Depletion Of Intracellular GSH Research Articles

Biodegradable copper-doped calcium phosphate nanoplatform enables tumor microenvironment modulations for amplified ferroptosis in cervical carcinoma treatment.

As a recently discovered form of regulated cell death, ferroptosis has attracted much attention in the field cancer therapy. However, achieving considerably enhanced efficacy is often restricted by the overexpression of endogenous glutathione (GSH) in tumor microenvironment (TME). In this work, we report a ferroptosis-inducing strategy of GSH depletion and reactive oxygen species (ROS) generation based on a biodegradable copper-doped calcium phosphate (CaP) with L-buthionine sulfoximine (BSO) loading (denoted as BSO@CuCaP-LOD, BCCL). BCCL was conducted by a biomineralization approach using lactate oxidases (LOD) as a bio-template to obtain Cu-doped CaP nanoparticles. Then, BSO was loaded to form BCCL nanoparticles with pH-responsive biodegradability to endow controlled release of Cu2+ and BSO in response to acidic TME. Benefiting from the catalytic performance of LOD, BCCL efficiently depletes the level of lactate in tumor, which can generate endogenous H2O2 for subsequent Fenton-like reaction. The Cu2+ and BSO intracellular GSH depletion followed by GSH-mediated Cu2+/Cu+ conversion, leading to the inhibition of glutathione peroxidase 4 (GPX4) and generation of •OH radicals via Cu+-mediated Fenton-like reaction. BCCL confers enhanced ferroptosis induction via intracellular LOD-induced H2O2 production, BSO-mediated GSH depletion, and Cu+-mediated ROS generation, leading to cause effective ferroptotic cell damage. As verified by in vitro and in vivo assays, the designed BCCL nanoplatform is highly biocompatible and exhibits superior anticancer therapy on uterine cervical carcinoma U14 tumor xenografts. This study, therefore, provides a biocompatible therapeutic platform that modulating the TME to enable intensive ROS generating efficacy and GSH depleting performance, as well as provides an innovative paradigm for achieving effective ferroptosis-based cancer therapy.

Catabolism of extracellular glutathione supplies amino acids to support tumor growth.

Restricting amino acids from tumors is an emerging therapeutic strategy with significant promise. While typically considered an intracellular antioxidant with tumor-promoting capabilities, glutathione (GSH) is a tripeptide of cysteine, glutamate, and glycine that can be catabolized, yielding amino acids. The extent to which GSH-derived amino acids are essential to cancers is unclear. Here, we find that GSH catabolism promotes tumor growth. We show that depletion of intracellular GSH does not perturb tumor growth, and extracellular GSH is highly abundant in the tumor microenvironment, highlighting the potential importance of GSH outside of tumors. We find supplementation with GSH can rescue cancer cell survival and growth in cystine-deficient conditions, and this rescue is dependent on the catabolic activity of γ-glutamyltransferases (GGTs). Finally, pharmacologic targeting of GGTs' activity prevents the breakdown of circulating GSH, lowers tumor cysteine levels, and slows tumor growth. Our findings indicate a non-canonical role for GSH in supporting tumors by acting as a reservoir of amino acids. Depriving tumors of extracellular GSH or inhibiting its breakdown is potentially a therapeutically tractable approach for patients with cancer. Further, these findings change our view of GSH and how amino acids, including cysteine, are supplied to cells.

Alginate-functionalized and 4T1 cell membrane-coated multi-tasking nanoparticulate system for near-infrared-triggered photodynamic therapy on breast cancer: In vitro cellular and in vivo mice models

