Allyl Isothiocyanate Induces Cell Toxicity by Multiple Pathways in Human Breast Cancer Cells

Transient Receptor Potential Ankyrin 1 Ion Channel Is Expressed in Osteosarcoma and Its Activation Reduces Viability

Osteosarcoma is a highly malignant, painful cancer with poor treatment opportunities and a bad prognosis. Transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) receptors are non-selective cation channels that have been of great interest in cancer, as their expression is increased in some malignancies. In our study we aim to characterize the expression and functionality of the TRPA1 and TRPV1 channels in human and mouse osteosarcoma tissues and in a mouse cell line. TRPA1/Trpa1 and TRPV1/Trpv1 mRNA expressions were demonstrated by PCR gel electrophoresis and RNAscope in situ hybridization. The function of these channels was confirmed by their radioactive 45Ca2+ uptake in response to the TRPA1 agonist, Allyl-isothiocyanate (AITC), and TRPV1 agonist, capsaicin, in K7M2 cells. An ATP-based K2M7 cell viability luminescence assay was used to determine cell viability after AITC or capsaicin treatments. Both TRPA1/Trpa1 and TRPV1/Trpv1 were expressed similarly in human and mouse osteosarcoma tissues, while Trpa1 transcripts were more abundantly present in K7M2 cells. TRPA1 activation with 200 µM AITC induced a significant 45Ca2+ influx into K7M2 cells, and the antagonist attenuated this effect. In accordance with the lower Trpv1 expression, capsaicin induced a moderate 45Ca2+ uptake, which did not reach the level of statistical significance. Both AITC and capsaicin significantly reduced K7M2 cell viability, demonstrating EC50 values of 22 µM and 74 µM. The viability-decreasing effect of AITC was significantly but only partially antagonized by HC-030031, but the action of capsaicin was not affected by the TRPV1 antagonist capsazepine. We provide here the first data on the functional expression of the TRPA1 and TRPV1 ion channels in osteosarcoma, suggesting novel diagnostic and/or therapeutic perspectives.

Allyl isothiocyanate regulates oxidative stress, inflammation, cell proliferation, cell cycle arrest, apoptosis, angiogenesis, invasion and metastasis via interaction with multiple cell signaling pathways

Cancer growth is a molecular mechanism initiated by genetic and epigenetic modifications that are involved in cell proliferation, differentiation, apoptosis, and senescence pathways. Chemoprevention is an important strategy for cancer treatment that leads to blocking, reversing, or impeding the multistep process of tumorigenesis, including the blockage of its vital morphogenetic milestones viz. normal, preneoplasia, neoplasia, and metastasis. Naturally occurring phytochemicals are becoming ever more popular compared to synthetic drugs for many reasons, including safety, bioavailability, efficacy, and easy availability. Allyl isothiocyanate (AITC) is a natural compound present in all plants of the Cruciferae family, such as Brussels sprouts, cauliflower, mustard, cabbage, kale, horseradish, and wasabi. In vitro and in vivo studies carried out over the decades have revealed that AITC inhibits tumorigenesis without any toxicity and undesirable side effects. The bioavailability of AITC is exceedingly high, as it was reported that nearly 90% of orally administered AITC is absorbed. AITC exhibits multiple pharmacological properties among which its anticancer activity is the most significant for cancer treatment. Its anticancer activity is exerted via selective modulation of multiple cell signaling pathways related to oxidative stress, inflammation, cell proliferation, cell cycle arrest, apoptosis, angiogenesis, invasion, and metastasis. This review highlights the current knowledge on molecular targets that are involved in the anticancer effect of AITC associated with (i) inhibition of carcinogenic activation and induction of antioxidants, (ii) suppression of pro-inflammatory and cell proliferative signals, (iii) induction of cell cycle arrest and apoptosis, and (iv) inhibition of angiogenic and invasive signals related to metastasis.

Allyl-isothiocyanate against colorectal cancer via the mutual dependent regulation of p21 and Nrf2

Allyl-isothiocyanate (AITC) is a common Isothiocyanates (ITC) and its chemo-preventive and anti-tumor effects are believed to be related to the activation of NF-E2 p45-related Factor 2 (Nrf2). However, its anti-tumor effects on colorectal cancer (CRC) are not well elucidated. Here, we investigated the therapeutic in vitro and/or in vivo effects and mechanisms of action (MOA) for AITC on CRC cell line HCT116 (human) and MC38 (mouse). AITC treatment in a low concentration range (1 mg/kg in vivo) significantly inhibited the tumor cell growth and increased the expression of p21 and Nrf2. The AITC-mediated induction of p21 was dependent on Nrf2 but independent on p53 in vitro and in vivo at low dose. In contrast, the high dose of AITC (5 mg/kg in vivo) failed to increase substantial levels of p21/MdmX, and impaired the total antioxidant capacity of tumors and subsequent anti-tumor effect in vivo. These results suggest that an optimal dose of AITC is important and required for the proper Nrf2 activation and its anti-CRC effects and thus, providing insights into the potential applications of AITC for the prevention and treatment of CRC.

