Identification of potential protein targets of isothiocyanates by proteomics

Nutritional Sources and Anticancer Potential of Phenethyl Isothiocyanate: Molecular Mechanisms and Therapeutic Insights

Phenethyl isothiocyanate (PEITC), a compound derived from cruciferous vegetables, has garnered attention for its anticancer properties. This review synthesizes existing research on PEITC, focusing on its mechanisms of action in combatting cancer. PEITC has been found to be effective against various cancer types, such as breast, prostate, lung, colon, and pancreatic cancers. Its anticancer activities are mediated through several mechanisms, including the induction of apoptosis (programmed cell death), inhibition of cell proliferation, suppression of angiogenesis (formation of new blood vessels that feed tumors), and reduction of metastasis (spread of cancer cells to new areas). PEITC targets crucial cellular signaling pathways involved in cancer progression, notably the Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB), Protein Kinase B (Akt), and Mitogen-Activated Protein Kinase (MAPK) pathways. These findings suggest PEITC's potential as a therapeutic agent against cancer. However, further research is necessary to determine the optimal dosage, understand its bioavailability, and assess potential side effects. This will be crucial for developing PEITC-based treatments that are both effective and safe for clinical use in cancer therapy.

The Antimicrobial Effects of Myrosinase Hydrolysis Products Derived from Glucosinolates Isolated from Lepidium draba

Lepidium draba (hoary cress) is a perennial plant belonging to the Brassicaceae family that produces two dominant glucosinolates (GLSs): glucoraphanin (GRN) and sinalbin (SBN). They represent the stored form, which is converted upon the myrosinase (Myr) hydrolysis activity to active compounds, mainly isothiocyanates (ITCs) such as sulforaphane (SFN) or p-hydroxybenzyl isothiocyanate (pHBITC). Research on ITCs that have proven anticancer, antimicrobial, and chemoprotective properties is usually conducted with pure commercially available compounds. However, these are chemically reactive, making it difficult to use them directly for preventive purposes in dietary supplements. Efforts are currently being made to prepare dietary supplements enriched with GLS and/or Myr. In this study, we report a simple but efficient chromatographic procedure for the isolation and purification of GLSs from MeOH extract from hoary cress based on a combination of ion exchange and gel permeation chromatography on DEAE-Sephadex A-25 and Sephadex LH-20. To obtain the Myr required for efficient hydrolysis of GLSs into antibacterial ITCs, we developed a rapid method for its extraction from the seeds of Lepidium sativum (garden cress). The yields of GLSs were 22.9 ± 1.2 mg GRN (purity 96%) and 10.4 ± 1.1 mg SBN (purity 92%) from 1 g of dry plant material. Both purified GLSs were used as substrates for the Myr. Analysis of the composition of hydrolysis products (HPs) revealed differences in their hydrolysis rates and in the degree of conversion from GLSs to individual ITCs catalyzed by Myr. When GRNs were cleaved, SFNs were formed in an equimolar ratio, but the formation of pHBITCs was only half that of cleaved SBNs. The decrease in pHBITC content is due to its instability compared to SFN. While SFN is stable in aqueous media during the measurement, pHBITC undergoes non-enzymatic hydrolysis to p-hydroxybenzyl alcohol and thiocyanate ions. Testing of the antimicrobial effects of the HPs formed from GRN by Myr under premix or in situ conditions showed inhibition of the growth of model prokaryotic and eukaryotic microorganisms. This observation could serve as the jumping-off point for the design of a two-component mixture, based on purified GLSs and Myr that is, usable in food or the pharmaceutical industry in the future.

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

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

Cloning and expression of the mitochondrial cytochrome c oxidase subunit II gene in Sitophilus zeamais and interaction mechanism with allyl isothiocyanate

In the United States, allyl isothiocyanate (AITC) has been registered as an insecticide, bactericide, and nematicide. And it has been confirmed that AITC has significant insecticidal activities against four stored product pests including Sitophilus zeamais Mostchulky (Coleoptera: Curculionidae). This study aimed to verify the mechanism of action of AITC on cytochrome c oxidase core subunits II in S. zeamais. Enzyme - catalyzed reactions and Fourier transform infrared spectrometer (FTIR) analysis revealed that the expressed COX II proteins could competitively bind and inhibit the activity of COX II. Furthermore, molecular docking results showed that a sulfur atom of AITC could form a 2.9 Å hydrogen bond with Ile-30, having a binding energy of -2.46 kcal/mol.

Eukaryotic Expression of the Cytochrome c Oxidase Subunit I of Sitophilus zeamais and Its Interaction with Allyl Isothiocyanate

Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) is a destructive pest of stored grains around the world. Allyl isothiocyanate (AITC) was shown to have good bioactivity in the control of S. zeamais. In this study, the interaction of AITC on cytochrome c oxidase core subunits I (COX I) and their binding mechanism were determined using spectroscopic, isothermal titration calorimetry and molecular docking techniques. The results indicate the binding constant (Ka) of AITC and COX I was 6.742 × 103 L/mol. Analysis of spectroscopic revealed that the binding of COX I to reduced Cyt c induced conformational changes of reduced Cyt c, while AITC could competitively bind and inhibit the activity of the COX I protein. Moreover, molecular docking results suggested a sulfur atom in the AITC structure could form a hydrogen bond having a length of 3.3 Å with the Gly- 27 of COX I.

The Importance of Microorganisms for Sustainable Agriculture-A Review

In the face of climate change, progressive degradation of the environment, including agricultural land negatively affecting plant growth and development, endangers plant productivity. Seeking efficient and sustainable agricultural techniques to replace agricultural chemicals is one of the most important challenges nowadays. The use of plant growth-promoting microorganisms is among the most promising approaches; however, molecular mechanisms underneath plant-microbe interactions are still poorly understood. In this review, we summarized the knowledge on plant-microbe interactions, highlighting the role of microbial and plant proteins and metabolites in the formation of symbiotic relationships. This review covers rhizosphere and phyllosphere microbiomes, the role of root exudates in plant-microorganism interactions, the functioning of the plant's immune system during the plant-microorganism interactions. We also emphasized the possible role of the stringent response and the evolutionarily conserved mechanism during the established interaction between plants and microorganisms. As a case study, we discussed fungi belonging to the genus Trichoderma. Our review aims to summarize the existing knowledge about plant-microorganism interactions and to highlight molecular pathways that need further investigation.

