Molecular targets of cancer chemoprevention by garlic-derived organosulfides

Finding the Ajoene Sweet-Spot: Structure-Activity Relations that Govern its Blood Stability and Cancer Cytotoxicity

Ajoene is an organosulfur compound found in crushed garlic that exerts its anti-cancer activity by S-thiolating cysteine residues on proteins. Its development is hampered due to limited bioavailability, so in this study, we synthesised analogues of ajoene to probe the significance of the ajoene vinyl disulfide/sulfoxide core with respect to cytotoxicity and blood stability. Polar side groups were also incorporated to improve aqueous solubility. It was found that derivatives containing a vinyl disulfide functional group (4-7, as in ajoene), were more cytotoxic compared to analogues in which the double bond was removed, although the latter showed superior blood stability. It was also found that the allyl-S sulfur of the disulfide was more electrophilic to S-thiolysis based on the global electrophilicity index (ω) and the condensed electrophilic Fukui functionf k + ${{ f}_{\rm{k}}^{\rm{ + }} }$ . S-Thiolysis was found to be exergonic for the vinyl disulfides based on entropy and enthalpy computations with a deprotonated thiolate. Derivatisation to the dihydro (10, 12) and deoxydihydroajoenes (9, 11) produced analogues that were slightly less potent but with greatly improved blood stability. Taken together, the deoxydihydroajoenes present themselves as good candidates for further therapeutic development.

Hydrogen sulfide and its donors: Novel antitumor and antimetastatic agents for liver cancer

Hepatocellular carcinoma (HCC) is the sixth most frequent human cancer and the world's third most significant cause of cancer mortality. HCC treatment has recently improved, but its mortality continues to increase worldwide due to its extremely complicated and heterogeneous genetic abnormalities. After nitric oxide (NO) and carbon monoxide (CO), the third gas signaling molecule discovered is hydrogen sulfide (H₂S), which has long been thought to be a toxic gas. However, numerous studies have proven that H₂S plays many pathophysiological roles in mammals. Endogenous or exogenous H₂S can decrease cell proliferation, promote apoptosis, block cell cycle, invasion and migration through various cellular signaling pathways. This review analyzes and discusses the recent literature on the function and molecular mechanism of H₂S and H₂S donors in HCC, so as to provide convenience for the scientific research and clinical application of H₂S in the treatment of liver cancer.

Activity-Based Proteomic Identification of the S-Thiolation Targets of Ajoene in MDA-MB-231 Breast Cancer Cells

Garlic is a medicinal plant and spice that has been used for millennia for its health-promoting effects. These medicinal properties are associated with low molecular weight organosulfur compounds, produced following the crushing of garlic cloves. One of these compounds, ajoene, is proposed to act by S-thioallylating cysteine residues on target proteins whose identification in cancer cells holds great promise for understanding mechanistic aspects of ajoene's cancer cell cytotoxicity. To this end, an ajoene analogue (called biotin-ajoene, BA), containing a biotin affinity tag, was designed as an activity-based probe specific for the protein targets of ajoene in MDA-MB-231 breast cancer cells. BA was synthesized via a convergent "click" strategy and found to retain its cytotoxicity against MDA-MB-231 cells compared to ajoene. Widespread biotinylation of proteins was found to occur via disulfide bond formation in a dose-dependent manner, and the biotin-ajoene probe was found to share the same protein targets as its parent compound, ajoene. The biotinylated proteins were affinity-purified from the treated MDA-MB-231 cell lysate using streptavidin-coated magnetic beads followed by an on-bead reduction, alkylation, and digestion to liberate the peptide fragments, which were analyzed by liquid chromatography tandem mass chromatography. A total of 600 protein targets were identified, among which 91% overlapped with proteins with known protein cysteine modification (PCM) sites. The specific sites were enriched for those susceptible to S-glutathionylation (-SSG) (16%), S-sulfhydration (-SSH) (20%), S-sulfenylation (-SOH) (22%), and S-nitrosylation (-SNO) (31%). As target validation, both ajoene and a dansylated ajoene (DP) were found to S-thiolate the pure recombinant forms of glutathione S-transferase pi 1 (GSTP1) and protein disulfide isomerase (PDI), and the ajoene analogue DP was found to be a more potent inhibitor than 5,5-dithio-bis-(2-nitrobenzoic acid) (DTNB). Pathway analysis elucidated that ajoene targets functional and signaling pathways that are implicated in cancer cell survival, specifically cellular processes, metabolism, and genetic information processing pathways. The results of this study provide mechanistic insights into the character of the anti-cancer activity of the natural dietary compound ajoene.

Research Trend and Detailed Insights into the Molecular Mechanisms of Food Bioactive Compounds against Cancer: A Comprehensive Review with Special Emphasis on Probiotics

In an attempt to find a potential cure for cancer, scientists have been probing the efficacy of the food we eat and its bioactive components. Over the decades, there has been an exponentially increasing trend of research correlating food and cancer. This review explains the molecular mechanisms by which bioactive food components exhibit anticancer effects in several cancer models. These bioactive compounds are mainly plant based or microbiome based. While plants remain the primary source of these phytochemicals, little is known about probiotics, i.e., microbiome sources, and their relationships with cancer. Thus, the molecular mechanisms underlying the anticancer effect of probiotics are discussed in this review. The principal mode of cell death for most food bioactives is found to be apoptosis. Principal oncogenic signaling axes such as Akt/PI3K, JAK/STAT, and NF-κB seem to be modulated due to these bioactives along with certain novel targets that provide a platform for further oncogenic research. It has been observed that probiotics have an immunomodulatory effect leading to their chemopreventive actions. Various foods exhibit better efficacy as complete extracts than their individual phytochemicals, indicating an orchestrated effect of the food components. Combining bioactive agents with available chemotherapies helps synergize the anticancer action of both to overcome drug resistance. Novel techniques to deliver bioactive agents enhance their therapeutic response. Such combinations and novel approaches are also discussed in this review. Notably, most of the food components that have been studied for cancer have shown their efficacy in vivo. This bolsters the claims of these studies and, thus, provides us with hope of discovering anticancer agents in the food that we eat.

Plant Natural Products: Promising Resources for Cancer Chemoprevention

Cancer is a major factor threatening human health and life safety, and there is a lack of safe and effective therapeutic drugs. Intervention and prevention in premalignant process are effective ways to reverse carcinogenesis and prevent cancer from occurring. Plant natural products are rich in sources and are a promising source for cancer chemoprevention. This article reviews the chemopreventive effects of natural products, especially focused on polyphenols, flavonoids, monoterpene and triterpenoids, sulfur compounds, and cellulose. Meanwhile, the main mechanisms include induction of apoptosis, antiproliferation and inhibition of metastasis are briefly summarized. In conclusion, this article provides evidence for natural products remaining a prominent source of cancer chemoprevention.