Allyl Isothiocyanate Suppresses the Proliferation in Oral Squamous Cell Carcinoma via Mediating the KDM8/CCNA1 Axis

The dysregulated expression of cyclin genes can lead to the uncontrolled proliferation of cancer cells. Histone demethylase Jumonji-C domain-containing protein 5 (KDM8, JMJD5) and cyclin A1 (CCNA1) are pivotal in cell cycle progression. A promising candidate for augmenting cancer treatment is Allyl isothiocyanate (AITC), a natural dietary chemotherapeutic and epigenetic modulator. This study aimed to investigate AITC's impact on the KDM8/CCNA1 axis to elucidate its role in oral squamous cell carcinoma (OSCC) tumorigenesis. The expression of KDM8 and CCNA1 was assessed using a tissue microarray (TMA) immunohistochemistry (IHC) assay. In vitro experiments with OSCC cell lines and in vivo experiments with patient-derived tumor xenograft (PDTX) and SAS subcutaneous xenograft tumor models were conducted to explore AITC's effects on their expression and cell proliferation. The results showed elevated KDM8 and CCNA1 levels in the OSCC patient samples. AITC exhibited inhibitory effects on OSCC tumor growth in vitro and in vivo. Additionally, AITC downregulated KDM8 and CCNA1 expression while inducing histone H3K36me2 expression in oral cancer cells. These findings underscore AITC's remarkable anticancer properties against oral cancer, highlighting its potential as a therapeutic option for oral cancer treatment by disrupting the cell cycle by targeting the KDM8/CCNA1 axis.

Allyl Isothiocianate Induces Ca2+ Signals and Nitric Oxide Release by Inducing Reactive Oxygen Species Production in the Human Cerebrovascular Endothelial Cell Line hCMEC/D3

Nitric oxide (NO) represents a crucial mediator to regulate cerebral blood flow (CBF) in the human brain both under basal conditions and in response to somatosensory stimulation. An increase in intracellular Ca2+ concentrations ([Ca2+]i) stimulates the endothelial NO synthase to produce NO in human cerebrovascular endothelial cells. Therefore, targeting the endothelial ion channel machinery could represent a promising strategy to rescue endothelial NO signalling in traumatic brain injury and neurodegenerative disorders. Allyl isothiocyanate (AITC), a major active constituent of cruciferous vegetables, was found to increase CBF in non-human preclinical models, but it is still unknown whether it stimulates NO release in human brain capillary endothelial cells. In the present investigation, we showed that AITC evoked a Ca2+-dependent NO release in the human cerebrovascular endothelial cell line, hCMEC/D3. The Ca2+ response to AITC was shaped by both intra- and extracellular Ca2+ sources, although it was insensitive to the pharmacological blockade of transient receptor potential ankyrin 1, which is regarded to be among the main molecular targets of AITC. In accord, AITC failed to induce transmembrane currents or to elicit membrane hyperpolarization, although NS309, a selective opener of the small- and intermediate-conductance Ca2+-activated K+ channels, induced a significant membrane hyperpolarization. The AITC-evoked Ca2+ signal was triggered by the production of cytosolic, but not mitochondrial, reactive oxygen species (ROS), and was supported by store-operated Ca2+ entry (SOCE). Conversely, the Ca2+ response to AITC did not require Ca2+ mobilization from the endoplasmic reticulum, lysosomes or mitochondria. However, pharmacological manipulation revealed that AITC-dependent ROS generation inhibited plasma membrane Ca2+-ATPase (PMCA) activity, thereby attenuating Ca2+ removal across the plasma membrane and resulting in a sustained increase in [Ca2+]i. In accord, the AITC-evoked NO release was driven by ROS generation and required ROS-dependent inhibition of PMCA activity. These data suggest that AITC could be exploited to restore NO signalling and restore CBF in brain disorders that feature neurovascular dysfunction.

