Reactive oxygen species in redox cancer therapy

Dietary phytochemicals and cancer chemoprevention: a review of the clinical evidence

Cancer chemoprevention involves the use of different natural or biologic agents to inhibit or reverse tumor growth. Epidemiological and pre-clinical data suggest that various natural phytochemicals and dietary compounds possess chemopreventive properties, and in-vitro and animal studies support that these compounds may modulate signaling pathways involved in cell proliferation and apoptosis in transformed cells, enhance the host immune system and sensitize malignant cells to cytotoxic agents. Despite promising results from experimental studies, only a limited number of these compounds have been tested in clinical trials and have shown variable results. In this review, we summarize the data regarding select phytochemicals including curcumin, resveratrol, lycopene, folates and tea polyphenols with emphasis on the clinical evidence supporting the efficacy of these compounds in high-risk populations.

PI-103 and Quercetin Attenuate PI3K-AKT Signaling Pathway in T- Cell Lymphoma Exposed to Hydrogen Peroxide

Phosphatidylinositol 3 kinase-protein kinase B (PI3K-AKT) pathway has been considered as major drug target site due to its frequent activation in cancer. AKT regulates the activity of various targets to promote tumorigenesis and metastasis. Accumulation of reactive oxygen species (ROS) has been linked to oxidative stress and regulation of signaling pathways for metabolic adaptation of tumor microenvironment. Hydrogen peroxide (H2O2) in this context is used as ROS source for oxidative stress preconditioning. Antioxidants are commonly considered to be beneficial to reduce detrimental effects of ROS and are recommended as dietary supplements. Quercetin, a ubiquitous bioactive flavonoid is a dietary component which has attracted much of interest due to its potential health-promoting effects. Present study is aimed to analyze PI3K-AKT signaling pathway in H2O2 exposed Dalton's lymphoma ascite (DLA) cells. Further, regulation of PI3K-AKT pathway by quercetin as well as PI-103, an inhibitor of PI3K was analyzed. Exposure of H2O2 (1mM H2O2 for 30min) to DLA cells caused ROS accumulation and resulted in increased phosphorylation of PI3K and downstream proteins PDK1 and AKT (Ser-473 and Thr-308), cell survival factors BAD and ERK1/2, as well as TNFR1. However, level of tumor suppressor PTEN was declined. Both PI-103 & quercetin suppressed the enhanced level of ROS and significantly down-regulated phosphorylation of AKT, PDK1, BAD and level of TNFR1 as well as increased the level of PTEN in H2O2 induced lymphoma cells. The overall result suggests that quercetin and PI3K inhibitor PI-103 attenuate PI3K-AKT pathway in a similar mechanism.

Mitochondria, cholesterol and cancer cell metabolism

Given the role of mitochondria in oxygen consumption, metabolism and cell death regulation, alterations in mitochondrial function or dysregulation of cell death pathways contribute to the genesis and progression of cancer. Cancer cells exhibit an array of metabolic transformations induced by mutations leading to gain-of-function of oncogenes and loss-of-function of tumor suppressor genes that include increased glucose consumption, reduced mitochondrial respiration, increased reactive oxygen species generation and cell death resistance, all of which ensure cancer progression. Cholesterol metabolism is disturbed in cancer cells and supports uncontrolled cell growth. In particular, the accumulation of cholesterol in mitochondria emerges as a molecular component that orchestrates some of these metabolic alterations in cancer cells by impairing mitochondrial function. As a consequence, mitochondrial cholesterol loading in cancer cells may contribute, in part, to the Warburg effect stimulating aerobic glycolysis to meet the energetic demand of proliferating cells, while protecting cancer cells against mitochondrial apoptosis due to changes in mitochondrial membrane dynamics. Further understanding the complexity in the metabolic alterations of cancer cells, mediated largely through alterations in mitochondrial function, may pave the way to identify more efficient strategies for cancer treatment involving the use of small molecules targeting mitochondria, cholesterol homeostasis/trafficking and specific metabolic pathways.

