Glutathione and modulation of cell apoptosis

Mcl-1 Inhibitor Induces Cells Death in BRAF-Mutant Amelanotic Melanoma Trough GSH Depletion, DNA Damage and Cell Cycle Changes

Mcl-1 is a potent antiapoptotic protein and amplifies frequently in many human cancer. Currently, it is considered that the extensively expressed of Mcl-1 protein in melanoma cells is associated with rapid tumor progression, poor prognosis and low chemosensitivity. Therefore, the antiapoptotic protein Mcl-1 could be considered as a potential target for malignant melanoma treatment. The aim of this study was to assess the effect of MIM1 a specific low molecular Mcl-1 protein inhibitor and mixture of MIM1 and dacarbazine on the viability, cell cycle progression and apoptosis induction in amelanotic C32 melanoma cells. The cytotoxic activity of MIM1 towards C32 melanoma cells was examined by the WST-1 test. The Mcl-1 protein level as a drug target in amelanotic melanoma cells was defined by Western blot analysis. Cell cycle progression, DNA fragmentation as well as GSH depletion were determined by fluorescence image cytometer NucleoCounter NC-3000. The obtained results demonstrate that the specific Mcl-1 protein inhibitor - MIM1 decreases cell viability and induce apoptosis (S-phase arrest, DNA fragmentation and redox imbalance) in amelanotic melanoma cells and intensify the proapoptotic properties of DTIC, as a result of interactions with Mcl-1 protein. Taken together, the presented data suggest that Mcl-1 protein is a an important target in malignant melanoma treatment and provide for the first time convincing evidence that MIM1, which inhibits Mcl-1 antiapoptotic protein is able to induce apoptosis and sensitize melanoma cells to alkylating agent.

Glutathione Transferase P1-1 an Enzyme Useful in Biomedicine and as Biomarker in Clinical Practice and in Environmental Pollution

Glutathione transferase P1-1 (GSTP1-1) is expressed in some human tissues and is abundant in mammalian erythrocytes (here termed e-GST). This enzyme is able to detoxify the cell from endogenous and exogenous toxic compounds by using glutathione (GSH) or by acting as a ligandin. This review collects studies that propose GSTP1-1 as a useful biomarker in different fields of application. The most relevant studies are focused on GSTP1-1 as a biosensor to detect blood toxicity in patients affected by kidney diseases. In fact, this detoxifying enzyme is over-expressed in erythrocytes when unusual amounts of toxins are present in the body. Here we review articles concerning the level of GST in chronic kidney disease patients, in maintenance hemodialysis patients and to assess dialysis adequacy. GST is also over-expressed in autoimmune disease like scleroderma, and in kidney transplant patients and it may be used to check the efficiency of transplanted kidneys. The involvement of GSTP in the oxidative stress and in other human pathologies like cancer, liver and neurodegenerative diseases, and psychiatric disorders is also reported. Promising applications of e-GST discussed in the present review are its use for monitoring human subjects living in polluted areas and mammals for veterinary purpose.

Putative Role of Nuclear Factor-Kappa B But Not Hypoxia-Inducible Factor-1α in Hypoxia-Dependent Regulation of Oxidative Stress in Hematopoietic Stem and Progenitor Cells

Aims: Adaptation to low oxygen of hematopoietic stem cells (HSCs) in the bone marrow has been demonstrated to depend on the activation of hypoxia-inducible factor (HIF)-1α as well as the limited production of reactive oxygen species (ROS). In this study, we aimed at determining whether HIF-1α is involved in protecting HSCs from ROS. Results: Oxidative stress was induced by DL-buthionine-(S,R)-sulfoximine (BSO)-treatment, which increases the mitochondrial ROS level. Hypoxia rescued Lineage-Sca-1+c-kit+ (LSK) cells from BSO-induced apoptosis, whereas cells succumbed to apoptosis in normoxia. Apoptosis in normoxia was inhibited with the antioxidant N-acetyl-L-cysteine or by overexpression of anti-apoptotic BCL-2. Moreover, stabilized expression of oxygen-insensitive HIFs could not protect LSK cells from oxidative stress-induced apoptosis at normoxia, neither could short hairpin RNA to Hif-1α inhibit the protective effects by hypoxia in LSK cells. Likewise, BSO treatment of LSK cells from Hif-1α knockout mice did not suppress the effects seen in hypoxia. Microarray analysis identified the nuclear factor-kappa B (NF-κB) pathway as a pathway induced by hypoxia. By using NF-κB lentiviral construct and DNA-binding assay, we found increased NF-κB activity in cells cultured in hypoxia compared with normoxia. Using an inhibitor against NF-κB activation, we could confirm the involvement of NF-κB signaling as BSO-mediated cell death was significantly increased in hypoxia after adding the inhibitor. Innovation: HIF-1α is not involved in protecting HSCs and progenitors to elevated levels of ROS on glutathione depletion during hypoxic conditions. Conclusion: The study proposes a putative role of NF-κB signaling as a hypoxia-induced regulator in early hematopoietic cells.

The antioxidant system in the soleus muscle of growing rats is stimulated by the administration of a low-protein/high-carbohydrate diet

The aim of this study was to evaluate the generation of reactive oxygen species (ROS) by xanthine oxidase (XO), the enzymatic antioxidant system and oxidative damage in soleus and extensor digitorum longus (EDL) muscles of growing rats fed a low-protein, high-carbohydrate (LPHC; 6% protein, 74% carbohydrate) diet for 15 days. The LPHC diet increased the total antioxidant capacity by 45% and the activities of glutathione peroxidase (GPx), glutathione reductase and catalase in the soleus muscles. There was an increase in the carbonylated proteins with no increase thiobarbituric acid reactive substances (TBARS), although the XO activity had increased 20%. In EDL muscles, the LPHC diet increased XO activity by 66% and the TBARS levels by 80%, and only GPx had its activity increased. These results suggest that the enzymatic antioxidant system of the soleus muscle has a better response to the increase of ROS production stimulated by LPHC diet.

Possible Association of Smokeless Tobacco Dependent Impairment in the Erythrocytes and Platelets Membranes of Human Male Volunteers: An Observation

Background:

Smokeless tobacco (SLT) acts as a modifier of erythrocyte and platelet membranes by disrupting antioxidant system with the concomitant increase in free radical production and induction of apoptosis.

Methods:

The SLT users was that individuals used gutkha and khaini products (Khaleja/mahak chaini brand respectively) habitually, at least >20 times per week consists of 50-60 g during the last 2-4 years.

Results:

The gutkha and khaini users found to be significantly increased levels of iNOS (Inducible nitric oxide synthase) enzyme in plasma, erythrocytes, and platelet membranes when compared to normal controls. The gutkha and khaini users exhibited that the significant increase in the levels of gene expression of apoptotic proteins (Bcl₂-B cell lymphoma gene 2, Bax, caspases 8, caspase 10, and caspase 12), IL-6 (Interleukin-6), and decreased levels of TNF-α (Tumor necrosis factor-alpha) and decreased expression of caspase 12 of khaini users were observed from blood samples. The significant increase in the concentrations of peroxynitrites (ONOO-), nitric oxide (NO) (Nitrates and nitrites), malondialdehyde (MDA), cholesterol, and phospholipids were reported in the smokeless tobacco users of erythrocytes and platelets. The experimental subjects showed that the increased osmotic fragility and decreased membrane fluidity of erythrocytes and platelets in comparison with non-tobacco users. The normal subjects had been exposed that the proper functioning of antioxidant enzymes and decreased enzyme activities of antioxidants were reported by SLT users.

