Glutathione depletion regulates both extrinsic and intrinsic apoptotic signaling cascades independent from multidrug resistance protein 1

Nanotechnology-integrated ferroptosis inducers: a sharp sword against tumor drug resistance

Presently, the biggest hurdle to cancer therapy is the inevitable emergence of drug resistance. Since conventional therapeutic schedules fall short of the expectations in curbing drug resistance, the development of novel drug resistance management strategies is critical. Extensive research over the last decade has revealed that the process of ferroptosis is correlated with cancer resistance; moreover, it has been demonstrated that ferroptosis inducers reverse drug resistance. To elucidate the development and promote the clinical transformation of ferroptosis strategies in cancer therapy, we first analyzed the roles of key ferroptosis-regulating molecules in the progression of drug resistance in-depth and then reviewed the design of ferroptosis-inducing strategies based on nanotechnology for overcoming drug resistance, including glutathione depletion, reactive oxygen species generation, iron donation, lipid peroxidation aggregation, and multiple-drug resistance-associated tumor cell destruction. Finally, the prospects and challenges of regulating ferroptosis as a therapeutic strategy for reversing cancer therapy resistance were evaluated. This review aimed to provide a comprehensive understanding for researchers to develop ferroptosis-inducing nanoplatforms that can overcome drug resistance.

SIRT3 and Metabolic Reprogramming Mediate the Antiproliferative Effects of Whey in Human Colon Cancer Cells

Emerging strategies to improve healthy aging include dietary interventions as a tool to promote health benefits and reduce the incidence of aging-related comorbidities. The health benefits of milk are also linked to its richness in betaines and short-chain acylcarnitines, which act synergistically in conferring anticancer, anti-inflammatory, and antioxidant properties. Whey, despite being a dairy by-product, still has a considerable content of bioactive betaines and acylcarnitines. Here, we investigated the anticancer properties of whey from Mediterranean water buffalo (Bubalus bubalis) milk by testing its antiproliferative effects in colorectal cancer (CRC) cells HT-29, HCT 116, LoVo and SW480. Results indicated that treatment with whey for 72 h inhibited cell proliferation (p < 0.001), induced cell cycle arrest, and apoptosis via caspase-3 activation, and modulated cell metabolism by limiting glucose uptake and interfering with mitochondrial energy metabolism with the highest effects observed in HT-29 and HCT 116 cells. At molecular level, these effects were accompanied by upregulation of sirtuin 3 (SIRT3) (p < 0.01) and peroxisome proliferator-activated receptor (PPAR)-γ expression (p < 0.001), and downregulation of lactate dehydrogenase A (LDHA) (p < 0.01), sterol regulatory-element binding protein 1 (SREBP1) (p < 0.05), and PPAR-α (p < 0.01). Transient SIRT3 gene silencing blocked the effects of whey on the LDHA, PPAR-γ, and PPAR-α protein expressions (p < 0.01) suggesting that the whey capacity of perturbating the metabolic homeostasis in CRC cell lines is mediated by SIRT3.

NAC and Vitamin D Improve CNS and Plasma Oxidative Stress in Neonatal HIE and Are Associated with Favorable Long-Term Outcomes

N-acetylcysteine (NAC) and vitamin D provide effective neuroprotection in animal models of severe or inflammation-sensitized hypoxic ischemic encephalopathy (HIE). To translate these FDA-approved drugs to HIE neonates, we conducted an early phase, open-label trial of 10 days of NAC (25, 40 mg/kg q12h) + 1,25(OH)2D (calcitriol 0.05 mg/kg q12h, 0.03 mg/kg q24h), (NVD), for pharmacokinetic (PK) estimates during therapeutic hypothermia and normothermia. We paired PK samples with pharmacodynamic (PD) targets of plasma isoprostanoids, CNS glutathione (GSH) and total creatine (tCr) by serial MRS in basal ganglia (BG) before and after NVD infusion at five days. Infants had moderate (n = 14) or severe HIE (n = 16), funisitis (32%), and vitamin D deficiency (75%). NVD resulted in rapid, dose-responsive increases in CNS GSH and tCr that correlated positively with plasma [NAC], inversely with plasma isofurans, and was greater in infants with lower baseline [GSH] and [tCr], suggesting increases in these PD markers were titrated by neural demand. Hypothermia and normothermia altered NAC PK estimates. NVD was well tolerated. Excluding genetic syndromes (2), prolonged ECMO (2), lost-to-follow-up (1) and SIDS death (1), 24 NVD treated HIE infants have no evidence of cerebral palsy, autism or cognitive delay at 24-48 months. These data confirm that low, safe doses of NVD in HIE neonates decreased oxidative stress in plasma and CNS, improved CNS energetics, and are associated with favorable developmental outcomes at two to four years.