Promising Strategy of mPTP Modulation in Cancer Therapy: An Emerging Progress and Future Insight

Cancer has been progressively a major global health concern. With this developing global concern, cancer determent is one of the most significant public health challenges of this era. To date, the scientific community undoubtedly highlights mitochondrial dysfunction as a hallmark of cancer cells. Permeabilization of the mitochondrial membranes has been implicated as the most considerable footprint in apoptosis-mediated cancer cell death. Under the condition of mitochondrial calcium overload, exclusively mediated by oxidative stress, an opening of a nonspecific channel with a well-defined diameter in mitochondrial membrane allows free exchange between the mitochondrial matrix and the extra mitochondrial cytosol of solutes and proteins up to 1.5 kDa. Such a channel/nonspecific pore is recognized as the mitochondrial permeability transition pore (mPTP). mPTP has been established for regulating apoptosis-mediated cancer cell death. It has been evident that mPTP is critically linked with the glycolytic enzyme hexokinase II to defend cellular death and reduce cytochrome c release. However, elevated mitochondrial Ca2+ loading, oxidative stress, and mitochondrial depolarization are critical factors leading to mPTP opening/activation. Although the exact mechanism underlying mPTP-mediated cell death remains elusive, mPTP-mediated apoptosis machinery has been considered as an important clamp and plays a critical role in the pathogenesis of several types of cancers. In this review, we focus on structure and regulation of the mPTP complex-mediated apoptosis mechanisms and follow with a comprehensive discussion addressing the development of novel mPTP-targeting drugs/molecules in cancer treatment.

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.

Allyl Isothiocyanate (AITC) Induces Apoptotic Cell Death In Vitro and Exhibits Anti-Tumor Activity in a Human Glioblastoma GBM8401/luc2 Model

Some clinically used anti-cancer drugs are obtained from natural products. Allyl isothiocyanate (AITC), a plant-derived compound abundant in cruciferous vegetables, has been shown to possess an anti-cancer ability in human cancer cell lines in vitro, including human brain glioma cells. However, the anti-cancer effects of AITC in human glioblastoma (GBM) cells in vivo have not yet been examined. In the present study, we used GBM8401/luc2 human glioblastoma cells and a GBM8401/luc2-cell-bearing animal model to identify the treatment efficacy of AITC. Here, we confirm that AITC reduced total cell viability and induced cell apoptosis in GBM8401/luc2 cells in vitro. Furthermore, Western blotting also showed that AITC induced apoptotic cell death through decreased the anti-apoptotic protein BCL-2, MCL-1 expression, increased the pro-apoptotic protein BAX expression, and promoted the activities of caspase-3, -8, and -9. Therefore, we further investigated the anti-tumor effects of AITC on human GBM8401/luc2 cell xenograft mice. The human glioblastoma GBM8401/luc2 cancer cells were subcutaneously injected into the right flank of BALB/c nude mice to generate glioblastoma xenograft mice. The animals were randomly divided into three groups: group I was treated without AITC (control); group II with 0.1 mg/day of AITC; and group III with 0.2 mg/day of AITC every 3 days for 27 days. Bodyweight, and tumor volume (size) were recorded every 3 days. Tumors exhibiting Luc2 intensity were measured, and we quantified intensity using Living Image software on days 0, 12, and 24. After treatment, tumor weight from each mouse was recorded. Tumor tissues were examined for histopathological changes using H&E staining, and we analyzed the protein levels via immunohistochemical analysis. Our results indicate that AITC significantly inhibited tumor growth at both doses of AITC due to the reduction in tumor size and weight. H&E histopathology analysis of heart, liver, spleen, and kidney samples revealed that AITC did not significantly induce toxicity. Body weight did not show significant changes in any experiment group. AITC significantly downregulated the protein expression levels of MCL-1, XIAP, MMP-9, and VEGF; however, it increased apoptosis-associated proteins, such as cleaved caspase-3, -8, and -9, in the tumor tissues compared with the control group. Based on these observations, AITC exhibits potent anti-cancer activity in the human glioblastoma cell xenograft model via inhibiting tumor cell proliferation and the induction of cell apoptosis. AITC may be a potential anti-GBM cancer drug that could be used in the future.

Extracts of Common Vegetables Inhibit the Growth of Ovary Cancer Cells

There is recent interest in a diet that can be recommended for patients suffering from cancer. In this respect, the effects were studied of the extracts of several common fruits, herbs and vegetables on the viability of two human ovary cancer cell lines (SKOV-3 and PEO1) in vitro. Normal human MRC-5 fibroblasts were used as a control cell line. The extracts of garlic, horseradish and curly kale as well as green and black tea were the most effective in lowering the viability of ovarian cancer cells, while not affecting the viability of MRC-5 fibroblasts. Except for garlic and horseradish, the cytotoxic effects of the extracts correlated with their polyphenol content. The examination of changes in the content of ATP and glutathione, in the level of reactive oxygen species, mitochondrial potential and mitochondrial mass did not show a consistent pattern, suggesting that various extracts may act via different mechanisms. Although the extracts’ toxicity to cells in vitro is a first and direct suggestion concerning their possible anticancer effects in vivo, these results point to potential vegetable candidates to become diet components recommended for ovary cancer patients.