Covalent Modification of Proteins by Plant-Derived Natural Products: Proteomic Approaches and Biological Impacts

Plant-derived natural products (NPs) with electrophilic functional groups engage various subsets of the proteome via covalent modification of nucleophilic cysteine residues. This electrophile-nucleophile interaction can change protein conformation, alter protein function, and modulate their biological action. The biological significance of these covalent protein modifications in health and disease is increasingly recognized. One way to understand covalent NP-protein interactions is to utilize traditional proteomics and modern mass spectrometry (MS)-based proteomic strategies. These strategies have proven effective in uncovering specific NP protein targets and are critical first steps that allow for a much deeper understanding of the ability of NPs to modulate cellular processes. Here, plant-derived NPs that covalently modify proteins are reviewed, the biological significance of these covalent modifications, and the different proteomic strategies that have been employed to study these NP-protein interactions.

Prospective evaluation of the lymph node proteome in dogs with multicentric lymphoma supplemented with sulforaphane

Background

Lymphoma (LSA) is a common malignancy in dogs. Epigenetic changes are linked to LSA pathogenesis and poor prognosis in humans, and LSA pathogenesis in dogs. Sulforaphane (SFN), an epigenetic‐targeting compound, has recently gained interest in relation to cancer prevention and therapy.

Objective

Examine the impact of oral supplementation with SFN on the lymph node proteome of dogs with multicentric LSA.

Animals

Seven client‐owned dogs with multicentric LSA.

Methods

Prospective, nonrandomized, noncontrolled study in treatment‐naïve dogs with intermediate or large cell multicentric LSA. Lymph node cell aspirates were obtained before and after 7 days of oral supplementation with SFN, and analyzed via label‐free mass spectrometry, immunoblots, and Gene Set Enrichment Analysis.

Results

There was no clinical response and no adverse events attributed to SFN. For individual dogs, the expression of up to 650 proteins changed by at least 2‐fold (range, 2‐100) after supplementation with SFN. When all dogs where analyzed together, 14 proteins were significantly downregulated, and 10 proteins were significantly upregulated after supplementation with SFN (P < .05). Proteins and gene sets impacted by SFN were commonly involved in immunity, response to oxidative stress, gene transcription, apoptosis, protein transport, maturation and ubiquitination.

Conclusions and Clinical Importance

Sulforaphane is associated with major changes in the proteome of neoplastic lymphocytes in dogs.

Chemical Aspects of Biological Activity of Isothiocyanates and Indoles, the Products of Glucosinolate Decomposition

There is growing evidence that cancer chemoprevention employing natural, bioactive compounds may halt or at least slow down the different stages of carcinogenesis. A particularly advantageous effect is attributed to derivatives of sulfur-organic phytochemicals, such as glucosinolates (GLs) synthesized mainly in Brassicaceae plant family. GLs are hydrolysed enzymatically to bioactive isothiocyanates (ITC) and indoles, which exhibit strong anti-inflammatory and anti-carcinogenic activity. Highly bioavailable electrophilic ITC are of particular interest, as they can react with nucleophilic groups of important biomolecules to form dithiocarbamates, thiocarbamates and thioureas. These modifications seem responsible for the chemopreventive activity, but also for genotoxicity and mutagenicity. It was documented that ITC can permanently bind to important biomolecules such as glutathione, cytoskeleton proteins, transcription factors NF-κB and Nrf2, thiol-disulfide oxidoreductases, proteasome proteins or heat shock proteins. Furthermore, ITC may also affect epigenetic regulation of gene expression, e.g. by inhibition of histone deacetylases. Some other derivatives of glucosinolates, especially indoles, are able to form covalent bonds with nucleobases in DNA, which may result in genotoxicity and mutagenicity. This article summarizes the current state of knowledge about glucosinolates and their degradation products in terms of possible interactions with reactive groups of cellular molecules.

Sulforaphane: Expected to Become a Novel Antitumor Compound

Natural products are becoming increasingly popular in a variety of traditional, complementary, and alternative systems due to their potency and slight side effects. Natural compounds have been shown to be effective against many human diseases, especially cancers. Sulforaphane (SFE) is a traditional Chinese herbal medicine. In recent years, an increasing number of studies have been conducted to evaluate the antitumor effect of SFE. The roles of SFE in cancers are mainly through the regulation of potential biomarkers to activate or inhibit related signaling pathways. SFE has exhibited promising inhibitory effects on breast cancer, lung cancer, liver cancer, and other malignant tumors. In this review, we summarized the reports on the activity and functional mechanisms of SFE in cancer treatment and explored the efficacy and toxicity of SFE.

Leucine zipper transcription factor-like 1 binds adaptor protein complex-1 and 2 and participates in trafficking of transferrin receptor 1

LZTFL1 participates in immune synapse formation, ciliogenesis, and the localization of ciliary proteins, and knockout of LZTFL1 induces abnormal distribution of heterotetrameric adaptor protein complex-1 (AP-1) in the Lztfl1-knockout mouse photoreceptor cells, suggesting that LZTFL1 is involved in intracellular transport. Here, we demonstrate that in vitro LZTFL1 directly binds to AP-1 and AP-2 and coimmunoprecipitates AP-1 and AP-2 from cell lysates. DxxFxxLxxxR motif of LZTFL1 is essential for these bindings, suggesting LZTFL1 has roles in AP-1 and AP-2-mediated protein trafficking. Since AP-1 and AP-2 are known to be involved in transferrin receptor 1 (TfR1) trafficking, the effect of LZTFL1 on TfR1 recycling was analyzed. TfR1, AP-1 and LZTFL1 from cell lysates could be coimmunoprecipitated. However, pull-down results indicate there is no direct interaction between TfR1 and LZTFL1, suggesting that LZTFL1 interaction with TfR1 is indirect through AP-1. We report the colocalization of LZTFL1 and AP-1, AP-1 and TfR1 as well as LZTFL1 and TfR1 in the perinuclear region (PNR) and the cytoplasm, suggesting a potential complex between LZTFL1, AP-1 and TfR1. The results from the disruption of adaptin recruitment with brefeldin A treatment suggested ADP-ribosylation factor-dependent localization of LZFL1 and AP-1 in the PNR. Knockdown of AP-1 reduces the level of LZTFL1 in the PNR, suggesting that AP-1 plays a role in LZTFL1 trafficking. Knockout of LZTFL1 reduces the cell surface level and the rate of internalization of TfR1, leading to a decrease of transferrin uptake, efflux, and internalization. However, knockout of LZTFL1 did not affect the cell surface levels of epidermal growth factor receptor and cation-independent mannose 6-phosphate receptor, indicating that LZTFL1 specifically regulates the cell surface level of TfR1. These data support a novel role of LZTFL1 in regulating the cell surface TfR1 level by interacting with AP-1 and AP-2.

