Increased Thioredoxin-1 Expression Promotes Cancer Progression and Predicts Poor Prognosis in Patients with Gastric Cancer

Exploring the Thioredoxin System as a Therapeutic Target in Cancer: Mechanisms and Implications

Cells constantly face the challenge of managing oxidants. In aerobic organisms, oxygen (O2) is used for energy production, generating reactive oxygen species (ROS) as byproducts of enzymatic reactions. To protect against oxidative damage, cells possess an intricate system of redox scavengers and antioxidant enzymes, collectively forming the antioxidant defense system. This system maintains the redox equilibrium and enables the generation of localized oxidative signals that regulate essential cellular functions. One key component of this defense is the thioredoxin (Trx) system, which includes Trx, thioredoxin reductase (TrxR), and NADPH. The Trx system reverses oxidation of macromolecules and indirectly neutralizes ROS via peroxiredoxin (Prx). This dual function protects cells from damage accumulation and supports physiological cell signaling. However, the Trx system also shields tumors from oxidative damage, aiding their survival. Due to elevated ROS levels from their metabolism, tumors often rely on the Trx system. In addition, the Trx system regulates critical pathways such as proliferation and neoangiogenesis, which tumors exploit to enhance growth and optimize nutrient and oxygen supply. Consequently, the Trx system is a potential target for cancer therapy. The challenge lies in selectively targeting malignant cells without disrupting the redox equilibrium in healthy cells. The aim of this review article is threefold: first, to elucidate the function of the Trx system; second, to discuss the Trx system as a potential target for cancer therapies; and third, to present the possibilities for inhibiting key components of the Trx system, along with an overview of the latest clinical studies on these inhibitors.

Thioredoxin system in colorectal cancer: Its role in carcinogenesis, disease progression, and response to treatment

The thioredoxin system is essential for many physiological processes, including the maintenance of redox signalling pathways. Alterations in the activity, expression and interactions with other signalling pathways can lead to protective or pathophysiological responses. Thioredoxin and thioredoxin reductase, the two main components of this system, are often overexpressed in cancer, including colorectal cancer. This overexpression is often linked with tumour progression and poor outcomes. This review discusses the role of the Trx system in driving colorectal carcinogenesis and disease progression, as well as the challenges of targeting this system. Additionally, the recent advancements in the development of novel and effective thioredoxin inhibitors for colorectal cancer are also explored.

Pharmacodynamic and Toxicity Studies of 6-Isopropyldithio-2'-guanosine Analogs in Acute T-Lymphoblastic Leukemia

(1) Background: The research group has developed a new small molecule, 6-Isopropyldithio-2'-deoxyguanosine analogs-YLS004, which has been shown to be the most sensitive in acute T-lymphoblastic leukemia cells. Moreover, it was found that the structure of Nelarabine, a drug used to treat acute T-lymphoblastic leukemia, is highly similar to that of YLS004. Consequently, the structure of YLS004 was altered to produce a new small molecule inhibitor for this study, named YLS010. (2) Results: YLS010 has exhibited potent anti-tumor effects by inducing cell apoptosis and ferroptosis. A dose gradient was designed for in vivo experiments based on tentative estimates of the toxicity dose using acute toxicity in mice and long-term toxicity in rats. The study found that YLS010 at a dose of 8 mg/kg prolonged the survival of late-stage acute T-lymphoblastic leukemia mice in the mouse model study. (3) Conclusions: YLS010 has demonstrated specific killing effects against acute T-lymphoblastic leukemia both in vivo and in vitro. Preclinical studies of YLS010 offer a new opportunity for the treatment of patients with acute T-lymphoblastic leukemia in clinical settings.

Inhibition of thioredoxin-1 enhances the toxicity of glycolysis inhibitor 2-deoxyglucose by downregulating SLC1A5 expression in colorectal cancer cells

BACKGROUND

Targeting glycolysis in cancer is an attractive approach for therapeutic intervention. 2-Deoxyglucose (2DG) is a synthetic glucose analog that inhibits glycolysis. However, its efficacy is limited by the systemic toxicity at high doses. Understanding the mechanism of 2DG resistance is important for further use of this drug in cancer treatment.

