International Journal of Biological Sciences

Histone deacetylases (HDACs) are pivotal epigenetic regulators that modulate diverse cellular pathways by removing acetyl groups from lysine residues on both histone and non-histone proteins. Histone deacetylase 11 (HDAC11), the sole member of class IV HDACs, exhibits both deacetylation and fatty acid deacylation activities. Accumulating evidence implicates HDAC11 as a key epigenetic regulator of fundamental cellular processes, including metabolism, immune responses, and tissue development. Dysregulation of HDAC11 activity has been associated with inflammatory diseases, metabolic disorders, neurodegenerative conditions, and cancer, highlighting its potential as a therapeutic target. Although several HDAC11-specific inhibitors have been identified, none have progressed to clinical development. In this study, we aimed to discover HDAC11-selective inhibitors by integrating in silico and in vitro validation approaches. Homology modelling of the HDAC11 structure was conducted, followed by model validation, structure-based virtual screening, molecular dynamics (MD) simulations, and binding free energy calculations. We identified and validated three lead compounds and their intermediates using biochemical and cell-based assays. Fluorescence-based and HPLC-based enzymatic assays demonstrated potent inhibition of both the deacetylase and deacylase activities of HDAC11, with Inhibitor 6 and Inhibitor 3 exhibiting the strongest effects among the six compounds tested. Further, a decrease in lipid accumulation, reduced stability of the HDAC11 substrate SHMT2, as determined by immunoblot analysis and decreased cell viability, as assessed by MTT assay, confirmed HDAC11 inhibition in cellular models. The study shows that new HDAC11 inhibitors significantly reduce the viability of breast cancer cells and induce apoptosis; inhibitor 6, in particular, showed high potency, similar to the reference compound SIS-17. Flow cytometry showed that treated MDA-MB-231 cells exhibited cell-cycle arrest and increased apoptosis, a finding further confirmed by Annexin V/PI staining. Molecular analysis showed that BAX increased while BCL2 decreased, indicating that apoptotic pathways were activated in novel compound-treated MDA-MB-231 cells. The results suggest that inhibiting HDAC11 is an effective way to induce cancer cell death and provide a basis for further assessment of these compounds as potential treatments for breast cancer. Collectively, this study identifies novel zinc-chelating HDAC11 inhibitors containing a nitro-sp2 group, providing promising candidates for further therapeutic development.

A protein whose removal or deletion causes significant disruption or collapse of a protein-protein interaction (PPI) network is referred to as a vulnerable protein. Such proteins may serve as valuable therapeutic or diagnostic targets in disease-associated networks. In this study, two PPI networks were constructed, one for HPV-positive and the other for HPV-negative head and neck squamous cell carcinoma (HNSCC), and the vulnerable proteins of these networks were identified by the node deletion approach. After analyzing the networks, 27 unique vulnerable proteins in HPV-positive and 72 unique vulnerable proteins in HPV-negative HNSCC were identified. Among them, one HPV-positive and seven HPV-negative HNSCC vulnerable proteins were further chosen by integrating multi-omics data. To exploit the vulnerabilities of these proteins, candidate synthetic lethal (SL) partners were predicted whose inhibition may selectively impair tumor survival. Subsequently, drug-gene interaction analysis was performed to identify inhibitors targeting the SL partners of these vulnerable proteins. Notably, in HPV-positive HNSCC, TOP2A, CHEK1, and CHEK2 genes were identified as SL partners of TTN, and their inhibitors were already clinically approved. While in HPV-negative HNSCC, ADA and MMP19 were identified as an SL partner of LMO7; TMEM45B, CDH3, and ELF3 genes were identified as an SL partner of CGN; and ZNF433 was identified as an SL partner of FLNC. However, MMP19, ZNF433, and TMEM45B inhibitors were not reported. Thus, these vulnerable proteins, including their SL partners, provide novel avenues to explore and develop more efficient and precise therapeutic and diagnostic strategies.