A sensitive and rapid detection of glutathione based on a fluorescence-enhanced "turn-on" strategy

Glutathione (GSH) plays important roles in the human body including protecting cells from oxidative damages and maintaining cellular redox homeostasis. Thus, developing a fast and sensitive method for detecting GSH levels in living bodies is of great importance. Many methods have been developed and used for GSH detection, such as high-performance liquid chromatography, capillary electrophoresis, and fluorescence resonance energy-based methods. However, these methods often lack sensitivity as well as efficiency. Herein, a rapid and sensitive method for glutathione detection was developed based on a fluorescence-enhanced "turn-on" strategy. In this study, a unique and versatile bifunctional linker 3-[(2-aminoethyl) dithio]propionic acid (AEDP)-modified gold nanoparticle (Au@PLL-AEDP-FITC) probe was designed for the simple, highly sensitive intracellular GSH detection, combined with the FRET technique. In the presence of GSH, the disulfide bonds of AEDP on Au@PLL-AEDP-FITC were broken through competition with GSH, and FITC was separated from gold nanoparticles, making the fluorescence signal switch to the "turn on" state. A change in the fluorescence signal intensity has a great linear positive correlation with GSH concentration, in the linear range from 10 nM to 180 nM (R2 = 0.9948), and the limit of detection (LOD) of 3.07 nM, which was lower than other reported optical nanosensor-based methods. Au@PLL-AEDP-FITC also has great selectivity for GSH, making it promising for application in complex biological systems. The Au@PLL-AEDP-FITC probe was also successfully applied in intracellular GSH imaging in HeLa cells with confocal microscopy. In short, the Au@PLL-AEDP-FITC probe-based fluorescence-enhanced "turn-on" strategy is a sensitive, fast, and effective method for GSH detection as compared with other methods. It can be applied in complex biological systems such as cell systems, with promising biological-medical applications in the future.

The role of ginsenoside Rb1, a potential natural glutathione reductase agonist, in preventing oxidative stress-induced apoptosis of H9C2 cells

Background

Oxidative stress-induced cardiomyocytes apoptosis is a key pathological process in ischemic heart disease. Glutathione reductase (GR) reduces glutathione disulfide to glutathione (GSH) to alleviate oxidative stress. Ginsenoside Rb1 (GRb1) prevents the apoptosis of cardiomyocytes; however, the role of GR in this process is unclear. Therefore, the effects of GRb1 on GR were investigated in this study.

Methods

The antiapoptotic effects of GRb1 were evaluated in H9C2 cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, annexin V/propidium iodide staining, and Western blotting. The antioxidative effects were measured by a reactive oxygen species assay, and GSH levels and GR activity were examined in the presence and absence of the GR inhibitor 1,3-bis-(2-chloroethyl)-1-nitrosourea. Molecular docking and molecular dynamics simulations were used to investigate the binding of GRb1 to GR. The direct influence of GRb1 on GR was confirmed by recombinant human GR protein.

Results

GRb1 pretreatment caused dose-dependent inhibition of tert-butyl hydroperoxide-induced cell apoptosis, at a level comparable to that of the positive control N-acetyl-L-cysteine. The binding energy between GRb1 and GR was positive (−6.426 kcal/mol), and the binding was stable. GRb1 significantly reduced reactive oxygen species production and increased GSH level and GR activity without altering GR protein expression in H9C2 cells. Moreover, GRb1 enhanced the recombinant human GR protein activity in vitro, with a half-maximal effective concentration of ≈2.317 μM. Conversely, 1,3-bis-(2-chloroethyl)-1-nitrosourea co-treatment significantly abolished the GRb1's apoptotic and antioxidative effects of GRb1 in H9C2 cells.