METHODS

The expression of thioredoxin-1 (Trx-1) in colorectal cancer (CRC) cells treated with 2DG was detected by Western blotting. The effect of Trx-1 on the cytotoxicity of 2DG in CRC cells was examined in vitro and in vivo. The molecular mechanism involved in Trx-1-mediated activation of the SLC1A5 gene promoter activity was elucidated using in vitro models.

RESULTS

Inhibition glycolysis with 2DG increased the expression of Trx-1 in CRC cells. Overexpression of Trx-1 decreased the cytotoxicity of 2DG, whereas knockdown of Trx-1 by shRNA significantly increased the cytotoxicity of 2DG in CRC cells. The Trx-1 inhibitor PX-12 increased the cytotoxicity of 2DG on CRC cells both in vitro and in vivo. In addition, Trx-1 promoted SLC1A5 expression by increasing the promoter activity of the SLC1A5 gene by binding to SP1. We also found that the SLC1A5 expression was upregulated in CRC tissues, and inhibition of SLC1A5 significantly enhanced the inhibitory effect of 2DG on the growth of CRC cells in vitro and in vivo. Overexpression of SLC1A5 reduced the cytotoxicity of 2DG in combination with PX-12 treatment in CRC cells.

CONCLUSION

Our results demonstrate a novel adaptive mechanism of glycolytic inhibition in which Trx-1 increases GSH levels by regulating SLC1A5 to rescue cytotoxicity induced by 2DG in CRC cells. Inhibition of glycolysis in combination with inhibition of Trx-1 or SLC1A5 may be a promising strategy for the treatment of CRC.

Antiproliferative, antimigratory, and apoptotic effects of diffractaic and vulpinic acids as thioredoxin reductase 1 inhibitors on cervical cancer

Cervical cancer is among the most frequently observed cancer types in females. New therapeutic targets are needed because of the side impacts of existing cancer drugs and the inadequacy of treatment methods. Thioredoxin reductase 1 (TrxR1) is often overexpressed in many cancer cells, and targeting TrxR1 has become an attractive target for cancer therapy. This study investigated the anticancer impacts of diffractaic and vulpinic acids, lichen secondary metabolites, on the cervical cancer HeLa cell line. XTT findings demonstrated showed that diffractaic and vulpinic acids suppressed the proliferation of HeLa cells in a dose- and time-dependent manner and IC50 values were 22.52 μg/ml and 66.53 μg/ml at 48 h, respectively. Each of these lichen metabolites significantly suppressed migration. Diffractaic acid showed an increase in both the BAX/BCL2 ratio by qPCR analysis and the apoptotic cell population via flow cytometry analysis on HeLa cells. Concerning vulpinic acid, although it decreased the BAX/BCL2 ratio in this cells, it increased apoptotic cells according to the flow cytometry analysis results. Diffractaic and vulpinic acids significantly suppressed TrxR1 enzyme activity rather than the gene and protein expression levels in HeLa cells. This research demonstrated for the first time, that targeting TrxR1 with diffractaic and vulpinic acids was an effective therapeutic strategy for treating cervical cancer.

Cu(II)-acylhydrazone complex, a potent and selective antitumor agent against human osteosarcoma: Mechanism of action studies over in vitro and in vivo models

Osteosarcoma (OS) is a frequent bone cancer, affecting largely children and young adults. Cisplatin (CDDP) has been efficacious in the treatment of different cancer such us OS but the development of chemoresistance and important side effects leading to therapeutic failure. Novel therapies including copper compounds have shown to be potentially effective as anticancer drugs and one alternative to usually employed platinum compounds. The goal of this work is the evaluation of the in vitro and in vivo antitumoral activity and dilucidate the molecular target of a Cu(II) cationic complex containing a tridentate hydrazone ligand, CuHL for short, H2L=N'-'-(2-hydroxy-3-methoxybenzylidene)thiophene-2-carbohydrazide, against human OS MG-63 cells. Anticancer activity on MG-63 cell line was evaluated in OS monolayer and spheroids. CuHL significantly impaired cell viability in both models (IC50 2D: 2.1 ± 0.3 μM; 3D: 9.1 ± 1.0 μM) (p < 0.001). Additional cell studies demonstrated the copper compound inhibits cell proliferation and conveys cells to apoptosis, determined by flow cytometry. CuHL showed a great genotoxicity, evaluated by comet assay. Proteomic analysis by Orbitrap Mass Spectometry identified 27 differentially expressed proteins: 17 proteins were found overexpressed and 10 underexpressed in MG-63 cells after the CuHL treatment. The response to unfolded protein was the most affected biological process. In addition, in vivo antitumor effects of the compound were evaluated on human OS tumors xenografted in nude mice. CuHL treatment, at a dose of 2 mg/kg i.p., given three times/week for one month, significantly inhibited the progression of OS xenografts and was associated to a reduction in mitotic index and to an increment of tumor necrosis (p < 0.01). Administration of standard-of-care cytotoxic agent CDDP, following the same treatment schedule as CuHL, failed to impair OS growth and progression.