Metabolic profiling of different wild and cultivated Allium species based on high-resolution mass spectrometry, high-performance liquid chromatography-photodiode array detector, and color analysis

Many plants of the genus Allium are widely cultivated and consumed for their nutraceutical and health-enhancing bioactive components effective in many metabolic and infectious diseases. In particular, Allium sativum L. (garlic), the most economically important Allium species, is known to present volatile, comparatively polar sulfur-containing compounds responsible for both the typical garlic aroma and antimicrobial property. More recently, the (moderately) polar portion of garlic metabolome, rich of polyphenols and amino acids, is gaining increasing interest as a source of antioxidants and primary nutrients. In this study, we have explored the chemical diversity of eight different hydroalcoholic extracts obtained by microwave-assisted extraction of white and red crop A. sativum and wild Allium triquetrum, Allium roseum, and Allium ampeloprasum, all originating from the Mediterranean Basin. The aim is to appraise their potential dietetic and healing value through an in-depth chemical characterization and contribute to preserve and exploit natural resources. The multimethodological method applied here is based on an untargeted metabolic profiling by means of high-resolution electrospray ionization Fourier-transform ion cyclotron resonance (ESI FT-ICR) mass spectrometry. More than 850 by ESI(+) and 450 by ESI(-) putative metabolites have been annotated covering all main classes of primary and secondary metabolites, including amino acids, alkaloids, organic and fatty acids, nucleotides, vitamins, organosulfur compounds, and flavonoids. The pigment and polyphenol components have been separated and quantified by a targeted chromatographic high-performance liquid chromatography-photodiode array detector (HPLC-PDA) and CIEL*a*b* colorimetric assay, showing characteristic yellow and red components in each extract, related to a different milieu of anthocyanins and flavonoids as assigned by high-resolution mass spectrometry (MS).

Design and in silico screening of aryl allyl mercaptan analogs as potential histone deacetylases (HDAC) inhibitors

The Zn⁺² HDACIs show promising anticancer activity. Allyl mercaptan (AM), a metastabilzed monomeric form of diallyl disulphide (DADS) shows better HDACI activity. The present work screens a dataset of aryl AM derivatives 1(a-g) for potential HDACI action viain silico models. DFT calculations predicted the geometrical parameters and frontier orbital calculations suggested better chemical reactivity. Negative chemical potential and NBO hyper conjugative interactions predicted their chemical stability. ADME study confirmed favourable drug likeliness. Molecular docked models suggested the formation of coordinate bond between sulphur of allylmercaptan and Zn²⁺ cofactor of HDAC8. Besides, models also predicted the dominance of hydrophobic interactions. The aryl AM analogs docked perfectly with HDAC3 as well. The glide score and S-Zn distance of compounds 1a, 1f and 1g were found to be better than allylmercaptan. Therefore, the designed aryl AM analogs filtered as better HDACIs. These could be further used for design and synthesis of new improved HDACIs.

Anticancer activities of vitamin K3 analogues

In a previous study we reported on the synthesis of 1,4-naphthoquinone-sulfides by thiolation of 1,4-naphthohydroquinones with primary aryl and alkyl thiols using laccase as catalyst. These compounds were synthesized as Vitamin K3 analogues. Vitamin K3 (VK3; 2-methyl-1,4-naphthoquinone; menadione) is known to have potent anticancer activity. This investigation reports on the anticancer activity of these VK3 analogues against TK10 renal, UACC62 melanoma, MCF7 breast, HeLa cervical, PC3 prostate and HepG2 liver cancer cell lines to evaluate their cytostatic effects. A 1,4-naphthohydroquinone derivative exhibited potent cytostatic effects (GI₅₀ = 1.66-6.75 μM) which were better than that of etoposide and parthenolide against several of the cancer cell lines. This compound produces reactive oxygen species and disrupts the mitochondrial membrane potential in the MCF7 breast cancer cell line which is an indication that the cells undergo apoptosis. The 1,4-naphthoquinone sulfides also had potent cytostatic effects (GI₅₀ = 2.82-9.79 μM) which were also better than that of etoposide, parthenolide and VK3 against several of the cancer cell lines. These compounds are generally more selective for cancer cells than for normal human lung fetal fibroblasts (WI-38). They also have moderate to weak cytostatic effects compared to etoposide, parthenolide and VK3 which have potent cytostatic effects against WI-38. One analogue induces apoptosis by activating caspases without arresting the cell cycle in the MCF7 breast cancer cell line. These results inspire further research for possible application in cancer chemotherapy.

The Mediterranean Diet as source of bioactive compounds with multi-targeting anti-cancer profile

Many bioactive agents have been extracted from plants or belong to functional foods and have been considered in the treatment of serious and multifactorial diseases, such as cancer. In particular, this review is focused on the anti-cancer properties owned by several natural products typically from the Mediterranean area. In some regions of the South of Italy, a lower cancer incidence has been observed. There is increasing evidence that adherence to a Mediterranean dietary pattern correlates with reduced risk of several cancer types. This could be mainly attributed to the typical lifestyle aspects of the Mediterranean diet, such as high consumption of fruit and vegetables. In this review, the main natural products of the Mediterranean area are discussed, with particular attention on their anti-cancer properties endowed with multi-target profiles.

Ethanol extracts of Allium sp. regulate cyclooxygenase-2 and E-cadherin expression in gastric cancer MKN74 cell line and enhance doxorubicin toxicity

Background

Gastric cancer (GC) remains one of the leading causes of cancer-related death. Its aetiology is multifactorial, but the major risk factor is a high in salt diet. During gastric carcinogenesis, cadherin-1 (CDH1) down-expression and cyclooxygenase 2 (COX2) overexpression may be observed. The intensity of these alterations contributes to the GC invasion, its metastases and poor prognosis. As the diet plays a significant role in the aetiology of GC, it is reasonable to include the nutritional chemoprevention agents. One of the plant genus demonstrating chemoprotective properties is Allium genus, which includes garlic. The relationship between CDH1 and COX2 in GC cells treated with Allium species extract has never been evaluated.

