Objective To map the genome-wide distribution profile of histone H3K27me3 modification in diffuse gastric cancer tissues,identify target genes regulated by H3K27me3,and primarily explore the potential mechanism of its modification reprogramming in the occurrence and development of the tumor.Methods Normal gastric mucosal tissues and diffuse gastric cancer tissues were harvested from the patients who underwent examinations or treatments in the departments of gastroenterology and gastrointestinal surgery of our medical center between 2021 and 2023.There were 14 patients in the normal group(6 males and 8 females,average age of 46 years)and 14 patients in the gastric cancer group(8 males and 6 females,average age of 63 years).Cleavage under target and tagmentation(CUT&Tag)technology was employed to capture genomic regions modified by H3K27me3,and analyze the reprogramming characteristics of these modifications.RNA sequencing data,data from high-throughput chromosome conformation capture(Hi-C)technology,and publicly available single-cell data were integrated to investigate the target genes regulated by the reprogramming of H3K27me3 modifications in diffuse gastric cancer cells.Results The quality of the CUT&Tag and RNA sequencing data met the standards required for subsequent analysis.Histone H3K27me3 modifications in normal gastric mucosa and diffuse gastric cancer tissues were primarily distributed in distal intergenic regions and intronic regions.In gastric cancer tissues,compared to normal tissues,there was significant reprogramming of H3K27me3 modifications,characterized by a marked reduction in overall H3K27me3 signal intensity.The loss of 2 912 H3K27me3 signal peaks might lead to the up-regulation of 822 tumor-associated genes.Among them,56 genes displayed the most significant up-regulation(fold change in signal intensity≥2,P<0.05),with notable enrichment in the mammalian target of rapamycin complex 1(mTORC1)signaling pathway.Specifically,the methionine transporter SLC7A5 and the cystine transporter SLC7A11 were found to have the highest expression levels in gastric cancer tissues.Single-cell data revealed that the abnormal overexpression of SLC7A11 in diffuse gastric cancer was primarily observed in tumor epithelial cells.Further validation using public data and immunohistochemical experiments confirmed the elevated expression of SLC7A11 in diffuse gastric cancer,which is associated with poor prognosis in gastric cancer patients.Conclusion The reprogramming of histone H3K27me3 modification is an important epigenetic characteristic in diffuse gastric cancer.Loss of H3K27me3 signal peaks may up-regulate the expression of SLC7A11 in diffuse gastric cancer cells,and thereby promote tumor progression.

Objective To map the super-enhancers remodeling of intestinal gastric cancer and reveal the tumor biological functions of the super-enhancers and the downstream target genes that may be activated.Methods A total of 31 normal gastric mucosal tissues,23 intestinal gastric cancer tissues and 9 intestinal gastric cancer organoids were collected from the Department of Gastroenterology of Army Medical Center of PLA from January to December 2022.Chromatin targeting histone H3K27ac modified chromatin targeting cleavage under targets and tagmentation(CUT&Tag)sequencing was conducted on above tissues.The remodeling profiles of super-enhancers in intestinal gastric cancer were analyzed and the key target genes were identified based on bioinformation tools.CRISPRi technology was used to intervene with the super-enhancers,the expression of target genes was detected with Western blotting,and the proliferation,migration and invasion abilities were detected by CCK-8 assay and Transwell chambers in the control group and the intervention group.Results There was a significant difference in the signal of super-enhancers between intestinal gastric cancer tissues and normal gastric mucosal tissues(P<0.05),and the active super-enhancers in cancer tissues may be involved in biological processes such as negative regulation of the immune system and cell adhesion.The expression of up-regulated cell migration-inducing protein(CEMIP)in tumor cells was regulated by the super-enhancers,and intervening the super-enhancers down-regulated the expression of CEMIP(P<0.05),and inhibited the cell proliferation,invasion and migration abilities of tumor cells(P<0.05).Conclusion Super-enhancer remodeling is observed in intestinal gastric cancer,and they can up-regulate the expression of CEMIP gene and promote the growth,migration and invasion of cancer cells.

