Diallyl Trisulfide Inhibits Phorbol Ester–Induced Tumor Promotion, Activation of AP-1, and Expression of COX-2 in Mouse Skin by Blocking JNK and Akt Signaling

Investigation of Antiproliferative Effects of Combinations of White and Black Garlic Extracts with 5-Fluorouracil (5-FU) on Caco-2 Colorectal Adenocarcinoma Cells

Garlic is rich in bioactive compounds that are effective against colon cancer cells. This study tests the antioxidant and antiproliferative effects of cold-extracted white and black garlic extracts. Black garlic extracted in water (SSU) exhibits the highest antioxidant activity, phenolic content, and flavonoid content, while black garlic extracted in ethanol (SET) shows the lowest values. Caspase-3 activity is notably higher in the white garlic extracted in methanol (BME), white garlic extracted in methanol combines with 5-FU, black garlic extracted in ethanol (SET), black garlic extracted in ethanol combines with 5-fluorouracil (5-FU), and 5-FU treatments compare to the control group (p > 0.05). BME+5-FU displays the highest caspase-8 activity (p < 0.05). A decrease in NF-κB levels is observed in the SET+5-FU group (p>0.05), while COX-2 activities decrease in the BME, SET+5-FU, SET, and 5-FU groups (p>0.05). Wound healing increases in the BME, BME+5-FU, SET+5-FU, and 5-FU groups (p < 0.05). In conclusion, aqueous black garlic extract may exhibit pro-oxidant activity despite its high antioxidant capacity. It is worth noting that exposure to heat-treated food and increased sugar content may lead to heightened inflammation and adverse health effects. This study is the first to combine garlic with chemo-preventive drugs like 5-FU in Caco-2 cells.

The Anticancer Effects of the Garlic Organosulfide Diallyl Trisulfide through the Attenuation of B[a]P-Induced Oxidative Stress, AhR Expression, and DNA Damage in Human Premalignant Breast Epithelial (MCF-10AT1) Cells

Benzo[a]pyrene (B[a]P) is the most characterized polycyclic aromatic hydrocarbon associated with breast cancer. Our lab previously reported that the organosulfur compound (OSC), diallyl trisulfide (DATS), chemoprevention mechanism works through the induction of cell cycle arrest and a reduction in oxidative stress and DNA damage in normal breast epithelial cells. We hypothesize that DATS will inhibit B[a]P-induced cancer initiation in premalignant breast epithelial (MCF-10AT1) cells. In this study, we evaluated the ability of DATS to attenuate B[a]P-induced neoplastic transformation in MCF-10AT1 cells by measuring biological endpoints such as proliferation, clonogenicity, reactive oxygen species (ROS) formation, and 8-hydroxy-2-deoxyguanosine (8-OHdG) DNA damage levels, as well as DNA repair and antioxidant proteins. The results indicate that B[a]P induced proliferation, clonogenic formation, ROS formation, and 8-OHdG levels, as well as increasing AhR, ARNT/HIF-1β, and CYP1A1 protein expression compared with the control in MCF-10AT1 cells. B[a]P/DATS's co-treatment (CoTx) inhibited cell proliferation, clonogenic formation, ROS formation, AhR protein expression, and 8-OHdG levels compared with B[a]P alone and attenuated all the above-mentioned B[a]P-induced changes in protein expression, causing a chemopreventive effect. This study demonstrates, for the first time, that DATS prevents premalignant breast cells from undergoing B[a]P-induced neoplastic transformation, thus providing more evidence for its chemopreventive effects in breast cancer.

Mechanism of active acetylcholinesterase inhibition by organic sulfanes in garlic: Non-covalent binding and covalent modifications

Numerous secondary metabolites in medicinal food homology plants such as Allium inhibit the activity of acetylcholinesterase (AChE), but the current understanding of the inhibition mechanism is limited. In this study, we employed ultrafiltration, spectroscopic, molecular docking, and matrix-assisted laser desorption ionization time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS) techniques to investigate the inhibition mechanism of AChE by garlic organic sulfanes, including diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS). The results of UV-spectrophotometry and ultrafiltration experiments showed the inhibition of AChE activity by DAS and DADS was reversible (competitive inhibition), but inhibition by DATS was irreversible. Molecular fluorescence and molecular docking indicated DAS and DADS changed the positions of key amino acids inside the catalytic cavity through hydrophobic interactions with AChE. By using MALDI-TOF-MS/MS, we found DATS irreversibly inhibited AChE activity by opening disulfide-bond switching of disulfide bond 1 (Cys-69 and Cys-96) and disulfide bond 2 (Cys-257 and Cys-272) in AChE, as well as by covalently modifying Cys-272 in disulfide bond 2 to generate AChE-SSA derivatives (strengthened switch). This study provides a basis for further exploration of natural AChE inhibitors using organic active substances in garlic and presents a hypothesis of U-shaped spring force arm effect based on the disulfide bond-switching reaction of DATS that can be used to evaluate the stability of disulfide bonds in proteins.

Involvement of adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1 in diallyl trisulfide-induced cytotoxicity in hepatocellular carcinoma cells

It has been demonstrated that APPL1 (adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1) is involved in the regulation of several growth-related signaling pathways and thus closely associated with the development and progression of some cancers. Diallyl trisulfide (DAT), a garlic-derived bioactive compound, exerts selective cytotoxicity to various human cancer cells through interfering with pro-survival signaling pathways. However, whether and how DAT affects survival of human hepatocellular carcinoma (HCC) cells remain unclear. Herein, we tested the hypothesis of the involvement of APPL1 in DAT-induced cytotoxicity in HCC HepG2 cells. We found that Lys 63 (K63)-linked polyubiquitination of APPL1 was significantly decreased whereas phosphorylation of APPL1 at serine residues remained unchanged in DAT-treated HepG2 cells. Compared with wild-type APPL1, overexpression of APPL1 K63R mutant dramatically increased cell apoptosis and mitigated cell survival, along with a reduction of phosphorylation of STAT3, Akt, and Erk1/2. In addition, DAT administration markedly reduced protein levels of intracellular TNF receptor-associated factor 6 (TRAF6). Genetic inhibition of TRAF6 decreased K63-linked polyubiquitination of APPL1. Moreover, the cytotoxicity impacts of DAT on HepG2 cells were greatly attenuated by overexpression of wild-type APPL1. Taken together, these results suggest that APPL1 polyubiquitination probably mediates the inhibitory effects of DAT on survival of HepG2 cells by modulating STAT3, Akt, and Erk1/2 pathways.

