The role of thioredoxin system in cancer: strategy for cancer therapy

The emerging roles of nitric oxide in ferroptosis and pyroptosis of tumor cells

Tumor cells can develop resistance to cell death which is divided into necrosis and programmed cell death (PCD). PCD, including apoptosis, autophagy, ferroptosis, pyroptosis, and necroptosis. Ferroptosis and pyroptosis, two new forms of cell death, have gradually been of interest to researchers. Boosting ferroptosis and pyroptosis of tumor cells could be a potential cancer therapy. Nitric oxide (NO) is a ubiquitous, lipophilic, highly diffusible, free-radical signaling molecule that plays various roles in tumorigenesis. In addition, NO also has regulatory mechanisms through S-nitrosylation that do not depend on the classic NO/sGC/cGMP signaling. The current tumor treatment strategy for NO is to promote cell death through promoting S-nitrosylation-induced apoptosis while multiple drawbacks dampen this tumor therapy. However, numerous studies have suggested that suppression of NO is perceived to active ferroptosis and pyroptosis, which could be a better anti-tumor treatment. In this review, ferroptosis and pyroptosis are described in detail. We summarize that NO influences ferroptosis and pyroptosis and infer that S-nitrosylation mediates ferroptosis- and pyroptosis-related signaling pathways. It could be a potential cancer therapy different from NO-induced apoptosis of tumor cells. Finally, the information shows the drugs that manipulate endogenous production and exogenous delivery of NO to modulate the levels of S-nitrosylation.

Computational Studies of Au(I) and Au(III) Anticancer MetalLodrugs: A Survey

Owing to the growing hardware capabilities and the enhancing efficacy of computational methodologies, computational chemistry approaches have constantly become more important in the development of novel anticancer metallodrugs. Besides traditional Pt-based drugs, inorganic and organometallic complexes of other transition metals are showing increasing potential in the treatment of cancer. Among them, Au(I)- and Au(III)-based compounds are promising candidates due to the strong affinity of Au(I) cations to cysteine and selenocysteine side chains of the protein residues and to Au(III) complexes being more labile and prone to the reduction to either Au(I) or Au(0) in the physiological milieu. A correct prediction of metal complexes' properties and of their bonding interactions with potential ligands requires QM computations, usually at the ab initio or DFT level. However, MM, MD, and docking approaches can also give useful information on their binding site on large biomolecular targets, such as proteins or DNA, provided a careful parametrization of the metal force field is employed. In this review, we provide an overview of the recent computational studies of Au(I) and Au(III) antitumor compounds and of their interactions with biomolecular targets, such as sulfur- and selenium-containing enzymes, like glutathione reductases, glutathione peroxidase, glutathione-S-transferase, cysteine protease, thioredoxin reductase and poly (ADP-ribose) polymerase 1.

Personalized medicine of non-gene-specific chemotherapies for non-small cell lung cancer

Non-small cell lung cancer is recognized as the deadliest cancer across the globe. In some areas, it is more common in women than even breast and cervical cancer. Its rise, vaulted by smoking habits and increasing air pollution, has garnered much attention and resource in the medical field. The first lung cancer treatments were developed more than half a century ago. Unfortunately, many of the earlier chemotherapies often did more harm than good, especially when they were used to treat genetically unsuitable patients. With the introduction of personalized medicine, physicians are increasingly aware of when, how, and in whom, to use certain anti-cancer agents. Drugs such as tyrosine kinase inhibitors, anaplastic lymphoma kinase inhibitors, and monoclonal antibodies possess limited utility because they target specific oncogenic mutations, but other drugs that target mechanisms universal to all cancers do not. In this review, we discuss many of these non-oncogene-targeting anti-cancer agents including DNA replication inhibitors (i.e., alkylating agents and topoisomerase inhibitors) and cytoskeletal function inhibitors to highlight their application in the setting of personalized medicine as well as their limitations and resistance factors.

Auranofin and Cold Atmospheric Plasma Synergize to Trigger Distinct Cell Death Mechanisms and Immunogenic Responses in Glioblastoma

Targeting the redox balance of malignant cells via the delivery of high oxidative stress unlocks a potential therapeutic strategy against glioblastoma (GBM). We investigated a novel reactive oxygen species (ROS)-inducing combination treatment strategy, by increasing exogenous ROS via cold atmospheric plasma and inhibiting the endogenous protective antioxidant system via auranofin (AF), a thioredoxin reductase 1 (TrxR) inhibitor. The sequential combination treatment of AF and cold atmospheric plasma-treated PBS (pPBS), or AF and direct plasma application, resulted in a synergistic response in 2D and 3D GBM cell cultures, respectively. Differences in the baseline protein levels related to the antioxidant systems explained the cell-line-dependent sensitivity towards the combination treatment. The highest decrease of TrxR activity and GSH levels was observed after combination treatment of AF and pPBS when compared to AF and pPBS monotherapies. This combination also led to the highest accumulation of intracellular ROS. We confirmed a ROS-mediated response to the combination of AF and pPBS, which was able to induce distinct cell death mechanisms. On the one hand, an increase in caspase-3/7 activity, with an increase in the proportion of annexin V positive cells, indicates the induction of apoptosis in the GBM cells. On the other hand, lipid peroxidation and inhibition of cell death through an iron chelator suggest the involvement of ferroptosis in the GBM cell lines. Both cell death mechanisms induced by the combination of AF and pPBS resulted in a significant increase in danger signals (ecto-calreticulin, ATP and HMGB1) and dendritic cell maturation, indicating a potential increase in immunogenicity, although the phagocytotic capacity of dendritic cells was inhibited by AF. In vivo, sequential combination treatment of AF and cold atmospheric plasma both reduced tumor growth kinetics and prolonged survival in GBM-bearing mice. Thus, our study provides a novel therapeutic strategy for GBM to enhance the efficacy of oxidative stress-inducing therapy through a combination of AF and cold atmospheric plasma.

The effect of mitochondria-targeted antioxidant MitoQ10 on redox signaling pathway components in PCOS mouse model

PURPOSE

Considerable evidence suggests that mitochondrial dysfunction and oxidative stress contribute to the pathogenesis of Polycystic ovary syndrome (PCOS). We aimed to evaluate the effectiveness of mitochondria-targeted antioxidant, MitoQ10, on the redox signaling pathway's component in PCOS.

METHOD

We assessed TXNIP, TRX, and ASK1 expression in granulosa cells (GCs) of the DHEA-induced PCOS mouse model. Female BALB/c mice in five groups of Control, DHEA, and DHEA + MitoQ10 in three doses of 250, 500, and 750 μmol/L MitoQ10 were treated for 21 days.

RESULTS

Histological investigation showed a probable improvement in folliculogenesis; besides, ASK1 and TXNIP expression were significantly increased in GCs of the PCOS mouse F4Fmodel as compared to the control groups and decreased steadily in groups treated by MitoQ10. However, TRX expression showed a drop that was restored by MitoQ10 meaningfully (P ≤ 0.05).

CONCLUSION

The work presented herein suggests mitochondria-targeted antioxidant, MitoQ10, have modulating effects on folliculogenesis in the ovary and also on the redox signaling pathway in GCs of PCOS mouse model which may have potential to attenuate oxidative stress and its relative damages.

