Search Results (3,318)

Since 2014, a model of the individual response to ionizing radiation (IR), based on the radiation-induced nucleoshuttling of the ATM protein kinase (RIANS), has been developed by our lab: after irradiation, ATM dimers monomerize in cytoplasm and diffuse into the nucleus to trigger both recognition and repair of DNA double-strand breaks (DSB), the key-damage of IR response. Moderate radiosensitivity is generally caused by heterozygous mutations of ATM substrates (called X-proteins) that are over-expressed in cytoplasm and form complexes with ATM monomers, which reduces and/or delays the RIANS and DSB recognition. Here, we asked whether molecules, rather than X-proteins, can also influence RIANS. Caffeine was chosen as a potential “X-molecule” candidate. After incubation of cells with caffeine, cutaneous fibroblasts from an apparently healthy radioresistant donor, a patient suffering from Alzheimer’s disease (AD) and another suffering from neurofibromatosis type 1 (NF1) were exposed to X-rays. The functionality of ATM-dependent DSB repair and signaling was evaluated. We report here that caffeine molecule interaction with ATM leads to the inhibition of DSB recognition. This effect is significant in radioresistant cells. Conversely, in the AD and NF1 cells, the DSB recognition is already so low that caffeine does not provide any additional molecular effect. Full article

Background/Objectives: Octenidine dihydrochloride (OCT-D) is a broad-spectrum antiseptic with high chemical stability, low toxicity, and no reported microbial resistance, making it a strong candidate for use on mucosal surfaces. Despite increasing interest in its potential ophthalmic applications, limited data exist regarding its cellular effects on ocular tissues. This study aimed to investigate the cytotoxic, apoptotic, inflammatory, and transcriptional responses induced by OCT-D in human conjunctival (IOBA-NHC) and retinal pigment epithelial (ARPE-19) cells. Methods: Cells were exposed to varying concentrations of OCT-D, and viability was assessed using the WST-1 assay to determine IC₅₀ and IC₅₀/2 values. These concentrations were subsequently used in molecular assays. Pro-inflammatory cytokines (IL-6, IL-1β, TNF-α, IFN-γ) were quantified by ELISA. Apoptotic activation was evaluated through caspase-3/7 activity assays. Gene expression analysis of apoptotic (Bax, Bcl-2), DNA damage-related (ATM, Rad51), and inflammatory markers was performed using RT-qPCR. Results: OCT-D induced a marked, dose-dependent reduction in cell viability in both cell lines, with ARPE-19 showing greater sensitivity. Caspase-3/7 activity increased significantly at IC₅₀ and IC₅₀/2, confirming intrinsic apoptotic activation. OCT-D markedly suppressed the release of key inflammatory cytokines and downregulated transcription of inflammatory genes. RT-qPCR revealed upregulation of pro-apoptotic and DNA damage-associated genes, demonstrating coordinated activation of apoptotic and genomic stress pathways. Conclusion: OCT-D triggers integrated cytotoxic, apoptotic, and immunomodulatory responses in conjunctival and retinal epithelial cells. While these findings provide important mechanistic insights into OCT-D’s cellular effects, further studies using primary cells, advanced 3D ocular models, and disease-relevant systems are required to support its potential translational use in ophthalmology. Full article

Background/Objectives: Approved for treatment of acute leukemia, gemtuzumab ozogamicin (GO) and inotuzumab ozogamicin (InO) are antibody–drug conjugates (ADCs) that deliver a toxic calicheamicin (CLM) derivative. The resistance mechanisms to GO/InO remain incompletely understood. Methods: We performed a genome-wide clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 screen for CLM sensitivity genes, and then performed confirmatory cytotoxicity assays. Results: Several DNA damage pathway regulation genes were identified, most notably TP53. Across 13 acute leukemia cell lines, the six TP53-mutant cell lines (TP53^MUT) were indeed 10- to 1000-fold less sensitive to CLM than the seven TP53^WT cell lines. In five TP53^WT/KO syngeneic cell line pairs we generated, TP53^KO cells were significantly less sensitive to CLM than their TP53^WT counterparts. In TP53^WT but not TP53^MUT cells, the MDM2 inhibitor and p53 activator, idasanutlin, enhanced CLM cytotoxicity, demonstrating that decoupling of cells from MDM2-p53 regulation sensitizes leukemia cells to CLM. The ATM inhibitors AZD1390 and lartesertib also significantly enhanced CLM efficacy but did so independent of the TP53 status. In contrast, neither an ATR inhibitor, Chk1/Chk2 inhibitor, Chk2 inhibitor, or a PARP inhibitor significantly impacted CLM-induced cytotoxicity across the thirteen cell lines. Together, our studies identify ATM, MDM2, and TP53—which are in the same cellular response to DNA damage pathway—as key modulators of CLM-induced cytotoxicity in acute leukemia cells. Conclusions: These results support further evaluation of combination therapies with corresponding small-molecule inhibitors (currently pursued for therapy of other cancers) toward clinical testing as novel strategies to increase the efficacy of CLM-based ADCs such as GO and InO. Full article