Effect of Garlic Organic Sulfides on Gene Expression Profiling in HepG2 Cells and Its Biological Function Analysis by Ingenuity Pathway Analysis System and Bio-Plex-Based Assays

Garlic organic sulfides are dietary bioactive components with multiple biofunctions to prevent chronic diseases/inflammation and promote human health. DADS (diallyl disulfide), DATS (diallyl trisulfide), and DTS (diallyl tetrasulfide) are typical organic sulfides with similar structures from garlic. However, the structure-activity relationship of garlic organic sulfides remained unknown. The aim of the present study was to investigate the effect of DADS, DATS, and DTS on the gene expression profiling of human hepatocellular carcinoma cells (HepG2) by application of microarray and specialized analysis software, GO, Bio-Plex-based cytokines assay and IPA and analyze their structure-activity relationship according to antioxidant, anti-inflammatory, and metabolic-related properties. According to the microarray data, with the increase of S atom in garlic organic sulfides, its biological activity was gradually enhanced. In the general catalog of GO, garlic organic sulfides mainly affect biological process, molecular function, and cellular component. RT-qPCR results indicated that the microarray data is trustworthy, and the structure-activity analysis data found that more sulfur atoms have more powerful properties; thus, microarray data of DTS was preceded to the subsequent IPA analysis. The results of IPA analysis showed that the top 5 signaling pathways and molecular functions were disturbed by DTS; the molecular functions with the highest scores affected by DTS are cancer, cell apoptosis, and cell proliferation, which imply that the occurrence or metabolism of these diseases is related to the differential expression of the above-mentioned related genes and the activation of signaling channels, and the core of the most significant molecular network is inflammation. Finally, the results found that the secretions of 6 cytokines in macrophages were significantly inhibited by DTS treatment. This is the first study that analyzed the structure-activity relationship of garlic organic sulfides, which will provide useful genetic information for its multi-biofunction and promote their clinical application in the near future.

Garlic (Allium sativum L.): Its Chemistry, Nutritional Composition, Toxicity and Anticancer Properties

The current review discuss the chemistry, nutritional composition, toxicity, and biological functions of garlic and its bioactive compounds against various types of cancers via different anticancer mechanisms. Several scientific documents were found in reliable literature and searched in databases viz Science Direct, PubMed, Web of Science, Scopus and Research Gate were carried out using keywords such as "garlic", "garlic bioactive compounds", "anticancer mechanisms of garlic", "nutritional composition of garlic", and others. Garlic contains several phytoconstituents with activities against cancer, and these compounds such as diallyl trisulfide (DATS), allicin, and diallyl disulfide (DADS), diallyl sulfide (DAS), and allyl mercaptan (AM). The influence of numerous garlic-derived products, phytochemicals, and nanoformulations on the liver, oral, prostate, breast, gastric, colorectal, skin, and pancreatic cancers has been studied. Based on our search, the bioactive molecules in garlic were found to inhibit the various phases of cancer. Moreover, the compounds in this plant also abrogate the peroxidation of lipids, activity of nitric oxide synthase, epidermal growth factor (EGF) receptor, nuclear factor-kappa B (NF-κB), protein kinase C, and regulate cell cycle and survival signaling cascades. Hence, garlic and its bioactive molecules exhibit the aforementioned mechanistic actions and thus, they could be used to inhibit the induction, development and progression of cancer. The review describes the nutritional Composition of garlic, its bioactive molecules, and nanoformulations against various types of cancers, as well as the potential for developing these agents as antitumor drugs.

Garlic constituents for cancer prevention and therapy: From phytochemistry to novel formulations

Garlic (Allium sativum L.) is one of the oldest plants cultivated for its dietary and medicinal values. This incredible plant is endowed with various pharmacological attributes, such as antimicrobial, antiarthritic, antithrombotic, antitumor, hypoglycemic, and hypolipidemic activities. Among the various beneficial pharmacological effects of garlic, the anticancer activity is presumably the most studied. The consumption of garlic provides strong protection against cancer risk. Taking into account the multi-targeted actions and absence of considerable toxicity, a few active metabolites of garlic are probably to play crucial roles in the killing of cancerous cells. Garlic contains several bioactive molecules with anticancer actions and these include diallyl trisulfide, allicin, diallyl disulfide, diallyl sulfide, and allyl mercaptan. The effects of various garlic-derived products, their phytoconstituents and nanoformulations have been evaluated against skin, prostate, ovarian, breast, gastric, colorectal, oral, liver, and pancreatic cancers. Garlic extract, its phytocompounds and their nanoformulations have been shown to inhibit the different stages of cancer, including initiation, promotion, and progression. Besides, these bioactive metabolites alter the peroxidation of lipid, activity of nitric oxide synthetase, nuclear factor-κB, epidermal growth factor receptor, and protein kinase C, cell cycle, and survival signaling. The current comprehensive review portrays the functions of garlic, its bioactive constituents and nanoformulations against several types of cancers and explores the possibility of developing these agents as anticancer pharmaceuticals.

Effects of sulphur-containing mineral water intake on oxidative status and markers for inflammation in healthy subjects

CONTEXT

Sulphurous mineral waters (SMW) have a wide range of applications. Sulphur content of mineral waters is considered as possible determinant for their anti-inflammatory or pro-inflammatory effects.

OBJECTIVE

To explore the healing properties of Varna basin mineral water by analysing possible antioxidative and anti-inflammatory effects.

MATERIALS AND METHODS

An intervention with Varna SMW intake was performed with healthy volunteers. Total thiols, total glutathione and its fractions, reactive oxygen metabolites, malondialdehyde, intracellular adhesion molecule (ICAM-1) and vascular cell adhesion molecule (VCAM-1) were measured. Expression of γ-gluthamyl-cysteinyl ligase (GCL) and sICAM-1 genes was also analysed.

