Involvement of the mitochondrial death pathway in chemopreventive benzyl isothiocyanate-induced apoptosis

Medicinal utilization and nutritional properties of drumstick (Moringa oleifera)-A comprehensive review

The tropical and subtropical regions of the world support the growth of the Indian plant Moringa oleifera. It usually goes by the name drumstick tree or horseradish tree and thrives in warm climates. The leaves of the M. oleifera tree are now frequently used as nutrients and nutraceuticals due to their availability of various minerals. While having only very minor antinutritional effects, the leaves are abundant in many beneficial compounds. A recent review of the bioactive components and activity of moringa leaves has focused on both in vivo and in vitro studies. Drumstick leaves have antidiabetic qualities, anti-inflammatory, anticancer, and antibacterial qualities among other health benefits. Phytochemicals, in addition to minerals and vitamins, are abundant in this vegetable. The majority of these effects, according to a review in the literature, are mostly brought on by the presence of carotenoids, glucosinolates, and phytochemicals. As a value-added component in the production of wholesome meals, moringa is becoming more popular. Despite extensive research into locating and quantifying these advantageous elements in drumstick leaves, bioavailability and bioaccessibility studies were carried out. Beneficial photochemicals are absorbed and digested through incredibly intricate processes that involve several physicochemical and physiological interactions. Therefore, the biological impact of food may be attributed to its various metabolites that can access particular areas of action rather than its original substances. This body of literature offers the most recent findings in scientific research on the bioavailability, health advantages, nutritional profiles, and bioactive activities of moringa leaves as they relate to their use in a range of food products. Drumsticks are frequently used as a food element that promotes health because of their potent protection against a variety of ailments and the presence of environmental pollutants.

Synergistic Action of Benzyl Isothiocyanate and Sorafenib in a Nanoparticle Delivery System for Enhanced Triple-Negative Breast Cancer Treatment

Triple-negative breast cancer (TNBC) presents a therapeutic challenge due to its complex pathology and limited treatment options. Addressing this challenge, our study focuses on the effectiveness of combination therapy, which has recently become a critical strategy in cancer treatment, improving therapeutic outcomes and combating drug resistance and metastasis. We explored a novel combination therapy employing Benzyl isothiocyanate (BITC) and Sorafenib (SOR) and their nanoformulation, aiming to enhance therapeutic outcomes against TNBC. Through a series of in vitro assays, we assessed the cytotoxic effects of BITC and SOR, both free and encapsulated. The BITC-SOR-loaded nanoparticles (NPs) were synthesized using an amphiphilic copolymer, which demonstrated a uniform spherical morphology and favorable size distribution. The encapsulation efficiencies, as well as the sustained release profiles at varied pH levels, were quantified, revealing distinct kinetics that were well-modeled by the Korsmeyer-Peppas equation. The NP delivery system showed a marked dose-dependent cytotoxicity towards TNBC cells, with an IC50 of 7.8 μM for MDA-MB-231 cells, indicating improved efficacy over free drugs, while exhibiting minimal toxicity toward normal breast cells. Furthermore, the NPs significantly inhibited cell migration and invasion in TNBC models, surpassing the effects of free drugs. These findings underscore the potential of BITC-SOR-NPs as a promising therapeutic approach for TNBC, offering targeted delivery while minimizing systemic toxicity.

Moringa oleifera: A Review on the Antiproliferative Potential in Breast Cancer Cells

The global burden of female breast cancer and associated deaths has become a major concern. Many chemotherapeutic agents, such as doxorubicin, have been shown to have adverse side effects. The development of multi-drug resistance is a common occurrence, contributing to chemotherapeutic failure. The resistance of breast cancer cells to drug treatment leads to a decline in the treatment efficacy and an increase in cancer recurrence. Therefore, action is required to produce alternative drug therapies, such as herbal drugs. Herbal drugs have been proven to be beneficial in treating illnesses, including cancer. This review aims to highlight the antiproliferative potential of Moringa oleifera (MO), a medicinal tree native to India and indigenous to Africa, in breast cancer cells. Although MO is not yet considered a commercial chemopreventive drug, previous studies have indicated that it could become a chemotherapeutic agent. The possible antiproliferative potential of MO aqueous leaf extract has been previously proven through its antioxidant potential as well as its ability to induce apoptosis. This review will provide an increased understanding of the effect that MO aqueous leaf extract could potentially have against breast cancer.

Benzyl isothiocyanate and its metabolites inhibit cell proliferation through protein modification in mouse preosteoclast RAW264.7 cells

Benzyl isothiocyanate (BITC), derived from cruciferous vegetables, is an organosulfur compound exerting antiproliferative effects in several human cancer cells. In this study, we assessed BITC as a potential osteoclastogenesis inhibitor and investigated its underlying mechanism. BITC at 5 μM significantly decreased the viability of the osteoclast-like differentiating RAW264.7 cells, coinciding with the downregulation of the primary biomarkers for osteoclast differentiation, such as the tartrate-resistant acid phosphatase activity and nuclear factor of activated T-cells gene expression. Not only BITC but also its metabolites, inhibited cell proliferation in the normal RAW264.7 cells, suggesting that BITC shows an anti-osteoclastogenesis effect in vivo after its ingestion and metabolism, possibly through an antiproliferative action. Both BITC and its metabolites also enhanced the DNA fragmentation and the caspase-3 activity, whereas their higher concentrations tended to suppress these effects. BITC was intracellularly accumulated when the cells were treated with its metabolites via their degradation into the free form. A quantitative experiment using the proteolysis/high performance liquid chromatography technique showed that the amount of BITC-lysine thiourea in the cells was also increased in a time-dependent manner, suggesting that lysine modification of the cellular proteins actually took place in the cells treated by BITC. Among the cellular proteins, the cleaved caspase-3 was identified as a potential target for lysine modification by BITC. Taken together, BITC dissociated from its metabolites as well as its free form might modulate osteoclastogenesis, possibly through inhibition of cell proliferation by protein modification.

GC/MS Profiling and Ex Vivo Antibacterial Activity of Salvadora persica (Siwak) against Enterococcus faecalis as Intracanal Medicament

INTRODUCTION

Salvadora persica L. (S. persica, Siwak) has been used for many centuries as oral hygiene tools, particularly in Saudi Arabia. This study aimed to assess the effectiveness of S. persica petroleum ether extract (SPE) as an intracanal bactericidal for endodontic treatment against Enterococcus faecalis. Calcium hydroxide Ca(OH)₂ gold standard intracanal medicament was used for comparison.

