Identification and Comprehensive Prognostic Analysis of a Novel Chemokine-Related lncRNA Signature and Immune Landscape in Gastric Cancer

Gastric cancer (GC) is a malignant tumor with poor survival outcomes. Immunotherapy can improve the prognosis of many cancers, including GC. However, in clinical practice, not all cancer patients are sensitive to immunotherapy. Therefore, it is essential to identify effective biomarkers for predicting the prognosis and immunotherapy sensitivity of GC. In recent years, chemokines have been widely reported to regulate the tumor microenvironment, especially the immune landscape. However, whether chemokine-related lncRNAs are associated with the prognosis and immune landscape of GC remains unclear. In this study, we first constructed a novel chemokine-related lncRNA risk model to predict the prognosis and immune landscape of GC patients. By using various algorithms, we identified 10 chemokine-related lncRNAs to construct the risk model. Then, we determined the prognostic efficiency and accuracy of the risk model. The effectiveness and accuracy of the risk model were further validated in the testing set and the entire set. In addition, our risk model exerted a crucial role in predicting the infiltration of immune cells, immune checkpoint genes expression, immunotherapy scores and tumor mutation burden of GC patients. In conclusion, our risk model has preferable prognostic performance and may provide crucial clues to formulate immunotherapy strategies for GC.

Ferroptosis Regulators and Tumor Microenvironment Immune Cell Infiltration Characterization in Adrenocortical Carcinoma

Background Adrenocortical carcinoma (ACC) is a rare disease with a poor prognosis and lacking effective systemic treatment options. Recent studies showed that ferroptosis play a prominent role in the initiation and development of cancer. Nonetheless, the potential roles of ferroptosis regulators in the prognosis and tumor microenvironment immunomodulator factors expression remain not fully study. Methods TCGA and GEO ACC datasets were used to investigate the relationship between ferroptosis regulators with prognosis and clinical features. Consensus clustering analysis was performed to divided ACC patients into different ferroptosis subgroups. A ferroptosis scoring system was established for individual ACC using principal component analysis algorithms. The correlation between ferroptosis score and tumor microenvironment immune cell infiltration was analyzed. Results Twenty ferroptosis regulators were differentially expressed in ACC and 17 ferroptosis regulators were closely related to the prognosis of ACC. Three ferroptosis subgroups (Cluster A, B, and C) were determined based on the expression of ferroptosis regulators. Cluster C is preferentially associated with favorable OS, PFS, upregulated antigen-presenting genes expression, and higher immune cell infiltration. GSEA also indicated that Cluster C was prominently related to immune fully activation including chemokine signaling pathway, natural killer cell-mediated cytotoxicity, T cell receptor signaling pathway, and Toll-like receptor signaling pathway. A ferroptosis scoring system was constructed and it could serve as an independent prognostic factor for ACC. The ferroptosis scores were significantly correlated with TMB, immune-checkpoint genes expression, and tumor microenvironment immune cell infiltration in ACC. Further analyses indicated that the ferroptosis score integrated with TMB, immune-checkpoint genes expression, and CD4+ T cell infiltration, could predict the prognosis of ACC. Furthermore, a nomogram was constructed to monitor the prognosis of individual ACC patient. RNA isolation and reverse transcription‑quantitative PCR (RT-qPCR) demonstrated significant differences in the expression levels of ACSL4, FANCD2 and SLC7A1 between ACC and normal tissues. Conclusion Our study demonstrated ferroptosis regulators were significantly associated with the prognosis, clinical characteristics, immune-checkpoint genes expression, and tumor microenvironment immune cell infiltration in ACC. This current study provided comprehensive evidence for further research on ferroptosis regulators in ACC and provides new enlightenment for epigenetic regulation of antitumor immune response.