Reanalysis of single-cell data reveals macrophage subsets associated with the immunotherapy response and prognosis of patients with endometrial cancer

Endometrial cancer (EC) is an aggressive gynecological malignancy with an increased incidence rate. The immune landscape crucially affects immunotherapy efficacy and prognosis in EC patients. Here, we characterized the distinct tumor microenvironment signatures of EC tumors by analyzing single-cell RNA sequencing data from Gene Expression Omnibus and bulk RNA sequencing data from The Cancer Genome Atlas, which were compared with normal endometrium. Three macrophage subsets were identified, and two of them showed tissue-specific distribution. One of the macrophage subsets was dominant in macrophages derived from EC and exhibited characteristic behaviors such as promoting tumor growth and metastasis. One of the other macrophage subsets was mainly found in normal endometrium and served functions related to antigen presentation. We also identified a macrophage subset that was found in both EC and normal endometrial tissue. However, the pathway and cellular cross-talk of this subset were completely different based on the respective origin, suggesting a tumor-related differentiation mechanism of macrophages. Additionally, the tumor-enriched macrophage subset was found to predict immunotherapy responses in EC. Notably, we selected six genes from macrophage subset markers that could predict the survival of EC patients, SCL8A1, TXN, ANXA5, CST3, CD74 and NANS, and constructed a prognostic signature. To verify the signature, we identified immunohistochemistry for the tumor samples of 83 EC patients based on the selected genes and further followed up with the survival of the patients. Our results provide strong evidence that the signature can effectively predict the prognosis of EC patients.

The Importance of Thioredoxin-1 in Health and Disease

Thioredoxin-1 (Trx-1) is a multifunctional protein ubiquitously found in the human body. Trx-1 plays an important role in various cellular functions such as maintenance of redox homeostasis, proliferation, and DNA synthesis, but also modulation of transcription factors and control of cell death. Thus, Trx-1 is one of the most important proteins for proper cell and organ function. Therefore, modulation of Trx gene expression or modulation of Trx activity by various mechanisms, including post-translational modifications or protein-protein interactions, could cause a transition from the physiological state of cells and organs to various pathologies such as cancer, and neurodegenerative and cardiovascular diseases. In this review, we not only discuss the current knowledge of Trx in health and disease, but also highlight its potential function as a biomarker.

Mass spectroscopy-based proteomics and metabolomics analysis of triple-positive breast cancer cells treated with tamoxifen and/or trastuzumab

PURPOSE

HER2-enriched breast cancer with high levels of hormone receptor expression, known as "triple positive" breast cancer, may represent a new entity with a relatively favourable prognosis against which the combination of chemotherapy, HER-2 inhibition, and endocrine treatment may be considered overtreatment. We explored the effect of the anticancer drugs tamoxifen and trastuzumab, both separately and in combination, on the integrated proteomic and metabolic profile of "triple positive" breast cancer cells (BT-474).

METHOD

We employed ultra-high-performance liquid chromatography-quadrupole time of flight mass spectrometry using a Bruker timsTOF to investigate changes in BT-474 cell line treated with either tamoxifen, trastuzumab or a combination. Differentially abundant metabolites were identified using the Bruker Human Metabolome Database metabolite library and proteins using the Uniprot proteome for Homo sapiens using MetaboScape and MaxQuant, respectively, for identification and quantitation.