RESULTS

A significantly increased total glutathione and total thiols were observed at the end of the intervention. GCL and sICAM-1 gene expressions were increased after the intervention.

CONCLUSION

SMW consumption improved redox status of the body. We suggested that these beneficial effects may be attributed to the established high levels of sulphur-containing compounds in Varna mineral water.

Health Benefits of Plant-Derived Sulfur Compounds, Glucosinolates, and Organosulfur Compounds

The broad spectrum of the mechanism of action of immune-boosting natural compounds as well as the complex nature of the food matrices make researching the health benefits of various food products a complicated task. Moreover, many routes are involved in the action of most natural compounds that lead to the inhibition of chronic inflammation, which results in a decrease in the ability to remove a pathogen asymptomatically and is connected to various pathological events, such as cancer. A number of cancers have been associated with inflammatory processes. The current review strives to answer the question of whether plant-derived sulfur compounds could be beneficial in cancer prevention and therapy. This review focuses on the two main sources of natural sulfur compounds: alliaceous and cruciferous vegetables. Through the presentation of scientific data which deal with the study of the chosen compounds in cancer (cell lines, animal models, and human studies), the discussion of food processing’s influence on immune-boosting food content is presented. Additionally, it is demonstrated that there is still a need to precisely demonstrate the bioavailability of sulfur-containing compounds from various types of functional food, since the inappropriate preparation of vegetables can significantly reduce the content of beneficial sulfur compounds. Additionally, there is an urgent need to carry out more epidemiological studies to reveal the benefits of several natural compounds in cancer prevention and therapy.

Garlic and its Active Compounds: A Potential Candidate in The Prevention of Cancer by Modulating Various Cell Signalling Pathways

BACKGROUND

Cancer is a multi-factorial disease including alterations in the cell signalling pathways. Currently, several drugs are in use to treat cancer but such drugs show negative side effects on normal cells and cause severe toxicity.

METHODS

The current research is mainly focused on medicinal plants with potential therapeutic efficacy in the treatment of cancer without any adverse effects on normal cells. In this regard, garlic and its active compounds including diallyl sulfide, diallyl trisulfide, ajoene, and allicin have been established to suppress the growth of cancer and killing of cancer cells.

RESULT

The review focuses on garlic and its active compounds chemopreventive effect through modulating various cell signalling pathways. Additionally, garlic and its active compound were established to induce cell cycle arrest at the G0/G1 phase and G2/M phases in cancer cells, increase the expression of tumor suppressor genes, inhibit the angiogenesis process, induction of apoptosis and modulation of various other genetic pathways.

CONCLUSION

This review sketches the diverse chemopreventive activities of garlic and their active ingredients in the management of cancer mainly focusing on cell signalling pathways.

Phytochemicals in Skin Cancer Prevention and Treatment: An Updated Review

Skin is the largest human organ, our protection against various environmental assaults and noxious agents. Accumulation of these stress events may lead to the formation of skin cancers, including both melanoma and non-melanoma skin cancers. Although modern targeted therapies have ameliorated the management of cutaneous malignancies, a safer, more affordable, and more effective strategy for chemoprevention and treatment is clearly needed for the improvement of skin cancer care. Phytochemicals are biologically active compounds derived from plants and herbal products. These agents appear to be beneficial in the battle against cancer as they exert anti-carcinogenic effects and are widely available, highly tolerated, and cost-effective. Evidence has indicated that the anti-carcinogenic properties of phytochemicals are due to their anti-oxidative, anti-inflammatory, anti-proliferative, and anti-angiogenic effects. In this review, we discuss the preventive potential, therapeutic effects, bioavailability, and structure–activity relationship of these selected phytochemicals for the management of skin cancers. The knowledge compiled here will provide clues for future investigations on novel oncostatic phytochemicals and additional anti-skin cancer mechanisms.

Dietary Bioactive Diallyl Trisulfide in Cancer Prevention and Treatment

Bioactive dietary agents have been shown to regulate multiple cancer hallmark pathways. Epidemiologic studies have linked consumption of Allium vegetables, such as garlic and onions, to decreased incidence of cancer. Diallyl trisulfide (DATS), a bioactive compound derived from Allium vegetables, has been investigated as an anti-cancer and chemopreventive agent. Preclinical studies provide ample evidence that DATS regulates multiple cancer hallmark pathways including cell cycle, apoptosis, angiogenesis, invasion, and metastasis. DATS has been shown to arrest cancer cells at multiple stages of the cell cycle with the G2/M arrest being the most widely reported. Additionally, increased pro-apoptotic capacity as a result of regulating intrinsic and extrinsic apoptotic pathway components has been widely reported following DATS treatment. Invasion, migration, and angiogenesis represent emerging targets of DATS and support its anti-cancer properties. This review summarizes DATS mechanisms of action as an anti-cancer and chemopreventive agent. These studies provide rationale for future investigation into its use as a cancer chemopreventive agent.

Toward Hydrogen Sulfide Based Therapeutics: Critical Drug Delivery and Developability Issues

Hydrogen sulfide (H₂ S), together with nitric oxide (NO) and carbon monoxide (CO), belongs to the gasotransmitter family and plays important roles in mammals as a signaling molecule. Many studies have also shown the various therapeutic effects of H₂ S, which include protection against myocardial ischemia injury, cytoprotection against oxidative stress, mediation of neurotransmission, inhibition of insulin signaling, regulation of inflammation, inhibition of the hypoxia-inducible pathway, and dilation of blood vessels. One major challenge in the development of H₂ S-based therapeutics is its delivery. In this manuscript, we assess the various drug delivery strategies in the context of being used research tools and eventual developability as therapeutic agents.

