Sepsis is a common complication of infections that significantly impacts the survival of critically patients. Currently, effective pharmacological treatment strategies are lacking. Auranofin, known as an inhibitor of Thioredoxin reductase (TrxR), exhibits anti-inflammatory activity, but its role in sepsis is not well understood. Here, we demonstrate the significant inhibitory effect of Auranofin on sepsis in a cecal ligation and puncture (CLP) mouse model. In vitro, Auranofin inhibits pyroptosis triggered by Caspase-11 activation. Further investigations reveal that inhibiting TrxR1 suppresses macrophage pyroptosis induced by E. coli, while TrxR2 does not exhibit this effect. TrxR1, functioning as a reductase, regulates the oxidative-reductive status of Thioredoxin-1 (Trx-1). Mechanistically, the modulation of Trx-1\'s reductive activity by TrxR1 may be involved in Caspase-11 activation-induced pyroptosis. Additionally, inhibiting TrxR1 maintains Trx-1 in its oxidized state. The oxidized form of Trx-1 interacts with Caveolin-1 (CAV1), regulating outer membrane vesicle (OMV) internalization. In summary, our study suggests that inhibiting TrxR1 suppresses OMV internalization by maintaining the oxidized form of Trx-1, thereby restricting Caspase-11 activation and alleviating sepsis.

Thioredoxin reductase (TrxR) is a pivotal regulator of redox homeostasis. It is frequently overexpressed in various cancer cells, including prostate cancer, making it a promising target for the development of anti-cancer drugs. In this study, we screened a series of newly designed complexes of gold(I) phosphine. Specifically, Compound 5 exhibited the highest cytotoxicity against prostate cancer cells and demonstrated stronger antitumor effects than commonly used drugs, such as cisplatin and auranofin. Importantly, our mechanistic study revealed that Compound 5 effectively inhibits the TrxR system in vitro. Additionally, Compound 5 promoted intracellular accumulation of reactive oxygen species (ROS), leading to mitochondrial dysfunction and irreversible apoptosis in prostate cancer cells. Our in vivo xenograft study further demonstrated that Compound 5 has excellent antitumor activity against prostate cancer cells, but does not cause severe side effects. These findings provide a promising lead Compound for the development of novel antitumor agents targeting prostate cancer and offer a valuable tool for investigating biological pathways involving TrxR and ROS modulation.

BACKGROUND: Early diagnosis of breast cancer is critical to the treatment and prognosis of breast cancer patients. Our aim is to explore more practical and effective diagnostic methods to facilitate early treatment and improve prognosis for breast cancer patients.
METHODS: The Mann-Whitney U test, receiver operating characteristic curve, Youden index, Chi-square test, and Fisher\'s exact test were used to determine whether plasma thioredoxin reductase (TrxR) could be used for the clinical diagnosis of breast cancer. The Wilcoxon signed-rank test was used to validate the prognostic potential of plasma TrxR activity assessment.
RESULTS: A total of 761 patients were included, including 537 cases of breast cancer and 224 cases of benign breast diseases. Plasma TrxR activity in the breast cancer group [8.0 (6.0, 9.45) U/mL] was significantly higher than that in the benign group [3.05 (1.20, 6.275) U/mL]. The diagnostic efficiency of TrxR for breast cancer was higher than that of other conventional breast cancer biomarkers, with an area under the curve of 0.821 (95% CI = 0.791-0.852). In addition, TrxR can be used in combination with conventional tumor markers to further improve the diagnostic efficiency. The optimal TrxR threshold for identifying benign and malignant diseases is 7.45 U/mL. We detected plasma TrxR activity and serum tumor markers before and after antitumor therapies in 333 breast cancer patients and found that their trends were basically the same, with a significant decrease in plasma TrxR activity after treatment.
CONCLUSIONS: Plasma TrxR activity can be used as a suitable biomarker for breast cancer diagnosis and efficacy assessment.