Oxidative Stress-Induced Protein Damage Inhibits DNA Repair and Determines Mutation Risk and Therapeutic Efficacy

The relationship between sun exposure and nonmelanoma skin cancer risk is well established. Solar UV (wavelength 280-400 nm) is firmly implicated in skin cancer development. Nucleotide excision repair (NER) protects against cancer by removing potentially mutagenic DNA lesions induced by UVB (280-320 nm). How the 20-fold more abundant UVA (320-400 nm) component of solar UV radiation increases skin cancer risk is not understood. Here it is demonstrated that the contribution of UVA to the effect of UV radiation on cultured human cells is largely independent of its ability to damage DNA. Instead, the effects of UVA reflect the induction of oxidative stress that causes extensive protein oxidation. Because NER proteins are among those damaged, UVA irradiation inhibits NER and increases the susceptibility of the cells to mutation by UVB. NER inhibition is a common consequence of oxidative stress. Exposure to chemical oxidants, treatment with drugs that deplete cellular antioxidants, and interventions that interfere with glucose metabolism to disrupt the supply of cellular reducing power all inhibit NER. Tumor cells are often in a condition of oxidative stress and one effect of the NER inhibition that results from stress-induced protein oxidation is an increased sensitivity to the anticancer drug cisplatin.

IMPLICATIONS

As NER is both a defense against cancer and a significant determinant of cell survival after treatment with anticancer drugs, its attenuation by protein damage under conditions of oxidative stress has implications for both cancer risk and for the effectiveness of anticancer therapy. Mol Cancer Res; 14(7); 612-22. ©2016 AACR.

ESeroS-GS Protects Neuronal Cells from Oxidative Stress by Stabilizing Lysosomes

γ-l-glutamyl-S-[2-[[[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-yl]oxy]carbonyl]-3-[[2-(1H-indol-3-yl)ethyl]amino]-3-oxopropyl]-l-cysteinylglycine sodium salt (ESeroS-GS) is a water-soluble derivative of α-tocopherol (vitamin E). We reported previously that ESeroS-GS can act as an anti-inflammatory agent and can induce cell death in breast cancer cells. However, the potential antioxidant capacities of ESeroS-GS remain elusive. Here, we measured its scavenging effects on free radicals and evaluated its protective effects on neuronal cells against oxidative stress. The results indicated that ESeroS-GS effectively scavenged both 2,2’-azinobis(3-ethylbenzothiazoline)-6-sulfonate free radicals (ABTS^•+) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals, and attenuated H₂O₂-induced neuronal cell death. H₂O₂ treatment induced lysosomal membrane permeabilization rapidly, and caused the redistribution of lysosomal proteases, which were responsible for the neuronal cell death. ESeroS-GS abolished the interaction between tBid and the lysosomal membranes, blocked the translocation of tBid to the lysosomal membranes, decreased its oligomerization within the membrane circumstances, prevented the lysosomal membrane permeabilization, and thus attenuated the neuronal cell death. These data suggest that ESeroS-GS protected the neuronal cells from oxidative stress by stabilizing lysosomal membranes, and thus might act as a novel neuroprotector for neuronal diseases associated with oxidative stress.

Fusarium tricinctum, An Endophytic Fungus Exhibits Cell Growth Inhibition and Antioxidant Activity