Diet phytochemicals and cutaneous carcinoma chemoprevention: A review

Cutaneous carcinoma, which has occupied a peculiar place among worldwide populations, is commonly responsible for the considerably increasing morbidity and mortality rates. Currently available medical procedures fail to completely avoid cutaneous carcinoma development or to prevent mortality. Cancer chemoprevention, as an alternative strategy, is being considered to reduce the incidence and burden of cancers through chemical agents. Derived from dietary foods, phytochemicals have become safe and reliable compounds for the chemoprevention of cutaneous carcinoma by relieving multiple pathological processes, including oxidative damage, epigenetic alteration, chronic inflammation, angiogenesis, etc. In this review, we presented comprehensive knowledges, main molecular mechanisms for the initiation and development of cutaneous carcinoma as well as effects of various diet phytochemicals on chemoprevention.

SIRT3 Mediates the Antioxidant Effect of Hydrogen Sulfide in Endothelial Cells

AIM

Oxidative stress is a key contributor to endothelial dysfunction and associated cardiovascular pathogenesis. Hydrogen sulfide (H2S) is an antioxidant gasotransmitter that protects endothelial cells against oxidative stress. Sirtuin3 (SIRT3), which belongs to the silent information regulator 2 (SIR2) family, is an important deacetylase under oxidative stress. H2S is able to regulate the activity of several sirtuins. The present study aims to investigate the role of SIRT3 in the antioxidant effect of H2S in endothelial cells.

RESULTS

Cultured EA.hy926 endothelial cells were exposed to hydrogen peroxide (H2O2) as a model of oxidative stress-induced cell injury. GYY4137, a slow-releasing H2S donor, improved cell viability, reduced oxidative stress and apoptosis, and improved mitochondrial function following H2O2 treatment. H2S reversed the stimulation of MAPK phosphorylation, downregulation of SIRT3 mRNA and reduction of the superoxide dismutase 2 and isocitrate dehydrogenase 2 expression which were induced by H2O2. H2S also increased activator protein 1 (AP-1) binding activity with SIRT3 promoter and this effect was absent in the presence of the specific AP-1 inhibitor, SR11302 or curcumin. Paraquat administration to mice induced a defected endothelium-dependent aortic vasodilatation and increased oxidative stress in both mouse aorta and small mesenteric artery, which were alleviated by GYY4137 treatment. This vasoprotective effect of H2S was absent in SIRT3 knockout mice.

INNOVATION

The present results highlight a novel role for SIRT3 in the protective effect of H2S against oxidant damage in the endothelium both in vitro and in vivo.

CONCLUSION

H2S enhances AP-1 binding activity with the SIRT3 promoter, thereby upregulating SIRT3 expression and ultimately reducing oxidant-provoked vascular endothelial dysfunction. Antioxid. Redox Signal. 24, 329-343.

Roles of phosphatidylinositol 3-kinase regulatory subunit alpha, activator protein-1, and programmed cell death 4 in diagnosis of papillary thyroid carcinoma

This study evaluated the diagnostic values of phosphatidylinositol 3-kinase regulatory subunit alpha (P85α), activator protein-1 (AP-1), and programmed cell death 4 (PDCD4) in papillary thyroid carcinoma (PTC). P85α, AP-1, and PDCD4 expressions were detected in PTC tissues (n = 116) and thyroid papillary hyperplasia (PTH) tissues (n = 90) by immunohistochemistry, western blot, and enzyme-linked immunosorbent assay (ELISA). Associations of P85α, AP-1, and PDCD4 expressions with clinicopathological features in PTC were analyzed. Diagnostic values of P85α, AP-1, and PDCD4 in PTC were evaluated by receiver operating characteristic (ROC) curve. P85α, AP-1, and PDCD4 expression levels in PTC tissues were statistically different from those in PTH tissues (all P < 0.05). In PTC tissues, AP-1 expression was positively associated with P85α expression (r = 0.841, P < 0.01), while negatively associated with PDCD4 expression (r = -0.755, P < 0.01). P85α expression was associated with lymph node metastasis (LNM) and the degree of differentiation (both P < 0.05); AP-1 and PDCD4 expressions were associated with the degree of differentiation (both P < 0.05). The diagnostic sensitivity and specificity of P85α were 92.2 and 91.1 %, respectively, with a cutoff value of 2.100 and an area under curve (AUC) of 0.966. The diagnostic sensitivity and specificity of AP-1 reached 94.4 and 93.3 % with a cutoff value of 1.655 and an AUC of 0.987. The diagnostic sensitivity and specificity of PDCD4 were 54.4 and 85.6 % with a cutoff value of 2.025 and an AUC of 0.754. P85α, AP-1, and PDCD4 proteins may be related to the tumorigenesis and progression of PTC. Moreover, P85α, AP-1, and PDCD4 proteins may serve as potential diagnostic markers to the biological behavior of PTC.

Hydrogen sulfide prodrugs-a review

Hydrogen sulfide (H₂S) is recognized as one of three gasotransmitters together with nitric oxide (NO) and carbon monoxide (CO). As a signaling molecule, H₂S plays an important role in physiology and shows great potential in pharmaceutical applications. Along this line, there is a need for the development of H₂S prodrugs for various reasons. In this review, we summarize different H₂S prodrugs, their chemical properties, and some of their potential therapeutic applications.

Garlic Oil Suppressed Nitrosodiethylamine-Induced Hepatocarcinoma in Rats by Inhibiting PI3K-AKT-NF-κB Pathway

To explore the underlying mechanisms for the protective effects of garlic oil (GO) against nitrosodiethylamine (NDEA)-induced hepatocarcinoma, 60 male Wistar rats were randomized into 4 groups (n=15): control group, NDEA group, and two GO plus NDEA groups. The rats in GO plus NDEA groups were pretreated with GO (20 or 40 mg/kg) for 7 days. Then, all rats except those in control group were gavaged with NDEA for 20 weeks, and the rats in GO plus NDEA groups were continuously administered with GO. The results showed that GO co-treatment significantly suppressed the NDEA-induced increases of alpha fetal protein (AFP) level in serum, nuclear atypia in H&E staining, sirius red-positive areas and proliferating cell nuclear antigen (PCNA) expression. The molecular mechanisms exploration revealed that the protein levels of phosphatidylinositol 3 kinase (PI3K)-p85, PI3K-p110, total AKT, p-AKT (Ser473) and p-AKT (Thr308) in the liver of NDEA group rats were higher than those in control group rats. In addition, NDEA treatment induced IκB degradation and NF-κB p65 phosphorylation, and up-regulated the protein levels of downstream pro-inflammatory mediators. GO co-treatment significantly reversed all the above adverse effects induced by NDEA. These results suggested that the protective effects of GO against NDEA-induced hepatocarcinoma might be associated with the suppression of PI3K- AKT-NF-κB pathway.