Conclusion:

The smokeless tobacco products are exerted chronic damage to membranes of erythrocytes and platelets and elevation of apoptosis in the prolonged periods of human male volunteers.

Targeting of oxidative stress and inflammation through ROS/NF-kappaB pathway in phosphine-induced hepatotoxicity mitigation

AIMS

Poisoning with aluminium phosphide (AlP) commonly has a high rate of mortality and morbidities. Phosphine gas is the main cause of AlP poisoning that has deleterious effect on multi-organs especially heart, kidney, and liver. Furthermore, several studies reported that resveratrol has cytoprotective effects through its pleiotropic property. The purpose of this study was to estimate the dose-dependent role of resveratrol on phosphine induced acute hepatic toxicity in rat model.

MAIN METHODS

The rats have been exposed to LD₅₀ of AlP (12 mg/kg) by gavage, and resveratrol doses (20, 40, and 80 mg/kg) were injected 30 min after intoxication. After 24 h, the serum and liver tissue were collected for present study.

KEY FINDINGS

The results indicated that phosphine causes an alteration in oxidative stress markers including elevation of ROS, and GSH level, MPO activity, reduction in SOD, catalase and G6PD activity as well as reduction in SOD1 and catalase expression. Furthermore, phosphine significantly induced phosphorylation of IkappaB, NF-kappaB and up-regulation of TNF-α, IL-1β, IL-6, and ICAM-1 expression. Also, phosphine induces markedly reduced hepatocytes lives cell and elevated apoptosis and necrosis. Co-treatment of resveratrol in a dose-dependent manner reversed aforementioned alterations. All in all, histological analysis indicated a deleterious effect of phosphine on the liver, which is mitigated by resveratrol administration.

SIGNIFICANCE

The results of the present study suggest targeting ROS/NF-kappaB signalling pathway by resveratrol may have a significant effect on the improvement of hepatic injury induced by phosphine. It also may be a possible candidate for the treatment of phosphine-poisoning.

Lipidomics reveals insights on the biological effects of copper oxide nanoparticles in a human colon carcinoma cell line

Engineered nanomaterials have unique properties compared to their bulk counterparts. Copper oxide nanoparticles (CuO NPs) are one example of nanomaterials used in a wide range of consumer products due to their conductivity and biocidal properties. While CuO NPs can induce toxicity in various organisms, their interactions with different organisms and how they affect cellular homeostasis is yet to be fully understood. In this work, the toxicity of CuO NPs was evaluated in different human cell lines (colorectal carcinoma, cervical cancer, embryonic kidney, and lung fibroblast), showing a dose-dependent toxicity. An untargeted lipidomics approach using liquid chromatography-quadrupole time of flight mass spectrometry was employed in a human colon carcinoma cell line to investigate the impact of CuO NP exposure at the cellular level. A 24 h CuO NP exposure at 2.5 and 5 μg mL-1 resulted in upregulation of different metabolites: triacylglycerols, phosphatidylcholines, and ceramides accumulated. The most profound increase in a dose-dependent manner was observed in ceramides, specifically in C18:0, C18:1, and C22:0 species, with up to ∼10 fold accumulations. Further experiments suggested that activation of autophagy and oxidative stress could be responsible for the toxicity observed in these cell lines. Increases in the level of glutathione oxide (∼7 fold) also supported the activation of oxidative stress upon CuO NP treatment. Based on the changes in different metabolites induced by CuO NP exposure and previous studies from our laboratory, we propose that autophagy and oxidative stress could play a role in CuO NP-induced toxicity.

Glutathione reductase (GSR) gene deletion and chromosome 8 aneuploidy in primary lung cancers detected by fluorescence in situ hybridization

Our recent study demonstrated that cancer cells with compromised glutathione homeostasis, including reduced expression of the glutathione reductase (GSR) gene, were selectively killed by inhibition of thioredoxin reductase. The human GSR gene is located on chromosome 8p, a region often lost in lung and other cancers. However, whether GSR is altered in primary lung cancer remains unknown. To analyze alterations of GSR in lung cancer, we performed fluorescence in situ hybridization with probes for GSR and the chromosome 8 centromere (CEP8) in 45 surgical specimens of primary lung cancer, including 24 lung adenocarcinomas, 10 squamous cell carcinomas, 8 neuroendocrine cancers, and 3 small cell lung cancers. Twenty-five surgically resected normal lung tissue specimens from these lung cancer patients were used as a controls. The signal ratio of GSR to CEP8 per cell was used to identify gain or loss of GSR. GSR loss was detected in 6 of 24 (25%) adenocarcinoma specimens and 5 of 10 (50%) squamous cell carcinoma specimens, but not in neuroendocrine cancer or small cell lung cancer specimens. We also found that 19 of 45 (42%) specimens had chromosome 8 aneuploidy (more or less than 2 signals for CEP8), including 8 with both aneuploidy and GSR deletion. Chromosome 8 aneuploidy was detected in all types of lung cancer analyzed. Univariate and multivariable logistic regression analyses indicated that male patients had an increased risk of GSR deletion (hazard ratio [HR] = 4.77, 95% confidence interval [CI] = 1.00-22.86, P = 0.051), and patients who had undergone preoperative radiation therapy or had a self-reported history of cigarette smoking had an increased risk of chromosome 8 aneuploidy (preoperative radiation: HR = 18.63, 95% CI = 0.90-384.17, P = 0.058; smoking: HR = 7.59, 95% CI = 0.86-66.75, P = 0.068), although the p values did not reach significance. Because GSR deficiency and chromosome 8 aneuploidy have implications in targeted therapy and/or immunotherapy for cancer, they might serve as predictive biomarkers for precision therapy of lung cancers.

The Evaluation of Glutathione Reductase and Malondialdehyde Levels in Patients With Lumbar Disc Degeneration Disease

BACKGROUND/AIM

Increased oxidative stress plays a crucial role in pathogenesis of various diseases. The present study aims to investigate glutathione reductase (GR) and malondialdehyde (MDA) enzymes as markers of oxidative stress mechanisms in lumbar disc degeneration disease (LDDD).

PATIENTS AND METHODS

The study group consisted of 39 patients diagnosed with LDD and 37 healthy individuals in the control group. The enzyme-linked immunosorbent assay (ELISA) method was used to determine serum GR and MDA levels in the two study groups.

RESULTS

Serum GR levels were significantly lower (p=0.008), while MDA levels were significantly higher in the patient group compared to the controls (p=0.025).

CONCLUSION

Oxidative stress mechanisms play a crucial role in disc degeneration and GR deficiency could be an eligible risk factor for LDDD.

Delta-Tocotrienol Modulates Glutamine Dependence by Inhibiting ASCT2 and LAT1 Transporters in Non-Small Cell Lung Cancer (NSCLC) Cells: A Metabolomic Approach

The growth and development of non-small cell lung cancer (NSCLC) primarily depends on glutamine. Both glutamine and essential amino acids (EAAs) have been reported to upregulate mTOR in NSCLC, which is a bioenergetics sensor involved in the regulation of cell growth, cell survival, and protein synthesis. Seen as novel concepts in cancer development, ASCT2 and LAT transporters allow glutamine and EAAs to enter proliferating tumors as well as send a regulatory signal to mTOR. Blocking or downregulating these glutamine transporters in order to inhibit glutamine uptake would be an excellent therapeutic target for treatment of NSCLC. This study aimed to validate the metabolic dysregulation of glutamine and its derivatives in NSCLC using cellular 1H-NMR metabolomic approach while exploring the mechanism of delta-tocotrienol (δT) on glutamine transporters, and mTOR pathway. Cellular metabolomics analysis showed significant inhibition in the uptake of glutamine, its derivatives glutamate and glutathione, and some EAAs in both cell lines with δT treatment. Inhibition of glutamine transporters (ASCT2 and LAT1) and mTOR pathway proteins (P-mTOR and p-4EBP1) was evident in Western blot analysis in a dose-dependent manner. Our findings suggest that δT inhibits glutamine transporters, thus inhibiting glutamine uptake into proliferating cells, which results in the inhibition of cell proliferation and induction of apoptosis via downregulation of the mTOR pathway.