An endophytic fungus (strain T6) isolated from Taxus baccata was studied for its effect on the growth of human breast cancer cell line (MCF-7), human cervical cancer cell line (HeLa) and peripheral blood mononuclear cells (PBMCs) as well as for its antioxidant activity. Based on morphological characters and internal transcribed spacer (ITS) sequence analysis, this fungus (strain T6) was identified as Fusarium tricinctum. This fungus has shown inhibition in the growth of the MCF-7 and HeLa cancer cell lines. IC₅₀ values of the fungal extract were 225 ± 26 and 220 ± 18 μg ml^-1 for MCF-7 and HeLa cell lines, respectively. Further, F. tricinctum showed inhibition in the proliferation of concanavalin A stimulated PBMCs indicating its immunosuppressive potential (IC₅₀ value 110 ± 44 μg ml^-1). Tumour necrosis factor (TNF)-α production in concanavalin A stimulated PBMCs and MCF-7 were found to be inhibited which indicates that the antiproliferative effect may be associated with TNF-α. Free radical scavenging results revealed that this fungus also exhibited antioxidant activity (IC₅₀ value 482 ± 9 μg ml^-1). Present study results suggested that F. tricinctum has the potential to be used for therapeutic purposes because of its antiproliferative and antioxidant potential.

In vitro and in vivo antitumor effects of the Egyptian scorpion Androctonus amoreuxi venom in an Ehrlich ascites tumor model

Scorpion venom is a highly complex mixture of about 100-700 different components, where peptides are the major constituents with various biological and pharmacological properties including anticancer activities. In this study, anticancer efficacy of the venom of the Egyptian scorpion Androctonus amoreuxi has been evaluated. In vitro, the human breast cancer MCF-7 cell line was treated with the venom and the IC50 was estimated. In vivo studies, Ehrlich ascites carcinoma (EAC) cells were inoculated into CD-1 mice intraperitoneally to form liquid tumor or subcutaneously to form solid tumor and then treated with intraperitoneal injection with venom (0.22 mg/kg) every other day. The total tumor cells in the ascitic fluid and the size of the solid tumor were assessed after 14 and 30 days, respectively. In addition, the mean survival time (MST), body weight, tumor volume, PCV, viability of tumor cells, CBC, AST, ALP, creatinine, oxidative stress biomarkers (GSH, MDA, PCC), tumor marker Ki67, growth factor VEGF and caspase-3 were measured in normal control, EAC control and venom-treated groups (n = 6). Treatment with venom induced anti-tumor effects against liquid and in solid tumors as indicated by a significant (P < 0.05) reduction in tumor volume/size, count of viable EAC cells, expression of Ki67 and VEGF as well as by remarkable increases in MST and caspase-3 expression as compared to non-treated group. Interestingly, the venom restored the altered hematological and biochemical parameters of tumor-bearing animals and significantly increased their life span. These data indicate to (1) the cytotoxic potential effects of A. amoreuxi on tumor cells via anti-proliferative, apoptotic and anti-angiogenic activities; (2) opening a new avenue for further studies on the anti-cancer effects of this agent.

The mitochondrial phospholipid cardiolipin is involved in the regulation of T-cell proliferation

Challenge of the immune system with antigens induces a cascade of processes including activation of naïve T cells, induction of proliferation, differentiation into effector cells and finally contraction via apoptosis. To meet the dynamic requirements of an adequate immune response, T cells must metabolically adapt to actual situations by switching between catabolic and anabolic metabolism. In this context mitochondria are hubs of metabolic regulation. The phospholipid cardiolipin (CL) is crucial for the structural and functional integrity and, thus, the metabolism of mitochondria. The aim of this study was to verify a possible interrelationship between T cell proliferation and CL composition. For this purpose, we adjusted the proliferation of peripheral human T cells from volunteers by stimulation with different concentrations of the mitogen phytohaemagglutinin (PHA), inhibition with Cyclosporin A (CsA) and exposure of cells to different free fatty acids and subsequently analysed the composition of CL by LC/MS/MS spectroscopy. All of the treatments had significant effects on CL composition. Correlation analysis of the proliferation rate and CL composition revealed that only the amount of incorporated palmitoleic acid and the content of tetralinoleoyl-CL are significantly associated with the proliferation rate. This observation is strongly suggestive of a regulatory function of these particular CL components/species in the process of T cell proliferation. As CL is crucially involved in mitochondrial function one can speculate that changes in CL composition contribute to vital mitochondria-dependent adaptations of energy metabolism in T cells during immune response.

