Frontiers in bioscience (Landmark edition)最新文献

Bacterial Artificial chromosome (BAC) recombineering is a powerful genetic manipulation tool for the efficient development of recombinant genetic resources. Long homology arms of more than 150 kb composed of BAC constructs not only substantially enhance genetic recombination events, but also provide a variety of single nucleotide polymorphisms (SNPs) that are useful markers for accurately docking BAC constructs at target sites. Even if the BAC construct is homologous to the sequences of the target region, different variations may be distributed between various SNPs within the region and those within the BAC construct. Once the BAC construct carrying these variations was precisely replaced in the target region, the SNP profiles within the target genomic locus were directly replaced with those in the BAC. This alteration in SNP profiles ensured that the BAC construct accurately targeted the designated site. In this study, we introduced restriction fragment length polymorphism or single-strand conformation polymorphism analyses to validate and evaluate BAC recombination based on changes in SNP patterns. These methods provide a simple and economical solution to validation steps that can be cumbersome with large homologous sequences, facilitating access to the production of therapeutic resources or disease models based on BAC-mediated homologous recombination.

Objective: To explore the role and molecular mechanism of cancer-associated fibroblasts (CAFs) in the tumor microenvironment of gastric cancer (GC).

Methods: The expression of CAFs in GC patients was first assessed for abundance, and survival analysis was performed. Subsequently, The Cancer Genome Atlas (TCGA) data were used for differential analysis, survival analysis, and EPIC analysis, while single-cell data (GSE183904) were downloaded for differential analysis of CAFs. Clinical data pooling, univariate and multivariate Cox analysis, and immunofluorescence were carried out on clinical GC tissue samples to explore RCN3 expression within patient CAFs. Western blot and quantitative polymerase chain reaction (qPCR) were used to detect the expression of RCN3. The relationship between RCN3, PCSK6, and STAT1 was explored by chromatin immunoprecipitation (CHIP) experiments, and the effects of the genes on macrophage polarization were detected by detecting biomarkers of biological M1/M2.

Results: CAFs in GC were found to be significantly higher compared to the normal group. Revealing the results of TCGA differential analysis, it was observed that GC exhibited a substantial upregulation in the expression levels of RCN3. The clinical statistics indicate a positive correlation between an elevated level of RCN3 expression and the T-stage classification of tumor size. In addition, RCN3 was found to have a significant impact on the overall survival of patients with gastric cancer, acting as an independent prognostic indicator. Analysis of single-cell data showed high expression of PCSK6 in macrophages, and immunofluorescence staining of samples from GC patients showed increased expression of PCSK6 on the cell membranes of macrophages in GC tissues. The subsequent cellular experiments confirmed RCN3 protein can regulate the expression of PCSK6, and PCSK6 regulates macrophage polarization through STAT1.

Conclusions: CAFs regulate macrophage polarization through the RCN3/PCSK6/STAT1 pathway in GC.

Colitis-associated cancer (CAC) is the most serious complication of inflammatory bowel disease. In recent years, the incidence of CAC has increased worldwide. Oxidative stress (OS) is involved in the development of CAC through oxidative damage to biomolecules or activation of inflammatory signaling pathways. Exosomes are extracellular vesicles that act as messengers to deliver signals and macromolecules to target cells, making them important mediators of intercellular communication and exchange of biologically active molecules between cells. MicroRNAs (miRNAs) carried by exosomes regulate the pro- and anti-inflammatory pathways of OS and play a key role in communication between OS and cancer cells. This review describes the correlation between OS and exosomal miRNAs with the goal of identifying a novel therapeutic method for CAC.

Background: Many plant secondary metabolites (PSMs) were shown to intercalate into DNA helix or interact with DNA grooves. This may influence histone-DNA interactions changeing chromatin structure and genome functioning.

Methods: Nucleosome stability and linker histone H1.2, H1.4 and H1.5 localizations were studied in HeLa cells after the treatment with 15 PSMs, which are DNA-binders and possess anticancer activity according to published data. Chromatin remodeler CBL0137 was used as a control. Effects of PSMs were studied using fluorescent microscopy, flowcytometry, quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR), western-blotting.