METHODS

The gas chromatography mass spectrometry (GC/MS) analysis was carried out to identify the components of SPE. First, the consistency of SPE was accomplished according to ANSI/ADA specification no 57. Forty-five single-rooted mandibular premolars were infected with that of E. faecalis suspension. Colony-forming units (CFU) were counted before the medicaments' application (CFU-1) and after seven days of their applications (CFU-2). Group I: SPE, Group II: positive control Ca(OH)₂, and Group III: saline solution negative control. The microdilution method was applied to determine minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of SPE.

RESULTS

Thirty-two compounds were identified (89.09%), with main components of benzyl isothiocyanate (BITC) (33.32%) and steroids (34%). CFU before and after using SPE and Ca(OH)₂ recorded a statistically significant reduction in bacterial count (P=0.006) and (P=0.01), respectively. There was an insignificant difference between CFU after using SPE and Ca(OH)₂ (P=0.210). On the contrary, comparing both medicaments with the negative control saline group resulted in significant differences, (P=0.001) and (P=0.007), respectively. Moreover, the equality of minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) of SPE is recorded.

CONCLUSION

This finding could be referred to the high content of bactericidal BITC in synergism with other antimicrobial components, representing 70.71% of SPE. Thus, SPE is a good candidate as an intracanal medicament, which warrants further investigation.

Metabolomics and Physiological Approach to Understand Allelopathic Effect of Horseradish Extract on Onion Root and Lettuce Seed as Model Organism

In the present study, we assessed the allelopathic effects of various concentrations (0%, 0.1%, 0.2%, and 0.3%) of horseradish root extract (HRE) on onion root. The average growth of onion root tips during the 0% HRE treatment (deionized water treatment) was 0.9 cm/day, which was the highest among the growth rates obtained with all HRE treatments. Moreover, the average growth during 0.3% HRE treatment was 0.1 cm/day. During cell cycle analysis, the mitotic phase fraction of the control (deionized water treatment) cells was 6.5% of all dividing cells, with this percentage being the highest among the values obtained for all treatment groups. In the control group, all cell cycle phases were identified; however, in the 0.1%, 0.2%, and 0.3% treatment groups, telophase was not identified. The ROS accumulation area of the onion root decreased, as the HRE treatment concentration increased. In the control root, the area of dead tissue was 0%; however, in the 0.1% and 0.2% HRE treatment roots, the ratio was 5% and 50%, respectively. These findings indicate that the allelopathic effect of HRE depends on the concentration of HRE applied to the onion root.

Nutritional significance and therapeutic potential of Moringa oleifera: The wonder plant

Moringa oleifera is a multi-purpose plant and a comprehensive source of dietary components such as proteins, essential amino acids, vitamins, antioxidants, etc. The plant is also a rich source of other bioactive components, including flavonoids, glucosinolates, isothiocyanates, alkaloids, terpenoids, phenolics, etc. Incorporating M. oleifera in diet can improve the nutritional status of pregnant and nursing mothers and helps to combat malnutrition and iron deficiency anemia (IDA) among children. The phytochemicals and secondary metabolites, especially the polyphenolic compounds from Moringa, have a significant free-radical scavenging effect attributed to this plant's therapeutic potential. Investigations targeting to explore M. oleifera for its nutritional makeup, novel bioactive components, and analysis of their health-promoting attributes have received much attention. This review demonstrates an overview of recent (past ten years) advancements and patenting activity in discovering different parts of M. oleifera plant for providing adequate nutritive and bioactive components. The pharmacological potential and action mechanisms of M. oleifera in many diseases like diabetes mellitus, cancer, hypertension, ulcer, etc., are also discussed. PRACTICAL APPLICATIONS: Moringa oleifera is a vital plant that has a varied set of nutritional and therapeutic properties. The indigenous components of Moringa can treat humankind of its diseases and contribute to overall health. The qualitative and functional characteristics of its components indicate possible commercial exploitation of this high-value plant by utilizing its plant parts in many proprietary medicines and nutraceuticals. In conclusion, the Moringa plant needs to be used commercially. It can lead to tremendous economic development if the industries and researchers exploit its potential for highly nutritional super food and therapeutic application by undertaking further research to corroborate earlier studies.

Moringa oleifera is a Prominent Source of Nutrients with Potential Health Benefits

Nowadays, the socioeconomic status has been changed a lot, so people are now more concerned about their life style and health. They have knowledge about the detrimental effects of synthetic products. That is why they are interested in natural products. Utilization of natural products of plant origin having fewer side effects has gained popularity over the years. There is immense scope for natural products that can intimate health benefits beyond traditional nutrients. Moringa oleifera is one such tree having tremendous nutritional and medicinal benefits. It is rich in macro- and micronutrients and other bioactive compounds which are important for normal functioning of the body and prevention of certain diseases. Leaves, flowers, seeds, and almost all parts of this tree are edible and have immense therapeutic properties including antidiabetic, anticancer, antiulcer, antimicrobial, and antioxidant. Most of the recent studies suggested that Moringa should be used as a functional ingredient in food. The aim of this review is to focus the use of Moringa oleifera as a potential ingredient in food products.

A multidrug resistance-associated protein inhibitor is a potential enhancer of the benzyl isothiocyanate-induced apoptosis induction in human colorectal cancer cells

The increasing drug efflux through the ATP-binding cassette (ABC) transporters is the most plausible mechanism that mediates resistance to the anticancer phytochemicals, such as benzyl isothiocyanate (BITC), as well as chemotherapy drugs. To identify a potential component to overcome this resistance by combinatory utilization, we focused on multidrug resistance-associated proteins (MRPs) pumping various drug metabolites with glutathione as well as the organic anions. The pharmacological treatment of an MRP inhibitor, MK571, significantly potentiated the BITC-induced antiproliferation, coincided with the enhanced accumulation of BITC and glutathione in human colorectal cancer HCT-116 cells. MK571 also enhanced the apoptosis induction as well as activation of the mitogen-activated protein kinases and caspase-3, whereas it did not affect their basal levels. These results suggested that, since MRPs might play a pivotal role in the BITC efflux, MK571 potentiates the BITC-induced antiproliferation in human colorectal cancer cells through inhibition of the glutathione-dependent BITC efflux.