Apelin/APJ system: A novel therapeutic target for oxidative stress-related inflammatory diseases (Review)

Apelin, the endogenous ligand of APJ which is a member of G protein-coupled receptors, has been shown to be expressed in a variety of tissues in vivo and to exert significant biological effects. Studies have indicated that the apelin/APJ system is involved in the regulation of a variety of physiological functions and pathological processes, and that it is associated with cardiovascular diseases (such as atherosclerosis, hypertension, heart failure and myocardial injury), diabetes with microvascular complications, ischemia reperfusion injury, tumors, pre-eclampsia, as well as others. The occurrence of these diseases is closely related to endothelial dysfunction and the local inflammatory response; however, the occurrence of oxidative stress is related to vascular injury, due to the excessive generation of reactive oxygen species (ROS) and can lead to vascular damage and a series of inflammatory reactions. Therefore, this review summarizes the association between apelin/APJ, oxidative stress and inflammation-related diseases. In addition, drugs targeting the apelin/APJ system are recommended, thus providing a novel therapeutic strategy for oxidative stress-related inflammatory diseases.

PRIMA-1MET induces apoptosis through accumulation of intracellular reactive oxygen species irrespective of p53 status and chemo-sensitivity in epithelial ovarian cancer cells

There is an intensive need for the development of novel drugs for the treatment of epithelial ovarian cancer (EOC), the most lethal gynecologic malignancy due to the high recurrence rate. TP53 mutation is a common event in EOC, particularly in high-grade serous ovarian cancer, where it occurs in more than 90% of cases. Recently, PRIMA-1 and PRIMA‑1MET (p53 reactivation and induction of massive apoptosis and its methylated form) were shown to have an antitumor effect on several types of cancer. Despite that PRIMA-1MET is the first compound evaluated in clinical trials, the antitumor effects of PRIMA-1MET on EOC remain unclear. In this study, we investigated the therapeutic potential of PRIMA-1MET for the treatment of EOC cells. PRIMA-1MET treatment of EOC cell lines (n=13) resulted in rapid apoptosis at various concentrations (24 h IC50 2.6-20.1 µM). The apoptotic response was independent of the p53 status and chemo-sensitivity. PRIMA‑1MET treatment increased intracellular reactive oxygen species (ROS), and PRIMA-1MET-induced apoptosis was rescued by an ROS scavenger. Furthermore, RNA expression analysis revealed that the mechanism of action of PRIMA‑1MET may be due to inhibition of antioxidant enzymes, such as Prx3 and GPx-1. In conclusion, our results suggest that PRIMA-1MET represents a novel therapeutic strategy for the treatment of ovarian cancer irrespective of p53 status and chemo-sensitivity.

Photoactivated drug delivery and bioimaging

Among the various types of diseases, cancer remains one of the most leading causes of mortality that people are always suffering from and fighting with. So far, the effective cancer treatment demands accurate medical diagnosis, precise surgery, expensive medicine administration, which leads to a significant burden on patients, their families, and the whole national healthcare system around the world. In order to increase the therapeutic efficiency and minimize side effects in cancer treatment, various kinds of stimuli-responsive drug delivery systems and bioimaging platforms have been extensively developed within the past decades. Among them, the strategy of photoactivated approach has attracted considerable research interest because light enables the precise control, in a highly spatial and temporal manner, the release of drug molecules as well as the activation of bioimaging agents. In general, several appropriate photoresponsive systems, which are normally sensitive to ultraviolet (UV) or visible light irradiation to undergo the multiple reaction pathways such as photocleavage and photoisomerization strategy etc. have been mainly involved in the light activated cancer therapies. Considering the potential issues of poor tissue penetration and high photoctotoxicity of short wavelength light, the recently emerged therapies based on long-wavelength irradiation, e.g., near-infrared (NIR) light (700-1000 nm), have displayed distinct advantages in biomedical applications. The light irradiation at NIR window indicates minimized photodamage, deep penetration, and low autofluorescence in living cells and tissues, which are of clinical importance in the desired diagnosis and therapy. In this review article, we introduce the recent advances in light-activated drug release and biological imaging mainly for anticancer treatment. Various types of strategies such as photocage, photo-induced isomerization, optical upconversion, and photothermal release by which different wavelength ranges of light can play the important roles in the controlled therapeutic or imaging agents delivery, and activation will be systemically discussed. In addition, the challenges and future perspectives for photo-based cancer theranostics will be also summarized. WIREs Nanomed Nanobiotechnol 2017, 9:e1408. doi: 10.1002/wnan.1408 For further resources related to this article, please visit the WIREs website.

