating macroautophagy. High-fat diet and free fatty acids (FFAs) were used to induce excessive LD formation in hepatocytes in vivo and in vitro, respectively. SFN-induced macroautophagy was shown by the increased LC3 protein expression both (1.32 ± 0.18) in vivo and (2.43 ± 0.22) in vitro. The mRNA levels of Lc3 (1.99 ± 0.16), Atg4 (2.12 ± 0.23), Ulk1 (1.19 ± 0.12), Atg7 (1.25 ± 0.11), and Atg5 (0.81 ± 0.1) genes were elevated by SFN. SFN individually enhanced the localization of LC3 (0.41 ± 0.15), LAMP1 (0.66 ± 0.14), ATG7 (0.26 ± 0.08), and ATG5 (0.38 ± 0.09) with LDs, indicating the occurrence of lipophagy. In the components of LDs isolated from SFN treatment, the expressions of LC3, ATG7, and ATG5 protein were largely increased both in vivo and in vitro. LDs were visualized in autophagosomes which confirmed that the lipophagy was triggered by SFN. Moreover, SFN treatment improved the profile of FFAs which was characterized by increasing the FFAs in liver (total FFA: 261.51 ± 39.58 μM/g) and serum (total FFA: 967.59 ± 239.18 nM/mL). After silencing the nrf2 gene, ATG7 and ATG5 protein expressions were decreased and attenuated this induction by SFN. Nrf2 gene silencing inversely increased TG contents. In summary, SFN enhanced the LD degradation via stimulating lipophagy in a Nrf2-dependent manner.

Nrf2 and Oxidative Stress: A General Overview of Mechanisms and Implications in Human Disease

Organisms are continually exposed to exogenous and endogenous sources of reactive oxygen species (ROS) and other oxidants that have both beneficial and deleterious effects on the cell. ROS have important roles in a wide range of physiological processes; however, high ROS levels are associated with oxidative stress and disease progression. Oxidative stress has been implicated in nearly all major human diseases, from neurogenerative diseases and neuropsychiatric disorders to cardiovascular disease, diabetes, and cancer. Antioxidant defence systems have evolved as a means of protection against oxidative stress, with the transcription factor Nrf2 as the key regulator. Nrf2 is responsible for regulating an extensive panel of antioxidant enzymes involved in the detoxification and elimination of oxidative stress and has been extensively studied in the disease contexts. This review aims to provide the reader with a general overview of oxidative stress and Nrf2, including basic mechanisms of Nrf2 activation and regulation, and implications in various major human diseases.

Sulforaphane prevents and reverses allergic airways disease in mice via anti-inflammatory, antioxidant, and epigenetic mechanisms

Sulforaphane has been investigated in human pathologies and preclinical models of airway diseases. To provide further mechanistic insights, we explored L-sulforaphane (LSF) in the ovalbumin (OVA)-induced chronic allergic airways murine model, with key hallmarks of asthma. Histological analysis indicated that LSF prevented or reversed OVA-induced epithelial thickening, collagen deposition, goblet cell metaplasia, and inflammation. Well-known antioxidant and anti-inflammatory mechanisms contribute to the beneficial effects of LSF. Fourier transform infrared microspectroscopy revealed altered composition of macromolecules, following OVA sensitization, which were restored by LSF. RNA sequencing in human peripheral blood mononuclear cells highlighted the anti-inflammatory signature of LSF. Findings indicated that LSF may alter gene expression via an epigenetic mechanism which involves regulation of protein acetylation status. LSF resulted in histone and α-tubulin hyperacetylation in vivo, and cellular and enzymatic assays indicated decreased expression and modest histone deacetylase (HDAC) inhibition activity, in comparison with the well-known pan-HDAC inhibitor suberoylanilide hydroxamic acid (SAHA). Molecular modeling confirmed interaction of LSF and LSF metabolites with the catalytic domain of metal-dependent HDAC enzymes. More generally, this study confirmed known mechanisms and identified potential epigenetic pathways accounting for the protective effects and provide support for the potential clinical utility of LSF in allergic airways disease.

The role of nanomaterials in enhancing natural product translational potential and modulating endoplasmic reticulum stress in the treatment of ovarian cancer

Ovarian cancer, and particularly its most frequent type, epithelial ovarian carcinoma, constitutes one of the most dangerous malignant tumors among females. Substantial evidence has described the potential of phytochemicals against ovarian cancer. The effect of natural compounds on endoplasmic reticulum (ER) stress is of great relevance in this regard. In ovarian cancer, the accumulation of misfolded proteins in the ER lumen results in decompensated ER stress. This leads to deregulation in the physiological processes for the posttranslational modification of proteins, jeopardizes cellular homeostasis, and increases apoptotic signaling. Several metabolites and metabolite extracts of phytochemical origin have been studied in the context of ER stress in ovarian cancer. Resveratrol, quercetin, curcumin, fucosterol, cleistopholine, fucoidan, and epicatechin gallate, among others, have shown inhibitory potential against ER stress. The chemical structure of each compound plays an important role concerning its pharmacodynamics, pharmacokinetics, and overall effectiveness. Studying and cross-comparing the chemical features that render different phytochemicals effective in eliciting particular anti-ER stress actions can help improve drug design or develop multipotent combination regimens. Many studies have also investigated the properties of formulations such as nanoparticles, niosomes, liposomes, and intravenous hydrogel based on curcumin and quercetin along with some other phytomolecules in ovarian cancer. Overall, the potential of phytochemicals in targeting genetic mechanisms of ovarian cancer warrants further translational and clinical investigation.