Methods

In this study, the MKN28 and MKN74 GC cell lines were treated with ethanol extracts of Allium angulosum L., Allium lusitanicum Lam., Allium sativum L. (from Malaysia and Poland), Allium tibeticum Rendle and Allium ursinum L. The cytotoxicity of the extracts and their influence on COX2 and CDH1 mRNA and protein expression were evaluated as well as their influence on doxorubicin's (DOX) efficacy - a drug that has been used in GC treatment.

Results

Among the tested species, ethanol extracts of A. sativum L. (Poland and Malaysia), A. tibeticum Rendle and A. ursinum L. influenced the levels of CDH1 and COX2, but only in the MKN74 cell line. Thus, it is possible that tumours with increased COX2 expression will be more susceptible to garlic treatment. Observed phenomenon was independent of Allium extract's toxicity. In comparison to DOX, tested extracts were more toxic. Moreover, A. sativum revealed synergistic effect with the drug.

Conclusion

In conclusion, the results indicate the potential application of Allium genus to GC chemoprevention and treatment support through CDH restoration and COX2 downregulation. This issue needs further investigations as it might be used in clinics.

Anticancer activity, apoptosis and a structure-activity analysis of a series of 1,4-naphthoquinone-2,3-bis-sulfides

We have previously reported on the synthesis of 1,4-naphthoquinone-sulfides and in this investigation we report on their anticancer activity against 6 human cancer cell lines to evaluate their cytostatic effects. The 1,4-naphthoquinone-2,3-bis-sulfides were most effective against melanoma (UACC62) (GI₅₀ = 6.5-10 μM) and prostate (PC3) (GI₅₀ = 5.51-8.53 μM) cancer cell lines. They exhibited better cytostatic effects than etoposide (GI₅₀ = 0.56-36.62 μM), parthenolide (GI₅₀ = 3.58-25.97 μM) and VK3 (GI₅₀ = 3.41-22.59 μM) against several of the cancer cell lines. These compounds are generally more selective for cancer cells than for normal human lung fetal fibroblasts (WI-38). One compound produces ROS which results in breast (MCF7) cancer cell death caused by apoptosis as evidenced by caspase 3/7 activation. Apoptosis was found to occur by a mitochondrial pathway and not by cell cycle arrest. Gene expression studies showed that p53 (a tumour suppressor), Mdm-2 (a p53 regulator) and Bcl-2 (apoptosis inhibitor) were up-regulated during apoptosis induction. These results encourage further research for potential application in cancer chemotherapy.

Trisulfides over disulfides: highly selective synthetic strategies, anti-proliferative activities and sustained H2S release profiles

Highly selective synthesis of trisulfides over disulfides is demonstrated along with their potential as anti-proliferative agents and sustained donors of H₂S.

Effect of garlic powder on hippocampal long-term potentiation in rats fed high fat diet: an in vivo study

The objective of this study was to determine the relation between the chronic consumption of garlic powder in combination with high-fat diet (HFD) on long term potentiation (LTP) in the dentate gyrus (DG) of rat hippocampus. Male rats were divided to 4 groups, control with the standard diet, control with a standard diet plus garlic, high-fat diet (HFD) group and high-fat diet with garlic. Following 6 months of controlled dietary in each experimental group, the rats were anesthetized with i.p. injection of ketamine and xylazin (100 and 2.5 mg/kg, respectively), and placed into a stereotaxic apparatus for surgery, electrode implantation and field potential recording. The population spike (PS) amplitude and slope of excitatory post synaptic potentials (EPSP) were measured in the DG area of adult rats in response to stimulation applied to the perforant path (PP) (by 400 Hz tetanization). The results showed that garlic increased EPSP slope and PS amplitude respect to HFD group. It was suggested that the garlic powder administration could attenuate the deteriorating effect of HFD on in vivo hippocampal LTP in the granular cells of the DG.

Memory Improvement Effect of Ethanol Garlic (A. sativum) Extract in Streptozotocin-Nicotinamide Induced Diabetic Wistar Rats Is Mediated through Increasing of Hippocampal Sodium-Potassium ATPase, Glutamine Synthetase, and Calcium ATPase Activities

Studies suggest that garlic (A. sativum) improves memory dependent on the hippocampus. However, the effect of ethanol garlic extract on hippocampus Na⁺/K⁺ ATPase, Ca²⁺ ATPase, and glutamine synthetase (GS) activities as possible mechanisms in memory improvement in diabetic Wistar rats has not been reported. Twenty-four male Wistar rats weighing 200-250 g were divided into three groups with 8 rats each. Group (A), normal control rats, and Group (B), diabetic rats, received 1 ml of normal saline; diabetic rats in Group (C) received 1000 mg/kg of garlic extract orally for 21 days. Hyperglycemia was induced by a single intraperitoneal injection of streptozotocin 60 mg/kg followed by 120 mg/kg nicotinamide while extraction of garlic was done by cold maceration method. Memory was tested in all groups. After that, the rats were sacrificed, the brain was removed, and the hippocampi were carefully excised and then homogenized. Activities of Na⁺/K⁺ ATPase, calcium ATPase, and GS were analyzed from the homogenate. Results showed improvement in memory and a significant increase (P < 0.05) in hippocampus Na⁺/K⁺ ATPase, Ca²⁺ ATPase, and GS activities in diabetic rats treated with garlic extract. In conclusion, the increased activity of hippocampus Na⁺/K⁺ ATPase, calcium ATPase, and glutamine synthetase may account for the memory improvement.

International Union of Basic and Clinical Pharmacology. CII: Pharmacological Modulation of H2S Levels: H2S Donors and H2S Biosynthesis Inhibitors