RESULTS

A total of 77 proteins and 85 metabolites were found to significantly differ in abundance in BT-474 treated cells with tamoxifen 5 μM/and or trastuzumab 2.5 μM. Findings suggest that by targeting important cellular signalling pathways which regulate cell growth, apoptosis, proliferation, and chemoresistance, these medicines have a considerable anti-growth effect in BT-474 cells. Pathways enriched for dysregulation include RNA splicing, neutrophil degranulation and activation, cellular redox homeostasis, mitochondrial transmembrane transport, ferroptosis and necroptosis, ABC transporters and central carbon metabolism.

CONCLUSION

Our findings in protein and metabolite level research revealed that anti-cancer drug therapy had a significant impact on the key signalling pathways and molecular processes in triple positive BT-474 cell lines.

Thioredoxin reductase selenoproteins from different organisms as potential drug targets for treatment of human diseases

Human thioredoxin reductase (TrxR) is a selenoprotein with a central role in cellular redox homeostasis, utilizing a highly reactive and solvent-exposed selenocysteine (Sec) residue in its active site. Pharmacological modulation of TrxR can be obtained with several classes of small compounds showing different mechanisms of action, but most often dependent upon interactions with its Sec residue. The clinical implications of TrxR modulation as mediated by small compounds have been studied in diverse diseases, from rheumatoid arthritis and ischemia to cancer and parasitic infections. The possible involvement of TrxR in these diseases was in some cases serendipitously discovered, by finding that existing clinically used drugs are also TrxR inhibitors. Inhibiting isoforms of human TrxR is, however, not the only strategy for human disease treatment, as some pathogenic parasites also depend upon Sec-containing TrxR variants, including S. mansoni, B. malayi or O. volvulus. Inhibiting parasite TrxR has been shown to selectively kill parasites and can thus become a promising treatment strategy, especially in the context of quickly emerging resistance towards other drugs. Here we have summarized the basis for the targeting of selenoprotein TrxR variants with small molecules for therapeutic purposes in different human disease contexts. We discuss how Sec engagement appears to be an indispensable part of treatment efficacy and how some therapeutically promising compounds have been evaluated in preclinical or clinical studies. Several research questions remain before a wider application of selenoprotein TrxR inhibition as a first-line treatment strategy might be developed. These include further mechanistic studies of downstream effects that may mediate treatment efficacy, identification of isoform-specific enzyme inhibition patterns for some given therapeutic compounds, and the further elucidation of cell-specific effects in disease contexts such as in the tumor microenvironment or in host-parasite interactions, and which of these effects may be dependent upon the specific targeting of Sec in distinct TrxR isoforms.

Glutathione-dependent thioredoxin reduction and lipoamide system support in-vitro mammalian ribonucleotide reductase catalysis: a possible antioxidant redundancy

BACKGROUND

The thioredoxin system (Trx), comprising of Trx, Thioredoxin reductase (TrxR) and NADPH aids in donating hydrogen group to support Ribonucleotide reductase (RNR) catalysis during de-novo DNA biosynthesis. However, it has been observed that inhibiting TrxR does not affect the viability of cancer cells that are susceptible to pharmacological glutathione (GSH) depletion. This prompted us to study the potential antioxidant redundancies that might prolong RNR activity.

METHODS

To study the RNR activity assay, the RNR complex was reconstituted by mixing purified mouse recombinant RNR subunits and the conversion of [³ H] CDP into [³ H] dCDP was monitored. In the assay system, either purified Trx and GSH or Lipoamide system was supplemented as reducing agents to support RNR catalysis.

RESULTS

Herein, we have found that GSH-dependent Trx reduction supports mammalian class I RNR catalysis in absence of TrxR in the system. Our data also presents the first report that the LAM system is capable of supporting in-vitro RNR activity in the complete absence of either Trx or Grx systems.

CONCLUSIONS

We conclude that GSH-mediated Trx reduction and LAM systems support basal level RNR activity in vitro; in absence of TrxR and complete redoxin systems respectively and hypothesize that potential redundancy between the various antioxidant systems might synergize in sustaining RNR activity.

The blood level of thioredoxin 1 as a supporting biomarker in the detection of breast cancer

BACKGROUND

There is a long-time unmet need for a means to detect breast cancer (BC) using blood. Although mammography is accepted as the gold standard for screening, a blood-based diagnostic can complement mammography and assist in the accurate detection of BC in the diagnostic process period of early diagnosis. We have previously reported the possible use of thioredoxin 1 (Trx1) in serum as a novel means to detect BC. In the present study, we validated the clinical utility of Trx1 to identify BC by testing sera from biopsy-confirmed cancer patients and women without cancer.

