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UBE2D4 Upregulation Promotes Cuproptosis Sensitivity in Colorectal Cancer.

BACKGROUND: Cuproptosis, a copper-dependent form of regulated cell death, represents a potential therapeutic vulnerability in colorectal cancer (CRC). However, the regulatory mechanisms governing cuproptosis in CRC remain largely unknown. METHODS: UBE2D4 expression was analyzed in the TCGA-COAD cohort and validated in CRC cell lines (HCT116, HT29) and normal colon epithelial cells (FHC) by qRT-PCR and western blot. Paired CRC and adjacent normal tissues (n = 5) were also examined by western blot. UBE2D4-knockdown HT29 cells were generated by transient siRNA transfection to assess cell viability (CCK-8), migration (wound healing assay), and expression of cuproptosis-related genes (DLAT, HSP70, LIAS) under copper overload conditions (elesclomol+CuSO4). RESULTS: UBE2D4 was significantly upregulated in CRC tissues and cell lines compared to normal controls. In paired clinical samples, western blot confirmed that UBE2D4 protein expression was elevated in tumor tissues, accompanied by increased DLAT, HSP70 and LIAS. Copper overload induced typical cuproptotic mitochondrial morphology and triggered a marked upregulation of UBE2D4, DLAT, and HSP70, alongside downregulation of LIAS. UBE2D4 silencing had no effect on baseline cell viability or migration but significantly rescued cells from copper-induced cytotoxicity. Genetically, UBE2D4 knockdown specifically attenuated the copper-induced elevation of DLAT, while restoring HSP70 and LIAS to near-baseline levels. CONCLUSION: These findings identify UBE2D4 as a genetically upregulated and functionally significant gene in colorectal cancer. Its upregulation correlates with altered expression of cuproptosis-related genes, particularly DLAT, suggesting that UBE2D4 expression status may represent a genetic determinant of cuproptosis sensitivity in CRC. This study provides a genetic basis for stratifying CRC patients who might benefit from copper-based therapeutic strategies.

Humans

Translational diffusion of class II major histocompatibility complex molecules is constrained by their cytoplasmic domains.

Site-directed mutagenesis in vitro was used to introduce stop codons in the genomic DNA of the alpha and beta chains of the murine class II major histocompatibility complex antigen, I-Ak. Mutated DNA was transfected into B lymphoma cells that were then selected by neomycin resistance and for their ability to express I-Ak molecules on their plasma membrane. The translational diffusion coefficient (Dlat) of I-Ak molecules composed of a wild-type beta chain paired with an alpha chain missing either 6 or 12 amino acids from the cytoplasmic domain is on the average threefold higher than the Dlat of wild-type I-Ak molecules as measured by fluorescence photobleaching and recovery. The removal of 12 amino acids from the cytoplasmic domain of the beta chain did not change the Dlat value from that of wild-type I-Ak if the truncated beta chain was paired with a wild-type alpha chain. Removing all amino acids of the cytoplasmic domains of both the alpha and beta chains resulted in a 10-fold increase in the Dlat, the highest value for any of the truncated I-Ak molecules tested. These data indicate that the carboxy-terminal six amino acids of the cytoplasmic domain of the alpha chain and the six plasma membrane-proximal amino acids of the beta chain are important in constraining the translational diffusion of I-Ak molecules in the plasma membrane.

Amino Acid Sequence

A TIGIT nanotrapping-guided STING-activatable immunometabolic strategy overcomes innate immune silence and T cell exhaustion in breast cancer.