Over the last decade, hydrogen sulfide (H2S) has emerged as an important endogenous gasotransmitter in mammalian cells and tissues. Similar to the previously characterized gasotransmitters nitric oxide and carbon monoxide, H2S is produced by various enzymatic reactions and regulates a host of physiologic and pathophysiological processes in various cells and tissues. H2S levels are decreased in a number of conditions (e.g., diabetes mellitus, ischemia, and aging) and are increased in other states (e.g., inflammation, critical illness, and cancer). Over the last decades, multiple approaches have been identified for the therapeutic exploitation of H2S, either based on H2S donation or inhibition of H2S biosynthesis. H2S donation can be achieved through the inhalation of H2S gas and/or the parenteral or enteral administration of so-called fast-releasing H2S donors (salts of H2S such as NaHS and Na2S) or slow-releasing H2S donors (GYY4137 being the prototypical compound used in hundreds of studies in vitro and in vivo). Recent work also identifies various donors with regulated H2S release profiles, including oxidant-triggered donors, pH-dependent donors, esterase-activated donors, and organelle-targeted (e.g., mitochondrial) compounds. There are also approaches where existing, clinically approved drugs of various classes (e.g., nonsteroidal anti-inflammatories) are coupled with H2S-donating groups (the most advanced compound in clinical trials is ATB-346, an H2S-donating derivative of the non-steroidal anti-inflammatory compound naproxen). For pharmacological inhibition of H2S synthesis, there are now several small molecule compounds targeting each of the three H2S-producing enzymes cystathionine-β-synthase (CBS), cystathionine-γ-lyase, and 3-mercaptopyruvate sulfurtransferase. Although many of these compounds have their limitations (potency, selectivity), these molecules, especially in combination with genetic approaches, can be instrumental for the delineation of the biologic processes involving endogenous H2S production. Moreover, some of these compounds (e.g., cell-permeable prodrugs of the CBS inhibitor aminooxyacetate, or benserazide, a potentially repurposable CBS inhibitor) may serve as starting points for future clinical translation. The present article overviews the currently known H2S donors and H2S biosynthesis inhibitors, delineates their mode of action, and offers examples for their biologic effects and potential therapeutic utility.

Lawsone suppresses azoxymethane mediated colon cancer in rats and reduces proliferation of DLD-1 cells via NF-κB pathway

Lawsone (LS) a colored napthoquinone compound obtained from the plant Lawsonia inermis L. (Lythraceae) is known for its usefulness of being a precursor for synthesis of some anticancer compounds. Literatures support potent anticancer activity of napthoquinone derivatives in human colon cancer, present study evaluates the effect and mechanism of LS on chemical induced colon cancerous rats and human colon cancer DLD-1 cells, the study was supported by endoscopy, histological and immunohistochemistry analysis. KAD rats were subjected to colon cancer mediated by Azoxymethane (AOM) injections followed Dextran sodium sulfate (DSS) orally in drinking water. After endoscopic confirmation the rats were given LS (200mg/ml) orally for 8 weeks. Presence of aberrant foci, types of tumors and the proliferative effect on tumor lesions was studied by macroscopic, histological and immunohistochemical analysis. To establish the mechanism, human colon DLD-1 cancer cells were exposed to LS and its effect on proliferation were studied. LS reduced aberrant crypt without affecting tumor pathology. Histological study of colon suggested decrease in numbers of adenomas and lesions. Immunohistochemistry confirmed the antiproliferative activity in adenocarcinomas without affecting the cells of normal colon mucosa. Results on human DLD-1 cells showed LS delayed progression of cell cycle by decreasing expression of cyclin B1 as well as cdk1 by inactivating NF-κB without inducing apoptosis. The study concluded role of LS in suppressing cell proliferation of colon tumors. The suppressive activity on DLD-1 cells was not by apoptosis but by decreased NF-κB activity resulting in suppression of expression levels of cyclin B1 and cdk1.

Forkhead Box Q1 Is a Novel Target of Breast Cancer Stem Cell Inhibition by Diallyl Trisulfide

Diallyl trisulfide (DATS), a metabolic byproduct of garlic, is known to inhibit the growth of breast cancer cells in vitro and in vivo This study demonstrates that DATS targets breast cancer stem cells (bCSC). Exposure of MCF-7 and SUM159 human breast cancer cells to pharmacological concentrations of DATS (2.5 and 5 μm) resulted in dose-dependent inhibition of bCSC, as evidenced by a mammosphere assay and flow cytometric analysis of aldehyde dehydrogenase 1 (ALDH1) activity and the CD44(high)/CD24(low)/epithelial specific antigen-positive fraction. DATS-mediated inhibition of bCSC was associated with a decrease in the protein level of FoxQ1. Overexpression of FoxQ1 in MCF-7 and SUM159 cells increased ALDH1 activity and the CD49f(+)/CD24(-) fraction. Inhibition of ALDH1 activity and/or mammosphere formation upon DATS treatment was significantly attenuated by overexpression of FoxQ1. In agreement with these results, stable knockdown of FoxQ1 using small hairpin RNA augmented bCSC inhibition by DATS. Expression profiling for cancer stem cell-related genes suggested that FoxQ1 may negatively regulate the expression of Dachshund homolog 1 (DACH1), whose expression is lost in invasive breast cancer. Chromatin immunoprecipitation confirmed recruitment of FoxQ1 at the DACH1 promoter. Moreover, inducible expression of DACH1 augmented DATS-mediated inhibition of bCSC. Expression of FoxQ1 protein was significantly higher in triple-negative breast cancer cases compared with normal mammary tissues. Moreover, an inverse association was observed between FoxQ1 and DACH1 gene expression in breast cancer cell lines and tumors. DATS administration inhibited ALDH1 activity in vivo in SUM159 xenografts. These results indicate that FoxQ1 is a novel target of bCSC inhibition by DATS.

Downregulation of PI3-K/Akt/PTEN pathway and activation of mitochondrial intrinsic apoptosis by Diclofenac and Curcumin in colon cancer

Phosphatidylinositol 3-kinase (PI3-K)/PTEN/Akt signaling is over activated in various tumors including colon cancer. Activation of this pathway regulates multiple biological processes such as apoptosis, metabolism, cell proliferation, and cell growth that underlie the biology of a cancer cell. In the present study, the chemopreventive effects have been observed of Diclofenac, a preferential COX-2 inhibitory non-steroidal anti-inflammatory drugs, and Curcumin, a natural anti-inflammatory agent, in the early stage of colorectal carcinogenesis induced by 1,2-dimethylhydrazine dihydrochloride in rats. The tumor-promoting role of PI3-K/Akt/PTEN signal transduction pathway and its association with anti-apoptotic family of proteins are also observed. Both Diclofenac and Curcumin downregulated the PI3-K and Akt expression while promoting the apoptotic mechanism. Diclofenac and Curcumin administration significantly increased the expression of pro-apoptotic Bcl-2 family members (Bad and Bax) while decreasing the anti-apoptotic Bcl-2 protein. An up-regulation of cysteine protease family apoptosis executioner, such as caspase-3 and -9, is seen. Diclofenac and Curcumin inhibited the Bcl-2 protein by directly interacting at the active site by multiple hydrogen bonding, as also evident by negative glide score of Bcl-2. These drugs stimulated apoptosis by increasing reactive oxygen species (ROS) generation and simultaneously decreasing the mitochondrial membrane potential (ΔΨ M). Diclofenac and Curcumin showed anti-neoplastic effects by downregulating PI3-K/Akt/PTEN pathway, inducing apoptosis, increasing ROS generation, and decreasing ΔΨ M. The anti-neoplastic and apoptotic effects were found enhanced when both Diclofenac and Curcumin were administered together, rather than individually.