Bioinformatics Analysis of Potential Key Genes in Trastuzumab-Resistant Gastric Cancer

Background

This study was performed to identify genes related to acquired trastuzumab resistance in gastric cancer (GC) and to analyze their prognostic value.

Methods

The gene expression profile GSE77346 was downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were obtained by using GEO2R. Functional and pathway enrichment was analyzed by using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Search Tool for the Retrieval of Interacting Genes (STRING), Cytoscape, and MCODE were then used to construct the protein-protein interaction (PPI) network and identify hub genes. Finally, the relationship between hub genes and overall survival (OS) was analyzed by using the online Kaplan-Meier plotter tool.

Results

A total of 327 DEGs were screened and were mainly enriched in terms related to pathways in cancer, signaling pathways regulating stem cell pluripotency, HTLV-I infection, and ECM-receptor interactions. A PPI network was constructed, and 18 hub genes (including one upregulated gene and seventeen downregulated genes) were identified based on the degrees and MCODE scores of the PPI network. Finally, the expression of four hub genes (ERBB2, VIM, EGR1, and PSMB8) was found to be related to the prognosis of HER2-positive (HER2+) gastric cancer. However, the prognostic value of the other hub genes was controversial; interestingly, most of these genes were interferon- (IFN-) stimulated genes (ISGs).

Conclusions

Overall, we propose that the four hub genes may be potential targets in trastuzumab-resistant gastric cancer and that ISGs may play a key role in promoting trastuzumab resistance in GC.

Various modes of action of dietary phytochemicals, sulforaphane and phenethyl isothiocyanate, on pathogenic bacteria

Isothiocyanates (ITCs) derived from cruciferous plants reveal antibacterial activity, although detailed mechanism is not fully elucidated. Recently it has been reported that ITCs induce the stringent response in Escherichia coli strains. The aim of this work was to determine whether two isothiocyanates, sulforaphane (SFN) and phenethyl isothiocyanate (PEITC), similarly as in E. coli induce stringent response in Bacillus subtilis, model Gram(+) bacterium, and test their potency against a panel of clinical isolates belonging to Gram(+) or Gram(-) groups. Minimal inhibitory concentrations were determined as well as effect of ITCs on membranes integrity, synthesis of DNA, RNA and stringent response alarmones was assessed. SFN and PEITC are effective against B. subtilis and bacterial isolates, namely E. coli, K. pneumonia, S. aureus, S. epidermidis and E. faecalis. Interestingly, in B. subtilis and E. faecalis the inhibition of growth and nucleic acids synthesis is independent of ppGpp accumulation. In bacteria, which do not induce the stringent response in the presence of ITCs, membrane integrity disruption is observed. Thus, ITCs are effective against different pathogenic bacteria and act by at least two mechanisms depending on bacteria species.

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.

Mechanism of selective anticancer activity of isothiocyanates relies on differences in DNA damage repair between cancer and healthy cells

Purpose

Isothiocyanates (ITCs) are compounds derived from Brassica plants with documented anticancer activity. Molecular mechanisms of their selective activity against cancer cells are still underexplored. In this work, the impact of ITC on DNA replication and damage was compared between PC-3 prostate cancer cells and HDFa normal fibroblasts as well as PNT2 prostate epithelial cells.

Methods

Cells were treated with sulforaphane or phenethyl isothiocyanate. [³H]thymidine incorporation and the level of histone γH2A.X were estimated as indicators of DNA replication and double-strand breaks (DSB), respectively. Levels of HDAC3, CtIP, and p-RPA were investigated by immunoblotting. Comet assay was performed to visualize DNA damage.

Results

ITCs inhibited DNA replication in all tested cell lines, and this activity was independent of reactive oxygen species of mitochondrial origin. It was followed by DSB which were more pronounced in cancer than noncancerous cells. This difference was independent of HDAC activity which was decreased in both cell lines when treated with ITCs. On the other hand, it correlated with faster removal of DSB, and thus, transient activation of repair proteins in normal cells, while in PC-3 prostate cancer, cell DNA repair was significantly less effective.

Conclusion

DNA damage induced by ITCs is a consequence of the block in DNA replication which is observed in both, cancer and normal cells. Selective antiproliferative activity of ITCs towards cancer cells results from less efficient DNA repair in cancer cells relative to normal cells.

Targeting allosteric site of AKT by 5,7-dimethoxy-1,4-phenanthrenequinone suppresses neutrophilic inflammation

BACKGROUND

Acute lung injury (ALI) is a severe life-threatening inflammatory disease. Neutrophil activation is a major pathogenic factor in ALI. Protein kinase B (PKB)/AKT regulates diverse cellular responses, but the significance in neutrophilic inflammation and ALI remains unknown.

METHODS

Human neutrophils and neutrophil-like differentiated HL-60 (dHL-60) cells were used to examine the anti-inflammatory effects of 5,7-dimethoxy-1,4-phenanthrenequinone (CLLV-1). The therapeutic potential of CLLV-1 was determined in a mouse model of lipopolysaccharide (LPS)-induced ALI.

FINDINGS

CLLV-1 inhibited respiratory burst, degranulation, adhesion, and chemotaxis in human neutrophils and dHL-60 cells. CLLV-1 inhibited the phosphorylation of AKT (Thr308 and Ser473), but not of ERK, JNK, or p38. Furthermore, CLLV-1 blocked AKT activity and covalently reacted with AKT Cys310 in vitro. The AKT_309-313 peptide-CLLV-1 adducts were determined by NMR or mass spectrometry assay. The alkylation agent-conjugated AKT (reduced form) level was also inhibited by CLLV-1. Significantly, CLLV-1 ameliorated LPS-induced ALI, neutrophil infiltration, and AKT activation in mice.

INTERPRETATION

Our results identify CLLV-1 as a covalent allosteric AKT inhibitor by targeting AKT Cys310. CLLV-1 shows potent anti-inflammatory activity in human neutrophils and LPS-induced mouse ALI. Our findings provide a mechanistic framework for redox modification of AKT that may serve as a novel pharmacological target to alleviate neutrophilic inflammation.

Phenethyl Isothiocyanate, a Dual Activator of Transcription Factors NRF2 and HSF1

Cruciferous vegetables are rich sources of glucosinolates which are the biogenic precursor molecules of isothiocyanates (ITCs). The relationship between the consumption of cruciferous vegetables and chemoprotection has been widely documented in epidemiological studies. Phenethyl isothiocyanate (PEITC) occurs as its glucosinolate precursor gluconasturtiin in the cruciferous vegetable watercress (Nasturtium officinale). PEITC has multiple biological effects, including activation of cytoprotective pathways, such as those mediated by the transcription factor nuclear factor erythroid 2 p45-related factor 2 (NRF2) and the transcription factor heat shock factor 1 (HSF1), and can cause changes in the epigenome. However, at high concentrations, PEITC leads to accumulation of reactive oxygen species and cytoskeletal changes, resulting in cytotoxicity. Underlying these activities is the sulfhydryl reactivity of PEITC with cysteine residues in its protein targets. This chemical reactivity highlights the critical importance of the dose of PEITC for achieving on-target selectivity, which should be carefully considered in the design of future clinical trials.