Recently, combination treatment of chemo-dynamic therapy (CDT) and photodynamic therapies (PDT) is well-known and prominent therapeutic strategy for breast tumor. Importantly, tailored nanomedicines with unique personalized properties including nanocarrier suitability and effective targeting ability that requires the exhaustive understanding of tumor microenvironment. Recently, researchers have designed a smart upconversion nanoparticles (UCNPs) that have unique characteristics to achieve targeting for respond tumor microenvironment. In the present study, we first time fabricated a novel combination of oxidized sodium alginate-enveloped and 4T1 cancer cell membrane-coated up-conversion nanoparticles (4TUCNP@SMZ) were engineered for breast cancer-targeted therapy. The nanoparticles could be formed via electrostatic interaction, which showed excellent biocompatibility, increased cellular uptake with normal and cancer cells. The fabricated Alginate and 4T1-membrane functionalized up-conversion nanoparticles significantly benefitted to targeted delivery system for local breast cancer and prominently inhibit tumor development via chemo-dynamic therapy (CDT) and PDT. The greater susceptibility of tumor cells to oxidative stress may also result from the depletion of intracellular GSH by the 4TUCNP@SMZ nanoparticles. The in vitro cell models (4T1 and MCF-7), in vivo tumor model and histological observation demonstrated that 4TUCNP@SMZ nanoparticles effectively targeted to breast tumor microenvironment and inhibit breast cancer cells. This report suggested that multifunctional Alginate-functionalized nanoparticles are a versatile agent for phototherapy for breast cancer treatment.

Pro-Oxidant Auranofin and Glutathione-Depleting Combination Unveils Synergistic Lethality in Glioblastoma Cells with Aberrant Epidermal Growth Factor Receptor Expression.

Glioblastoma (GBM) is the most prevalent and advanced malignant primary brain tumor in adults. GBM frequently harbors epidermal growth factor receptor (EGFR) wild-type (EGFRwt) gene amplification and/or EGFRvIII activating mutation. EGFR-driven GBM relies on the thioredoxin (Trx) and/or glutathione (GSH) antioxidant systems to withstand the excessive production of reactive oxygen species (ROS). The impact of EGFRwt or EGFRvIII overexpression on the response to a Trx/GSH co-targeting strategy is unknown. In this study, we investigated Trx/GSH co-targeting in the context of EGFR overexpression in GBM. Auranofin is a thioredoxin reductase (TrxR) inhibitor, FDA-approved for rheumatoid arthritis. L-buthionine-sulfoximine (L-BSO) inhibits GSH synthesis by targeting the glutamate-cysteine ligase catalytic (GCLC) enzyme subunit. We analyzed the mechanisms of cytotoxicity of auranofin and the interaction between auranofin and L-BSO in U87MG, U87/EGFRwt, and U87/EGFRvIII GBM isogenic GBM cell lines. ROS-dependent effects were assessed using the antioxidant N-acetylsteine. We show that auranofin decreased TrxR1 activity and increased ROS. Auranofin decreased cell vitality and colony formation and increased protein polyubiquitination through ROS-dependent mechanisms, suggesting the role of ROS in auranofin-induced cytotoxicity in the three cell lines. ROS-dependent PARP-1 cleavage was associated with EGFRvIII downregulation in U87/EGFRvIII cells. Remarkably, the auranofin and L-BSO combination induced the significant depletion of intracellular GSH and synergistic cytotoxicity regardless of EGFR overexpression. Nevertheless, molecular mechanisms associated with cytotoxicity were modulated to a different extent among the three cell lines. U87/EGFRvIII exhibited the most prominent ROS increase, P-AKT(Ser-473), and AKT decrease along with drastic EGFRvIII downregulation. U87/EGFRwt and U87/EGFRvIII displayed lower basal intracellular GSH levels and synergistic ROS-dependent DNA damage compared to U87MG cells. Our study provides evidence for ROS-dependent synergistic cytotoxicity of auranofin and L-BSO combination in GBM in vitro. Unraveling the sensitivity of EGFR-overexpressing cells to auranofin alone, and synergistic auranofin and L-BSO combination, supports the rationale to repurpose this promising pro-oxidant treatment strategy in GBM.

Amplification of Oxygen-Independent Free Radicals Based on a Glutathione Depletion and Biosynthesis Inhibition Strategy for Photothermal and Thermodynamic Therapy of Hypoxic Tumors.