Aged garlic extract inhibits 1,2-dimethylhydrazine-induced colon tumor development by suppressing cell proliferation

Garlic and its constituents are reported to have a preventive effect against colorectal cancer in animal models. Aged garlic extract (AGE), which is produced by natural extraction from fresh garlic for more than 10 months in aqueous ethanol, also has reputed chemopreventive effects on colon carcinogenesis, but has never been studied for its effects on colon cancer development. We investigated the antitumor effects of AGE in rats with 1,2-dimethylhydrazine (DMH)-induced carcinogenesis, and the mechanism of AGE in human colon cancer cell proliferation. F344 rats randomly divided into three groups were administered DMH (20 mg/kg weight) subcutaneously once a week for 8 weeks in a basal diet. After the last injection, one group of rats was then moved onto a basal diet containing 3% wt/wt AGE, and rats were sacrificed at 8 or 31 weeks. The number of aberrant crypt foci (ACF), histological type of tumor and proliferative activity of the tumor lesions were analyzed by macroscopic, pathological and immunohistochemical methods. DLD-1 human colon cancer cells were utilized to investigate the effect of AGE on anti-cell proliferation. AGE decreased the number of ACF but had no effect on gross tumor pathology. AGE showed a lower number of adenoma and adenocarcinoma lesions by histological analysis. Immunohistochemical staining indicated that AGE suppressed the proliferative activity in adenoma and adenocarcinoma lesions, but showed no effect on normal colon mucosa. Moreover, we demonstrated that AGE delayed cell cycle progression by downregulating cyclin B1 and cdk1 expression via inactivation of NF-κB in the human colorectal cancer cells but did not induce apoptosis. These findings suggest that AGE has an antitumor effect through suppression of cell proliferation.

Estonian folk traditional experiences on natural anticancer remedies: from past to the future

CONTEXT

Despite diagnostic and therapeutic advancements, the burden of cancer is still increasing worldwide. Toxicity of current chemotherapeutics to normal cells and their resistance to tumor cells highlights the urgent need for new drugs with minimal adverse side effects. The use of natural anticancer agents has entered into the area of cancer research and increased efforts are being made to isolate bioactive products from medicinal plants.

OBJECTIVE

To lead the search for plants with potential cytotoxic activity, ethnopharmacological knowledge can give a great contribution. Therefore, the attention of this review is devoted to the natural remedies traditionally used for the cancer treatment by Estonian people over a period of almost 150 years.

METHODS

Two massive databases, the first one stored in the Estonian Folklore Archives and the second one in the electronic database HERBA ( http://herba.folklore.ee/ ), containing altogether more than 30 000 ethnomedicinal texts were systematically reviewed to compile data about the Estonian folk traditional experiences on natural anticancer remedies.

RESULTS AND CONCLUSION

As a result, 44 different plants with potential anticancer properties were elicited, 5 of which [Angelica sylvestris L. (Apiaceae), Anthemis tinctoria L. (Asteraceae), Pinus sylvestris L. (Pinaceae), Sorbus aucuparia L. (Rosaceae), and Prunus padus L. (Rosaceae)] have not been previously described with respect to their tumoricidal activities in the scientific literature, suggesting thus the potential herbal materials for further investigations of natural anticancer compounds.

Diallyl trisulfide inhibits estrogen receptor-α activity in human breast cancer cells

Organosulfur compounds from garlic effectively inhibit growth of transplanted as well as spontaneous cancers in preclinical animal models without any adverse side effects. However, the mechanisms underlying anticancer effect of this class of compounds are not fully understood. This study reports, for the first time, that garlic organosulfide diallyl trisulfide (DATS) inhibits estrogen receptor-α (ER-α) activity in human breast cancer cells. Exposure of MCF-7 and T47D cells to DATS resulted in downregulation of ER-α protein, which peaked between 12- and 24-h post-treatment. DATS was relatively more effective in suppressing ER-α protein expression compared with its mono and disulfide analogs. The 17β-estradiol (E2)-induced expression of pS2 and cyclin D1, ER-α target gene products, was also decreased in the presence of DATS. Downregulation of ER-α protein expression resulting from DATS treatment was accompanied by a decrease in nuclear levels of ER-α protein, ER-α mRNA suppression, and inhibition of ERE2e1b-luciferase reporter activity. DATS-mediated inhibition of cell viability and apoptosis induction were not affected in the presence of E2. In agreement with these results, ectopic expression of ER-α in MDA-MB-231 cell line failed to confer any protection against cell proliferation inhibition or apoptosis induction resulting from DATS exposure. DATS treatment caused a decrease in protein levels of peptidyl-prolyl cis-trans isomerase (Pin1), and overexpression of Pin1 partially attenuated ER-α downregulation by DATS. DATS-induced apoptosis was modestly but significantly augmented by overexpression of Pin1. In conclusion, this study identifies ER-α as a novel target of DATS in mammary cancer cells.

Multi-targeted DATS prevents tumor progression and promotes apoptosis in ectopic glioblastoma xenografts in SCID mice via HDAC inhibition

Glioblastoma, the most lethal brain tumor, remains incurable despite aggressive chemotherapy and surgical interventions. New chemotherapeutics for glioblastoma have been explored in preclinical models and some agents have reached the clinical setting. However, success rates are not significant. Previous investigations involving diallyl trisulfide (DATS), a garlic compound, indicated significant anti-cancer effects in glioblastoma in vitro. DATS has also been shown to inhibit histone deacetylase activity and impede glioblastoma tumor progression. We hypothesized that DATS would block ectopic U87MG tumor by multiple pro-apoptotic pathways via inhibiting histone deacetylase (HDAC). To prove this, we developed ectopic U87MG tumors in SCID mice and treated them daily with intraperitoneal injections of DATS for 7 days. Results indicated that DATS (10 μg/kg-10 mg/kg) dose-dependently reduced tumor mass and number of mitotic cells within tumors. Histological and biochemical assays demonstrated that DATS reduced mitosis in tumors, decreased HDAC activity, increased acetylation of H3 and H4, inhibited cell cycle progression, decreased pro-tumor markers (e.g., survivin, Bcl-2, c-Myc, mTOR, EGFR, VEGF), promoted apoptotic factors (e.g., bax, mcalpian, active caspase-3), and induced DNA fragmentation. Our data also demonstrated an increase in p21Waf1 expression, which correlated with increased p53 expression and MDM2 degradation following DATS treatment. Finally, histological assessment and enzyme assays showed that even the highest dose of DATS did not negatively impact hepatic function. Collectively, our results clearly demonstrated that DATS could be an effective therapeutic agent in preventing tumor progression and inducing apoptosis in human glioblastoma in vivo, without impairing hepatic function.