In Vitro Determination of Protein Conjugates in Human Cells by LC-ESI-MS/MS after Benzyl Isothiocyanate Exposure

Glucosinolates and their breakdown products, especially isothiocyanates (ITCs), are hypothesized to exert a broad range of bioactivities. However, physiological mechanisms are not yet completely understood. In this study, formation of protein conjugates after incubation with benzyl isothiocyanate (BITC) was investigated in vitro. A survey of protein conjugates was done by determining BITC cysteine and lysine amino acid conjugates after protein digestion. Therefore, a liquid chromatography-tandem mass spectrometry (LC-ESI-MS/MS) method was developed and validated. Stability studies showed that cysteine conjugates are not stable under alkaline conditions, and lysine conjugates did not show any correlation to pH values, although stability increased at low temperatures. Lysine conjugates were the preferred form of protein conjugates, and longer BITC exposure times led to higher amounts. Knowledge about the reaction sites of ITCs in eukaryotic cells may help to understand the mode of action of ITCs leading to health promoting as well as toxicological effects in humans.

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.

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

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

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.

Molecular cloning and expression analysis of cytochrome c oxidase subunit II from Sitophilus zeamais

Cytochrome c oxidase subunit II (COX II) containing a dual core CuA active site is one of the core subunits of mitochondrial Cytochrome c oxidase (Cco), which plays a significant role in the physiological process. In this report, the full-length cDNA of COXII gene was cloned from Sitophilus zeamais, which had an open reading frame (ORF) of 684 bp encoding 227 amino acids residues. The predicted COXII protein had a molecular mass of 26.2 kDa with pI value of 6.37. multiple sequence alignment and phylogenetic analysis indicated that Sitophilus zeamais COXII had high sequence identity with the COXII of other insect species. The gene was subcloned into the expression vector pET-32a, and induced by isopropyl β-d-thiogalactopyranoside (IPTG) in E. coli Transetta (DE3) expression system. Finally the recombinant COXII with 6-His tag was purified using affinity chromatography with Ni(2+)-NTA agarose. Western Blotting (WB) showed the recombinant protein was about 44 kD, and the concentration of fusion protein was 50 μg/mL. UV-spectrophotometer and infrared spectrometer analysis showed that recombinant COXII could catalyze the oxidation of substrate Cytochrome C (Cyt c), and influenced by allyl isothiocyanate (AITC). By using molecular docking method, It was found that a sulfur atom of AITC structure could form a length of 2.9 Å hydrogen bond with Leu-31. These results suggested that tag-free COXII was functional and one of the action sites of AITC, which will be helpful to carry out a point mutation in binding sites for the future research.

The potential role of some phytochemicals in recognition of mitochondrial damage-associated molecular patterns

Mitochondria are the source of damage-associated molecular patterns (DAMPs). DAMPs modulate responses to stress and trauma in animals, influencing the onset of many diseases. Dietary phytochemicals, which target various cellular molecules, are potential modulators of immunological status. In this review the existence of the possible impact of some plant-derived compounds with proven anti-cancer and anti-inflammatory properties (isothiocyanates and curcumin) on DAMPs recognition is highlighted. Special consideration is given to the mtDNA recognizing Toll-like receptor 9 and formyl peptide receptors. In the context of the phytochemicals action, the role of these receptors in epithelial homeostasis is also discussed.

Isothiocyanates as effective agents against enterohemorrhagic Escherichia coli: insight to the mode of action

Production of Shiga toxins by enterohemorrhagic Escherichia coli (EHEC) which is responsible for the pathogenicity of these strains, is strictly correlated with induction of lambdoid bacteriophages present in the host's genome, replication of phage DNA and expression of stx genes. Antibiotic treatment of EHEC infection may lead to induction of prophage into a lytic development, thus increasing the risk of severe complications. This, together with the spread of multi-drug resistance, increases the need for novel antimicrobial agents. We report here that isothiocyanates (ITC), plant secondary metabolites, such as sulforaphane (SFN), allyl isothiocyanate (AITC), benzyl isothiocynanate (BITC), phenyl isothiocyanate (PITC) and isopropyl isothiocyanate (IPRITC), inhibit bacterial growth and lytic development of stx-harboring prophages. The mechanism underlying the antimicrobial effect of ITCs involves the induction of global bacterial stress regulatory system, the stringent response. Its alarmone, guanosine penta/tetraphosphate ((p)ppGpp) affects major cellular processes, including nucleic acids synthesis, which leads to the efficient inhibition of both, prophage induction and toxin synthesis, abolishing in this way EHEC virulence for human and simian cells. Thus, ITCs could be considered as potential therapeutic agents in EHEC infections.

Comparative studies on mitochondrial electron transport chain complexes of Sitophilus zeamais treated with allyl isothiocyanate and calcium phosphide

With Sitophilus zeamais as the target organism, the present study for the first time attempted to elucidate the comparative effects between allyl isothiocyanate (AITC) and calcium phosphide (Ca3P2), exposure on mitochondrial electron transport chain (ETC.) complex I & IV and their downstream effects on enzymes relevant to reactive oxygen species (ROS). In vivo, both AITC and Ca3P2 inhibited complex I and IV with similar downstream effects. In contrast with Ca3P2, the inhibition of complex I caused by AITC was dependent on time and dose. In vitro, AITC inhibited complex IV more significantly than complex I. These results indicate that mitochondrial complex IV is the primary target of AITC, and that complex I is another potential target.