A Fluorine-19 Magnetic Resonance Probe, Shiga-Y5, Downregulates Thioredoxin-Interacting Protein Expression in the Brain of a Mouse Model of Alzheimer's Disease

Thioredoxin-interacting protein (TXNIP) is involved in multiple disease-associated functions related to oxidative stress, especially by inhibiting the anti-oxidant- and thiol-reducing activity of thioredoxin (TXN). Shiga-Y5 (SY5), a fluorine-19 magnetic resonance probe for detecting amyloid-β deposition in the brain, previously showed therapeutic effects in a mouse model of Alzheimer's disease; however, the mechanism of action of SY5 remains unclear. SY5 passes the blood-brain barrier and then undergoes hydrolysis to produce a derivative, Shiga-Y6 (SY6), which is a TXNIP-negative regulator. Therefore, this study investigates the therapeutic role of SY5 as the prodrug of SY6 in the thioredoxin system in the brain of a mouse model of Alzheimer's disease. The intraperitoneal injection of SY5 significantly inhibited TXNIP mRNA (p = 0.0072) and protein expression (p = 0.0143) induced in the brain of APP/PS1 mice. In contrast, the levels of TXN mRNA (p = 0.0285) and protein (p = 0.0039) in the brain of APP/PS1 mice were increased after the injection of SY5. The ratio of TXN to TXNIP, which was decreased (p = 0.0131) in the brain of APP/PS1 mice, was significantly increased (p = 0.0072) after the injection of SY5. These results suggest that SY5 acts as a prodrug of SY6 in targeting the thioredoxin system and could be a potential therapeutic compound in oxidative stress-related diseases in the brain.

Antimicrobial effect of auranofin against Acanthamoeba spp

Acanthamoebae are opportunistic pathogens that cause serious infections, including Acanthamoeba keratitis, a sight-threatening disease affecting mainly contact lens wearers, and granulomatous amoebic encephalitis, an infection of the central nervous system that occurs mostly in immunocompromised individuals. Although these infections are rare, they are a challenge for healthcare providers. In the last decade, the search for and implementation of novel treatment approaches against these parasites and the infections they cause have intensified, but current options are still unsatisfactory. The aim of this study was to investigate the in vitro activity of the gold-based compound auranofin against Acanthamoeba spp. The study showed that auranofin has potent antimicrobial activity against Acanthamoeba spp., with an IC₅₀ ranging from 2.9 to 3.48 µM, and thus may be useful in the prevention and control of Acanthamoeba infections.

Tingenone and 22-hydroxytingenone target oxidative stress through downregulation of thioredoxin, leading to DNA double-strand break and JNK/p38-mediated apoptosis in acute myeloid leukemia HL-60 cells

Acute myeloid leukemia (AML) is the most lethal form of leukemia. Standard anti-AML treatment remains almost unchanged for decades. Tingenone (TG) and 22-hydroxytingenone (22-HTG) are quinonemethide triterpenes found in the Amazonian plant Salacia impressifolia (Celastraceae), with cytotoxic properties in different histological types of cancer cells. In the present work, we investigated the anti-AML action mechanism of TG and 22-HTG in the AML HL-60 cell line. Both compounds exhibited potent cytotoxicity in a panel of cancer cell lines. Mechanistic studies found that TG and 22-HTG reduced cell growth and caused the externalization of phosphatidylserine, the fragmentation of internucleosomal DNA and the loss of mitochondrial transmembrane potential in HL-60 cells. In addition, pre-incubation with Z-VAD(OMe)-FMK, a pan-caspase inhibitor, prevented TG- and 22-HTG-induced apoptosis, indicating cell death by apoptosis via a caspase-dependent pathway. The analysis of the RNA transcripts of several genes indicated the interruption of the cellular antioxidant system, including the downregulation of thioredoxin, as a target for TG and 22-HTG. The application of N-acetyl-cysteine, an antioxidant, completely prevented apoptosis induced by TG and 22-HTG, indicating activation of the apoptosis pathway mediated by oxidative stress. Moreover, TG and 22-HTG induced DNA double-strand break and phosphorylation of JNK2 (T183/Y185) and p38α (T180/Y182), and co-incubation with SP 600125 (JNK/SAPK inhibitor) and PD 169316 (p38 MAPK inhibitor) partially prevented apoptosis induced by TG and 22-HTG. Together, these data indicate that TG and 22-HTG are new candidate for anti-AML therapy targeting thioredoxin.

Ruthenium Complexes: An Alternative to Platinum Drugs in Colorectal Cancer Treatment

Colorectal cancer (CRC) is one of the intimidating causes of death around the world. CRC originated from mutations of tumor suppressor genes, proto-oncogenes and DNA repair genes. Though platinum (Pt)-based anticancer drugs have been widely used in the treatment of cancer, their toxicity and CRC cells' resistance to Pt drugs has piqued interest in the search for alternative metal-based drugs. Ruthenium (Ru)-based compounds displayed promising anticancer activity due to their unique chemical properties. Ru-complexes are reported to exert their anticancer activities in CRC cells by regulating different cell signaling pathways that are either directly or indirectly associated with cell growth, division, proliferation, and migration. Additionally, some Ru-based drug candidates showed higher potency compared to commercially available Pt-based anticancer drugs in CRC cell line models. Meanwhile Ru nanoparticles coupled with photosensitizers or anticancer agents have also shown theranostic potential towards CRC. Ru-nanoformulations improve drug efficacy, targeted drug delivery, immune activation, and biocompatibility, and therefore may be capable of overcoming some of the existing chemotherapeutic limitations. Among the potential Ru-based compounds, only Ru (III)-based drug NKP-1339 has undergone phase-Ib clinical trials in CRC treatment.

Recent developments in selenium-containing polymeric micelles: prospective stimuli, drug-release behaviors, and intrinsic anticancer activity

Selenium is capable of forming a dynamic covalent bond with itself and other elements and can undergo metathesis and regeneration reactions under optimum conditions. Its dynamic nature endows selenium-containing polymers with striking sensitivity towards some environmental alterations. In the past decade, several selenium-containing polymers were synthesized and used for the preparation of oxidation-, reduction-, and radiation-responsive nanocarriers. Recently, thioredoxin reductase, sonication, and osmotic pressure triggered the cleavage of Se-Se bonds and swelling or disassembly of nanostructures. Moreover, some selenium-containing nanocarriers form oxidation products such as seleninic acids and acrylates with inherent anticancer activities. Thus, selenium-containing polymers hold promise for the fabrication of ultrasensitive and multifunctional nanocarriers of radiotherapeutic, chemotherapeutic, and immunotherapeutic significance. Herein, we discuss the most recent developments in selenium-containing polymeric micelles in light of their architecture, multiple stimuli-responsive properties, emerging immunomodulatory activities, and future perspectives in the delivery and controlled release of anticancer agents.

Antioxidant responses related to temozolomide resistance in glioblastoma

Glioblastoma remains one of the most challenging and devastating cancers, with only a very small proportion of patients achieving 5-year survival. The current standard of care consists of surgery, followed by radiation therapy with concurrent and maintenance chemotherapy with the alkylating agent temozolomide. To date, this drug is the only one that provides a significant survival benefit, albeit modest, as patients end up acquiring resistance to this drug. As a result, tumor progression and recurrence inevitably occur, leading to death. Several factors have been proposed to explain this resistance, including an upregulated antioxidant system to keep the elevated intracellular ROS levels, a hallmark of cancer cells, under control. In this review, we discuss the mechanisms of chemoresistance -including the important role of glioblastoma stem cells-with emphasis on antioxidant defenses and how agents that impair redox balance (i.e.: sulfasalazine, erastin, CB-839, withaferin, resveratrol, curcumin, chloroquine, and hydroxychloroquine) might be advantageous in combined therapies against this type of cancer.