Thermodynamic therapy (TDT) based on oxygen-independent free radicals exhibits promising potential for the treatment of hypoxic tumors. However, its therapeutic efficacy is seriously limited by the premature release of the drug and the free radical scavenging effect of glutathione (GSH) in tumors. Herein, we report a GSH depletion and biosynthesis inhibition strategy using EGCG/Fe-camouflaged gold nanorod core/ZIF-8 shell nanoparticles embedded with azo initiator 2,2'-azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride (AIPH) and L-buthionine-sulfoximine (BSO) for tumor-targeting photothermal (PTT) and thermodynamic therapy (TDT). This nanoplatform (GNR@ZIF-8-AIPH/BSO@EGCG/Fe, GZABEF) endows a pH-responsive release performance. With the 67 kDa lamin receptor (67LR)-targeting ability of EGCG, GZABEF could selectively release oxygen-independent free radicals in tumor cells under 1064 nm laser irradiation. More importantly, Fe3+-mediated GSH depletion and BSO-mediated GSH biosynthesis inhibition significantly boosted the accumulation of alkyl radicals. In 4T1 cells, GZABEF induced cancer cell death via intracellular GSH depletion and GSH peroxidase 4 (GPX4) inactivation. In a subcutaneous xenograft model of 4T1, GZABEF demonstrated remarkable tumor growth inhibition (78.2%). In addition, excellent biosafety and biocompatibility of GZABEF were observed both in vitro and in vivo. This study provides inspiration for amplified TDT/PTT-mediated antitumor efficacy.

PEGylated chitosan-coated nanophotosensitizers for effective cancer treatment by photothermal-photodynamic therapy combined with glutathione depletion

The combination of photothermal therapy (PTT) and photodynamic therapy (PDT) has emerged as a promising strategy for cancer treatment. However, the poor photostability and photothermal conversion efficiency (PCE) of organic small-molecule photosensitizers, and the intracellular glutathione (GSH)-mediated singlet oxygen scavenging largely decline the antitumor efficacy of PTT and PDT. Herein, a versatile nanophotosensitizer (NPS) system is developed by ingenious incorporation of indocyanine green (ICG) into the PEGylated chitosan (PEG-CS)-coated polydopamine (PDA) nanoparticles via multiple π-π stacking, hydrophobic and electrostatic interactions. The PEG-CS-covered NPS showed prominent colloidal and photothermal stability as well as high PCE (ca 62.8 %). Meanwhile, the Michael addition between NPS and GSH can consume GSH, thus reducing the GSH-induced singlet oxygen scavenging. After being internalized by CT26 cells, the NPS under near-infrared laser irradiation produced massive singlet oxygen with the aid of thermo-enhanced intracellular GSH depletion to elicit mitochondrial damage and lipid peroxide formation, thus leading to ferroptosis and apoptosis. Importantly, the combined PTT and PDT delivered by NPS effectively inhibited CT26 tumor growth in vivo by light-activated intense hyperthermia and redox homeostasis disturbance. Overall, this work presents a new tactic of boosting antitumor potency of ICG-mediated phototherapy by PEG-CS-covered NPS.

Nanosensors Monitor Intracellular GSH Depletion: GSH Triggers Cu(II) for Tumor Imaging and Inhibition.

Glutathione (GSH) is the primary antioxidant in cells, and GSH consumption will break the redox balance in cells. Based on this, a method that uses high concentrations of GSH in the tumor microenvironment to trigger the redox reaction of Cu(II) to generate copper nanoprobes with fluorescence and tumor growth inhibition properties is proposed. The nanoprobe mainly exists in the form of Cu(I) and catalyzes the decomposition of hydrogen peroxide into hydroxyl radicals. At the same time, a simple and controllable carbon micro-nano electrode is used to construct a single-cell sensing platform, which enable the detection of glutathione content in single living cells after Cu(II) treatment, providing an excellent example for detecting single-cell biomolecules.

Copper peroxide nanodot-decorated gold nanostar/silica nanorod Janus nanostructure with NIR-II photothermal and acid-triggered hydroxyl radical generation properties for the effective treatment of wound infections.

