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Drug toxicity in relation to TrxR1 levels. (A and B) Upper four rows show the distribution between live and dead cells (dark gray, live cells, and light gray, dead cells) after the corresponding treatments as indicated. Means ± SEM from at least two independent experiments done in triplicate are shown. The bottom rows show the percentage of dead cells of the total cell number per well for mock-or Siseq1-treated cells. Signi fi cant differences in sensitivity are indicated: ⁎ p b 0.05, ⁎⁎ p b 0.01, or ⁎⁎⁎ p b 0.001.
Source publication
The selenoprotein thioredoxin reductase 1 (TrxR1) is currently recognized as a plausible anticancer drug target. Here we analyzed the effects of TrxR1 targeting in the human A549 lung carcinoma cell line, having a very high basal TrxR1 expression. We determined the total cellular TrxR activity to be 271.4 +/- 39.5 nmol min(-1) per milligram of tota...
Contexts in source publication
Context 1
... and as analyzed in crude cell extracts (Table 1). Analyzing the potential cell death induced by these compounds revealed that TrxR1 knockdown significantly sensitized A549 cells to treatment with DNCB (in the concentration range of 2.5- 10 μM) or menadione (5-10 μM), whereas there was no difference in sensitivity to auranofin upon TrxR1 knockdown (Fig. 5A). In contrast, the cells surprisingly became less susceptible to the cytotoxicity of cDDP (usingb20 μM) upon TrxR1 knockdown, whereas there was no change in the sensitivity to Oxa or juglone (Fig. ...
Context 2
... (in the concentration range of 2.5- 10 μM) or menadione (5-10 μM), whereas there was no difference in sensitivity to auranofin upon TrxR1 knockdown (Fig. 5A). In contrast, the cells surprisingly became less susceptible to the cytotoxicity of cDDP (usingb20 μM) upon TrxR1 knockdown, whereas there was no change in the sensitivity to Oxa or juglone (Fig. ...
Citations
... [15,46,47] Therefore, we exemplary evaluated the inhibition of 1 and 2 and compared them to one of the most potent gold-based TrxR inhibitors, auranofin, in an end-point insulin reduction-based and DTNB-coupled microplate reader assay in cellulo (Table 2). [48] The A549 lung carcinoma cells were selected for these experiments due to their high basal expression of TrxR compared to the other cancer cell lines, [49] and, most notably, for the marked antiproliferative effects of 2 towards these cells. According to the enzyme inhibition data, whereas ligand 1 alone is not able to exhibit TrxR inhibition in the tested range of concentrations, gold complex 2 shows an IC 50 of 0.57 μM, which is only slightly less active (1.9-fold) than the reference auranofin (IC 50 0.32 μM) (SI, Figure S6) but more active than other gold complexes that we had recently studied with the same assay. ...
A dinuclear gold(I) complex featuring a strongly donating bis‐N‐heterocyclic imine ligand was synthesised and characterised by different methods, including single crystal X‐ray diffraction (SC‐XRD) analysis. The compound has been tested for its antiproliferative effects in a panel of human cancer cell lines in vitro, showing highly selective anticancer effects, particularly against human A549 non‐small cell lung cancer cells (NSCLC), with respect to non‐tumorigenic cells (VERO). The accumulation of the compound in A549 and VERO cells was studied by high‐resolution continuum source atomic absorption spectrometry (HRCS‐AAS), revealing that the anticancer effects are not particularly related to the different amounts of gold taken up by the cells over 72 h. Enzyme inhibition studies to evaluate the activity of the seleno‐enzyme thioredoxin reductase (TrxR) in cancer cell extracts show that the gold(I) compound is a potent inhibitor (IC50=0.567±0.208 μM), while the free ligand is ineffective. This result correlates with the observed compound's selectivity towards A549 cells overexpressing the enzyme.
... Then, it is important to pay attention to the selenium concentration in the cell culture medium when looking at the activity of selenoproteins (such as TrxR or glutathione peroxidase, GPx) [57]. Few studies have been carried out on the correlation between the quantity of Se and their activity, and in turn, on drugs' cytotoxicity [58][59][60]. As an example, in 2012, Arnér and collaborators brought to light the subtle effect of selenium concentration on the antiproliferative activity of cisplatin. ...
