Modulation of carcinogen metabolism by nitric oxide-aspirin 2 is associated with suppression of DNA damage and DNA adduct formation

The Improvement of the Adaptation Process of Tocopherol and Acetylsalicylic Acid in Offspring of Mothers Exposed to TCDD

Simple Summary

Dioxins are proinflammatory factors that may be transferred to offspring through the placenta during pregnancy. α-tocopherol and acetylsalicylic acid are popular agents that limit the spread of inflammation. A histopathological and biochemical analysis was performed to reveal possible changes in liver and blood plasma in response to dioxins, α-tocopherol, and acetylsalicylic acid. The conducted research demonstrated the presence of negative effects on the liver morphology and blood plasma proteins of offspring, due to dioxins that were derived from the mother. However, the use of both drugs can significantly reduce the negative effects on offspring whose mothers have been treated with dioxins.

Abstract

Dioxins are chemical compounds that may cause an inflammatory reaction. During dioxin-induced inflammation, generated reactive oxygen species lead to morphological changes in various tissues and in biochemical parameters. The aim of this study was to demonstrate the changes in the livers of rats whose mothers were exposed to dioxins and the protective role of α-tocopherol and acetylsalicylic acid in liver inflammation. The study material consisted of Buffalo rats who were the offspring of females treated with dioxin, dioxin + α-tocopherol, or dioxin + acetylsalicylic acid. Livers and blood samples were taken from the rats’ offspring, and then histopathological and biochemical analyses were performed. The histopathological analysis showed that the changes observed in the livers of neonates were the result of the dioxins derived from their mother. The biochemical analysis showed that the morphological changes in the liver affected its function, which manifested in a higher total protein concentration in the dioxin-treated group, and that the creatinine level in this group was significantly higher than that in the other groups. This effect was reduced by the protective role of α-tocopherol and acetylsalicylic acid. Based on these results, we came to the conclusion that dioxins significantly affect the structure of the liver, which negatively affects its function, mainly in the scope of the metabolism of plasma proteins and hepatic enzymes.

NSAIDs: Old Acquaintance in the Pipeline for Cancer Treatment and Prevention─Structural Modulation, Mechanisms of Action, and Bright Future

The limitations of current chemotherapeutic drugs are still a major issue in cancer treatment. Thus, targeted multimodal therapeutic approaches need to be strategically developed to successfully control tumor growth and prevent metastatic burden. Inflammation has long been recognized as a hallmark of cancer and plays a key role in the tumorigenesis and progression of the disease. Several epidemiological, clinical, and preclinical studies have shown that traditional nonsteroidal anti-inflammatory drugs (NSAIDs) exhibit anticancer activities. This Perspective reports the most recent outcomes for the treatment and prevention of different types of cancers for several NSAIDs alone or in combination with current chemotherapeutic drugs. Furthermore, an extensive review of the most promising structural modifications is reported, such as phospho, H₂S, and NO releasing-, selenium-, metal complex-, and natural product-NSAIDs, among others. We also provide a perspective about the new strategies used to obtain more efficient NSAID- or NSAID derivative- formulations for targeted delivery.

Nitric oxide-donating aspirin (NO-Aspirin) suppresses lung tumorigenesis in vitro and in vivo and these effects are associated with modulation of the EGFR signaling pathway

Although regular aspirin use has been shown to lower the risk of colorectal cancer, its efficacy against lung cancer is weak or inconsistent. Moreover, aspirin use increases the risk of ulcers and stomach bleeding. In this study, we determined the efficacy of nitric oxide-donating aspirin (NO-Aspirin), a safer form of aspirin in which the parent drug is linked to a nitric oxide-releasing moiety through a spacer, to suppress lung tumorigenesis. Under in vitro conditions, NO-Aspirin significantly reduced the proliferation and survival of tumorigenic bronchial cell line (1170) and non-small cell lung cancer (NSCLC) cell lines (A549, H1650, H1975 and HCC827) and colony formation by NSCLC cells at sub- or low micromolar concentrations (≤1 µM for 1170 cells and ≤6 µM for NSCLC cells) in a COX-2 independent manner. These effects were paralleled by suppression of phospho-epidermal growth factor receptor (EGFR), -STAT3, -Akt and -ERK and enhanced caspase 3 and PARP cleavage. Among NSCLC cells, EGFR mutant cells (H1650, H1975 and HCC827) were more sensitive than cells expressing wild-type EGFR (A549) and H1650 cells were the most sensitive. Moreover, NO-Aspirin sensitized H1650 and H1975 cells to the antiproliferative effects of erlotinib, a tyrosine kinase inhibitor. In in vivo studies using 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) + lipopolysaccharide (LPS)-induced model of lung tumorigenesis, NO-Aspirin significantly reduced the number and size of lung tumors, expression of phospho-EGFR and -Akt as well as the pro-inflammatory molecules TNF-α and interferon-gamma. Overall, these results indicate the potential of NO-Aspirin for the chemoprevention of lung cancer in high risk populations.