The combination of three molecular markers can be a valuable predictive tool for the prognosis of hepatocellular carcinoma patients

Based on molecular profiling, several prognostic markers for HCC are also used in clinic, but only a few genes have been identified as useful. We collected 72 post-operative liver cancer tissue samples. Genes expression were tested by RT-PCR. Multilayer perceptron and discriminant analysis were built, and their ability to predict the prognosis of HCC patients were tested. Receiver operating characteristic (ROC) analysis was performed and multivariate analysis with Cox’s Proportional Hazard Model was used for confirming the markers’predictive efficiency for HCC patients’survival. A simple risk scoring system devised for further predicting the prognosis of liver tumor patients. Multilayer perceptron and discriminant analysis showed a very strong predictive value in evaluating liver cancer patients’prognosis. Cox multivariate regression analysis demonstrated that DUOX1, GLS2, FBP1 and age were independent risk factors for the prognosis of HCC patients after surgery. Finally, the risk scoring system revealed that patients whose total score >1 and >3 are more likely to relapse and die than patients whose total score ≤1 and ≤3. The three genes model proposed proved to be highly predictive of the HCC patients’ prognosis. Implementation of risk scoring system in clinical practice can help in evaluating survival of HCC patients after operation.

Dual oxidase 1: A predictive tool for the prognosis of hepatocellular carcinoma patients

Dual oxidase 1 (DUOX1), which is the main source of reactive oxygen species (ROS) production in the airway, can be silenced in human lung cancer and hepatocellular carcinomas. However, the prognostic value of DUOX1 expression in hepatocellular carcinoma patients is still unclear. We investigated the prognostic value of DUOX1 expression in liver cancer patients. DUOX1 mRNA expression was determined in tumor tissues and non-tumor tissues by real-time PCR. For evaluation of the prognostic value of DUOX1 expression, Kaplan-Meier method and Cox's proportional hazards model (univariate analysis and multivariate analysis) were employed. A simple risk score was devised by using significant variables obtained from the Cox's regression analysis to further predict the HCC patient prognosis. We observed a reduced DUOX1 mRNA level in the cancer tissues in comparison to the non-cancer tissues. More importantly, Kaplan-Meier analysis showed that patients with high DUOX1 expression had longer disease-free survival and overall survival compared with those with low expression of DUOX1. Cox's regression analysis indicated that DUOX1 expression, age, and intrahepatic metastasis may be significant prognostic factors for disease-free survival and overall survival. Finally, we found that patients with total scores of >2 and >1 were more likely to relapse and succumb to the disease than patients whose total scores were ≤2 and ≤1. In conclusion, DUOX1 expression in liver tumors is a potential prognostic tool for patients. The risk scoring system is useful for predicting the survival of liver cancer patients after tumor resection.

Phyto-mediated nanostructured carriers based on dual vegetable actives involved in the prevention of cellular damage

