Involvement of NADPH oxidases in suppression of cyclooxygenase-2 promoter-dependent transcriptional activities by sesamol

Sesamol Upregulates Death Receptors and Acts as a Chemosensitizer in Solid Ehrlich Carcinoma Model in Mice

AIMS

The aim of the present study was to investigate the anti-tumor effect of sesamol (SML), a nutritional phenolic compound of sesame, in solid Ehrlich carcinoma (SEC) model in mice and its ability to enhance doxorubicin (DOX) anti-tumor activity. Moreover, we analyzed the ability of SML to protect against DOX-induced cardiotoxicity.

MAIN METHODS

SML (70 mg/kg), DOX (2 mg/kg) and their combination were given to mice bearing SEC for 21 day. The mRNA level of Fas, FasL, TRAILR2, TRAIL, caspase-3 and Bcl-2 were assessed by qPCR. Tumor and cardiac tissues were examined for histopathological changes by hematoxylin and eosin. Active caspase-3 was scored by immunohistochemical analysis.

KEY FINDINGS

SML treatment significantly decreased solid tumor size and weight. In addition, SML enhanced DOX anti-tumor activity. SML treatment either alone or in combination with DOX induced upregulation of Fas/FasL and TRAILR2/TRAIL gene expression. Moreover, SML increased caspase-3 protein and gene expressions and decreased Bcl-2 gene expression.

SIGNIFICANCE

SML upregulates death receptors expression and enhances apoptosis induction in tumor cells that may explain its anti-tumor activity. Not only that, but SML also enhances DOX anti-tumor activity and attenuates its cardiotoxicity.

DUOX2, a common modulator in preventive effects of monoamine-based antidepressants on water immersion restraint stress- and indomethacin- induced gastric mucosal damage

Multiple kinds of monoamine-based antidepressants have been shown prophylactic effects in experimentally induced gastric ulcer. The loss of redox homeostasis plays a principle role in the development of peptic mucosal damage. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases are one of the most important sources of reactive oxygen species within the gastrointestinal tract. It is unclear whether there are some common NADPH oxidases modulated by monoamine-based antidepressants in different gastric mucosal damage models. We explored the effects of selective serotonin-norepinephrine reuptake inhibitor (SNRI) duloxetine on the reactive oxygen species production and antioxidant capacity in the gastric mucosa of water immersion restraint (WIRS) or indomethacin treated rats, and examined the role of NADPH oxidases in the protective effects. Pretreated duloxetine prevented the increase of gastric mucosal NADPH oxidase activity and NADPH oxidase inhibitor apocynin dose-dependently protected gastric mucosa from damage by the two factors. Furthermore, dual oxidase 2 (DUOX2) and NADPH oxidase4 (NOX4) are involved in the protective effects of duloxetine in both models. We then examined NADPH oxidases expression modulated by the other monoamine-based antidepressants including selective serotonin reuptake inhibitor (SSRIs) fluoxetine, tricyclic agent (TCAs) amitriptyline and monoamine oxidase inhibitor (MAOs) moclobemide in the two models, and all the three antidepressants reduced the DUOX2 expression in the gastric mucosa. So DUOX2 was a common modulator in the preventive effects of all the monoamine-based antidepressants on WIRS- and indomethacin-induced gastric lesion. Our work provided a peripheral joint molecular target for monoamine modulatory antidepressants, which may be helpful to reveal the mechanisms of this kind of drugs more than monoamine regulation.

Sesamol, a major lignan in sesame seeds (Sesamum indicum): Anti-cancer properties and mechanisms of action

Sesamol is a natural phenolic compound and a major lignan isolated from sesame seeds (Sesamum indicum) and sesame oil. The therapeutic potential of sesamol was investigated intensively, and there is compelling evidence that sesamol acts as a metabolic regulator that possesses antioxidant, anti-mutagenic, anti-hepatotoxic, anti-inflammatory, anti-aging, and chemopreventive properties. Various studies have reported that sesamol exerts potent anti-cancer effects. Herein, we provide a comprehensive review that summarizes the in vitro and in vivo anti-cancer activity of sesamol in several cancer cell lines and animal models. The protective role that sesamol plays against oxidative stress through its radical scavenging ability and lipid peroxidation lowering potential is analyzed. The ability of sesamol to regulate apoptosis and various stages of the cell cycle is also outlined. Moreover, the signaling pathways that sesamol seems to target to execute its antioxidant, anti-inflammatory, and pro-apoptotic/anti-proliferative roles are discussed. The signaling pathways that sesamol targets include the p53, MAPK, JNK, PI3K/AKT, TNFα, NF-κB, PPARγ, caspase-3, Nrf2, eNOS, and LOX pathways. The mechanisms of action that sesamol executes to deliver its anti-cancer effects are delineated. In sum, there is ample evidence suggesting that sesamol possesses potent anti-cancer properties in vitro and in vivo. A thorough understanding of the molecular targets of sesamol and the mechanisms of action underlying its anti-cancer effects is necessary for possible employment of sesamol as a chemotherapeutic agent in cancer prevention and therapy.