Simple Summary
The identification of biological targets is an essential step in deciphering the mechanism of action of anticancer drugs. In this review, we chose to study the relationship between the inhibition of thioredoxin reductase (TrxR), a key enzyme in maintaining the redox balance of cells, and the cytotoxic effects of two groups of organometallic complexes. The first group is essentially composed of Au(I) and Au(III) complexes and the second one comprises metallocifens (organometallic complexes derived from tamoxifen). The results show that these two groups interact differently with TrxR at the molecular level. Even if the contribution of TrxR inhibition to the cytotoxicity of complexes is clearly established for many of them, the number of complexes for which TrxR inhibition plays a predominant role appears quite limited. Eventually, the antiproliferative activity of most of the complexes appears to stem from the interaction with several targets, a favorable strategy to tackle MDR tumors.
Abstract
Cancers classified as multidrug-resistant (MDR) are a family of diseases with poor prognosis despite access to increasingly sophisticated treatments. Several mechanisms explain these resistances involving both tumor cells and their microenvironment. It is now recognized that a multi-targeting approach offers a promising strategy to treat these MDR tumors. Inhibition of thioredoxin reductase (TrxR), a key enzyme in maintaining redox balance in cells, is a well-identified target for this approach. Auranofin was the first inorganic gold complex to be described as a powerful inhibitor of TrxR. In this review, we will first recall the main results obtained with this metallodrug. Then, we will focus on organometallic complexes reported as TrxR inhibitors. These include gold(I), gold(III) complexes and metallocifens, i.e., organometallic complexes of Fe and Os derived from tamoxifen. In these families of complexes, similarities and differences in the molecular mechanisms of TrxR inhibition will be highlighted. Finally, the possible relationship between TrxR inhibition and cytotoxicity will be discussed and put into perspective with their mode of action.
... This excess of TrxR could be necessary to perform other functions, or in case of exposure to inhibition factors. When TrxR was inhibited by 90% in HeLa (human cell line) cells, Trx1 remained in a reduced state (Eriksson et al. 2009). Small interfering RNA knocked down TrxR1 by 90% in A549 (human epithelial cell) cells but did not seem to affect Trx activity or inhibit cell growth (Watson et al. 2008). ...
Mercury (Hg) exposure has not been examined in many recreational nearshore fish species that are commonly consumed around the Hawaiian Islands. Specific gene transcripts, such as metallothionein (MET) and thioredoxin reductase (TrxR), can be used to examine Hg exposure responses in aquatic organisms. This study measured total mercury (THg) in four species from two groups of Hawaiian nearshore fishes: giant trevally (Caranx ignobilis, n = 13), bluefin trevally (C. melampygus, n = 4), sharp jaw bonefish (Albula virgata, n = 2), and round jaw bonefish (A. glossodonta, n = 19). Total Hg accumulation and abundance profiles of MET and TrxR were evaluated for muscle, liver, and kidney tissues. Total Hg in round jaw bonefish and giant trevally tissues accumulated with length and calculated age. In round jaw bonefish tissues, mean THg was greater in kidney (1156 ng/g wet mass (wm)) than liver (339 ng/g wm) and muscle (330 ng/g wm). Giant trevally muscle (187 ng/g wm) and liver (277 ng/g wm) mean THg did not differ significantly. Fish species in this study were compared to commercial and local fish species with state and federal muscle tissue consumption advisories based on THg benchmarks developed by the U.S. Food and Drug Administration (FDA) and Environmental Protection Agency (EPA). Both bonefishes had mean muscle THg that exceeded benchmarks suggesting consumption advisories should be considered. MET transcript in round jaw bonefish kidney tissue and kidney THg exhibited a marginally significant positive correlation, while TrxR transcript in liver tissue negatively correlated with increasing liver THg. These results contribute to our understanding of Hg exposure associated health effects in fish.
... Having found that RSL3 inhibits TXNRD1 with similar efficacy as the previously developed TRi-1 and TRi-2 compounds [17], we next compared these three compounds with regards to their efficacies in eliciting cell death, asking whether all three compounds would display similar ferroptotic features in the cell death that they trigger. First, we compared the cytotoxic effects of the three compounds in lung adenocarcinoma A549 cells, which have an unusually high activity and expression of TXNRD1 that is also known to be able to modulate the cytotoxic efficacy of different anticancer drugs [34,35]. Additional expression information for the cell lines used can be found in Extended Data Table 1. ...