An Evaluation of the Anti-Carcinogenic Response of Major Isothiocyanates in Non-Metastatic and Metastatic Melanoma Cells

Malignant melanoma is one of the most deadly types of solid cancers, a property mainly attributed to its highly aggressive metastatic form. On the other hand, different classes of isothiocyanates, a class of phytochemicals, present in cruciferous vegetables have been characterized by considerable anti-cancer activity in both in vitro and in vivo experimental models. In the current study, we investigated the anti-cancer response of five isothiocyanates in an in vitro model of melanoma consisting of non-metastatic (A375, B16F-10) and metastatic (VMM1, Hs294T) malignant melanoma as well as non-melanoma epidermoid carcinoma (A431) and non-tumorigenic melanocyte-neighboring keratinocyte (HaCaT) cells. Our aim was to compare different endpoints of cytotoxicity (e.g., reactive oxygen species, intracellular glutathione content, cell cycle growth arrest, apoptosis and necrosis) descriptive of an anti-cancer response between non-metastatic and metastatic melanoma as well as non-melanoma epidermoid carcinoma and non-tumorigenic cells. Our results showed that exposure to isothiocyanates induced an increase in intracellular reactive oxygen species and glutathione contents between non-metastatic and metastatic melanoma cells. The distribution of cell cycle phases followed a similar pattern in a manner where non-metastatic and metastatic melanoma cells appeared to be growth arrested at the G2/M phase while elevated levels of metastatic melanoma cells were shown to be at sub G1 phase, an indicator of necrotic cell death. Finally, metastatic melanoma cells were more sensitive apoptosis and/or necrosis as higher levels were observed compared to non-melanoma epidermoid carcinoma and non-tumorigenic cells. In general, non-melanoma epidermoid carcinoma and non-tumorigenic cells were more resistant under any experimental exposure condition. Overall, our study provides further evidence for the potential development of isothiocyanates as promising anti-cancer agents against non-metastatic and metastatic melanoma cells, a property specific for these cells and not shared by non-melanoma epidermoid carcinoma or non-tumorigenic melanocyte cells.

Benzyl Isothiocyanate Produced by Garden Cress (Lepidium sativum) Prevents Accumulation of Hepatic Lipids

We determined the physiological effects of glucotropaeolin-rich lyophilized garden cress sprout powder (GC) administered to fasting and nonfasting mice. High-performance liquid chromatography analysis revealed glucotropaeolin (57.4±1.1 mg/g dry weight) as a major phytochemical constituent of GC. Decreasing tendency in body weight and feeding efficiency ratio were detected in the group of mice fed 0.05% (w/w) GC (GC0.05). Nonfasting mice exhibited significantly lower liver weights that were unchanged after fasting. Decreased total lipid (TL) and triglyceride (TG) levels in the liver were detected in the nonfasted GC0.01 and GC0.05 groups, but only in TLs of the fasted groups. The levels of plasma TGs and nonesterified fatty acids of the GC0.05 group, which remained unchanged during nonfasting, decreased after fasting. To determine its effects on the accumulation of lipids in the liver, the glucotropaeolin aglycone, benzyl isothiocyanate (BITC), was added to the liver-derived HepG2 human cell line cultured in a medium containing a high concentration of D-glucose (4,500 mg/L D-glucose) (HG group) or 1 mM oleic acid (SO group). Toxicity was not detected when cells were treated with as much as 5 μM BITC; however, lipid accumulation was inhibited by BITC in a concentration-dependent manner in the HG groups. The same effect was observed when 2 μM BITC was added to the diet of the SO groups. These results suggest that moderate levels of GC or BITC are useful for reducing liver and plasma TGs.

Natural Agents Targeting Mitochondria in Cancer

Mitochondria are the key energy provider to highly proliferating cancer cells, and are subsequently considered one of the critical targets in cancer therapeutics. Several compounds have been studied for their mitochondria-targeting ability in cancer cells. These studies’ outcomes have led to the invention of “mitocans”, a category of drug known to precisely target the cancer cells’ mitochondria. Based upon their mode of action, mitocans have been divided into eight classes. To date, different synthetic compounds have been suggested to be potential mitocans, but unfortunately, they are observed to exert adverse effects. Many studies have been published justifying the medicinal significance of large numbers of natural agents for their mitochondria-targeting ability and anticancer activities with minimal or no side effects. However, these natural agents have never been critically analyzed for their mitochondria-targeting activity. This review aims to evaluate the various natural agents affecting mitochondria and categorize them in different classes. Henceforth, our study may further support the potential mitocan behavior of various natural agents and highlight their significance in formulating novel potential anticancer therapeutics.

Benzyl Isothiocyanate Induces Apoptosis via Reactive Oxygen Species-Initiated Mitochondrial Dysfunction and DR4 and DR5 Death Receptor Activation in Gastric Adenocarcinoma Cells

Benzyl isothiocyanate (BITC) is known to inhibit the metastasis of gastric cancer cells but further studies are needed to confirm its chemotherapeutic potential against gastric cancer. In this study, we observed cell shrinkage and morphological changes in one of the gastric adenocarcinoma cell lines, the AGS cells, after BITC treatment. We performed 3-(4,5-dimethyl-2-thiazolyl)-2,5- diphenyl-2H-tetrazolium bromide (MTT) assay, a cell viability assay, and found that BITC decreased AGS cell viability. Reactive oxygen species (ROS) analyses using 2',7'-dichlorofluorescin diacetate (DCFDA) revealed that BITC-induced cell death involved intracellular ROS production, which resulted in mitochondrial dysfunction. Additionally, cell viability was partially restored when BITC-treated AGS cells were preincubated with glutathione (GSH). Western blotting indicated that BITC regulated the expressions of the mitochondria-mediated apoptosis signaling molecules, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), and cytochrome c (Cyt c). In addition, BITC increased death receptor DR5 expression, and activated the cysteine-aspartic proteases (caspases) cascade. Overall, our results showed that BITC triggers apoptosis in AGS cells via the apoptotic pathways involved in ROS-promoted mitochondrial dysfunction and death receptor activation.