The growing scientific interest in exploitation of vegetable bioactives has raised a number of questions regarding their imminent presence in pharmaceutical formulations. This study intends to demonstrate that a dual combination between vegetable oil (e.g. thistle oil, safflower oil, sea buckthorn oil) and a carrot extract represents an optimal approach to formulate safe carrier systems that manifest cell regeneration effect and promising antioxidant and anti-inflammatory activity. Inclusion of both natural actives into lipid carriers imparted a strong negative charge on the nanocarrier surface (up to -45mV) and displayed average sizes of 70nm to 140nm. The entrapment efficiency of carrot extract into nanostructured carriers ranged between 78.3 and 88.3%. The in vitro release study has demonstrated that the entrapment of the extract represents a viable way for an equilibrated release of carotenoids. Besides the excellent antioxidant properties (e.g. scavenging up to 98% of the free oxygen radicals), the results of cellular integrity (e.g. cell viability of 133%) recommend these nanocarriers based on dual carrot extract-bioactive oil as a promising trend for the treatment of certain disorders in which oxidative stress plays a prominent role. In addition, the lipid nanocarriers based on safflower oil and sea buckthorn oil demonstrated an anti-inflammatory effect on LPS induced THP-1 macrophages, by inhibiting the secretion of two pro-inflammatory cytokines, IL-6 and TNF-α.

Oxidative stress and proteasome inhibitors in multiple myeloma

Multiple myeloma is a form of plasma cell neoplasm that accounts for approximately 10% of all hematological malignancies. Recently, several novel drugs have been discovered that almost doubled the overall survival of multiple myeloma patients. One of these drugs, the first-in-class proteasome inhibitor bortezomib (Velcade) has demonstrated remarkable response rates in multiple myeloma patients, and yet, currently this disease remains incurable. The major factor undermining the success of multiple myeloma treatment is a rapidly emerging resistance to the available therapy. Thus, the development of stand-alone or adjuvant anti-myeloma agents becomes of paramount importance. Overproduction of intracellular reactive oxygen species (ROS) often accompanies malignant transformation due to oncogene activation and/or enhanced metabolism in tumor cells. As a result, these cells possess higher levels of ROS and lower levels of antioxidant molecules compared to their normal counterparts. Unbalanced production of ROS leads to oxidative stress which, if left unchecked, could be toxic for the cell. In multiple myeloma cells where high rates of immunoglobulin synthesis is an additional factor contributing to overproduction of ROS, further induction of oxidative stress can be an effective strategy to cope with this disease. Here we will review the available data on the role of oxidative stress in the cytotoxicity of proteasome inhibitors and the use of ROS-inducing compounds as anti-myeloma agents.

Anticancer therapeutic potential of Mn porphyrin/ascorbate system

Ascorbate (Asc) as a single agent suppressed growth of several tumor cell lines in a mouse model. It has been tested in a Phase I Clinical Trial on pancreatic cancer patients where it exhibited no toxicity to normal tissue yet was of only marginal efficacy. The mechanism of its anticancer effect was attributed to the production of tumoricidal hydrogen peroxide (H2O2) during ascorbate oxidation catalyzed by endogenous metalloproteins. The amount of H2O2 could be maximized with exogenous catalyst that has optimized properties for such function and is localized within tumor. Herein we studied 14 Mn porphyrins (MnPs) which differ vastly with regards to their redox properties, charge, size/bulkiness and lipophilicity. Such properties affect the in vitro and in vivo ability of MnPs (i) to catalyze ascorbate oxidation resulting in the production of H2O2; (ii) to subsequently employ H2O2 in the catalysis of signaling proteins oxidations affecting cellular survival pathways; and (iii) to accumulate at site(s) of interest. The metal-centered reduction potential of MnPs studied, E1/2 of Mn(III)P/Mn(II)P redox couple, ranged from -200 to +350 mV vs NHE. Anionic and cationic, hydrophilic and lipophilic as well as short- and long-chained and bulky compounds were explored. Their ability to catalyze ascorbate oxidation, and in turn cytotoxic H2O2 production, was explored via spectrophotometric and electrochemical means. Bell-shape structure-activity relationship (SAR) was found between the initial rate for the catalysis of ascorbate oxidation, vo(Asc)ox and E1/2, identifying cationic Mn(III) N-substituted pyridylporphyrins with E1/2>0 mV vs NHE as efficient catalysts for ascorbate oxidation. The anticancer potential of MnPs/Asc system was subsequently tested in cellular (human MCF-7, MDA-MB-231 and mouse 4T1) and animal models of breast cancer. At the concentrations where ascorbate (1mM) and MnPs (1 or 5 µM) alone did not trigger any alteration in cell viability, combined treatment suppressed cell viability up to 95%. No toxicity was observed with normal human breast epithelial HBL-100 cells. Bell-shape relationship, essentially identical to vo(Asc)oxvs E1/2, was also demonstrated between MnP/Asc-controlled cytotoxicity and E1/2-controlled vo(Asc)ox. Magnetic resonance imaging studies were conducted to explore the impact of ascorbate on T1-relaxivity. The impact of MnP/Asc on intracellular thiols and on GSH/GSSG and Cys/CySS ratios in 4T1 cells was assessed and cellular reduction potentials were calculated. The data indicate a significant increase in cellular oxidative stress induced by MnP/Asc. Based on vo(Asc)oxvs E1/2 relationships and cellular toxicity, MnTE-2-PyP(5+) was identified as the best catalyst among MnPs studied. Asc and MnTE-2-PyP(5+) were thus tested in a 4T1 mammary mouse flank tumor model. The combination of ascorbate (4 g/kg) and MnTE-2-PyP(5+) (0.2mg/kg) showed significant suppression of tumor growth relative to either MnTE-2-PyP(5+) or ascorbate alone. About 7-fold higher accumulation of MnTE-2-PyP(5+) in tumor vs normal tissue was found to contribute largely to the anticancer effect.