Conclusion

GRb1 is a potential natural GR agonist that protects against oxidative stress–induced apoptosis of H9C2 cells.

Multifaceted Roles of Glutathione and Glutathione-Based Systems in Carcinogenesis and Anticancer Drug Resistance

SIGNIFICANCE

Glutathione is the most abundant antioxidant molecule in living organisms and has multiple functions. Intracellular glutathione homeostasis, through its synthesis, consumption, and degradation, is an intricately balanced process. Glutathione levels are often high in tumor cells before treatment, and there is a strong correlation between elevated levels of intracellular glutathione/sustained glutathione-mediated redox activity and resistance to pro-oxidant anticancer therapy. Recent Advances: Ample evidence demonstrates that glutathione and glutathione-based systems are particularly relevant in cancer initiation, progression, and the development of anticancer drug resistance.

CRITICAL ISSUES

This review highlights the multifaceted roles of glutathione and glutathione-based systems in carcinogenesis, anticancer drug resistance, and clinical applications.

FUTURE DIRECTIONS

The evidence summarized here underscores the important role played by glutathione and the glutathione-based systems in carcinogenesis and anticancer drug resistance. Future studies should address mechanistic questions regarding the distinct roles of glutathione in different stages of cancer development and cancer cell death. It will be important to study how metabolic alterations in cancer cells can influence glutathione homeostasis. Sensitive approaches to monitor glutathione dynamics in subcellular compartments will be an indispensible step. Therapeutic perspectives should focus on mechanism-based rational drug combinations that are directed against multiple redox targets using effective, specific, and clinically safe inhibitors. This new strategy is expected to produce a synergistic effect, prevent drug resistance, and diminish doses of single drugs. Antioxid. Redox Signal. 27, 1217-1234.

Chronic toxicological effects of β-diketone antibiotics on Zebrafish (Danio rerio) using transcriptome profiling of deep sequencing

Transcriptome analysis is important for interpreting the functional elements of the genome and revealing the molecular constituents of cells and tissues. Herein, differentially transcribed genes were identified by deep sequencing after zebrafish (Danio rerio) were exposed to β-diketone antibiotics (DKAs); 23,129 and 23,550 mapped genes were detected in control and treatment groups, a total of 3238 genes were differentially expressed between control and treatment groups. Of these genes, 328 genes (213 up- and 115 down-regulation) had significant differential expression (p < 0.05) and an expression ratio (control/treatment) of >2 or <0.5. Additionally, we performed Gene Ontology (GO) category and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, and found 266 genes in the treatment group with annotation terms linked to the GO category. A total of 77 differentially expressed transcriptional genes were associated with 132 predicted KEGG metabolic pathways. Serious liver tissue damage was reflected and consistent with the differences in genetic classification and function from the transcriptome analysis. These results enhance our understanding of zebrafish developmental processes under exposure to DKA stress. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1357-1371, 2016.

Molecular Changes in the Nasal Cavity after N, N-dimethyl-p-toluidine Exposure

N, N-dimethyl-p-toluidine (DMPT; Cas No. 99-97-8), an accelerant for methyl methacrylate monomers in medical devices, is a nasal cavity carcinogen according to a 2-yr cancer study of male and female F344/N rats, with the nasal tumors arising from the transitional cell epithelium. In this study, we exposed male F344/N rats for 5 days to DMPT (0, 1, 6, 20, 60, or 120 mg/kg [oral gavage]) to explore the early changes in the nasal cavity after short-term exposure. Lesions occurred in the nasal cavity including hyperplasia of transitional cell epithelium (60 and 120 mg/kg). Nasal tissue was rapidly removed and preserved for subsequent laser capture microdissection and isolation of the transitional cell epithelium (0 and 120 mg/kg) for transcriptomic studies. DMPT transitional cell epithelium gene transcript patterns were characteristic of an antioxidative damage response (e.g., Akr7a3, Maff, and Mgst3), cell proliferation, and decrease in signals for apoptosis. The transcripts of amino acid transporters were upregulated (e.g., Slc7a11). The DMPT nasal transcript expression pattern was similar to that found in the rat nasal cavity after formaldehyde exposure, with over 1,000 transcripts in common. Molecular changes in the nasal cavity after DMPT exposure suggest that oxidative damage is a mechanism of the DMPT toxic and/or carcinogenic effects.