Allyl Isothiocyanate Inhibits Actin-Dependent Intracellular Transport in Arabidopsis thaliana

Volatile allyl isothiocyanate (AITC) derives from the biodegradation of the glucosinolate sinigrin and has been associated with growth inhibition in several plants, including the model plant Arabidopsis thaliana. However, the underlying cellular mechanisms of this feature remain scarcely investigated in plants. In this study, we present evidence of an AITC-induced inhibition of actin-dependent intracellular transport in A. thaliana. A transgenic line of A. thaliana expressing yellow fluorescent protein (YFP)-tagged actin filaments was used to show attenuation of actin filament movement by AITC. This appeared gradually in a time- and dose-dependent manner and resulted in actin filaments appearing close to static. Further, we employed four transgenic lines with YFP-fusion proteins labeling the Golgi apparatus, endoplasmic reticulum (ER), vacuoles and peroxisomes to demonstrate an AITC-induced inhibition of actin-dependent intracellular transport of or, in these structures, consistent with the decline in actin filament movement. Furthermore, the morphologies of actin filaments, ER and vacuoles appeared aberrant following AITC-exposure. However, AITC-treated seedlings of all transgenic lines tested displayed morphologies and intracellular movements similar to that of the corresponding untreated and control-treated plants, following overnight incubation in an AITC-absent environment, indicating that AITC-induced decline in actin-related movements is a reversible process. These findings provide novel insights into the cellular events in plant cells following exposure to AITC, which may further expose clues to the physiological significance of the glucosinolate-myrosinase system.

Inactivation of protein tyrosine phosphatases by dietary isothiocyanates

Isothiocyanates are bioactive dietary phytochemicals that react readily with protein thiol groups. We find that isothiocyanates are time-dependent inactivators of cysteine-dependent protein tyrosine phosphatases (PTPs). Rate constants for the inactivation of PTP1B and SHP-2 by allyl isothiocyanate and sulforaphane range from 2 to 16 M(-1)s(-1). Results in the context of PTP1B are consistent with a mechanism involving covalent, yet reversible, modification of the enzyme's active site cysteine residue.

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.

Insights into the binding sites of sulforaphane on insulin studied by electrospray ionization mass spectrometry

RATIONALE

Sulforaphane (SFN) is a natural isothiocyanate, known to reduce the risk of cancer and also aortic damage and diabetic cardiomyopathy induced by type 2 diabetes, etc. A more detailed knowledge on the direct interaction of SFN with insulin and its binding sites is necessary for better understanding the role of SFN on diabetes.

METHODS

Liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) and in-source fragmentation experiments were performed on a Thermo Exactive orbitrap mass spectrometer. The solution of insulin and SFN was incubated and analyzed by mass spectrometry. Isotopic distribution pattern, accurate mass values and theoretical product ions were used to analyze the mass spectrometry data. The nature of binding of SFN and its binding sites with insulin were evaluated by LC/MS data.

RESULTS

ESI-MS analysis of the incubated solution of insulin and SFN showed 1:1 and 1:2 complexes of [Insulin-SFN]. LC/MS analysis revealed that the [Insulin+SFN] complexes were due to covalent binding of SFN at two different sites. The in-source fragmentation experiments revealed that the SFN is binding to the NH2 groups of N-terminal amino acids of A and B chains of insulin. Further study of SFN with insulin reduced with dithiothreitol (DTT) showed exclusive modification of cysteines with SFN.

CONCLUSIONS

The interaction of SFN was studied with insulin using ESI-MS. SFN is found to bind covalently with the free NH2 group of the N-terminal of the A and B chains of insulin. However, when insulin is reduced SFN preferably binds to SH groups of cysteines. Hence, the present study helps in the understanding of the binding sites of SFN on insulin.

The glucosinolate metabolite 1-methoxy-3-indolylmethyl alcohol induces a gene expression profile in mouse liver similar to the expression signature caused by known genotoxic hepatocarcinogens

SCOPE

Breakdown products of certain glucosinolates induce detoxifying enzymes and demonstrate preventive activities against chemically induced tumourigenesis in animal models. However, other breakdown products are genotoxic. 1-Methoxy-3-indolylmethyl alcohol (1-MIM-OH) is mutagenic in bacterial and mammalian cells upon activation by sulphotransferases and forms DNA adducts in mouse tissues. This effect is enhanced in mice transgenic for human sulphotransferases 1A1/2 (FVB/N-hSULT1A1/2). Therefore, we explored gene expression changes induced by 1-MIM-OH in mouse liver.

METHODS AND RESULTS

FVB/N-hSULT1A1/2 mice were orally treated with 1-MIM-OH for 21 or 90 days, leading to high levels of hepatic 1-MIM-DNA adducts. Genome-wide expression analyses demonstrated no influence on detoxifying enzymes, but up-regulation of many mediators of the tumour suppressor p53 and down-regulation of Fhit and other long genes. While this p53 response might indicate protection, it was unable to prevent the accumulation of DNA adducts. However, various epidemiological studies reported inverse associations between the intake of cruciferous vegetables and cancer. This association may be due to the presence of other glucosinolates with tumour-preventing influences possibly outweighing adverse effects of some metabolites.

CONCLUSION

1-MIM-OH is a genotoxic substance inducing a gene expression profile similar to the expression signature caused by known genotoxic hepatocarcinogens.

Disintegration of microtubules in Arabidopsis thaliana and bladder cancer cells by isothiocyanates

Isothiocyanates (ITCs) from biodegradation of glucosinolates comprise a group of electrophiles associated with growth-inhibitory effects in plant- and mammalian cells. The underlying modes of action of this feature are not fully understood. Clarifying this has involved mammalian cancer cells due to ITCs' chemopreventive potential. The binding of ITCs to tubulins has been reported as a mechanism by which ITCs induce cell cycle arrest and apoptosis. In the present study we demonstrate that ITCs disrupt microtubules in Arabidopsis thaliana contributing to the observed inhibited growth phenotype. We also confirmed this in rat bladder cancer cells (AY-27) suggesting that cells from plant and animals share mechanisms by which ITCs affect growth. Exposure of A. thaliana to vapor-phase of allyl ITC (AITC) inhibited growth and induced a concurrent bleaching of leaves in a dose-dependent manner. Transcriptional analysis was used to show an upregulation of heat shock-genes upon AITC-treatment. Transgenic A. thaliana expressing GFP-marked α-tubulin was employed to show a time- and dose-dependent disintegration of microtubules by AITC. Treatment of AY-27 with ITCs resulted in a time- and dose-dependent decrease of cell proliferation and G2/M-arrest. AY-27 transiently transfected to express GFP-tagged α-tubulin were treated with ITCs resulting in a loss of microtubular filaments and the subsequent formation of apoptotic bodies. In conclusion, our data demonstrate an ITC-induced mechanism leading to growth inhibition in A. thaliana and rat bladder cancer cells, and expose clues to the mechanisms underlying the physiological role of glucosinolates in vivo.