Hematoxylin assay of cupric chelation can give false positive results

Some compounds without apparent chelation sites have been shown to chelate cupric ions using the hematoxylin assay. Since these compounds also have reduction potential (direct antioxidant effect), the aim of this study was to determine the possible interference of reducing agents with the hematoxylin assay. Four different known reducing agents (hydroxylamine, vitamin C, trolox - a water-soluble form of vitamin E and reduced glutathione /GSH/) were selected for the study together with oxidized glutathione (GSSG) for comparison. All tested compounds behaved as cupric chelators in the spectrophotometric mildly competitive hematoxylin assay. In-depth analysis however showed that only GSH and GSSG were able to form complexes with both cupric and cuprous ions and only GSSG partly retained copper in its complexes in the more competitive bathocuproine assay. Further experiments showed that with the exception of GSSG, all other compounds reduce Cu²⁺ ions. Conclusion: Compounds reducing copper such as antioxidants can give false positive results in the hematoxylin-screening assay. GSSG is a stronger Cu chelator than GSH and does not reduce Cu, in contrast to the latter and thus may be a protective element after oxidation of GSH.

Glutathione accelerates osteoclast differentiation and inflammatory bone destruction

Chronic inflammation associated with bone tissues often destructs bones, which is essentially performed by osteoclasts in the presence of immunoregulatory molecules. Hence, regulating osteoclastogenesis is crucial to develop therapeutics for bone-destructive inflammatory diseases. It is believed that reactive oxygen species (ROS) are involved in receptor activator of NF-κB (RANK) ligand (RANKL)-induced osteoclast differentiation, and, therefore, glutathione (GSH), the most abundant endogenous antioxidant, suppresses osteoclast differentiation and bone resorption by RANKL. Interestingly, GSH also contributes to inflammatory responses, and the effects of GSH on osteoclast differentiation and bone destruction under inflammatory conditions have not yet been determined. Here, we investigated how GSH affects inflammatory cytokine-stimulated osteoclast differentiation in vitro and in a mouse model of inflammatory bone destruction. We found that GSH significantly promoted TNFα-stimulated osteoclast formation, while an inhibitor of GSH synthesis, buthionine sulfoximine, suppressed it. GSH facilitated the nuclear localisation of the nuclear factor of activated T cells c1 (NFATc1) protein, a master regulator of osteoclastogenesis, as well as the expression of osteoclast marker genes in a dose-dependent manner. N-acetylcysteine, a substrate of GSH synthesis, also stimulated osteoclast formation and NFATc1 nuclear localisation. GSH did not suppress cell death after osteoclast differentiation. In mouse calvaria injected with lipopolysaccharide, GSH treatment resulted in a fivefold increase in the osteolytic lesion area. These results indicate that GSH accelerates osteoclast differentiation and inflammatory bone destruction, suggesting GSH appears to be an important molecule in the mechanisms responsible for inflammatory bone destruction by osteoclasts.

Apurinic/apyrimidinic endonuclease/redox factor 1 (APE1) alleviates myocardial hypoxia-reoxygenation injury by inhibiting oxidative stress and ameliorating mitochondrial dysfunction

Oxidative stress and mitochondrial dysfunction are considered to be activators of apoptosis and serve a pivotal role in the pathogenesis of myocardial ischemia-reperfusion (MI/R) injury. Apurinic/apyrimidinic endonuclease/redox factor 1 (APE1) is a multifunctional protein that processes the cellular response to DNA damage and oxidative stress. Little is known about the role of APE1 in the pathogenesis of MI/R injury. The aim of the present study was to investigate the effects of APE1 on hypoxia-reoxygenation (H/R)-induced H9c2 cardiomyocyte injury and the underlying mechanism responsible. It was demonstrated that H/R decreased cell viability and increased lactic dehydrogenase (LDH) release, as well as reducing APE1 expression in H9c2 cells. However, APE1 overexpression induced by transfection with APE1-expressing lentivirus significantly increased H9c2 cell viability, decreased LDH release, decreased apoptosis and reduced caspase-3 activity in H/R-treated H9c2 cells. APE1 overexpression ameliorated the H/R-induced increases in reactive oxygen species and NAPDH oxidase expression, as well as the decreases in superoxide dismutase activity and glutathione expression. Furthermore, APE1 overexpression increased mitochondrial membrane potential and ATP production, stabilized electron transport chain activity (as illustrated by increased NADH-ubiquinone oxidoreductase, succinate dehydrogenase, coenzyme Q-cytochrome c oxidoreductase and cytochrome c oxidase activities) and decreased the ratio of B-cell lymphoma 2-associated X protein/B-cell lymphoma 2 in H/R, improving mitochondrial dysfunction. In conclusion, the results of the present study suggest that APE1 alleviates H/R-induced injury in H9c2 cells by attenuating oxidative stress and ameliorating mitochondrial dysfunction. APE1 may therefore be used as an effective treatment for MI/R injury.

Kinetics of Glutathione Depletion and Antioxidant Gene Expression as Indicators of Chemical Modes of Action Assessed in Vitro in Mouse Hepatocytes with Enhanced Glutathione Synthesis

Here we report a vertically integrated in vitro - in silico study that aims to elucidate the molecular initiating events involved in the induction of oxidative stress (OS) by seven diverse chemicals (cumene hydroperoxide, t-butyl hydroperoxide, hydroquinone, t-butyl hydroquinone, bisphenol A, Dinoseb, and perfluorooctanoic acid). To that end, we probe the relationship between chemical properties, cell viability, glutathione (GSH) depletion, and antioxidant gene expression. Concentration-dependent effects on cell viability were assessed by MTT assay in two Hepa-1 derived mouse liver cell lines: a control plasmid vector transfected cell line (Hepa-V), and a cell line with increased glutamate-cysteine ligase (GCL) activity and GSH content (CR17). Changes to intracellular GSH content and mRNA expression levels for the Nrf2-driven antioxidant genes Gclc, Gclm, heme oxygenase-1 ( Hmox1), and NADPH quinone oxidoreductase-1 ( Nqo1) were monitored after sublethal exposure to the chemicals. In silico models of covalent and redox reactivity were used to rationalize differences in activity of quinones and peroxides. Our findings show CR17 cells were generally more resistant to chemical toxicity and showed markedly attenuated induction of OS biomarkers; however, differences in viability effects between the two cell lines were not the same for all chemicals. The results highlight the vital role of GSH in protecting against oxidative stress-inducing chemicals as well as the importance of probing molecular initiating events in order to identify chemicals with lower potential to cause oxidative stress.