HPLC-MTT assay: anticancer activity of aqueous garlic extract is from allicin

A strategy using reversed-phase high-performance liquid chromatography (HPLC), thin layer chromatography (TLC), mass spectrometry (MS), nuclear magnetic resonance (NMR), chemical synthesis, and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cell viability assay to identify allicin as the active anticancer compound in aqueous garlic extract (AGE) is described. Changing the pH of AGE from 7.0 to 5.0 eliminated interfering molecules and enabled a clean HPLC separation of the constituents in AGE. MTT assay of the HPLC fractions identified an active fraction. Further analysis by TLC, MS, and NMR verified the active HPLC fraction as allicin. Chemically synthesized allicin was used to provide further confirmation. The results clearly identify the active compound in AGE as allicin.

Hydrogen sulfide in biochemistry and medicine

SIGNIFICANCE

An abundance of experimental evidence suggests that hydrogen sulfide (H(2)S) plays a prominent role in physiology and pathophysiology. Many targets exist for H(2)S therapy. The molecular targets of H(2)S include proteins, enzymes, transcription factors, and membrane ion channels.

RECENT ADVANCES

Novel H(2)S precursors are being synthesized and discovered that are capable of releasing H(2)S in a slow and sustained manner. This presents a novel and advantageous approach to H(2)S therapy for treatment of chronic conditions associated with a decline in endogenous H(2)S, such as diabetes and cardiovascular disease.

CRITICAL ISSUES

While H(2)S is cytoprotective at physiological concentrations, it is not universally cytoprotective, as it appears to have pro-apoptotic actions in cancer cells and is well known to be toxic at supraphysiological concentrations. Many of the pleiotropic effects of H(2)S on health are associated with the inhibition of inflammation and upregulation of prosurvival pathways. The powerful anti-inflammatory, cytoprotective, immunomodulating, and trophic effects of H(2)S on the vast majority of normal cells seem to be mediated mainly by its actions as an extremely versatile direct and indirect antioxidant and free radical scavenger. While the overall effects of H(2)S on transformed (i.e., malignant) cells can be characterized as pro-oxidant and pro-apoptotic, they contrast sharply with the cytoprotective effects on most normal cells.

FUTURE DIRECTIONS

H(2)S has become a molecule of great interest, and several slow-releasing H(2)S prodrugs are currently under development. We believe that additional agents regulating H(2)S bioavailability will be developed during the next 10 years.

Apoptosis induction of U937 human leukemia cells by diallyl trisulfide induces through generation of reactive oxygen species

BACKGROUND

Diallyl trisulfide (DATS) is one of the major constituents in garlic oil and has demonstrated various pharmacological activities, including antimicrobial, antihyperlipidemic, antithrombotic, and anticancer effects. However, the mechanisms of antiproliferative activity in leukemia cells are not fully understood. In this study, the apoptotic effects of DATS were investigated in human leukemia cells.

RESULTS

Results of this study indicated that treatment with DATS resulted in significantly inhibited leukemia cell growth in a concentration- and time-dependent manner by induction of apoptosis. In U937 cells, DATS-induced apoptosis was correlated with down-regulation of Bcl-2, XIAP, and cIAP-1 protein levels, cleavage of Bid proteins, activation of caspases, and collapse of mitochondrial membrane potential. The data further demonstrated that DATS increased intracellular reactive oxygen species (ROS) generation, which was attenuated by pretreatment with antioxidant N-acetyl-l-cysteine (NAC), a scavenger of ROS. In addition, administration of NAC resulted in significant inhibition of DATS-induced apoptosis by inhibiting activation of caspases.

CONCLUSIONS

The present study reveals that the cytotoxicity caused by DATS is mediated by generation of ROS and subsequent activation of the ROS-dependent caspase pathway in U937 leukemia cells.

Vitamin, mineral, and specialty supplements and risk of hematologic malignancies in the prospective VITamins And Lifestyle (VITAL) study

BACKGROUND

Increasing evidence suggests that nutrients from fruits and vegetables have chemoprotective effects on various cancers including hematologic malignancies, but the effects of nutritional supplements are poorly examined.

METHODS

Herein, we prospectively evaluated the association of vitamin, mineral, and specialty supplements with incident hematologic malignancies in 66,227 men and women aged 50 to 76 years from Washington State recruited from year 2000 to 2002 to the VITamins And Lifestyle (VITAL) cohort study. Hematologic malignancies cases (n = 588) were identified through December 2008 by linkage to the Surveillance, Epidemiology, and End Results (SEER) cancer registry. HRs and 95% CIs associated with supplement use were estimated with Cox proportional hazards models.

RESULTS

After adjustment, high use of garlic supplements [≥4 days per week for ≥3 years; HR = 0.55 (95% CI = 0.34-0.87); P(trend) = 0.028] and ever use of grape seed supplements [HR = 0.57 (95% CI = 0.37-0.88)] were inversely associated with hematologic malignancies in our models. In addition, high use (8-10 pill-years) of multivitamins was suggestive of an inverse association [HR = 0.80 (95% CI = 0.64-1.01)]. In contrast, no associations were observed for the remaining supplements.

CONCLUSIONS

These data indicate that the use of garlic and grape seed may be associated with reduced risk of hematologic malignancies.

IMPACT

This is the first cohort study to suggest a possible role of these supplements in the chemoprevention of hematologic malignancies.

Impact of JNK1, JNK2, and ligase Itch on reactive oxygen species formation and survival of prostate cancer cells treated with diallyl trisulfide

PURPOSE

In our previous study, we demonstrated that diallyl trisulfide (DATS) induced iron-dependent G2-M arrest of prostate cancer cell cycle. Moreover, ferritin degradation and an increase of labile iron pool has been linked to the activation of the JNK signaling axis. In the present work, we extended this study to determine which of the c-jun kinases is responsible for ferritin degradation and the role of iron in DATS-induced cell death. We hypothesized that JNK1 activates Itch ligase which will lead to ferritin ubiquitination, an increase in iron-dependent ROS formation and cell death.