Viscum album-mediated COX-2 inhibition implicates destabilization of COX-2 mRNA

Extensive use of Viscum album (VA) preparations in the complementary therapy of cancer and in several other human pathologies has led to an increasing number of cellular and molecular approaches to explore the mechanisms of action of VA. We have recently demonstrated that, VA preparations exert a potent anti-inflammatory effect by selectively down-regulating the COX-2-mediated cytokine-induced secretion of prostaglandin E2 (PGE2), one of the important molecular signatures of inflammatory reactions. In this study, we observed a significant down-regulation of COX-2 protein expression in VA-treated A549 cells however COX-2 mRNA levels were unaltered. Therefore, we hypothesized that VA induces destabilisation of COX-2 mRNA, thereby depleting the available functional COX-2 mRNA for the protein synthesis and for the subsequent secretion of PGE2. To address this question, we analyzed the molecular degradation of COX-2 protein and its corresponding mRNA in A549 cell line. Using cyclohexamide pulse chase experiment, we demonstrate that, COX-2 protein degradation is not affected by the treatment with VA whereas experiments on transcriptional blockade with actinomycin D, revealed a marked reduction in the half life of COX-2 mRNA due to its rapid degradation in the cells treated with VA compared to that in IL-1β-stimulated cells. These results thus demonstrate that VA-mediated inhibition of PGE2 implicates destabilization of COX-2 mRNA.

PF2405, standardized fraction of Scutellaria baicalensis, ameliorates colitis in vitro and in vivo

Standardized extraction procedures for herb are as important as their authentication to maintain their quality and ensure their safe use. We had prepared a standardized and purified Scutellaria baicalensis Georgi extract, PF2405, which was enriched with three major components, baicalein, oroxylin A and wogonin. In the present study, we investigated the potential anti-inflammatory effects of PF2405 in vitro and in two different experimental animal models of inflammatory bowel disease. Effect of PF2405 studied in tumor necrosis factor (TNF)-α-induced HT-29 cells in vitro. In vivo experimental colitis models were induced by administration of trinitrobenzene sulfonic acid (TNBS) or dextran sulfate sodium (DSS). PF2405 (50 μg/ml) decreased TNF-α-induced cyclooxygenase (COX)-2 expressions through inhibition of phosphorylation of c-Jun N-terminal kinases and p38 mitogen-activated protein kinase in HT-29 cells. Combination of baicalein (20 μg/ml), oroxylin A (8 μg/ml), and wogonin (2 μg/ml) markedly inhibits TNF-α-induced COX-2 expression when compared with individual components. PF2405 (25 mg/kg b.w.) treatment significantly reduced histopathological severity; suppressed expression of COX-2, TNF-α, and interleukin-1β in TNBS-induced mice. Moreover, PF2405 (25 mg/kg b.w.) has both potent preventive and therapeutic activities in DSS-induced colitis. Collectively, PF2405 shows prominent anti-inflammatory effect that can be used as a new therapeutic approach for intestinal inflammatory disorders.

Ameliorative effect of diallyl trisulphide on arsenic-induced oxidative stress in rat erythrocytes and DNA damage in lymphocytes

BACKGROUND

Arsenic (As) is a naturally occurring semimetallic element that is classified as a toxicant and a human carcinogen. Diallyl trisulphide (DATS), an organosulphur compound, is an antioxidative substance that is extracted from garlic (Allium sativum). Erythrocytes are very expedient models to understand the susceptibility of membrane to oxidative damage induced by different xenobiotic compounds. Arsenic has been reported to induce oxidative stress to erythrocytes due to lipid peroxidation and alteration in defence mechanism as erythrocytes are the first target that arsenic compounds attack in the body after systemic absorption. In the light of this fact, the purpose of this study is to characterise the ameliorative effect of DATS on arsenic-induced oxidative stress in rat erythrocytes.

METHODS

Experimental rats were randomly divided into four groups and treated orally for 28 days: control, As [5 mg/kg body weight (BW)] treated, As+DATS (80 mg/kg BW) treated, DATS (80 mg/kg BW) treated and As+vitamin C (100 mg/kg BW) treated. Oxidative stress in erythrocytes was recorded by estimating plasma marker enzymes, plasma and erythrocyte membrane oxidative stress markers, erythrocyte membrane antioxidant enzymes and non-antioxidant enzymes, etc.

RESULTS

Oral administration of arsenic at 5 mg/kg BW per day elevated the levels of plasma marker enzymes, namely, aspartate transaminase (AST), alanine transaminase (ALT), acid phosphatase (ACP), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and γ-glutamyl transferase (γGT) (U/L) with significantly increased lipid peroxidation markers such as thiobarbituric acid reactive substances (TBARS), malondialdehyde (MDA), lipid hydroperoxides (LH), conjugated dienes (CD), and protein carbonyl (PC) contents were also elevated in As-treated rat plasma and erythrocytes. The levels of non-enzymatic antioxidants (reduced glutathione, vitamins C and E) and enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione reductase (GR), and glucose-6-phosphate dehydrogenase (G6PD) were also decreased in As-treated rats. The toxic effect of As significantly decreased the activities of membrane-bound ATPases (Na+/K+-ATPase, Mg2+-ATPase, and Ca2+-ATPase), with a significant increase in% tail DNA of rat lymphocytes measured by means of a single-cell gel electrophoresis assay. Administration of DATS for 28 days significantly reduced the levels of plasma markers. The levels of TBARS, MDA, LH, CD, and PC were significantly decreased and there was a significant increase in ATPase activities and non-enzymatic and enzymatic antioxidants on treatment with DATS in a dose-related manner.

CONCLUSIONS

All these changes were supported by reduction of DNA damage in lymphocytes with DATS treatment. DATS at a dose of 80 mg/kg BW was found to be most effective and the results revealed the same. The results of the study showed that DATS shows a protective effect against As-induced oxidative stress in rat erythrocytes and lymphocytes.