Recently, bacterial infections have become a global crisis, greatly threatening the health of human beings. The development of a non-antibiotic biomaterial is recognized as an alternative way for the effective treatment of bacterial infections. In the present work, a multifunctional copper peroxide (CP) nanodot-decorated gold nanostar (GNS)/silica nanorod (SiNR) Janus nanostructure (GNS@CP/SiNR) with excellent antibacterial activity was reported. Due to the formation of the Janus nanostructure, GNS@CP/SiNR displayed strong plasmonic resonance absorbance in the near infrared (NIR)-II region that enabled the nanosystem to achieve mild photothermal therapy (MPTT). In acidic conditions, CP decorated on GNS@CP/SiNR dissociated rapidly by releasing Cu2+ and H2O2, which subsequently transformed to ˙OH via the Fenton-like reaction for chemodynamic therapy (CDT). As a result, GNS@CP/SiNR could effectively inhibit both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), and eradicate the associated bacterial biofilms by exerting the synergistic MPTT/CDT antibacterial effect. Moreover, GNS@CP/SiNR was also demonstrated to be effective in treating wound infections, as verified on the S. aureus-infected full thickness excision wound rat model. Our mechanism study revealed that the synergistic MPTT/CDT effect of GNS@CP/SiNR firstly caused bacterial membrane damage, followed by boosting intracellular ROS via the severe oxidative stress effect, which subsequently caused the depletion of intracellular GSH and DNA damage, finally leading to the death of bacteria.

An In Situ Chemotherapy Drug Combined with Immune Checkpoint Inhibitor for Chemoimmunotherapy.

Clinically, cancer chemotherapy still faces unsatisfactory efficacy due to drug resistance and severe side effects, including tiredness, hair loss, feeling sick, etc. The clinical benefits of checkpoint inhibitors have revived hope for cancer immunotherapy, but the objective response rate of immune checkpoint inhibitors remains around 10-40%. Herein, two types of copper-doped mesoporous silica nanoparticles (MS-Cu-1 with a diameter of about 30 nm and MS-Cu-2 with a diameter of about 200 nm) were synthesized using a one-pot method. Both MS-Cu-1 and MS-Cu-2 nanoparticles showed excellent tumor microenvironment regulation properties with elevated extracellular and intracellular ROS generation, extracellular and intracellular oxygenation, and intracellular GSH depletion. In particular, MS-Cu-2 nanoparticles demonstrated a better microenvironment modulation effect than MS-Cu-1 nanoparticles. The DSF/MS-Cu composites with disulfiram (DSF) and copper co-delivery characteristics were prepared by a straightforward method using chloroform as the solvent. Cell survival rate and live/dead staining results showed that DSF and MS-Cu alone were not toxic to LLC cells, while a low dose of DSF/MS-Cu (1-10 μg/mL) showed a strong cell-killing effect. In addition, MS-Cu-2 nanoparticles released more Cu2+ in a weakly acidic environment (pH = 5) than in a physiological environment (pH = 7.4), and the Cu2+ released was 41.72 ± 0.96 mg/L in 1 h under weakly acidic conditions. UV-visible absorption spectrometry confirmed the production of tumor-killing drugs (CuETs). The intratumoral injection of DSF/MS-Cu significantly inhibited tumor growth in vivo by converting nontoxic DSF/MS-Cu into toxic CuETs. The combination of DSF/MS-Cu and anti-CTLA-4 antibody further inhibited tumor growth, showing the synergistic effect of DSF/MS-Cu and immune checkpoint inhibitors.

PH-Responsive Sorafenib/Iron-Co-Loaded Mesoporous Polydopamine Nanoparticles for Synergistic Ferroptosis and Photothermal Therapy.