Sulforaphane recovers cone function in an Nrf2-dependent manner in middle-aged mice undergoing RPE oxidative stress

PURPOSE

Sulforaphane (SFN) is an isothiocyanate derived from cruciferous vegetables that has therapeutic efficacy in numerous animal models of human disease, including mouse models of retinal degeneration. However, despite dozens of clinical trials, the compound remains to be tested as a clinical treatment for ocular disease. Numerous cellular activities of SFN have been identified, including the activation of Nrf2, a transcription factor that induces a battery of target gene products to neutralize oxidative and xenobiotic stresses. As Nrf2 expression and function reportedly decrease with aging, we tested whether the loss of the transcription factor limits the therapeutic efficacy of SFN against retinal degeneration.

METHODS

Six- to 8-month-old wild-type and Nrf2 knockout mice were treated with SFN beginning 1 month after ribozyme-mediated knockdown of superoxide dismutase 2 (SOD2) mRNA in the RPE. The impacts of MnSOD (the protein product of SOD2) knockdown and the efficacy of SFN were evaluated using a combination of electroretinography (ERG), spectral domain optical coherence tomography (SD-OCT), and postmortem histology.

RESULTS

SFN restored the ERG photopic b-wave suppressed by MnSOD loss in wild-type mice, but not in the Nrf2 knockout mice. In contrast, ERG scotopic a- and b-wave loss was not restored for either genotype. SFN significantly improved retinal thickness in the Nrf2 knockout mice with MnSOD knockdown, but this was not observed in the wild-type mice. In both genotypes, SFN treatment reduced morphological markers of RPE atrophy and degeneration, although these improvements did not correlate proportionally with functional recovery.

CONCLUSIONS

These findings highlight the capacity of SFN to preserve cone function, as well as the potential challenges of using the compound as a standalone treatment for age-related retinal degeneration under conditions associated with reduced Nrf2 function.

Plant-Derived Sulforaphane Suppresses Growth and Proliferation of Drug-Sensitive and Drug-Resistant Bladder Cancer Cell Lines In Vitro

Simple Summary

The natural compound sulforaphane is highly popular among tumor patients, since it is suggested to prevent oncogenesis and cancer progression. However, knowledge about its precise mode of action, particularly when drug resistance has been established, remains poor. The present study demonstrates the proliferation-blocking effects of SFN on a panel of drug-resistant bladder cancer cell lines.

Abstract

Combined cisplatin–gemcitabine (GC) application is standard for treating muscle-invasive bladder cancer. However, since rapid resistance to treatment often develops, many patients turn to supplements in the form of plant-based compounds. Sulforaphane (SFN), derived from cruciferous vegetables, is one such compound, and the present study was designed to investigate its influence on growth and proliferation in a panel of drug-sensitive bladder cancer cell lines, as well as their gemcitabine- and cisplatin-resistant counterparts. Chemo-sensitive and -resistant RT4, RT112, T24, and TCCSUP cell lines were exposed to SFN in different concentrations, and tumor growth, proliferation, and clone formation were evaluated, in addition to apoptosis and cell cycle progression. Means of action were investigated by assaying cell-cycle-regulating proteins and the mechanistic target of rapamycin (mTOR)/AKT signaling cascade. SFN significantly inhibited growth, proliferation, and clone formation in all four tumor cell lines. Cells were arrested in the G2/M and/or S phase, and alteration of the CDK–cyclin axis was closely associated with cell growth inhibition. The AKT/mTOR signaling pathway was deactivated in three of the cell lines. Acetylation of histone H3 was up-regulated. SFN, therefore, does exert tumor-suppressive properties in cisplatin- and gemcitabine-resistant bladder cancer cells and could be beneficial in optimizing bladder cancer therapy.

Phytochemicals in Skeletal Muscle Health: Effects of Curcumin (from Curcuma longa Linn) and Sulforaphane (from Brassicaceae) on Muscle Function, Recovery and Therapy of Muscle Atrophy

The mobility of the human body depends on, among other things, muscle health, which can be affected by several situations, such as aging, increased oxidative stress, malnutrition, cancer, and the lack or excess of physical exercise, among others. Genetic, metabolic, hormonal, and nutritional factors are intricately involved in maintaining the balance that allows proper muscle function and fiber recovery; therefore, the breakdown of the balance among these elements can trigger muscle atrophy. The study from the nutrigenomic perspective of nutritional factors has drawn wide attention recently; one of these is the use of certain compounds derived from foods and plants known as phytochemicals, to which various biological activities have been described and attributed in terms of benefiting health in many respects. This work addresses the effect that the phytochemicals curcumin from Curcuma longa Linn and sulforaphane from Brassicaceae species have shown to exert on muscle function, recovery, and the prevention of muscle atrophy, and describes the impact on muscle health in general. In the same manner, there are future perspectives in research on novel compounds as potential agents in the prevention or treatment of medical conditions that affect muscle health.

Potential of Sulforaphane and Broccoli Membrane Vesicles as Regulators of M1/M2 Human Macrophage Activity

Macrophages have emerged as important therapeutic targets in many human diseases. The aim of this study was to analyze the effect of broccoli membrane vesicles and sulphoraphane (SFN), either free or encapsulated, on the activity of human monocyte-derived M1 and M2 macrophage primary culture. Our results show that exposure for 24 h to SFN 25 µM, free and encapsulated, induced a potent reduction on the activity of human M1 and M2 macrophages, downregulating proinflammatory and anti-inflammatory cytokines and phagocytic capability on C. albicans. The broccoli membrane vesicles do not represent inert nanocarriers, as they have low amounts of bioactive compounds, being able to modulate the cytokine production, depending on the inflammatory state of the cells. They could induce opposite effects to that of higher doses of SFN, reflecting its hormetic effect. These data reinforce the potential use of broccoli compounds as therapeutic agents not only for inflammatory diseases, but they also open new clinical possibilities for applications in other diseases related to immunodeficiency, autoimmunity, or in cancer therapy. Considering the variability of their biological effects in different scenarios, a proper therapeutic strategy with Brassica bioactive compounds should be designed for each pathology.