Breast cancer exhibits a profoundly immunosuppressive tumor microenvironment (TME), where innate immune silence prevents antigen sensing and persistent T cell exhaustion limits effector responses, rendering most immunotherapies ineffective. Clinical profiling of 1093 The Cancer Genome Atlas (TCGA) cases identified a glucose-fueled glutathione (GSH)-glutathione peroxidase 4 (GPX4)-dihydrolipoamide S-acetyltransferase (DLAT) axis as a dominant metabolic shield that suppresses oxidative stress, and thereby enforces both stimulator of interferon genes (STING) silence and CD8+ T cell exclusion. To dismantle this barrier, we developed an immunometabolic nanotherapy, GOx/ES-CO-LDH@TIGIT-Nanotrap (TNT). In acidic tumors, proton-driven layered double hydroxide (LDH) disassembly releases glucose oxidase (GOx) and extremely small cuprous oxide (ES-CO). GOx depletes glucose and nicotinamide adenine dinucleotide phosphate (NADPH) to induce disulfidptosis, while ES-CO releases cuprous ions (Cu+) that trigger cuproptosis via binding to lipoylated mitochondrial proteins. Their mutual biochemical amplification produces a cycloacclerated disulfidptosis-cuproptosis cascade that collapses the GSH-GPX4-DLAT axis and restores STING activation. Meanwhile, the macrophage-derived T cell immunoreceptor with Ig and ITIM domains (TIGIT) Nanotrap sequesters CD155 to prevent T cell suppression. Together, this coordinated innate reactivation and adaptive rescue converts immune-cold tumors into STING-inflamed and T cell responsive lesions.

Female

Self-association of class I major histocompatibility complex molecules in liposome and cell surface membranes.

Fluorescent derivatives of a human MHC class I glycoprotein, HLA-A2, were reconstituted into dimyristoylphosphatidylcholine (DMPC) liposomes. Measurements of lateral diffusion of fluorescein-(Fl-) labeled HLA-A2 by fluorescence photobleaching recovery (FPR), of rotational diffusion of erythrosin-(Er-) labeled HLA-A2 by time-resolved phosphorescence anisotropy (TPA), and of molecular proximity by flow cytometric fluorescence resonance energy transfer (FCET) showed that these class I MHC molecules self-associate in liposome membranes, forming small aggregates even at low surface concentrations. The lateral diffusion coefficient (Dlat) of Fl-HLA-A2 decreases with increasing surface protein concentration over a range of lipid:protein molar ratios (L/P) between 8000:1 and 2000:1. The reduction in Dlat of HLA molecules in DMPC liposomes is found to be sensitive to time and temperature. The rotational correlation time for Er-HLA-A2 in DMPC liposomes at 30 degrees C is 87 +/- 0.8 microseconds, at least 10 times larger than that expected for an HLA monomer. There is also significant quenching of donor (Fl-HLA) fluorescence at 37 degrees C in the presence of acceptor-labeled (sulforhodamine-labeled HLA) protein indicating proximity between HLA molecules even at L/P = 4000:1. FPR and FCET measurements with another membrane glycoprotein, glycophorin, give no evidence for its self-association. HLA aggregation measured by FPR, FCET, and TPA was blocked by beta 2-microglobulin, b2m, added to the liposomes. The aggregation of HLA-A2 molecules is not an artifact of their reconstitution into liposomes. HLA aggregates, defined by FCET, were readily detected on the surface of human lymphoblastoid (JY) cells.(ABSTRACT TRUNCATED AT 250 WORDS)

B-Lymphocytes

Upper airway dimensions and movements in bronchial asthma.

We measured the diameter and vertical displacement of the laryngeal and oropharyngeal airways in 8 seated asymptomatic asthmatic subjects (31 to 60 yr of age) before and after bronchoconstriction (BC) induced by histamine phosphate aerosol. An image of the airways was obtained in 2 planes using an X-ray fluoroscope attached to a videotape recorder, onto which signals of flow and volume at the mouth were recorded simultaneously. We calculated real dimensions from the video image using size markers included in the picture. During BC, when FEV1 fell to 35 +/- 4% (mean +/- SE) of control, the lateral diameter (DLAT) of the larynx at mid-expiration narrowed over approximately 10 mm vertical height above the glottis. Lateral diameter of the glottis during mid-expiration fell from 6.5 +/- 1.5 mm by 46 +/- 12% (p less than 0.05), but that during inspiration was unchanged. In the 3 subjects with the greatest glottic narrowing, anteroposterior diameter (DAP) and DLAT of the larynx at the level of the corniculate cartilages narrowed by 28 and 27%, respectively. There was inspiratory dilatation of the oropharynx during BC. The DAP during inspiration at the level of the hyoid increased from 15.0 +/- 1.5 to 17.5 +/- 1.5 mm (p less than 0.05), while that at the level of the third cervical vertebra (C3) increased from 12.5 +/- 1.5 to 17.0 +/- 2.0 mm (p less than 0.05). The diameters during mid-expiration were unchanged so that the difference between inspiration and mid-expiration increased at both levels. Higher in the oropharynx (20 mm above C3), expiratory DAP decreased in 6 of 8 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Characteristics and modulation of dithranol (anthralin)-induced skin irritation in the mouse ear model.