Objective To draw the genome-wide distribution and remodeling characteristics of H3K27me3 silencers in signet-ring cell carcinoma of the stomach(SRCC)through epigenetic sequencing technology,and to investigate their roles in transcriptional regulation in order to elucidate the regulatory mechanism of SRCC malignant progression.Methods The study was conducted on 35 gastric samples obtained by gastroendoscopic biopsy(15 normal and 20 SRCC tissues)from Department of Gastroenterology of Army Medical Center of PLA between January 2021 and December 2023.Multi-omics analyses,including assay for transposase-accessible chromatin with high-throughput sequencing(ATAC-seq),cleavage under targets and tagmentation(CUT&Tag)and transcriptome sequencing(RNA-seq),were performed to identify chromatin accessibility,H3K27me3 silencer regions,and transcriptional changes,with aid of Illumina NovaSeq 6000.H3K27me3 related differentially expressed genes(|Log2FC|>1,FDR<0.05)were screened using DESeq2.Gene Ontology(GO)analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis were employed to analyze the enrichment function,and Homer was employed to identify transcription factor motifs.A regulatory network was constructed using Cytoscape,and then validated using immunohistochemistry to explore its regulatory mechanism.Results H3K27me3 silencers were primarily located in distal intergenic regions(37.06%)in SRCC.Compared with the normal tissues,SRCC showed a significant reduction in H3K27me3 silencer signals(95%CI:1.34～2.30,P=0.007)with 6 257 lost sites(FDR<0.01).Integrating CUT&Tag and RNA-seq revealed 380 up-regulated immune-related genes,particularly in T cell receptor signaling(OR=4.2,95%CI:2.8～6.3,P=0.002).Immunohistochemistry confirmed elevated expression of transcription factor EHF(P<0.05).Conclusion There is the remodeling of H3K27me3 silencers in SRCC,and EHF may potentially play a crucial role in the SRCC malignant progression.

Objective To identify the enhancer profile marked by histone H3K27ac modification in high-grade intraepithelial neoplasia(HGIN)in order to reveal the novel regulatory mechanism of HGIN pathogensis.Methods Gastric tissue samples were collected from Department of Gastroenterology of Army Medical Center of PLA between June 2022 and June 2023,including 14 normal gastric tissues(Nor group),31 HGIN tissues(HGIN group)and 17 gastric cancer tissues(GC group).Cleavage under targets and tagmentation(CUT&Tag)technique was employed to capture enhancer regions modified by histone H3K27ac.Multi-omics analysis was performed to identify HGIN-specific active enhancers and their potentially regulated genes.Immunohistochemical profiling was performed to assess differential expression of the gene of interest across clinically stratified specimens,combined with CRISPR-dCas9-mediated ablation of active enhancers to monitor the gene of interest transcriptional dynamics and validate enhancer-mediated regulatory mechanisms.Results Epigenomic sequencing obtained the data with excellent quality,and indicated that obvious remodeling was observed in H3K27ac enhancers in HGIN and GC groups(P<0.05),though no significant difference in the genome-wide distribution of H3K27ac modification among the 3 groups.Combining transcriptome data revealed that enhancer remodeling may up-regulate the expression of the proliferation-related target gene,CD24,in the HGIN tissue;while,inhibiting enhancer activity can notably reduce CD24 expression level(P<0.05).Immunohistochemical assay displayed a positive correlation between the expression levels of CD24 and Ki-67(P<0.001).Conclusion The remodeling of H3K27ac enhancer represents a significant epigenetic feature of the transformation from normal condition to HGIN.Remodeling of H3K27ac enhancer up-regulates CD24,which may facilitate the abnormal proliferation of gastric epithelial cells.

Objective To analyze clinical characteristics of mesenchymal-subtype gastric cancer(Mes-GC)by integrating multi-omics data and explore the characteristics of tumor cells and microenvironment associated with the risk for recurrence.Methods Gastric tumor tissue samples were collected from the patients who visited Department of Gastroenterology of Army Medical Center of PLA from January 2022 to December 2023.Transcriptome and genome sequencing were applied for these tissue samples,including 19 cases of diffuse-type gastric cancer,22 cases of intestinal-type gastric cancer,and 23 cases of mixed-type gastric cancer patients.Bioinformatics analysis was employed to investigate the differences in clinical characteristics and tumor microenvironment between Mes-GC and non-mesenchymal-subtype gastric cancer(non-Mes-GC)by integrating data resources including The Cancer Genome Atlas(TCGA),Gene Expression Omnibus(GEO),and National Genomics Data Center(NGDC).Results Compared to non-Mes-GC patients,Mes-GC ones were characterized by later clinical stages,deeper tumor infiltration,and higher rates of lymph node metastasis.Kaplan-Meier survival analysis confirmed that Mes-GC patients were associated with shorter survival time,poor prognosis as well as increased risk of cancer recurrence(P<0.05).Single-cell RNA sequencing data revealed that tumor cells in Mes-GC showed higher expression levels of the genes related to stemness,metastasis(P<0.05),and epithelial-mesenchymal transition(EMT).And in the tumor microenvironment,there were significant more myeloid cells,smooth muscle cells,endothelial cells and fibroblasts,with the most pronounced elevation in the proportion of fibroblasts(P<0.05).Moreover,the patients with larger proportion of fibroblasts were associated with poorer prognosis.Conclusion Mes-GC tumor cells exhibit higher stemness and EMT characteristics,and stromal cells such as myeloid cells,endothelial cells,and fibroblasts are enriched in the tumor microenvironment.These features may be key factors contributing to poor prognosis and high recurrence rate of Mes-GC.