Glutathione depleting drugs, antioxidants and intestinal calcium absorption

Glutathione (GSH) is a tripeptide that constitutes one of the main intracellular reducing compounds. The normal content of GSH in the intestine is essential to optimize the intestinal Ca²⁺ absorption. The use of GSH depleting drugs such as DL-buthionine-S,R-sulfoximine, menadione or vitamin K₃, sodium deoxycholate or diets enriched in fructose, which induce several features of the metabolic syndrome, produce inhibition of the intestinal Ca²⁺ absorption. The GSH depleting drugs switch the redox state towards an oxidant condition provoking oxidative/nitrosative stress and inflammation, which lead to apoptosis and/or autophagy of the enterocytes. Either the transcellular Ca²⁺ transport or the paracellular Ca²⁺ route are altered by GSH depleting drugs. The gene and/or protein expression of transporters involved in the transcellular Ca²⁺ pathway are decreased. The flavonoids quercetin and naringin highly abrogate the inhibition of intestinal Ca²⁺ absorption, not only by restoration of the GSH levels in the intestine but also by their anti-apoptotic properties. Ursodeoxycholic acid, melatonin and glutamine also block the inhibition of Ca²⁺ transport caused by GSH depleting drugs. The use of any of these antioxidants to ameliorate the intestinal Ca²⁺ absorption under oxidant conditions associated with different pathologies in humans requires more investigation with regards to the safety, pharmacokinetics and pharmacodynamics of them.

Imidazo[1,2-b]pyrazole-7-carboxamides Induce Apoptosis in Human Leukemia Cells at Nanomolar Concentrations

Leukemia, the malignancy of the hematopoietic system accounts for 10% of cancer cases with poor overall survival rate in adults; therefore, there is a high unmet medical need for the development of novel therapeutics. Eight imidazo[1,2-b]pyrazole-7-carboxamides have been tested for cytotoxic activity against five leukemia cell lines: Acute promyelocytic leukemia (HL-60), acute monocytic leukemia (THP-1), acute T-lymphoblastic leukemia (MOLT-4), biphenotypic B myelomonocytic leukemia (MV-4-11), and erythroleukemia (K-562) cells in vitro. Imidazo[1,2-b]pyrazole-7-carboxamides hampered the viability of all five leukemia cell lines with different potential. Optimization through structure activity relationship resulted in the following IC50 values for the most effective lead compound DU385: 16.54 nM, 27.24 nM, and 32.25 nM on HL-60, MOLT-4, MV-4-11 cells, respectively. Human primary fibroblasts were much less sensitive in the applied concentration range. Both monolayer or spheroid cultures of murine 4T1 and human MCF7 breast cancer cells were less sensitive to treatment with 1.5⁻10.8 μM IC50 values. Flow cytometry confirmed the absence of necrosis and revealed 60% late apoptotic population for MV-4-11, and 50% early apoptotic population for HL-60. MOLT-4 cells showed only about 30% of total apoptotic population. Toxicogenomic study of DU385 on the most sensitive MV-4-11 cells revealed altered expression of sixteen genes as early (6 h), midterm (12 h), and late response (24 h) genes upon treatment. Changes in ALOX5AP, TXN, and SOD1 expression suggested that DU385 causes oxidative stress, which was confirmed by depletion of cellular glutathione and mitochondrial membrane depolarization induction. Imidazo[1,2-b]pyrazole-7-carboxamides reported herein induced apoptosis in human leukemia cells at nanomolar concentrations.

Therapeutic potential of root and stem bark of wild medicinal plant Ziziphus mauritiana (Lamk.) against silica induced toxicity in Wistar albino rats

ETHNOPHARMACOLOGICAL RELEVANCE

Ziziphus mauritiana (Lamk.) of the family Rhamnaceae is a traditional herbal medicinal plant commonly called as 'ber' (Indian jujube). It is traditionally used as food source and helps in treatment of various diseases like malaria, asthma, diarrhoea, typhoid, diabetes, skin diseases and acts as a pain killer.

AIM OF THE STUDY

This study aimed to evaluate the ability of extracts of barks of root and stem of Ziziphus mauritiana (ZM) to cure silica induced toxicity in Wistar albino rats.

MATERIALS AND METHODS

Experiments carried out on the acute toxicity studies of silica and therapeutic potential of ZM extracts were based on OECD guidelines and from these results lethal dose (LD₅₀) values were determined. Silica was administered by IP injection at 20 mg/kg b.w. for 10 days and roots and stem barks extracts of ZM were fed orally by gavage at 400 mg/kg b.w. for 21 days. Assessments of biochemical, haematological parameters as well as liver histological examination were performed in the study.

RESULTS

After 21 days of oral feeding of extracts of root and stem of ZM, it was found to alter the liver histology. Significant decrease in enzymes such as ALT, AST, ALP, LDH and urea, creatinine and uric acid levels in serum were recorded. Treatment with extracts could help enzymatic activity of liver antioxidant enzymes to settle towards normal level and significant decrease in the lipid peroxidation along with increase in the value of GSH in liver, was also observed. In addition, extracts of ZM also helped to reduce the serum NO, IL-6 and TNF-α level.

CONCLUSION

Results of this study has suggested that the extracts of root and stem bark of ZM can be used for therapeutic purpose to prevent silica induced toxicity. ZM extracts could be utilised as natural antioxidant and immunotherapeutic medicines to protect silica induced cell damage.

Effect of autophagy-associated proteins on the arecoline-induced liver injury in mice

Arecoline can be used to treat diseases including glaucoma and tapeworm infection, however, long-term administration can cause severe adverse effects, including oral submucosal fibrosis, oral cancer, hepatic injury and liver cancer. Autophagy serves a role in these injuries. The present study established a mouse model of arecoline-induced hepatic injury and investigated the role of autophagy-associated proteins in this injury. The results indicated that the expression levels of the autophagy marker protein microtubule associated protein 1 light chain 3 B (MAP1LC3B) and autophagy-promoting protein beclin 1 were elevated in the injured hepatic cells, while the expression levels of a well-known negative regulator of autophagy, mammalian target of rapamycin (mTOR), were reduced. Following treatment of the hepatic injury with glutathione, the liver function improved and liver damage was reduced effectively. Compared with the control group, the expression levels of both MAP1LC3B and beclin 1 were significantly upregulated in the glutathione-treated mice, but the expression of mTOR was significantly downregulated. It may be concluded that in the process of protecting against arecoline-induced hepatic injury, glutathione cooperates with mTOR and beclin 1 to accelerate autophagy, maintaining stable cell morphology and cellular functions.

Glutathione Reduction of Patulin-Evoked Cytotoxicity in HEK293 Cells by the Prevention of Oxidative Damage and the Mitochondrial Apoptotic Pathway

Patulin (PAT) is a mycotoxin frequently detected in moldy fruits and fruit products. This study investigated the protective role of glutathione (GSH), an antioxidant agent, against PAT-induced cytotoxicity and its potential mechanisms in HEK293 cells. The obtained results showed that the addition of GSH significantly increased cell viability and decreased apoptosis induced by PAT. Additionally, GSH decreased intracellular ROS and mitochondrial ROS overproduction, suppressed the decline of the mitochondrial membrane potential, and maintained cellular ATP contents. GSH prevented the impairment of mitochondrial oxidative-phosphorylation system and, especially, enhanced the mRNA and protein levels of electron-transport-chain complex III (UQCRC2) and complex V (ATP5, ATP6 and ATP8). Furthermore, GSH increased endogenous GSH contents; enhanced the antioxidant-enzyme activities of SOD, CAT, GR, and GPx; and modulated oxidative damage. These results suggest that GSH reduces PAT-induced cytotoxicity via inhibition of oxidative damage and the mitochondrial apoptotic pathway in HEK293 cells.