Indirect study of the effect of α-tocopherol and acetylsalicylic acid on the mineral composition of bone tissue in the offspring of female rats treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin: long-term observations

This paper discusses problems related to the influence of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the mineral composition of the calvaria in the offspring of female rats.

Aspirin abrogates impairment of mammary gland differentiation induced by early in life second-hand smoke in mice

Epidemiological studies show that there is limited evidence that tobacco smoking causes breast cancer in humans. In rodents, many tobacco smoke chemicals cause mammary gland tumors. This study evaluated the mammary gland differentiation in mice exposed to environmental cigarette smoke (ECS), using 3R4F Kentucky reference cigarettes, starting after birth and continuing daily for 10 weeks (total particulate exposure 95 mg/m3; CO 610 ppm). We also analyzed the effects of oral administration of non-steroidal anti-inflammatory drugs (NSAIDs), aspirin (1600 mg/kg) or naproxen (320 mg/kg), on mammary gland differentiation, either in unexposed or ECS-exposed mice. The ECS exposure caused delay of mammary glands development. We speculate that this delay may result from aryl hydrocarbon receptor (AHR) signaling activation, which has an antiestrogenic effect and crosstalk to the estrogen metabolism pathway. Similarly, naproxen impaired gland differentiation in unexposed and ECS-exposed mice, while aspirin hindered its development only in unexposed mice. The lack of differentiation induced by the NSAIDs could be explained by their antiestrogenic effect through inhibition of aldo-keto reductases. In ECS-exposed animals, aspirin induced intense lobular formation, which could indicate that aspirin is counteracting the AHR signaling induced by ECS. Based on the differentiation induced by aspirin in ECS-exposed animals, we postulate that these mice would be less susceptible to mammary carcinogenesis. Our results suggest that exposure to smoke at an early age impairs the development of the mammary gland, thus resulting in a longer period of susceptibility and increased risk of breast cancer. However, addition of aspirin can abrogate this effect.

Estimated dietary intake and risk assessment of polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like polychlorinated biphenyls from fish consumption in the Korean general population

We analyzed 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and 12 dioxin-like polychlorinated biphenyls (DL-PCBs) in samples from various fish species available at food markets in nine Korean cities. The estimated dietary intake of these chemicals was calculated from the raw concentrations of PCDD/Fs and DL-PCBs in each sample and from the food consumption of the Korean general population, and a comparison was made with the provisional tolerable monthly intake (PTMI). The average daily dietary exposure and the 95th percentile of intake of PCDD/Fs and DL-PCBs were 0.21 and 0.49 pg WHO05-toxic equivalents (TEQ) kg(-1) body weight d(-1) representing 5.27% and 12.26%, respectively, of the Korean tolerable daily intake (TDI). We applied the monthly fish consumption limits to the evaluation of improved risk assessment and concluded that unlimited consumption of most fish species does not contribute to the elevated cancer risk. This investigation was the first such large-scale study in Korea, and incorporated 37 species, including a species of whale, and 480 samples. The major aims of this study were to demonstrate the health risks associated with fish intake and to ensure food safety through total analysis of PCDD/Fs and DL-PCBs using gas chromatography/high-resolution mass spectrometry (GC-HRMS).

Transport, metabolism, and endosomal trafficking-dependent regulation of intestinal fructose absorption

Dietary fructose that is linked to metabolic abnormalities can up-regulate its own absorption, but the underlying regulatory mechanisms are not known. We hypothesized that glucose transporter (GLUT) protein, member 5 (GLUT5) is the primary fructose transporter and that fructose absorption via GLUT5, metabolism via ketohexokinase (KHK), as well as GLUT5 trafficking to the apical membrane via the Ras-related protein-in-brain 11 (Rab11)a-dependent endosomes are each required for regulation. Introducing fructose but not lysine and glucose solutions into the lumen increased by 2- to 10-fold the heterogeneous nuclear RNA, mRNA, protein, and activity levels of GLUT5 in adult wild-type mice consuming chow. Levels of GLUT5 were >100-fold that of candidate apical fructose transporters GLUTs 7, 8, and 12 whose expression, and that of GLUT 2 and the sodium-dependent glucose transporter protein 1 (SGLT1), was not regulated by luminal fructose. GLUT5-knockout (KO) mice exhibited no facilitative fructose transport and no compensatory increases in activity and expression of SGLT1 and other GLUTs. Fructose could not up-regulate GLUT5 in GLUT5-KO, KHK-KO, and intestinal epithelial cell-specific Rab11a-KO mice. The fructose-specific metabolite glyceraldehyde did not increase GLUT5 expression. GLUT5 is the primary transporter responsible for facilitative absorption of fructose, and its regulation specifically requires fructose uptake and metabolism and normal GLUT5 trafficking to the apical membrane.