Sulforaphane Enhances the Anticancer Properties of Paclitaxel in Two Human Derived Prostate Cancer Cell Lines.. [DOI: 10.21203/rs.3.rs-1552332/v2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background: In cancer therapy, combined treatment results in additive and synergistic outcomes and reduces the development of drug resistance in response to anticancer agents compared with monotherapy. We propose that when Paclitaxel (Taxol, PTX) is combined with Sulforaphane (SFN), may result in better treatment outcomes in prostate cancer. Understanding the mechanism of drug synergy, as opposed to simply knowing which drugs to combine, enables further optimization of advantageous drug interactions and can provide efficient therapeutic strategies in preclinical research. Methods: We measured apoptosis, cell cycle, and expression of Bax and Bcl2 in response to the PTX and SFN individual and combined treatments. Cell lines (PC-3) and (LNCaP), were individually treated with different concentrations of PTX, SFN, and its combination. Annexin V/PI positivity and data analysis were conducted using a flow cytometer and guava data acquisition and analysis software. Graph-Pad Prism 6, and Microsoft Excel software were used for statistical analyses and graphs generation. Student’s t-tests or one-way analysis of variance with Tukey’s correction were used to determine the significant difference between mono- and combination treatments.Results: The effect of the PTX or SFN treatments on reducing cell viability increased in a dose-dependent manner. Combined treatment enhanced PTX’s effects and reduced the EC50 values of both drugs compared to individual treatments. Flow cytometry analysis revealed that PTX or SFN treatments redistributed cell-cycle phases by inducing S-phase arrest and increasing apoptotic cell population in PC-3 cells. Such effects were enhanced in the PTX+SFN combination group. Interestingly, the necrotic cells were not affected by the combination treatments. Caspase-3 cleavage and morphological deformations of the cell nuclei are signs of apoptotic cell death; such parameters were examined by western blot and fluorescent microscopy in response to mono- and combination treatments.Conclusion: The PTX or SFN differentially modulated the expression of Bax and Bcl2 in PC-3 and LNCaP cell lines, and the combined treatment enhanced these effects in favor of cell apoptosis versus survival. Our data indicated that combination therapy of PTX and SFN significantly increased Bax protein expression and Bax: Bcl2 ratio compared to PTX or SFN individual treatments. Such findings will help develop new biomarkers and guide therapy choices.

Identification of the NRF2 transcriptional network as a therapeutic target for trigeminal neuropathic pain

Trigeminal neuralgia, historically dubbed the "suicide disease," is an exceedingly painful neurologic condition characterized by sudden episodes of intense facial pain. Unfortunately, the only U.S. Food and Drug Administration (FDA)-approved medication for trigeminal neuralgia carries substantial side effects, with many patients requiring surgery. Here, we identify the NRF2 transcriptional network as a potential therapeutic target. We report that cerebrospinal fluid from patients with trigeminal neuralgia accumulates reactive oxygen species, several of which directly activate the pain-transducing channel TRPA1. Similar to our patient cohort, a mouse model of trigeminal neuropathic pain also exhibits notable oxidative stress. We discover that stimulating the NRF2 antioxidant transcriptional network is as analgesic as inhibiting TRPA1, in part by reversing the underlying oxidative stress. Using a transcriptome-guided drug discovery strategy, we identify two NRF2 network modulators as potential treatments. One of these candidates, exemestane, is already FDA-approved and may thus be a promising alternative treatment for trigeminal neuropathic pain.

Immunomodulatory Effects of (R)-Sulforaphane on LPS-Activated Murine Immune Cells: Molecular Signaling Pathways and Epigenetic Changes in Histone Markers

The aim of this study was to explore the immunomodulatory effects of the natural enantiomer (R)-Sulforaphane (SFN) and the possible signaling pathways involved in an ex vivo model of LPS-stimulated murine peritoneal macrophages. Furthermore, we studied the epigenetic changes induced by (R)-SFN as well as the post-translational modifications of histone H3 (H3K9me3 and H3K18ac) in relation to the production of cytokines in murine splenocytes after LPS stimulation. (R)-SFN was able to modulate the inflammatory response and oxidative stress induced by LPS stimulation in murine peritoneal macrophages through the inhibition of reactive oxygen species (ROS), nitric oxide (NO) and cytokine (IL-1β, IL-6, IL-17, IL-18 and TNF-α) production by down-regulating the expression of pro-inflammatory enzymes (iNOS, COX-2 and mPGES-1). We also found that activation of the Nrf-2/HO-1 axis and inhibition of the JAK2/STAT-3, MAPK, canonical and non-canonical inflammasome signaling pathways could have been responsible for the immunomodulatory effects of (R)-SFN. Furthermore, (R)-SFN modulated epigenetic modifications through histone methylation (H3K9me3) and deacetylation (H3K18ac) in LPS-activated spleen cells. Collectively, our results suggest that (R)-SFN could be a promising epinutraceutical compound for the management of immunoinflammatory diseases.

NRF2 and Mitochondrial Function in Cancer and Cancer Stem Cells

The NRF2–KEAP1 system is a fundamental component of the cellular response that controls a great variety of transcriptional targets that are mainly involved in the regulation of redox homeostasis and multiple cytoprotective mechanisms that confer adaptation to the stress conditions. The pleiotropic response orchestrated by NRF2 is particularly relevant in the context of oncogenic activation, wherein this transcription factor acts as a key driver of tumor progression and cancer cells’ resistance to treatment. For this reason, NRF2 has emerged as a promising therapeutic target in cancer cells, stimulating extensive research aimed at the identification of natural, as well as chemical, NRF2 inhibitors. Excitingly, the influence of NRF2 on cancer cells’ biology extends far beyond its mere antioxidant function and rather encompasses a functional crosstalk with the mitochondrial network that can influence crucial aspects of mitochondrial homeostasis, including biogenesis, oxidative phosphorylation, metabolic reprogramming, and mitophagy. In the present review, we summarize the current knowledge of the reciprocal interrelation between NRF2 and mitochondria, with a focus on malignant tumors and cancer stem cells.