Ferroptosis has attracted significant attention as a new mechanism of cell death. Sorafenib (SRF) is widely considered a prototypical ferroptosis-inducing drug, particularly for liver cancer treatment. However, the low solubility and hydrophobic nature of SRF, along with the absence of synergistic therapeutic strategies, still limit its application in cancer treatment. Herein, we report a dual therapeutic method incorporating photothermal therapy and ferroptosis by using Fe-doped mesoporous polydopamine nanoparticles (Fe-mPDA@SRF-TPP) as a carrier for loading SRF and targeting triphenylphosphine (TPP). SRF molecules are efficiently encapsulated within the polydopamine nanospheres with a high loading ratio (80%) attributed to the porosity of Fe-mPDA, and the inherent biocompatibility and hydrophilicity of Fe-mPDA@SRF-TPP facilitate the transport of SRF to the target cancer cells. Under the external stimuli of acidic environment (pH 5.0), glutathione (GSH), and laser irradiation, Fe-mPDA@SRF-TPP shows sustained release of SRF and Fe ions with the ratio of 72 and 50% within 48 h. Fe-mPDA@SRF-TPP nanoparticles induce intracellular GSH depletion, inhibit glutathione peroxidase 4 (GPX4) activity, and generate hydroxyl radicals, all of which are essential components of the therapeutic ferroptosis process for killing MDA-MB-231 cancer cells. Additionally, the excellent near-infrared (NIR) light absorption of Fe-mPDA@SRF-TPP nanoparticles demonstrates their capability for photothermal therapy and further enhances the therapeutic efficiency. Therefore, this nanosystem provides a multifunctional therapeutic platform that overcomes the therapeutic limitations associated with standalone ferroptosis and enhances the therapeutic efficacy of SRF for breast cancer.

A Novel Polyamino Acid Sulfur Dioxide Prodrug Synergistically Elevates ROS with β-Lapachone in Cancer Treatment

Due to the distorted redox balance, cancer cells are considered more vulnerable to excessive reactive oxygen species (ROS). In a variety of oxidative stress-related therapies, gas therapy has emerged as a new therapeutic strategy owing to its efficacy and biosafety. Herein, a newly-discovered gasotransmitter sulfur dioxide (SO2) and a tumor specific ROS generation agent β-lapachone (Lapa) were firstly combined for anticancer therapy. Firstly, amphiphilic glutathione (GSH) responsive polypeptide SO2 prodrug PEG-b-poly(Lys-DNs) was synthesized by ring opening polymerization of SO2-containing N-carboxyanhydride. Then, Lapa was encapsulated into the polymeric micelles with loading content of 8.6 % and loading efficiency of 51.6 %. The obtained drug-loaded nanoparticles (NPs(Lapa)) exhibited a fast release of Lapa and SO2 in the stimuli of 10 mM GSH in PBS. Subsequently, in vitro experiment showed that NPs(Lapa) exhibited obvious cytotoxicity towards 4 T1 cancer cells at a concentration of 2.0 μg/mL, which may be attributed to the depletion of intracellular GSH and upregulation of ROS level both by SO2 release and by the ROS generation from lapachone transformation. In vivo fluorescence imaging showed that the NPs were gradually enriched in tumor tissues in 24 h, probably due to the enhanced permeability and retention effect of NPs. Finally, NPs(Lapa) showed the best anticancer effect in 4 T1 tumor bearing mice with a tumor inhibiting rate (IRT) of 61 %, whereas IRT for free Lapa group was only 23.6 %. This work may be a new attempt to combine SO2 gas therapy with ROS inducer for anticancer therapy through oxidative stress.

Redox-Activatable Magnetic Nanoarchitectonics for Self-Enhanced Tumor Imaging and Synergistic Photothermal-Chemodynamic Therapy.

Oral squamous cell carcinoma (OSCC) is a prevalent malignancy of the head and neck region associated with high recurrence rates and poor prognosis under current diagnostic and treatment methods. The development of nanomaterials that can improve diagnostic accuracy and therapeutic efficacy is of great importance for OSCC. In this study, a redox-activatable nanoarchitectonics is designed via the construction of dual-valence cobalt oxide (DV-CO) nanospheres, which can serve as a contrast agent for magnetic resonance (MR) imaging, and exhibit enhanced transverse and longitudinal relaxivities through the release and redox of Co3+ /Co2+ in an acidic condition with glutathione (GSH), resulting in self-enhanced T1 /T2 -weighted MR contrast. Moreover, DV-CO demonstrates properties of intracellular GSH-depletion and hydroxyl radicals (•OH) generation through a Fenton-like reaction, enabling strengthened chemodynamic (CD) effect. Additionally, DV-CO displays efficient near-infrared laser-induced photothermal (PT) effect, thereby exhibiting synergistic PT-CD therapy for suppressing OSCC tumor cells. It further investigates the tumor-specific self-enhanced MR imaging of DV-CO both in subcutaneous and orthotopic OSCC mouse models, and demonstrate the therapeutic effects of DV-CO in orthotopic OSCC mouse models. Overall, the in vitro and in vivo findings highlight the excellent theranositc potentials of DV-CO for OSCC and offer new prospects for future advancement of nanomaterials.

