Search Results (758)

Background/Objectives: The tumor microenvironment (TME) plays a crucial role in the progression of the malignant phenotype through several mechanisms, such as hypoxia and nutrient deprivation, among others. These insults activate several intracellular pathways, and among them are ER stress and the unfolded protein response (UPR). Our aim was to assess if a specific ER stress inducer causes an exacerbation of the malignant phenotype of anaplastic thyroid carcinoma (ATC) cells. Methods: We used an ATC cell line, FRO cells, that had not undergone a full Epithelial–Mesenchymal Transition (EMT) and an ER stress-adapted cell line derived from FRO cells, A400 cells. Western blot, immunofluorescence, scratch, and invasion assays were used to evaluate the response of the FRO and A400 cells to ER stress. Results: The FRO cells were subjected to high-level ER stress caused by400 ng/mL of tunicamycin (Tn). This caused the death of a large fraction of cells, but eventually a population emerged that we called A400 cells. Following an over challenge with Tn, the adapted population showed suppression of the UPR, apoptosis, and stress kinase activation. Moreover, the adapted population showed an exacerbation of mesenchymal features with a more invasive phenotype. At the level of a single cell, the adapted cells, caught in the act of moving, showed high-level expressions of vimentin (VIM), fibronectin (FN), and N-cadherin. Conclusion: High-level ER stress acts as a selection factor favoring the emergence of a cell population showing “mesenchymal drift” with a more malignant phenotype. Full article

Previous studies have demonstrated that high-yielding dairy cows experience endoplasmic reticulum (ER) stress in the liver during early lactation. To date, most insights into the role of ER stress in metabolism and disease pathophysiology have been derived from rodent and human models. In dairy cattle, however, the specific impact of ER stress on metabolic pathways and its contribution to disease development remain insufficiently characterized. The objective of this study was therefore to investigate the molecular effects of ER stress using a bovine liver cell model (BFH12 cells). ER stress was induced by incubation with Tunicamycin (TM) and Thapsigargin (TG). Molecular responses to ER stress were assessed via a whole-genome array analysis and PCR targeting genes involved in selected metabolic pathways. Incubation with both ER stress inducers resulted in a marked upregulation of genes associated with the unfolded protein response (UPR) within a 4 to 24-h time frame, indicative of the production of robust ER stress in these cells. Unexpectedly, treatment with TM led to a downregulation of numerous genes involved in lipid biosynthesis, including those related to lipogenesis and cholesterol synthesis. Furthermore, incubation with TM and TG induced upregulation of genes involved in fatty acid oxidation and was accompanied by a reduction in intracellular triglyceride concentrations. Genes associated with inflammatory responses were upregulated by both TM and TG, whereas genes encoding antioxidant enzymes were downregulated. Genes involved in ketogenesis did not exhibit a consistent pattern of regulation. Overall, several effects of ER stress previously described in rodent models could not be replicated in this bovine liver cell system. Extrapolating these findings to dairy cows suggests that while ER stress may contribute to hepatic inflammation, it is unlikely to play a significant role in the development of hepatic lipidosis or ketosis. Full article

Sarcomas are a rare and heterogeneous group of malignant tumors that pose significant clinical challenges, including delayed diagnosis, therapeutic resistance, and lack of reliable biomarkers. Despite advances in surgery and chemotherapy, effective treatment options for advanced disease remain limited, underscoring the urgent need to identify novel therapeutic vulnerabilities. The unfolded protein response (UPR), a conserved cellular stress pathway that maintains proteostasis under conditions of endoplasmic reticulum stress, has emerged as a critical modulator of cancer cell fate. By regulating protein folding, redox balance, and survival pathways, the UPR exerts a dual role in tumor biology, supporting tumor growth under stress while triggering apoptosis when stress becomes sustained or severe. In sarcomas, accumulating evidence indicates that UPR activation contributes to metabolic adaptation, angiogenesis, immune evasion, and chemoresistance. Drawing on the current literature encompassing preclinical models, recent translational research (PubMed from 2000 to 2025), and registered clinical trials, this narrative review synthesizes current knowledge on the multifaceted role of the UPR in sarcoma pathogenesis, with a particular focus on osteosarcoma. Furthermore, it explores the feasibility of UPR-targeted strategies as adjuvant or combinatorial approaches. In conclusion, this review provides an integrated and in-depth analysis of UPR-mediated mechanisms in sarcomas, offering perspectives on how targeting this pathway could accelerate the development of more effective and personalized treatments. Full article