METHODS

We have generated monoclonal antibodies against Trx1 and developed an ELISA kit that can quantitate Trx1 in sera. The level of Trx1 was determined in each serum from women without cancer (n = 114), as well as in serum from patients with BC (n = 106) and other types of cancers (n = 74), including cervical, lung, stomach, colorectal, and thyroid cancer. The sera from BC patients were collected and classified by the subjects' age and cancer stage. In addition to the Trx1 levels of BC patients, several pathological and molecular aspects of BC were analyzed. Test results were retrospectively compared to those from mammography. Each test was duplicated, and test results were analyzed by ROC analysis, one-way ANOVA tests, and unpaired t-tests.

RESULTS

The mean level of Trx1 from women without cancer was 5.45 ± 4.16 (±SD) ng/ml, that of the other malignant cancer patient group was 2.70 ± 2.01 ng/ml, and that from the BC group was 21.96 ± 6.79 ng/ml. The difference among these values was large enough to distinguish BC sera from non-BC control sera with a sensitivity of 97.17% and specificity of 94.15% (AUC 0.990, p < 0.0001). Most Trx1 levels from BC patients' sera were higher than the cut-off value of 11.4 ng/ml regardless of age, stage, histological grade, type, and specific receptors' expression profile of BC. The level of Trx1 could rescue women from most cases of misread or incomplete mammography diagnoses.

CONCLUSION

These results indicated that the blood level of Trx1 could be an effective and accurate means to assist the detection of BC during the early diagnosis period.

Cloning and characterization of Thioredoxin 1 from the Cnidarian Hydra

Thioredoxins, small disulphide-containing redox proteins, play an important role in the regulation of cellular thiol redox balance through their disulfide reductase activity. In this study, we have identified, cloned, purified and characterized thioredoxin 1 (HvTrx1) from the Cnidarian Hydra vulgaris Ind-Pune. Bioinformatics analysis revealed that HvTrx1 contains an evolutionarily conserved catalytic active site CGPC and shows a closer phylogenetic relationship with vertebrate Trx1. Optimum pH and temperature for enzyme activity of purified HvTrx1 was found to be pH 7.0 and 25 °C respectively. Enzyme activity decreased significantly at acidic or alkaline pH as well as at higher temperatures. HvTrx1 was found to be expressed ubiquitously in whole mount in situ hybridization. Treatment of Hydra with hydrogen peroxide (H2O2), a highly reactive oxidizing agent, led to a significant increase in gene expression and enzyme activity of Trx1. Further experiments using PX12, an inhibitor of Trx1, indicated that Trx1 plays an important role in regeneration in Hydra. Finally, by using growth assay in E. coli and wound healing assay in human colon cancer cells, we demonstrate that HvTrx1 is functionally active in both prokaryotic and eukaryotic heterologous systems.

The double-edged roles of ROS in cancer prevention and therapy

Reactive oxygen species (ROS) serve as cell signaling molecules generated in oxidative metabolism and are associated with a number of human diseases. The reprogramming of redox metabolism induces abnormal accumulation of ROS in cancer cells. It has been widely accepted that ROS play opposite roles in tumor growth, metastasis and apoptosis according to their different distributions, concentrations and durations in specific subcellular structures. These double-edged roles in cancer progression include the ROS-dependent malignant transformation and the oxidative stress-induced cell death. In this review, we summarize the notable literatures on ROS generation and scavenging, and discuss the related signal transduction networks and corresponding anticancer therapies. There is no doubt that an improved understanding of the sophisticated mechanism of redox biology is imperative to conquer cancer.