Tumor microenvironment-activated, immunomodulatory nanosheets loaded with copper(II) and 5-FU for synergistic chemodynamic therapy and chemotherapy

The tumor microenvironment (TME) has a redox state that differs greatly from normal tissues, as characterized by the overexpression of H2O2 and glutathione (GSH). To address the GSH-related restrictions on chemodynamic therapy (CDT) efficacy, we have developed a Cu(II)-based CDT strategy. In this study, a novel organic–inorganic hybrid drug delivery system (LDH/HA/5-FU) was conceived and prepared by the intercalation of 5-FU into the interlayer of copper–aluminum layered double hydroxide (CuAl-LDH) via ion exchange strategy and the adsorption of hyaluronic acid (HA) on the surface of CuAl-LDH. Taking advantage of the pH-degradable property of CuAl-LDH and the CD44-targeting property of HA, the formed LDH/HA/5-FU nanosheets could specifically target tumor cells' overexpressing CD44 receptor, rapidly release Cu(II) and 5-FU in tumor cells, inducing tumor cell apoptosis and cuproptosis, and long-term intracellular GSH depletion and toxic hydroxyl radicals (·OH) generation could be achieved through the cyclic catalytic reaction of Cu(I)/Cu(II). Meanwhile, peritumoral injection of LDH/HA/5-FU nanosheets might function as an adjuvant to increase the levels of antitumor tumor-associated macrophages (TAMs) and T cells. In vivo experiments further verified that the intelligently designed LDH/HA/5-FU nanosheets successfully promoted the immune systems, with an excellent inhibition efficacy towards tumors by combining Cu-based CDT and chemotherapy, showing promising potential for solid tumor treatments.

An in situ self‐assembled peptide derivative for inhibition of glutathione synthesis and selective enhancement of tumor radiotherapy

AbstractBackgroundInhibition of glutathione (GSH) synthesis in cancer cells considerably improves the efficacy of reactive oxygen species (ROS)‐related tumor therapy. Self‐assembled peptide derivatives can facilitate the efficient delivery and accumulation of small molecular drugs in cancer cells.MethodsSelf‐assembling modules were covalently linked to the GSH‐biosynthesis inhibitor l‐buthionine sulfoximine (BSO) by solid‐phase synthesis to form the self‐assembling peptide derivative Nap‐DFDFpY‐GG‐BSO (Nano‐BSO@ in situ). Subsequently, its enzyme‐instructed self‐assembly in vitro and on cell surfaces were confirmed, and its intracellular GSH depletion and radiotherapy‐sensitizing effects were determined.ResultsNano‐BSO@ in situ successfully self‐assembles into a hydrogel with a nanofibrous microstructure upon incubation with alkaline phosphatase (ALP) at a critical concentration of 9.84 μM. Furthermore, it selectively self‐assembles in situ on HeLa cells with high ALP expression. At a concentration of 50 μM, Nano‐BSO@ in situ decreases intracellular GSH levels by 80%, ∼2.3 times more than free BSO. Meanwhile, pretreatment of HeLa cells with 50 μM Nano‐BSO@ in situ for 24 h results in a radiotherapy sensitization enhancement ratio to γ‐rays of 2.09.ConclusionsA novel in situ self‐assembling peptide derivative for GSH depletion and selective enhancement of tumor radiotherapy was constructed. The excellent GSH‐depletion ability and remarkable radiotherapy‐enhancement performance indicate that Nano‐BSO@ in situ is a promising selective sensitizer for ROS‐related treatment of tumor cells with high ALP expression.

Study on the antioxidant activity of peptides from soybean meal by fermentation based on the chemical method and AAPH-induced oxidative stress.

