Anethole dithiolethione regulates oxidant-induced tyrosine kinase activation in endothelial cells

Trans-anethole pretreatment ameliorates hepatic ischemia-reperfusion injury via regulation of soluble epoxide hydrolase

Hepatic ischemia reperfusion injury (IRI) is a risk factor for early graft nonfunction and graft rejection after liver transplantation (LT). The process of liver IRI involves inflammatory response, oxidative stress, apoptosis and other pathophysiological processes. So far, there is still a lack of effective drugs to ameliorate liver IRI. Trans-anethole (TA) is an aromatic compound. Many medications as well as natural foods contain TA. TA has multiple effects such as anti-inflammation, anti-oxidative stress and anti-apoptosis. However, the mechanism of TA pretreatment in liver IRI is unclear. The mice hepatic IRI model was constructed after gavage pretreatment with TA (10 mg/kg, 20 mg/kg, 40 mg/kg) for 7 consecutive days. Our study confirmed that TA pretreatment significantly improve liver function and reduce serum AST, ALT in hepatic IRI. HE staining showed that TA pretreatment alleviated liver injury. Meanwhile, TA (20 mg/kg) pretreatment attenuated hepatocyte apoptosis in hepatic IRI. In addition, TA (20 mg/kg) pretreatment reduced the inflammatory factors TNF-α, IL-6 and infiltration of CD11b positive cells in liver tissues during hepatic IRI in mice. TA pretreatment also alleviated oxidative stress in mice hepatic IRI. Our study further indicated that TA pretreatment attenuated mice hepatic IRI through inhibiting NLRP3 inflammasome activation via regulation of soluble epoxide hydrolase (sEH). This study provides a novel and effective potential drug with few side effects for easing liver IRI.

Anethole induces anti-oral cancer activity by triggering apoptosis, autophagy and oxidative stress and by modulation of multiple signaling pathways

Oral cancer is one of the major public health problems. The aim of this study was to evaluate the effects of anethole, 1-methoxy-4-[(E)-1-propenyl]-benzene, on growth and apoptosis of oral tumor cells, and to identify the signaling pathways involved in its interaction with these cancer cells. Cancer gingival cells (Ca9-22) were treated with different concentrations of anethole. Cell proliferation and cytotoxic effects were measured by MTT and LDH assays. Cell death, autophagy and oxidative stress markers were assessed by flow cytometry while cell migration was determined by a healing capacity assay. The effect of anethole on apoptotic and pro-carcinogenic signaling pathways proteins was assessed by immunoblotting. Our results showed that anethole selectively and in a dose-dependent manner decreases the cell proliferation rate, and conversely induces toxicity and apoptosis in oral cancer cells. This killing effect was mediated mainly through NF-κB, MAPKinases, Wnt, caspase 3, 9 and PARP1 pathways. Anethole showed an ability to induce autophagy, decrease reactive oxygen species (ROS) production and increased intracellular glutathione (GSH) activity. Finally, anethole treatment inhibits the expression of oncogenes (cyclin D1) and up-regulated cyclin-dependent kinase inhibitor (p21^WAF1), increases the expression of p53 gene, but inhibits the epithelial-mesenchymal transition markers. These results indicate that anethole could be a potential molecule for the therapy of oral cancer.

An old medicine as a new drug to prevent mitochondrial complex I from producing oxygen radicals

Findings

Here, we demonstrate that OP2113 (5-(4-Methoxyphenyl)-3H-1,2-dithiole-3-thione, CAS 532-11-6), synthesized and used as a drug since 1696, does not act as an unspecific antioxidant molecule (i.e., as a radical scavenger) but unexpectedly decreases mitochondrial reactive oxygen species (ROS/H₂O₂) production by acting as a specific inhibitor of ROS production at the I_Q site of complex I of the mitochondrial respiratory chain. Studies performed on isolated rat heart mitochondria also showed that OP2113 does not affect oxidative phosphorylation driven by complex I or complex II substrates. We assessed the effect of OP2113 on an infarct model of ex vivo rat heart in which mitochondrial ROS production is highly involved and showed that OP2113 protects heart tissue as well as the recovery of heart contractile activity.

Conclusion / Significance

This work represents the first demonstration of a drug authorized for use in humans that can prevent mitochondria from producing ROS/H₂O₂. OP2113 therefore appears to be a member of the new class of mitochondrial ROS blockers (S1QELs) and could protect mitochondrial function in numerous diseases in which ROS-induced mitochondrial dysfunction occurs. These applications include but are not limited to aging, Parkinson’s and Alzheimer's diseases, cardiac atrial fibrillation, and ischemia-reperfusion injury.