Dithranol-induced skin irritation and the modulatory effects of different pharmacological agents were studied using the mouse ear model. A single topical application of dithranol caused a dose-dependent skin irritation which resulted in delayed swelling of the mouse ear with two separate peak responses, 1-2 and 6-10 days after application. The irritation was most effectively and persistently inhibited by topical treatment with corticosteroids, the free radical scavenger DL-alpha-tocopherol (DLAT) and the serotonin antagonist metergoline. The effect of corticosteroids, however, was slightly diminished during the second peak irritation. The lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA), the dual lipoxygenase and cyclo-oxygenase inhibitor tolfenamic acid and the cyclo-oxygenase inhibitor indomethacin as well as trifluoperazine retained their inhibitory activity. Of these compounds, indomethacin was active only during the first irritation peak, NDGA during both peaks and trifluoperazine principally during the second peak. Retinoic acid did not inhibit the ear swelling. The results confirm and extend the observations that the formation of free radicals is essential for dithranol inflammation. The inflammation can also be suppressed by inhibiting the formation of arachidonic acid or its pro-inflammatory metabolites.

Administration, Topical

Analysis of end-stage renal disease mediated by cuproptosis-related genes.

OBJECTIVE: The complex pathophysiological mechanism of end-stage renal disease (ESRD) has not been fully understood. Cuproptosis is a newly discovered type of programmed cell death. Therefore, this study attempts to clarify the relationship between cuproptosis-related genes (CRGs) and the phenotype of ESRD. MATERIALS AND METHODS: The National Center for Biological Information Gene Expression Omnibus database was applied to obtain the GSE37171 dataset comprising whole-genome microarray analysis of peripheral blood samples. A 3 : 1 case-control design was employed with 75 ESRD patients and 20 healthy controls who were frequency-matched for age, sex, and ethnicity. Based on differentially expressed genes (DEGs) and genes related to cuproptosis, CRGs were identified. Thereafter, we explored two different subpopulations based on the cuproptosis gene and analyzed their expression and immune infiltration. Genes specific to the CRG cluster were identified through the weighted gene co-expression network analysis algorithm, and the best prediction model was determined and verified by four machine learning methods. RESULTS: The study identified 14 differentially expressed CRGs, among which ATP7B, SLC31A1, LIAS, LIPT1, DLD, MTF1, CDKN2A, DBT, and DLST had relatively high expression levels in the ESRD samples. Compared with the control group, expression levels of FDX1, DLAT, PDHA1, PDHB, and GLS were significantly lower in the ESRD group, and CRGs played a key role in the regulation of immune infiltration in ESRD. Two cuproptosis-related molecular clusters were identified in the ESRD samples. Cluster2 was more correlated with the immune infiltration of ESRD. By analyzing the intersection points between CRG cluster and key genes of ESRD, a total of 888 specific DEGs were identified. Functional differences related to specific DEGs were further explored using gene set variation analysis. Five significant genes (SMC5, USP47, USP53, AGA, and DMXL1) were identified by the support vector machine model as key predictors for ESRD disease risk, achieving an area under the curve (AUC) of 1.00 in internal validation. However, external validation in independent cohorts is required prior to clinical application. Individual gene analysis showed an AUC > 0.81 in discriminating ESRD patients from healthy controls, and the expression of all 5 genes in ESRD patients was significantly lower than in the control group. CONCLUSION: This study clarified the relationship between CRGs and the phenotype of ESRD, analyzed their specific roles in the immune microenvironment, and obtained a predictive model, providing new insights for the study of its potential therapeutic targets.

Humans