Results: We showed that 1-hour treatment with CBL0137 strongly inhibited DNA synthesis and caused intensive linker histone depletion consistent with nucleosome destabilization. None of PSMs caused nucleosome destabilization, while most of them demonstrated significant influence on linker histone localizations. In particular, cell treatment with 11 PSMs at non-toxic concentrations induced significant translocation of the histone H1.5 to nucleoli and most of PSMs caused depletion of the histones H1.2 and H1.4 from chromatin fraction. Curcumin, resveratrol, berberine, naringenin, and quercetin caused significant redistribution of all three variants of the studied linker histones showing some overlap of PSM effects on linker histone DNA-binding. We demonstrated that PSMs, which induced the most significant redistribution of the histone H1.5 (berberine, curcumin and naringenin), influence the proportion of cells synthesizing DNA, expressing or non-expressing cyclin B and influence cell cycle distribution. Berberine induction of H1.5 translocations to nucleoli was shown to occur independently on the phases of cell cycle (metaphase was not analyzed).

Conclusions: For the first time we revealed PSM influence on linker histone location in cell nuclei that opens a new direction of PSM research as anticancer agents.

Background: The switching/sucrose non-fermentable (SWI/SNF) Related, Matrix Associated, Actin Dependent Regulator Of Chromatin, Subfamily A (SMARCA) member 2 and member 4 (SMARCA2/4) are paralogs and act as the key enzymatic subunits in the SWI/SNF complex for chromatin remodeling. However, the role of SMARCA2/4 in DNA damage response remains unclear.

Methods: Laser microirradiation assays were performed to examine the key domains of SMARCA2/4 for the relocation of the SWI/SNF complex to DNA lesions. To examine the key factors that mediate the recruitment of SMARCA2/4, the relocation of SMARCA2/4 to DNA lesions was examined in HeLa cells treated with inhibitors of Ataxia-telangiectasia-mutated (ATM), Ataxia telangiectasia and Rad3-related protein (ATR), CREB-binding protein (CBP) and its homologue p300 (p300/CBP), or Poly (ADP-ribose) polymerase (PARP) 1/2 as well as in H2AX-deficient HeLa cells. Moreover, by concomitantly suppressing SMARCA2/4 with the small molecule inhibitor FHD286 or Compound 14, the function of SMARCA2/4 in Radiation sensitive 51 (RAD51) foci formation and homologous recombination repair was examined. Finally, using a colony formation assay, the synergistic effect of PARP inhibitors and SMARCA2/4 inhibitors on the suppression of tumor cell growth was examined.

Results: We show that SMARCA2/4 relocate to DNA lesions in response to DNA damage, which requires their ATPase activities. Moreover, these ATPase activities are also required for the relocation of other subunits in the SWI/SNF complex to DNA lesions. Interestingly, the relocation of SMARCA2/4 is independent of γH2AX, ATM, ATR, p300/CBP, or PARP1/2, indicating that it may directly recognize DNA lesions as a DNA damage sensor. Lacking SMARCA2/4 prolongs the retention of γH2AX, Ring Finger Protein 8 (RNF8) and Breast cancer susceptibility gene 1 (BRCA1) at DNA lesions and impairs RAD51-dependent homologous recombination repair. Furthermore, the treatment of an SMARCA2/4 inhibitor sensitizes tumor cells to PARP inhibitor treatment.

Conclusions: This study reveals SMARCA2/4 as a DNA damage repair factor for double-strand break repair.

Background: The ability to maintain muscle function decreases with age and loss of proteostatic function. Diet, drugs, and genetic interventions that restrict nutrients or nutrient signaling help preserve long-term muscle function and slow age-related decline. Previously, it was shown that attenuating protein synthesis downstream of the mechanistic target of rapamycin (mTOR) gradually increases expression of heat shock response (HSR) genes in a manner that correlates with increased resilience to protein unfolding stress. Here, we investigate the role of specific tissues in mediating the cytoprotective effects of low translation.