BACKGROUND: Oxidative stress is a pathological feature of acute coronary syndrome (ACS), a complex disease with varying clinical outcomes. Surrogate biomarkers of oxidative stress including, peroxiredoxin-2 (PRDX2), PRDX4, thioredoxin (TRX) and thioredoxin reductase (TRXR) were measured in ACS patients at presentation and follow-up, to assess their clinical utility in diagnosis and risk stratification.
METHODS: Plasma from 145 participants (80 ACS and 65 healthy) at diagnosis, 1-3 month (first) and 6-month follow-up (second) was analysed by ELISA. ACS patients were monitored for 12-months.
RESULTS: ACS patients at diagnosis had significantly higher concentrations of TRX (p < 0.05), TRXR (p < 0.01) and PRDX4 (p < 0.01), compared to healthy donors. This was increase was driven by non-ST elevated myocardial infarction for TRX (p < 0.01) and PRDX4 (p < 0.05). For TRXR, ACS females were significantly higher than males (p < 0.05). TRX was also higher in older females (>55 years) at diagnosis (p < 0.05). At first follow-up, TRX had lowered, whereas PRDX4 remained significantly high (p < 0.05). Stratification of ACS patients according to percutaneous coronary intervention (PCI) revealed that TRXR was significantly higher in patients receiving PCI to the right coronary artery (p < 0.05). Whereas both TRXR (p < 0.01) and PRDX4 (p < 0.01) were significantly higher in patients receiving PCI to the left anterior descending (LAD) artery. ACS patients who had plasma TRX >13.40 ng/ml at second follow-up were at high risk of readmission (p < 0.05), as were patients with TRXR of <1000 pg/ml at diagnosis having PCI to the LAD (p < 0.05).
CONCLUSIONS: This study indicates that TRX, TRXR and PRDX4 may have clinical utility for ACS stratification.

Objective: Most patients with osteosarcoma (OS) have an extremely poor prognosis. The primary purpose of this investigation was to explore the biological effect of Lnc-CLSTN2-1:1 on OS and the potential processes involved. Materials and procedures: We selected differentially overexpressed Lnc-CLSTN2-1:1 from our laboratory\'s existing RNA sequence analysis data (fibroblast osteoblast (hFOB 1.19) and three osteosarcoma cell lines (HOS, MG63, and U2OS) as the research object. Next, we detected Lnc-CLSTN2-1:1 in the osteosarcoma HOS cell line and fibroblast cells using qRT-PCR. We evaluated cell proliferation ability using EdU incorporation test, CCK-8 test, and cell clone formation; cell invasion and migration were assessed using the Transwell test, while flow cytometry examined cell cycle, apoptosis, and reactive oxygen species (ROS); Subsequently, the activity changes of selenase (GPx) glutathione peroxidase and (TrxR) thioredoxin reductase were detected. In addition, changes in related proteins were analyzed through Western blotting. Results: The expression of Lnc-CLSTN2-1:1 in osteosarcoma cells was significantly increased. The proliferation, invasion, and migration of osteosarcoma cells were significantly inhibited by knockdown of the expression of Lnc-CLSTN2-1:1, and the cell cycle-related signaling pathway PI3K/AKT/GSK-3β/cycinD1 was also inhibited. However, insulin-like growth factor-1 (igf-1) could reverse this process. In addition, we examined the activity of two selenophenases (TrxR and GPx) and the changes of ROS before and after Lnc-CLSTN2-1:1 knockdown. The results showed that both TrxR and GPx activities were reduced after Lnc-CLSTN2-1:1 knockdown, resulting in the inhibition of antioxidant stress levels, while intracellular ROS levels were high, which eventually caused killing effects on tumor cells due to the imbalance between oxidative stress and antioxidant stress. Conclusion: Our results showed that Lnc-CLSTN2-1:1 enhanced anti-oxidative stress TrxR and GPx selenoprotein activities through the PI3K/AKT signaling pathway while counteracting the loss of reactive oxygen species ROS produced by mitochondria to osteosarcoma cells, which protected osteosarcoma cells and thus promoted the proliferation and metastatic ability of OS.