Sulforaphane induces lipophagy through the activation of AMPK-mTOR-ULK1 pathway signaling in adipocytes

Lipophagy, a form of selective autophagy, degrades lipid droplet (LD) in adipose tissue and the liver. The chemotherapeutic isothiocyanate sulforaphane (SFN) contributes to lipolysis through the activation of hormone-sensitive lipase and the browning of white adipocytes. However, the details concerning the regulation of lipolysis in adipocytes by SFN-mediated autophagy remain unclear. In this study, we investigated the effects of SFN on autophagy in the epididymal fat of mice fed a high-fat diet (HFD) or control-fat diet and on the molecular mechanisms of autophagy in differentiated 3T3-L1 cells. Western blotting revealed that the protein expression of lipidated LC3 (LC3-II), an autophagic substrate, was induced after 3T3-L1 adipocytes treatment with SFN. In addition, SFN increased the LC3-II protein expression in the epididymal fat of mice fed an HFD. Immunofluorescence showed that the SFN-induced LC3 expression was co-localized with LDs in 3T3-L1 adipocytes and with perilipin, the most abundant adipocyte-specific protein, in adipocytes of mice fed an HFD. Next, we confirmed that SFN activates autophagy flux in differentiated 3T3-L1 cells using the mCherry-EGFP-LC3 and GFP-LC3-RFP-LC3ΔG probe. Furthermore, we examined the induction mechanisms of autophagy by SFN in 3T3-L1 adipocytes using western blotting. ATG5 knockdown partially blocked the SFN-induced release of fatty acids from LDs in mature 3T3-L1 adipocytes. SFN time-dependently elicited the phosphorylation of AMPK, the dephosphorylation of mTOR, and the phosphorylation of ULK1 in differentiated 3T3-L1 cells. Taken together, these results suggest that SFN may provoke lipophagy through AMPK-mTOR-ULK1 pathway signaling, resulting in partial lipolysis of adipocytes.

NRF2 in dermatological disorders: Pharmacological activation for protection against cutaneous photodamage and photodermatosis

The skin barrier and its endogenous protective mechanisms cope daily with exogenous stressors, of which ultraviolet radiation (UVR) poses an imminent danger. Although the skin is able to reduce the potential damage, there is a need for comprehensive strategies for protection. This is particularly important when developing pharmacological approaches to protect against photocarcinogenesis. Activation of NRF2 has the potential to provide comprehensive and long-lasting protection due to the upregulation of numerous cytoprotective downstream effector proteins that can counteract the damaging effects of UVR. This is also applicable to photodermatosis conditions that exacerbate the damage caused by UVR. This review describes the alterations caused by UVR in normal skin and photosensitive disorders, and provides evidence to support the development of NRF2 activators as pharmacological treatments. Key natural and synthetic activators with photoprotective properties are summarized. Lastly, the gap in knowledge in research associated with photodermatosis conditions is highlighted.

A sustainable photochemical aerobic sulfide oxidation: access to sulforaphane and modafinil

Sulfoxide-containing molecules are an important class of compounds in the pharmaceutical industry and many efforts have been made to develop new and green protocols, targeting the chemoselective transformation of sulfides into sulfoxides. Photochemistry is a rapidly expanding research field employing light as the energy source. Photochemical aerobic processes possess additional advantages to photochemistry and may find applications in the chemical industries. Herein, a 370 nm catalyst-free aerobic protocol was developed, using 2-Me-THF as the green solvent. At the same time, two low-catalyst-loading anthraquinone-based processes (under a CFL lamp or 427 nm irradiation) in 2-Me-THF were developed. Furthermore, a broad range of substrates was tested. We also implemented our protocols towards the synthesis of the pharmaceutical active ingredients (APIs) sulforaphane and modafinil.

Investigating the effect of Sulforaphane on AMPK/AKT/NRF2 pathway in human granulosa-lutein cells under H2O2-induced oxidative stress

Excessive production of reactive oxygen species (ROS) in granulosa cells (GCs) plays a role in pathogenesis of polycystic ovarian syndrome (PCOS) by developing oxidative stress (OS). It was shown that Sulforaphane (SFN), with known antioxidant properties, can have protective effects in different diseases through affecting the nuclear factor (erythroid-derived 2)-like 2 (NRF2) signaling pathway. Thus, the purpose of the current work was to examine the protective impact of SFN through the activation of the AMPK/AKT/NRF2 pathway against OS produced by H2O2 in granulosa-lutein cells (GLCs). Individuals' GLCs were obtained during ovum retrieval in intracytoplasmic sperm injection (ICSI) cycles. First, the induced OS model was created in GLCs using H₂O₂ exposure. To examine the protective effect of SFN against OS, the cells were cultured for 24 h in presence or absence of SFN. Eventually, the levels of intracellular ROS and apoptosis were measured by flow cytometry, and genes and proteins expression levels of AMPK, AKT, and NRF2 were evaluated using qRT-PCR and western blotting. Compared to the control group, the levels of intracellular ROS and apoptosis rose dramatically in GLCs with enhanced OS. SFN therapy decreased ROS and apoptosis levels and increased the overexpression of AMPK, AKT, and NRF2 genes and proteins. This study's results revealed that SFN exposure results in the alleviation of ROS and apoptosis levels possibly through activating the overexpression of genes and proteins of AMPK, AKT, and NRF2, and exerts its protective effects against OS in GLCs.