Antioxidants of Edible Mushrooms

Oxidative stress caused by an imbalanced metabolism and an excess of reactive oxygen species (ROS) lead to a range of health disorders in humans. Our endogenous antioxidant defense mechanisms and our dietary intake of antioxidants potentially regulate our oxidative homeostasis. Numerous synthetic antioxidants can effectively improve defense mechanisms, but because of their adverse toxic effects under certain conditions, preference is given to natural compounds. Consequently, the requirements for natural, alternative sources of antioxidant foods identified in edible mushrooms, as well as the mechanistic action involved in their antioxidant properties, have increased rapidly. Chemical composition and antioxidant potential of mushrooms have been intensively studied. Edible mushrooms might be used directly in enhancement of antioxidant defenses through dietary supplementation to reduce the level of oxidative stress. Wild or cultivated, they have been related to significant antioxidant properties due to their bioactive compounds, such as polyphenols, polysaccharides, vitamins, carotenoids and minerals. Antioxidant and health benefits, observed in edible mushrooms, seem an additional reason for their traditional use as a popular delicacy food. This review discusses the consumption of edible mushrooms as a powerful instrument in maintaining health, longevity and life quality.

Oxidative/antioxidative enzyme-mediated antiproliferative and proapoptotic effects of the GPER1 agonist G-1 on lung cancer cells

Estrogen mediates fast signal responses or transcriptional events via G protein-coupled estrogen receptor 1 (GPER1). However, there is no data on the effect of GPER1 on lung cancer cell proliferation and apoptosis. The present study aimed to analyze the anticancer effects of the GPER1 agonist G-1 on A549 human lung cancer cells. A549 cells were treated with 17β-estradiol and G-1, and cell proliferation was analyzed using MTT and WST assays. In addition, the apoptotic effects induced by G-1 were investigated using acridine orange/ethidium bromide staining. A549 cells were treated with a half maximal inhibitory concentration of G-1 for 72 h, and nitric oxide (NO) levels and superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) enzyme activities were analyzed by spectrophotometry. The results revealed that G-1 significantly decreased cell proliferation. In addition to the antiproliferative effect of G-1, a marked increase in apoptotic activity was observed when cells were treated with 2×10^-5 M G-1. Furthermore, G-1 increased NO levels, and SOD and GPx activity. These findings indicate that the GPER1 agonist G-1 is able to exert antiproliferative and proapoptotic effects on A549 cells, and that oxidant and antioxidant molecules may mediate these effects.