Methods: This study uses genetic tools (transgenic Caenorhabditis elegans (C. elegans), RNA interference and gene expression analysis) as well as physiological assays (survival and paralysis assays) in order to better understand how specific tissues contribute to adaptive changes involving cellular cross-talk that enhance proteostasis under low translation conditions.

Results: We use the C. elegans system to show that lowering translation in neurons or the germline increases heat shock gene expression and survival under conditions of heat stress. In addition, we find that low translation in these tissues protects motility in a body muscle-specific model of proteotoxicity that results in paralysis. Low translation in neurons or germline also results in increased expression of certain muscle regulatory and structural genes, reversing reduced expression normally observed with aging in C. elegans. Enhanced resilience to protein unfolding stress requires neuronal expression of cbp-1.

Conclusions: Low translation in either neurons or the germline orchestrate protective adaptation in other tissues, including body muscle.

Background: The involvement of gut microbiota in carcinogenesis has gradually been highlighted in past decades. Bacteria could play its role by the secretion of extracellular vesicles (EVs); however, interrelationship between bacterial EVs and hepatocellular carcinoma (HCC) development has not been investigated much.

Methods: Diethylnitrosamine (DEN) was utilized to produce HCC model in mice, of which fecal was collected for detecting Bifidobacterium longum (B.longum) with real-time polymerase chain reaction (PCR). EV isolated from B.longum (B.longum-EV) with ultracentrifugation were stained with PKH26 to investigate the cellular uptake of murine hepatocytes (AML12). After treatment with B.longum-EV, TGF-β1-induced AML12 cells were subjected to morphological observation, fibrosis- and apoptosis-related marker detection with western blot, apoptotic ratio and reactive oxygen species (ROS) level analysis with flow cytometry, and oxidative stress biomarker assessment with enzyme-linked immunosorbent assay (ELISA); meanwhile, animal studies including liver function, tumor formation rate, and histological analysis, were also performed to investigate the role of B.longum-EV in the fibrosis, apoptosis, oxidative stress, and carcinogenesis of the liver in vivo.

Results: The levels of B.longum were significantly reduced in HCC model mice. B.longum-EV could enter AML12 cells and effectively attenuate TGF-β1-induced fibrosis, apoptosis, and oxidative stress in AML12 cells. In vivo studies showed that B.longum-EV administration alleviated DEN-induced liver fibrosis, apoptosis, and oxidative stress at the early stage. Moreover, B.longum-EV administration also effectively reduced the tumor formation rate and liver function injury in DEN-induced mice and down-regulated TGF-β1 expression and Smad3 phosphorylation of mouse liver.

Conclusions: B.longum-EVs protect hepatocytes against fibrosis, apoptosis, and oxidative damage, which exert a potential of preventing HCC development.

Background: Uncontrolled cellular proliferation may result in the progression of diseases such as cancer that promote organism death. Programmed cell death (PCD) is an important mechanism that ensures the quality and quantity of cells, which could be developed as a potential biomarker for disease diagnosis and treatment.

Methods: RNA-seq data and clinical information of nasopharyngeal carcinoma (NPC) patients were downloaded from the Gene Expression Omnibus (GEO), and 1548 PCD-related genes were collected. We used the "limma" package to analyze differentially expressed genes (DEGs). The STRING database was used for protein interaction analysis, and the least absolute shrinkage and selection operator (Lasso) and support vector machines (SVMs) regression analyses were used to identify biomarkers. Then, the timeROC package was used for classifier efficiency assessment, and the "CIBERSORT" package was used for immune infiltration analysis. Wound healing and transwell migration assay were performed to evaluate migration and invasion.