Activation of the transcription factor NRF2 mediates the anti-inflammatory properties of a subset of over-the-counter and prescription NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase (COX) enzymes and are ubiquitously used for their anti-inflammatory properties. However, COX inhibition alone fails to explain numerous clinical outcomes of NSAID usage. Screening commonly used NSAIDs in primary human and murine myeloid cells demonstrated that NSAIDs could be differentiated by their ability to induce growth/differentiation factor 15 (GDF15), independent of COX specificity. Using genetic and pharmacologic approaches, NSAID-mediated GDF15 induction was dependent on the activation of nuclear factor erythroid 2-related factor 2 (NRF2) in myeloid cells. Sensing by Cysteine 151 of the NRF2 chaperone, Kelch-like ECH-associated protein 1 (KEAP1) was required for NSAID activation of NRF2 and subsequent anti-inflammatory effects both in vitro and in vivo. Myeloid-specific deletion of NRF2 abolished NSAID-mediated tissue protection in murine models of gout and endotoxemia. This highlights a noncanonical NRF2-dependent mechanism of action for the anti-inflammatory activity of a subset of commonly used NSAIDs.

Counteracting Health Risks by Modulating Homeostatic Signaling

Homeostasis was initially conceptualized by Bernard and Cannon around a century ago as a steady state of physiological parameters that vary within a certain range, such as blood pH, body temperature, and heart rate^1,2. The underlying mechanisms that maintain homeostasis are explained by negative feedbacks that are executed by the neuronal, endocrine, and immune systems. At the cellular level, homeostasis, such as that of redox and energy steady state, also exists and is regulated by various cell signaling pathways. The induction of homeostatic mechanism is critical for human to adapt to various disruptive insults (stressors); while on the other hand, adaptation occurs at the expense of other physiological processes and thus runs the risk of collateral damages, particularly under conditions of chronic stress. Conceivably, anti-stress protection can be achieved by stressor-mimicking medicinals that elicit adaptive responses prior to an insult and thereby serve as health risk countermeasures; and in situations where maladaptation may occur, downregulating medicinals could be used to suppress the responses and prevent subsequent pathogenesis. Both strategies are preemptive interventions particularly suited for individuals who carry certain lifestyle, environmental, or genetic risk factors. In this article, we will define and characterize a new modality of prophylactic intervention that forestalls diseases via modulating homeostatic signaling. Moreover, we will provide evidence from the literature that support this concept and distinguish it from other homeostasis-related interventions such as adaptogen, hormesis, and xenohormesis.

Synthesis and Evaluation of Functionalized Aryl and Biaryl Isothiocyanates Against Human MCF-7 Cells

Organic isothiocyanates (ITCs) are a class of anticancer agents which naturally result from the enzymatic degradation of glucosinolates produced by Brassica vegetables. Previous studies have demonstrated that the structure of an ITC impacts its potency and mode(s) of anticancer properties, opening the way to preparation and evaluation of synthetic, non-natural ITC analogues. This study describes the preparation of a library of 79 non-natural ITC analogues intended to probe further structure-activity relationships for aryl ITCs and second-generation, functionalized biaryl ITC variants. ITC candidates were subjected to bifurcated evaluation of antiproliferative and antioxidant response element (ARE)-induction capacity against human MCF-7 cells. The results of this study led to the identification of (1) several key structure-activity relationships and (2) lead ITCs demonstrating potent antiproliferative properties.

Exploring the role of senescence inducers and senotherapeutics as targets for anticancer natural products

During the last few decades, cancer has remained one of the deadliest diseases that endanger human health, emphasizing urgent drug discovery. Cellular senescence has gained a great deal of attention in recent years because of its link to the development of cancer therapy. Senescent cells are incapable of proliferating due to irreversibly inhibited the initiation of the cell cycle pathways. However, senescent cells aggregate in tissues and produce a pro-inflammatory secretome called senescence-associated secretory phenotype (SASP) that can cause serious harmful effects if not managed properly. There is mounting evidence that senescent cells lead to various phases of tumorigenesis in various anatomical sites, owing mostly to the paracrine activities of the SASP. Therefore, a new treatment field called senotherapeutics has been established. Senotherapeutics are newly developed anticancer agents that have been demonstrated to inhibit cancer effectively. In light of recent findings, several promising natural products have been identified as senescence inducers and senotherapeutics, including, miliusanes, epigallocatechin gallate, phloretin, silybin, resveratrol, genistein, sulforaphane, quercetin, allicin, fisetin, piperlongumine, berberine, triptolide, tocotrienols and curcumin analogs. Several of them have already been validated through preclinical trials and exert an enormous potential for clinical trials. This review article focuses on and summarises the latest advances on cellular senescence and its potential as a target for cancer treatment and highlights the well-known natural products as senotherapeutics for cancer treatment.

Sulfur compounds: From plants to humans and their role in chronic disease prevention

Sulfur is essential for the health of plants and is an indispensable dietary component for human health and disease prevention. Its incorporation into our food supply is heavily reliant upon the uptake of sulfur into plant tissue and our subsequent intake. Dietary requirements for sulfur are largely calculated based upon requirements for the sulfur-containing amino acids (SAA), cysteine and methionine, to meet the demands for synthesis of proteins, enzymes, co-enzymes, vitamins, and hormones. SAA are found in abundance in animal sources and are relatively low in plants. However, some plants, particularly cruciferous and allium vegetables, produce many protective sulfur-containing secondary metabolites, such as glucosinolates and cysteine sulfoxides. The variety and quantity of these sulfur-containing metabolites are extensive and their effects on human health are wide-reaching. Many benefits appear to be related to sulfur's role in redox biochemistry, protecting against uncontrolled oxidative stress and inflammation; features consistent within cardiometabolic dysfunction and many chronic metabolic diseases of aging. This narrative explores the origins and importance of sulfur, its incorporation into our food supply and dietary sources. It also explores the overarching potential of sulfur for human health, particularly around the amelioration of oxidative stress and chronic inflammation, and subsequent chronic disease prevention.