Preparation and antioxidant activities of soybean peptides using solid fermentation to decrease the content of trypsin inhibitor (TI) and antigen protein were investigated in this study. The results showed the optimal fermentation conditions were as follows: fermentation time 48 h, the ratio of material to solvent 1:2, inoculum size 12%, and the ratio of Lactic acid bacteria and Aspergillus oryzae 2:1. The hydrolysate was were divided into four components of <1, 1-3, 3-5, and >5 kDa by ultrafiltration based on molecular weight, and the <1 kDa peptides expressed the highest antioxidant activities. Meanwhile, the cell antioxidant activity of the <1 kDa soybean peptides was investigated using AAPH-induced erythrocyte hemolysis, which effectively inhibited erythrocyte hemolysis with the inhibit rate of 85.8% through inhibition of the ROS intracellular generation. In addition, soybean peptides could significantly restore the intracellular antioxidant enzymes (SOD, GSH-Px, and CAT) activities, as well as inhibited intracellular MDA generation and depletion of GSH. The intracellular antioxidant detoxifying mechanism of soybean peptides was associated with both non-enzymatic and enzymatic defense systems. According to this study, fermentation could effectively improve the antioxidant activities of soybean peptides.

Isotope tracing reveals bacterial catabolism of host-derived glutathione during Helicobacter pylori infection.

Mammalian cells synthesize the antioxidant glutathione (GSH) to shield cellular biomolecules from oxidative damage. Certain bacteria, including the gastric pathogen Helicobacter pylori, can perturb host GSH homeostasis. H. pylori infection significantly decreases GSH levels in host tissues, which has been attributed to the accumulation of reactive oxygen species in infected cells. However, the precise mechanism of H. pylori-induced GSH depletion remains unknown, and tools for studying this process during infection are limited. We developed an isotope-tracing approach to quantitatively monitor host-derived GSH in H. pylori-infected cells by mass spectrometry. Using this method, we determined that H. pylori catabolizes reduced GSH from gastric cells using γ-glutamyl transpeptidase (gGT), an enzyme that hydrolyzes GSH to glutamate and cysteinylglycine (Cys-Gly). gGT is an established virulence factor with immunomodulatory properties that is required for H. pylori colonization in vivo. We found that H. pylori internalizes Cys-Gly in a gGT-dependent manner and that Cys-Gly production during H. pylori infection is coupled to the depletion of intracellular GSH from infected cells. Consistent with bacterial catabolism of host GSH, levels of oxidized GSH did not increase during H. pylori infection, and exogenous antioxidants were unable to restore the GSH content of infected cells. Altogether, our results indicate that H. pylori-induced GSH depletion proceeds via an oxidation-independent mechanism driven by the bacterial enzyme gGT, which fortifies bacterial acquisition of nutrients from the host. Additionally, our work establishes a method for tracking the metabolic fate of host-derived GSH during infection.

Engineering of a GSH activatable photosensitizer for enhanced photodynamic therapy through disrupting redox homeostasis.

Although disrupted redox homeostasis has emerged as a promising approach for tumor therapy, most existing photosensitizers are not able to simultaneously improve the reactive oxygen species level and reduce the glutathione (GSH) level. Therefore, designing photosensitizers that can achieve these two aspects of this goal is still urgent and challenging. In this work, an organic activatable near-infrared (NIR) photosensitizer, CyI-S-diCF3, is developed for GSH depletion-assisted enhanced photodynamic therapy. CyI-S-diCF3, composed of an iodinated heptamethine cyanine skeleton linked with a recognition unit of 3,5-bis(trifluoromethyl)benzenethiol, can specifically react with GSH by nucleophilic substitution, resulting in intracellular GSH depletion and redox imbalance. Moreover, the activated photosensitizer can produce abundant singlet oxygen (1O2) under NIR light irradiation, further heightening the cellular oxidative stress. By this unique nature, CyI-S-diCF3 exhibits excellent toxicity to cancer cells, followed by inducing earlier apoptosis. Thus, our study may propose a new strategy to design an activatable photosensitizer for breaking the redox homeostasis in tumor cells.