METHODS

PC-3 prostate cancer cells were used in this study. Cell viability, concentration of ROS, labile iron pool, and changes in ferritin and P-Itch and DNA damage were determined.

RESULTS

We observed that DATS induced ferritin degradation through JNK, Itch signaling axis. DATS did not induce neither ROS formation nor increase the LIP in JNK1-DN transfected cells. We also observed that DATS increased JNK-dependent activating phosphorylation of E3ligase Itch. The cells transfected with inactive form of Itch were more resistant against cytotoxicity of DATS and showed lower DATS-induced ferritin degradation. Desferrioxamine a specific iron chelator had no effect neither on cell viability nor DNA damage evaluated by comet assay.

CONCLUSIONS

These results suggest that JNK1-dependent increase in LIP is mediated by Itch ubiquitin ligase.

Induction of apoptosis with diallyl disulfide in AGS gastric cancer cell line

Purpose

Diallyl disulfide (DADS) is a major organosulfur compound derived from garlic. It has been reported that DADS is able to inhibit the proliferation of several tumor cells. In this study, the effect of DADS was investigated in terms of the proliferation of AGS, gastric adenocarcinoma cell line at various concentrations.

Methods

The viability of cultured cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. To detect the induction of apoptosis, Annexin V-FITC/propodium iodide (PI) staining assay was performed. Analysis of reactive oxygen species (ROS) and the distribution of cells in the cell cycle were measured by a flow cytometer. And using the Western blot analysis, the change of Fas, caspase-3, Bax, Bcl-2 activity was measured.

Results

The percentage of live AGS cells was decreased to 23% of that in the control group after 400 µM DADS treatment for 48 hours. The Annexin V positive/PI negative (apoptosis portion) area increased from low concentration of DADS to high concentration. When comparing among the DADS treatment groups, the amount of ROS production increased in a dose dependent manner. The percentage of sub-diploid DNA content increased from 8.71% at 50 µM to 25.74% at 400 µM DADS treatment group. The expressions of Fas, caspase-3, Bax were increased and that of Bcl-2 was decreased in a dose dependent manner.

Conclusion

DADS decreases the viability of AGS cell lines and induces apoptosis in a dose-dependent manner. But the relationship of the anti-proliferative effect of DADS and related molecular changes were not clearly proportional to the concentration of DADS.

Diallyl trisulfide (DATS) inhibits mouse colon tumor in mouse CT-26 cells allograft model in vivo

Our earlier studies showed that DATS induced apoptosis in human colon cancer HT29 and colo 205 cell lines in vitro. However, there is no report to show that DATS induced apoptosis in vitro and inhibited CT26 cancer cells in vivo on a murine allograft animal model. In vitro studies, the results indicated that DATS induced morphological changes and induction of apoptosis in CT26 cells. In vivo studies, CT26 cancer cells were implanted into BALB/c mice and groups of mice were treated with vehicle, DATS (10 and 50 mg/kg of body weight). DATS were injected once per four days intraperitoneally (i.p.), with treatment starting 4 weeks prior to cells inoculation. Treatment with vehicle or with 10 and 50 mg/kg of DATS resulted in a reduction in tumor volume and weight. Tumor volume and total hemoglobin in allograft mice treated with 50 mg/kg DATS were significantly smaller than that in the control group. These findings indicated that DATS inhibits tumor growth in an allograft animal model. Thus, DATS may represent a colon cancer preventive agent and can be used in the future.

Garlic constituent diallyl trisulfide suppresses x-linked inhibitor of apoptosis protein in prostate cancer cells in culture and in vivo

We have shown previously that garlic constituent diallyl trisulfide (DATS) inhibits growth of cultured and xenografted human prostate cancer cells in association with apoptosis induction, but the mechanism of cell death is not fully understood. The present study systematically investigates the role of inhibitor of apoptosis (IAP) family proteins in the regulation of DATS-induced apoptosis using cultured PC-3 and LNCaP human prostate cancer cells and dorsolateral prostate from control and DATS-treated transgenic adenocarcinoma of mouse prostate (TRAMP) mice. Level of X-linked inhibitor of apoptosis (XIAP) protein was decreased on 8-hour treatment with 20 and 40 μmol/L DATS, but this effect was partially attenuated at the 16-hour time point. DATS-mediated decline in XIAP protein level was partially reversible in the presence of proteasomal inhibitor MG132. In contrast, DATS-treated PC-3 and LNCaP cells exhibited marked induction of survivin and cellular inhibitor of apoptosis protein 1 (cIAP1) proteins. Induction of survivin protein expression resulting from DATS exposure was associated with an increase in its mRNA level. Dorsolateral prostates from DATS-treated TRAMP mice exhibited statistically significant downregulation of XIAP and induction of survivin protein compared with those of control mice. Ectopic expression of XIAP conferred partial but significant protection against DATS-induced apoptosis. On the other hand, DATS-induced apoptosis was only marginally affected by RNA interference of survivin or cIAP1. In conclusion, the present study indicates that the DATS-induced apoptosis in prostate cancer cells is mediated in part by suppression of XIAP protein expression, and that XIAP represents a viable biomarker of DATS response for future clinical investigations.

Chemopreventative potential of the cruciferous vegetable constituent phenethyl isothiocyanate in a mouse model of prostate cancer

BACKGROUND

This study was undertaken to determine the chemopreventative efficacy of phenethyl isothiocyanate (PEITC), a bioactive constituent of many edible cruciferous vegetables, in a mouse model of prostate cancer, and to identify potential biomarker(s) associated with PEITC response.

METHODS

The chemopreventative activity of dietary PEITC was investigated in Transgenic Adenocarcinoma of Mouse Prostate mice that were fed a control diet or one containing 3 μmol PEITC/g (n = 21 mice per group) for 19 weeks. Dorsolateral prostate tissue sections were stained with hematoxylin and eosin for histopathologic evaluations and subjected to immunohistochemistry for analysis of cell proliferation (Ki-67 expression), autophagy (p62 and LC3 protein expression), and E-cadherin expression. Autophagosomes were visualized by transmission electron microscopy. Apoptotic bodies were detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling. Plasma proteomics was performed by two-dimensional gel electrophoresis followed by mass spectrometry to identify potential biomarkers of PEITC activity. All statistical tests were two-sided.