Analysis of differentially expressed genes responsible for the suppressive effect of anisomycin on cell proliferation of DLD-1 cells

Anisomycin is used as a chemical compound that possesses c-Jun N-terminal kinase (JNK)-activating effects. Recently, the potent anti-tumor effects of anisomycin have received much attention. In addition to its JNK-activating effects, anisomycin has been reported to affect gene expression in osteosarcoma, leukemia, hepatocellular carcinoma, ovarian cancer and other cancers. We previously demonstrated that anisomycin induced the degradation of transcription factor GATA-6 in DLD-1 cells (a colorectal cancer cell line) and inhibited their proliferation. However, the details of the gene network involved in the process remain unclear. In this study, we conducted an RNA-seq analysis of differentially expressed genes (DEGs) in anisomycin-treated DLD-1 cells to identify the molecular process of growth-suppressive genes. We found that LAMB3, which regulates cell adhesion and migration, and NFKB2 were down-regulated by anisomycin. In addition, the mRNA expression of several tumor suppressor genes (ATF3, ERRFI1, KLF6, and AKAP12) was transiently enhanced at 3 h after anisomycin treatment. These results suggest that anisomycin blocks a PI3K/Akt-signaling cascade to lead to the suppression of cell growth.

Stable duplex-linked antisense targeting miR-148a inhibits breast cancer cell proliferation

MicroRNAs (miRNAs) regulate cancer cell proliferation by binding directly to the untranslated regions of messenger RNA (mRNA). MicroRNA-148a (miR-148a) is expressed at low levels in breast cancer (BC). However, little attention has been paid to the sequestration of miR-148a. Here, we performed a knockdown of miR-148a using anti-miRNA oligonucleotides (AMOs) and investigated the effect on BC cell proliferation. BC cell proliferation was significantly suppressed by AMO flanked by interstrand cross-linked duplexes (CL-AMO), whereas single-stranded and commercially available AMOs had no effect. The suppression was caused by sequestering specifically miR-148a. Indeed, miR-148b, another member of the miR-148 family, was not affected. Importantly, the downregulation of miR-148a induced a greater and longer-lasting inhibition of BC cell proliferation than the targeting of oncogenic microRNA-21 (miR-21) did. We identified thioredoxin-interacting protein (TXNIP), a tumor suppressor gene, as a target of miR-148a and showed that CL-AMO provoked an increase in TXNIP mRNA expression. This study provide evidence that lowly expressed miRNAs such as miR-148a have an oncogenic function and might be a promising target for cancer treatment.

Selenium as a Bioactive Micronutrient in the Human Diet and Its Cancer Chemopreventive Activity

This review answers the question of why selenium is such an important trace element in the human diet. Daily dietary intake of selenium and its content in various food products is discussed in this paper, as well as the effects of its deficiency and excess in the body. Moreover, the biological activity of selenium, which it performs mainly through selenoproteins, is discussed. These specific proteins are responsible for thyroid hormone management, fertility, the aging process, and immunity, but their key role is to maintain a redox balance in cells. Furthermore, taking into account world news and the current SARS-CoV-2 virus pandemic, the impact of selenium on the course of COVID-19 is also discussed. Another worldwide problem is the number of new cancer cases and cancer-related mortality. Thus, the last part of the article discusses the impact of selenium on cancer risk based on clinical trials (including NPC and SELECT), systematic reviews, and meta-analyses. Additionally, this review discusses the possible mechanisms of selenium action that prevent cancer development.

Rollover Cyclometalation vs Nitrogen Coordination in Tetrapyridyl Anticancer Gold(III) Complexes: Effect on Protein Interaction and Toxicity

In this work, a pair of gold(III) complexes derived from the analogous tetrapyridyl ligands H₂biqbpy1 and H₂biqbpy2 was prepared: the rollover, bis-cyclometalated [Au(biqbpy1)Cl ([1]Cl) and its isomer [Au(biqbpy2)Cl ([2]Cl). In [1]⁺, two pyridyl rings coordinate to the metal via a Au-C bond (C^∧N^∧N^∧C coordination) and the two noncoordinated amine bridges of the ligand remain protonated, while in [2]⁺ all four pyridyl rings of the ligand coordinate to the metal via a Au-N bond (N^∧N^∧N^∧N coordination), but both amine bridges are deprotonated. As a result, both complexes are monocationic, which allowed comparison of the sole effect of cyclometalation on the chemistry, protein interaction, and anticancer properties of the gold(III) compounds. Due to their identical monocationic charge and similar molecular shape, both complexes [1]Cl and [2]Cl displaced reference radioligand [³H]dofetilide equally well from cell membranes expressing the K_v11.1 (hERG) potassium channel, and more so than the tetrapyridyl ligands H₂biqbpy1 and H₂biqbpy2. By contrast, cyclometalation rendered [1]Cl coordinatively stable in the presence of biological thiols, while [2]Cl was reduced by a millimolar concentration of glutathione into metastable Au(I) species releasing the free ligand H₂biqbpy2 and TrxR-inhibiting Au⁺ ions. The redox stability of [1]Cl dramatically decreased its thioredoxin reductase (TrxR) inhibition properties, compared to [2]Cl. On the other hand, unlike [2]Cl, [1]Cl aggregated into nanoparticles in FCS-containing medium, which resulted in much more efficient gold cellular uptake. [1]Cl had much more selective anticancer properties than [2]Cl and cisplatin, as it was almost 10 times more cytotoxic to human cancer cells (A549, A431, A375, and MCF7) than to noncancerous cells (MRC5). Mechanistic studies highlight the strikingly different mode of action of the two compounds: while for [1]Cl high gold cellular uptake, nuclear DNA damage, and interaction with hERG may contribute to cell killing, for [2]Cl extracellular reduction released TrxR-inhibiting Au⁺ ions that were taken up in minute amounts in the cytosol, and a toxic tetrapyridyl ligand also capable of binding to hERG. These results demonstrate that bis-cyclometalation is an appealing method to improve the redox stability of Au(III) compounds and to develop gold-based cytotoxic compounds that do not rely on TrxR inhibition to kill cancer cells.

Chemopreventive and Anticancer Property of Selenoproteins in Obese Breast Cancer

Obesity is a significant risk factor for various cancers including breast cancer resulting in an increased risk of recurrence as well as morbidity and mortality. Extensive studies on various pathways have been successful in establishing a biological relationship between obesity and breast cancer. The molecular classification of breast cancer includes five groups each having different responses to treatment. Increased levels of inflammatory cytokines seen in obese conditions drive the pro-proliferative pathways, such as the influx of macrophages, angiogenesis, and antiapoptotic pathways. Increased peripheral aromatization of androgens by aromatase increases the circulating estrogen levels which are also responsible for the association of obesity with breast cancer. Also, increased oxidative stress due to chronic low-grade inflammation in obese women plays an important role in carcinogenesis. Despite the availability of safe and effective treatment options for breast cancer, obese women are at increased risk of adverse outcomes including treatment-related toxicities. In the recent decade, selenium compounds have gained substantial interest as chemopreventive and anticancer agents. The chemical derivatives of selenium include inorganic and organic compounds that exhibit pro-oxidant properties and alter cellular redox homeostasis. They target more than one metabolic pathway by thiol modifications, induction of reactive oxygen species, and chromatin modifications to exert their chemopreventive and anticancer activities. The primary functional effectors of selenium that play a significant role in human homeostasis are selenoproteins like glutathione peroxidase, thioredoxin reductase, iodothyronine deiodinases, and selenoprotein P. Selenoproteins play a significant role in adipose tissue physiology by modulating preadipocyte proliferation and adipogenic differentiation. They correlate negatively with body mass index resulting in increased oxidative stress that may lead to carcinogenesis in obese individuals. Methylseleninic acid effectively suppresses aromatase activation thus reducing the estrogen levels and acting as a breast cancer chemopreventive agent. Adipose-derived inflammatory mediators influence the selenium metabolites and affect the proliferation and metastatic properties of cancer cells. Recently selenium nanoparticles have shown potent anticancer activity which may lead to a major breakthrough in the management of cancers caused due to multiple pathways. In this review, we discuss the possible role of selenoproteins as chemopreventive and an anticancer agent in obese breast cancer.