Sulforaphane activates anti-inflammatory microglia, modulating stress resilience associated with BDNF transcription

Sulforaphane (SFN) is an organic isothiocyanate and an NF-E2-related factor-2 (Nrf2) inducer that exerts prophylactic effects on depression-like behavior in mice. However, the underlying mechanisms remain poorly understood. Brain-derived neurotrophic factor (BDNF), a neurotrophin, is widely accepted for its antidepressant effects and role in stress resilience. Here, we show that SFN confers stress resilience via BDNF upregulation and changes in abnormal dendritic spine morphology in stressed mice, which is accompanied by rectifying the irregular levels of inflammatory cytokines. Mechanistic studies demonstrated that SFN activated Nrf2 to promote BDNF transcription by binding to the exon I promoter, which is associated with increased Nrf2, and decreased methyl-CpG binding protein-2 (MeCP2), a transcriptional suppressor of BDNF, in BV2 microglial cells. Furthermore, SFN inhibited the pro-inflammatory phenotype and activated the anti-inflammatory phenotype of microglia, which was associated with increased Nrf2 and decreased MeCP2 expression in microglia of stressed mice. Hence, our findings support that Nrf2 induces BDNF transcription via upregulation of Nrf2 and downregulation of MeCP2 in microglia, which is associated with changes in the morphology of damaged dendritic spines in stressed mice. Meanwhile, the data presented here provide evidence for the application of SFN as a candidate for the prevention and intervention of depression.

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.

Membrane Vesicles for Nanoencapsulated Sulforaphane Increased Their Anti-Inflammatory Role on an In Vitro Human Macrophage Model

At present, there is a growing interest in finding new non-toxic anti-inflammatory drugs to treat inflammation, which is a key pathology in the development of several diseases with considerable mortality. Sulforaphane (SFN), a bioactive compound derived from Brassica plants, was shown to be promising due to its anti-inflammatory properties and great potential, though its actual clinical use is limited due to its poor stability and bioavailability. In this sense, the use of nanocarriers could solve stability-related problems. In the current study, sulforaphane loaded into membrane vesicles derived from broccoli plants was studied to determine the anti-inflammatory potential in a human-macrophage-like in vitro cell model under both normal and inflammatory conditions. On the one hand, the release of SFN from membrane vesicles was modeled in vitro, and two release phases were stabilized, one faster and the other slower due to the interaction between SFN and membrane proteins, such as aquaporins. Furthermore, the anti-inflammatory action of sulforaphane-loaded membrane vesicles was demonstrated, as a decrease in interleukins crucial for the development of inflammation, such as TNF-α, IL-1β and IL-6, was observed. Furthermore, these results also showed that membrane vesicles by themselves had anti-inflammatory properties, opening the possibility of new lines of research to study these vesicles, not only as carriers but also as active compounds.

The role of diet in renal cell carcinoma incidence: an umbrella review of meta-analyses of observational studies

BACKGROUND

Evidence associating diet with the incidence of renal cell carcinoma (RCC) is inconclusive. We aimed to summarize evidence associating dietary factors with RCC incidence and assess the strength and validity of this evidence.

METHODS

We conducted an umbrella review of systematic reviews or meta-analyses (SRoMAs) that assessed the association between diet and RCC incidence. Through April 2021, PubMed, Web of Science, Embase, The Cochrane Library, Scopus, and WCRF were searched. Two independent reviewers selected studies, extracted data, and appraised the quality of SRoMAs. According to credibility assessment criteria, evidence can be divided into five categories: convincing (class I), highly suggestive (class II), suggestive (class III), weak (class IV), and nonsignificant (class V).

RESULTS

Twenty-nine meta-analyses were obtained after screening. After excluding 7 overlapping meta-analyses, 22 meta-analyses including 502 individual studies and 64 summary hazard ratios for RCC incidence were included: dietary patterns or dietary quality indices (n = 6), foods (n = 13), beverages (n = 4), alcohol (n = 7), macronutrients (n =15), and micronutrients (n =19). No meta-analyses had high methodological quality. Five meta-analyses exhibited small study effects; one meta-analysis showed evidence of excess significance bias. No dietary factors showed convincing or highly suggestive evidence of association with RCC in the overall analysis. Two protective factors had suggestive evidence (vegetables (0.74, 95% confidence interval 0.63 to 0.86) and vitamin C (0.77, 0.66 to 0.90)) in overall analysis. One protective factor had convincing evidence (moderate drinking (0.77, 0.70 to 0.84)) in Europe and North America and one protective factor had highly suggestive evidence (cruciferous vegetables (0.78, 0.70 to 0.86)) in North America.

CONCLUSIONS

Although many meta-analyses have assessed associations between dietary factors and RCC, no high-quality evidence exists (classes I and II) in the overall analysis. Increased intake of vegetables and vitamin C is negatively associated with RCC risk. Moderate drinking might be beneficial for Europeans and North Americans, and cruciferous vegetables might be beneficial to North Americans, but the results should be interpreted with caution. More researches are needed in the future.

TRIAL REGISTRATION

PROSPERO CRD42021246619.