Marine sponges are known sources of bioactive natural products (NPs), many of which are produced by associated bacterial symbionts via encoded biosynthetic gene clusters (BGCs). A particularly interesting subclass of sponge-derived NPs is comprised of small, brominated alkaloids, which are recovered from diverse habitats and host sponge taxonomies. Despite having been described decades ago, most of these NPs do not have an elucidated biosynthetic origin. We queried metagenomes of several sponge species by making use of a minimal set of core enzymes that we postulate to be necessary to produce these small peptidic NPs: an FADH2-dependent halogenase and an AMP-binding adenylation enzyme. This revealed a variety of novel BGC architectures, many of which showed conservation among sponge host phylogenies and were encoded in the genomes of diverse sponge-associated bacteria. Furthermore, we identified a BGC in the sponge G. barretti that is potentially linked to the production of the iconic barettins, given its enzymatic machinery and specific acidobacterial origin. The present work contributes to the challenging quest to link orphan brominated NPs to their parent BGCs in the sponge holobiont and beyond.

Viral infections have long been proposed as environmental contributors to neurodegenerative diseases, including Parkinson's disease (PD), yet the molecular mechanisms linking infection and neurodegeneration are not well defined. Neuroinflammation and disruption of central nervous system (CNS) homeostasis have emerged as potential mediators. In this study, we used severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, as a model pathogen to investigate convergent molecular pathways between viral infection and PD. Single-nucleus RNA sequencing (snRNA-seq) was performed on post-mortem striatal tissue from 14 individuals stratified into four groups: COVID-19 only (COVID-19), PD only (PD), comorbid PD with COVID-19 (PD/COVID-19), and controls (Control). The PD/COVID-19 group exhibited an expanded astrocytic population and a pronounced interferon-associated molecular signature characterized by increased expression of canonical interferon-stimulated genes, including IFI44L (average log2FC= 3.9; adjusted p=2.3 x 10-373), IFI44 (average log2FC=2.9; adjusted p=8.0 x 10-266), ISG15 (average log2FC=3.1; adjusted p=1.2 x 10-197), and RSAD2 (average log2FC= 3.5; adjusted p=8.6 x 10-111). Pathway analyses demonstrated activation of innate immune and antiviral signaling pathways, particularly within microglia and astrocytes, including interferon signaling, pattern-recognition receptor pathways, and complement-associated responses. In parallel, genes involved in lipid metabolism, cholesterol homeostasis, synaptic maintenance, and neuronal signaling were reduced across disease groups. Proteomic analyses independently confirmed enrichment of antiviral and interferon-associated pathways and identified convergent suppression of sterol, cholesterol, and lipid metabolic processes. Our findings identify a convergent molecular signature linking PD and COVID-19, pronounced in comorbid individuals and characterized by interferon-driven innate immune activation, glial inflammatory responses, and dysregulation of lipid metabolic homeostasis. Collectively, the data support a model in which severe viral infection amplifies biological pathways already implicated in PD pathogenesis.

Immune checkpoint blockade has revolutionized cancer therapy, but the therapeutic efficacy is limited. Clinical trials on blockade of newly identified immune checkpoints didn't show promising result, suggesting that it might be insufficient to understand the function of immune checkpoints in cancer merely in the context of immunity. Here, we found mutually exclusive expression patterns of the immune checkpoint VISTA (or VSIR) and the neural stemness factor SETDB1, an oncoprotein that promotes immunoevasion, in xenograft tumors, suggesting that cells with high VISTA expression represents a differentiated, and hence, less or non-malignant state in tumor. Non-neural differentiation factors HHEX, MYOD1 and PPARG promote, whereas oncoproteins KRAS (and the mutant KRAS(G12D)) and SOX2, both being embryonic neural factors, repress VISTA expression. This tendency can be inferred from the finding that neural stemness is the core property of cancer cell. Manipulated expression of VISTA in cancer cells generated no significant effect on cell tumorigenicity and differentiation state, but led to change in cell morphology and actin cytoskeleton. Mechanistically, VISTA regulates a key cytoskeleton regulator, WASF2, leading to the change in cell morphology, which might interfere with signal transduction of immune response. The results suggest that 1) high expression of a protein in tumor might represent a less or non-malignant state, targeting of which would leave malignant cells intact, and consequently, leading to weak or even no therapeutic efficacy, a key factor worth considering for target selection; 2) immune checkpoints might play other roles in cells that interfere with regulation of anti-tumor immunity.