Assessment of Methodological Pipelines for the Determination of Isothiocyanates Derived from Natural Sources

Isothiocyanates are biologically active secondary metabolites liberated via enzymatic hydrolysis of their sulfur enriched precursors, glucosinolates, upon tissue plant disruption. The importance of this class of compounds lies in their capacity to induce anti-cancer, anti-microbial, anti-inflammatory, neuroprotective, and other bioactive properties. As such, their isolation from natural sources is of utmost importance. In this review article, an extensive examination of the various parameters (hydrolysis, extraction, and quantification) affecting the isolation of isothiocyanates from naturally-derived sources is presented. Overall, the effective isolation/extraction and quantification of isothiocyanate is strongly associated with their chemical and physicochemical properties, such as polarity-solubility as well as thermal and acidic stability. Furthermore, the successful activation of myrosinase appears to be a major factor affecting the conversion of glucosinolates into active isothiocyanates.

Plant pathogenic bacterium can rapidly evolve tolerance to an antimicrobial plant allelochemical

Crop losses to plant pathogens are a growing threat to global food security and more effective control strategies are urgently required. Biofumigation, an agricultural technique where Brassica plant tissues are mulched into soils to release antimicrobial plant allelochemicals called isothiocyanates (ITCs), has been proposed as an environmentally friendly alternative to agrochemicals. Whilst biofumigation has been shown to suppress a range of plant pathogens, its effects on plant pathogenic bacteria remain largely unexplored. Here, we used a laboratory model system to compare the efficacy of different types of ITCs against Ralstonia solanacearum plant bacterial pathogen. Additionally, we evaluated the potential for ITC‐tolerance evolution under high, intermediate, and low transfer frequency ITC exposure treatments. We found that allyl‐ITC was the most efficient compound at suppressing R. solanacearum growth, and its efficacy was not improved when combined with other types of ITCs. Despite consistent pathogen growth suppression, ITC tolerance evolution was observed in the low transfer frequency exposure treatment, leading to cross‐tolerance to ampicillin beta‐lactam antibiotic. Mechanistically, tolerance was linked to insertion sequence movement at four positions in genes that were potentially associated with stress responses (H‐NS histone like protein), cell growth and competitiveness (acyltransferase), iron storage ([2‐Fe‐2S]‐binding protein) and calcium ion sequestration (calcium‐binding protein). Interestingly, pathogen adaptation to the growth media also indirectly selected for increased ITC tolerance through potential adaptations linked with metabolism and antibiotic resistance (dehydrogenase‐like protein) and transmembrane protein movement (Tat pathway signal protein). Together, our results suggest that R. solanacearum can rapidly evolve tolerance to allyl‐ITC plant allelochemical which could constrain the long‐term efficiency of biofumigation biocontrol and potentially shape pathogen evolution with plants.

Functional Transient Receptor Potential Ankyrin 1 and Vanilloid 1 Ion Channels Are Overexpressed in Human Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a common cancer with poor prognosis. Transient Receptor Potential Ankyrin 1 (TRPA1) and Vanilloid 1 (TRPV1) receptors are non-selective cation channels expressed on primary sensory neurons and epithelial and immune cells. TRPV1 mRNA and immunopositivity, as well as TRPA1-like immunoreactivity upregulation, were demonstrated in OSCC, but selectivity problems with the antibodies still raise questions and their functional relevance is unclear. Therefore, here, we investigated TRPA1 and TRPV1 expressions in OSCC and analyzed their functions. TRPA1 and TRPV1 mRNA were determined by RNAscope in situ hybridization and qPCR. Radioactive ₄₅Ca²⁺ uptake and ATP-based luminescence indicating cell viability were measured in PE/CA-PJ41 cells in response to the TRPA1 agonist allyl-isothiocyanate (AITC) and TRPV1 agonist capsaicin to determine receptor function. Both TRPA1 and TRPV1 mRNA are expressed in the squamous epithelium of the human oral mucosa and in PE/CA-PJ41 cells, and their expressions are significantly upregulated in OSCC compared to healthy mucosa. TRPA1 and TRPV1 activation (100 µM AITC, 100 nM capsaicin) induced ₄₅Ca²⁺-influx into PE/CA-PJ41 cells. Both AITC (10 nM-5 µM) and capsaicin (100 nM-45 µM) reduced cell viability, reaching significant decrease at 100 nM AITC and 45 µM capsaicin. We provide the first evidence for the presence of non-neuronal TRPA1 receptor in the OSCC and confirm the expression of TRPV1 channel. These channels are functionally active and might regulate cancer cell viability.