Objective To identify the enhancer landscape marked by histone H3K27ac modifications in diffuse-type gastric cancer(DGC)tissues,and to elucidate the epigenetic remodeling mechanisms by which active enhancers regulate cachexia-related genes.Methods Gastric mucosal tissue samples were collected from Department of Gastroenterology of Army Medical Center of PLA during January 2022 to March 2023,including 10 normal gastric mucosa tissues(Normal group),10 DGC tissues diagnosed with cachexia(DGC group),and 10 organoids derived from DGC tissues(Organoid group).Using H3K27ac chromatin targeting cleavage and tagmentation(CUT&Tag)technology,genomic modification regions were captured to screen specific active enhancers and their potential target genes in DGC tissues.CRISPR-dCas9 gene editing technology was used to intervene with the enhancers,and the expression of target genes was detected with Western blotting and qRT-PCR.Sixteen female SPF-grade BALB/c Nude mice(6～8 weeks old,weighing 18～21 g)were utilized to establish an orthotopic xenograft tumor model using the human diffuse-type gastric cancer cell line MKN45.Cachexia-related phenotypes were evaluated in 3 groups:normal group(n=4),silencing group(n=6),and control group(n=6).Results Significant differential enhancer regions were identified between DGC and normal gastric mucosa tissues.DGC tissues exhibited a marked increase in enhancer abundance(P<0.05)and signal intensity when compared with the normal counterparts.Integrated analysis of transcriptome data revealed that some of these active enhancers up-regulated the expression of GDF15,a cachexia-associated target gene in DGC.Targeted silencing of the active enhancer of GDF15 using CRISPR/dCas9-KRAB plasmid technology resulted in a significant reduction in GDF15 expression at both mRNA levels(P<0.05)and protein.Results from orthotopic transplantation experiments of DGC demonstrated that silencing of active enhancers alleviated the cachexia phenotype in nude mice(P<0.05).Conclusion DGC exhibits enhancer remodeling,which regulates the expression of the cachexia-associated gene GDF15,and thereby contributes to the pathogenesis and progression of cancer cachexia.

Objective To explore the genome-wide distribution of histone H3K27ac in intestinal type gastric cancer,analyze remodeling features of enhancers and regulome and construct a prediction model for prognosis.Methods H3K27ac CUT&Tag sequencing and RNA sequencing were performed in intestinal type gastric cancer tissues from 15 patients and normal gastric mucosa tissues from 18 healthy volunteers.Bioinformatics analysis was performed to identify the differences in genome distribution of H3K27ac modifications.Based on the distribution characteristics of H3K27ac,the enhancer elements were identified and the remodeling characteristics of enhancer and related regulome were explored.The prediction model for prognosis based on enhancer related target genes was constructed by univariate Cox and multivariate Cox regression analyses.Results The histone H3K27ac modification was mainly distributed in the enhancer region and displayed no significant differences in the genomic distribution patterns between normal and cancer tissues.Compared with normal gastric mucosa,the level of enhancer H3K27ac modification was higher in intestinal type gastric cancer.A total of 8847 enhancers with increased activity in intestinal type gastric cancer were identified,accounting for 8.3%of all enhancers,which might promote malignant behaviors such as proliferation and adhesion of gastric cancer cells.A prognosis-predicting model established based on a panel of 6 genes that upregulated by the acquired enhancer in cancers,which was able to predict the overall survival of patients.Conclusion Enhancer remodeling is one of the significant epigenetic features of intestinal type gastric cancer.These enhancers may drive malignant growth and adhesion of cancer cells by upregulating the expression of MYC,E2F3 and other genes.A prognosis model based on enhancer target genes is constructed.