Loss of Mrp1 Potentiates Doxorubicin-Induced Cytotoxicity in Neonatal Mouse Cardiomyocytes and Cardiac Fibroblasts

Doxorubicin (DOX) induces dose-dependent cardiotoxicity in part due to its ability to induce oxidative stress. We showed that loss of multidrug resistance-associated protein 1 (Abcc1/Mrp1) potentiates DOX-induced cardiac dysfunction in mice in vivo Here, we characterized DOX toxicity in cultured cardiomyocytes (CM) and cardiac fibroblasts (CF) derived from C57BL wild type (WT) and Mrp1 null (Mrp1-/-) neonatal mice. CM accumulated more intracellular DOX relative to CF but this accumulation did not differ between genotypes. Following DOX (0.3-4 μM), Mrp1-/- CM, and CF, especially CM, showed a greater decrease in viability and increased apoptosis and DNA damage, demonstrated by higher caspase 3 cleavage, poly (ADP-ribose) polymerase 1 (PARP) cleavage and phosphorylated histone H2AX (γH2AX) levels versus WT cells. Saline- and DOX-treated Mrp1-/- cells had significantly higher intracellular GSH and GSSG compared with WT cells (P < .05), but the redox potential (Eh) of the GSH/GSSG pool did not differ between genotypes in CM and CF, indicating that Mrp1-/- cells maintain this major redox couple. DOX increased expression of the rate-limiting GSH synthesis enzyme glutamate-cysteine ligase catalytic (GCLc) and regulatory subunits (GCLm) to a significantly greater extent in Mrp1-/- versus WT cells, suggesting adaptive responses to oxidative stress in Mrp1-/- cells that were inadequate to afford protection. Expression of extracellular superoxide dismutase (ECSOD/SOD3) was lower (P < .05) in Mrp1-/- versus WT CM treated with saline (62% ± 8% of WT) or DOX (43% ± 12% of WT). Thus, Mrp1 protects CM in particular and CF against DOX-induced toxicity, potentially by regulating extracellular redox states.

Glutathione-induced drought stress tolerance in mung bean: coordinated roles of the antioxidant defence and methylglyoxal detoxification systems

Drought is considered one of the most acute environmental stresses presently affecting agriculture. We studied the role of exogenous glutathione (GSH) in conferring drought stress tolerance in mung bean (Vigna radiata L. cv. Binamoog-1) seedlings by examining the antioxidant defence and methylglyoxal (MG) detoxification systems and physiological features. Six-day-old seedlings were exposed to drought stress (-0.7 MPa), induced by polyethylene glycol alone and in combination with GSH (1 mM) for 24 and 48 h. Drought stress decreased seedling dry weight and leaf area; resulted in oxidative stress as evidenced by histochemical detection of hydrogen peroxide (H2O2) and [Formula: see text] in the leaves; increased lipid peroxidation (malondialdehyde), reactive oxygen species like H2O2 content and [Formula: see text] generation rate and lipoxygenase activity; and increased the MG level. Drought decreased leaf succulence, leaf chlorophyll and relative water content (RWC); increased proline (Pro); decreased ascorbate (AsA); increased endogenous GSH and glutathione disulfide (GSSG) content; decreased the GSH/GSSG ratio; increased ascorbate peroxidase and glutathione S-transferase activities; and decreased the activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and catalase. The activities of glyoxalase I (Gly I) and glyoxalase II (Gly II) increased due to drought stress. In contrast to drought stress alone, exogenous GSH enhanced most of the components of the antioxidant and glyoxalase systems in drought-affected mung bean seedlings at 24 h, but GSH did not significantly affect AsA, Pro, RWC, leaf succulence and the activities of Gly I and DHAR after 48 h of stress. Thus, exogenous GSH supplementation with drought significantly enhanced the antioxidant components and successively reduced oxidative damage, and GSH up-regulated the glyoxalase system and reduced MG toxicity, which played a significant role in improving the physiological features and drought tolerance.

Effects of 940 MHz EMF on bioluminescence and oxidative response of stable luciferase producing HEK cells

Oxidative stress and response are among EMF mechanisms of action; the absorbed dose and ability of cells to respond might be summarized by the intracellular luciferase activity.