Ferroptosis is defined as cell death triggered by iron-dependent lipid peroxidation that is preventable by antioxidant compounds such as ferrostatin-1. Endogenous suppressors of ferroptosis include FSP-1 and the selenoprotein GPX4, the latter of which directly enzymatically reduces lipid hydroperoxides. Small molecules that trigger ferroptosis include RSL3, ML162, and ML210; these compounds are often used in studies of ferroptosis and are generally considered as GPX4 inhibitors. Here, we found that RSL3 and ML162 completely lack capacity of inhibiting the enzymatic activity of recombinant selenoprotein GPX4. Surprisingly, these compounds were instead found to be efficient inhibitors of another selenoprotein, TXNRD1. Other known inhibitors of TXNRD1, including auranofin, TRi-1 and TRi-2, are also efficient inducers of cell death but that cell death could not be suppressed with ferrostatin-1. Our results collectively suggest that prior studies using RSL3 and ML162 may need to be reevaluated in the context of ferroptosis with regards to additional enzyme targets and mechanisms of action that may be involved.
... Growing cells were seeded on 6-plate plates and kept for 24 h. Drug doses were administered using the IC 50 concentration values determined at the end of the procedure. RNA was isolated from the SH-SY5Y cell line in accordance with the protocol in the RNeasy Plus Mini Kit. ...
... It has been known for years that catalase (CAT) is associated with antitumor effect and resistance to chemotherapy [45][46][47][48][49][50] . The development of drug resistance to cancer therapy is a major barrier to the effective treatment of human malignancies. ...
We report herein the synthesis of new azomethine group containing forty-, sixty-eight- and seventy-two-membered macroheterocyclic compounds and the investigation of their activity against the neuroblastoma cell line. The synthesis of targeted compounds was done by condensation of dialdehydes with polyamines and their structures were investigated by 1H and 13C NMR and MALDI MS methods. Anticancer activity of these newly synthesized molecules was studied in the neuroblastoma (SH-SY5Y) cell line at eight different concentrations (1-100µg/ml) for 24 hours, 48 hours and 72 hours by MTT method. In addition to it, oxidative stress (GPX1, PRDX1, CAT, SOD1, NQO1) and DNA repair (ATR, ERCC1, CDKN1A, PRKDC) gene profiles were also investigated by RT-PCR method. It was found that all synthesized compounds showed the highest activity after 72 hours of incubation. PRDX1 gene expression in the case of all investigated compounds was found to be higher than the control group, whereas ABCB1 (MDR) gene expression increased only in the case of molecule 1. Results also demonstrate that the expression levels of GPX and SOD1 genes were high in the case of molecule 2, whereas molecule 1 manifested low expression levels of ERCC1, ATR, CDKN1A, PRKDC, GPX1, ABCB1(MDR), CAT, SOD1 and NQO1 genes. Along with experimental studies, theoretical studies were also carried out. The String v11 program was used to determine the interaction of proteins involved in oxidative stress and DNA repair mechanisms with other proteins. The results of the molecular docking analysis were found to be in good agreement with the experiments.
... We evaluated the ability of 7, 2, cisPt, and a 1 : 1 mixture of 2 and cisPt to inhibit TrxR activity in A549 cells, which highly express TrxR. [25] Using a modified reported method, [26] we performed an end-point insulin reduction assay, where the number of thiol groups was determined spectrophotometrically using DTNB. To eliminate the effects of other cellular reductases, we used two sets of experimental conditions for each concentration of the test compounds; one having recombinant TrxR as the substrate and the other without it. ...
AuI‐carbene and PtIV−AuI‐carbene prodrugs display low to sub‐μM activity against several cancer cell lines and overcome cisplatin (cisPt) resistance. Linking a cisPt‐derived PtIV(phenylbutyrate) complex to a AuI‐phenylimidazolylidene complex 2, yielded the most potent prodrug. While in vivo tests against Lewis Lung Carcinoma showed that the prodrug PtIV(phenylbutyrate)‐AuI‐carbene (7) and the 1 : 1 : 1 co‐administration of cisPt: phenylbutyrate:2 efficiently inhibited tumor growth (≈95 %), much better than 2 (75 %) or cisPt (84 %), 7 exhibited only 5 % body weight loss compared to 14 % for 2, 20 % for cisPt and >30 % for the co‐administration. 7 was much more efficient than 2 at inhibiting TrxR activity in the isolated enzyme, in cells and in the tumor, even though it was much less efficient than 2 at binding to selenocysteine peptides modeling the active site of TrxR. Organ distribution and laser‐ablation (LA)‐ICP‐TOFMS imaging suggest that 7 arrives intact at the tumor and is activated there.
