Identification of necroptosis-associated miRNA signature for predicting prognosis and immune landscape in stomach adenocarcinoma.

PURPOSE: This study aims to identify the potential necroptosis related genes (NRGs)-associated miRNAs signature and explore the impact on the prognosis of stomach adenocarcinoma (STAD). METHODS: Employing rigorous methodologies, we utilized univariate Cox, Lasso and multivariate Cox regression analyses to develop a prognostic signature. Kaplan-Meier (K-M) and ROC curves were applied to assess the prognostic value of signature in a training group and an independent test group. Furthermore, we conducted Gene Set Enrichment Analysis (GSEA) for enrichment of tumor-related pathways. The risk score was calculated for each patient based on the expression of miRNAs which were enrolled in the signature. Patients were stratified into high- and low-risk groups. The immune cell infiltration and immunotherapy were compared between the two groups. Finally, the diagnostic potential of the miRNA was explored by RT-qPCR. RESULTS: We constructed a prognostic model based on 6 NRGs-associated miRNAs. K-M plots underscored superior survival outcomes in the low-risk group. GSEA results revealed the enrichment of several tumor-related pathways in the high-risk group. Notably, CD8+ T cells, Tregs and activated memory CD4+ T cells exhibited negative correlations with the risk score. Additionally, a few immune checkpoint genes, such as CTLA4, PD1 and PD-L1, were significantly upregulated in the low-risk group. Furthermore, the serum expression levels of all these 6 miRNAs were significantly elevated in STAD patients. CONCLUSIONS: Our study identified a robust risk score derived from a signature of 6 NRGs-associated miRNAs, demonstrating high efficacy for prognosis of STAD. These results not only contributed to our understanding of STAD pathogenesis, but also held promise for potential clinical applications, particularly in the realm of personalized immunotherapy for STAD patients.

Fusobacterium Nucleatum Is a Risk Factor for Metastatic Colorectal Cancer.

OBJECTIVE: Increasing evidence has indicated that there is a correlation between Fusobacterium nucleatum (F. nucleatum) abundance and poor prognosis of colorectal cancer (CRC). Furthermore, tumor metastasis plays a decisive role in the prognosis of CRC patients. Therefore, it was hypothesized that the abundance of F. nucleatum in CRC tissues affects the tumor metastasis. METHODS: In the present study, F. nucleatum DNA obtained from 141 resected CRC samples was quantified by qPCR to determine whether there were differences in F. nucleatum abundance between groups with and without CRC metastasis. RESULTS: The results revealed that F. nucleatum was more abundant in CRC patients with metastasis, and CRC tissues enriched with F. nucleatum had a higher risk of lymph node metastasis and distant metastasis. The receiver operating characteristic curve indicated that F. nucleatum in CRC tissues could be used as an indicator for CRC metastasis, to some extent. Furthermore, the in vitro experiments (electron microscopy, and migration and invasion trials) revealed that F. nucleatum was a highly invasive bacterial strain, and could significantly enhance the invasion and migration capacity of SW480 and SW620 cells. In addition, a meta-analysis comprehensively indicated a slight correlation between F. nucleatum abundance and advanced CRC stage (RR=1.17, 95% CI: 1.00-1.37, P=0.04, random effect). CONCLUSION: There is a correlation between F. nucleatum abundance and CRC metastasis, and F. nucleatum may serve as a metastasis biomarker for CRC patients.

The Application Value of Syndecan-2 Gene Methylation for Colorectal Cancer Diagnosis: A Clinical Study and Meta-Analyses.

Objective: Syndecan-2 (SDC2) methylation has been previously reported as a sensitive biomarker for the early detection of colorectal cancer (CRC). Droplet digital PCR (ddPCR) is the latest development of PCR technology. It can accurately detect and quantify the target sequence of nucleic acid. ddPCR is widely used in research and clinical diagnosis. In the present study, we aimed to develop a ddPCR method to detect SDC2 gene methylation and evaluate the diagnostic value of SDC2 gene methylation. Methods: First, a ddPCR method was developed to measure SDC2 methylation in stool samples collected from 51 cases of normal, 23 cases of adenoma, and 86 cases of CRC. Subsequently, a meta-analysis of existing studies was conducted to judge the diagnostic value of SDC2 gene methylation in CRC. PUBMED, EMBASE, Web of Science, and Scopus databases were searched for relative studies. Meta-analysis was performed using Meta Disc 1.4 and STATA 15.0 software. Results: The ddPCR showed that the linearity, sensitivity, and specificity for the detection of SDC2 gene methylation could be down to 0.1% methylation level and 5 ng of methylated DNA input. In 109 cases of CRC, 107 cases could be detected, and the sensitivity was 98.17%. The median value of the percentage of methylated reference (PMR) in colorectal adenoma and CRC patients was significantly higher compared with the normal individuals (p < 0.001). In addition, we found that the PMR value was associated with the clinical staging of CRC. The difference of PMR in stage II and stage IIIA was statistically significant (p < 0.05). Moreover, the meta-analysis showed that 11 out of 87 studies were identified to report the feasibility of SDC2 gene methylation as a method to diagnose early CRC. The pooled sensitivity and specificity of SDC2 gene methylation test for CRC were 0.80 [95% CI (0.68-0.88)] and 0.93 [95% CI (0.91-0.94)], respectively. The pooled diagnostic odds ratio (DOR) and area under curve (AUC) were 52.46 [95% CI (30.43-90.45)] and 0.94 [95% CI (0.92, 0.96)], respectively. Conclusions: The ddPCR method was more sensitive and convenient to detect SDC2 gene methylation, and the pooled analysis showed that methylated SDC2 was a valuable biomarker for the non-invasive detection of CRC.