Cancer is a serious public health problem, and is becoming more common, with a projected increase in deaths and more than 25 million new cases in coming decades. A number of molecular mechanisms are involved in the tumoral process, with one of them, never in mitosis A-related kinase 2 (NEK2), a serine/threonine protein kinase, being a frequent target of amplification in various malignancies that is responsible for chromosomal instability, aneuploidy and activation of several oncogenic pathways. Available kinase inhibitors are not yet optimized in terms of their pharmacokinetic properties for clinical use, and current therapies, such as chemotherapeutic agents or immunotherapies are often limited by their resistance. In silico methods represent an effective tool to search for novel potent inhibitors, before testing in animals, with time constraints and limited resources. To find new inhibitors of NEK2, we used E pharmacophore-based modeling and structure based virtual screening in this study. NEK2 was chosen as the target for therapeutic intervention and an energy optimized pharmacophore model was employed to screen the Enamine REAL library of millions of compounds. Pharmacodynamic and Pharmacokinetic properties of the Top hits were tested using ADMET profiling. These were further screened using molecular docking (standard precision and extra precision) and virtual screening to obtain three lead compounds 1, 2, and 3 which have docking score of -7.414, -8.037 and -7.562 respectively. MM-GBSA calculations were used to estimate the binding free energies for these complexes, which were determined to be -54.92, -54.18 and -49.23 kcal/mol. Lastly, 100 ns molecular dynamics simulations have been run to evaluate complex stability in dynamic situations. The overall results of the MD showed the overall stability of the NEK2-ligand complexes, and thus these three compounds are promising NEK2 inhibitor candidates and could be further validated in vitro and in vivo for clinical application. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=133 SRC="FIGDIR/small/742111v1_ufig1.gif" ALT="Figure 1"> View larger version (70K): org.highwire.dtl.DTLVardef@14e9cfeorg.highwire.dtl.DTLVardef@24ec78org.highwire.dtl.DTLVardef@20be75org.highwire.dtl.DTLVardef@1b80c02_HPS_FORMAT_FIGEXP M_FIG C_FIG

Despite significant advancements in microsurgical techniques in recent years, the treatment and prognosis of craniopharyngiomas remain unsatisfactory. As a central nervous system tumor located adjacent to important brain structures such as the hypothalamus-pituitary axis and accompanied by a highly inflammatory microenvironment, the tumor heterogeneity and tumor microenvironment characteristics of papillary craniopharyngiomas (PCPs) remain unclear. In this study, we integrated multimodal single-cell and spatial profiling from PCP tissue and peripheral blood mononuclear cells (PBMCs) to elucidate the tumor heterogeneity and microenvironment characteristics of PCP. Our single-cell and spatial analyses defined four specific tumor cell states in PCP, representing specific transcriptional regulatory programs and spatial heterogeneity characteristics during tumor progression. By constructing a spatial niche composed of tumor, immune, and stromal cells, we analyzed the cellular and spatial ecosystem of PCP at multiple levels to further assess the communication relationships between different tumor cell states and microenvironment cells. This study established a multidimensional molecular atlas of PCP from the perspectives of cell state, spatial structure, and microenvironment interactions, providing a foundation for understanding its biological behavior and exploring new intervention strategies.

Excessive alcohol intake is frequently associated with hypertriglyceridemia, a condition that increases the risk of severe complications including acute pancreatitis and cardiovascular disease. The very low-density lipoprotein (VLDL) receptor (VLDLR) promotes uptake of apoE-containing VLDL particles by peripheral tissues and plays an important role in maintaining plasma triglyceride (TG) homeostasis. Brown adipose tissue (BAT) is a major metabolic organ that contributes to circulating lipid clearance during thermogenic activation. It was reported that cold-induced thermogenesis upregulates VLDLR expression in BAT and reduces plasma TG via VLDL uptake. However, whether BAT VLDLR-mediated VLDL uptake regulates alcohol-induced hypertriglyceridemia remains unknown. Here, we generated BAT-specific fatty acid synthase (FASN) knockout mice (FASNBKO) and subjected them to binge and acute-on-chronic alcohol feeding paradigms. We found that BAT FASN deficiency enhanced thermogenic function and promoted VLDL uptake, resulting in attenuation of alcohol-induced elevations in plasma TG. Consistent with these findings, pharmacological inhibition of FASN by TVB3664 treatment in differentiated brown adipocytes (bADs) increased thermogenic gene expression and VLDL uptake under both control and alcohol-exposed conditions. In addition, FASNBKO mice were protected from alcohol-induced hepatic steatosis, which was accompanied by increased hepatic AMP-activated-protein kinase (AMPK) activation and enhanced {beta}-oxidation. Furthermore, FASNBKO mice exhibited upregulated FGF21 mRNA expression in the BAT and elevated circulating FGF21 levels. Similarly, TVB3664-treated differentiated bADs showed higher FGF21 expression and increased FGF21 content in culture medium. Taken together, these findings identify the important role of brown adipocyte FASN in regulating thermogenic function and TG homeostasis during alcohol exposure and suggest that enhancing thermogenic lipid utilization in BAT may represent a potential therapeutic strategy for mitigating alcohol-associated increases in plasma TG and hepatic fat accumulation.