CLL2-1, a chemical derivative of orchid 1,4-phenanthrenequinones, inhibits human platelet aggregation through thiol modification of calcium-diacylglycerol guanine nucleotide exchange factor-I (CalDAG-GEFI)

CalDAG-GEFI is a guanine nucleotide exchange factor, which actives small GTPase Rap1 and plays an important role in platelet aggregation. Our previous study has shown that CalDAG-GEFI contains redox-sensitive thiols, and its function can be inhibited by thiol modification. In the present study, the effect of CLL2-1, a 1,4-phenanthrenequinone, on CalDAG-GEFI and platelet functions was investigated. In human platelets, CLL2-1 prevented platelet aggregation caused by various stimulators. Flow cytometric analysis revealed that CLL2-1 inhibited GPIIb/IIIa activation and P-selectin secretion. Moreover, CLL2-1 prevented Rap1 activation caused by thrombin, the Ca(2+) ionophore A23187, and the diacylglycerol mimetic phorbol 12-myristate 13-acetate, while only slightly inhibited thrombin-induced increases in [Ca(2+)]i and did not inhibit protein kinase C activation. Western blots after reducing SDS-PAGE showed that treatment of either platelets or platelet lysates with CLL2-1 led to a decrease of monomeric CalDAG-GEFI and appearance of cross-linked oligomers of CalDAG-GEFI, and these effects were inhibited by pretreatment of platelets or lysates with thiol reducing agents prior to the addition of CLL2-1, indicating thiol modification of CalDAG-GEFI by CLL2-1. Furthermore, the thiol reducing agents also prevented the inhibitory effect of CLL2-1 on Rap1 activation, GPIIb/IIIa activation, and platelet aggregation. In CalDAG-GEFI-overexpressing human embryonic kidney 293T cells, CLL2-1 also inhibited CalDAG-GEFI-mediated Rap1 activation. Taken together, our results suggest that the antiplatelet effect of CLL2-1 is due to, at least in part, inhibition of CalDAG-GEFI-mediated Rap1 activation, and provide the basis for development of novel antiplatelet drugs.

Sulforaphane interaction with amyloid beta 1-40 peptide studied by electrospray ionization mass spectrometry

RATIONALE

Aggregation of amyloid beta 1-40 (Aβ) in the brain causes Alzheimer's disease (AD) and several small molecules are known to inhibit the aggregation process. Sulforaphane (SFN) is a natural isothiocyanate which is known to prevent various neurodegenerative processes. However, its interaction with Aβ is yet to be explored. Such studies could provide new mechanistic insights for its neuroprotective properties.

METHODS

Liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) and in-source fragmentation experiments were performed on an Orbitrap mass spectrometer. The solution of Aβ and SFN was incubated and analyzed by mass spectrometry. Isotopic distribution patterns, accurate mass values and theoretical product ions were used to analyze the mass spectrometry data. The nature of binding of SFN and its binding sites with Aβ were evaluated by LC/MS and trypsin digestion experiments.

RESULTS

ESI-MS analysis of the incubated solution of Aβ and SFN showed a 1:1 complex of [Aβ+SFN]. LC/MS analysis revealed that the solution contains three different [Aβ+SFN] complexes due to covalent binding of SFN to Aβ at three different sites. The in-source fragmentation experiments revealed that SFN is binding to free NH(2) groups (N-terminal amino acid and lysines) in Aβ. Trypsin digestion experiments further confirmed the SFN binding sites in Aβ.

CONCLUSIONS

The interaction of SFN, an anticancer agent, with Aβ was studied using ESI-MS. SFN is found to bind covalently and specifically with the free NH(2) group of N-terminal aspartic acid and the ε-amino group of lysine at positions 16 and 28. Aggregation assay studies showed a lesser inclination of Aβ to aggregate when SFN is present. Hence the present study helps in understanding the mechanism of the action of SFN on the Aβ peptide.

Phenethyl isothiocyanate induces DNA damage-associated G2/M arrest and subsequent apoptosis in oral cancer cells with varying p53 mutations

Phenethyl isothiocyanate (PEITC) is a naturally occurring cruciferous vegetable-derived compound that inhibits cell growth and induces apoptosis in oral cancer cells. However, the exact mechanism of PEITC action has not been fully elucidated. This study investigated the molecular mechanism and anticancer potential of PEITC in oral squamous cell carcinoma (OSCC) cells with various p53 statuses. PEITC inhibited the growth of OC2, SCC4, and SCC25 cells (functional p53 mutants) in a dose-dependent manner with low toxicity to normal cells. Treatment with PEITC induced reactive oxygen species production, nitric oxide generation, and GSH depletion and triggered DNA damage response as evidenced by flow cytometry, 8-OHdG formation, and comet assay. Furthermore, the subsequent activation of ATM, Chk2, and p53 as well as the increased expression of downstream proteins p21 and Bax resulted in a G2/M phase arrest by inhibiting Cdc25C, Cdc2, and cyclin B1. The PEITC-induced apoptotic cell death, following a diminished mitochondrial transmembrane potential, reduced the expression of Bcl-2 and Mcl-1, released mitochondrial cytochrome c, and activated caspase 3 and PARP cleavage. The p53 inhibitor pifithrin-α and the antioxidants N-acetylcysteine and glutathione (GSH) protected the cells from PEITC-mediated apoptosis. However, mito-TEMPO, catalase, apocynin, and L-NAME did not prevent PEITC-induced cell death, suggesting that PEITC induced G2/M phase arrest and apoptosis in oral cancer cells via a GSH redox stress and oxidative DNA damage-induced ATM-Chk2-p53-related pathway. These results provide new insights into the critical roles of both GSH redox stress and p53 in the regulation of PEITC-induced G2/M cell cycle arrest and apoptosis in OSCCs.

Phenethyl isothiocyanate: a comprehensive review of anti-cancer mechanisms

The epidemiological evidence suggests a strong inverse relationship between dietary intake of cruciferous vegetables and the incidence of cancer. Among other constituents of cruciferous vegetables, isothiocyanates (ITC) are the main bioactive chemicals present. Phenethyl isothiocyanate (PEITC) is present as gluconasturtiin in many cruciferous vegetables with remarkable anti-cancer effects. PEITC is known to not only prevent the initiation phase of carcinogenesis process but also to inhibit the progression of tumorigenesis. PEITC targets multiple proteins to suppress various cancer-promoting mechanisms such as cell proliferation, progression and metastasis. Pre-clinical evidence suggests that combination of PEITC with conventional anti-cancer agents is also highly effective in improving overall efficacy. Based on accumulating evidence, PEITC appears to be a promising agent for cancer therapy and is already under clinical trials for leukemia and lung cancer. This is the first review which provides a comprehensive analysis of known targets and mechanisms along with a critical evaluation of PEITC as a future anti-cancer agent.