High-grade serous ovarian cancer (HGSOC) accounts for 70% of ovarian cancer cases, and the survival rate remains remarkably low due to the lack of effective long-term consolidation therapies. Clinical remission can be temporarily induced by platinum-based chemotherapy, but death subsequently results from the extensive growth of a platinum-resistant component of the tumor. This work explores a novel treatment against HGSOC using the gold complex auranofin (AF). AF primarily functions as a pro-oxidant by inhibiting thioredoxin reductase (TrxR), an antioxidant enzyme overexpressed in ovarian cancer. We investigated the effect of AF on TrxR activity and the various mechanisms of cytotoxicity using HGSOC cells that are clinically sensitive or resistant to platinum. In addition, we studied the interaction between AF and another pro-oxidant, L-buthionine sulfoximine (L-BSO), an anti-glutathione (GSH) compound. We demonstrated that AF potently inhibited TrxR activity and reduced the vitality and viability of HGSOC cells regardless of their sensitivities to platinum. We showed that AF induces the accumulation of reactive oxygen species (ROS), triggers the depolarization of the mitochondrial membrane, and kills HGSOC cells by inducing apoptosis. Notably, AF-induced cell death was abrogated by the ROS-scavenger N-acetyl cysteine (NAC). In addition, the lethality of AF was associated with the activation of caspases-3/7 and the generation of DNA damage, effects that were also prevented by the presence of NAC. Finally, when AF and L-BSO were combined, we observed synergistic lethality against HGSOC cells, which was mediated by a further increase in ROS and a decrease in the levels of the antioxidant GSH. In summary, our results support the concept that AF can be used alone or in combination with L-BSO to kill HGSOC cells regardless of their sensitivity to platinum, suggesting that the depletion of antioxidants is an efficient strategy to mitigate the course of this disease.

BACKGROUND: It has been reported that activation of glutamate kainate receptor subunit 2 (GluK2) subunit-containing glutamate receptors and the following Fas ligand(FasL) up-regulation, caspase-3 activation, result in delayed apoptosis-like neuronal death in hippocampus CA1 subfield after cerebral ischemia and reperfusion. Nitric oxide-mediated S-nitrosylation might inhibit the procaspase activation, whereas denitrosylation might contribute to cleavage and activation of procaspases.
OBJECTIVE: The study aimed to elucidate the molecular mechanisms underlying procaspase-3 denitrosylation and activation following kainic acid (KA)-induced excitotoxicity in rat hippocampus.
METHODS: S-nitrosylation of procaspase-3 was detected by biotin-switch method. Activation of procaspase-3 was shown as cleavage of procaspase-3 detected by immunoblotting. FasL expression was detected by immunoblotting. Cresyl violets and TdT-mediated dUTP Nick-End Labeling (TUNEL) staining were used to detect apoptosis-like neuronal death in rat hippocampal CA1 and CA3 subfields.
RESULTS: KA led to the activation of procaspase-3 in a dose- and time-dependent manner, and the activation was inhibited by KA receptor antagonist NS102. Procaspase-3 was denitrosylated at 3 h after kainic acid administration, and the denitrosylation was reversed by SNP and GSNO. FasL ASODNs inhibited the procaspase-3 denitrosylation and activation. Moreover, thioredoxin reductase (TrxR) inhibitor auranofin prevented the denitrosylation and activation of procaspase-3 in rat hippocampal CA1 and CA3 subfields. NS102, FasL AS-ODNs, and auranofin reversed the KAinduced apoptosis and cell death in hippocampal CA1 and CA3 subfields.
CONCLUSIONS: KA led to denitrosylation and activation of procaspase-3 via FasL and TrxR. Inhibition of procaspase-3 denitrosylation by auranofin, SNP, and GSNO played protective effects against KA-induced apoptosis-like neuronal death in rat hippocampal CA1 and CA3 subfields. These investigations revealed that the procaspase-3 undergoes an initial denitrosylation process before becoming activated, providing valuable insights into the underlying mechanisms and possible treatment of excitotoxicity.