Separation of circadian- and behavior-driven metabolite rhythms in humans provides a window on peripheral oscillators and metabolism

Shift workers, whose schedules are misaligned relative to their suprachiasmatic nuclei (SCN) circadian pacemaker, are at elevated risk of metabolic disorders. In a study of simulated day- versus night-shift work followed by a constant routine, we separated plasma-circulating metabolites according to whether their 24-h rhythms aligned with the central SCN pacemaker or instead reflected externally imposed behavioral schedules. We found that rhythms in many metabolites implicated in food metabolism dissociated from the SCN pacemaker rhythm, with the vast majority aligning with the preceding sleep/wake and feeding/fasting cycles. Our metabolomics study yields insight into the link between prolonged exposure to shift work and the spectrum of associated metabolic disorders by providing a window into peripheral oscillators and the biobehavioral factors that orchestrate them.

Misalignment between internal circadian rhythmicity and externally imposed behavioral schedules, such as occurs in shift workers, has been implicated in elevated risk of metabolic disorders. To determine underlying mechanisms, it is essential to assess whether and how peripheral clocks are disturbed during shift work and to what extent this is linked to the central suprachiasmatic nuclei (SCN) pacemaker and/or misaligned behavioral time cues. Investigating rhythms in circulating metabolites as biomarkers of peripheral clock disturbances may offer new insights. We evaluated the impact of misaligned sleep/wake and feeding/fasting cycles on circulating metabolites using a targeted metabolomics approach. Sequential plasma samples obtained during a 24-h constant routine that followed a 3-d simulated night-shift schedule, compared with a simulated day-shift schedule, were analyzed for 132 circulating metabolites. Nearly half of these metabolites showed a 24-h rhythmicity under constant routine following either or both simulated shift schedules. However, while traditional markers of the circadian clock in the SCN—melatonin, cortisol, and PER3 expression—maintained a stable phase alignment after both schedules, only a few metabolites did the same. Many showed reversed rhythms, lost their rhythms, or showed rhythmicity only under constant routine following the night-shift schedule. Here, 95% of the metabolites with a 24-h rhythmicity showed rhythms that were driven by behavioral time cues externally imposed during the preceding simulated shift schedule rather than being driven by the central SCN circadian clock. Characterization of these metabolite rhythms will provide insight into the underlying mechanisms linking shift work and metabolic disorders.

Commonly used thiol-containing antioxidants reduce cardiac differentiation and alter gene expression ratios of sarcomeric isoforms

Reactive oxygen species (ROS) scavengers such as beta-mercaptoethanol (BME) and monothiol glycerol (MTG) are extensively used in stem cell research to prevent cellular oxidative stress. However, how these antioxidant supplements impact stem cell cardiac differentiation, a process regulated by redox-signaling remains unknown. In this study, we found that removal of BME from the conventional high-glucose, serum-based differentiation medium improved cardiac differentiation efficiency by 2-3 fold. BME and MTG treatments during differentiation significantly reduced mRNA expression of cardiac progenitor markers (NKX2.5 and ISL1) as well as sarcomeric markers (MLC2A, MLC2V, TNNI3, MYH6 and MYH7), suggesting reduced cardiomyogenesis by BME or MTG. Moreover, BME and MTG altered the expression ratios between the sarcomeric isoforms. In particular, TNNI3 to TNNI1 ratio and MLC2V to MLC2A ratio were significantly lower in BME or MTG treated cells than untreated cells, implying altered cardiomyocyte phenotype and maturity. Lastly, BME and MTG treatments resulted in less frequent beating, slower contraction and relaxation velocities than untreated cells. Interestingly, none of the above-mentioned effects was observed with Trolox, a non-thiol based antioxidant, despite its strong antioxidant activity. This work demonstrates that commonly used antioxidant supplements may cause considerable changes to cellular redox state and the outcome of differentiation.

Small Delivery Vehicles of siRNA for Enhanced Cancer Targeting

Small interfering RNA (siRNA) drugs have been considered to treat various diseases in major organs. However, siRNA drugs developed for cancer therapy are hindered from proceeding to the clinic. To date, various delivery formulations have been developed from cationic lipids, polymers, and/or inorganic nanoparticles for systemic siRNA delivery to solid tumors. Most of these delivery vehicles do not generate small particle sizes and pharmacokinetics required for accumulation in target cancer cells compared with clinically tested anticancer drug-loaded polymeric micelles. This review describes the significance of small, long-circulating vehicles for efficient delivery of siRNA to cancer tissues via the enhanced permeability and retention (EPR) effect. We summarize recent biological evidence that supports the size effect of delivery vehicles in tumor microenvironments and introduce promising strategies for the construction of small vehicles with sizes of 10-50 nm. We then discuss the feasibility of these delivery vehicles with respect to translation to clinical trials.

Tuned Density of Anti-Tissue Factor Antibody Fragment onto siRNA-Loaded Polyion Complex Micelles for Optimizing Targetability into Pancreatic Cancer Cells

Antibody fragment (Fab')-installed polyion complex (PIC) micelles were constructed to improve targetability of small interfering RNA (siRNA) delivery to pancreatic cancer cells. To this end, we synthesized a block copolymer of azide-functionalized poly(ethylene glycol) and poly(l-lysine) and prepared PIC micelles with siRNA. Then, a dibenzylcyclooctyne (DBCO)-modified antihuman tissue factor (TF) Fab' was conjugated to azido groups on the micellar surface. A fluorescence correlation spectroscopic analysis revealed that 1, 2, or 3 molecule(s) of Fab'(s) were installed onto one micellar nanoparticle according to the feeding ratio of Fab' (or DBCO) to micelle (or azide). The resulting micelles exhibited ∼40 nm in hydrodynamic diameter, similar to that of the parent micelles before Fab' conjugation. Flow cytometric analysis showed that three molecules of Fab'-installed PIC micelles (3(Fab')-micelles) had the highest binding affinity to cultured pancreatic cancer BxPC3 cells, which are known to overexpress TF on their surface. The 3(Fab')-micelles also exhibited the most efficient gene silencing activity against polo-like kinase 1 mRNA in the cultured cancer cells. Furthermore, the 3(Fab')-micelles exhibited high penetrability and the highest cellular internalization amounts in BxPC3 spheroids compared with one or two molecule(s) of Fab'-installed PIC micelles. These results demonstrate the potential of anti-TF Fab'-installed PIC micelles for active targeting of stroma-rich pancreatic tumors.

HDAC and Ku70 axis- an effective target for apoptosis induction by a new 2-cyano-3-oxo-1,9-dien glycyrrhetinic acid analogue

Methyl 2-cyano-3,12-dioxo-18β-olean-1,9(11)-dien-30-oate (CDODO-Me, 10d) derived from glycyrrhetinic acid and methyl-2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO-Me) derived from oleanoic acid are potent apoptosis inducers developed to clinical trials. Both compounds have high affinity for reduced  glutathione (GSH), which needs to be overcome to improve their target selectivity. We generated a new 10d analogue methyl 2-cyano-3-oxo-18β-olean-1,9(11), 12-trien-30-oate (COOTO, 10e), which retains high apoptosis inducing ability, while displaying decreased affinity for GSH, and explored the acting targets. We found that it induces Noxa level, reduces c-Flip level and causes Bax/Bak activation. Silencing of either Noxa or Bak significantly attenuated apoptosis induction of 10e. We linked these events due to targeting HDAC3/HDAC6 and Ku70 axis. 10e treatment reduced the levels of HDAC3 and HDAC6 with increased DNA damage/repair marker gamma-H2AX (γ-H2AX) and acetylated Ku70. c-Flip dissociates from acetylated Ku70 undergoing degradation, while Bax dissociates from acetylated Ku70 undergoing activation. Silencing of either HDAC3 or HDAC6 enhanced 10e-induced apoptosis. We reveal a new action cascade of this category of compounds that involves targeting of HADC3/6 proteins and Ku70 acetylation.