Objective·To analyze the expression of mitochondrial related gene SFXN3(sideroflexin 3)in head and neck squamous cell carcinoma(HNSCC)and its effect on cell proliferation.Methods·Mitochondrial related genes and TCGA-HNSCC dataset were obtained from public databases to identify the target gene SFXN3 by using bioinformatic methods.The expression of SFXN3 in HNSCC patient samples was analysed by using the UALCAN database,and survival analyses of patients with different SFXN3 expression levels were performed according to TCGA-HNSCC cohort and GEO cohorts(GSE65858,GSE41613 and GSE27020).By using TCGA-HNSCC cohort and GEO cohorts(GSE40020,GSE210287),the differences in SFXN3 expression levels between therapeutic responders and non-responders were compared.Quantitative real-time PCR(qRT-PCR)was used to verify the expression of SFXN3 in the collected HNSCC tumor and para-tumor tissues,and the expression level of SFXN3 in human normal oral epithelial cells and HNSCC tumor cell lines was detected.With the construction of stable-SFXN3-knockdown HNSCC cell lines,the effect of SFXN3 on the proliferation ability of HNSCC cells was observed by using the Incucyte live-cell imaging analysis system and plate colony formation assay.Transcriptome sequencing was performed on the total RNA of stably-SFXN3-knockdown cells and control cells,and pathway enrichment analysis was performed on the genes with differentially down-regulated expression in knockdown group compared with control group.Results·SFXN3 was highly expressed in tumor tissues of HNSCC patients(P=0.000),and the prognosis of patients in the SFXN3-high-expression group was poor(all P＜0.05).The expression level of SFXN3 in the non-responders was higher than that in the responders(P=0.008),indicating an unfavorable prognosis.High expression of SFXN3 was verified in the collected HNSCC tumor tissues and HNSCC cell lines(all P＜0.05).After the knockdown of SFXN3 expression,the proliferation ability of HNSCC cells decreased,and the number of plate clones decreased(all P＜0.05).RNA sequencing showed that the differentially expressed down-regulated genes in HNSCC cells in the SFXN3-knockdown group were enriched in DNA replication,cell cycle,mitochondrial translation,mitochondrial RNA metabolic process and mitochondrial gene expression pathways.Conclusion·SFXN3 is highly expressed in HNSCC and it has negative correlation with the prognosis of patients.The proliferation ability and plate colony formation ability are inhibited in SFXN3-knockdown HNSCC cells,and these may work by affecting mitochondria function.

In order to improve the quality of teaching, the teaching and research section of parasitology explores the teaching effects of human parasitology based on independent learning. Taking the clinical medicine specialty (excellent doctor class) as an example, in order to overcome the problems that the teaching content brought by traditional infusion teaching is difficult to meet the needs of modern teaching and students have low interest in learning. On the basis of optimizing teaching content and teaching methods, some courses are adopted flipped classroom teaching model based on the MOOC videos learning before class, emphasizing student-centered and self-directed learning, focusing on independent learning ability and critical thinking training, and introducing modern information technology and improving teaching effectiveness. The teaching effect shows that the student-centered teaching thought can be better reflected, students' ability of self-learning has been enhanced, and their sense of learning achievement has been strengthened, in favor of cultivating their ability to analyze and solve problems, as well as lifelong learning ability and teamwork ability.

Objective:To establish the prokaryotic expression system of Taenia solium (Ts) 14-3-3.2, and observe the expression of Ts14-3-3.2 protein at the stages of Ts adult and cysticercus. Methods:Based on the Ts14-3-3.2 gene sequence obtained by the Department of Parasitology, Zunyi Medical University in the previous study, the whole gene was synthesized by PCR-based accurate synthesis (PAS) method. After double digestion with restriction enzymes Nde Ⅰ and Xba Ⅰ, the plasmid pCzn1 was ligated to construct a recombinant plasmid pCzn1-Ts14-3-3.2. Then it was transformed into Escherichia coli ArcticExpress competent cells to induce the expression of Ts14-3-3.2 protein. The expression products were analyzed and identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and coomassie blue staining. The purified Ts14-3-3.2 recombinant protein was obtained by Ni-affinity chromatography. New Zealand rabbits were immunized with the recombinant protein to produce Ts14-3-3.2 polyclonal antibody. Western blotting was used to detect the expression of Ts14-3-3.2 protein at the stages of Ts adult and cysticercus. Results:The recombinant plasmid pCzn1-Ts14-3-3.2 was successfully constructed. After induced expression, Ts14-3-3.2 target protein bands appeared in the supernatant and precipitated at the relative molecular weight of about 29.31 × 10 3. The purified Ts14-3-3.2 recombinant protein with His label could be recognized by anti-His monoclonal antibody, and the Ts14-3-3.2 polyclonal antibody with titer of 1 ∶ 512 000 was obtained. Western blotting showed that Ts14-3-3.2 protein was expressed at the stages of Ts adult and cysticercus. Conclusions:The prokaryotic expression system of Ts14-3-3.2 is successfully established, and the Ts14-3-3.2 polyclonal antibody with relatively higher purity and titer is obtained. The Ts14-3-3.2 protein is expressed at the stages of Ts adult and cysticercus.