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by autoantibody production and the formation of immune complexes (ICs), which lead to widespread inflammation and tissue damage. Neutrophil extracellular traps (NETs), web-like structures composed of DNA, histones, and antimicrobial proteins released by activated neutrophils, play a crucial role in innate immunity by defending against pathogens. However, excessive NET formation and ineffective clearance of these structures contribute to the development of SLE. This review explores the mechanisms behind NET formation in SLE, their relationship with oxidative stress, and the potential role of antioxidants in treatment. Research indicates that SLE patients exhibit two key abnormalities: excessive NET formation and impaired NET clearance. Excessive NET formation is driven by proinflammatory low-density granulocytes (LDGs) and immune complexes (ICs). Impaired NET clearance stems from reduced DNase1/DNase1L3 activity or anti-nuclease autoantibodies. These two abnormalities lead to elevated circulating NETs. These NETs act as autoantigen reservoirs, forming pathogenic NET–ICs that amplify autoimmune responses. Oxidative stress drives NET formation by activating NADPH oxidase. In contrast, various antioxidants, including enzymatic and non-enzymatic types, can inhibit NET formation via scavenging reactive oxygen species (ROS) and blocking NADPH oxidase activation. Preclinical studies show that antioxidants such as curcumin, resveratrol, and mitochondrial-targeted MitoQ reduce NET formation and ameliorate lupus nephritis; clinical trials confirm that curcumin and N-acetylcysteine (NAC) lower SLE disease activity and reduce proteinuria, supporting their role as safe adjuvant therapies. However, high-dose vitamin E may exacerbate autoimmunity, highlighting the need for dose optimization. Future research should aim to clarify the mechanisms underlying NET formation in SLE and to optimize new antioxidant therapies, including assessments of their long-term efficacy and safety. Full article

Zinc oxide nanoparticles (ZnO NPs) are increasingly applied in medicine, cosmetics, and environmental technologies, yet their interactions with blood cells remain poorly understood, raising cross-species safety concerns. Using frog (nucleated) and human (anucleate) erythrocytes as comparative models, we show that cellular architecture fundamentally shapes responses to ZnO NPs exposure. Human erythrocytes exhibited a dose-dependent progression from membrane deformation to eryptosis and hemolysis, reflecting the pronounced vulnerability of anucleate cells. In contrast, frog erythrocytes sustained nuclear DNA damage while largely preserving membrane integrity, highlighting the protective or reparative role of the nucleus. Molecular docking revealed energetically favorable interactions of ZnO NPs with ERα-LBD and DNA (ΔG = −4.28 and −5.68 kcal/mol, respectively), while quantum chemical analyses indicated electron-accepting properties and a narrow HOMO–LUMO gap, suggesting efficient macromolecular interactions and intracellular ROS generation. Together, these findings demonstrate that the presence of a nucleus shifts the primary target of nanoparticle toxicity from membrane to genome, providing novel mechanistic insights. This comparative study offers a robust framework for understanding nanomaterial reactivity across taxa and informs One Health-oriented risk assessments. Full article

Polystyrene nanoplastics (PS-NPs) can cross the placenta and blood–brain barrier to accumulate in the fetal brain following inhalation or ingestion, raising concerns about PS-NPs-induced developmental neurotoxicity (DNT). However, current evidence regarding the mechanisms underlying PS-NPs-elicited DNT remains critically scarce. Given the inherent limitations of two-dimensional cell culture techniques, we employed a whole-brain organoid (WBO) model, which more faithfully recapitulates the dynamic changes and substantial alterations during the early development of the human nervous system, to investigate the PS-NPs-induced DNT. Developing WBOs were exposed to 50-nm PS-NPs at concentrations of 50 and 100 μg/mL. Additionally, we established an early developmental exposure model in neonatal rat for robust validation. The results revealed aberrant formation of the tissue architecture of neural epithelial buds in PS-NPs-exposed WBOs, accompanied by significant inflammatory responses and oxidative stress. Marked DNA damage and substantial activation of the TLR9/MyD88 pathway were observed in WBOs and in the cerebral cortex of neonatal rat, leading to significant upregulation of the excitotoxicity marker c-Fos and the excitatory synaptic marker NMDAR. In vitro assays revealed that melatonin treatment could efficiently counteract PS-NPs-mediated neuronal impairment, with both the reduced cell viability and excessive DNA damage induced by PS-NPs being restored to levels close to those of the control group. In conclusion, by establishing WBOs and early developmental exposure models in neonatal rat, we found that PS-NPs can induce DNA double-strand breaks, and activation of the TLR9 pathway mediates PS-NPs-induced excitotoxicity. Full article