Till Death Do Us Part: The Marriage of Autophagy and Apoptosis

Autophagy is a widely conserved catabolic process that is necessary for maintaining cellular homeostasis under normal physiological conditions and driving the cell to switch back to this status quo under times of starvation, hypoxia, and oxidative stress. The potential similarities and differences between basal autophagy and stimulus-induced autophagy are still largely unknown. Both act by clearing aberrant or unnecessary cytoplasmic material, such as misfolded proteins, supernumerary and defective organelles. The relationship between reactive oxygen species (ROS) and autophagy is complex. Cellular ROS is predominantly derived from mitochondria. Autophagy is triggered by this event, and by clearing the defective organelles effectively, it lowers cellular ROS thereby restoring cellular homeostasis. However, if cellular homeostasis cannot be reached, the cells can switch back and choose a regulated cell death response. Intriguingly, the autophagic and cell death machines both respond to the same stresses and share key regulatory proteins, suggesting that the pathways are intricately connected. Here, the intersection between autophagy and apoptosis is discussed with a particular focus on the role ROS plays.

Aldo-keto reductases-mediated cytotoxicity of 2-deoxyglucose: A novel anticancer mechanism

2‐Deoxyglucose (2DG) is a non‐metabolizable glucose analog currently in clinical trials to determine its efficacy in enhancing the therapeutic effects of radiotherapy and chemotherapy of several types of cancers. It is thought to preferentially kill cancer cells by inhibiting glycolysis because cancer cells are more dependent on glycolysis for their energy needs than normal cells. However, we found that the toxicity of 2DG in cancer cells is mediated by the enzymatic activities of AKR1B1 and/or AKR1B10 (AKR1Bs), which are often overexpressed in cancer cells. Our results show that 2DG kills cancer cells because, in the process of being reduced by AKR1Bs, depletion of their cofactor NADPH leads to the depletion of glutathione (GSH) and cell death. Furthermore, we showed that compounds that are better substrates for AKR1Bs than 2DG are more effective than 2DG in killing cancer cells that overexpressed these 2 enzymes. As cancer cells can be induced to overexpress AKR1Bs, the anticancer mechanism we identified can be applied to treat a large variety of cancers. This should greatly facilitate the development of novel anticancer drugs.

Glutathione: Antioxidant Properties Dedicated to Nanotechnologies

Which scientist has never heard of glutathione (GSH)? This well-known low-molecular-weight tripeptide is perhaps the most famous natural antioxidant. However, the interest in GSH should not be restricted to its redox properties. This multidisciplinary review aims to bring out some lesser-known aspects of GSH, for example, as an emerging tool in nanotechnologies to achieve targeted drug delivery. After recalling the biochemistry of GSH, including its metabolism pathways and redox properties, its involvement in cellular redox homeostasis and signaling is described. Analytical methods for the dosage and localization of GSH or glutathiolated proteins are also covered. Finally, the various therapeutic strategies to replenish GSH stocks are discussed, in parallel with its use as an addressing molecule in drug delivery.

Quantitative Proteomic Analysis of Cellular Responses to a Designed Amino Acid Feed in a Monoclonal Antibody Producing Chinese Hamster Ovary Cell Line

Background:

Chinese hamster ovary (CHO) cell line is considered as the most common cell line in the biopharmaceutical industry because of its capability in performing efficient post-translational modifications and producing the recombinant proteins, which are similar to natural human proteins. The optimization of the upstream process via different feed strategies has a great impact on the target molecule expression and yield.

Methods:

To determine and understand the molecular events beneath the feed effects on the CHO cell, a label-free quantitative proteomic analysis was applied. The proteome changes followed by the addition of a designed amino acid feed to the monoclonal antibody producing CHO cell line culture medium were investigated.

Results:

The glutathione synthesis, the negative regulation of the programmed cell death, proteasomal catabolic process, and the endosomal transport pathway were up-regulated in the group fed with a designed amino acid feed compared to the control group.

Conclusion:

Our findings could be helpful to identify new targets for metabolic engineering.

Nanoparticle-cell interactions induced apoptosis: a case study with nanoconjugated epidermal growth factor

In addition to the intrinsic toxicity associated with the chemical composition of nanoparticles (NP) and their ligands, biofunctionalized NP can perturb specific cellular processes through NP-cell interactions and induce programmed cell death (apoptosis). In the case of the epidermal growth factor (EGF), nanoconjugation has been shown to enhance the apoptotic efficacy of the ligand, but the critical aspects of the underlying mechanism and its dependence on the NP morphology remain unclear. In this manuscript we characterize the apoptotic efficacy of nanoconjugated EGF as a function of NP size (with sphere diameters in the range 20-80 nm), aspect ratio (A.R., in the range of 4.5 to 8.6), and EGF surface loading in EGFR overexpressing MDA-MB-468 cells. We demonstrate a significant size and morphology dependence in this relatively narrow parameter space with spherical NP with a diameter of approx. 80 nm being much more efficient in inducing apoptosis than smaller spherical NP or rod-shaped NP with comparable EGF loading. The nanoconjugated EGF is found to trigger an EGFR-dependent increase in cytoplasmic reactive oxygen species (ROS) levels but no indications of increased mitochondrial ROS levels or mitochondrial membrane damage are detected at early time points of the apoptosis induction. The increase in cytoplasmic ROS is accompanied by a perturbation of the intracellular glutathione homeostasis, which represents an important check-point for NP-EGF mediated apoptosis. Abrogation of the oxidative stress through the inhibition of EGFR signaling by the EGFR inhibitor AG1478 or addition of antioxidants N-acetyl cysteine (NAC) or tempol, but not trolox, successfully suppressed the apoptotic effect of nanoconjugated EGF. A model to account for the observed morphology dependence of EGF nanoconjugation enhanced apoptosis and the underlying NP-cell interactions is discussed.

l-Glutamine Attenuates Apoptosis in Porcine Enterocytes by Regulating Glutathione-Related Redox Homeostasis

Background

Programmed cell death plays a fundamental role in intestinal development and mucosal homeostasis. Dysregulation of these processes is associated with an impaired intestinal-mucosal barrier, reduced nutrient absorption, and initiation and progression of intestinal diseases. 4-Hydroxy-2-nonenal (4-HNE), a product of lipid peroxidation, is commonly used to induce oxidative stress in cells. l-Glutamine is known to protect cells from apoptosis. However, the underlying mechanisms are largely unknown.

Objective

This study was conducted to test the hypothesis that l-glutamine attenuates 4-HNE-induced apoptosis by modulating glutathione (GSH) and thioredoxin (TXN) antioxidant systems and the expression of genes involved in 4-HNE metabolism in enterocytes.

Methods

Intestinal porcine epithelial cell line 1 (IPEC-1) cells were cultured with or without 4-HNE (30 μmol/L) in the presence of 0.05 or 0.25 mmol l-glutamine/L (a physiological concentration in the lumen of the small intestine) for indicated time periods. Cell viability, abundances of apoptotic proteins, mitochondrial membrane depolarization, production of reactive oxygen species (ROS) and GSH, and expression of genes involved in the biosynthesis of GSH, thioredoxin, and 4-HNE metabolism were determined.

Results

Compared with basal medium containing 0.05 mmol l-glutamine/L, 4-HNE enhanced apoptosis by 19.6% (P < 0.05) in a caspase-3-dependent manner. This effect was accompanied by elevated intracellular ROS production (39.5% and 85.3% for 2- and 4-h treatment, respectively), increased mitochondrial depolarization by 80%, and decreased intracellular GSH concentrations by 17.7%. These effects of 4-HNE were reduced by 0.25 mmol l-glutamine/L. Further study showed that the protective effect of l-glutamine was associated with the enhanced expression of genes involved in GSH production (including GCLC, GCLM, GSR, CBS, and CTH) by 3.9-14-fold, as well as genes involved in 4-HNE metabolism [e.g., glutathione S-transferase A (GSTA)1 and GSTA4] by 1.9-7.2-fold. The mRNA levels for ADH5, AKR1C1, AKR1A1, and TXNRD1 were enhanced 1.4-8.8-fold by 4-HNE but were not changed in cells co-treated with 4-HNE and l-glutamine.