Background: Bladder cancer has entered an era in which immune checkpoint blockade (ICB) and antibody-drug conjugate (ADC)-based combinations are reshaping clinical management. However, transcriptomic scores that connect prognosis, tumor microenvironment state, and treatment response are incompletely defined. Methods: Open-access TCGA-BLCA RNA-seq, clinical, mutation, copy-number, and RPPA data were downloaded from the Genomic Data Commons (GDC). Tumor-normal differential expressions, survival screening, LASSO-Cox modeling, train-test validation, GEO validation, pathway enrichment, immune signature scoring, mutation/CNV/RPPA support, drug sensitivity prediction, single-cell/spatial localization, and ICB validation were performed using reproducible Python and R scripts. A reduced model was derived using only genes shared by TCGA, GSE13507, and GSE31684. The fixed formula was then applied without refitting to IMvigor210 and GSE176307. Results: A five-gene model composed of EMP1, AHNAK, TNFRSF14, CLEC2D, and GSDMB retained TCGA internal prognostic value (train C-index 0.693, test C-index 0.605, all-sample C-index 0.667; TCGA test log-rank p = 0.015), although GEO survival validation in GSE13507 and GSE31684 was modest. High-risk tumors were enriched for epithelial-mesenchymal transition (EMT), TNF-alpha/NF-kB signaling, inflammatory response, hypoxia, complement, CAF, macrophage, checkpoint, and cytotoxic programs. Single-cell and spatial analyses localized the score to basal tumor, endothelial, fibroblast, and perivascular compartments. In IMvigor210, risk scores were higher in ICB non-responders than responders (Wilcoxon p = 0.044; AUC for non-response = 0.580), high-risk tumors had a lower responder rate (17.6% vs. 28.0%), and high risk predicted poorer OS (log-rank p = 0.016; multivariate continuous risk HR = 3.15, p = 0.044). GSE176307 showed directionally consistent but non-significant response results (AUC = 0.576). Conclusions: The five-gene score is best interpreted not as a standalone universal prognostic classifier, but as a compact stromal-EMT and immune-suppression phenotype associated with inferior ICB response. These findings support a framework linking prognosis, microenvironment biology, immunotherapy resistance, and therapeutic hypotheses in bladder cancer.

Background/Objectives: Cancer survivors frequently experience long-term neurocognitive impairments following chemotherapy and cranial irradiation, yet experimental models that enable mechanistic investigation of therapy-induced neurotoxicity at the transcriptional level remain limited. This study aimed to develop a human three-dimensional (3D) neural tissue model derived from L-Myc immortalized neural stem cells (LMNSCs) and use transcriptomic profiling to identify molecular pathways underlying chemotherapy- and radiation-induced neural injury and extracellular vesicle (EV)-mediated recovery. Methods: LMNSCs were differentiated in a 3D, methylcellulose-based culture to generate neural tissue containing neurons, astrocytes, and oligodendrocytes. Cultures were exposed to methotrexate (MTX) or ionizing radiation to induce neural injury and subsequently treated with LMNSC-derived EVs. Neural injury and repair mechanisms were evaluated by immunocytochemistry and bulk transcriptomics. Results: MTX and irradiation induced dose-dependent injury, exhibited by loss of neuronal complexity and reduced glial populations. LMNSC-EV treatment promoted recovery of neuronal and glial populations following MTX- and irradiation-induced injury. Transcriptomic analysis of irradiated cultures revealed activation of inflammation, DNA damage, and stress-response pathways, which were attenuated after treatment with LMNSC-EVs. Conclusions: LMNSC-based 3D neural tissue provides a human-relevant platform for modeling cancer therapy-induced neurotoxicity. Furthermore, LMNSC-EVs represent a promising cell-free regenerative therapeutic that restores injury-associated inflammatory, stress, and metabol-ic transcriptional programs after radiation-induced neural injury.