Xanthine Oxidase-Derived ROS Display a Biphasic Effect on Endothelial Cells Adhesion and FAK Phosphorylation

In pathological situations such as ischemia-reperfusion and acute respiratory distress syndrome, reactive oxygen species (ROS) are produced by different systems which are involved in endothelial cells injury, ultimately leading to severe organ dysfunctions. The aim of this work was to study the effect of ROS produced by hypoxanthine-xanthine oxidase (Hx-XO) on the adhesion of human umbilical vein endothelial cells (HUVEC) and on the signaling pathways involved. Results show that Hx-XO-derived ROS induced an increase in HUVEC adhesion in the early stages of the process (less than 30 min), followed by a decrease in adhesion in the later stages of the process. Interestingly, Hx-XO-derived ROS induced the same biphasic effect on the phosphorylation of the focal adhesion kinase (FAK), a nonreceptor tyrosine kinase critical for cell adhesion, but not on ERK1/2 phosphorylation. The biphasic effect was not seen with ERK1/2 where a decrease in phosphorylation only was observed. Wortmannin, a PI3-kinase inhibitor, inhibited ROS-induced cell adhesion and FAK phosphorylation. Orthovanadate, a protein tyrosine phosphatase inhibitor, and Resveratrol (Resv), an antioxidant agent, protected FAK and ERK1/2 from dephosphorylation and HUVEC from ROS-induced loss of adhesion. This study shows that ROS could have both stimulatory and inhibitory effects on HUVEC adhesion and FAK phosphorylation and suggests that PI3-kinase and tyrosine phosphatase control these effects.

Control of oxidative posttranslational cysteine modifications: from intricate chemistry to widespread biological and medical applications

Cysteine residues in proteins and enzymes often fulfill rather important roles, particularly in the context of cellular signaling, protein-protein interactions, substrate and metal binding, and catalysis. At the same time, some of the most active cysteine residues are also quite sensitive toward (oxidative) modification. S-Thiolation, S-nitrosation, and disulfide bond and sulfenic acid formation are processes which occur frequently inside the cell and regulate the function and activity of many proteins and enzymes. During oxidative stress, such modifications trigger, among others, antioxidant responses and cell death. The unique combination of nonredox function on the one hand and participation in redox signaling and control on the other has placed many cysteine proteins at the center of drug design and pesticide development. Research during the past decade has identified a range of chemically rather interesting, biologically very active substances that are able to modify cysteine residues in such proteins with huge efficiency, yet also considerable selectivity. These agents are often based on natural products and range from simple disulfides to complex polysulfanes, tetrahydrothienopyridines, α,β -unsaturated disulfides, thiuramdisulfides, and 1,2-dithiole-3-thiones. At the same time, inhibition of enzymes responsible for posttranslational cysteine modifications (and their removal) has become an important area of innovative drug research. Such investigations into the control of the cellular thiolstat by thiol-selective agents cross many disciplines and are often far from trivial.

Modulation of angiogenesis by dithiolethione-modified NSAIDs and valproic acid

BACKGROUND AND PURPOSE

Angiogenesis involves multiple signaling pathways that must be considered when developing agents to modulate pathological angiogenesis. Because both cyclooxygenase inhibitors and dithioles have demonstrated anti-angiogenic properties, we investigated the activities of a new class of anti-inflammatory drugs containing dithiolethione moieties (S-NSAIDs) and S-valproate.

EXPERIMENTAL APPROACH

Anti-angiogenic activities of S-NSAIDS, S-valproate, and the respective parent compounds were assessed using umbilical vein endothelial cells, muscle and tumor tissue explant angiogenesis assays, and developmental angiogenesis in Fli:EGFP transgenic zebrafish embryos.

KEY RESULTS

Dithiolethione derivatives of diclofenac, valproate, and sulindac inhibited endothelial cell proliferation and induced Ser(78) phosphorylation of hsp27, a known molecular target of anti-angiogenic signaling. The parent drugs lacked this activity, but dithiolethiones were active at comparable concentrations. Although dithiolethiones can potentially release hydrogen sulphide, NaSH did not reproduce some activities of the S-NSAIDs, indicating that the dithioles regulate angiogenesis through mechanisms other than release of H(2)S. In contrast to the parent drugs, S-NSAIDs, S-valproate, NaSH, and dithiolethiones were potent inhibitors of angiogenic responses in muscle and HT29 tumor explants assessed by 3-dimensional collagen matrix assays. Dithiolethiones and valproic acid were also potent inhibitors of developmental angiogenesis in zebrafish embryos, but the S-NSAIDs, remarkably, lacked this activity.

