Regulatory function of DNA methylation mediated lncRNAs in gastric cancer.
Ontology highlight
ABSTRACT:
SUBMITTER: Li N
PROVIDER: S-EPMC9270757 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Growing evidence implies a link between DNA methylation and tumor immunity/immunotherapy. However, the global influence of DNA methylation on the characteristics of the tumor microenvironment and the efficacy of immunotherapy remains to be clarified. In this study, we systematically evaluated the DNA methylation regulator patterns and tumor microenvironment characteristics of 1,619 gastric cancer patients by clustering the gene expression of 20 DNA methylation regulators. Three gastric cancer subtypes that had different DNA methylation modification patterns and distinct tumor microenvironment characteristics were recognized. Then, a DNA methylation score (DMS) was constructed to evaluate DNA methylation modification individually. High DMS was characterized by immune activation status, increased tumor mutation burden, and tumor neoantigens, with a favorable prognosis. Conversely, activation of the stroma and absence of immune cell infiltration were observed in the low DMS group, with relatively poor survival. High DMS was also certified to be correlated with enhanced efficacy of immunotherapy in four immune checkpoint blocking treatment cohorts. In conclusion, the characterization of DNA methylation modification patterns may help to enhance our recognition of the tumor immune microenvironment of gastric cancer and guide more personalized immunotherapy strategies in the future.
| S-EPMC8099484 | biostudies-literature
Project description:Colon cancer is the most commonly diagnosed malignancy and the leading cause of cancer deaths worldwide. As well as lifestyle, genetic and epigenetic changes are key factors that influence the risk of colon cancer. However, the impact of epigenetic alterations in non-coding RNAs and their consequences in colon cancer have not been fully characterized. We detected differential methylation sites (DMSs) in long non-coding RNA (lncRNA) promoters and identified lncRNA expression quantitative trait methylations (lncQTMs) by association tests. To investigate how transcription factor (TF) binding was affected by DNA methylation, we characterized the occurrence of known TFs among DMSs collected from the MEME suite. We further combined methylome and transcriptome data to construct TF-methylation-lncRNA relationships. To study the role of lncRNAs in drug response, we used pharmacological and lncRNA profiles from the Cancer Cell Line Encyclopedia (CCLE) and investigated the association between lncRNAs and drug activity. We also used combinations of TF-methylation-lncRNA relationships to stratify patient survival using a risk model. DNA methylation sites displayed global hyper-methylation in lncRNA promoters and tended to have negative relationships with the corresponding lncRNAs. Negative lncQTMs located near transcription start sites (TSSs) had more significant correlations with the corresponding lncRNAs. Some lncRNAs found to be mediated by the interplay between DNA methylation and TFs were previously identified as markers for colon cancer. We also found that the ELF1-cg05372727- LINC00460 relationship were prognostic signatures for colon cancer. These findings suggest that lncRNAs mediated by the interplay between DNA methylation and TFs are promising predictors of drug response, and that combined TF-methylation-lncRNA can serve as a prognostic signature for colon cancer.
| S-EPMC7673839 | biostudies-literature
Project description:The discovery of microRNAs (miRNAs) provides a new and powerful tool for studying the mechanism, diagnosis and treatment of human cancers. Currently, down-regulation of tumor suppressive miRNAs by CpG island hypermethylation is emerging as a common hallmark of cancer. Here, we reported that the down-regulation of miR-33b was associated with pM stage of gastric cancer (GC) patients. Ectopic expression of miR-33b in HGC-27 and MGC-803 cells inhibited cell proliferation, migration and invasion, which might be due to miR-33b targeting oncogene c-Myc. Moreover, enhanced methylation level of the CpG island upstream of miR-33b in GC patients with down-regulated miR-33b was confirmed by methylation-specific PCR (MSP) amplification. Furthermore, re-introduction of miR-33b significantly suppressed tumorigenesis of GC cells in the nude mice. In conclusion, miR-33b acts as a tumor suppressor and hypermethylation of the CpG island upstream of miR-33b is responsible for its down-regulation in gastric cancer.