Uterine Fibroids (UFs) are the most common benign tumors in women of reproductive age, affecting ~77% of women overall and are clinically manifest in ~25% by age 50. Bromodomain and extra-terminal domain (BET) proteins play key roles in epigenetic transcriptional regulation, influencing many biological processes, such as proliferation, differentiation, and DNA damage response. Although BET dysregulation contributes to various diseases, their specific role in the pathogenesis of UFs remains largely unexplored. The present study aimed to determine the expression pattern of BET proteins in UFs and matched myometrium and further assess the impact of BET inhibitors on UF phenotype and epigenetic changes. Our studies demonstrated that the levels of Bromodomain-containing protein (BRD)2 and detection rate of BRD4 were significantly altered in UFs compared to matched myometrium, suggesting that aberrant BET protein expression may contribute to the pathogenesis of UFs. To investigate the biological effects of BET proteins, two small-molecule inhibitors, JQ1 and I-BET762, were used to assess their impact on UF cell behavior and transcriptomic profiles. Targeted inhibition of BET proteins markedly reduced UF cell viability compared with myometrial cells and induced cell cycle arrest. Unbiased transcriptomic profiling coupled with bioinformatic analysis revealed that BET inhibition altered multiple biological pathways, including G2M checkpoint, E2F targets, mitotic spindle, mTORC1 signaling, TNF-α signaling via NF-κB, and inflammatory response, as well as reprogrammed the UF cell epigenome. Notably, BET inhibition decreased the expression of several genes encoding extracellular matrix (ECM) proteins, a hallmark of UFs. Collectively, these results support that BET proteins play a pivotal role in regulating key signaling pathways and cellular processes in UFs. Targeting BET proteins may therefore represent a promising non-hormonal therapeutic strategy for UF treatment. Full article

Cellular senescence is defined as a state of permanent cell cycle arrest, providing a natural barrier against cancer. However, senescent cells are very metabolically active and secrete a complex mixture of bioactive molecules collectively known as the senescence-associated secretory phenotype (SASP), which play a dual role in cancer biology. While the SASP can suppress tumors by facilitating immunosurveillance, it can also promote tumor progression by fostering a pro-inflammatory milieu, stimulating angiogenesis, enhancing invasiveness, and enabling immune evasion. In Head and Neck Cancers (HNCs), a highly heterogeneous group of malignancies, SASP has emerged as a critical player in disease progression and treatment resistance. Persistent DNA damage response (DDR) signaling drives SASP and thereby contributes to the progression of head and neck cancer by modulating the tumour microenvironment. It influences the tumor microenvironment (TME) by facilitating epithelial-to-mesenchymal transition (EMT), promoting cancer stem cell-like properties, and impairing the efficacy of radiotherapy, chemotherapy, and immune checkpoint inhibitors. These effects underscore the need for targeted interventions to regulate SASP activity. This review presents a comprehensive overview of the molecular mechanisms underlying SASP generation and its effects on HNCs. We discuss the dual roles of SASP in tumor suppression and progression, its contribution to therapy resistance, and emerging therapeutic strategies, including novel senolytic and senomorphic drugs. Finally, we highlight key challenges and future directions for translating SASP-targeted therapies into clinical practice, emphasizing the need for biomarker discovery, and a deeper understanding of SASP heterogeneity. By targeting the SASP, there is potential to enhance therapeutic outcomes and improve the management of HNCs. Full article