This study proposes a novel therapeutic strategy to suppress cancer growth by modulating the MDM2-p53 axis via Alternative Polyadenylation (APA). MDM2 normally promotes tumorigenesis by ubiquitinating and degrading the tumor suppressor p53. In cancer cells, preferential use of proximal polyadenylation signals (PAS) results in shortened 3'UTRs, allowing oncogenic transcripts like MDM2 to evade nuclear sequestration mediated by Inverted Alu (IRAlu) double-stranded RNA structures. We hypothesized that forcing distal PAS usage would elongate the MDM2 mRNA, promoting its nuclear retention and reducing protein translation, thereby restoring p53 activity. Using CRISPR-Cas9, we targeted and deleted the most frequent proximal PAS in the MDM2 3'UTR of A549 cells. Successful genome editing was confirmed via PCR. As expected, Western blot analysis showed a significant reduction in MDM2 expression in PAS-edited cells. However, experimental outcomes contradicted our initial hypothesis: edited cells exhibited higher viability under doxorubicin treatment compared to wild-type cells. Furthermore, despite decreased MDM2 levels, a concurrent reduction in phosphorylated p53 (p-p53) was observed. These unexpected results suggest that MDM2 3'UTR elongation may trigger a non-canonical regulatory mechanism that bypasses the traditional MDM2-p53 interaction. This study highlights the complexity of post-transcriptional regulation and suggests that APA-mediated gene modulation can induce unforeseen compensatory survival pathways in cancer cells, necessitating further investigation into the broader functional landscape of elongated 3'UTRs.

Mitochondrial plasticity, characterized by the dynamic balance between glycolysis and oxidative phos-phorylation in response to genetic and microenvironmental changes, is a hallmark of melanoma progression. Sphingolipids play a significant role in various aspects of cancer cell biology, including metabolic reprogramming. Previous observations had shown that the lysosomal sphingolipid-metabolizing enzyme {beta}-galactosylceramidase (GALC) rewires the lipid profile of mouse melanoma cells, exerting pro-oncogenic functions, gene silencing leading to a decreased oncogenic activity in murine and human melanoma cells. Here, we have focused on the mitochondrial sphingolipid composition and energetic metabolism in GALC knockout (KO) A2058 human melanoma cells. Targeted analysis of the mitochondrial sphingolipid profile, transcriptomic data, and mitochondrial structural and functional studies indicate that GALC loss drives a sphingolipid-mediated reprogramming of mitochondrial metabolism in absence of major structural alterations, characterized by bioenergetic insufficiency possibly due to ceramide- and sphingomyelin-driven impairment of respiratory chain function. Overall, these data indicate that GALC KO leads to a sphin-golipid-driven mitochondrial metabolic suppression and may provide novel information for the development of efficacious approaches in mitochondrial targeting melanoma therapies.