Covalent modification of cytoskeletal proteins in neuronal cells by tryptamine-4,5-dione

Serotonin, 5-hydroxytryptamine, is a systemic bioactive amine that acts in the gut and brain. As a substrate of myeloperoxidase in vitro, serotonin is oxidized to tryptamine-4,5-dione (TD), which is highly reactive with thiols. In this work, we successively prepared a monoclonal antibody to quinone-modified proteins and found that the antibody preferentially recognizes the TD–thiol adduct. Using the antibody, we observed that the chloride ion, the predominant physiological substrate for myeloperoxidase in vivo, is not competitive toward the enzyme catalyzed serotonin oxidation process, suggesting that serotonin is a plausible physiological substrate for the enzyme in vivo. Immunocytochemical analyses revealed that TD staining was observed in the cytosol of SH-SY5Y neuroblastoma cells while blot analyses showed that some cellular proteins were preferentially modified. Pull-down analyses confirmed that the cytoskeletal proteins tubulins, vimentin, and neurofilament-L were modified. When pure tubulins were exposed to micromolar levels of synthetic TD, self-polymerization was initially enhanced and then suppressed. These results suggest that serotonin oxidation by myeloperoxidase or the action of other oxidants could cause functional alteration of cellular proteins, which may be related to neurodegeneration processes or irritable bowel syndrome.

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Antibody to quinone-modified protein was established and characterized.

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Modification of protein by quinone was dependent on myeloperoxidase but independent of chloride ion concentration.

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We immunochemically found that cellular proteins were preferentially modified.

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Quinone modulated polymerization of tubulins in vitro.

Chemo-predictive assay for targeting cancer stem-like cells in patients affected by brain tumors

Administration of ineffective anticancer therapy is associated with unnecessary toxicity and development of resistant clones. Cancer stem-like cells (CSLCs) resist chemotherapy, thereby causing relapse of the disease. Thus, development of a test that identifies the most effective chemotherapy management offers great promise for individualized anticancer treatments. We have developed an ex vivo chemotherapy sensitivity assay (ChemoID), which measures the sensitivity of CSLCs as well as the bulk of tumor cells to a variety of chemotherapy agents. Two patients, a 21-year old male (patient 1) and a 5-month female (patient 2), affected by anaplastic WHO grade-III ependymoma were screened using the ChemoID assay. Patient 1 was found sensitive to the combination of irinotecan and bevacizumab, which resulted in a prolonged disease progression free period of 18 months. Following recurrence, the combination of various chemotherapy drugs was tested again with the ChemoID assay. We found that benzyl isothiocyanate (BITC) greatly increased the chemosensitivity of the ependymoma cells to the combination of irinotecan and bevacizumab. After patient 1 was treated for two months with irinotecan, bevacizumab and supplements of cruciferous vegetable extracts containing BITC, we observed over 50% tumoral regression in comparison with pre-ChemoID scan as evidenced by MRI. Patient 2 was found resistant to all treatments tested and following 6 cycles of vincristine, carboplatin, cyclophosphamide, etoposide, and cisplatin in various combinations, the tumor of this patient rapidly progressed and proton beam therapy was recommended. As expected animal studies conducted with patient derived xenografts treated with ChemoID screened drugs recapitulated the clinical observation. This assay demonstrates that patients with the same histological stage and grade of cancer may vary considerably in their clinical response, suggesting that ChemoID testing which measures the sensitivity of CSLCs as well as the bulk of tumor cells to a variety of chemotherapy agents could lead to more effective and personalized anticancer treatments in the future.

Notch2 activation is protective against anticancer effects of zerumbone in human breast cancer cells

We showed previously that zerumbone (ZER), a sesquiterpene isolated from subtropical ginger, inhibited in vitro (MCF-7 and MDA-MB-231cells) and in vivo (MDA-MB-231 cells) growth of human breast cancer cells in association with apoptosis induction. Here, we investigated the role of Notch receptors in anticancer effects of ZER (cell migration inhibition and apoptosis induction) using breast cancer cells. Western blotting was performed to determine protein expression changes. Effect of ZER on transcriptional activity of Notch was assessed by luciferase reporter assays. Transfection with small hairpin RNA or small interfering RNA was performed for knockdown of Notch2 or Presenilin-1 protein. Cell migration and apoptosis were quantitated by Boyden chamber assay and flow cytometry, respectively. Exposure of MDA-MB-231, MCF-7, and SUM159 cells to ZER resulted in increased cleavage of Notch2 in each cell line. On the other hand, levels of cleaved Notch1 and Notch4 proteins were decreased following ZER treatment. Increased cleavage of Notch2 in ZER-treated cells was accompanied by induction of Presenilin-1 protein and transcriptional activation of Notch. Inhibition of cell migration as well as apoptosis induction resulting from ZER exposure was significantly augmented by knockdown of Notch2 protein. ZER-mediated cleavage of Notch2 protein in MDA-MB-231 cells was markedly attenuated upon RNA interference of Presenilin-1. Knockdown of Presenilin-1 protein also resulted in escalation of ZER-induced apoptosis. The present study indicates that Notch2 activation by ZER inhibits its proapoptotic and anti-migratory response at least in breast cancer cells.

Evolution in an ancient detoxification pathway is coupled with a transition to herbivory in the drosophilidae

Chemically defended plant tissues present formidable barriers to herbivores. Although mechanisms to resist plant defenses have been identified in ancient herbivorous lineages, adaptations to overcome plant defenses during transitions to herbivory remain relatively unexplored. The fly genus Scaptomyza is nested within the genus Drosophila and includes species that feed on the living tissue of mustard plants (Brassicaceae), yet this lineage is derived from microbe-feeding ancestors. We found that mustard-feeding Scaptomyza species and microbe-feeding Drosophila melanogaster detoxify mustard oils, the primary chemical defenses in the Brassicaceae, using the widely conserved mercapturic acid pathway. This detoxification strategy differs from other specialist herbivores of mustard plants, which possess derived mechanisms to obviate mustard oil formation. To investigate whether mustard feeding is coupled with evolution in the mercapturic acid pathway, we profiled functional and molecular evolutionary changes in the enzyme glutathione S-transferase D1 (GSTD1), which catalyzes the first step of the mercapturic acid pathway and is induced by mustard defense products in Scaptomyza. GSTD1 acquired elevated activity against mustard oils in one mustard-feeding Scaptomyza species in which GstD1 was duplicated. Structural analysis and mutagenesis revealed that substitutions at conserved residues within and near the substrate-binding cleft account for most of this increase in activity against mustard oils. Functional evolution of GSTD1 was coupled with signatures of episodic positive selection in GstD1 after the evolution of herbivory. Overall, we found that preexisting functions of generalized detoxification systems, and their refinement by natural selection, could play a central role in the evolution of herbivory.