... We inferred that the inhibitory effect of DMF on TXNRD1 works more on the cellular function of TXNRD1 rather than directly generating ROS. Meanwhile, the critical role of TXNRD1 implies that activity loss of TXNRD1 will rewire some cellular processes and alter the tolerance of cells to some stress [38,39]. This may be considered means of DMF for inducing cancer cell death and regulating cellular inflammation. ...
Macrophages secrete a variety of pro-inflammatory cytokines in response to pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) but abnormal release of cytokines unfortunately promotes cytokine storms. Dimethyl fumarate (DMF), an FDA-approved drug for multiple sclerosis (MS) treatment, has been found as an effective therapeutic agent for resolution. In this study, the anti-inflammatory effect of DMF was found to correlate to selenoprotein thioredoxin reductase 1 (TXNRD1). DMF irreversibly modified the Sec498 residue and C-terminal catalytic cysteine residues of TXNRD1 in a time- and dose-dependent manner. In LPS-stimulated RAW 264.7 cells, cellular TXNRD activity was increased through up-regulation of the protein level and DMF inhibited TXNRD activity and the nitric oxide (NO) production of RAW 264.7 cells. Meanwhile, the inhibition of TXNRD1 by DMF would contribute to the redox regulation of inflammation and promote the nuclear factor erythroid 2-related factor 2 (NRF2) activation. Notably, inhibition of cellular TXNRD1 by auranofin or TRi-1 showed anti-inflammatory effect in RAW 264.7 cells. This finding demonstrated that targeting TXNRD1 is a potential mechanism of using immunometabolites for dousing inflammation in response to pathogens and highlights the potential of TXNRD1 inhibitors in immune regulation.
... TRXR1 knockdown in A549 cells decreased their resistance to 1-chloro-2,4-dinitrobenzene or menadione, but at the same time, it significantly increased their resistance to cisplatin. This effect can be explained by TrxR1 protein derivatized with cisplatin being able to induce cell death [71]. ...
... Increased resistance: H 2 O 2 [212,220,224], daunomycin [213], MPP+ [215], menadione, 1-chloro-2,4-dinitrobenzene [71], arsenic trioxide [222,223] Unchanged resistance: dexamethasone, doxorubicin, etoposide [220], auranofin, juglone [71] in vivo Increased resistance: methamphetamine [214,221], sepsis-induced myocardial dysfunction, sham surgery [216], ischemia [217,225], ex vivo ischemia [218], adriamycin [219] TXNL1 in vitro Decreased resistance: cisplatin [226] TXNRD1 in vitro Increased resistance: X-ray [227], H 2 O 2 [224] Cases of spontaneous gene overexpression in tumors resistant to particular therapy types were also reviewed, but only in such cases where the abolition of overexpression of a particular gene led to the abolition of the changed phenotype. ...
... Increased resistance: H 2 O 2 [212,220,224], daunomycin [213], MPP+ [215], menadione, 1-chloro-2,4-dinitrobenzene [71], arsenic trioxide [222,223] Unchanged resistance: dexamethasone, doxorubicin, etoposide [220], auranofin, juglone [71] in vivo Increased resistance: methamphetamine [214,221], sepsis-induced myocardial dysfunction, sham surgery [216], ischemia [217,225], ex vivo ischemia [218], adriamycin [219] TXNL1 in vitro Decreased resistance: cisplatin [226] TXNRD1 in vitro Increased resistance: X-ray [227], H 2 O 2 [224] Cases of spontaneous gene overexpression in tumors resistant to particular therapy types were also reviewed, but only in such cases where the abolition of overexpression of a particular gene led to the abolition of the changed phenotype. ...
Reactive oxygen species (ROS) are normal products of a number of biochemical reactions and are important signaling molecules. However, at the same time, they are toxic to cells and have to be strictly regulated by their antioxidant systems. The etiology and pathogenesis of many diseases are associated with increased ROS levels, and many external stress factors directly or indirectly cause oxidative stress in cells. Within this context, the overexpression of genes encoding the proteins in antioxidant systems seems to have become a viable approach to decrease the oxidative stress caused by pathological conditions and to increase cellular stress resistance. However, such manipulations unavoidably lead to side effects, the most dangerous of which is an increased probability of healthy tissue malignization or increased tumor aggression. The aims of the present review were to collect and systematize the results of studies devoted to the effects resulting from the overexpression of antioxidant system genes on stress resistance and carcinogenesis in vitro and in vivo. In most cases, the overexpression of these genes was shown to increase cell and organism resistances to factors that induce oxidative and genotoxic stress but to also have different effects on cancer initiation and promotion. The last fact greatly limits perspectives of such manipulations in practice. The overexpression of GPX3 and SOD3 encoding secreted proteins seems to be the “safest” among the genes that can increase cell resistance to oxidative stress. High efficiency and safety potential can also be found for SOD2 overexpression in combinations with GPX1 or CAT and for similar combinations that lead to no significant changes in H2O2 levels. Accumulation, systematization, and the integral analysis of data on antioxidant gene overexpression effects can help to develop approaches for practical uses in biomedical and agricultural areas. Additionally, a number of factors such as genetic and functional context, cell and tissue type, differences in the
function of transcripts of one and the same gene, regulatory interactions, and additional functions should be taken into account.