Thioredoxin reductase is an essential enzyme that plays a crucial role in maintaining cellular redox homeostasis by catalyzing the reduction of thioredoxin, which is involved in several vital cellular processes. The overexpression of TrxR is often associated with cancer development. A series of 1,2-dithiolane-4-carboxylic acid analogs were obtained to verify the selectivity of 1,2-dithiolane moiety toward TrxR. Asparagusic acid analogs and their bioisoters remain inactive toward TrxR, which proves the inability of the 1,2-dithiolane moiety to serve as a pharmacophore during the interaction with TrxR. It was found that the Michael acceptor functionality-containing analogs exhibit higher inhibitory effects against TrxR compared to other compounds of the series. The most potent representatives exhibited micromolar TrxR1 inhibition activity (IC50 varied from 5.3 to 186.0 μM) and were further examined with in vitro cell-based assays to assess the cytotoxic effects on various cancer cell lines and cell death mechanisms.

(1) Background: Tuberous sclerosis complex (TSC) mutations directly affect mTORC activity and, as a result, protein synthesis. In several cancer types, TSC mutation is part of the driver mutation panel. TSC mutations have been associated with mitochondrial dysfunction, tolerance to reactive oxygen species due to increased thioredoxin reductase (TrxR) enzyme activity, tolerance to endoplasmic reticulum (ER) stress, and apoptosis. The FDA-approved drug rapamycin is frequently used in clinical applications to inhibit protein synthesis in cancers. Recently, TrxR inhibitor auranofin has also been involved in clinical trials to investigate the anticancer efficacy of the combination treatment with rapamycin. We aimed to investigate the molecular background of the efficacy of such drug combinations in treating neoplasia modulated by TSC mutations. (2) Methods: TSC2 mutant and TSC2 wild-type (WT) cell lines were exposed to rapamycin and auranofin in either mono- or combination treatment. Mitochondrial membrane potential, TrxR enzyme activity, stress protein array, mRNA and protein levels were investigated via cell proliferation assay, electron microscopy, etc. (3) Results: Auranofin and rapamycin normalized mitochondrial membrane potential and reduced proliferation capacity of TSC2 mutant cells. Database analysis identified peroxiredoxin 5 (Prdx5) as the joint target of auranofin and rapamycin. The auranofin and the combination of the two drugs reduced Prdx5 levels. The combination treatment increased the expression of heat shock protein 70, a cellular ER stress marker. (4) Conclusions: After extensive analyses, Prdx5 was identified as a shared target of the two drugs. The decreased Prdx5 protein level and the inhibition of both TrxR and mTOR by rapamycin and auranofin in the combination treatment made ER stress-induced cell death possible in TSC2 mutant cells.

BACKGROUND: Our aim was to investigate the rationality and accuracy of plasma TrxR activity as an efficient tool in the early diagnosis of gastrointestinal malignancy, and whether TrxR can be used to evaluate the therapeutic efficacy of gastrointestinal malignancy.
METHODS: We enrolled a total of 5091 cases, including 3736 cases in gastrointestinal malignancy, 964 in benign diseases, and 391 cases in healthy controls. We also performed receiver operating characteristic (ROC) analysis to evaluate diagnostic efficiency of TrxR. Finally, we detected pre- and post-treatment level of TrxR and common tumor markers.
RESULTS: The plasma TrxR level in patients with gastrointestinal malignancy [8.4 (6.9, 9.7) U/mL] was higher than that in patients with benign disease [5.8 (4.6, 6.9) U/mL] and healthy control [3.5 (1.4, 5.4) U/mL]. Plasma TrxR showed a significant diagnostic advantage with an AUC of 0.897, compared with conventional tumor markers. In addition, the combination of TrxR and conventional tumor markers can further improve the diagnostic efficiency. We derived the optimal cut-off value of plasma TrxR as a diagnostic marker of gastrointestinal malignancy according to Youden index of 6.15 U/mL. After measuring the change trend of TrxR activity and conventional tumor markers before and after anti-tumor treatments, we found that their change trend was generally consistent, and the plasma TrxR activity was significantly decreased in patients treated with chemotherapy, targeted therapy and immunotherapy.
CONCLUSIONS: Our findings recommend that plasma TrxR activity could be monitored as an efficient tool for the early diagnosis of gastrointestinal malignancy and as a feasible tool to evaluate the therapeutic effect.