| S-EPMC4700416 | biostudies-literature
Project description:Background: The prognosis of gastric cancer (GC) patients is poor. The effect of aberrant DNA methylation on FOXF2 expression and the prognostic role of FOXF2 methylation in GC have not yet been identified. Methods: The RNA-Seq and gene methylation HM450 profile data were used for analyzing FOXF2 expression in GC and its association with methylation level. Bisulfite sequencing PCR (BSP) was performed to measure the methylation level of the FOXF2 promoter region in GC cell lines and normal GES-1 cells. The cells were treated with the demethylation reagent 5-Aza-dC, and the mRNA and protein expression levels of FOXF2 were then measured by qRT-PCR and western blot assays. The risk score system from SurvivalMeth was calculated by integrating the methylation level of the cg locus and the corresponding Cox regression coefficient. Results: FOXF2 was significantly downregulated in GC cells and tissues. On the basis of RNA-Seq and Illumina methylation 450 data, FOXF2 expression was significantly negatively correlated with the FOXF2 methylation level (Pearson's R = -0.42, p < 2.2e-16). The FOXF2 methylation level in the high FOXF2 expression group was lower than that in the low FOXF2 expression group. The BSP assay indicated that the methylation level of the FOXF2 promoter region in GC cell lines was higher than that in GES-1 cells. The qRT-PCR and western blot assay showed that FOXF2 mRNA and protein levels were increased in GC cells following treatment with 5-Aza-Dc. The methylation risk score model indicated that patients in the high risk group had poorer survival probability than those in the low risk group (HR = 1.84 (1.11-3.07) and p = 0.0068). FOXF2 also had a close transcriptional regulation network with four miRNAs and their corresponding target genes. Functional enrichment analysis of the target genes revealed that these genes were significantly related to several important signaling pathways. Conclusion: FOXF2 was downregulated due to aberrant DNA methylation in GC, and the degree of methylation in the promoter region of FOXF2 was related to the prognosis of patients. The FOXF2/miRNAs/target genes axis may play a vital biological regulation role in GC.
| S-EPMC8460759 | biostudies-literature
Project description:Current studies indicate that long non-coding RNAs (lncRNAs) are frequently aberrantly expressed in cancers and implicated with prognosis in gastric cancer (GC). We intended to generate a multi-lncRNA signature to improve prognostic prediction of GC. By analyzing ten paired GC and adjacent normal mucosa tissues, 339 differentially expressed lncRNAs were identified as the candidate prognostic biomarkers in GC. Then we used LASSO Cox regression method to build a 12-lncRNA signature and validated it in another independent GEO dataset. An innovative 12-lncRNA signature was established, and it was significantly associated with the disease free survival (DFS) in the training dataset. By applying the 12-lncRNA signature, the training cohort patients could be categorized into high-risk or low-risk subgroup with significantly different DFS (HR = 4.52, 95%CI= 2.49-8.20, P < 0.0001). Similar results were obtained in another independent GEO dataset (HR=1.58, 95%CI=1.05 - 2.38, P=0.0270). Further analysis showed that the prognostic value of this 12-lncRNA signature was independent of AJCC stage and postoperative chemotherapy. Receiver operating characteristic (ROC) analysis showed that the area under receiver operating characteristic curve (AUC) of combined model reached 0.869. Additionally, a well-performed nomogram was constructed for clinicians. Moreover, single-sample gene-set enrichment analysis (ssGSEA) showed that a group of pathways related to drug resistance and cancer metastasis significantly enriched in the high risk patients. A useful innovative 12-lncRNA signature was established for prognostic evaluation of GC. It might complement clinicopathological features and facilitate personalized management of GC.
| S-EPMC5595087 | biostudies-other
Project description:BackgroundFew studies have examined prognostic outcomes-associated molecular signatures other than overall survival (OS) for gastric cancer (GC). We aimed to identify DNA methylation biomarkers associated with multiple prognostic outcomes of GC in an epigenome-wide association study.MethodsBased on the Cancer Genome Atlas (TCGA), DNA methylation loci associated with OS (n = 381), disease-specific survival (DSS, n = 372), and progression-free interval (PFI, n = 383) were discovered in training set subjects (false discovery rates < 0.05) randomly selected for each prognostic outcome and were then validated in remaining subjects (P-values < 0.05). Key CpGs simultaneously validated for OS, DSS, and PFI were further assessed for disease-free interval (DFI, n = 247). Gene set enrichment analyses were conducted to explore the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways simultaneously enriched for multiple GC prognostic outcomes. Methylation correlated blocks (MCBs) were identified for co-methylation patterns associated with GC prognosis. Based on key CpGs, risk score models were established to predict four prognostic outcomes. Spearman correlation analyses were performed between key CpG sites and their host gene mRNA expression.ResultsWe newly identified DNA methylation of seven CpGs significantly associated with OS, DSS, and PFI of GC, including cg10399824 (GRK5), cg05275153 (RGS12), cg24406668 (MMP9), cg14719951(DSC3), and cg25117092 (MED12L), and two in intergenic regions (cg11348188 and cg11671115). Except cg10399824 and cg24406668, five of them were also significantly associated with DFI of GC. Neuroactive ligand-receptor interaction pathway was suggested to play a key role in the effect of DNA methylation on GC prognosis. Consistent with individual CpG-level association, three MCBs involving cg11671115, cg14719951, and cg24406668 were significantly associated with multiple prognostic outcomes of GC. Integrating key CpG loci, two risk score models performed well in predicting GC prognosis. Gene body DNA methylation of cg14719951, cg10399824, and cg25117092 was associated with their host gene expression, whereas no significant associations between their host gene expression and four clinical prognostic outcomes of GC were observed.ConclusionsWe newly identified seven CpGs associated with OS, DSS, and PFI of GC, with five of them also associated with DFI, which might inform patient stratification in clinical practices.