... TXNRD1 inhibition can lead to an impairment of required antioxidant capacity particularly in cancer cells, while normal cells can survive a loss of TXNRD1 activity, it is thus not far-fetched to propose that TXNRD1 inhibition may be a potential mechanism of action for anticancer drugs [17]. Previous studies have revealed that overexpression of TXNRD1 modulates drug-specific cytotoxic responses [18] and inhibition of the TXNRD1 enhances the efficacy of some chemotherapeutics, such as improving ibrutinib's anti-EGFR activity in lung cancer [19]. Moreover, high expression level of TXNRD1 has been reported in various cancers, such as breast, prostate and thyroid cancers, and is associated with aggressive tumor and poor prognosis [20][21][22][23]. ...
Thioredoxin reductase 1 (TXNRD1) is one of the major redox regulators in mammalian cells, which has been reported to be involved in tumorigenesis. However, its roles and regulatory mechanism underlying the progression of HCC remains poorly understood. In this study, we demonstrated that TXNRD1 was significantly upregulated in HCC tumor tissues and correlated with poor survival in HCC patients. Functional studies indicated TXNRD1 knockdown substantially suppressed HCC cell proliferation and metastasis both in vitro and in vivo, and its overexpression showed opposite effects. Mechanistically, TXNRD1 attenuated the interaction between Trx1 and PTEN which resulting in acceleration of PTEN degradation, thereby activated Akt/mTOR signaling and its target genes which conferred to elevated HCC cell mobility and metastasis. Moreover, USF2 was identified as a transcriptional suppressor of TXNRD1, which directly interacted with two E-box sites in TXNRD1 promoter. USF2 functioned as tumor suppressor through the downstream repression of TXNRD1. Further clinical data revealed negative co-expression correlations between USF2 and TXNRD1. In conclusion, our findings reveal that USF2-mediated upregulation of TXNRD1 contributes to hepatocellular carcinoma progression by activating Akt/mTOR signaling.
... Previous studies highlighted that inhibition of TrxR by "single-acting" small molecules yielded ineffective changes in cancer cell proliferation and spreading, suggesting that a "multi-acting" system approach is needed to circumvent the inherent compensatory redundancy. [34,35] Consistently, multiacting gold(I) anticancer agents developed so far showed an outstanding anticancer profile, attesting that the conjugation of different pharmacophores within the same molecular entity allows to simultaneously deliver multiple bioactive molecules into cancer cells, thus boosting the neat anti-proliferative potential of the resulting compound. [36] On this basis, the antitumor potential of the reported NHC-based selenoureas and their Au(I) and Ag(I) related metal complexes was assayed in vitro, on 2D and 3D cancer cell systems. ...
A series of NHC‐based selenourea Ag(I) and Au(I) complexes were evaluated for their anticancer potential in vitro, on 2D and 3D human cancer cell systems. All NHC‐based selenourea complexes possess an outstanding cytotoxic potency, which was comparable or even better than that of the reference metallodrug auranofin, and were also able to overcome both platinum‐based and multi‐drug resistances. Intriguingly, their cytotoxic potency did not correlate with solution stability, partition coefficient or cellular uptake. On the other hand, mechanistic studies in cancer cells revealed their ability to strongly and selectively inhibit the redox‐regulating enzyme Thioredoxin Reductase (TrxR), being even more effective than auranofin, a well‐known TrxR inhibitor, without affecting other redox enzymes such as Glutathione Reductase (GR). The inhibition of TrxR in H157 human cancer cells caused, in turn, the disruption of cellular thiol‐redox homeostasis and of mitochondria pathophysiology, ultimately leading to cancer cell death through apoptosis.