Piceatannol inhibits phorbol ester-induced expression of COX-2 and iNOS in HR-1 hairless mouse skin by blocking the activation of NF-κB and AP-1

OBJECTIVES

The present study was aimed at elucidating the molecular mechanisms of anti-inflammatory activity of piceatannol (trans-3,4,3',5'-tetrahydroxystilbene) in mouse skin in vivo.

METHODS

Female HR-1 hairless mice were topically treated with 12-O-tetradecanoylphorbol-13-acetate (TPA) with or without piceatannol pretreatment. Epidermal protein expression was assessed by Western blot analysis. The cyclooxygenase-2 (COX-2) expression was detected by immunohistochemistry. The DNA binding of nuclear factor-kappaB (NF-κB) and activator protein-1 (AP-1) was examined by the electrophoretic mobility gel shift assay. The catalytic activity of IκBα kinase-β (IKKβ) was measured by in vitro kinase assay.

RESULTS

Pretreatment with piceatannol attenuated TPA-induced expression of COX-2 and inducible nitric oxide synthase (iNOS) in mouse skin. Piceatannol diminished nuclear translocation and the DNA binding of NF-κB through the blockade of phosphorylation and subsequent degradation of IκBα. Piceatannol attenuated the catalytic activity of IKKβ and inhibited the phosphorylation of mitogen-activated protein (MAP) kinases in TPA-treated mouse skin. In addition, piceatannol decreased TPA-induced expression of c-Fos and the DNA binding of AP-1.

CONCLUSION

Piceatannol inhibits TPA-induced COX-2 and iNOS expression by blocking the activation of NF-κB and AP-1 via suppression of the IKKβ activity and phosphorylation of MAP kinases, which provides a mechanistic basis of its anti-inflammatory effects in mouse skin.

Epigallocatechin-3-gallate exerts protective effects against heat stress through modulating stress-responsive transcription factors in poultry

1. The aim of the study was to describe the effect of Epigallocatechin-3-gallate (EGCG), a polyphenol derived from green tea, on activator protein-1 (AP-1) components (phospho-c-Jun and c-Fos), cyclooxygenase-2 (COX-2) and heat shock proteins (HSPs) in the liver of heat-stressed quails. 2. A total of 180 5-week-old female Japanese quails were reared either at 22°C for 24 h/d (thermoneutral, TN) or 34°C for 8 h/d (heat stress, HS) for 12 weeks. Birds in both environments were randomly given 1 of 3 diets: basal diet and basal diet with 200 or 400 mg of EGCG added per kilogram of diet. 3. The hepatic c-Jun, c-Fos, COX-2 and HSPs gene expression for quails reared under the HS environment was greater than those reared under the TN environment. Supplemental EGCG decreased hepatic expression of these proteins at a greater extent under HS than TN. 4. In conclusion, suppression of AP-1 COX-2 and HSPs may partly account for the inhibitory effect of EGCG in heat-stressed quail.

Cigarette sidestream smoke induces histone H3 phosphorylation via JNK and PI3K/Akt pathways, leading to the expression of proto-oncogenes

Post-translational modifications in histones have been associated with cancer. Although cigarette sidestream smoke (CSS) as well as mainstream smoke are carcinogens, the relationship between carcinogenicity and histone modifications has not yet been clarified. Here, we demonstrated that CSS induced phosphorylation of histones, involving a carcinogenic process. Treatment with CSS markedly induced the phosphorylation of histone H3 at serine 10 and 28 residues (H3S10 and H3S28), which was independent from the cell cycle, in the human pulmonary epithelial cell model, A549 and normal human lung fibroblasts, MRC-5 and WI-38. Using specific inhibitors and small interfering RNA, the phosphorylation of H3S10 was found to be mediated by c-jun N-terminal kinase (JNK) and phosphoinositide 3-kinase (PI3K)/Akt pathways. These pathways were different from that of the CSS-induced phosphorylation of histone H2AX (γ-H2AX) mediated by Ataxia telangiectasia-mutated (ATM) and ATM-Rad3-related (ATR) protein kinases. A chromatin immunoprecipitation assay revealed that the phosphorylation of H3S10 was increased in the promoter sites of the proto-oncogenes, c-fos and c-jun, which indicated that CSS plays a role in tumor promotion. Because the phosphorylation of H3S10 was decreased in the aldehyde-removed CSS and was significantly induced by treatment with formaldehyde, aldehydes are suspected to partially contribute to this phosphorylation. These findings suggested that any chemicals in CSS, including aldehydes, phosphorylate H3S10 via JNK and PI3K/Akt pathways, which is different from the DNA damage response, resulting in tumor promotion.

Hydrogen sulfide donors in research and drug development

This review summarized most of the H₂S donors such as inorganic compounds, natural products, anethole trithione derivatives and synthetic compounds used in research and drug development. These special bioactivities provided us some effective strategies for antiphlogosis, cancer therapy, cardiovascular protection and so on.

Anti-inflammatory and anticancer drugs from nature

Over the centuries, plant extracts have been used to treat various diseases. Until now, natural products have played an important role in anticancer therapy as there are more than 500 compounds from terrestrial and marine plants or microorganisms, which have antioxidant, antiproliferative, or antiangiogenic properties and are therefore able to reduce tumor growth. The recent discovery of new natural products has been accelerated by novel technologies (high throughput screening of natural products in plants, animals, marine organisms, and microorganisms). Vincristine, irinotecan, etoposide, and paclitaxel are examples of compounds derived from plants that are used in cancer treatment. Similarly, actinomycin D, mitomycin C, bleomycin, doxorubicin, and L-asparaginase are drugs derived from microorganisms. In this review, we describe the molecular mechanisms of natural compounds with anti-inflammatory and anticancer activities.