Background: Permanent cancer resolution requires a complete immunological response with generation of memory against malignant cells. Immunogenic cell death (ICD) achieves this by coupling cell death with the emission of damage-associated molecular patterns (DAMPs). Current cancer treatments immunosuppress the host; thus, new alternatives are needed. Ganoderma species produce anticancer triterpenoids (GTs); however, their mechanism remains unclear. Objective: This systematic review aims to provide insights into GTs’ pharmacodynamics and assess hypothetical ICD potential. Methods: Web of Science and PubMed databases were consulted following PRISMA guidelines. Studies from inception until 2024, reporting molecular changes associated with GTs’ anticancer effects, were considered. Nonhuman models were excluded. GTs and GTs-ICD converging molecular targets were listed and submitted to Cytoscape’s stringApp to construct protein interaction networks. Topological and enrichment analysis were performed. Results: A total of 204 articles were found, and 69 remained after screening. Overall anticancer effects include loss of mitochondrial membrane potential, DNA and RNA damage, autophagy, cell cycle arrest, and leukocyte activation. 136 molecular targets of GTs were identified; upregulated proteins include CHOP, PERK, p-eIF2α, and HSP70, a key DAMP. GTs and ICD share 24 molecular targets. GO:BP and KEGG enrichment analysis suggest that GTs’ anticancer effects are related to stress response, cell death regulation, and PD-L1/PD-1 checkpoint inhibition. GT-ICD enrichment converges on endoplasmic reticulum stress, unfolded protein response, and organelle membrane perforation. Conclusions: GTs exhibit polypharmacological anticancer effects, including anti-immunosuppression, upregulation of ICD-adjacent machinery, and even an increase in HSP. However, further studies are required to confirm a proper causal link between GTs’ cancer cell treatment and DAMP emission. Full article

Gaucher disease (GD) is an autosomal recessive metabolic disorder caused by pathogenic variants in the GBA1 gene, which encodes the lysosomal hydrolase β-glucocerebrosidase (GCase). The pathogenic defects result in a misfolded protein, which can trigger endoplasmic reticulum stress and an unfolded protein response within the affected cells. The reduced enzyme activity leads to accumulation of its substrates, glucosylceramide (GlcCer) and glucosylsphingosine (GlcSph), within lysosomes or macrophages and with prominent disease manifestations in reticuloendothelial tissues such as liver, spleen and bone marrow. GCase defects alter both the mitochondria and the lysosome. In the lysosome, reduced GCase activity leads to glycosphingolipid build-up, disrupting lysosomal function and autophagy, thereby activating α-synuclein accumulation. GCase can also be imported into the mitochondria, where it fosters the integrity and function of mitochondrial respiratory chain (MRC) complex I. Thus, the reduced GCase activity impairs the normal mitochondrial function and increases oxidative stress in this organelle, which may contribute to cell death. However, further studies are required to confirm this mechanism of MRC dysfunction. In this review we have systematically evaluated the evidence for oxidative stress in individuals affected by GD, as well as the currently available therapies and adjunctive therapies. Therapies targeting oxidative stress may prove useful as adjuvant treatments for GD. Full article

Chemical disinfection of removable acrylic dental prostheses minimizes the risk of denture stomatitis caused by the opportunistic fungal pathogen Candida albicans. We previously reported that neutral-pH electrolysed oxidising water (EOW), a hypochlorous acid (HOCl)-based biocide, is effective at inhibiting C. albicans biofilm formation on denture resins. Knowledge about the mechanism of action of EOW on C. albicans is lacking. This study investigated the molecular mechanism of action of neutral-pH EOW against C. albicans cells that were incubated with sub-inhibitory concentrations of EOW-HOCl (treatment with 0.125× MIC₉₀ EOW-HOCl (15 µM; T0.125) or treatment with 0.5× MIC₉₀ EOW-HOCl (59 µM; T0.5)). RNA-sequencing (RNA-seq) was used to identify differentially expressed genes (DEGs) which were validated by qRT-PCR. Ninety-five DEGs were identified between the treated and untreated cells after a 60 min exposure. A moderate sub-inhibitory EOW-HOCl concentration (T0.125) caused significant upregulation (log₂ fold change > +2) of genes responsive to oxidative stress (EBP1, GAP6, PRN1, HSP21), weak organic acid stress (PRN1), and heat-shock (HSP21). A higher sub-inhibitory concentration (T0.5) caused a significant downregulation of most DEGs (notably, −1.9 to −3 log₂ fold reduction in SUT1, HNM3, STP4 expression), cessation of growth, and an upregulation of genes involved in ammonia transport, carbohydrate metabolism, and the unfolded protein and apoptotic response pathways (ATO2, IRE1). Our findings reveal HSP21 and PRN1 to be possible key players in protecting C. albicans cells against HOCl, a natural biocide of the innate immune system. Full article