Nuclear factor erythroid 2-related factor 2 (NRF2) orchestrates redox balance, metabolism, and cellular stress responses, acting as both a tumor suppressor and promoter depending on the disease stage. In advanced cancers, persistent NRF2 activation—through KEAP1/NFE2L2 mutations or oxidative adaptation—drives epithelial-to-mesenchymal transition, metabolic reprogramming, and immune evasion, promoting tumor invasion (T) and metastasis (M). Recent pharmacologic efforts seek to exploit this duality. NRF2 inhibitors such as brusatol, halofuginone, and ML385 suppress NRF2 transcriptional activity or disrupt DNA binding, reducing motility, invasion, and metastatic dissemination in preclinical models. In contrast, NRF2 activators, such as bardoxolone methyl (CDDO-Me), sulforaphane, and dimethyl fumarate, exhibit chemopreventive effects by enhancing detoxification and mitigating oxidative DNA damage during early tumorigenesis. Furthermore, metabolic interventions, such as glutaminase or G6PD inhibitors, target NRF2-driven anabolic and antioxidant pathways essential for metastatic fitness. Therefore, understanding the temporal and contextual effects of NRF2 signaling is crucial for therapeutic design. The aim of this review is to examine how pharmacological modulation of NRF2 influences the invasive and metastatic dimensions of tumor progression, in addition to discussing its potential integration into TNM-based prognostic and treatment frameworks. Full article

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related mortality, with therapeutic resistance continuing to limit long-term responses. Among emerging resistance mechanisms, dysregulation of nucleocytoplasmic transport has gained attention for its ability to inactivate tumor suppressor pathways. Exportin 1 (XPO1), the primary nuclear export protein, is frequently overexpressed in NSCLC and promotes the cytoplasmic mislocalization of proteins involved in cell cycle control, apoptosis, and DNA repair. This includes key regulators such as p53, FOXO, and RB, whose inactivation supports tumor progression and therapy resistance. Inhibition of XPO1 with selective inhibitors of nuclear export (SINE) compounds, including selinexor, has demonstrated the ability to restore nuclear localization and function of these proteins, thereby enhancing cellular sensitivity to DNA-damaging agents, kinase inhibitors, and immunotherapies. In preclinical NSCLC models, XPO1 inhibition has shown efficacy both as monotherapy and in combination strategies, with particular promise in KRAS- and EGFR-driven tumors. This review explores the role of XPO1 in NSCLC biology and therapy resistance, the rationale for targeting nuclear export, and the current landscape of XPO1-directed clinical development in lung cancer. Full article

Cancer therapy resistance emerges from highly integrated molecular systems that enable tumor cells to evade cell death and survive cytotoxic therapeutic stress. High Mobility Group Box 1 (HMGB1) is increasingly gaining recognition as a central coordinator of these resistance programs. This review delineates how HMGB1 functions as a molecular switch that dynamically redistributes between cellular compartments in response to stress, with each localization enabling a distinct layer of resistance. In the nucleus, HMGB1 enhances chromatin accessibility and facilitates the recruitment of DNA repair machinery, strengthening resistance to radio- and chemotherapeutic damage. Cytosolic HMGB1 drives pro-survival autophagy, maintains redox stability, and modulates multiple regulated cell death pathways, including apoptosis, ferroptosis, and necroptosis, thereby predominantly shifting cell-fate decisions toward survival under therapeutic pressure. Once released into the extracellular space, HMGB1 acts as a damage-associated molecular pattern (DAMP) that activates key pro-survival and inflammatory signaling pathways, establishing microenvironmental circuits that reinforce malignant progression and therapy escape. HMGB1 further intensifies resistance through upregulation of multidrug resistance transporters, amplifying drug efflux. Together, these compartmentalized functions position HMGB1 as a central node in the networks of cancer therapy resistance. Emerging HMGB1-targeted agents, ranging from peptides and small molecules to receptor antagonists and nanoformulations, show promise in reversing resistance, but clinical translation will require precise, context- and redox-informed HMGB1 targeting to overcome multifactorial resistance program in refractory cancers. Full article

Proline-, glutamic acid-, and leucine-rich protein 1 (PELP1) is a proto-oncogene that serves as a nuclear and cytoplasmic scaffolding protein. PELP1 plays a critical role in nuclear receptor signaling, ribosome biogenesis, chromatin modifications, cell cycle progression, non-genomic signaling, and DNA damage response. PELP1 expression is upregulated in a variety of cancers, including breast, ovarian, endometrial, prostate, and liver cancers and serves as a prognostic factor for poor survival. PELP1’s structural motifs, unique scaffolding function, and oncogenic activity make it a potential target for a range of therapeutic approaches. This review summarizes the most recent advancements in PELP1 biology, with a particular focus on the emergent oncogenic functions of PELP1 and its inhibitors for the treatment of cancer. Full article