Pharmaceutical Drug Metformin and MCL1 Inhibitor S63845 Exhibit Anticancer Activity in Myeloid Leukemia Cells via Redox Remodeling

Metabolic landscape and sensitivity to apoptosis induction play a crucial role in acute myeloid leukemia (AML) resistance. Therefore, we investigated the effect of metformin, a medication that also acts as an inhibitor of oxidative phosphorylation (OXPHOS), and MCL-1 inhibitor S63845 in AML cell lines NB4, KG1 and chemoresistant KG1A cells. The impact of compounds was evaluated using fluorescence-based metabolic flux analysis, assessment of mitochondrial Δψ and cellular ROS, trypan blue exclusion, Annexin V-PI and XTT tests for cell death and cytotoxicity estimations, also RT-qPCR and Western blot for gene and protein expression. Treatment with metformin resulted in significant downregulation of OXPHOS; however, increase in glycolysis was observed in NB4 and KG1A cells. In contrast, treatment with S63845 slightly increased the rate of OXPHOS in KG1 and KG1A cells, although it profoundly diminished the rate of glycolysis. Generally, combined treatment had stronger inhibitory effects on cellular metabolism and ATP levels. Furthermore, results revealed that treatment with metformin, S63845 and their combinations induced apoptosis in AML cells. In addition, level of apoptotic cell death correlated with cellular ROS induction, as well as with downregulation of tumor suppressor protein MYC. In summary, we show that modulation of redox-stress could have a potential anticancer activity in AML cells.

Low expression of the PPARγ-regulated gene thioredoxin-interacting protein accompanies human melanoma progression and promotes experimental lung metastases

The thioredoxin system plays key roles in regulating cancer cell malignancy. Here we identify the Thioredoxin-interacting protein (TXNIP) as a gene, which expression is regulated by PPARγ in melanoma cells. We show that high TXNIP expression levels associate with benign melanocytic lesions, with tumor regression in patients on MAP kinase targeted therapy, with decreased proliferation in patients’ melanoma biopsies, and with cell cycle arrest in human melanoma cell lines. In contrast, reduced TXNIP expression associates with advanced melanoma and with disease progression in patients. TXNIP depletion in human melanoma cells altered the expression of integrin beta-3 and the localization of the integrin alpha-v/beta-3 dimer at their surface. Moreover, TXNIP depletion affected human melanoma cell motility and improved their capacity to colonize mouse lungs in an in vivo assay. This study establishes TXNIP as a PPARγ-regulated gene in melanoma cells, thereby suggesting a link between these two proteins both involved in the regulation of cancer and of energy metabolism. It also reveals that the decrease in TXNIP expression, which is observed in advanced patient tumors, likely favors lung metastatic seeding of malignant cells.

A "Golden Age" for the discovery of new antileishmanial agents: Current status of leishmanicidal gold complexes and prospective targets beyond the trypanothione system

Leishmaniasis is one of the most neglected diseases worldwide and is considered a serious public health issue. The current therapeutic options have several disadvantages that make the search for new therapeutics urgent. Gold compounds are emerging as promising candidates based on encouraging in vitro and limited in vivo results for several Au^I and Au^III complexes. The antiparasitic mechanisms of these molecules remain only partially understood. However, a few studies have proposed the trypanothione redox system as a target, similar to the mammalian thioredoxin system, pointed out as the main target for several gold compounds with significant antitumor activity. In this review, we present the current status of the investigation and design of gold compounds directed at treating leishmaniasis. In addition, we explore potential targets in Leishmania parasites beyond the trypanothione system, taking into account previous studies and structure modulation performed for gold-based compounds.

Synthesis and biological evaluation of disulfides as anticancer agents with thioredoxin inhibition

Altered redox homeostasis as a hallmark of cancer cells is exploited by cancer cells for growth and survival. The thioredoxin (Trx), an important regulator in maintaining the intracellular redox homeostasis, is cumulatively recognized as a promising target for the development of anticancer drugs. Herein, we synthesized 72 disulfides and evaluated theirinhibition for Trx and antitumor activity. First, we established an efficient and fast method to screen Trx inhibitors by using the probe NBL-SS that was developed by our group to detect Trx function in living cells. After an initial screening of the Trx inhibitory activity of these compounds, 8 compounds showed significant inhibition activity against Trx. We then evaluated the cytotoxicity of these 8 disulfides, compounds 68 and 69 displayed high cytotoxicity to HeLa cells, but less sensitive to normal cell lines. Next, we performed kinetic studies of both two disulfides, 68 had faster inhibition of Trx than 69. Further studies revealed that 68 led to the accumulation of reactive oxygen species and eventually induced apoptosis of Hela cells via inhibiting Trx. The establishment of a method for screening Trx inhibitors and the discovery of 68 with remarkable Trx inhibition provide support for the development of anticancer candidates with Trx inhibition.

Role of Thioredoxin-Interacting Protein in Diseases and Its Therapeutic Outlook

Thioredoxin-interacting protein (TXNIP), widely known as thioredoxin-binding protein 2 (TBP2), is a major binding mediator in the thioredoxin (TXN) antioxidant system, which involves a reduction-oxidation (redox) signaling complex and is pivotal for the pathophysiology of some diseases. TXNIP increases reactive oxygen species production and oxidative stress and thereby contributes to apoptosis. Recent studies indicate an evolving role of TXNIP in the pathogenesis of complex diseases such as metabolic disorders, neurological disorders, and inflammatory illnesses. In addition, TXNIP has gained significant attention due to its wide range of functions in energy metabolism, insulin sensitivity, improved insulin secretion, and also in the regulation of glucose and tumor suppressor activities in various cancers. This review aims to highlight the roles of TXNIP in the field of diabetology, neurodegenerative diseases, and inflammation. TXNIP is found to be a promising novel therapeutic target in the current review, not only in the aforementioned diseases but also in prolonged microvascular and macrovascular diseases. Therefore, TXNIP inhibitors hold promise for preventing the growing incidence of complications in relevant diseases.

The role of TXNL1 in disease: treatment strategies for cancer and diseases with oxidative stress

Thioredoxin-like protein-1 (TXNL1; also known as thioredoxin-related 32 kDa protein, TRP32) is a thioredoxin involved in the regulation of oxidative stress, which protects cells from damage through redox balance. Studies have shown that TXNL1 has a variety of functions, including cell signal transduction, cell cycle regulation, protein synthesis, modification and degradation, vesicle transport, transcriptional regulation, cell apoptosis, virus replication and oxidative stress regulation, etc., and plays an important role in the occurrence and development of human diseases. Therefore, TXNL1 has a strong correlation with the treatment of cancer and oxidative stress diseases. In this paper, the basic structure, function and potential application value of TXNL1 in diseases are reviewed, so as to open up new targets for the treatment of cancer and oxidative stress-related diseases.