CONCLUSIONS AND IMPLICATION

S-NSAIDs and S-valproate have potent anti-angiogenic activities mediated by their dithiole moieties. The novel properties of S-NSAIDs and S-valproate to inhibit pathological versus developmental angiogenesis suggest that these agents may have a role in cancer treatment.

Resveratrol attenuates oxidative-induced DNA damage in C6 Glioma cells

The antioxidant compound, trans-resveratrol, is found in substantial amounts in several types of red wine and has been proposed to have beneficial effects in brain pathologies that may involve oxidative stress. The objective of the present study was to investigate the genoprotective effects of resveratrol under conditions of oxidative stress induced by hydrogen peroxide in C6 glioma cells. DNA damage was assessed by the alkaline single-cell gel electrophoresis assay or comet assay. In order to investigate the genoprotective effects of resveratrol against oxidative stress induced by hydrogen peroxide on DNA damage, two models of oxidative stress induction were utilized. (I) 1mM hydrogen peroxide for 0.5h (10-250 microM of resveratrol) and (II) 0.1 or 0.5mM hydrogen peroxide for 6h (10-100 microM of resveratrol). Resveratrol was able to prevent oxidative damage to cellular DNA, induced in model I, at all concentrations tested; however, at 6h of incubation, resveratrol prevented DNA damage only partially. After 6h of incubation (up to 48h) resveratrol per se induced a slight time and dose-dependent DNA damage. In conclusion, these results provide evidence that resveratrol may act as a significantly bioactive compound, supporting the possibility that, due to its antioxidant properties, it may be important in health and disease for protecting against DNA damage through oxidative stress.

Effect of Acori graminei Rhizoma on contractile dysfunction of ischemic and reperfused rat heart

Acori graminei Rhizoma is one of the best-known traditional herbal medicines frequently used for the treatment of cardiovascular symptoms in Asian countries. The anti-ischemic effect of Acori graminei Rhizoma on ischemia-induced isolated rat heart was investigated through analysis of changes in perfusion pressure, aortic flow, coronary flow, and cardiac output. The subjects in this study were divided into two groups, an ischemia-induced group without any treatment (I), and an ischemia-induced group with Acori graminei Rhizoma treatment (I+AGR). There were no significant differences in perfusion pressure, aortic flow, coronary flow, or cardiac output between the two groups before ischemia was induced. The supply of oxygen and buffer was stopped for 10 min to induce ischemia in isolated rat hearts, and Acori graminei Rhizoma was administered while inducing ischemia. The data showed that Acori graminei Rhizoma treatment significantly prevented decreases in perfusion pressure, aortic flow, coronary flow, and cardiac output under an ischemic condition. In addition, hemodynamics (except heart rate) of the AGR-treated group was significantly recovered 60 min after reperfusion compared to the control group, (systolic aortic pressure: 85.5% vs. 62.5%, aortic flow volume: 68.1% vs. 49.4%, coronary flow volume: 86.8% vs. 60.1%, and cardiac output: 73.1% vs. 54.1%, p<0.01). These results suggest that Acori graminei Rhizoma has distinct anti-ischemic effects.

Sjogren's syndrome: evolving therapies

Sjogren's syndrome (keratoconjunctivis sicca) is a relatively common disorder with incidence of approximately 0.5% of adult women. It has both local (ocular and oral) features as well as systemic manifestations. There has been recent FDA approval of agents to stimulate salivation (pilocarpine and cevimeline) and studies are in progress to determine their role in the treatment of dry eye. New therapies are in clinical trials for ocular manifestations with the most interest focused on topical cyclosporin A and purinogenic receptor agonists. In oral therapy, topical human interferon has reported encouraging results in short-term studies. However, the high placebo response (probably reflecting the beneficial response of mechanical stimulation of the buccal mucosa by the lozenge) and the response to much cheaper therapies (such as acid maltose lozenges) may offer safer and cheaper alternatives. For systemic disease, there is interest in tumour necrosis factor inhibitors. However, the cost-effectiveness and safety of biological agents needs longer term follow up, as they appear much less dramatic in their effect on systemic lupus erythematosus or Sjogren's syndrome than in rheumatoid arthritis.