Computed tomography (CT) is a major source of low-dose ionizing radiation exposure in medical imaging. Risk assessment at this dose level is difficult and relies on the hypothetical linear no-threshold model. To address the response to such low doses in patients undergoing CT scans, we examined radiation-induced alterations at the transcriptomic and DNA damage levels in peripheral blood cells. Peripheral whole blood of 60 patients was collected before and after CT. Post-CT samples were obtained 4–6 h after scan (n = 28, in vivo incubation) or alternatively immediately after the CT scan, followed by ex vivo incubation (n = 32). The gene expression of known radiation-responsive genes (n = 9) was quantified using qRT-PCR. DNA double-strand breaks (DSB) were assessed in 12 patients through microscopic γ-H2AX + 53BP1 DSB focus staining. The mean dose–length product (DLP) across all scans was 561.9 ± 384.6 mGy·cm. Significant differences in the median differential gene expression (DGE) were detected between in vivo and ex vivo incubation conditions, implicating that ex vivo incubation masked the true effect in low-dose settings. The median DGE of in vivo-incubated samples showed a significant upregulation of EDA2R, MIR34AHG, PHLDA3, DDB2, FDXR, and AEN (p ranging from <0.001 to 0.041). In vivo, we observed a linear dose-dependent upregulation for several genes and an explained variance of 0.66 and 0.56 for AEN and FDXR, respectively. DSB focus analysis revealed a slight, non-significant increase in the average DSB damage post-exposure, at a mean DLP of 321.0 mGy·cm. Our findings demonstrate that transcriptional biomarkers are sensitive indicators of low-dose radiation exposure in medical imaging and could prove themselves as clinically applicable biodosimetry tools. Furthermore, the results underscore the need for dose optimization. Full article

Mitochondrial dysfunction is a pivotal contributor to neurodegeneration. Neurons heavily rely on mitochondrial oxidative metabolism and therefore need highly efficient quality control mechanisms, including proteostasis, mitochondrial biogenesis, fusion–fission dynamics, and mitophagy, to sustain bioenergetics and synaptic function. With aging, deterioration of mitochondrial quality control pathways leads to impaired oxidative phosphorylation, excessive reactive oxygen species generation, calcium imbalance, and defective clearance of damaged organelles, ultimately compromising neuronal viability. Pathological protein aggregates, such as α-synuclein in Parkinson’s disease, β-amyloid and tau in Alzheimer’s disease, and misfolded superoxide dismutase 1 and transactive response DNA-binding protein 43 in amyotrophic lateral sclerosis, further aggravate mitochondrial stress, establishing self-perpetuating cycles of neurotoxicity. Such mitochondrial defects underscore mitochondria as a convergent pathogenic hub and a promising therapeutic target for neuroprotection. Intermediate filaments (IFs), traditionally viewed as passive structural elements, have recently gained attention for their roles in cytoplasmic organization, mitochondrial positioning, and energy regulation. Emerging evidence indicates that IF–mitochondria interactions critically influence organelle morphology and function in neurons. This review highlights the multifaceted involvement of mitochondrial dysfunction and IF dynamics in neurodegeneration, emphasizing their potential as targets for novel therapeutic strategies. Full article

Renal Cell Carcinoma (RCC) is a common malignancy, often diagnosed incidentally. In recent years, the prognosis of metastatic disease has been improved due to the development of immune checkpoint inhibitors (ICI) and tyrosine kinase inhibitors (TKI) as first-line treatments. However, when progression occurs, the therapeutic options are limited. Understanding crucial biological pathways could lead to a greater understanding of the natural history of the disease, which could help to overcome the mechanism of resistance and to develop new treatments. The clinical significance of homologous recombination deficiency (HRD) in RCC remains to be investigated. To improve the knowledge about this topic, we conducted a narrative review to summarize the current evidence on HRD-related variations and signatures in RCC, together with their prognostic and predictive implications. Preliminary evidence indicates that canonical HRD variants (BRCA1/2) are infrequent in RCC, while broader DNA damage response (DDR) alterations like BAP1, PBRM1, ATM, and SETD2 are more prevalent. Elevated HRD genomic scores in clear-cell RCC correlate with a worse prognosis and an immunologically exhausted microenvironment. From a therapeutic point of view, PARP inhibitor monotherapy has exhibited initial efficacy in small cohorts with high levels of DDR mutation, yet remains investigational for RCC. Full article