Identification of an at-risk subpopulation with high immune infiltration based on the peroxisome pathway and TIM3 in colorectal cancer

Background Peroxisomes are pivotal metabolic organelles that exist in almost all eukaryote cells. A reduction in numbers and enzymatic activities of peroxisomes was found in colon adenocarcinomas. However, the role of peroxisomes or the peroxisome pathway in colorectal cancer (CRC) is not defined. Methods In the current study, a peroxisome score was calculated to indicate the activity of the peroxisome pathway using gene set variant analysis based on transcriptomic datasets. CIBERSORTx was chosen to infer enriched immune cells for tumors among subgroups. The SubMap algorithm was applied to predict its sensitivity to immunotherapy. Results The patients with a relatively low peroxisome score and high level of T-cell immunoglobulin and mucin domain 3 (TIM-3) presented the worse overall survival than others. Moreover, low peroxisome scores were associated with high infiltration of lymphocytes and poor prognosis in those CRC patients. Thus, a PERLowTIM3High CRC risk subpopulation was identified and characterized by high immune infiltration. The results also showed that CD8 T cells and macrophages highly infiltrated tumors of the PERLowTIM3High group, regardless of consortium molecular subtype and microsatellite instability status. This subgroup had the highest tumor mutational burden and overexpression of immune checkpoint genes. Further, the PERLowTIM3High group showed a higher probability of responding to programmed cell death protein-1-based immunotherapy. In addition, genes involved in peroxisomal metabolic processes in CRC were also investigated since peroxisome is a rather pleiotropic and highly metabolic organelle in cell. The results indicated that only those genes involved in fatty acid alpha oxidation could be used to stratify CRC patients as similar as peroxisome pathway genes. Conclusions We revealed the favorable prognostic value of the peroxisome pathway in CRC and provided a new CRC stratification based on peroxisomes and TIM3, which might be helpful for CRC diagnostics and personalized treatment.

Adaptive Immune Response Signaling Is Suppressed in Ly6Chigh Monocyte but Upregulated in Monocyte Subsets of ApoE-/- Mice — Functional Implication in Atherosclerosis

RationaleInflammatory monocyte (MC) subset differentiation is a major feature in tissue inflammatory and atherosclerosis. The underlying molecular mechanism remains unclear.ObjectiveThis study aims to explore molecule targets and signaling which determinate immunological features in MC subsets.Methods and ResultsBlood Ly6Chigh and Ly6Clow MC subsets from control and ApoE-/- mice were isolated by flow cytometry sorting and subjected for bulk high-throughput RNA-sequencing. Intensive bioinformatic studies were performed by analyzing transcriptome through four pairs of comparisons: A) Ly6Chigh vs Ly6Clow in control mice; B) Ly6Chigh vs Ly6Clow in ApoE-/- mice; C) ApoE-/- Ly6Chigh vs control Ly6Chigh MC; D) ApoE-/- Ly6Clow vs control Ly6Clow MC. A total of 80 canonical pathways and 16 enriched pathways were recognized by top-down analysis using IPA and GSEA software, and further used for overlapping analysis. Immunological features and signaling were assessed on four selected functional groups, including MHCII, immune checkpoint, cytokine, and transcription factor (TF). Among the total 14578 significantly differentially expressed (SDE) genes identified though above four comparison, 1051 TF and 348 immunological genes were discovered. SDE immunological genes were matched with corresponding upstream SDE TF by IPA upstream analysis. Fourteen potential transcriptional axes were recognized to modulate immunological features in the Ly6C MC subset. Based on an intensive literature search, we found that the identified SDE immune checkpoint genes in Ly6Chigh MC are associated with pro-inflammatory/atherogenic balance function. Immune checkpoint genes GITR, CTLA4, and CD96 were upregulated in Ly6Clow MC from all mice and presented anti-inflammatory/atherogenic features. Six cytokine genes, including Ccl2, Tnfsf14, Il1rn, Cxcl10, Ccl9, and Cxcl2, were upregulated in Ly6Chigh MC from all mice and associated with pro-inflammatory/atherogenic feature. Cytokine receptor gene Il12rb2, Il1r1, Il27ra, Il5ra, Ngfr, Ccr7, and Cxcr5 were upregulated in Ly6Clow MC from all mice and presented anti-inflammatory/atherogenic features. MHCII genes (H2-Oa, H2-DMb2, H2-Ob, H2-Eb2, H2-Eb1, H2-Aa, and Cd74) were elevated in Ly6Clow MC from all mice. ApoE-/- augmented pro-atherogenic/inflammatory and antigen-presenting cells (APC) feature in both subsets due to elevated expression of cytokine genes (Cxcl11, Cntf, Il24, Xcl, Ccr5, Mpl, and Acvr2a) and MHCII gene (H2-Aa and H2-Ea-ps). Finally, we modeled immunological gene expression changes and functional implications in MC differentiation and adaptive immune response for MC subsets from control and ApoE-/- mice.ConclusionsLy6Chigh MC presented pro-inflammatory/atherogenic features and lower APC potential. Ly6Clow MC displayed anti-inflammatory/atherogenic features and higher APC potential. ApoE-/- confers upon both subsets with augmented pro-atherogenic/inflammatory function and APC potential.