Cruciferous vegetable intake is inversely correlated with circulating levels of proinflammatory markers in women

BACKGROUND

Higher intakes of cruciferous vegetables or their constituents have been shown to lower inflammation in animal studies. However, evidence for this anti-inflammatory effect of cruciferous vegetable consumption in humans is scarce.

OBJECTIVE/DESIGN

In this cross-sectional analysis, we evaluated associations of vegetable intake with a panel of inflammatory and oxidative stress markers among 1,005 middle-aged Chinese women. Dietary intake of foods was assessed by a food frequency questionnaire.

RESULTS

Multivariable-adjusted circulating concentrations of tumor necrosis factor-α (TNF-α), interlukin-1β (IL-1β), and IL-6 were lower among women with higher intakes of cruciferous vegetables. The differences in concentrations of inflammatory biomarkers between extreme quintiles of cruciferous vegetable intake were 12.66% for TNF-α (Ptrend=0.01), 18.18% for IL-1β (Ptrend=0.02), and 24.68% for IL-6 (Ptrend=0.02). A similar, but less apparent, inverse association was found for intakes of all vegetables combined but not for noncruciferous vegetables. Levels of the urinary oxidative stress markers F2-isoprostanes and their major metabolite, 2,3-dinor-5,6-dihydro-15-F2t-IsoP, were not associated with intakes of cruciferous vegetables or all vegetables combined.

CONCLUSIONS

This study suggests that the previously observed health benefits of cruciferous vegetable consumption may be partly associated with the anti-inflammatory effects of these vegetables.

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.

Benzyl isothiocyanate inhibits HNSCC cell migration and invasion, and sensitizes HNSCC cells to cisplatin

Metastasis and chemoresistance represent two detrimental events that greatly hinder the outcome for those suffering with head and neck squamous cell carcinoma (HNSCC). Herein, we investigated benzyl isothiocyanate's (BITC) ability to inhibit HNSCC migration and invasion and enhance chemotherapy. Our data suggests that treatment with BITC 1) induced significant reductions in the viability of multiple HNSCC cell lines tested (HN12, HN8, and HN30) after 24 and 48 h, 2) decreased migration and invasion of the HN12 cells in a dose dependent manner, and 3) inhibited expression and altered localization of the epithelial-mesenchymal transition (EMT) marker, vimentin. We also observed that a pretreatment of BITC followed by cisplatin treatment 1) induced a greater decrease in HN12, HN30, and HN8 cell viability and total cell count than either treatment alone and 2) significantly increased apoptosis when compared to either treatment alone. Taken together these data suggest that BITC has the capacity to inhibit processes involved in metastasis and enhance the effectiveness of chemotherapy. Consequently, the results indicate that further investigation, including in vivo studies, are warranted.

A Click Chemistry Approach to Identify Protein Targets of Cancer Chemopreventive Phenethyl Isothiocyanate

Here we report the identification of protein targets of chemopreventive phenethyl isothiocyanate (PEITC) via "click" chemistry in the A549 human lung cancer cell line, using a novel alkyne-tagged PEITC which was also found to show potent in vitro anticancer activity.

Phenethyl isothiocyanate induces calcium mobilization and mitochondrial cell death pathway in cholangiocarcinoma KKU-M214 cells

Background

Phenethyl isothiocyanate (PEITC) is a cancer chemopreventive agent from cruciferous vegetables. Cholangiocarcinoma (CCA) is a chemo-resistant cancer with very poor prognosis. We evaluated the effects of PEITC on induction of apoptotic cell death in relation to cellular glutathione (GSH) and mitochondrial function of a CCA cell line, KKU-M214.

Methods

Cytotoxic effects of PEITC on a CCA cell line, KKU-M214, and a reference cell line, Chang cells were evaluated. To delineate mechanisms of cell death, the following parameters were measured; GSH and superoxide levels as the oxidative status parameters, apoptosis related proteins levels using Western blotting. Cellular free calcium level and mitochondrial transmembrane potential were also measured.

Results

PEITC induced apoptotic cell death of both KKU-M214 and Chang cells. After PEITC treatment, both cells showed decrease of Bcl-xl and increase of Bax levels. While KKU-M214 cells released AIF, Chang cells released cytochrome c, with subsequent activation of caspase 3 and 9, upon PEITC treatment. PEITC induced superoxide formation in both cells, although it seemed not play a role in cell death. PEITC caused GSH redox stress in different ways in two cell types, because N-acetylcysteine (NAC) prevented redox stress in Chang but not in KKU-M214 cells. The loss of mitochondrial transmembrane potential was induced by PEITC concurrent with GSH stress, but was not a primary cause of cell death. The rapid increase of free calcium level in cytosol was associated with cell death in both cell lines. These events were prevented by NAC in Chang cells, but not in KKU-M214 cells.

Conclusion

PEITC induced cell death KKU-M214 cells and Chang cells via increase of cellular calcium mobilization and activation of mitochondrial cell death pathway. The effects of PEITC on the redox stress was mediated via different ways in CCA and Chang cells because NAC could prevent redox stress in Chang cells, but not in KKU-M214 cells. The multiple effects of PEITC may be useful for the development of novel chemotherapy for CCA.

Pronounced toxicity differences between homobifunctional protein cross-linkers and analogous monofunctional electrophiles

Bifunctional electrophiles have been used in various chemopreventive, chemotherapeutic, and bioconjugate applications. Many of their effects in biological systems are traceable to their reactive properties, whereby they can modify nucleophilic sites in DNA, proteins, and other cellular molecules. Previously, we found that two different bifunctional electrophiles--diethyl acetylenedicarboxylate and divinyl sulfone--exhibited a strong enhancement of toxicity when compared with analogous monofunctional electrophiles in both human colorectal carcinoma cells and baker's yeast. Here, we have compared the toxicities for a broader panel of homobifunctional electrophiles bearing diverse electrophilic centers (e.g., isothiocyanate, isocyanate, epoxide, nitrogen mustard, and aldehyde groups) to their monofunctional analogues. Each bifunctional electrophile showed at least a 3-fold enhancement of toxicity over its monofunctional counterpart, although in most cases, the differences were even more pronounced. To explain their enhanced toxicity, we tested the ability of each bifunctional electrophile to cross-link recombinant yeast thioredoxin 2 (Trx2), a known intracellular target of electrophiles. The bifunctional electrophiles were capable of cross-linking Trx2 to itself in vitro and to other proteins in cells exposed to toxic concentrations. Moreover, most cross-linkers were preferentially reactive with thiols in these experiments. Collectively, our results indicate that thiol-reactive protein cross-linkers in general are much more potent cytotoxins than analogous monofunctional electrophiles, irrespective of the electrophilic group studied.