Conclusion

These findings indicate that l-glutamine attenuates 4-HNE-induced apoptosis by regulating GSH-related redox homeostasis and enhancing GSTA-mediated metabolism in enterocytes.

A cAMP analog attenuates beta-amyloid (1-42)-induced mitochondrial dysfunction and spatial learning and memory deficits

Alzheimer's disease (AD), a neurodegenerative disorder in elderly, is indicated with deposition of Amyloid β (Aβ) in the brain and accompanied with cognitive impairment. Bucladesine, a phosphodiesterase inhibitor, may ameliorate AD's cognitive dysfunctions through mimicking the action of cAMP and raising its intracellular level. Here, we investigated the effects of bucladesine on Aβ-induced memory and learning impairment in a Morris water maze (MWM) model. Rats were injected with bucladesine (1 μl/side from a 100 μM stock solution) and Aβ (1 μl/side from a 100 μM stock solution) intra-hippocampally and after 19 days were trained for 4 successive days. The oxidative stress was evaluated through measurement of thiobarbituric acid (TBARS), thiol groups, and ferric reducing antioxidant power (FRAP). Effect of Aβ and its combination with bucladesine on the mitochondrial function was assessed according to changes in the ROS generation, mitochondrial membrane potential (MMP), mitochondrial swelling, ATP/ADP ratio, mitochondrial outer membrane damage and cytochrome C release. Our results showed a significant elevation in TBARS level after administration of Aβ causing mitochondrial ROS generation, swelling, outer membrane damage, cytochrome C release and also lower thiol, FRAP, and MMP levels. Aβ-induced spatial memory impairment was prevented by pre-treatment with bucladesine and the changed mitochondrial and biochemical indices upon treatment dose were improved. Taken together, we have obtained satisfactory results suggesting protecting effects of bucladesine against the Aβ-mediated memory deficit and implying its plausible beneficial capacity as a therapeutic agent in oxidative stress-associated neurodegenerative diseases.

Self-assembled nanomicelles of amphiphilic clotrimazole glycyl-glycine analogue augmented drug delivery, apoptosis and restrained melanoma tumour progression

In present investigation, self-assembled nanomicelles of amphiphilic clotrimazole glycyl-glycine (CLT-GG-SANMs) analogue were customized for augmenting drug delivery, permeability and apoptosis in B16F1 mouse melanoma cancer cells both in vitro and in vivo following intratumoral (i.t.) route of administration. The mean particle size of CLT-GG-SANMs was measured to be 35.9 ± 3.4 nm in addition to zeta-potential of -17.1 ± 3.5 mV. The shape of CLT-GG-SANMs was visualized to be smooth and spherical as like nanoparticles. The critical micellar concentration (CMC) of CLT-GG-SANMs was estimated to be 17 μg/ml using DPH (1,6-diphenyl-1,3,5-hexatriene) as a UV probe. Modification of CLT to CLT-GG-SANMs induced the amorphization in therapeutic moiety. Next, CLT suspension released only 9.7% of the drug within 1 h under dissolution testing and further analysis up to 48 h did not display any remarkable effect on the drug release. On the other hand, CLT-GG-SANMs released 46.2% of the drug significantly (P < 0.01) higher than CLT suspension at 4 h. The IC₅₀ of CLT-GG-SANMs was measured to be 15.1-μM significantly (P < 0.05) lower than CLT suspension (IC₅₀ > 20 μM) in B16F1 cells. Western blotting and histopathological analysis also supported the superior therapeutic efficacy of CLT-GG-SANMs in terms of higher extent of apoptosis, tumour regression and exhibition of strong antioxidant potential against B16F1 cells induced tumour in C57BL6J mice. In conclusion, in vitro and in vivo therapeutic efficacy analysis indicated that CLT-GG-SANMs may be a potential candidate for translating in to a clinically viable product.

Changes in Oxidant Defense, Apoptosis, and Cognitive Abilities During Treatment for Childhood Leukemia

Aggressive central nervous system (CNS)-directed treatment for acute lymphoblastic leukemia (ALL), the most prevalent cancer among children and adolescents, prevents metastasis of leukemia cells into the brain. Up to 60% of survivors experience cognitive problems, but knowledge about risk factors for and mechanisms of neurologic injury is lacking. Objectives of the present study were to (1) quantify changes in oxidant defense and apoptosis over the course of ALL therapy and (2) elucidate risk factors for long-term cognitive problems. The sample included 71 children with ALL. Cerebrospinal fluid (CSF) samples were collected at diagnosis and during intrathecal chemotherapy administration. Oxidant defense was measured by reduced glutathione (GSH), oxidized glutathione (GSSG), and the ratio of GSH:GSSG. Apoptosis was measured by activity of several cysteine-dependent aspartate-specific protease (abbreviated as caspase) enzymes that initiate (caspases 8 and 9) or execute (caspases 3/7) apoptosis. Cognitive abilities were assessed by standardized measures of short-term memory, visual-motor integration, and attention 3 years after ALL diagnosis. GSH and GSSG concentration increased significantly during ALL therapy, and a low GSH:GSSG ratio was indicative of an oxidized extracellular environment. Caspase enzyme activity increased significantly, and caspases 3/7 activity was significantly and negatively associated with performance on measures of cognitive abilities. Younger age at time of ALL diagnosis was associated with some measures of attention. Efflux of glutathione into CSF maintains oxidant defense by scavenging free radicals and other reactive oxygen species and is an early event in apoptosis. These mechanisms may be involved in neurologic injury associated with CNS-directed treatment and subsequent cognitive problems.

Reducible disulfide poly(beta-amino ester) hydrogels for antioxidant delivery

Recently, biomaterials have been designed to contain redox-sensitive moieties, such as thiols and disulfides, to impart responsive degradation and/or controlled release. However, due to the high sensitivity of cellular redox-based systems which maintain free-radical homeostasis (e.g. glutathione/glutathione disulfide), if these biomaterials modify the cellular redox environment, they may inadvertently affect cellular compatibility and/or oxidative stress defenses. In this work, we hypothesize that the degradation products of a poly(β-amino ester) (PBAE) hydrogel formed with redox sensitive disulfide (cystamine) crosslinking could serve as a supplement to the environmental cellular antioxidant defenses. Upon introduction into a reducing environment, these disulfide-containing hydrogels cleave to present bound-thiol groups, yet remain in the bulk form at up to 66 mol% cystamine of the total amines. By controlling the molar fraction of cystamine, it was apparent that the thiol content varied human umbilical vein endothelial cell (HUVEC) viability IC₅₀ values across an order of magnitude. Further, upon introduction of an enzymatic oxidative stress generator to the cell culture (HX/XO), pre-incubated thiolated hydrogel degradation products conferred cellular and mitochondrial protection from acute oxidative stress, whereas non-reduced disulfide-containing degradation products offered no protection. This polymer may be an advantageous implantable drug delivery system for use in acute oxidative stress prophylaxis and/or chronic oxidative stress cell therapies due to its solid/liquid reversibility in a redox environment, controlled thiolation, high loading capacity through covalent drug-addition, and simple post-synthesis modification which bound-thiols introduce.