Investigating the Thioredoxin and Glutathione Systems' Response in Lymphoma Cells after Treatment with [Au(d2pype)2]CL

Lymphoma is a blood cancer comprising various subtypes. Although effective therapies are available, some patients fail to respond to treatment and can suffer from side effects. Antioxidant systems, especially the thioredoxin (Trx) and glutathione (GSH) systems, are known to enhance cancer cell survival, with thioredoxin reductase (TrxR) recently reported as a potential anticancer target. Since the GSH system can compensate for some Trx system functions, we investigated its response in three lymphoma cell lines after inhibiting TrxR activity with [Au(d2pype)2]Cl, a known TrxR inhibitor. [Au(d2pype)2]Cl increased intracellular reactive oxygen species (ROS) levels and induced caspase-3 activity leading to cell apoptosis through inhibiting both TrxR and glutathione peroxidase (Gpx) activity. Expression of the tumour suppresser gene TXNIP increased, while GPX1 and GPX4 expression, which are related to poor prognosis of lymphoma patients, decreased. Unlike SUDHL2 and SUDHL4 cells, which exhibited a decreased GSH/GSSG ratio after treatment, in KMH2 cells the ratio remained unchanged, while glutathione reductase and glutaredoxin expression increased. Since KMH2 cells were less sensitive to treatment with [Au(d2pype)2]Cl, the GSH system may play a role in protecting cells from apoptosis after TrxR inhibition. Overall, our study demonstrates that inhibition of TrxR represents a valid therapeutic approach for lymphoma.

Impact of the acidic environment on gene expression and functional parameters of tumors in vitro and in vivo

Background

The low extracellular pH (pH_e) of tumors resulting from glycolytic metabolism is a stress factor for the cells independent from concomitant hypoxia. The aim of the study was to analyze the impact of acidic pH_e on gene expression on mRNA and protein level in two experimental tumor lines in vitro and in vivo and were compared to hypoxic conditions as well as combined acidosis+hypoxia.

Methods

Gene expression was analyzed in AT1 prostate and Walker-256 mammary carcinoma of the rat by Next Generation Sequencing (NGS), qPCR and Western blot. In addition, the impact of acidosis on tumor cell migration, adhesion, proliferation, cell death and mitochondrial activity was analyzed.

Results

NGS analyses revealed that 147 genes were uniformly regulated in both cell lines (in vitro) and 79 genes in both experimental tumors after 24 h at low pH. A subset of 25 genes was re-evaluated by qPCR and Western blot. Low pH consistently upregulated Aox1, Gls2, Gstp1, Ikbke, Per3, Pink1, Tlr5, Txnip, Ypel3 or downregulated Acat2, Brip1, Clspn, Dnajc25, Ercc6l, Mmd, Rif1, Zmpste24 whereas hypoxia alone led to a downregulation of most of the genes. Direct incubation at low pH reduced tumor cell adhesion whereas acidic pre-incubation increased the adhesive potential. In both tumor lines acidosis induced a G1-arrest (in vivo) of the cell cycle and a strong increase in necrotic cell death (but not in apoptosis). The mitochondrial O₂ consumption increased gradually with decreasing pH.

Conclusions

These data show that acidic pH_e in tumors plays an important role for gene expression independently from hypoxia. In parallel, acidosis modulates functional properties of tumors relevant for their malignant potential and which might be the result of pH-dependent gene expression.

Preventing Colitis-Associated Colon Cancer With Antioxidants: A Systematic Review

Inflammatory bowel disease (IBD) patients have an increased risk of developing colitis-associated colon cancer (CAC); however, the basis for inflammation-induced genetic damage requisite for neoplasia is unclear. Several studies have shown that IBD patients have signs of increased oxidative damage, which could be a result of genetic and environmental factors such as an excess in oxidant molecules released during chronic inflammation, mitochondrial dysfunction, a failure in antioxidant capacity, or oxidant promoting diets. It has been suggested that chronic oxidative environment in the intestine leads to the DNA lesions that precipitate colon carcinogenesis in IBD patients. Indeed, several preclinical and clinical studies show that different endogenous and exogenous antioxidant molecules are effective at reducing oxidation in the intestine. However, most clinical studies have focused on the short-term effects of antioxidants in IBD patients but not in CAC. This review article examines the role of oxidative DNA damage as a possible precipitating event in CAC in the context of chronic intestinal inflammation and the potential role of exogenous antioxidants to prevent these cancers.

Cryopreservation and oxidative stress in porcine oocytes

Several vitrification protocols have been established for porcine oocytes so as to facilitate gene banking of female germplasm. Although live piglets have been successfully produced from pig oocytes vitrified at the germinal vesicle (GV) stage, the competence of vitrified oocytes to develop into the blastocyst stage is greatly compromised following cryopreservation. The focus of this review is to elucidate the impact of cryopreservation on the redox balance of pig oocytes, making special reference to the relevance of non-enzymatic and enzymatic antioxidant defences. Besides, the regulation of gene expression in response to oxidative stress is also considered. Finally, we discuss the effects of supplementing maturation and vitrification media with the exogenous non-enzymatic antioxidants that have hitherto yielded the most relevant results.

The Potential Roles of Redox Enzymes in Alzheimer's Disease: Focus on Thioredoxin

Alzheimer's disease (AD) is the most common neurodegenerative diseases. Increasing studies have demonstrated the critical importance for redox proteins mediating neuronal protection in models of AD. This review briefly describes some of the risk factors contributing to AD, specifically highlighting the important roles of oxidative stress in the pathology of AD. Then this article concisely introduces the dysregulation and functions of two main redox enzymes, peroxiredoxins and glutaredoxins, in AD models. This review emphasizes the neuroprotective role of the third redox enzyme thioredoxin (Trx), an important multifunctional protein regulating cellular redox status. This commentary not only summarizes the alterations of Trx expression in AD patients and models, but also reviews the potential effects and mechanisms of Trx, Trx-related molecules and Trx-inducing compounds against AD. In conclusion, Trx has a potential neuroprotection in AD and may be very promising for clinical therapy of AD in the future.

Amikacin Suppresses Human Breast Cancer Cell MDA-MB-231 Migration and Invasion

(1) Background: Amikacin is an aminoglycoside antibiotic used for treating gram-negative bacterial infections in cancer patients. In this study, our aims are to investigate the migratory inhibition effects of amikacin in human MDA-MB-231 cells. (2) Methods: We used a wound-healing assay, trans-well analysis, Western blotting, immunostaining and siRNA knockdown approaches to investigate how amikacin influenced MDA-MB-231 cell migration and invasion. (3) Results: Wound healing showed that the MDA-MB-231 cell migration rates decreased to 44.4% in the presence of amikacin. Trans-well analysis showed that amikacin treatment led to invasion inhibition. Western blotting demonstrated that amikacin induced thioredoxin-interacting protein (TXNIP) up-regulation. TXNIP was knocked down using siRNA in MDA-MB-231 cell. Using immunostaining analysis, we found that inhibition of TXNIP expression led to MDA-MB-231 pseudopodia extension; however, amikacin treatment attenuated the cell extension formation. (4) Conclusions: We observed inhibition of migration and invasion in MDA-MB-231 cells treated with amikacin. This suggests inhibition might be mediated by up-regulation of TXNIP.

The multifaceted roles of sulfane sulfur species in cancer-associated processes

Sulfane sulfur species comprise a variety of biologically relevant hydrogen sulfide (H₂S)-derived species, including per- and poly-sulfidated low molecular weight compounds and proteins. A growing body of evidence suggests that H₂S, currently recognized as a key signaling molecule in human physiology and pathophysiology, plays an important role in cancer biology by modulating cell bioenergetics and contributing to metabolic reprogramming. This is accomplished through functional modulation of target proteins via H₂S binding to heme iron centers or H₂S-mediated reversible per- or poly-sulfidation of specific cysteine residues. Since sulfane sulfur species are increasingly viewed not only as a major source of H₂S but also as key mediators of some of the biological effects commonly attributed to H₂S, the multifaceted role of these species in cancer biology is reviewed here with reference to H₂S, focusing on their metabolism, signaling function, impact on cell bioenergetics and anti-tumoral properties.