Anticancer effect of Selenium/Chitosan/Polyethylene glycol/Allyl isothiocyanate nanocomposites against diethylnitrosamine-induced liver cancer in rats

Background

Nano-based drug delivery systems have shown several advantages in cancer treatment like specific targeting of cancer cells, good pharmacokinetics, and lesser adverse effects. Liver cancer is a fifth most common cancer and third leading cause of cancer-related mortalities worldwide.

Objective

The present study focusses to formulate the selenium (S)/chitosan (C)/polyethylene glycol (Pg)/allyl isothiocyanate (AI) nanocomposites (SCPg-AI-NCs) and assess its therapeutic properties against the diethylnitrosamine (DEN)-induced liver cancer in rats via inhibition of oxidative stress and tumor markers.

Methodology

The SCPg-AI-NCs were synthesized by ionic gelation technique and characterized by various characterization techniques. The liver cancer was induced to the rats by injecting a DEN (200 mg/kg) on the 8th day of experiment. Then DEN-induced rats treated with 10 mg/kg of formulated SCPg-AI-NCs an hour before DEN administration for 16 weeks. The 8-hydroxy-2′ -deoxyguanosine (8-OHdG) content, albumin, globulin, and total protein were examined by standard methods. The level of glutathione (GSH), vitamin-C & -E, and superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) activities were examined using assay kits. The liver marker enzymes i.e., alanine transaminase (ALT), aspartate tansaminase (AST), γ-glutamyl transaminase (GGT), lactate dehydrogenase (LDH), and alkaline phosphatase (ALP) activities, alpha fetoprotein (AFP) and carcinoembryonic antigen (CEA), Bax, and Bcl-2 levels, and caspase-3&9 activities was examined using assay kits and the liver histopathology was assessed microscopically by hematoxylin and eosin staining method. The effect of formulated SCPg-AI-NCs on the viability and apoptotic cell death on the HepG2 cells were examined using MTT and dual staining assays, respectively.

Results

The results of different characterization studies demonstrated the formation of SCPg-AI-NCs with tetragonal shape, narrowed distribution, and size ranging from 390 to 450 nm. The formulated SCPg-AI-NCs treated liver cancer rats indicated the reduced levels of 8-OHdG, albumin, globulin, and total protein. The SCPg-AI-NCs treatment appreciably improved the GSH, vitamin-C & -E contents, and SOD, CAT, GPx, and GR activities in the serum of liver cancer rats. The SCPg-AI-NCs treatment remarkably reduced the liver marker enzyme activities in the DEN-induced rats. The SCPg-AI-NCs treatment decreased the AFP and CEA contents and enhanced the Bax and caspase 3&9 activities in the DEN-induced rats. The SCPg-AI-NCs effectively decreased the cell viability and induced apoptosis in the HepG2 cells.

Conclusion

The present findings suggested that the formulated SCPg-AI-NCs remarkably inhibited the DEN-induced liver carcinogenesis in rats. These findings provide an evidence that SCPg-AI-NCs can be a promising anticancer nano-drug in the future to treat the liver carcinogenesis.

Dietary Organosulfur-Containing Compounds and Their Health-Promotion Mechanisms

Dietary organosulfur-containing compounds (DOSCs) in fruits, vegetables, and edible mushrooms may hold the key to the health-promotion benefits of these foods. Yet their action mechanisms are not clear, partially due to their high reactivity, which leads to the formation of complex compounds during postharvest processing. Among postharvest processing methods, thermal treatment is the most common way to process these edible plants rich in DOSCs, which undergo complex degradation pathways with the generation of numerous derivatives over a short time. At low temperatures, DOSCs are biotransformed slowly during fermentation to different metabolites (e.g., thiols, sulfides, peptides), whose distinctive biological activity remains largely unexplored. In this review, we discuss the bioavailability of DOSCs in human digestion before illustrating their potential mechanisms for health promotion related to cardiovascular health, cancer chemoprevention, and anti-inflammatory and antimicrobial activities. In particular, it is interesting that different DOSCs react with glutathione or cysteine, leading to the slow release of hydrogen sulfide (H2S), which has broad bioactivity in chronic disease prevention. In addition, DOSCs may interact with protein thiol groups of different protein targets of importance related to inflammation and phase II enzyme upregulation, among other action pathways critical for health promotion.

Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Perchlorate and chlorate in breast milk, infant formulas, baby supplementary food and the implications for infant exposure

Perchlorate and chlorate are ubiquitous pollutants in various types of foodstuffs, drinking water and environmental compartments. They have raised great concerns due to potential adverse effects on human thyroid functions. Dietary intake is considered as the predominant pathway for human exposure to perchlorate and chlorate. Nevertheless, data on human exposure to the chemicals above remain limited, particularly for the most vulnerable populations such as infants. In the present study, 62 breast milks, 53 infant formulas, 88 baby supplementary food and 50 tap water samples were collected in South China and the levels of perchlorate and chlorate were measured in these samples. Perchlorate and chlorate were frequently detected in more than 90% of measured samples. In these different types of samples, the median concentrations of perchlorate were 0.65 μg/L, 0.61 μg/kg, 0.56 μg/kg and 1.18 μg/L, respectively, while the median concentrations of chlorate were 1.73 μg/L, 2.48 μg/kg, 2.67 μg/kg and non-detected, respectively. Health risk assessment using hazard quotient suggested that perchlorate and chlorate exposure in the sampled baby food are not expected to increase the risk of an adverse health effect. To our knowledge, this is the first study simultaneously investigating perchlorate and chlorate exposure in Chinese infants via food intake.

Differentiated Effects of Allyl Isothiocyanate in Diabetic Rats: From Toxic to Beneficial Action

Allyl isothiocyanate (AITC), a constituent of Brassica family plants, has been reported to possess a high bioactivity in animal and human cells, showing ambiguous properties from adverse to beneficial ones. It was reported its genotoxic, carcinogenic, goitrogenic effects. On the other side, AITC has shown anti-cancer, cardioprotective, neuroprotective, and lately anti-obesity abilities. So far, its anti-diabetic effects are poorly explored. We tried to assess AITC action on carbohydrate, lipid and hormonal disorders in high fat diet-fed/streptozotocin diabetic rats. In this report, diabetic rats were treated intragastrically at doses 2.5, 5 and 25 mg/kg b.w./day of AITC for 2 weeks. Irrespectively of doses, AITC considerably lowered thyroid hormones (fT4, fT3), increased liver TG content, and also caused robust LDL-cholesterol and direct bilirubin concentration enhancement. Moreover, AITC at the highest dose caused pancreatic amylase and lipase drops and thyroid gland hypertrophy. AITC at 2.5 and 5 mg significantly reduced blood glucose levels along with robust beta-hydroxybutyric acid drop. Additionally, AITC at 5 mg improved insulin sensitivity (HOMA-IR index) in spite of reduced blood insulin. To conclude, despite amelioration of diabetic hyperglycemia by AITC, the adverse lipids and hormonal effects may exclude its use as a health-promoting compound in terms of anti-diabetic properties.

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.

Natural Products Targeting the Mitochondria in Cancers

There are abundant sources of anticancer drugs in nature that have a broad prospect in anticancer drug discovery. Natural compounds, with biological activities extracted from plants and marine and microbial metabolites, have significant antitumor effects, but their mechanisms are various. In addition to providing energy to cells, mitochondria are involved in processes, such as cell differentiation, cell signaling, and cell apoptosis, and they have the ability to regulate cell growth and cell cycle. Summing up recent data on how natural products regulate mitochondria is valuable for the development of anticancer drugs. This review focuses on natural products that have shown antitumor effects via regulating mitochondria. The search was done in PubMed, Web of Science, and Google Scholar databases, over a 5-year period, between 2015 and 2020, with a keyword search that focused on natural products, natural compounds, phytomedicine, Chinese medicine, antitumor, and mitochondria. Many natural products have been studied to have antitumor effects on different cells and can be further processed into useful drugs to treat cancer. In the process of searching for valuable new drugs, natural products such as terpenoids, flavonoids, saponins, alkaloids, coumarins, and quinones cover the broad space.

Characterisation of naturally occurring isothiocyanates as glutathione reductase inhibitors

Glutathione reductase (GR), an essential antioxidant enzyme against oxidative stress, has become an attractive drug target for the development of anticancer and antimalarial drugs. In this regard, we evaluated the naturally occurring isothiocyanates as promising GR inhibitors and elucidated the mechanism of action. It was found that benzyl isothiocyanate (BITC) and phenethyl isothiocyanate (PEITC) inhibited yeast GR (yGR) and human GR (hGR) in a time- and concentration-dependent manner. The K_i and k_inact of BITC against yGR were determined to be 259.87 µM and 0.0266 min⁻¹, respectively. The GR inhibition occurred only in the presence of NADPH and persisted after extensive dialysis. The tandem mass spectrometric analysis revealed that Cys⁶¹ rather than Cys⁶⁶ at the active site of yGR was mono-benzyl thiocarbamoylated by BITC. Inhibition of intracellular GR by BITC and PEITC in cultured cancer cells was also observed. BITC and PEITC were evaluated as competitive and irreversible inhibitors of GR.