Histopathological, ultrastructural, and immunohistochemical assessment of hippocampus structures of rats exposed to TCDD and high doses of tocopherol and acetylsalicylic acid

The effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on central nervous system consists of changing expression of estrogen receptors, whereas the result of chronic inflammatory reaction caused by dioxin is occurrence of destructive changes in various organs connected with disturbed metabolism of connective tissue and damage of cells. The aim of the study was to determine the effect of dioxins on function, ultrastructure, and cytological and histological structure of hippocampus, particularly on expression of estrogen receptors in central nervous system as well as to define protective influence of tocopherol (TCP) and acetylsalicylic acid (ASA) on the decrease in activity of proinflammatory effects in central nervous system. It was shown that TCDD contributes to destructive and inflammatory changes along with demyelization of myelin sheaths and atrophy of estrogen receptors in hippocampus. Dioxin contributes to atrophy of estrogen receptors in hippocampus, in which also destructive and inflammatory changes were found along with demyelination of myelin sheaths. Histopathological and ultrastructural image of hippocampus areas in rats, in which both TCP and ASA were used, is characterized by poorly expressed degenerative changes and smaller inflammatory reactivity. Using both TCP and ASA has a protective effect on functions of central nervous system.

The influence of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on hematological parameters during experimentally induced pleuritis in rats

Proper functioning of homeostatic mechanisms is characteristic for every healthy organism and enables adapting to environmental changes. These complicated systematic reactions can neutralize the harmful stress factors leading to various inflammatory reactions. The aim of this study was to determine dynamic changes in the inflammatory reaction after single 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) administration of 5 μg/kg body weight into rats with experimentally induced pleuritis. These changes were observed by monitoring the hematological blood parameters during inflammation. The obtained results proved that dioxins contribute to various changes in the character of the inflammatory response. TCDD administration before pleuritis initiation caused an increase of lymphocytes and significant decrease of the number of neutrophils during inflammation. The current study proved that administration of low TCDD dose (seven times lower than used in other studies) can cause thymus, spleen, or lymphatic gland atrophy. This finding indicates the toxic influence of small TCDD dose especially on the immune system.

Quinone-induced activation of Keap1/Nrf2 signaling by aspirin prodrugs masquerading as nitric oxide

The promising therapeutic potential of the NO-donating hybrid aspirin prodrugs (NO-ASA) includes induction of chemopreventive mechanisms and has been reported in almost 100 publications. One example, NCX-4040 (pNO-ASA), is bioactivated by esterase to a quinone methide (QM) electrophile. In cell cultures, pNO-ASA and QM-donating X-ASA prodrugs that cannot release NO rapidly depleted intracellular GSH and caused DNA damage; however, induction of Nrf2 signaling elicited cellular defense mechanisms including upregulation of NAD(P)H:quinone oxidoreductase-1 (NQO1) and glutamate-cysteine ligase (GCL). In HepG2 cells, the "NO-specific" 4,5-diaminofluorescein reporter, DAF-DA, responded to NO-ASA and X-ASA, with QM-induced oxidative stress masquerading as NO. LC-MS/MS analysis demonstrated efficient alkylation of Cys residues of proteins including glutathione-S-transferase-P1 (GST-P1) and Kelch-like ECH-associated protein 1 (Keap1). Evidence was obtained for alkylation of Keap1 Cys residues associated with Nrf2 translocation to the nucleus, nuclear translocation of Nrf2, activation of antioxidant response element (ARE), and upregulation of cytoprotective target genes. At least in cell culture, pNO-ASA acts as a QM donor, bioactivated by cellular esterase activity to release salicylates, NO(3)(-), and an electrophilic QM. Finally, two novel aspirin prodrugs were synthesized, both potent activators of ARE, designed to release only the QM and salicylates on bioactivation. Current interest in electrophilic drugs acting via Nrf2 signaling suggests that QM-donating hybrid drugs can be designed as informative chemical probes in drug discovery.