Retrotransposons are repetitive DNA elements normally suppressed through epigenetic mechanisms. In aging and neurodegenerative diseases, abnormal retrotransposon activation occurs and leads to neurotoxicity. However, whether ischemic stroke induces retrotransposon activation remains unclear. Here, we investigated whether cerebral ischemia triggers dysregulation of retrotransposon in the brain. Since brain ischemia leads to tissue acidosis, we further examined whether acidosis contributes to this response. We performed 45 min of transient middle cerebral artery occlusion (tMCAO) followed by reperfusion on adult wild-type mice, then measured expression of retrotransposons LINE-1, IAP, ETn2 and SINE B2 in ipsilateral brain tissue using RT-qPCR. Retroviral GAG protein expression was examined by Western blotting. In vitro, we exposed neuro-2a (N2A) cells to acidic extracellular pH (6.4 or 6.0) and retrotransposon transcripts were analyzed. We found that ischemia-reperfusion increased expression of IAPEz-gag and ETn2 in ipsilateral ischemic brain tissue at 24 h, with stronger induction of LINE-1 Orf1, IAPEz-gag and B2 in infarct than peri-infarct brain regions. Western blotting analysis revealed dynamic changes in GAG proteins, with no detectable changes at 6 h of reperfusion followed by reduced levels of the precursor Pr65 and mature capsid p30 products at 24 h. In N2A cells, extracellular acidosis induced time-dependent increases in LINE-1 Orf1, IAPEz-gag and B2 transcripts. These findings identify retrotransposon dysregulation as a molecular feature of ischemic brain injury and provide a framework for further investigating its role in stroke pathology.

TUBB4A-related leukodystrophy (TUBB4A-LD) is a rare neurologic disorder with a broad spectrum of phenotypes, including severe early infantile encephalopathy, late infantile Hypomyelination with Atrophy of the Basal ganglia and Cerebellum (H-ABC), and milder late infantile forms. H-ABC is closely associated with a recurrent pathogenic variant, p.Asp249Asn, in the gene encoding tubulin beta class IVA (TUBB4A), a microtubule component. H-ABC presents with progressive dystonia, mobility loss, aphasia, and swallowing dysfunction in childhood. H-ABC results in cell-autonomous deficits in oligodendrocytes (OLs), cerebellar granule neurons, and medium spiny neurons (MSNs). Antisense oligonucleotides targeting Tubb4a can alleviate symptoms in H-ABC mouse models. However, the efficacy and safety of TUBB4A knockout in human cells remain poorly understood. We studied patient-derived TUBB4AD249N, TUBB4A KO, and control individual pluripotent stem cells (iPSCs). TUBB4AD249N iPSC-derived OLs failed to mature, showing less complexity and myelination, reduced microtubule acetylation and detyrosination. TUBB4AD249N iPSC-derived MSNs also showed impaired maturation and neurite extension. TUBB4A KO in mutant iPSCs reduced cellular deficits and was well tolerated. These findings support that suppression of TUBB4A could be a safe, effective therapy for TUBB4A-LD.

Key elements of eukaryotic antiviral immunity are evolutionarily conserved with prokaryotic anti-phage defense systems. The Overcoming Lysogenization Defect (OLD) anti-phage defense system is well characterized in prokaryotes but has remained unknown in eukaryotes. Here, the old-like genes are identified in certain aquatic eukaryotes, including the SAR supergroup, Filasterea, Chytridiomycota, and some metazoan lineages (Placozoa, Cnidaria, Spiralia, Hemichordata, and Cephalochordata). Within molluscs, old-like genes are present in bivalves but absent in gastropods and cephalopods. Interestingly, the filasterean Capsaspora owczarzaki, an endosymbiont of the gastropod Biomphalaria glabrata, encodes putative secreted OLD-like proteins, suggesting it may provide its host with symbiont-mediated antiviral protection. Genomic and transcriptomic analyses revealed that old-like genes vary in copy and intron number and are expressed in some eukaryotic lineages. OLD-like proteins retain key structural features but exhibit a different topology from that of prokaryotes. Structural predictions reveal homodimeric dsDNA-bound architectures analogous to that of the Bacillus cereus VD045 GajA OLD homodimer. Furthermore, phylogenetic analysis divided OLD-like proteins into three distinct clusters, one of which likely represents an ancient inheritance from the ancestral Promethearchaeota (formerly Asgard archaea) host. Together, these findings highlight an unexpected presence of old-like genes in certain aquatic eukaryotes, offering new insights into their evolutionary history and potential role in antiviral defense.