Sensitivity of allyl isothiocyanate to induce apoptosis via ER stress and the mitochondrial pathway upon ROS production in colorectal adenocarcinoma cells

Allyl isothiocyanate (AITC), a bioactive phytochemical compound that is a constituent of dietary cruciferous vegetables, possesses promising chemopreventive and anticancer effects. However, reports of AITC exerting antitumor effects on apoptosis induction of colorectal cancer (CRC) cells in vitro are not well elucidated. The present study focused on the functional mechanism of the endoplasmic reticulum (ER) stress-based apoptotic machinery induced by AITC in human colorectal cancer HT-29 cells. Our results indicated that AITC decreased cell growth and number, reduced viability, and facilitated morphological changes of apoptotic cell death. DNA analysis by flow cytometry showed G2/M phase arrest, and alterations in the modulated protein levels caused by AITC were detected via western blot analysis. AITC also triggered vital intrinsic apoptotic factors (caspase-9/caspase-3 activity), disrupted mitochondrial membrane potential, and stimulated mitochondrial-related apoptotic molecules (e.g., cytochrome c, apoptotic protease activating factor 1, apoptosis-inducing factor, and endonuclease G). Additionally, AITC prompted induced cytosolic Ca²⁺ release and Ca²⁺-dependent ER stress-related signals, such as calpain 1, activating transcription factor 6α, glucose-regulated proteins 78 and 94, growth arrest- and DNA damage-inducible protein 153 (GADD153), and caspase-4. The level of reactive oxygen species (ROS) production was found to induce the hallmark of ER stress GADD153, proapoptotic marker caspase-3, and calpain activity after AITC treatment. Our findings showed for the first time that AITC induced G2/M phase arrest and apoptotic death via ROS-based ER stress and the intrinsic pathway (mitochondrial-dependent) in HT-29 cells. Overall, AITC may exert an epigenetic effect and is a potential bioactive compound for CRC treatment.

Propyl isothiocyanate induces apoptosis in gastric cancer cells by oxidative stress via glutathione depletion

Isothiocyanates are a group of compounds that exist in the majority of cruciferous plants. A number of isothiocyanates have been demonstrated to exhibit anticancer effects; however, antitumor properties of propyl isothiocyanate (PITC) have not been evaluated previously. In this study, the possible effects of PITC on gastric cancer (GC) cells were investigated, and the potential underlying mechanisms were explored. The results demonstrated that PITC inhibited cell viability of two GC cell lines and induced cell cycle arrest and apoptosis. Treatment with PITC promoted total glutathione depletion in GC cell lines, leading to reactive oxygen species accumulation and DNA damage, which activated the mitochondria-dependent and p53 signaling pathways to trigger apoptosis in GC cells. The effects of PITC were reversed by N-Acetyl-L-cysteine. The results of the present study revealed the potential mechanisms of PITC on apoptosis induction in GC cells, which may be mediated by mitochondria-dependent apoptosis and DNA damage.

Heterogeneity of cough hypersensitivity mediated by TRPV1 and TRPA1 in patients with chronic refractory cough

Background

The differential sensitivity of cough to antitussive therapies implies the existence of heterogeneity in cough hypersensitivity, but how such heterogeneity is expressed across individual patients is poorly understood. We investigated the phenotypes of cough hypersensitivity by examining transient receptor potential ankyrin 1 (TRPA1)- and transient receptor potential vanilloid 1 (TRPV1)-mediated cough sensitivity in patients with chronic refractory cough.

Methods

Using a selective TRPA1 agonist, allyl isothiocyanate (AITC), we established an AITC cough challenge as a measure of TRPA1-mediated cough sensitivity. The AITC cough challenge and the widely used capsaicin (a selective TRPV1 agonist) cough challenge were performed with 250 patients with chronic refractory cough and 56 healthy subjects. The concentration of AITC or capsaicin solution causing at least two (C2) and five coughs (C5) was recorded. Cough sensitivity was expressed as the mean (95% confidence interval) of log C5, and cough hypersensitivity was defined as a log C5 value lower than that of healthy subjects.