Acetylsalicylic acid-induced oxidative stress, cell cycle arrest, apoptosis and mitochondrial dysfunction in human hepatoma HepG2 cells

It is widely accepted that non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin, reduce the risk of cancer. The anti-cancer and anti-inflammatory effects of NSAIDs are associated with the inhibition of prostaglandin synthesis and cyclooxygenase-2 activity. Several other mechanisms which contribute to the anti-cancer effect of these drugs in different cancer models both in vivo and in vitro are also presumed to be involved. The precise molecular mechanism, however, is still not clear. We investigated, therefore, the effects of acetylsalicylic acid (ASA, aspirin) on multiple cellular and functional targets, including mitochondrial bioenergetics, using human hepatoma HepG2 cancer cells in culture. Our results demonstrate that ASA induced G0/G1 cell cycle arrest and apoptosis in HepG2 cells. ASA increased the production of reactive oxygen species, reduced the cellular glutathione (GSH) pool and inhibited the activities of the mitochondrial respiratory enzyme complexes, NADH-ubiquinone oxidoreductase (complex I), cytochrome c oxidase (complex IV) and the mitochondrial matrix enzyme, aconitase. Apoptosis was triggered by alteration in mitochondrial permeability transition, inhibition of ATP synthesis, decreased expression of the anti-apoptotic protein Bcl-2, release of cytochrome c and activation of pro-apoptotic caspase-3 and the DNA repairing enzyme, poly (-ADP-ribose) polymerase (PARP). These findings strongly suggest that ASA-induced toxicity in human hepatoma HepG2 cells is mediated by increased metabolic and oxidative stress, accompanied by mitochondrial dysfunction which result in apoptosis.

Induction of cytochromes P450 1A1 and 1A2 by tanshinones in human HepG2 hepatoma cell line

Diterpenoid tanshinones including tanshinone IIA (TIIA), cryptotanshinone (CTS), tanshinone I (TI) and dihydrotanshinone I (DHTI) are the major bioactive components from Danshen. The major aim of our present study was to investigate the induction potential of these four main components of tanshinones (TIIA, CTS, TI, and DHTI) on the expression of CYP1A1 and CYP1A2 in HepG2 cells. Our results showed that all of these four tanshinones caused a significant time- and concentration-dependent increase in the amount of CYP1A1/2 expression in HepG2 cells. These induction effects were further characterized through transcriptional regulation: the induction of CYP1A1/2 mRNA level by tanshinones was completely blocked by the transcription inhibitor actinomycin D; the expression of CYP1A1/2 heterogeneous nuclear RNA was induced by tanshinone treatment; and CYP1A1 mRNA stability was not influenced by these tanshinones. Interestingly, tanshinones plus B[a]P produced additive/synergistic effect on CYP1A1/2 induction. In addition, the tanshinone-induced CYP1A1/2 expression was abolished by the aryl hydrocarbon receptor (AhR) antagonist resveratrol, suggesting an AhR dependent transcription mechanism. In the reporter gene assay, while TI and DHTI significantly induced AhR-dependent luciferase activity, TIIA and CTS failed to induce this activity. Collectively, the tanshinones could induce CYP1A1 and CYP1A2 expression through transcriptional activation mechanism and exert differential effects on activating AhR in HepG2 cells. Our findings suggest that rational administration of tanshinones should be considered with respect to their effect on AhR and CYP1A1/2 expression.

Modulation of stress genes expression profile by nitric oxide-releasing aspirin in Jurkat T leukemia cells

NO-donating aspirin (NO-ASA, para isomer) has been reported to exhibit strong growth inhibitory effect in Jurkat T-acute lymphoblastic leukemia (T-ALL) cells mediated in part by beta-catenin degradation and caspase activation, but the mechanism(s) still remains unclear. In this study, DNA oligoarrays with 263 genes were used to examine the gene expression profiles relating to stress and drug metabolism, and characterize the stress responses at IC(50) and subIC(50) concentrations of p-NO-ASA (20 and 10microM, respectively) in Jurkat T cells. A total of 22 genes related to heat shock response, apoptosis signaling, detoxifiers and Phase II enzymes, and regulators of cell growth were altered in expression by array analysis based on the expression fold change criteria of > or =1.5-fold or < or =0.65-fold. Real time quantitative RT-PCR confirmed that 20microM p-NO-ASA strongly upregulated the mRNA levels of two heat shock genes HSPA1A (41.5+/-7.01-fold) and HSPA6 (100.4+/-8.11-fold), and FOS (16.2+/-3.2-fold), moderately upregulated HSPH1 (1.71+/-0.43-fold), FMO4 (4.5+/-1.67-fold), CASP9 (1.77+/-0.03-fold), DDIT3 (5.6+/-0.51-fold), and downregulated NF-kappaB1 (0.54+/-0.01-fold) and CCND1 (0.69+/-0.06-fold). Protein levels of Hsp70, the product of HSPA1A, and fos were increased in p-NO-ASA-treated Jurkat T and HT-29 colon cancer cells in a dose-dependent manner. Silencing of Hsp70 enhanced the growth inhibitory effect of p-NO-ASA at low concentrations. The altered gene expression patterns by NO-ASA in Jurkat T cells suggest mechanisms for carcinogen metabolism, anti-proliferative activity and possible chemoprotective activity in T-ALL.