| S-EPMC8152126 | biostudies-literature
Project description:Krüppel-like factor 4 (KLF4) has a tumor suppressor role in the progression of gastric cancer (GC), and inhibition or loss of KLF4 expression was identified in GC. The aim of this study was to explore the new molecular mechanism of KLF4 inactivation in gastric cancer. Herein, we report that Helicobacter pylori infection or Cag pathogenicity island protein A (CagA) gene transduction resulted in KLF4 expression downregulation and promoted gastric epithelial cell and gastric cancel cell proliferation, migration, and colony formation. Mechanistically, we found that CagA gene transduction led to DNA methylation of the KLF4 promoter, an effect that was relevant to the significant downregulation of TET1 expression. Causally, knockdown of TET1 expression decreased KLF4 expression, whereas overexpression of TET1 had the opposite effect. Clinically, we found that KLF4 expression and the 5-hmC levels were lower in GC cells with H pylori infection than in GC cells without H pylori infection. Thus, our study not only sheds new light on how H pylori infection promotes the progression of GC but also elucidates a novel mechanism of KLF4 inactivation in GC pathogenesis. During pathogenesis, an alteration in the H pylori/CagA-TET1-KLF4 signaling pathway plays a critical role, suggesting that this pathway may be a prospective target for gastric carcinoma intervention and therapy.
| S-EPMC7131848 | biostudies-literature
Project description:BACKGROUND: Epigenetic alteration of gene expression is a common event in human cancer. DNA methylation is a well-known epigenetic process, but verifying the exact nature of epigenetic changes associated with cancer remains difficult. METHODS: We profiled the methylome of human gastric cancer tissue at 50-bp resolution using a methylated DNA enrichment technique (methylated CpG island recovery assay) in combination with a genome analyzer and a new normalization algorithm. RESULTS: We were able to gain a comprehensive view of promoters with various CpG densities, including CpG Islands (CGIs), transcript bodies, and various repeat classes. We found that gastric cancer was associated with hypermethylation of 5' CGIs and the 5'-end of coding exons as well as hypomethylation of repeat elements, such as short interspersed nuclear elements and the composite element SVA. Hypermethylation of 5' CGIs was significantly correlated with downregulation of associated genes, such as those in the HOX and histone gene families. We also discovered long-range epigenetic silencing (LRES) regions in gastric cancer tissue and identified several hypermethylated genes (MDM2, DYRK2, and LYZ) within these regions. The methylation status of CGIs and gene annotation elements in metastatic lymph nodes was intermediate between normal and cancerous tissue, indicating that methylation of specific genes is gradually increased in cancerous tissue. CONCLUSIONS: Our findings will provide valuable data for future analysis of CpG methylation patterns, useful markers for the diagnosis of stomach cancer, as well as a new analysis method for clinical epigenomics investigations.
| S-EPMC3273443 | biostudies-literature
Project description:Several studies have found that DNA methylation is associated with transcriptional regulation and affect sponge regulation of non-coding RNAs in cancer. The integration of circRNA, miRNA, DNA methylation and gene expression data to identify sponge circRNAs is important for revealing the role of DNA methylation-mediated regulation of sponge circRNAs in cancer progression. We established a DNA methylation-mediated circRNA crosstalk network by integrating gene expression, DNA methylation and non-coding RNA data of breast cancer in TCGA. Four modules (26 candidate circRNAs) were mined. Next, 10 DNA methylation-mediated sponge circRNAs (sp_circRNAs) and five sponge driver genes (sp_driver genes) in breast cancer were identified in the CMD network using a computational process. Among the identified genes, ERBB2 was associated with six sponge circRNAs, which illustrates its better sponge regulatory function. Survival analysis showed that DNA methylations of 10 sponge circRNA host genes are potential prognostic biomarkers in the TCGA dataset (p = 0.0239) and GSE78754 dataset (p = 0.0377). In addition, the DNA methylation of two sponge circRNA host genes showed a significant negative correlation with their driver gene expressions. We developed a strategy to predict sponge circRNAs by DNA methylation mediated with playing the role of regulating breast cancer sponge driver genes.
| S-EPMC6988805 | biostudies-literature
Project description:Long non-coding RNAs (lncRNAs) have been generally considered to serve important roles in various types of cancer, including gastric cancer. However, a comprehensive understanding of lncRNAs in gastric cancer requires further study. The present study performed an in-depth study revealed 50 differently expressed lncRNAs. The changed cellular pathways and biological process in gastric cancer were determined. To further confirm the functions of the differently expressed lncRNAs, co-expression networks were constructed between the lncRNAs and mRNA; this lead to the identification of 6 modules, which participated in various cellular pathways. In addition, 2 lncRNAs were identified which were associated with clinical outcome. The biological analysis and experimental evidence suggested that LINC00982 inhibited, while LL22NC03-N14H11.1 promoted the proliferation of gastric cancer cells. These lncRNAs may be considered as potential prognostic factor in gastric cancer.
| S-EPMC6313033 | biostudies-literature