Results

A distinct concentration–response effect of inhaled AITC was identified both in patients with chronic refractory cough and in healthy subjects. Cough sensitivity to AITC and capsaicin was significantly higher in patients than in healthy subjects (AITC: 2.42 [2.37–2.48] vs 2.72 [2.66–2.78] mM, p = 0.001; capsaicin: 1.87 [1.75–1.98] vs 2.53 [2.36–2.70] μM, p = 0.001) and was higher in females than in males for both healthy subjects and patients (all p < 0.05). Among the 234 patients who completed both challenges, 25 (10.7%) exhibited hypersensitivity to both AITC and capsaicin, 44 (18.8%) showed hypersensitivity to AITC only, 28 (11.9%) showed hypersensitivity to capsaicin only, and 137 (58.6%) exhibited hypersensitivity to neither. Those with TRPA1- and/or TRPV1-mediated hypersensitivity were predominantly female, while those without TRPA1- and TRPV1-mediated hypersensitivity were mainly male.

Conclusions

Four phenotypes of cough hypersensitivity were identified by the activation of TRPV1 and TRPA1 channels, which supports the existence of heterogeneity in cough pathways and provides a new direction for personalized management of chronic refractory cough.

Trial registration

ClinicalTrials.gov NCT02591550.

The Role of Non-Coding RNAs and Isothiocyanates in Cancer

Cancer is the second leading cause of mortalities in the United States, only exceeded by heart disease. Current cancer treatments include chemotherapy, surgery, and/or radiation. Due to the often harsh effects of current cancer therapies, investigators are focusing their efforts on cancer prevention mediated by dietary phytochemicals. Since the discovery that cancer can be initiated by and progressed through both genetic and epigenetic pathways, there has been a significant surge in studies on epigenetic effects mediated by nutritive compounds. Isothiocyanates, naturally occurring molecules found in cruciferous vegetables, have been documented to exhibit many anticarcinogenic activities. Although isothiocyanates have been extensively documented as key players in epigenetic processes such as DNA methylation and histone modifications, their effects on non-coding RNAs is understudied. Non-coding RNAs are molecules that target mRNA production and repress protein translation and are known to be dysregulated in various human malignancies. Studies have used non-coding RNAs as novel targets for exploration in cancer therapy. This review focuses on the exploration of isothiocyanates and their effect on non-coding RNAs in cancer prevention and therapy.

Effect of allyl isothiocyanate on the viability and apoptosis of the human cervical cancer HeLa cell line in vitro

The present study aimed to investigate the effect of allyl isothiocyanate (AITC) on the viability and apoptosis of the human cervical cancer HeLa cell line in vitro, and to explore the potential underlying mechanisms of this. HeLa cells were treated with varying concentrations of AITC for different durations. The cell viability was then measured using a Cell Counting kit-8 assay and the apoptosis rate of the cells was detected using flow cytometry. Additionally, the B cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax) mRNA expression levels were determined by reverse transcription-quantitative polymerase chain reaction, while the Bax and Bcl-2 protein expression levels in cells were detected by western blot analysis. AITC was revealed to inhibit the viability of HeLa cells. AITC was revealed to induce the apoptosis of HeLa cells, as the apoptosis rate increased gradually with an increase in the dose. As the concentration of AITC increased, the Bax mRNA expression level increased, whilst the Bcl-2 mRNA expression level decreased. Furthermore, the Bax protein expression intensity increased whilst Bcl-2 protein expression intensity decreased, thereby resulting in a decrease in the ratio of Bcl-2/Bax proteins. AITC may inhibit cell viability by inducing the apoptosis of HeLa cells and this may be accounted for by the imbalance in the Bcl-2/Bax expression ratio.

Allyl Isothiocyanate Exhibits No Anticancer Activity in MDA-MB-231 Breast Cancer Cells

It was reported recently that allyl isothiocyanate (AITC) could inhibit various types of cancer cell growth. In the present study, we further investigated whether AITC could inhibit the growth of human breast cancer cells. Unexpectedly, we found that AITC did not inhibit, rather slightly promoted, the proliferation of MDA-MB-231 breast cancer cells, although it did have inhibitory effect on MCF-7 breast cancer cells. Cytofluorimetric analysis revealed that AITC (10 µM) did not induce apoptosis and cell cycle arrest in MDA-MB-231 cells. In addition, AITC significantly (p < 0.05) increased the expression of BCL-2 and mTOR genes and Beclin-1 protein in MDA-MB-231 cells. No significant changes in expression of PRKAA1 and PER2 genes, Caspase-8, Caspase-9, PARP, p-mTOR, and NF-κB p65 proteins were observed in these AITC-treated cells. Importantly, AITC displayed cytotoxic effect on MCF-10A human breast epithelial cell line. These observations suggest that AITC may not have inhibitory activity in MDA-MB-231 breast cancer cells. This in vitro study warrants more preclinical and clinical studies on the beneficial and harmful effects of AITC in healthy and cancer cells.