RESULTS

Administration of PEITC (3 μmol/g diet) decreased incidence (PEITC diet vs control diet, mean = 21.65 vs 57.58%, difference = -35.93%, 95% confidence interval = -45.48% to -13.10%, P = .04) as well as burden (affected area) (PEITC diet vs control diet, mean = 18.53% vs 45.01%, difference = -26.48%, 95% confidence interval = -49.78% to -3.19%, P = .02) of poorly differentiated tumors in the dorsolateral prostate of transgenic mice compared with control mice, with no toxic effects. PEITC-mediated inhibition of prostate carcinogenesis was associated with induction of autophagy and overexpression of E-cadherin in the dorsolateral prostate. However, PEITC treatment was not associated with a decrease in cellular proliferation, apoptosis induction, or inhibition of neoangiogenesis. Plasma proteomics revealed distinct changes in the expression of several proteins (eg, suppression of clusterin protein) in the PEITC-treated mice compared with control mice.

CONCLUSIONS

In this transgenic model, dietary PEITC suppressed prostate cancer progression by induction of autophagic cell death. Potential biomarkers to assess the response to PEITC treatment in plasma were identified.

Histological and ultrastructural changes in the adult male albino rat testes following chronic crude garlic consumption

Several studies have presented Garlic (Allium sativum) as a restoring agent for testicular cells after exposure to different types of toxins, however, others have shown that it modified spermatogenesis and might have spermicidal effects. This work has been to assess the positive or negative effect of chronic crude garlic consumption on rat testes using light and transmission electron microscopy with reference to plasma testosterone and LH levels. Forty albino male rats were divided into group A (control) and group B (treated rats). Group B was further subdivided into B1, B2, and B3 subgroups which were administer crude garlic as 20% of their daily food for two, three and four months, respectively. The current study has been the first, to the best of our knowledge, to describe the apoptotic effect of chronic crude garlic consumption targeting Sertoli cells, germ cells and peritubular tissue including interstitial Leydig cells and myoid cells. This might be better explained by inflammatory than degenerative changes in the peritubular tissue and Leydig cells leading to a decrease in testosterone level. Consequently, Sertoli cells degenerate due to a decrease in testosterone and detachment from the basal lamina. Germ cells, which are completely dependent upon Sertoli cells and testosterone to complete there spermatogenesis will be affected. Testicular apoptosis with disruption in spermatogenesis following chronic crude garlic consumption could be correlated with two possible theories; being an anti-hypercholesterolemic agent, it might inhibit steroidogenesis resulting in a decrease in testosterone level and being one of the famous phytoestrogens it possibly has direct estrogen-like actions on adult male rat testes.

Diallyl trisulfide inhibits activation of signal transducer and activator of transcription 3 in prostate cancer cells in culture and in vivo

Signal transducer and activator of transcription 3 (STAT3) is an oncogenic transcription factor implicated in prostate carcinogenesis. The present study shows that diallyl trisulfide (DATS), a promising cancer-chemopreventive constituent of processed garlic, inhibits phosphorylation of STAT3 in prostate cancer cells in culture and in vivo. Exposure of DU145 and LNCaP human prostate cancer cells to growth-suppressive and pharmacologically relevant concentrations of DATS (20 and 40 μmol/L) resulted in suppression of constitutive (DU145) as well as interleukin-6 (IL-6)-induced (LNCaP) phosphorylation of STAT3 (Tyr(705)), which correlated with inhibition of Janus-activated kinase 2 phosphorylation. Constitutive and/or IL-6-induced nuclear translocation of pSTAT3 and STAT3 dimerization was also markedly inhibited on treatment with DATS in both cell lines. Inhibition of prostate cancer development in transgenic adenocarcinoma of mouse prostate mice by gavage of DATS correlated with a visible decrease in the levels of pSTAT3. Interestingly, the IL-6-mediated activation of STAT3 largely failed to confer protection against proapoptotic response to DATS in both cells. Likewise, DATS-mediated inhibition of cell migration was either not affected or minimally reversed by IL-6 treatment or ectopic expression of constitutively active STAT3. In conclusion, the present study indicates that DATS treatment suppresses STAT3 phosphorylation in prostate cancer cells in culture and in vivo, but activation of this oncogenic transcription factor is largely dispensable for cellular responses to DATS. Ability of DATS to overcome STAT3 activation is a therapeutic advantage for this chemopreventive agent.

Saffron suppresses oxidative stress in DMBA-induced skin carcinoma: A histopathological study

Cancer chemoprevention is the use of natural, synthetic or biological substances to reverse or prevent the development of cancer. Saffron is a naturally derived plant product that acts as an antispasmodic, diaphoretic, carminative, emmenagogic and sedative. Our aim in this study was to investigate the chemopreventive effect of aqueous saffron on chemically induced skin carcinogenesis using a histopathological approach. Mice were divided into five groups: carcinogen control (CC), normal control (NC) and saffron-treated Groups A, B and C. Groups A, B, C and CC mice received three topical applications of 7,12 dimethylbenz[a]anthracene (DMBA) followed by croton oil on shaven dorsal skin for 8 weeks. NC mice received topical skin applications of the vehicle, acetone, only. Saffron infusion was fed orally to three groups of mice either before (Group A) or after (Group C) or both before and after (Group B) DMBA applications. The activities of antioxidant enzymes glutathione-S transferase (GST), glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) in liver tissue samples taken at 0, 6, 10 and 12 weeks from all groups were assessed. Standard histological examination of skin demonstrated a beneficial action of saffron in mice where saffron treatments were given both before and after the induction of skin carcinogenesis. Saffron ingestion inhibited the formation of skin papillomas in animals and simultaneously reduced their size. In conclusion, saffron inhibits DMBA-induced skin carcinoma in mice when treated early. This may be due, at least in part, to the induction of cellular defense systems.

Diallyl trisulfide induces Bcl-2 and caspase-3-dependent apoptosis via downregulation of Akt phosphorylation in human T24 bladder cancer cells

It is well known that the garlic-derived organosulfur compounds (OSCs) are effective to inhibit a variety of human cancers such as prostate, breast, colon, skin, lung, and bladder cancers. Herein, the pro-apoptotic effects of diallyl trisulfide (DATS), one of garlic-derived OSCs, on T24 bladder cancer cells were investigated. The results demonstrated that DATS suppressed proliferation of T24 bladder cancer cells in a dose- and time-dependent manner which was associated with induced G2/M Phase cell cycle arrest and apoptosis. Mechanistically, DATS inhibits phosphatidylinositol 3'-kinase/Akt activation that, in turn, results in modulation of Bcl-2 family proteins, leading to enhanced apoptosis of T24 cells. These findings suggest that DATS may be an effective way for treating human bladder and other types of cancers.