Yeast screening system reveals the inhibitory mechanism of cancer cell proliferation by benzyl isothiocyanate through down-regulation of Mis12

Benzyl isothiocyanate (BITC) is a naturally-occurring isothiocyanate derived from cruciferous vegetables. BITC has been reported to inhibit the proliferation of various cancer cells, which is believed to be important for the inhibition of tumorigenesis. However, the detailed mechanisms of action remain unclear. In this study, we employed a budding yeast Saccharomyces cerevisiae as a model organism for screening. Twelve genes including MTW1 were identified as the overexpression suppressors for the antiproliferative effect of BITC using the genome-wide multi-copy plasmid collection for S. cerevisiae. Overexpression of the kinetochore protein Mtw1 counteracts the antiproliferative effect of BITC in yeast. The inhibitory effect of BITC on the proliferation of human colon cancer HCT-116 cells was consistently suppressed by the overexpression of Mis12, a human orthologue of Mtw1, and enhanced by the knockdown of Mis12. We also found that BITC increased the phosphorylated and ubiquitinated Mis12 level with consequent reduction of Mis12, suggesting that BITC degrades Mis12 through an ubiquitin-proteasome system. Furthermore, cell cycle analysis showed that the change in the Mis12 level affected the cell cycle distribution and the sensitivity to the BITC-induced apoptosis. These results provide evidence that BITC suppresses cell proliferation through the post-transcriptional regulation of the kinetochore protein Mis12.

Anti-Carcinogenic Glucosinolates in Cruciferous Vegetables and Their Antagonistic Effects on Prevention of Cancers

Glucosinolates (GSL) are naturally occurring β-d-thioglucosides found across the cruciferous vegetables. Core structure formation and side-chain modifications lead to the synthesis of more than 200 types of GSLs in Brassicaceae. Isothiocyanates (ITCs) are chemoprotectives produced as the hydrolyzed product of GSLs by enzyme myrosinase. Benzyl isothiocyanate (BITC), phenethyl isothiocyanate (PEITC) and sulforaphane ([1-isothioyanato-4-(methyl-sulfinyl) butane], SFN) are potential ITCs with efficient therapeutic properties. Beneficial role of BITC, PEITC and SFN was widely studied against various cancers such as breast, brain, blood, bone, colon, gastric, liver, lung, oral, pancreatic, prostate and so forth. Nuclear factor-erythroid 2-related factor-2 (Nrf2) is a key transcription factor limits the tumor progression. Induction of ARE (antioxidant responsive element) and ROS (reactive oxygen species) mediated pathway by Nrf2 controls the activity of nuclear factor-kappaB (NF-κB). NF-κB has a double edged role in the immune system. NF-κB induced during inflammatory is essential for an acute immune process. Meanwhile, hyper activation of NF-κB transcription factors was witnessed in the tumor cells. Antagonistic activity of BITC, PEITC and SFN against cancer was related with the direct/indirect interaction with Nrf2 and NF-κB protein. All three ITCs able to disrupts Nrf2-Keap1 complex and translocate Nrf2 into the nucleus. BITC have the affinity to inhibit the NF-κB than SFN due to the presence of additional benzyl structure. This review will give the overview on chemo preventive of ITCs against several types of cancer cell lines. We have also discussed the molecular interaction(s) of the antagonistic effect of BITC, PEITC and SFN with Nrf2 and NF-κB to prevent cancer.

Intake of glucosinolates and risk of coronary heart disease in three large prospective cohorts of US men and women

Importance

Glucosinolates, a group of phytochemicals abundant in cruciferous vegetables, may have cardioprotective properties. However, no prospective study has evaluated the association of intake of glucosinolates with the risk of coronary heart disease (CHD).

Objective

The objective of the study was to evaluate the association between the intake of glucosinolates and incident CHD in US men and women.

Design

Prospective longitudinal cohort study.

Setting

Health professionals in the USA.

Participants

We followed 74,241 women in the Nurses’ Health Study (NHS; 1984–2012), 94,163 women in the NHSII (1991–2013), and 42,170 men in the Health Professionals Follow-Up Study (1986–2012), who were free of cardiovascular disease and cancer at baseline.

Exposure

Glucosinolate intake was assessed using validated semi-quantitative food frequency questionnaires at baseline and updated every 2–4 years during follow-up.

Main outcome measures

Incident cases of CHD were confirmed by medical record review.

Results

During 4,824,001 person-years of follow-up, 8,010 cases of CHD were identified in the three cohorts. After adjustment for major lifestyle and dietary risk factors of CHD, weak but significantly positive associations were observed for glucosinolates with CHD risk when comparing the top with bottom quintiles (hazard ratio [HR]:1.09; 95% CI: 1.01, 1.17; P_trend<0.001). Higher intakes of three major subtypes of glucosinolates were consistently associated with a higher CHD risk, although the association for indolylglucosinolate did not achieve statistical significance. Regarding cruciferous vegetable intake, participants who consumed one or more servings per week of Brussels sprouts (HR: 1.16; 95% CI: 1.06, 1.26; P<0.001) and cabbage (HR: 1.09; 95% CI: 1.02, 1.17; P=0.009) had a significantly higher CHD risk than those who consumed these cruciferous vegetables less than once per month.

Conclusion and relevance

In these three prospective cohort studies, dietary glucosinolate intake was associated with a slightly higher risk of CHD in US adults. These results warrant replications in further studies including biomarker-based studies. Further studies are needed to confirm these findings and elucidate mechanistic pathways that may underlie these associations.

Apoptosis as a Mechanism of the Cancer Chemopreventive Activity of Glucosinolates: a Review

Cruciferous vegetables are a rich source of glucosinolates that have established anti-carcinogenic activity. Naturally-occurring glucosinolates and their derivative isothiocyanates (ITCs), generated as a result of their enzymatic degradation catalysed by myrosinase, have been linked to low cancer incidence in epidemiological studies, and in animal models isothiocyanates suppressed chemically-induced tumorigenesis. The prospective effect of isothiocyanates as anti-carcinogenic agent has been much explored as cytotoxic against wide array of cancer cell lines and being explored for the development of new anticancer drugs. However, the mechanisms of isothiocyanates in inducing apoptosis against tumor cell lines are still largely disregarded. A number of mechanisms are believed to be involved in the glucosinolate-induced suppression of carcinogenesis, including the induction of apoptosis, biotransformation of xenobiotic metabolism, oxidative stress, alteration of caspase activity, angiogenesis, histone deacytylation and cell cycle arrest. The molecular mechanisms through which isothiocyanates stimulate apoptosis in cancer cell lines have not so far been clearly defined. This review summarizes the underlying mechanisms through which isothiocyanates modify the apoptotic pathway leading to cell death.