Hypertoxic self-assembled peptide with dual functions of glutathione depletion and biosynthesis inhibition for selective tumor ferroptosis and pyroptosis

Abundant glutathione (GSH) is a biological characteristic of lots of tumor cells. A growing number of studies are utilizing GSH depletion as an effective adjuvant therapy for tumor. However, due to the compensatory effect of intracellular GSH biosynthesis, GSH is hard to be completely exhausted and the strategy of GSH depletion remains challenging. Herein, we report an l-buthionine-sulfoximine (BSO)-based hypertoxic self-assembled peptide derivative (NSBSO) with dual functions of GSH depletion and biosynthesis inhibition for selective tumor ferroptosis and pyroptosis. The NSBSO consists of a hydrophobic self-assembled peptide motif and a hydrophilic peptide derivative containing BSO that inhibits the synthesis of GSH. NSBSO was cleaved by GSH and thus experienced a morphological transformation from nanoparticles to nanofibers. NSBSO showed GSH-dependent cytotoxicity and depletion of intracellular GSH. In 4T1 cells with medium GSH level, it depleted intracellular GSH and inactivated GSH peroxidase 4 (GPX4) and thus induced efficient ferroptosis. While in B16 cells with high GSH level, it exhausted GSH and triggered indirect increase of intracellular ROS and activation of Caspase 3 and gasdermin E, resulting in severe pyroptosis. These findings demonstrate that GSH depletion- and biosynthesis inhibition-induced ferroptosis and pyroptosis strategy would provide insights in designing GSH-exhausted medicines.Graphical

SLC7A11/GPX4 Inactivation-Mediated Ferroptosis Contributes to the Pathogenesis of Triptolide-Induced Cardiotoxicity.

Triptolide exhibits promising efficacy in various cancers and immune diseases while its clinical application has been strongly restricted by its severe side effects, especially cardiotoxicity. However, the underlying mechanism of triptolide-induced cardiotoxicity (TIC) remains unclear. The RNA-seq analysis of triptolide-injured AC16 human cardiomyocyte cell line hinted that ferroptosis is involved in TIC. Further experimental validations proved that triptolide triggered ferroptosis, as evidenced by significant accumulation of lipid peroxidation (4-HNE and MDA levels) and ferrous iron, as well as depletion of intracellular GSH. Furthermore, triptolide-induced iron overload involved the upregulation of TF/TRFC/DMT1 signal axis and the degradation of ferritin, which contribute to ROS generation via Fenton reaction. In addition, inhibition of the antioxidant Nrf2/HO-1 pathway was observed in TIC, which may also lead to the overproduction of lethal lipid peroxides. Mechanistically, using streptavidin–biotin affinity pull-down assay and computational molecular docking, we unveiled that triptolide directly binds to SLC7A11 to inactivate SLC7A11/GPX4 signal axis. More importantly, employment of a ferroptosis inhibitor Ferrostatin-1 alleviated TIC by partially reversing the inhibitory effects of triptolide on SLC7A11/GPX4 signal. Altogether, our study demonstrated that SLC7A11/GPX4 inactivation-mediated ferroptosis contributed to the pathogenesis of TIC. Combating ferroptosis may be a promising therapeutic avenue to prevent TIC.

Glutathione Depletion‐Induced Activation of Dimersomes for Potentiating the Ferroptosis and Immunotherapy of “Cold” Tumor

AbstractThe abundant glutathione (GSH) in “cold” tumors weakens ferroptosis therapy and the immune response. Inspired by lipids, we fabricated cinnamaldehyde dimers (CDC) into lipid‐like materials to form dimersomes capable of depleting GSH and delivering therapeutics to potentiate the ferroptosis and immunotherapy of breast cancer. The dimersomes exhibited superior storage stability for over one year. After reaching the tumor, they quickly underwent breakage in the cytosol owing to the conjugation of hydrophilic GSH on CDC by Michael addition, which not only triggered the drug release and fluorescence switch “ON”, but also led to the depletion of intracellular GSH. Ferroptosis was significantly enhanced after combination with sorafenib (SRF) and elicited a robust immune response in vivo by promoting the maturation of dendritic cells and the priming of CD8+ T cells. As a result, the CDC@SRF dimersomes cured breast cancer in all the mice after four doses of administration.