Results: We identified 800 DEGs between our control and NPC patient groups, in which 59 genes appeared to be PCD-related DEGs, with their function closely associated with NPC progression, including activation of the PI3K-Akt, TGF-β, and IL-17 signaling pathways. Furthermore, based on the STRING database, Cytoscape and six algorithms were employed to screen 16 important genes (GAPDH, FN1, IFNG, PTGS2, CXCL1, MYC, MUC1, LTF, S100A8, CAV1, CDK4, EZH2, AURKA, IL33, S100A9, and MIF). Subsequently, two reliably characterized biomarkers, FN1 and MUC1, were obtained from the Lasso and SVM analyses. The Receiver operating characteristic (ROC) curves showed that both biomarkers had area under the curve (AUC) values higher than 0.9. Meanwhile, the enrichment analysis showed that in NPC patients, the FN1 and MUC1 expression levels correlated with programmed cell death-related pathways. The enrichment analysis and cellular experimental results indicated that FN1 and MUC1 were overexpressed in NPC cells and associated with programmed cell death-related pathways. Importantly, FN1 and MUC1 severely affected the ability of NPC cells to migrate, invade, and undergo apoptosis. Finally, medroxyprogesterone acetate and 8-Bromo-cAMP acted as drug molecules for the docking of FN1 and MUC1 molecules, respectively, and had binding capacities of -9.17 and -7.27 kcal/mol, respectively.

Conclusion: We examined the PCD-related phenotypes and screened FN1 and MUC1 as reliable biomarkers of NPC; our findings may promote the development of NPC treatment strategy.

Background: Breast cancer (BC) ranks as the most prevalent malignancy affecting women globally, with apoptosis playing a pivotal role in its pathological progression. Despite the crucial role of apoptosis in BC development, there is limited research exploring the relationship between BC prognosis and apoptosis-related genes (ARGs). Therefore, this study aimed to establish a BC-specific risk model centered on apoptosis-related factors, presenting a novel approach for predicting prognosis and immune responses in BC patients.

Methods: Utilizing data from The Cancer Gene Atlas (TCGA), Cox regression analysis was employed to identify differentially prognostic ARGs and construct prognostic models. The accuracy and clinical relevance of the model, along with its efficacy in predicting immunotherapy outcomes, were evaluated using independent datasets, Receiver Operator Characteristic (ROC) curves, and nomogram. Additionally, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses were used to predict potential mechanical pathways. The CellMiner database is used to assess drug sensitivity of model genes.

Results: A survival risk model comprising eight prognostically relevant apoptotic genes (PMAIP1, TP53AIP1, TUBA3D, TUBA1C, BCL2A1, EMP1, GSN, F2) was established based on BC patient samples from TCGA. Calibration curves validated the ROC curve and nomogram, demonstrating excellent accuracy and clinical utility. In samples from the Gene Expression Omnibus (GEO) datasets and immunotherapy groups, the low-risk group (LRG) demonstrated enhanced immune cell infiltration and improved immunotherapy responses. Model genes also displayed positive associations with sensitivity to multiple drugs, including vemurafenib, dabrafenib, PD-98059, and palbociclib.

Conclusions: This study successfully developed and validated a prognostic model based on ARGs, offering new insights into prognosis and immune response prediction in BC patients. These findings hold promise as valuable references for future research endeavors in this field.

Drosophila melanogaster has been used as a model system to identify and characterize genetic contributions to development, homeostasis, and to investigate the molecular determinants of numerous human diseases. While there exist many differences at the genetic, structural, and molecular level, many signalling components and cellular machineries are conserved between Drosophila and humans. For this reason, Drosophila can and has been used extensively to model, and study human pathologies. The extensive genetic resources available make this model system a powerful one. Over the years, the sophisticated and rapidly expanding Drosophila genetic toolkit has provided valuable novel insights into the contribution of genetic components to human diseases. The activity of Notch signalling is crucial during development and conserved across the Metazoa and has been associated with many human diseases. Here we highlight examples of mechanisms involving Notch signalling that have been elucidated from modelling human diseases in Drosophila melanogaster that include neurodegenerative diseases, congenital diseases, several cancers, and cardiac disorders.