Physiological relevance of covalent protein modification by dietary isothiocyanates

Isothiocyanates (ITCs), naturally occurring in abundance in cruciferous vegetables, are the most well-studied organosulfur compounds having an electrophilic reactivity. ITCs have been accepted as major ingredients of these vegetables that afford their health promoting potentials. ITCs are able to modulate protein functions related to drug-metabolizing enzymes, transporters, kinases and phosphatases, etc. One of the most important questions about the molecular basis for the health promoting effects of ITCs is how they modulate cellular target proteins. Although the molecular targets of ITCs remains to be validated, dietary modulation of the target proteins via covalent modification by ITCs should be one of the promising strategies for the protection of cells against oxidative and inflammatory damage. This review discusses the plausible target proteins of dietary ITCs with an emphasis on possible involvement of protein modification in their health promoting effects. The fundamental knowledge of ITCs is also included with consideration of the chemistry, intracellular behavior, and metabolism.

Benzyl isothiocyanate induces reactive oxygen species-initiated autophagy and apoptosis in human prostate cancer cells

Benzyl isothiocyanate (BITC) in cruciferous plants, which are part of the human diet, has been shown to induce apoptosis in various types of cancer. In this study, we show that BITC effectively suppresses the growth of cultured human prostate cancer cells (CRW-22Rv1 and PC3) by causing mitochondrial membrane potential loss, caspase 3/7 activation and DNA fragmentation. Furthermore, BITC induces ROS generation in these cells. The induction of apoptosis by BITC was significantly attenuated in the presence of N-acetylcysteine (NAC) and catalase (CAT), well-studied ROS scavengers. The induction of autophagy in BITC-treated cells were also diminished by the application of NAC or CAT. In addition, BITC-induced apoptosis and autophagy were both enhanced by the pretreatment of catalase inhibitor, 3-Amino-1,2,4-triazole (3-AT). Pretreatment with specific inhibitors of autophagy (3-methyladenine or bafilomycin A1) or apoptosis (Z-VAD-FMK) reduced BITC-induced autophagy and apoptosis, respectively, but did not abolish BITC-induced ROS generation. In conclusion, the present study provides evidences that BITC caused prostate cancer cell death was dependent on the ROS status, and clarified the mechanism underlying BITC-induced cell death, which involves the induction of ROS production, autophagy and apoptosis, and the relationship between these three important processes.

Inhibition of phosphatidylinositide 3-kinase ameliorates antiproliferation by benzyl isothiocyanate in human colon cancer cells

In the present study, we clarified the role of phosphatidylinositide 3-kinase (PI3K) in antiproliferation induced by benzyl isothiocyanate (BITC) in human colorectal cancer cells. BITC simultaneously activated the PI3K/Akt/forkhead box O (FoxO) pathway, whereas it significantly inhibited the proliferation in human colorectal cancer cells. Inhibitory experiments using a PI3K selective inhibitor, LY294002 or NVP-BEZ235, significantly enhanced the BITC-induced antiproliferation and apoptotic cell population with the attenuation of the BITC-induced activation of the PI3K/Akt/FoxO survival pathway. Furthermore, BITC enhanced the insulin-activated PI3K/Akt/FoxO pathway, possibly through its inhibition of the protein tyrosine phosphatase 1B enzymatic activity. Taken together, these results suggested that the PI3K/Akt/FoxO pathway negatively regulates the BITC-induced antiproliferation in human colorectal cancer cells.

Transcriptomic alterations in Sitophilus zeamais in response to allyl isothiocyanate fumigation

To study the fumigation mechanisms of Allyl isothiocyanate (AITC) a promising biorational alternative to present fumigants (phosphine and methyl bromide), and provide theoretical basis for its further development in the control of stored grain pests, this research presents a transcriptome analysis of Sitophilus zeamais fumigated with AITC at the concentration of LC₅₀ (5.69μg/mL) and control over 8h. 21,869,022 and 23,873,110 clean reads in insects fumigated with AITC and control were gained, respectively. The results of RNA-seq were confirmed by qRT-PCR determination of the expression levels of NADH dehydrogenase subunit 6 and Vacuolar ATP synthase subunit B in the insects fumigated with AITC at different concentrations. After enrichment analysis of differentially expressed genes, 117 over-expressed and 271 down-regulated transcripts were gained. Following GO enrichment, these transcripts were classified into 38 GO subgroups (at level 2), and the majority enriched GO terms were "Binding" "Cell process" and "metabolic". KEGG enrichment analysis showed that the majority enriched pathway were "Folding, sorting and degradation", "Transport and catabolism", "Energy metabolism", and "Carbohydrate metabolism". Connected with previous researches on mechanisms of isothiocyanates, cytoskeleton collapse and mitochondria dysfunction are proposed to be significant lethal mechanisms of AITC.

Novel phosphonate analogs of sulforaphane: Synthesis, in vitro and in vivo anticancer activity

A library of over forty, novel, structurally diverse phosphonate analogs of sulforaphane (P-ITCs) were designed, synthesized and fully characterized. All compounds were evaluated for antiproliferative activity in vitro on Lovo and LoVo/DX colon cancer cell lines. All compounds exhibited high antiproliferative activity, comparable or higher to the activity of naturally occurring benzyl isothiocyanate and sulforaphane. Assessment of the mechanisms of action of selected compounds revealed their potential as inducers of G₂/M cell cycle arrest and apoptosis. Further antiproliferative studies for selected compounds with the use of a set of selected cell lines derived from colon, lung, mammary gland and uterus as well as normal murine fibroblasts were performed. In vivo studies of the analyzed phosphonate analogs of sulforaphane showed lower activity in comparison with those of benzyl isothiocyanate. Our studies demonstrated that newly synthesized P-ITCs can be used for as a starting point for the synthesis of novel isothiocyanates with higher anticancer activity in the future.