Potential therapeutic effects of functionally active compounds isolated from garlic

The medicinal properties of functionally active organosulfur compounds such as allin, diallyl disulfide, S-allylmercaptocysteine, and S-trityl-L-cysteine isolated from garlic have received great attention from a large number of investigators who have studied their pharmacological effects for the treatment of various diseases. These organosulfur compounds are able to prevent for development of cancer, cardiovascular, neurological, and liver diseases as well as allergy and arthritis. There have been also many reports on toxicities and pharmacokinetics of these compounds. The aim of this study is to review a variety of experimental and clinical reports, and describe the effectiveness, toxicities and pharmacokinetics, and possible mechanisms of pharmaceutical actions of functionally active compounds isolated from garlic.

The preventive role of breadfruit against inflammation-associated epithelial carcinogenesis in mice

Artocarpus communis has been identified as a rich source of flavonoids and has been gaining attention for its potential chemopreventive abilities. In this study, methanol extracts from the fruit of A. communis (MEFA) and leaf of A. communis (MELA) were prepared, and their effects on inflammation-associated skin tumorigenesis were assessed using mouse models, including 12-O-tetradecanoylphorbol-13-acetate (TPA) induced cutaneous inflammation as well as 7,12-dimethylbenz[α]anthracene (DMBA) initiated and TPA-promoted skin tumorigenesis. According to the results, both MEFA and MELA decreased the intensity of leukocyte infiltration in mouse dorsal skin and cutaneous edema induced by TPA, which appeared to be mediated by inhibition of proinflammatory genes (inducible nitric oxide synthase, cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), IL-1β, and IL-6) and proinflammatory mediators (TNF-α, IL-1β, and Prostaglandin E2 ). In addition, topical application with MEFA or MELA effectively attenuated tumor incidence, multiplicity, volume, malignancy as well as angiogenesis of TPA-stimulated skin tumor promotion in DMBA-initiated mice. Notably, immunohistochemical stain showed that MEFA and MELA attenuated COX-2 expression of both skin and tumor tissues in different animal tests, which may be closely related to the suppression of nuclear factor kappa B/activator protein signaling networks. These findings first demonstrate that flavonoid-rich A. communis may exert potent anti-inflammatory activity through modulation of COX-2 in TPA-activated skin and tumor tissues.

Critical role for reactive oxygen species in apoptosis induction and cell migration inhibition by diallyl trisulfide, a cancer chemopreventive component of garlic

Diallyl trisulfide (DATS) is a structurally simple but biologically active constituent of processed garlic with in vivo activity against chemically induced as well as oncogene-driven cancer in experimental rodents. This study offers novel insights into the mechanisms underlying anticancer effects of DATS using human breast cancer cells as a model. Exposure of human breast cancer cells (MCF-7 and MDA-MB-231) and a cell line derived from spontaneously developing mammary tumor of a transgenic mouse (BRI-JM04) to DATS resulted in a dose-dependent inhibition of cell viability that was accompanied by apoptosis induction. A non-tumorigenic normal human mammary cell line (MCF-10A) was resistant to growth inhibition and apoptosis induction by DATS. The DATS-induced apoptosis in MDA-MB-231, MCF-7, and BRI-JM04 cells was associated with reactive oxygen species (ROS) production as evidenced by fluorescence microscopy and flow cytometry using a chemical probe (MitoSOX Red). Overexpression of Cu,Zn-superoxide dismutase (Cu,Zn-SOD) as well as Mn-SOD conferred significant protection against DATS-induced ROS production and apoptotic cell death in MDA-MB-231 and MCF-7 cells. Activation of Bak, but not Bax, resulting from DATS treatment was markedly suppressed by overexpression of Mn-SOD. The DATS treatment caused ROS generation, but not activation of Bax or Bak, in MCF-10A cells. Furthermore, the DATS-mediated inhibition of cell migration was partially but significantly attenuated by Cu,Zn-SOD and Mn-SOD overexpression in association with changes in levels of proteins involved in epithelial-mesenchymal transition. The DATS-mediated induction of heme oxygenase-1 was partially attenuated by overexpression of Mn-SOD. These results provide novel mechanistic insights indicating a critical role for ROS in anticancer effects of DATS.

Molecular mechanisms of garlic-derived allyl sulfides in the inhibition of skin cancer progression

Skin cancer is a serious concern whose incidence is increasing at an alarming rate. Allyl sulfides—i.e., sulfur metabolites in garlic oil—have been demonstrated to have anticancer activity against several cancer types, although the mechanisms underlying these effects remain enigmatic. Our previous study showed that diallyl trisulfide (DATS) is more potent than mono- and disulfides against skin cancer. DATS inhibits cell growth of human melanoma A375 cells and basal cell carcinoma (BCC) cells by increasing the levels of intracellular reactive oxygen species (ROS) and DNA damage and by inducing G2/M arrest, endoplasmic reticulum (ER) stress, and mitochondria-mediated apoptosis, including the caspase-dependent and -independent pathways. This short review focuses on the molecular mechanisms of garlic-derived allyl sulfides on skin cancer prevention.

Phorbol esters isolated from Jatropha meal induced apoptosis-mediated inhibition in proliferation of chang and Vero cell lines

The direct feeding of Jatropha meal containing phorbol esters (PEs) indicated mild to severe toxicity symptoms in various organs of different animals. However, limited information is available on cellular and molecular mechanism of toxicity caused by PEs present in Jatropha meal. Thus, the present study was conducted to determine the cytotoxic and mode of action of PEs isolated from Jatropha meal using human hepatocyte (Chang) and African green monkey kidney (Vero) cell lines. The results showed that isolated PEs inhibited cell proliferation in a dose-dependent manner in both cell lines with the CC₅₀ of 125.9 and 110.3 μg/mL, respectively. These values were compatible to that of phorbol 12-myristate 13-acetate (PMA) values as positive control i.e., 124.5 and 106.3 μg/mL respectively. Microscopic examination, flow cytometry and DNA fragmentation results confirmed cell death due to apoptosis upon treatment with PEs and PMA at CC₅₀ concentration for 24 h in both cell lines. The Western blot analysis revealed the overexpression of PKC-Δ and activation of caspase-3 proteins which could be involved in the mechanism of action of PEs and PMA. Consequently, the PEs isolated form Jatropha meal caused toxicity and induced apoptosis-mediated proliferation inhibition toward Chang and Vero cell lines involving over-expression of PKC-Δ and caspase-3 as their mode of actions.