STATEMENT OF SIGNIFICANCE

In this work, we demonstrate a unique property of disulfide containing degradable biomaterials. By changing the redox state of the degradation products (from oxidized to reduced), it is possible to increase the IC₅₀ of the material by an order of magnitude. This dramatic shift is linked directly to the oxidative stress response of the cells and suggests a possible mechanism by which one can tune the cellular response to degradable biomaterials.

Antioxidant and anti-proliferative properties of extracts from heterotrophic cultures of Galdieria sulphuraria

This study explores the possibility to use the extremophilic microalga Galdieria sulphuraria (strain 064) as a source of natural biomolecules with beneficial and protective effects on human health. Galdieria was cultivated in heterotrophy conditions and cells extracts for their antioxidant and anti-proliferative properties were tested. Galdieria extracts showed high antioxidant power tested through ABTS assay and revealed high glutathione and phycocyanin contents. Based on Annexin-V FITC/propidium iodide and MTT analysis, algae extracts inhibited the proliferation of human adenocarcinoma A549 cells (51.2% inhibition) through the induction of apoptosis without cell cycle arrest. Besides, cytotoxicity and cytometry assays showed a positive pro-apoptotic mechanism. On these bases, we suggest that G. sulphuraria from heterotrophic culture, for its therapeutic potential, could be considered a good candidate for further studies with the aim to isolate bioactive anti-cancer molecules.

Copper as a target for prostate cancer therapeutics: copper-ionophore pharmacology and altering systemic copper distribution

Copper-ionophores that elevate intracellular bioavailable copper display significant therapeutic utility against prostate cancer cells in vitro and in TRAMP (Transgenic Adenocarcinoma of Mouse Prostate) mice. However, the pharmacological basis for their anticancer activity remains unclear, despite impending clinical trails. Herein we show that intracellular copper levels in prostate cancer, evaluated in vitro and across disease progression in TRAMP mice, were not correlative with copper-ionophore activity and mirrored the normal levels observed in patient prostatectomy tissues (Gleason Score 7 & 9). TRAMP adenocarcinoma cells harbored markedly elevated oxidative stress and diminished glutathione (GSH)-mediated antioxidant capacity, which together conferred selective sensitivity to prooxidant ionophoric copper. Copper-ionophore treatments [CuII(gtsm), disulfiram & clioquinol] generated toxic levels of reactive oxygen species (ROS) in TRAMP adenocarcinoma cells, but not in normal mouse prostate epithelial cells (PrECs). Our results provide a basis for the pharmacological activity of copper-ionophores and suggest they are amendable for treatment of patients with prostate cancer. Additionally, recent in vitro and mouse xenograft studies have suggested an increased copper requirement by prostate cancer cells. We demonstrated that prostate adenocarcinoma development in TRAMP mice requires a functional supply of copper and is significantly impeded by altered systemic copper distribution. The presence of a mutant copper-transporting Atp7b protein (tx mutation: A4066G/Met1356Val) in TRAMP mice changed copper-integration into serum and caused a remarkable reduction in prostate cancer burden (64% reduction) and disease severity (grade), abrogating adenocarcinoma development. Implications for current clinical trials are discussed.

A pilot study comparing the metabolic profiles of elite-level athletes from different sporting disciplines

Background

The outstanding performance of an elite athlete might be associated with changes in their blood metabolic profile. The aims of this study were to compare the blood metabolic profiles between moderate- and high-power and endurance elite athletes and to identify the potential metabolic pathways underlying these differences.

Methods

Metabolic profiling of serum samples from 191 elite athletes from different sports disciplines (121 high- and 70 moderate-endurance athletes, including 44 high- and 144 moderate-power athletes), who participated in national or international sports events and tested negative for doping abuse at anti-doping laboratories, was performed using non-targeted metabolomics-based mass spectroscopy combined with ultrahigh-performance liquid chromatography. Multivariate analysis was conducted using orthogonal partial least squares discriminant analysis. Differences in metabolic levels between high- and moderate-power and endurance sports were assessed by univariate linear models.

Results

Out of 743 analyzed metabolites, gamma-glutamyl amino acids were significantly reduced in both high-power and high-endurance athletes compared to moderate counterparts, indicating active glutathione cycle. High-endurance athletes exhibited significant increases in the levels of several sex hormone steroids involved in testosterone and progesterone synthesis, but decreases in diacylglycerols and ecosanoids. High-power athletes had increased levels of phospholipids and xanthine metabolites compared to moderate-power counterparts.

Conclusions

This pilot data provides evidence that high-power and high-endurance athletes exhibit a distinct metabolic profile that reflects steroid biosynthesis, fatty acid metabolism, oxidative stress, and energy-related metabolites. Replication studies are warranted to confirm differences in the metabolic profiles associated with athletes’ elite performance in independent data sets, aiming ultimately for deeper understanding of the underlying biochemical processes that could be utilized as biomarkers with potential therapeutic implications.

Electronic supplementary material

The online version of this article (10.1186/s40798-017-0114-z) contains supplementary material, which is available to authorized users.

Mitophagy in TGEV infection counteracts oxidative stress and apoptosis

The intestinal epithelial cells contain a large number of mitochondria for persisting absorption and barrier function. Selective autophagy of mitochondria (mitophagy) plays an important role in the quality control of mitochondria and maintenance of cell homeostasis. Transmissible gastroenteritis virus (TGEV) is a porcine enteropathogenic coronavirus which induces malabsorption and lethal watery diarrhea in suckling piglets. The role of mitophagy in the pathological changes caused by TGEV infection is unclear. Here, we report that TGEV induces mitophagy to suppress oxidative stress and apoptosis induced by viral infection in porcine epithelial cells (IPEC-J2). We observe that TGEV infection induce mitochondrial injury, abnormal morphology, complete mitophagy, and without obvious apoptosis after TGEV infection. Meanwhile, TGEV also induces DJ-1 and some antioxidant genes upregulation to suppress oxidative stress induced by viral infection. Furthermore, silencing DJ-1 inhibit mitophagy and increase apoptosis after TGEV infection. In addition, we demonstrate for the first time that viral nucleocapsid protein (N) is located in mitochondria and mitophagosome during virus infection or be expressed alone. Those results provide a novel perspective for further improvement of prevention and treatment in TGEV infection. These results suggest that TGEV infection induce mitophagy to promote cell survival and possibly viral infection.

Various cellular stress components change as the rat ages: An insight into the putative overall age-related cellular stress network

Cellular stress is mainly comprised of oxidative, nitrosative, and endoplasmic reticulum stresses and has long been correlated to the ageing process. Surprisingly, the age-related difference among the various components in each independent stress pathway and the possible significance of these components in relation to the overall cellular stress network remain to be clearly elucidated. In this study, we obtained blood from ageing rats upon reaching 20-, 40-, and 72-wk.-old. Subsequently, we measured representative cellular stress-linked biomolecules (H₂O₂, glutathione reductase, heme, NADPH, NADP, nitric oxide, GADD153) and cell signals [substance P (SP), free fatty acid, calcium, NF-κB] in either or both blood serum and cytosol. Subsequently, network analysis of the overall cellular stress network was performed. Our results show that there are changes affecting stress-linked biomolecules and cell signals as the rat ages. Additionally, based on our network analysis data, we postulate that NADPH, H₂O₂, GADD153, and SP are the key components and the interactions between these components are central to the overall age-related cellular stress network in the rat blood. Thus, we propose that the main pathway affecting the overall age-related cellular stress network in the rat blood would entail NADPH-related oxidative stress (involving H₂O₂) triggering GADD153 activation leading to SP induction which in-turn affects other cell signals.