A New Twist in Protein Kinase B/Akt Signaling: Role of Altered Cancer Cell Metabolism in Akt-Mediated Therapy Resistance

Cancer resistance to chemotherapy, radiotherapy and molecular-targeted agents is a major obstacle to successful cancer therapy. Herein, aberrant activation of the phosphatidyl-inositol-3-kinase (PI3K)/protein kinase B (Akt) pathway is one of the most frequently deregulated pathways in cancer cells and has been associated with multiple aspects of therapy resistance. These include, for example, survival under stress conditions, apoptosis resistance, activation of the cellular response to DNA damage and repair of radiation-induced or chemotherapy-induced DNA damage, particularly DNA double strand breaks (DSB). One further important, yet not much investigated aspect of Akt-dependent signaling is the regulation of cell metabolism. In fact, many Akt target proteins are part of or involved in the regulation of metabolic pathways. Furthermore, recent studies revealed the importance of certain metabolites for protection against therapy-induced cell stress and the repair of therapy-induced DNA damage. Thus far, the likely interaction between deregulated activation of Akt, altered cancer metabolism and therapy resistance is not yet well understood. The present review describes the documented interactions between Akt, its target proteins and cancer cell metabolism, focusing on antioxidant defense and DSB repair. Furthermore, the review highlights potential connections between deregulated Akt, cancer cell metabolism and therapy resistance of cancer cells through altered DSB repair and discusses potential resulting therapeutic implications.

Thioredoxin Interacting Protein (TXNIP) Is Differentially Expressed in Human Tumor Samples but Is Absent in Human Tumor Cell Line Xenografts: Implications for Its Use as an Immunosurveillance Marker

Simple Summary

The metabolic protein TXNIP plays a crucial role in various cellular processes. Abnormal TXNIP levels are notable, e.g., in type II diabetes, cardiovascular diseases, and tumors. Using immunohistochemical staining for TXNIP in different tumor entities, we give new insights of TXNIP expression on the protein level. In human tumors, staining intensity inversely correlated with aggressiveness of the tumor entity. In contrast, human tumor cell lines grown in mice (xenografts), consistently revealed no staining. Hence, loss of TXNIP suggests a critical role for the development of tumors in xenografts. Furthermore, we investigated TXNIP staining of immunocompetent cells in the proximity of the xenograft tumor tissue. Our findings demonstrate that TXNIP downregulation is a common feature in human tumor xenograft models. Subsequently, TXNIP expression might be used to monitor the functional state of tumor-infiltrating leukocytes in tissue sections and may help to predict response to modern immune therapy.

Abstract

Thioredoxin interacting protein (TXNIP) is a metabolic protein critically involved in redox homeostasis and has been proposed as a tumor suppressor gene in a variety of malignancies. Accordingly, TXNIP is downregulated in breast, bladder, and gastric cancer and in tumor transplant models TXNIP overexpression inhibits growth and metastasis. As TXNIP protein expression has only been investigated in few malignancies, we employed immunohistochemical detection in a large multi-tumor tissue microarray consisting of 2,824 samples from 94 different tumor entities. In general, TXNIP protein was present only in a small proportion of primary tumor samples and in these cases was differently expressed depending on tumor stage and subtype (e.g., renal cell carcinoma, thyroid cancer, breast cancer, and ductal pancreatic cancer). Further, TXNIP protein expression was determined in primary mouse xenograft tumors derived from human cancer cell lines and was immunohistochemically absent in all xenograft tumors investigated. Intriguingly, TXNIP expression became gradually lower in the proximity of the primary tumor tissue and was absent in leukocytes directly adjacent to tumor tissue. In conclusion, these findings suggest that TXNIP downregulation is as a common feature in human tumor xenograft models and that intra-tumoral leukocytes down-regulate TXNIP. Hence TXNIP expression might be used to monitor the functional state of tumor-infiltrating leukocytes in tissue sections.

Redox Status and Antioxidative Cofactor Metals Influence Clinical and Pathological Characteristics of Papillary Thyroid Carcinoma and Colloid Goiter

Papillary thyroid carcinoma (PTC) is the endocrine neoplasm that occurs the most often worldwide, and its molecular pathophysiology is still not well characterized. Redox status is recognized as an important factor of carcinogenesis, but its influence on the PTC's clinical course needs to be better elucidated. The aim of this research was to determine the tissue redox status of 65 PTC and 45 colloid goiter (CG) patients together with antioxidative cofactor metal profiling. The malondialdehyde (MDA) concentration was used to access the prooxidation level, while antioxidant mechanisms were estimated by assaying the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR). The antioxidative cofactor metals included quantification of Se, Cu, Zn, and Mn concentration. PTC tissues had normal prooxidation levels and increased GPx and GR activity. The activity of SOD has been significantly reduced in multicentric PTC dissemination and increased in smokers. SOD activity was directly dependent on MDA levels in CG tissues. CG patients with retrosternal goiter had reduced MDA concentration and SOD activity. Numerous correlations between redox parameters in PTC tissues reveal good co-activation of antioxidative mechanisms and cooperative response on prooxidation. PTC tissues had decreased Se levels and increased concentration of Cu and Mn in comparison to other tissues. MDA concentration and SOD activity were significant predictors of PTC's multicentric dissemination and for the existence of lymph node metastases, respectively. Particularly, the concentration of Cu predicted the retrosternal localization in CG patients. Significant findings presented in this study provide a possibility for development of novel prognostic molecular biomarkers of PTC and CG.

Auranofin Enhances Sulforaphane-Mediated Apoptosis in Hepatocellular Carcinoma Hep3B Cells through Inactivation of the PI3K/Akt Signaling Pathway

The thioredoxin (Trx) system plays critical roles in regulating intracellular redox levels and defending organisms against oxidative stress. Recent studies indicated that Trx reductase (TrxR) was overexpressed in various types of human cancer cells indicating that the Trx-TrxR system may be a potential target for anti-cancer drug development. This study investigated the synergistic effect of auranofin, a TrxR-specific inhibitor, on sulforaphane-mediated apoptotic cell death using Hep3B cells. The results showed that sulforaphane significantly enhanced auranofin-induced apoptosis by inhibiting TrxR activity and cell proliferation compared to either single treatment. The synergistic effect of sulforaphane and auranofin on apoptosis was evidenced by an increased annexin-V-positive cells and Sub-G1 cells. The induction of apoptosis by the combined treatment caused the loss of mitochondrial membrane potential (ΔΨm) and upregulation of Bax. In addition, the proteolytic activities of caspases (-3, -8, and -9) and the degradation of poly (ADP-ribose) polymerase, a substrate protein of activated caspase-3, were also higher in the combined treatment. Moreover, combined treatment induced excessive generation of reactive oxygen species (ROS). However, treatment with N-acetyl-L-cysteine, a ROS scavenger, reduced combined treatment-induced ROS production and apoptosis. Thereby, these results deduce that ROS played a pivotal role in apoptosis induced by auranofin and sulforaphane. Furthermore, apoptosis induced by auranofin and sulforaphane was significantly increased through inhibition of the phosphoinositide 3-kinase (PI3K)/Akt pathway. Taken together, the present study demonstrated that down-regulation of TrxR activity contributed to the synergistic effect of auranofin and sulforaphane on apoptosis through ROS production and inhibition of PI3K/Akt signaling pathway.