Plasma metabolite abundances are associated with urinary enterolactone excretion in healthy participants on controlled diets

Enterolignans, products of gut bacterial metabolism of plant lignans, have been associated with reduced risk of chronic diseases, but their association with other plasma metabolites is unknown. We examined plasma metabolite profiles according to urinary enterolignan excretion in a cross-sectional analysis using data from a randomized crossover, controlled feeding study. Eighty healthy adult males and females completed two 28-day feeding periods differing by glycemic load, refined carbohydrate, and fiber content. Lignan intake was calculated from food records using a polyphenol database. Targeted metabolomics was performed by LC-MS on plasma from fasting blood samples collected at the end of each feeding period. Enterolactone (ENL) and enterodiol, were measured in 24 h urine samples collected on the penultimate day of each study period using GC-MS. Linear mixed models were used to test the association between enterolignan excretion and metabolite abundances. Pathway analyses were conducted using the Global Test. Benjamini-Hochberg false discovery rate (FDR) was used to control for multiple testing. Of the metabolites assayed, 121 were detected in all samples. ENL excretion was associated positively with plasma hippuric acid and melatonin, and inversely with epinephrine, creatine, glycochenodeoxycholate, and glyceraldehyde (P < 0.05). Hippuric acid only satisfied the FDR of q < 0.1. END excretion was associated with myristic acid and glycine (q < 0.5). Two of 57 pathways tested were associated significantly with ENL, ubiquinone and terpenoid-quinone biosynthesis, and inositol phosphate metabolism. These results suggest a potential role for ENL or ENL-metabolizing gut bacteria in regulating plasma metabolites.

Sesamol Induces Human Hepatocellular Carcinoma Cells Apoptosis by Impairing Mitochondrial Function and Suppressing Autophagy

Sesamol, a nutritional phenolic antioxidant compound enriched in sesame seeds, has been shown to have potential anticancer activities. This study aims at characterizing the antitumor efficacy of sesamol and unveiling the importance of mitochondria in sesamol-induced effects using a human hepatocellular carcinoma cell line, HepG2 cells. Results of this study showed that sesamol treatment suppressed colony formation, elicited S phase arrest during cell cycle progression, and induced both intrinsic and extrinsic apoptotic pathway in vitro with a dose-dependent manner. Furthermore, sesamol treatment elicited mitochondrial dysfunction by inducing a loss of mitochondrial membrane potential. Impaired mitochondria and accumulated H2O2 production resulted in disturbance of redox-sensitive signaling including Akt and MAPKs pathways. Mitochondrial biogenesis was inhibited as suggested by the decline in expression of mitochondrial complex I subunit ND1, and the upstream AMPK/PGC1α signals. Importantly, sesamol inhibited mitophagy and autophagy through impeding the PI3K Class III/Belin-1 pathway. Autophagy stimulator rapamycin reversed sesamol-induced apoptosis and mitochondrial respiration disorders. Moreover, it was also shown that sesamol has potent anti-hepatoma activity in a xenograft nude mice model. These data suggest that mitochondria play an essential role in sesamol-induced HepG2 cells death, and further research targeting mitochondria will provide more chemotherapeutic opportunities.

Endogenous conversion of ω-6 to ω-3 polyunsaturated fatty acids in fat-1 mice attenuated intestinal polyposis by either inhibiting COX-2/β-catenin signaling or activating 15-PGDH/IL-18

Omega-3 polyunsaturated fatty acids (ω-3PUFAs) have inhibitory effects in various preclinical cancer models, but their effects in intestinal polyposis have never been examined. As attempts have been made to use nutritional intervention to counteract colon cancer development, in this study we evaluated the effects of ω-3 PUFAs on intestinal polyposis in the Apc(Min/+) mouse model. The experimental groups included wild-type C56BL/6 mice, Apc(Min/+) mice, fat-1 transgenic mice expressing an n-3 desaturase to enable ω-3 PUFA synthesis, and Apc(Min/+) × fat-1 double-transgenic mice; all mice were 20 weeks of age. Small intestines were collected for gross and pathologic evaluation, including assessment of polyp number and size, followed by immunohistochemical staining and Western blotting. After administration of various concentrations of ω-3 PUFAs, PUFA levels were measured in small intestine tissue by GC/MS/MS analysis to compare with PUFA synthesis of between C57BL6 and fat-1mice. As a result, ω-3 PUFAs significantly attenuated Apc mutation-induced intestinal polyposis accompanied with significant inhibition of Wnt/β-catenin signaling, COX-2 and PGE2, but induced significant levels of 15-PGDH. In addition, significant induction of the inflammasome-related substrates as IL-1β and IL-18 and activation of caspase-1 was observed in Apc(Min/+) × fat-1 mice. Administration of at least 3 g/60 kg ω-3 PUFAs was equivalent to ω-3 PUFAs produced in fat-1 mice and resulted in significant increase in the expression of IL-1β, caspase-3 and IL-18, as seen in Apc(Min/+) × fat-1 mice. We conclude that ω-3PUFAs can prevent intestinal polyp formation by inhibition of Wnt/β-catenin signaling, but increased levels of 15-PGDH and IL-18.