Background: Gastric carcinoma remains a major cause of cancer related mortality worldwide, with tumor progression increasingly recognized as a consequence of complex interactions within the tumor microenvironment. Hypoxia induced signaling, cancer associated fibroblast (CAF) heterogeneity, and immune checkpoint activation play critical roles in tumor progression and immune evasion. However, their integrated relationship in gastric carcinoma remains insufficiently characterized. Objectives: To evaluate the expression of Hypoxia inducible factor 1 alpha and its association with cancer-associated fibroblast subtypes and Programmed death-ligand 1 expression in gastric carcinoma. Methods: This cross sectional analytical study included 100 histologically confirmed gastric carcinoma cases from Satkhira Medical College. Immunohistochemistry was performed for HIF 1 alpha, smooth muscle actin (SMA), fibroblast activation protein (FAP), and PD L1. CAFs were subclassified into myofibroblastic CAFs (myCAFs) and inflammatory CAFs (iCAFs). Associations between biomarkers and clinicopathological variables were analyzed using chi square test, Spearman correlation, and multivariate logistic regression. Receiver operating characteristic (ROC) curve analysis was used to assess model performance. Result: High HIF 1 alpha expression was observed in 55% of cases and demonstrated significant association with poor differentiation (p = 0.001), advanced tumor stage (p = 0.002), and lymph node metastasis (p = 0.001). iCAF predominance was significantly associated with poor differentiation (p = 0.003), advanced stage (p = 0.004), and nodal metastasis (p = 0.004). High PD L1 expression was significantly associated with poor differentiation (p = 0.03), advanced stage (p = 0.001), and lymph node metastasis (p = 0.002). Multivariate logistic regression identified high HIF 1 alpha expression (OR = 3.8, p = 0.001), iCAF dominance (OR = 4.5, p < 0.001), and advanced tumor stage (OR = 2.9, p = 0.004) as independent predictors of high PD L1 expression. Combined high HIF 1 alpha expression and CAF activation demonstrated the highest rate of PD L1 positivity (76.7%, p < 0.001). ROC curve analysis demonstrated good predictive performance of the model with an area under the curve of 0.81. Conclusion: The present study demonstrates a significant interaction between hypoxia, stromal remodeling, and immune checkpoint activation in gastric carcinoma. High HIF 1 alpha expression and inflammatory CAF predominance are strongly associated with aggressive clinicopathological features and increased PD L1 expression, supporting the existence of a coordinated hypoxia stroma immune axis in gastric carcinoma progression. These findings may have potential implications for prognostic stratification and combined targeted therapeutic strategies.

In TMPRSS2 fusion-positive prostate cancer, ERR is involved in regulation of ERG and promotes the androgen receptor independent signaling in the cancer progression. The ERR binds to the ERREs (estrogen-related receptor response elements) present at -5042 bp of the TMPRSS2- promoter and enhances the ERG overexpression that causes prostate cancer progression. To dissect the structural basis of the ERR recognition to the TMPRSS2 promoter DNA, we have purified the full-length ERR (ERRFL), NTD deleted construct (ERR{Delta}NTD), and the DNA-binding domain (ERRDBD) proteins and performed the binding analysis with 30 bp TMPRSS2-promoter DNA (5' -AGTCCAAGGTCGGTGGATC ACAAGGTCAGG-3'). Circular dichroism analysis showed that all three ERR proteins adopt native secondary structures. DNA binding induced subtle changes in the secondary structures, while enhancing the thermal stability (Tm) of all ERRa proteins. Binding analysis showed that ERRDBD bound weakly to the DNA, whereas ERRFL and ERR{Delta}NTD exhibited substantially higher affinities ~120-fold and ~131-fold than ERRaDBD, respectively. Small-angle X-ray scattering (SAXS) analyses revealed a dimeric ERRFL structure and an ERRFL-DNA complex (2:1) structure in solution and fitted well with Alpha Fold model of apo and DNA bound complex of ERRFL. Furthermore, 100 ns dynamics simulations on apo and DNA-bound ERRa proteins showed that all proteins remained structurally stable, with flexibility largely confined to loop regions of ERRa proteins. Our biophysical, DNA binding and structural analyses have revealed the mechanism involved in ERR recognition of the TMPRSS2- promoter DNA, which provides insight into ERR-mediated transcriptional regulation and development of anticancer drugs against ERR-driven prostate cancer.