The Thioredoxin-Interacting Protein TXNIP Is a Putative Tumour Suppressor in Cutaneous T-Cell Lymphoma

BACKGROUND

The thioredoxin-interacting protein (TXNIP) is involved in cellular metabolism and cell proliferation, and recently, deficient expression of TXNIP has been associated with progression and poor outcome for cancer patients.

OBJECTIVES

To assess TXNIP expression and function in malignant T cells from cutaneous T-cell lymphoma (CTCL).

METHODS

CTCL-derived malignant (MyLa2059, PB2B) and non-malignant (MyLa1850) cell lines were analysed by Western blotting and qPCR for TXNIP expression. Subsequently, the malignant CTCL cell lines were treated with GSK126 - an inhibitor of enhancer of zeste homolog 2 (EZH2) methyltransferase activity or assessed by bisulphite sequencing for TXNIP promoter methylation. Methylation was also assessed with the demethylating agent 5-azacytidine (5AZA). Finally, TXNIP was overexpressed in the malignant PB2B cell line via plasmid transduction, and the effect of TXNIP was further analysed by flow cytometry.

RESULTS

We report on low expression of TXNIP protein in all cell lines representing different subtypes and stages of CTCL when compared to non-malignant T cells. Epigenetic silencing and other mechanisms were involved in the repression of TXNIP whereas forced expression of TXNIP strongly inhibited proliferation of malignant T cells.

CONCLUSIONS

Epigenetic silencing and other as yet unknown mechanisms repress TXNIP expression in malignant T cells. As forced expression of TXNIP inhibits malignant proliferation, we propose that TXNIP is a putative tumour suppressor in CTCL.

Oxidative Stress in Cancer

Contingent upon concentration, reactive oxygen species (ROS) influence cancer evolution in apparently contradictory ways, either initiating/stimulating tumorigenesis and supporting transformation/proliferation of cancer cells or causing cell death. To accommodate high ROS levels, tumor cells modify sulfur-based metabolism, NADPH generation, and the activity of antioxidant transcription factors. During initiation, genetic changes enable cell survival under high ROS levels by activating antioxidant transcription factors or increasing NADPH via the pentose phosphate pathway (PPP). During progression and metastasis, tumor cells adapt to oxidative stress by increasing NADPH in various ways, including activation of AMPK, the PPP, and reductive glutamine and folate metabolism.

Cancer Cell Acid Adaptation Gene Expression Response Is Correlated to Tumor-Specific Tissue Expression Profiles and Patient Survival

The acidic pH of the tumor microenvironment plays a critical role in driving cancer development toward a more aggressive phenotype, but the underlying mechanisms are unclear. To this end, phenotypic and genotypic changes induced by adaptation of cancer cells to chronic acidosis have been studied. However, the generality of acid adaptation patterns across cell models and their correlation to the molecular phenotypes and aggressiveness of human cancers are essentially unknown. Here, we define an acid adaptation expression response shared across three cancer cell models, dominated by metabolic rewiring, extracellular matrix remodeling, and altered cell cycle regulation and DNA damage response. We find that many genes which are upregulated by acid adaptation are significantly correlated to patient survival, and more generally, that there are clear correlations between acid adaptation expression response and gene expression change between normal and tumor tissues, for a large subset of cancer patients. Our data support the notion that tumor microenvironment acidity is one of the key factors driving the selection of aggressive cancer cells in human patient tumors, yet it also induces a growth-limiting genotype that likely limits cancer cell growth until the cells are released from acidosis, for instance during invasion.

ROS-Mediated Therapeutic Strategy in Chemo-/Radiotherapy of Head and Neck Cancer

Head and neck cancer is a highly genetic and metabolic heterogeneous collection of malignancies of the lip, oral cavity, salivary glands, pharynx, esophagus, paranasal sinuses, and larynx with five-year survival rates ranging from 12% to 93%. Patients with head and neck cancer typically present with advanced stage III, IVa, or IVb disease and are treated with comprehensive modality including chemotherapy, radiotherapy, and surgery. Despite advancements in treatment modality and technique, noisome recurrence, invasiveness, and resistance as well as posttreatment complications severely influence survival rate and quality of life. Thus, new therapeutic strategies are urgently needed that offer enhanced efficacy with less toxicity. ROS in cancer cells plays a vital role in regulating cell death, DNA repair, stemness maintenance, metabolic reprogramming, and tumor microenvironment, all of which have been implicated in resistance to chemo-/radiotherapy of head and neck cancer. Adjusting ROS generation and elimination to reverse the resistance of cancer cells without impairing normal cells show great hope in improving the therapeutic efficacy of chemo-/radiotherapy of head and neck cancer. In the current review, we discuss the pivotal and targetable redox-regulating system including superoxide dismutases (SODs), tripeptide glutathione (GSH), thioredoxin (Trxs), peroxiredoxins (PRXs), nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/keap1), and mitochondria electron transporter chain (ETC) complexes and their roles in regulating ROS levels and their clinical significance implicated in chemo-/radiotherapy of head and neck cancer. We also summarize several old drugs (referred to as the non-anti-cancer drugs used in other diseases for a long time) and small molecular compounds as well as natural herbs which effectively modulate cellular ROS of head and neck cancer to synergize the efficacy of conventional chemo-/radiotherapy. Emerging interdisciplinary techniques including photodynamic, nanoparticle system, and Bio-Electro-Magnetic-Energy-Regulation (BEMER) therapy are promising measures to broaden the potency of ROS modulation for the benefit of chemo-/radiotherapy in head and neck cancer.

Licochalcone a Induces ROS-Mediated Apoptosis through TrxR1 Inactivation in Colorectal Cancer Cells

Licochalcone A (LCA) exhibited anticancer activity through modulating reactive oxygen species (ROS) levels in some cancer cells and has been evidenced to suppress colorectal cancer (CRC) formation and progression. However, whether LCA mediates the progression of CRC by regulating ROS production remains unclear. To address this, HCT-116 cells were treated with LCA, resulting in G0/G1 phase arrest, apoptosis, and high ROS generation, which were attenuated by N-acetyl-L-cysteine, a ROS inhibitor. In addition, LCA suppressed the expression of thioredoxin reductase 1 (TrxR1) in HCT-116 cells, leading to high ROS levels and apoptosis. Moreover, LCA administration combined with TrxR1 inhibition further enhanced the production of ROS and apoptosis in HCT-116 cells compared to LCA administration or TrxR1 inhibition alone. These results demonstrated that LCA might enhance the production of ROS by targeting TrxR1, leading to apoptosis in HCT-116 cells, which provides potential insight for the interventional treatment of CRC.

Targeting the Redox Landscape in Cancer Therapy

Reactive oxygen species (ROS) are produced predominantly by the mitochondrial electron transport chain and by NADPH oxidases in peroxisomes and in the endoplasmic reticulum. The antioxidative defense counters overproduction of ROS with detoxifying enzymes and molecular scavengers, for instance, superoxide dismutase and glutathione, in order to restore redox homeostasis. Mutations in the redox landscape can induce carcinogenesis, whereas increased ROS production can perpetuate cancer development. Moreover, cancer cells can increase production of antioxidants, leading to resistance against chemo- or radiotherapy. Research has been developing pharmaceuticals to target the redox landscape in cancer. For instance, inhibition of key players in the redox landscape aims to modulate ROS production in order to prevent tumor development or to sensitize cancer cells in radiotherapy. Besides the redox landscape of a single cell, alternative strategies take aim at the multi-cellular level. Extracellular vesicles, such as exosomes, are crucial for the development of the hypoxic tumor microenvironment, and hence are explored as target and as drug delivery systems in cancer therapy. This review summarizes the current pharmaceutical and experimental interventions of the cancer redox landscape.