Mitochondrial dysfunction in cancer chemoprevention by phytochemicals from dietary and medicinal plants

Cancer chemoprevention, a scientific term coined by Dr. Sporn in the late seventies, implies use of natural or synthetic chemicals to block, delay or reverse carcinogenesis. Phytochemicals derived from edible and medicinal plants have been studied rather extensively for cancer chemoprevention using preclinical models in the past few decades. Nevertheless, some of these agents (e.g., isothiocyanates from cruciferous vegetables like broccoli and watercress) have already entered into clinical investigations. Examples of widely studied and highly promising phytochemicals from edible and medicinal plants include cruciferous vegetable constituents (phenethyl isothiocyanate, benzyl isothiocyanate, and sulforaphane), withaferin A (WA) derived from a medicinal plant (Withania somnifera) used heavily in Asia, and an oriental medicine plant component honokiol (HNK). An interesting feature of these structurally-diverse phytochemicals is that they target mitochondria to provoke cancer cell-selective death program. Mechanisms underlying cell death induction by commonly studied phytochemicals have been discussed rather extensively and thus are not covered in this review article. Instead, the primary focus of this perspective is to discuss experimental evidence pointing to mitochondrial dysfunction in cancer chemoprevention by promising phytochemicals.

Alpha fetoprotein antagonises benzyl isothiocyanate inhibition of the malignant behaviors of hepatocellular carcinoma cells

Benzyl isothiocyanate (BITC) is a dietary isothiocyanate derived from cruciferous vegetables. Recent studies showed that BITC inhibited the growth of many cancer cells, including hepatocellular carcinoma (HCC) cells. Alpha-fetoprotein (AFP) is a important molecule for promoting progression of HCC, in the present investigation, we explore the influence of AFP on the role of BITC in the malignant behaviours of HCC cells, and the potential underlying mechanisms. We found thatBITC inhibited viability, migration, invasion and induced apoptosis of human liver cancer cell lines, Bel 7402(AFP producer) and HLE(non-AFP producer) cells in vitro. The role of BITC involve in promoting actived-caspase-3 and PARP-1 expression, and enhancing caspase-3 activity but decreasing MMP-2/9, survivin and CXCR4 expression. AFP antagonized the effect of BITC. This study suggests that BITC induced significant reductions in the viability of HCC cell lines. BITC may activate caspase-3 signal and inhibit the expression of growth- and metastasis-related proteins; AFP is an pivotal molecule for the HCC chemo-resistance of BITC.

Chemical alterations and regulations of biomolecules in lifestyle-related diseases

We know experientially that not only nutrient factors but also non-nutritive functional food factors are playing important roles in maintenance of homeostasis, health promotion, and disease prevention. Although some of these effective behaviors are supported by accumulating scientific evidences, it is in general difficult to determine properly in human. Therefore, the discovering of novel biomarker and developments of the analytical method are one of the prudent strategies to understand disease etiology and evaluate efficacies of functional food factors via monitoring the pathophysiological alteration in live body, tissue, and cells. This review describes recent our findings on (1) formation mechanism, bioactivities, quantitative determination of cholesterol ozonolysis product, secosterol as possible biomarker for lifestyle-related disease, and (2) chemical biology approach for the investigating molecular mechanisms of most promising cancer chemopreventive food factors, isothiocyanate-inducing bioactivities.

Amiprophosmethyl-induced efficient in vitro production of polyploids in raphanobrassica with the aid of aminoethoxyvinylglycine (AVG) in the culture medium

Optimum conditions for obtaining tetraploid were investigated in raphanobrassica, the intergeneric hybrid between radish (Raphanus sativus) and kale (Brassica oleracea var. acephala) by treating in vitro plants with an anti-mitotic agent, amiprophosmethyl (APM). Initially, no tetraploids but hexaploids and octaploids were induced by the treatments. Although the leaves of these polyploids of raphanobrassica showed chlorosis during subcultures in in vitro conditions, the chlorosis could be successfully prevented by the ethylene inhibitors, both AVG and AgNO3. Based on this result, AVG was added into medium used for the culture after the chromosome doubling treatment, which subsequently resulted in increased survival rates of the treated plant materials as well as increased production rates of polyploids including tetraploid. These polyploid plants showed obviously different characters from the original diploid plant. The tetraploid plant had bigger sizes in shoot, flower and leaf, and more number of leaves than the diploid. On the other hand, the hexaploid and octaploid plants had smaller sizes in shoots and leaves, and less number of leaves than the diploid. Concentration of glucosinolates, functional substances of Brassicaceae crops, did not significantly differ between diploid and tetraploid of raphanobrassica, but reduced in hexaploid and octaploid.

Mechanisms of the Anticancer Effects of Isothiocyanates

Cancer results from aberrant signaling pathways that result in uncontrolled cellular proliferation. The epidemiological studies have shown a strong inverse correlation between dietary consumption of cruciferous vegetables and incidences of cancer. Isothiocyanates (ITCs) are present in cruciferous vegetables like broccoli, cabbage, watercress, etc. and are identified as the major active constituents. Several mechanistic studies have demonstrated chemopreventive and chemotherapeutic activity of ITCs against various tumor types. ITCs exert anticancer activity by suppressing various critical hallmarks of cancer like cellular proliferation, angiogenesis, apoptosis, metastasis, etc., in vitro as well as in preclinical animal model. ITCs also generate reactive oxygen species to induce apoptosis in cancer cells. Due to promising preclinical results, few ITCs have also advanced to clinical trials. This chapter provides a candid review on the chemopreventive and chemotherapeutic activity of various major ITCs.

Cruciferous vegetables, isothiocyanates, and prevention of bladder cancer

Approximately 80% of human bladder cancers (BC) are non-muscle invasive when first diagnosed and are usually treated by transurethral tumor resection. But 50-80% of patients experience cancer recurrence. Agents for prevention of primary BC have yet to be identified. Existing prophylactics against BC recurrence, e.g., Bacillus Calmette-Guerin (BCG), have limited efficacy and utility; they engender significant side effects and require urethral catheterization. Many cruciferous vegetables, rich sources of isothiocyanates (ITCs), are commonly consumed by humans. Many ITCs possess promising chemopreventive activities against BC and its recurrence. Moreover, orally ingested ITCs are selectively delivered to bladder via urinary excretion. This review is focused on urinary delivery of ITCs to the bladder, their cellular uptake, their chemopreventive activities in preclinical and epidemiological studies that are particularly relevant to prevention of BC recurrence and progression, and their chemopreventive mechanisms in BC cells and tissues.