Tempol, a synthetic nitroxide, exhibits dual antioxidant and pro-oxidant activity, requiring millimolar concentrations to induce oxidative stress, which limits its therapeutic use. Glutathione Peroxidase 4 (GPX4) is a critical lipid peroxidase that prevents ferroptosis, and its inhibition has emerged as a strategy to sensitize cancer cells to oxidative stress. To enhance Tempol’s efficacy, we investigated its interaction with ML210, a GPX4 inhibitor, in human colon (HT29) and gastric (CRL-1739) cancer cell lines. We quantified cell viability, oxidative stress markers (H₂O₂, Total Oxidant Status (TOS), and Total Antioxidant Status (TAS)) and endoplasmic reticulum (ER) stress proteins (ATF6, GRP78, and IRE1α) in in vitro assays. Synergy was assessed using Bliss independence analysis. The combination of Tempol (2 mM) and ML210 (0.05 μM) markedly reduced viability in both cell lines. Bliss analysis revealed slight/moderate synergy for cytotoxicity (Δ = +0.15 in HT29; Δ = +0.26 in CRL-1739) and strong synergy for H₂O₂ accumulation (Δ = +1.92–2.23 across replicates). In contrast, TOS showed moderate-to-strong antagonism across both cell lines, and TAS demonstrated slight synergistic or antagonistic effects. ER stress markers exhibited marker and cell line specific synergy: ATF6 showed strong synergy, IRE1α slight synergy in both lines, and GRP78 activation was highly variable, showing strong synergy in CRL-1739 cells but moderate antagonism in HT29 cells. These findings indicate that the cooperative action of Tempol and ML210 is ROS-pool–specific and pathway-selective in the ER. These findings demonstrate that ML210 potentiates Tempol’s pro-oxidant pressure by targeting GPX4, selectively amplifying H₂O₂ accumulation and ER stress engagement without collapsing global redox balance. This study provides mechanistic rationale for redox–proteostasis co-targeting in gastric and colon cancers and establishes a foundation for in vivo validation. Full article

Pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED) are rare, autosomal dominant skeletal dysplasias characterised by disproportionate short stature, joint deformities, and early-onset osteoarthritis. These conditions result from mutations in key cartilage extracellular matrix (ECM) components, including cartilage oligomeric matrix protein (COMP), matrilin-3, and type IX collagen. Although genetically and clinically heterogeneous, PSACH and MED share convergent pathogenic mechanisms. Misfolded mutant ECM proteins are retained within the endoplasmic reticulum (ER) of growth plate chondrocytes, triggering chronic ER stress and impairing chondrocyte proliferation, differentiation, and survival. Moreover, some of the mutant protein is secreted and incorporated into the matrix, leading to altered collagen fibrillogenesis, disrupted proteoglycan distribution, and compromised biomechanical integrity. These alterations extend beyond cartilage, impacting tendons, ligaments, and muscle–tendon junctions, contributing to joint laxity, impaired force transmission, and mild myopathy. This review discusses the structural and functional consequences of ECM disorganisation in PSACH and MED, highlighting its central role in disease progression and emphasising the importance of considering ECM abnormalities when developing therapeutic strategies for rare short stature-associated skeletal disorders. Full article

Under global warming, drought frequency and its severity have risen notably, posing considerable challenges to vegetation growth. Central Asia (CA), recognized as the largest non-zonal arid zone globally, features dryland ecosystems that are particularly vulnerable to drought stress. This research examines how plant life in CA reacts to prolonged dry spells by analyzing multiple datasets, including drought indices and satellite-derived NDVI measurements, spanning four decades (1982–2022). This study also delves into the compound impact of drought, revealing how its influence on vegetation unfolds through both cumulative stress and delayed ecological responses. Based on the research results, the vegetation coverage in CA exhibited a notable rising tendency from 1982 to 1998. Specifically, it increased at a rate of 4 × 10⁻³ per year (p < 0.05). On the other hand, the direction of this trend shifted to a downward one during the period from 1999 to 2022. During this latter phase, the vegetation coverage decreased at a rate of −4 × 10⁻³ per year (p > 0.05). Vegetation changes in the study area underwent a fundamental reversal around 1998, shifting from widespread greening during 1982–1998 to persistent browning during 1999–2022. Specifically, 98.6% of the region underwent pronounced summer drought stress, which triggered a substantial rise in vegetation browning. The vegetation response to the accumulated and lagged effects of drought varied across seasons, with summer exhibiting the strongest sensitivity, followed by spring and autumn. The lagged effect of drought predominantly influences the vegetation during the growing season and spring, affecting 59.44% and 79.27% of CA, respectively. In contrast, the accumulated effect of drought is more prominent in summer and autumn, affecting 54.92% and 56.52% of CA. These insights offer valuable guidance for ecological restoration initiatives and sustainable management of dryland ecosystems. Full article