Pkb/Akt1 mediates Wnt/GSK3β/β-catenin signaling-induced apoptosis in human cord blood stem cells exposed to organophosphate pesticide monocrotophos

Inhibition mechanisms of protein kinase B (Pkb)/Akt and its consequences on related cell signaling were investigated in human umbilical cord blood stem cells (hUCBSCs) exposed to monocrotophos (MCP, an organophosphate pesticide). In silico data reveal that MCP interacts with kinase and c-terminal regulatory domains of Akt1, resulting into a total docking score of 5.2748 and also forms H-bond between its N-H and Thr-291 residue of Akt1, in addition to possessing several hydrophobic interactions. The main cause of Akt inhibition is considered to be the strong hydrogen bond between N-H and Thr-291, and hydrophobic interactions at Glu-234, and Asp-292 in the vicinity, which is usually occupied by the ribose of ATP, and interaction with residue Phe-161, thus leading to a significant conformational change in that particular portion of the protein. In silico data on Akt inhibition were confirmed by examining the downregulation of phosphorylated (Thr308/Ser493) Akt1 in MCP-exposed hUCBSCs. MCP-mediated altered levels of pAkt downstream targets viz., downregulated pGSK3β (Ser9), unchanged GSK3αβ, and upregulated levels of Bad, P(53), and caspase-9 further confirm the inhibition of pAkt. The cellular fate of such pAkt inhibition was confirmed by increased terminal deoxynucleotide transferase dUTP nick-end labeling positive cells, reduced mitochondrial membrane potential, and the activation of various MAPKs, proapoptotic markers-Bax, and caspases-9/3. Our data demonstrate that Akt1 plays a key role in MCP-induced apoptosis in hUCBSCs. We also identified that such cellular responses of human cord blood stem cells against MCP were due to strong binding and inhibition of kinase and AGC-Kinase-C terminal regulatory domains of Akt1.

The Effect of Diallyl Polysulfanes on Cellular Signaling Cascades

Diallyl polysulfanes, such as diallyl trisulfide and diallyl tetrasulfide, are regarded as a group of potential chemopreventive compounds as they have been proven to be effective inhibitors of cancer cells. These agents have been implicated in signal transductions, including the generation of Reactive Oxygen Species (ROS), Endoplasmic Reticulum (ER) stress, mitogen-activated protein kinase (MAPK) signaling, regulation of cell cycle progression, and induction of apoptosis. Nonetheless, certain aspects of the diallyl polysulfane triggered inhibitory effects on cancer cells are still not clear. Understanding the targeted signaling pathways may help to develop new strategies to treat cancer and other diseases. This review is therefore aimed at addressing the targeting of specific intracellular signal transduction cascades by these diallyl polysulfanes in order to shed some light on possible mechanisms of action of these compounds.

Differential role of PKC-induced c-Jun in HTLV-1 LTR activation by 12-O-tetradecanoylphorbol-13-acetate in different human T-cell lines

We have previously shown that TPA activates HTLV-1 LTR in Jurkat T-cells by inducing the binding of Sp1-p53 complex to the Sp1 site residing within the Ets responsive region 1 (ERR-1) of the LTR and that this activation is inhibited by PKCalpha and PKCepsilon. However, in H9 T-cells TPA has been noted to activate the LTR in two consecutive stages. The first stage is activation is mediated by PKCetta and requires the three 21 bp TRE repeats. The second activation mode resembles that of Jurkat cells, except that it is inhibited by PKCdelta. The present study revealed that the first LTR activation in H9 cells resulted from PKCetta-induced elevation of non-phosphorylated c-Jun which bound to the AP-1 site residing within each TRE. In contrast, this TRE-dependent activation did not occur in Jurkat cells, since there was no elevation of non-phosphorylated c-Jun in these cells. However, we found that PKCalpha and PKCepsilon, in Jurkat cells, and PKCetta and PKCdelta, in H9 cells, increased the level of phosphorylated c-Jun that interacted with the Sp1-p53 complex. This interaction prevented the Sp1-p53 binding to ERR-1 and blocked, thereby, the ERR-1-mediated LTR activation. Therefore, this PKC-inhibited LTR activation started in both cell types after depletion of the relevant PKCs by their downregulation. In view of these variable activating mechanisms we assume that there might be additional undiscovered yet modes of HTLV-1 LTR activation which vary in different cell types. Moreover, in line with this presumption we speculate that in HTLV-1 carriers the LTR of the latent provirus may also be reactivated by different mechanisms that vary between its different host T-lymphocyte subclones. Since this reactivation may initiate the ATL process, understanding of these mechanisms is essential for establishing strategies to block the possibility of reactivating the latent virus as preventive means for ATL development in carriers.

Diallyl trisulfide suppresses the adipogenesis of 3T3-L1 preadipocytes through ERK activation

Garlic and its organosulfur compounds display hypolipidemic effects by inhibiting fatty acid and cholesterol synthesis. We investigated the anti-adipogenic effect of diallyl trisulfide (DATS), the second most abundant organosulfide in garlic oil. We studied the effects of DATS in 3T3-L1 preadipocytes and the mechanism involved in its action. DATS (0-75 μM) inhibited CCAAT/enhancer-binding protein (C/EBP) α and β and peroxisome proliferator-activated receptor (PPAR) γ mRNA and protein levels in a dose- and time-dependent manner, leading to a decrease of fatty acid synthase (FAS) expression and lipid accumulation in 3T3-L1 cells. Insulin treatment induced a transient increase in ERK phosphorylation in 3T3-L1 preadipocytes, and maximal induction was observed at 5 min and then declined. DATS, however, sustained ERK phosphorylation up to 120 min. In the presence of PD98059, the phosphorylation of ERK and suppression of PPARγ expression and DNA binding activity of PPARγ by DATS were reversed, and lipid accumulation was restored. In conclusion, these results indicate that DATS inhibits the differentiation of 3T3-L1 preadipocytes into adipocytes. DATS is likely to act by prolonging ERK activation, which leads to the down-regulation of adipogenic transcription factor expression during adipogenesis. Our results suggest that garlic may have potential as an anti-obesity agent.