Allyl isothiocyanate depletes glutathione and upregulates expression of glutathione S-transferases in Arabidopsis thaliana

Allyl isothiocyanate (AITC) is a phytochemical associated with plant defense in plants from the Brassicaceae family. AITC has long been recognized as a countermeasure against external threats, but recent reports suggest that AITC is also involved in the onset of defense-related mechanisms such as the regulation of stomatal aperture. However, the underlying cellular modes of action in plants remain scarcely investigated. Here we report evidence of an AITC-induced depletion of glutathione (GSH) and the effect on gene expression of the detoxification enzyme family glutathione S-transferases (GSTs) in Arabidopsis thaliana. Treatment of A. thaliana wild-type with AITC resulted in a time- and dose-dependent depletion of cellular GSH. AITC-exposure of mutant lines vtc1 and pad2-1 with elevated and reduced GSH-levels, displayed enhanced and decreased AITC-tolerance, respectively. AITC-exposure also led to increased ROS-levels in the roots and loss of chlorophyll which are symptoms of oxidative stress. Following exposure to AITC, we found that GSH rapidly recovered to the same level as in the control plant, suggesting an effective route for replenishment of GSH or a rapid detoxification of AITC. Transcriptional analysis of genes encoding GSTs showed an upregulation in response to AITC. These findings demonstrate cellular effects by AITC involving a reversible depletion of the GSH-pool, induced oxidative stress, and elevated expression of GST-encoding genes.

Nuclear factor-kappaB sensitizes to benzyl isothiocyanate-induced antiproliferation in p53-deficient colorectal cancer cells

Benzyl isothiocyanate (BITC), a dietary isothiocyanate derived from cruciferous vegetables, inhibits the proliferation of colorectal cancer cells, most of which overexpress β-catenin as a result of mutations in the genes for adenomatous polyposis coli or mutations in β-catenin itself. Because nuclear factor-κB (NF-κB) is a plausible target of BITC signaling in inflammatory cell models, we hypothesized that it is also involved in BITC-inhibited proliferation of colorectal cancer cells. siRNA-mediated knockdown of the NF-κB p65 subunit significantly decreased the BITC sensitivity of human colorectal cancer HT-29 cells with mutated p53 tumor suppressor protein. Treating HT-29 cells with BITC induced the phosphorylation of IκB kinase, IκB-α and p65, the degradation of IκB-α, the translocation of p65 to the nucleus and the upregulation of NF-κB transcriptional activity. BITC also decreased β-catenin binding to a positive cis element of the cyclin D1 promoter and thus inhibited β-catenin-dependent cyclin D1 transcription, possibly through a direct interaction between p65 and β-catenin. siRNA-mediated knockdown of p65 confirmed that p65 negatively affects cyclin D1 expression. On the other hand, when human colorectal cancer HCT-116 cells with wild-type p53 were treated with BITC, translocation of p65 to the nucleus was inhibited rather than enhanced. p53 knockout increased the BITC sensitivity of HCT-116 cells in a p65-dependent manner, suggesting that p53 negatively regulates p65-dependent effects. Together, these results identify BITC as a novel type of antiproliferative agent that regulates the NF-κB pathway in p53-deficient colorectal cancer cells.

Dietary Isothiocyanates Modify Mitochondrial Functions through Their Electrophilic Reaction

We found that both benzyl isothiocyanate (ITC) and phenyl ITC inhibited respiration in the mitochondria in an electrophilic reaction-dependent manner. ITC-induced mitochondrial swelling and cytochrome c release were prevented by cyclosporin A, indicating that they are mediated through the ITC moiety-dependent reaction to critical thiol groups for the opening of membrane permeability transition-dependent pores.

Molecular targets of isothiocyanates in cancer: recent advances

Cancer is a multistep process resulting in uncontrolled cell division. It results from aberrant signaling pathways that lead to uninhibited cell division and growth. Various recent epidemiological studies have indicated that consumption of cruciferous vegetables, such as garden cress, broccoli, etc., reduces the risk of cancer. Isothiocyanates (ITCs) have been identified as major active constituents of cruciferous vegetables. ITCs occur in plants as glucosinolate and can readily be derived by hydrolysis. Numerous mechanistic studies have demonstrated the anticancer effects of ITCs in various cancer types. ITCs suppress tumor growth by generating reactive oxygen species or by inducing cycle arrest leading to apoptosis. Based on the exciting outcomes of preclinical studies, few ITCs have advanced to the clinical phase. Available data from preclinical as well as available clinical studies suggest ITCs to be one of the promising anticancer agents available from natural sources. This is an up-to-date exhaustive review on the preventive and therapeutic effects of ITCs in cancer.

Insights into the mode of action of benzyl isothiocyanate on Campylobacter jejuni

Campylobacter jejuni is a widespread pathogen responsible for most of the food-borne gastrointestinal diseases in Europe. The use of natural antimicrobial molecules is a promising alternative to antibiotic treatments for pathogen control in the food industry. Isothiocyanates are natural antimicrobial compounds, which also display anticancer activity. Several studies described the chemoprotective effect of isothiocyanates on eukaryotic cells, but the antimicrobial mechanism is still poorly understood. We investigated the early cellular response of C. jejuni to benzyl isothiocyanate by both transcriptomic and physiological approaches. The transcriptomic response of C. jejuni to benzyl isothiocyanate showed upregulation of heat shock response genes and an impact on energy metabolism. Oxygen consumption was progressively impaired by benzyl isothiocyanate treatment, as revealed by high-resolution respirometry, while the ATP content increased soon after benzyl isothiocyanate exposition, which suggests a shift in the energy metabolism balance. Finally, benzyl isothiocyanate induced intracellular protein aggregation. These results indicate that benzyl isothiocyanate affects C. jejuni by targeting proteins, resulting in the disruption of major metabolic processes and eventually leading to cell death.