G-quadruplexes have been identified as a promising anti-cancer target because of their ability to modulate the stability of mRNAs encoding oncogenes, tumor suppressor genes, and other potential therapeutic targets. Deregulation of DNA damage and Unfolded Protein Response pathways in cancer cells may create vulnerabilities that can be exploited therapeutically. Previous studies have shown variations in the relative expression of DDR and UPR components in canine lymphoma and leukemia cell lines CLBL-1, CLB70, and GL-1. In the present study, we report the presence of G-quadruplex structures in these canine cell lines. Downregulation of the expression of DDR and UPR components at the mRNA level was observed in the CLBL-1 and CLB70 cell lines after stabilization of G4 structures using the ligand PhenDC3. In contrast, in GL-1 cells, important components of the DDR pathway, such as PARP1, GADD45A, and PIK3CB were upregulated in response to PhenDC3 treatment. Downregulation of DDIT4 mRNA expression, which encodes an important UPR component, was detected in the CLBL-1 and GL-1 cell lines after PhenDC3 exposure. These results suggest that G4 structures can be used to manipulate the expression of potential targets to treat lymphoma in dogs. A substantial enrichment of DNA replication and pyrimidine metabolism pathways was found in the GL-1 cell line after G4 stabilization. This finding suggests that PhenDC3 may induce DNA replication stress in this cell line. Collectively, these results support the feasibility of employing canine cancer cells as a model system to investigate the role of G-quadruplex structures in cancer. Full article

Background/Objective: Proteotoxic stress induced by inhibitors of the ubiquitin–proteasome system has been successful in multiple myeloma but not in solid cancers such as prostate cancer. Our objective is to find a combination with proteasome inhibitors that increases apoptotic cell death in all types of prostate cancer without harming non-cancer cells. Methods: The effectiveness of rencofilstat, a pan-cyclophilin inhibitor, combined with the ixazomib proteasome inhibitor, was investigated in multiple prostate cancer and non-cancer cells. Inducible knockdown of stress response XBP1s and cyclophilins A/B and inducible expression of XBP1s and cyclophilin B were developed in prostate cancer to determine functional roles. Results: Rencofilstat + ixazomib increased apoptotic cell death in prostate cancer but not in non-cancer cells. We investigated the effects on XBP1s and PERK, important unfolded protein response factors required for cells to survive proteotoxic stress. The results revealed that XBP1s had a pro-survival role early, but maintenance at later times of rencofilstat + ixazomib treatment resulted in cell death. In addition, decreased PERK and phospho-eIF2α likely maintained protein synthesis to further enhance proteotoxic stress. In contrast, rencofilstat + ixazomib did not alter XBP1s or PERK in non-cancer cells. Additional genetic experiments showed that the RCF targets cyclophilins A, B, and D had protective effects. Rencofilstat increased extracellular secretion of cyclophilin B, but rencofilstat + ixazomib reduced glycosylation and, likely, the biological function of CD147 (CypB receptor) and decreased downstream ERK signaling. Conclusions: Rencofilstat + ixazomib may be a new strategy for increasing proteotoxic stress and apoptotic cell death in advanced prostate cancer cells with less toxic side effects. Full article