The long non-coding RNA Negative Regulator of Antiviral Response (NRAV) is known to suppress antiviral immunity by regulating interferon response, but its functional role in tumor immunology remains poorly understood. We examined the relevance of NRAV in melanoma and found that high NRAV expression was associated with poor survival, reduced inflammatory pathway activation, and resistance to immune checkpoint blockade. Bulk and single-cell transcriptomic profiling indicates that NRAV expression is selectively enriched in malignant cells suggesting a potential cancer cell-intrinsic function. To examine whether NRAV can regulate inflammatory responses in melanoma cells, we manipulated the levels of NRAV in the BRAF-mutant A375 melanoma model and characterized the expression of key interferon-stimulated genes (ISGs) following type-I and type-II interferon stimulation. Our findings reveal that the stable NRAV overexpression blunts the induction of key ISGs, whereas NRAV knockdown reciprocally amplifies their transcription. Subcellular fractionation revealed that NRAV is predominantly localized to the nuclear compartment of melanoma cells and the overexpression of NRAV altered regulatory histone marks on the target ISG promoters including MX1 and IFITM3. Collectively, these findings establish NRAV as a tumor-intrinsic epigenetic regulator of interferon signaling, highlighting its potential contribution to melanoma immune evasion.

Lung cancer continues to be the leading cause of cancer-related mortality globally, with non-small cell lung cancer (NSCLC) representing the most prevalent subtype. Tumor hypoxia is a characteristic feature of the neoplastic microenvironment in NSCLC, facilitating tumor progression and conferring resistance to oxidative stress through the stabilization of hypoxia-inducible factor-1 alpha (HIF-1). In this study, we investigated the combined anticancer effects of baicalein (Bai), a natural flavonoid, and thermal-cycling stimulation (TCS), a physical treatment that minimizes damage to normal cells, under cobalt (II) chloride (CoCl2)-induced hypoxic conditions in NSCLC. In A549 NSCLC cells, the combination of Bai and TCS significantly decreased cell viability and induced apoptosis, while exhibiting minimal cytotoxicity on IMR-90 normal human lung fibroblast cells. On a mechanistic level, this combined treatment suppressed the expression of HIF-1 and superoxide dismutase 2 (SOD2) proteins, elevated intracellular reactive oxygen species (ROS) levels, and impaired DNA repair capability by downregulating MutT homolog 1 (MTH1) protein expression. Additionally, disruption of mitochondrial membrane potential and increased poly (ADP-ribose) polymerase (PARP) cleavage further confirmed the induction of apoptosis. These findings indicate that combining Bai with TCS offers a promising synergistic approach to treating NSCLC under hypoxic conditions.

PARK7 (DJ-1) is a redox-sensitive stress-response protein that supports cellular adaptation, but its role in post-transcriptional responses to genotoxic stress remains unclear. We investigated whether DJ-1 abundance determines the miRNA response to X-ray-induced DNA damage. Integrated mRNA-seq and small RNA-seq across DJ-1 states in HEK293 cells revealed a striking divergence in miRNA plasticity. DJ-1 depletion by siRNA produced minimal miRNA remodeling, with only 34 (6.3%) miRNAs differentially expressed after irradiation. In contrast, elevated DJ-1 markedly increased miRNA plasticity: irradiation altered [~]37% of detectable miRNAs, accounting for [~]90% of miRNA reads, and extensively redistributed the miRNA pool. DJ-1 overexpression was also associated with remodeling of the miRNA regulatory machinery, particularly components involved in miRNA sorting and stability, suggesting feedback regulation of the miRNA pool. Comparison of precursor and mature species revealed substantial uncoupling between transcription and mature miRNA abundance, implicating regulation at the levels of processing, maturation, or stability. Radiation-responsive coding genes in DJ-1-overexpressing cells were relatively depleted of miRNA binding sites, supporting preferential regulation of upstream regulatory nodes rather than the bulk transcriptome. Together, these findings identify DJ-1 as a determinant of post-transcriptional signaling plasticity, enabling dynamic remodeling of the miRNA regulatory state in response to genotoxic stress. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=133 SRC="FIGDIR/small/744036v1_ufig1.gif" ALT="Figure 1000"> View larger version (38K): org.highwire.dtl.DTLVardef@18824aorg.highwire.dtl.DTLVardef@111d8bcorg.highwire.dtl.DTLVardef@ac33b4org.highwire.dtl.DTLVardef@17698d3_HPS_FORMAT_FIGEXP M_FIG C_FIG