AMPK α1 Downregulates ROS Levels Through Regulating Trx Leading to Dysfunction of Apoptosis in Non-Small Cell Lung Cancer

Purpose

AMP-activated protein kinase α1 (AMPK α1) associates closely with cancers. However, the relationship between AMPK α1 and non-small cell lung cancer (NSCLC) is not fully understood. In this study, we aim to explore the role and mechanism of AMPK α1 in NSCLC initiation and progression.

Materials and Methods

A total of 165 clinical NSCLC specimens were included in the formalin-fixed and paraffin-embedded (FFPE) lung cancer tissue arrays. The expression levels of AMPK α1 and thioredoxin (Trx) in NSCLC cancer tissues and adjacent non-tumor lung tissues were measured through using immunohistochemistry. MTT assay was used to detect cell proliferation. Intracellular ROS levels were measured by using H2DCFDA reagent. Lentiviruses including LV-PRKAA1-RNAi, LV-PRKAA1 and a negative LV-control were used to infect A549 cells to modulate AMPK α1 expression in vitro. Immunoblotting was used to determine the modulation relationship between AMPK α1 and Trx. Log rank test and Kaplan–Meier survival analysis were performed to evaluate the significances of AMPK α1 and Trx expression levels on NSCLC patients’ prognoses.

Results

AMPK α1 was highly expressed in NSCLC cancer tissues and correlated with poor prognosis in patients with NSCLC. In A549 cells, overexpression of AMPK α1 promoted proliferation, suppressed ROS levels and inhibited apoptosis. Moreover, inhibition of AMPK α1 expression achieved the opposite effects. Trx was significantly overexpressed in NSCLC cancer tissues; furthermore, Trx expressed much more in cytoplasm when compared with cell nucleus. Trx expression levels were positively correlated with AMPK α1 expression levels in NSCLC tissues. AMPK α1 could regulate Trx in A549 cells. No significant correlations were observed between Trx expression variances and prognoses in NSCLC patients. Combination of AMPK α1 and Trx had no advantage in predicting prognoses of NSCLC patients.

Conclusion

These results suggest that AMPK α1 serves a carcinogenic role at least in part through the regulation of Trx expression, and thus represents a potential treatment target in patients with NSCLC.

Morphine Addiction and Oxidative Stress: The Potential Effects of Thioredoxin-1

Long-term administration of morphine for the management of chronic pain will result in tolerance to its analgesic effect and could even cause drug dependence. Numerous studies have demonstrated significant redox alteration in morphine dependence and addiction. Thioredoxin-1 (Trx-1) play important roles in controlling the cellular redox balance. In recent years, several recent studies have demonstrated that Trx-1 may be a promising novel therapeutic target for morphine addiction. In this article, we firstly review the redox alteration in morphine addiction. We also summarize the expression and the protective roles of Trx-1 in morphine dependence. We further highlight the protection of geranylgeranylacetone (GGA), a noncytotoxic pharmacological inducer of Trx-1, in morphine-induced conditioned place preference. In conclusion, Trx-1 may be very promising for clinical therapy of morphine addiction in the future.

Gemcitabine inhibits cisplatin resistance in cisplatin-resistant A549 cells by upregulating trx-interacting protein and inducing cell cycle arrest

Cisplatin is a main chemotherapeutic drug used to treat non-small-cell lung cancer patients. However, these patients commonly face cisplatin resistance. The roles and underlying mechanisms of gemcitabine, irinotecan, pemetrexed and docetaxel used as single agents or combined with cisplatin for overcoming cisplatin-resistant non-small-cell lung cancer were explored in this study. MTT assays showed that gemcitabine alone exhibited stronger cytotoxicity on cisplatin-resistant A549 cells than irinotecan, pemetrexed and docetaxel. Meanwhile, gemcitabine combined with cisplatin showed a synergistic inhibitory effect on cisplatin-resistant cells. RNA sequencing and Gene Ontology/Kyoto Encyclopedia of Genes and Genomes analysis showed that cell cycle signaling pathways and trx-interacting protein were factors in the efficacy of the cotreatment. Flow cytometry and Western blot results showed that when cisplatin-resistant A549 cells were cotreated with gemcitabine and cisplatin, G0/G1 phase arrest occurred, and trx-interacting protein was upregulated. Silencing trx-interacting protein attenuated the response of the resistant cells to the drug combination. A trx-interacting protein agonist together with cisplatin showed an additive cytotoxic effect on the resistant cells compared with cisplatin alone. The gemcitabine and cisplatin combination, compared to gemcitabine or PBS alone, markedly suppressed the growth of cisplatin-resistant A549 tumors in vivo, accompanied by an increase in trx-interacting protein and a decrease in Ki67 expression. Therefore, we concluded that gemcitabine and cisplatin, as an FDA-approved combination, is a viable therapy for cisplatin-resistant non-small-cell lung cancer ex vivo and in vivo.

Plasma activity of Thioredoxin Reductase as a Novel Biomarker in Gastric Cancer

Gastric cancer (GC) is one of the leading malignancies around the world. Identification of novel and efficient biomarkers for GC diagnosis and evaluation of therapeutic efficiency could improve the therapeutic strategy in future clinical application. This study aims to evaluate the levels of plasma thioredoxin reductase (TrxR) activity in GC patients to confirm its validity and efficacy in GC diagnosis and evaluation of therapeutic efficiency. 923 cases were enrolled in the current study. In the group of GC patients before clinical intervention, plasma TrxR activity [9.09 (7.96, 10.45) U/mL] was significantly higher than in healthy controls [3.69 (2.38, 5.32) U/mL]. The threshold of TrxR activity for GC diagnosis was set at 7.34 U/mL with a sensitivity of 85.5% and a specificity of 97.9%. In GC patients after chemotherapy, plasma TrxR activity was remarkably higher in patients with progressive disease or uncontrolled condition [10.07 (8.19, 11.02) U/mL] compared with patients with complete or partial response [7.12 (6.08, 8.37) U/mL] in response to chemotherapy. TrxR activity displayed the higher efficiency to distinguish between GC patients with two distinct clinical outcomes than carcinoembryonic antigen (CEA), cancer antigen 72-4 (CA72-4) and cancer antigen 19-9 (CA19-9). Moreover, combination of TrxR, CEA, CA72-4 and CA19-9 was demonstrated to be more effective in both GC diagnosis and evaluation of therapeutic efficiency than was each biomarker individually. Together, plasma TrxR activity was identified as a novel and efficient biomarker of GC, both in diagnosis and monitoring of therapeutic efficiency in response to chemotherapy.

D-Allose, a Stereoisomer of D-Glucose, Extends the Lifespan of Caenorhabditis elegans via Sirtuin and Insulin Signaling

D-Allose (D-All), C-3 epimer of D-glucose, is a rare sugar known to suppress reactive oxygen species generation and prevent hypertension. We previously reported that D-allulose, a structural isomer of D-All, prolongs the lifespan of the nematode Caenorhabditis elegans. Thus, D-All was predicted to affect longevity. In this study, we provide the first empirical evidence that D-All extends the lifespan of C. elegans. Lifespan assays revealed that a lifespan extension was induced by 28 mM D-All. In particular, a lifespan extension of 23.8 % was achieved (p < 0.0001). We further revealed that the effects of D-All on lifespan were dependent on the insulin gene daf-16 and the longevity gene sir-2.1, indicating a distinct mechanism from those of other hexoses, such as D-allulose, with previously reported antiaging effects.