Comprehensive characterization of 11 prognostic alternative splicing events in ovarian cancer interacted with the immune microenvironment.

Alternative splicing (AS) events play a crucial role in the tumorigenesis and progression of cancer. Transcriptome data and Percent Spliced In (PSI) values of ovarian cancer patients were downloaded from TCGA database and TCGA SpliceSeq. Totally we identified 1472 AS events that were associated with survival of ovarian serous cystadenocarcinoma (OC) and exon skipping (ES) was the most important type. Univariate and multivariate Cox regression analysis were performed to identify survival-associated AS events and developed the prognostic model based on 11-AS events. The immune cells and different response to cytotoxic T lymphocyte associated antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1) blockers in low-risk and high-risk group of OC patients were analyzed. Ten kinds of immune cells were found up-regulated in low-risk group. Activated B cell, natural killer T cell, natural killer cell and regulatory T cell were associated with survival of OC. The patients in low-risk group had good response to CTLA-4 and PD-1 blockers treatment. Moreover, a regulatory network was established according to the correlation between AS events and splicing factors (SFs). The present study provided valuable insights into the underlying mechanisms of OC. AS events that were correlated with the immune system might be potential therapeutic targets.

Decreased CXCR2 expression on circulating monocytes of colorectal cancer impairs recruitment and induces Re-education of tumor-associated macrophages.

Though circulating monocytes are the main source of tumour-associated macrophages (TAMs), the regulatory mechanisms of their recruitment to tumours and further differentiation remain unclear. In the present study, we observed a significant decrease in CXCR2 expression in classical circulating monocytes of patients with colorectal cancer (CRC), particularly those in the late TNM stage. The percentage of CXCR2+ monocytes was negatively associated with systemic inflammatory markers and positively associated with intratumoural immunocyte infiltration. The pro-inflammatory cytokine IFN-γ, which was overexpressed in patients with CRC, down-regulated CXCR2 expression of monocytes/TAMs by promoting GRK-2 expression. In vitro, inhibition of CXCR2 signalling in monocytes led to impaired chemotaxis to the tumour cell line supernatant and lower responsiveness to lipopolysaccharide (LPS) stimulation. Finally, monocytes from patients with CRC with decreased CXCR2 expression showed distinct phenotypes and functions after differentiating into CRC cell line-educated TAMs, including expression of co-stimulatory factors and secretion profile, than those from healthy controls. GRK-2 inhibitor altered the functional characteristics of TAMs. In summary, our findings suggest that CXCR2 expression on circulating monocytes reflects CRC stages and is an important factor determining TAM composition in the tumour microenvironment.

Roles of exosomes in diagnosis and treatment of colorectal cancer.

Exosomes are extracellular vesicles that mediate intercellular communication. They contain different molecules, such as DNA, RNA, lipid, and protein, playing essential roles in the pathogenesis of colorectal cancer (CRC). Exosomes derived from CRC are implicated in tumorigenesis, chemotherapy resistance, and metastasis. Besides, they can enhance CRC progression by increasing tumor cell proliferation, reducing apoptosis mechanistically through altering particular essential regulatory genes, or controlling several signaling pathways. Therefore, exosomes derived from CRC are essential biomarkers and can be used in the diagnosis. Indeed, it is crucial to understand the role of exosomes in CRC, which is necessary to develop diagnostic and therapeutic strategies for early detection and treatment. In the present review, we discuss the roles of exosomes in the diagnosis and treatment of CRC.

Clinical value of lncRNA CCAT1 in serum extracellular vesicles as a potential biomarker for gastric cancer.

Long non-coding RNAs (lncRNAs) in extracellular vesicles (EVs) are considered to be novel non-invasive biomarkers for gastric cancer (GC). lncRNA colon cancer-associated transcript 1 (CCAT1) is aberrantly expressed in certain types of cancer. However, the role of EV lncRNA CCAT1 in patients with GC remains unclear. The current study aimed to assess the expression levels of lncRNA CCAT1 in the serum EVs of patients with GC and evaluate its potential clinical value. EVs were isolated from serum using a commercial kit and ultracentrifugation, and were identified by transmission electron microscopy, nanoparticle tracking analysis and western blotting. Serum EV lncRNA CCAT1 levels in patients with GC, chronic gastritis or atypical hyperplasia and healthy control subjects were detected by reverse transcription-quantitative PCR. Additionally, lncRNA CCAT1 was detected in GC and adjacent non-cancerous tissue samples. Serum EVs were successfully isolated and identified in all patients. The results revealed that serum EV lncRNA CCAT1 levels in patients with GC were significantly higher compared with those in healthy controls, patients with chronic gastritis or atypical hyperplasia (all P<0.05). Additionally, EV lncRNA CCAT1 expression levels were significantly different among various groups based on the depth of invasion, distant metastasis and the Tumor-Node-Metastasis stage. The area under the curve (AUC) value of EV lncRNA CCAT1 was 0.890 [95% confidence interval (CI), 0.826-0.937] with 79.6% sensitivity and 92.6% specificity. The combination of EV lncRNA CCAT1 and carcinoembryonic antibody produced an AUC value of 0.910 (95% CI, 0.849-0.951) with the sensitivity and specificity of 80.5 and 92.6%, respectively. In addition, lncRNA CCAT1 was determined to be stable in serum EVs. The expression levels of lncRNA CCAT1 in GC tissue were positively correlated with those in serum EVs, and high levels of lncRNA CCAT1 were associated with a low disease-free survival rate in patients with GC. The results of the present study demonstrated that serum EV lncRNA CCAT1 levels were upregulated in patients with GC compared with those healthy subjects and patients with other illnesses, and may therefore be used as a novel biomarker for this type of cancer.