Dietary phytochemicals and cancer prevention: Nrf2 signaling, epigenetics, and cell death mechanisms in blocking cancer initiation and progression

Reactive metabolites from carcinogens and oxidative stress can drive genetic mutations, genomic instability, neoplastic transformation, and ultimately carcinogenesis. Numerous dietary phytochemicals in vegetables/fruits have been shown to possess cancer chemopreventive effects in both preclinical animal models and human epidemiological studies. These phytochemicals could prevent the initiation of carcinogenesis via either direct scavenging of reactive oxygen species/reactive nitrogen species (ROS/RNS) or, more importantly, the induction of cellular defense detoxifying/antioxidant enzymes. These defense enzymes mediated by Nrf2-antioxidative stress and anti-inflammatory signaling pathways can contribute to cellular protection against ROS/RNS and reactive metabolites of carcinogens. In addition, these compounds would kill initiated/transformed cancer cells in vitro and in in vivo xenografts via diverse anti-cancer mechanisms. These mechanisms include the activation of signaling kinases (e.g., JNK), caspases and the mitochondria damage/cytochrome c pathways. Phytochemicals may also have anti-cancer effects by inhibiting the IKK/NF-κB pathway, inhibiting STAT3, and causing cell cycle arrest. In addition, other mechanisms may include epigenetic alterations (e.g., inhibition of HDACs, miRNAs, and the modification of the CpG methylation of cancer-related genes). In this review, we will discuss: the current advances in the study of Nrf2 signaling; Nrf2-deficient tumor mouse models; the epigenetic control of Nrf2 in tumorigenesis and chemoprevention; Nrf2-mediated cancer chemoprevention by naturally occurring dietary phytochemicals; and the mutation or hyper-expression of the Nrf2-Keap1 signaling pathway in advanced tumor cells. The future development of dietary phytochemicals for chemoprevention must integrate in vitro signaling mechanisms, relevant biomarkers of human diseases, and combinations of different phytochemicals and/or non-toxic therapeutic drugs, including NSAIDs.

Phenylalkyl isoselenocyanates vs phenylalkyl isothiocyanates: thiol reactivity and its implications

Phenylalkyl isoselenocyanate (ISC) compounds were recently designed in our laboratory by incorporating the anticancer element selenium into a panel of phenylalkyl isothiocyanates (ITCs), known to have anticancer properties. A structural activity investigation was carried out to compare the ISC and ITC panels. Cell viability assay and Annexin V staining for apoptosis showed ISC compounds to be more potent in killing A549 lung adenocarcinoma cells. Both ITCs and ISCs were able to deplete reduced glutathione (GSH) in cells, ISCs more rapidly, but ITCs to a greater extent. ISC compounds had a higher rate of reaction to thiol (-SH) groups as determined by pseudo first order kinetics than the corresponding carbon chain length ITC. The equilibrium concentrations of the GSH and protein thiol conjugates did not differ significantly when comparing sulfur to selenium compounds of the same carbon chain length, and did follow the same trend of displaying decreasing reactivity with increasing carbon chain length for both ITCs and ISCs. Furthermore, only ITCs were able to induce cell cycle arrest, suggesting that protein targets inside the cell may differ for the S and Se panels. Finally, the panels were tested for their ability to redox cycle when reacted with GSH to form superoxide and other reactive oxygen species (ROS). ISC compounds showed a much greater ability to redox cycle than corresponding ITCs, and were able to induce higher levels of ROS in A549 cells. Also, the direct pro-apoptotic effects of ISCs and ITCs were inhibited by GSH and potentiated by depletion of intracellular GSH by buthionine sulfoximine. In conclusion, our studies suggest that the redox-cycling capabilities of ISCs and thus generation of higher levels of ROS may be contributing to the increased cytotoxicity of ISC compounds in A549 cells, compared to that of the corresponding ITCs.

Phenethyl isothiocyanate-induced cytoskeletal changes and cell death in lung cancer cells

Isothiocyanates are known for their anticarcinogenic and antitumor potential, however, the exact mechanism of their action has not been fully elucidated. The present study was designed to investigate and compare the effects of phenethyl isothiocyanate on cell morphology, the cytoskeleton and induction of cell death in human non-small cell lung cancer cell lines A549 and H1299 differing in p53 status. Cell viability tests (MTT assay, xCELLigence system) showed that PEITC exhibits lower cytotoxicity to A549 cells containing wild-type p53. The observed growth-inhibitory effect of PEITC was dose-dependent, but time-dependence was observed only at higher concentrations. The results of flow-cytometric and fluorescence-microscopic analyses indicate that PEITC induced disassembly of actin stress fibers and degradation of tubulin which, most likely, contributed to the induction of cell death. Although, 24-h incubation caused G2/M cell cycle arrest, the fraction of G2/M cells decreased in a dose- and time-dependent manner in favor of cells with sub-G1 DNA content. Further experiments (Annexin V staining, electron microscopic observations) confirmed that the apoptosis-inducing potency of PEITC is probably the main factor responsible for cell growth inhibition. However, PEITC treatment also resulted in the appearance of an increased proportion of H1299 cells exhibiting morphological features of mitotic catastrophe.

Development and application of a method for identification of isothiocyanate-targeted molecules in colon cancer cells

In this study, we have developed a novel method to identify isothiocyanate (ITC)-targeted molecules using two well-studied ITCs: benzyl ITC (BITC) and phenethyl ITC (PEITC). The principle of this method is based on identifying a pattern of differences between BITC and PEITC given that they show similar chemical and biological behaviors. For method validation, dithiothreitol-reduced bovine insulin as a model molecule was incubated with either BITC or PEITC, and digested peptides were analyzed by ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF-MS) and liquid chromatography quadrupole TOF-MS (LC-Q-TOF-MS). Three peptides-NYCN, FVNQHLCGSHLVE, and ALYLVCGE-were identified as being adducted with BITC or PEITC on their cysteine residues. Each set of peptides adducted with either BITC or PEITC showed retention times (RT(BITC)<RT(PEITC)) by reverse-phase column chromatography with a difference of molecular mass (Δ14.01565). On the basis of these findings, computational mathematical schemes were constructed to extract sets of MS ions satisfying the above criteria. Application of the developed method to an extract of ITC-treated human colon cancer HCT116 cells, thiocarbamoylation of cysteine residues of glutathione, and the N-terminal proline residues of PMFIVNTNVPR from macrophage migration inhibitory factor were successfully identified as one of the intracellular targets of ITCs. Moreover, the method also detected the thiocarbamoylated conjugates of ITCs with intracellular free cysteines and lysines.