The NRF2, Thioredoxin, and Glutathione System in Tumorigenesis and Anticancer Therapies

Cancer remains an elusive, highly complex disease and a global burden. Constant change by acquired mutations and metabolic reprogramming contribute to the high inter- and intratumor heterogeneity of malignant cells, their selective growth advantage, and their resistance to anticancer therapies. In the modern era of integrative biomedicine, realizing that a personalized approach could benefit therapy treatments and patients' prognosis, we should focus on cancer-driving advantageous modifications. Namely, reactive oxygen species (ROS), known to act as regulators of cellular metabolism and growth, exhibit both negative and positive activities, as do antioxidants with potential anticancer effects. Such complexity of oxidative homeostasis is sometimes overseen in the case of studies evaluating the effects of potential anticancer antioxidants. While cancer cells often produce more ROS due to their increased growth-favoring demands, numerous conventional anticancer therapies exploit this feature to ensure selective cancer cell death triggered by excessive ROS levels, also causing serious side effects. The activation of the cellular NRF2 (nuclear factor erythroid 2 like 2) pathway and induction of cytoprotective genes accompanies an increase in ROS levels. A plethora of specific targets, including those involved in thioredoxin (TRX) and glutathione (GSH) systems, are activated by NRF2. In this paper, we briefly review preclinical research findings on the interrelated roles of the NRF2 pathway and TRX and GSH systems, with focus given to clinical findings and their relevance in carcinogenesis and anticancer treatments.

Sodium Butyrate Selectively Kills Cancer Cells and Inhibits Migration in Colorectal Cancer by Targeting Thioredoxin-1

Background

Sodium butyrate (NaB) is a short-chain fatty acid which is produced by bacterial fermentation of nondigestible dietary fiber and has been reported to exert anti-tumor effects in many tumors including colorectal cancer (CRC). However, the role of thioredoxin-1 (Trx-1) in NaB-induced anti-tumor effect has not been completely clarified.

Materials and Methods

Effects of NaB on the growth of CRC cell lines HT29 and SW480 were detected by the Cell Counting Kit-8 (CCK-8) and colony formation assays. The apoptotic cells were determined by flow cytometry, and cell migration was assessed by a Transwell assay. Western blot analysis was used to test the Trx-1 and epithelial-to-mesenchymal transition (EMT)-related proteins level. Reactive oxygen species (ROS) level was determined and N-acetylcysteine (NAC) recovery experiment was performed in CRC cells. In addition, mice xenograft model was established to test the effect of NaB on CRC growth in vivo. Further, the effects of NaB on CRC cells with overexpression or knockdown were tested by the CCK-8 and Transwell assays.

Results

NaB treatment significantly inhibited cell growth and decreased Trx-1 protein expression in CRC cells but not in normal colon epithelial cells. NaB also induced apoptosis, inhibited colony formation, migration and EMT in CRC cells. Besides, NaB increased ROS level in CRC cells and NAC reversed NaB-induced inhibition of cell proliferation. Moreover, downregulation of Trx-1 significantly enhanced NaB-induced inhibitory effects on cell growth and migration, whereas overexpression of Trx-1 attenuated NaB-induced inhibitory effects on growth and migration in CRC cells.

Conclusion

These findings indicate that the NaB-mediated anti-tumor effects on CRC cells are related to downregulation of Trx-1.

Identification of Prognostic Candidate Genes in Breast Cancer by Integrated Bioinformatic Analysis

Breast cancer is one of the most common malignancies. However, the molecular mechanisms underlying its pathogenesis remain to be elucidated. The present study aimed to identify the potential prognostic marker genes associated with the progression of breast cancer. Weighted gene coexpression network analysis was used to construct free-scale gene coexpression networks, evaluate the associations between the gene sets and clinical features, and identify candidate biomarkers. The gene expression profiles of GSE48213 were selected from the Gene Expression Omnibus database. RNA-seq data and clinical information on breast cancer from The Cancer Genome Atlas were used for validation. Four modules were identified from the gene coexpression network, one of which was found to be significantly associated with patient survival time. The expression status of 28 genes formed the black module (basal); 18 genes, dark red module (claudin-low); nine genes, brown module (luminal), and seven genes, midnight blue module (nonmalignant). These modules were clustered into two groups according to significant difference in survival time between the groups. Therefore, based on betweenness centrality, we identified TXN and ANXA2 in the nonmalignant module, TPM4 and LOXL2 in the luminal module, TPRN and ADCY6 in the claudin-low module, and TUBA1C and CMIP in the basal module as the genes with the highest betweenness, suggesting that they play a central role in information transfer in the network. In the present study, eight candidate biomarkers were identified for further basic and advanced understanding of the molecular pathogenesis of breast cancer by using co-expression network analysis.