Glucoraphanin Increases Intracellular Hydrogen Sulfide (H2S) Levels and Stimulates Osteogenic Differentiation in Human Mesenchymal Stromal Cell

Osteopenia and osteoporosis are among the most prevalent consequences of ageing, urging the promotion of healthy nutritional habits as a tool in preventing bone fractures. Glucosinolates (GLSs) are organosulfur compounds considered relatively inert precursors of reactive derivatives isothiocyanates (ITCs). Recent evidence suggests that GLSs may exert biological properties based on their capacity to release hydrogen sulfide (H₂S). H₂S-donors are known to exert anabolic function on bone cells. Here, we investigated whether a GLS, glucoraphanin (GRA) obtained from Tuscan black kale, promotes osteogenesis in human mesenchymal stromal cells (hMSCs). H₂S release in buffer and intracellular H₂S levels were detected by amperometric measurements and fluorimetric/cytofluorimetric analyses, respectively. Alizarin red staining assay and real-time PCR were performed to evaluate mineral apposition and mRNA expression of osteogenic genes. Using an in vitro cell culture model, our data demonstrate a sulforaphane (SFN)-independent osteogenic stimulation of GRA in hMSCs, at least partially attributable to H₂S release. In particular, GRA upregulated the expression of osteogenic genes and enhanced mineral apposition while increasing intracellular concentrations of H₂S. Overall, this study suggests the feasibility of using cruciferous derivatives as natural alternatives to chemical H₂S-donors as adjuvant therapies in the treatment of bone-wasting diseases.

Role for Plant-Derived Antioxidants in Attenuating Cancer Cachexia

Cancer cachexia is the progressive muscle wasting and weakness experienced by many cancer patients. It can compromise the response to gold standard cancer therapies, impair functional capacity and reduce overall quality of life. Cancer cachexia accounts for nearly one-third of all cancer-related deaths and has no effective treatment. The pathogenesis of cancer cachexia and its progression is multifactorial and includes increased oxidative stress derived from both the tumor and the host immune response. Antioxidants have therapeutic potential to attenuate cancer-related muscle loss, with polyphenols, a group of plant-derived antioxidants, being the most widely investigated. This review describes the potential of these plant-derived antioxidants for treating cancer cachexia.

Enzyme systems involved in glucosinolate metabolism in Companilactobacillus farciminis KB1089

Cruciferous vegetables are rich sources of glucosinolates (GSLs). GSLs are degraded into isothiocyanates, which are potent anticarcinogens, by human gut bacteria. However, the mechanisms and enzymes involved in gut bacteria-mediated GSL metabolism are currently unclear. This study aimed to elucidate the enzymes involved in GSL metabolism in lactic acid bacteria, a type of gut bacteria. Companilactobacillus farciminis KB1089 was selected as a lactic acid bacteria strain model that metabolizes sinigrin, which is a GSL, into allylisothiocyanate. The sinigrin-metabolizing activity of this strain is induced under glucose-absent and sinigrin-present conditions. A quantitative comparative proteomic analysis was conducted and a total of 20 proteins that were specifically expressed in the induced cells were identified. Three candidate proteins, β-glucoside-specific IIB, IIC, IIA phosphotransferase system (PTS) components (CfPttS), 6-phospho-β-glucosidase (CfPbgS) and a hypothetical protein (CfNukS), were suspected to be involved in sinigrin-metabolism and were thus investigated further. We hypothesize a pathway for sinigrin degradation, wherein sinigrin is taken up and phosphorylated by CfPttS, and subsequently, the phosphorylated entity is degraded by CfPbgS. As expression of both pttS and pbgS genes clearly gave Escherichia coli host strain sinigrin converting activity, these genes were suggested to be responsible for sinigrin degradation. Furthermore, heterologous expression analysis using Lactococcus lactis suggested that CfPttS was important for sinigrin degradation and CfPbgS degraded phosphorylated sinigrin.

Sulforaphane enhances the antitumor response of chimeric antigen receptor T cells by regulating PD-1/PD-L1 pathway

BACKGROUND

Chimeric antigen receptor T (CAR-T) cell therapy has limited effects in the treatment of solid tumors. Sulforaphane (SFN) is known to play an important role in inhibiting tumor growth, but its effect on CAR-T cells remains unclear. The goal of the current study was to determine whether combined CAR-T cells and SFN could provide antitumor efficacy against solid tumors.

METHODS

The effect of combined SFN and CAR-T cells was determined in vitro using a co-culture system and in vivo using a xenograft mouse model. We further validated the effects of combination therapy in patients with cancer.

RESULTS

In vitro, the combination of SFN and CAR-T cells resulted in enhanced cytotoxicity and increased lysis of tumor cells. We found that SFN suppressed programmed cell death 1 (PD-1) expression in CAR-T cells and potentiated antitumor functions in vitro and in vivo. As a ligand of PD-1, programmed cell death ligand 1 (PD-L1) expression was also decreased in tumor cells after SFN treatment. In addition, β-TrCP was increased by SFN, resulting in higher activation of ubiquitination-mediated proteolysis of PD-L1, which induced PD-L1 degradation. The combination of SFN and CAR-T cell therapy acted synergistically to promote better immune responses in vivo compared with monotherapy. In clinical treatments, PD-1 expression was lower, and proinflammatory cytokine levels were higher in patients with various cancers who received CAR-T cells and took SFN orally than that in the control group.

CONCLUSION

SFN improves the cytotoxicity of CAR-T cells by modulating the PD-1/PD-L1 pathway, which may provide a promising strategy for the combination of SFN with CAR-T cells for cancer immunotherapy.