Periodontal disease is a prevalent inflammatory disorder that can lead to severe oral complications. Recent studies increasingly underline the role of endoplasmic reticulum (ER) stress in its pathogenesis. Experimental models using inflammatory agents such as lipopolysaccharide (LPS), tumor necrosis factor-alpha (TNF-α), and ligature-induced periodontitis in rodents, as well as chemical hypoxia, have consistently demonstrated the activation of unfolded protein response (UPR) pathways in periodontal cells. Key ER stress markers, including CHOP, GRP78, PERK, and ATF6, were upregulated in periodontal ligament cells, stem cells, and gingival epithelial cells under these conditions. While ER stress in periodontitis is primarily associated with detrimental outcomes such as apoptosis and inflammation, it may also have a physiological role in bone remodeling via the PERK-eIF2α-ATF4 axis. Importantly, several ER stress-modulating agents—such as oridonin, melatonin, and exosomes derived from M2 macrophages—have shown therapeutic potential by reducing stress marker expression and limiting periodontal damage. These findings suggest that targeting ER stress may offer a novel therapeutic strategy. Future human studies are essential to determine whether a combined approach targeting inflammation and ER stress could more effectively halt or reverse periodontal tissue destruction, while also assessing the long-term safety of ER stress modulation. Full article

Endocrine cells are dedicated to the production and processing of hormones, from peptides to small molecules, to regulate key physiological processes, including glucose homeostasis and metabolism. Because of this relatively high productivity, endocrine cells must handle a variety of stresses from oxidative stress to the unfolded protein response of the endoplasmic reticulum (UPR^ER). While much is known about the major pathways regulating the UPR^ER, the roles of endocrine cell type-specific, context-dependent, and time-dependent transcriptional changes are not well explored. To identify unique and shared responses to the UPR^ER across a subset of endocrine cell types, we tested representative lines for β-cells (insulin), α-cells (glucagon), δ-cells (somatostatin), X/A-cells (ghrelin), L-cells (glucagon-like peptide 1 (GLP1)), and thyrotropes (thyroid hormone and thyroglobulin). We exposed each cell type to the canonical ER stressor thapsigargin for 6 and 24 h, or vehicle for 24 h, and performed mRNA sequencing. Analysis of the data showed all lines responded to thapsigargin. Comparisons of differentially expressed genes between each line revealed both shared and unique transcriptional signatures. These data represent a valuable mineable set of candidate genes that may have cell type-specific functions during the UPR^ER and have the potential to lead to a new understanding of how different endocrine cells mitigate or succumb to ER stress. Full article

The perturbation of ER homeostasis by viral infection gives rise to the unfolded protein response (UPR), characterized by the activation of three signaling pathways. PERK, IRE1, and ATF6 have been identified as the primary mediators responsible for restoring homeostasis or leading to apoptosis in response to stress. Alphaarterivirus equid, known as equine arteritis virus (EAV), is a RNA virus with importance in the equine industry that could persist in semen and lead to abortions in pregnant mares. The present article explores the consequences of in vitro infection with the EAV Bucyrus strain on UPR. Employing RT-PCR, qPCR and Western blot, our investigation has revealed the activation of PERK and IRE1α pathways, whilst ATF6 has been suppressed. Furthermore, the p38α MAPK, caspase-12, and CHOP genes were found to be upregulated, demonstrating the induction of apoptosis. Finally, in the inhibition experiments, the PERK pathway was found to be implicated in the modulation of viral replication in the initial phases of infection. Conversely, the IRE1α pathway was identified as the predominant UPR pathway in EAV replication, as evidenced by the complete inhibition of replication observed in these experiments. Consequently, the further exploration of this UPR pathway is necessary to determine whether it can effectively suppress EAV replication. Full article

Zika virus (ZIKV) can infect and replicate in the endoplasmic reticulum (ER) of different human cell types, including neural progenitor cells, radial glial cells, astrocytes, and microglia in the brain. ZIKV infection of microglia is expected to trigger both ER stress and the induction of an antiviral response through production of type-I interferons and pro-inflammatory cytokines, contributing to neuroinflammation during infection. Despite their critical role in ZIKV pathogenesis, the interplay between ER stress and the antiviral response during infection has not been fully characterized in human microglia. In this work, we show that infection of a human microglia cell line with ZIKV triggers the induction of an antiviral response and the activation of the endonuclease activity of the unfolded protein response sensor IRE1. Interestingly, we observed that both IRE1 and XBP1 were sequestered to the viral replication sites during infection. Moreover, pharmacological inhibition or hyperactivation of the endonuclease activity of IRE1 resulted in reduced viral titers. As such, while inhibition of IRE1 resulted in an increased type-I interferon response, hyperactivation led to a decrease in ZIKV RNA levels and the appearance of ER-derived cytoplasmic structures containing NS3, IRE1, and XBP1. Together, our data indicate that regulation of the endonuclease activity of IRE1 is critical for both ZIKV replication and immune activation, highlighting the potential of the ER stress sensor as a target for the development of antivirals to treat ZIKV infections. Full article