Emerging agents that target signaling pathways to eradicate colorectal cancer stem cells

Colorectal cancer (CRC) represents the third most commonly diagnosed cancer and the second leading cause of cancer death worldwide. The modern concept of cancer biology indicates that cancer is formed of a small population of cells called cancer stem cells (CSCs), which present both pluripotency and self-renewal properties. These cells are considered responsible for the progression of the disease, recurrence and tumor resistance. Interestingly, some cell signaling pathways participate in CRC survival, proliferation, and self-renewal properties, and most of them are dysregulated in CSCs, including the Wingless (Wnt)/β-catenin, Notch, Hedgehog, nuclear factor kappa B (NF-κB), Janus kinase/signal transducer and activator of transcription (JAK/STAT), peroxisome proliferator-activated receptor (PPAR), phosphatidyl-inositol-3-kinase/Akt/mechanistic target of rapamycin (PI3K/Akt/mTOR), and transforming growth factor-β (TGF-β)/Smad pathways. In this review, we summarize the strategies for eradicating CRC stem cells by modulating these dysregulated pathways, which will contribute to the study of potential therapeutic schemes, combining conventional drugs with CSC-targeting drugs, and allowing better cure rates in anti-CRC therapy.

The Antioxidant Transcription Factor Nrf2 in Cardiac Ischemia-Reperfusion Injury

Nuclear factor erythroid-2 related factor 2 (Nrf2) is a transcription factor that controls cellular defense responses against toxic and oxidative stress by modulating the expression of genes involved in antioxidant response and drug detoxification. In addition to maintaining redox homeostasis, Nrf2 is also involved in various cellular processes including metabolism and inflammation. Nrf2 activity is tightly regulated at the transcriptional, post-transcriptional and post-translational levels, which allows cells to quickly respond to pathological stress. In the present review, we describe the molecular mechanisms underlying the transcriptional regulation of Nrf2. We also focus on the impact of Nrf2 in cardiac ischemia-reperfusion injury, a condition that stimulates the overproduction of reactive oxygen species. Finally, we analyze the protective effect of several natural and synthetic compounds that induce Nrf2 activation and protect against ischemia-reperfusion injury in the heart and other organs, and their potential clinical application.

Sulforaphane Causes Cell Cycle Arrest and Apoptosis in Human Glioblastoma U87MG and U373MG Cell Lines under Hypoxic Conditions

Glioblastoma multiforme (GBM) is the most prevalent and aggressive primary brain tumor. The median survival rate from diagnosis ranges from 15 to 17 months because the tumor is resistant to most therapeutic strategies. GBM exhibits microvascular hyperplasia and pronounced necrosis triggered by hypoxia. Sulforaphane (SFN), an isothiocyanate derived from cruciferous vegetables, has already demonstrated the ability to inhibit cell proliferation, by provoking cell cycle arrest, and leading to apoptosis in many cell lines. In this study, we investigated the antineoplastic effects of SFN [20-80 μM for 48 h] in GBM cells under normoxic and hypoxic conditions. Cell viability assays, flow cytometry, and Western blot results revealed that SFN could induce apoptosis of GBM cells in a dose-dependent manner, under both conditions. In particular, SFN significantly induced caspase 3/7 activation and DNA fragmentation. Moreover, our results demonstrated that SFN suppressed GBM cells proliferation by arresting the cell cycle at the S-phase, also under hypoxic condition, and that these effects may be due in part to its ability to induce oxidative stress by reducing glutathione levels and to increase the phosphorylation of extracellular signal-regulated kinases (ERKs). Overall, we hypothesized that SFN treatment might serve as a potential therapeutic strategy, alone or in combination, against GBM.

Impaired antioxidant KEAP1-NRF2 system in amyotrophic lateral sclerosis: NRF2 activation as a potential therapeutic strategy

BACKGROUND

Oxidative stress (OS) is an imbalance between oxidant and antioxidant species and, together with other numerous pathological mechanisms, leads to the degeneration and death of motor neurons (MNs) in amyotrophic lateral sclerosis (ALS).

MAIN BODY

Two of the main players in the molecular and cellular response to OS are NRF2, the transcription nuclear factor erythroid 2-related factor 2, and its principal negative regulator, KEAP1, Kelch-like ECH (erythroid cell-derived protein with CNC homology)-associated protein 1. Here we first provide an overview of the structural organization, regulation, and critical role of the KEAP1-NRF2 system in counteracting OS, with a focus on its alteration in ALS. We then examine several compounds capable of promoting NRF2 activity thereby inducing cytoprotective effects, and which are currently in different stages of clinical development for many pathologies, including neurodegenerative diseases.

CONCLUSIONS

Although challenges associated with some of these compounds remain, important advances have been made in the development of safer and more effective drugs that could actually represent a breakthrough for fatal degenerative diseases such as ALS.

Metabolic Fate of Dietary Glucosinolates and Their Metabolites: A Role for the Microbiome

Robust evidence shows that phytochemicals from cruciferous vegetables, like broccoli, are associated with numerous health benefits. The anti-cancer properties of these foods are attributed to bioactive isothiocyanates (ITCs) and indoles, phytochemicals generated from biological precursor compounds called glucosinolates. ITCs, and particularly sulforaphane (SFN), are of intense interest as they block the initiation, and suppress the progression of cancer, through genetic and epigenetic mechanisms. The efficacy of these compounds is well-demonstrated in cell culture and animal models, however, high levels of inter-individual variation in absorption and excretion of ITCs is a significant barrier to the use of dietary glucosinolates to prevent and treat disease. The source of inter-individual ITC variation has yet to be fully elucidated and the gut microbiome may play a key role. This review highlights evidence that the gut microbiome influences the metabolic fate and activity of ITCs. Human feeding trials have shown inter-individual variations in gut microbiome composition coincides with variations in ITC absorption and excretion, and some bacteria produce ITCs from glucosinolates. Additionally, consumption of cruciferous vegetables can alter the composition of the gut microbiome and shift the physiochemical environment of the gut lumen, influencing the production of phytochemicals. Microbiome and diet induced changes to ITC metabolism may lead to the decrease of cancer fighting phytochemicals such as SFN and increase the production of biologically inert ones like SFN-nitrile. We conclude by offering perspective on the use of novel “omics” technologies to elucidate the interplay of the gut microbiome and ITC formation.