Comprehensive Analysis of the Potential Immune-Related Biomarker Transporter Associated With Antigen Processing 1 That Inhibits Metastasis and Invasion of Ovarian Cancer Cells

Transporter associated with antigen processing 1 (TAP1) is a protein related immune regulation and plays a role in several malignant tumors. However, the effect of TAP1 on immune infiltration, immunotherapy, and metastasis in different cancers has not been reported till date. The cancer genome atlas database, the tumor immune estimation resource database, and the estimation of stromal and immune cells in malignant tumors using expression (ESTIMATE) algorithm were used to determine the correlation between TAP1 expression and the prognosis of a variety of cancers, immune infiltration, immune checkpoint genes, DNA methylation, and neoantigens. Various enrichment analyses were used to study the correlation between TAP1 and key transcription factors using the Kyoto encyclopedia of genes and genomes (KEGG) pathway in ovarian cancer. Immunological methods were used to evaluate the expression of TAP1 protein in ovarian and cervical cancer, and Kaplan–Meier analysis was used to analyze the prognostic value of TAP1. RNA interference (RNAi) was used to verify the effect of TAP1 on ovarian cancer. Compared with normal tissues, cancer tissues showed a significant increase in the expression of TAP1, and TAP1 expression was related to the poor prognosis of cancers such as ovarian cancer. The expression level of TAP1 was correlated with immune checkpoint genes, DNA methylation, tumor mutation burden, microsatellite instability, and neoantigens in various cancers. Our results showed that TAP1 was upregulated in ovarian cancer cell lines and was associated with poor prognosis. Further, we verified the expression of TAP1-related transcription factors (MEF2A and LEF1) and found that TAP1 was closely related to ovarian cancer metastasis in vitro and in vivo. These results indicated that TAP1 could be used as a biomarker for the diagnosis and prognosis of cancer and as a new therapeutic target.

Identification and Validation of N6-methyladenosine-related Biomarkers for Bladder Cancer: Implications for Immunotherapy

N6-methyladenosine (m6A) has emerged as one of the most important modifications of RNA. Based on the expression of 23 kinds of m6A regulatory factors, we identified three different m6A modification patterns in bladder cancer. The effects of the three kinds of m6A modification modes on clinicopathological characteristics, immune cell infiltration level, and gene expression level of immune checkpoint genes were comprehensively analyzed. In addition, the effects of different m6A modification modes on the therapeutic efficacy of anti-PD-L1 (atezolizumab) are also discussed. Our results confirm that m6A methylation plays an important role in the immune cell recruitment process in the tumor microenvironment of bladder cancer, which is influences the efficacy of anti-PD-L1 therapy for bladder cancer. We further confirmed the important role of FTO on the biological function of bladder cancer cells by in vitro experiments, FTO functions as an oncogene in bladder cancer cells, and after FTO knockdown, the level of m6A enzyme activity in bladder cancer cells was significantly increased, apoptosis was increased, and cell proliferation and cell invasion were reduced. In addition, our study also confirmed that K216H and K216E probably are important targets for regulating FTO in the future. We provide new insights into the regulatory pathways of the immune microenvironment and the methylation function of m6A in bladder cancer, which will help to design novel diagnostic methods, prognostic tools, and therapeutic targets.

Identification of the ferroptosis-related long non-coding RNAs signature to improve the prognosis prediction and immunotherapy response in patients with NSCLC

Background Non-small cell lung cancer (NSCLC) is the most prevalent type of lung carcinoma with an unfavorable prognosis. Ferroptosis is involved in the development of multiple cancers. Whereas, the prognostic value of ferroptosis-related lncRNAs in NSCLC remains uncertain. Methods Gene expression profiles and clinical information of NSCLC were retrieved from the TCGA database. Ferroptosis-related genes (FRGs) were explored in the FerrDb database and previous studies, ferroptosis-related lncRNAs (FRGs-lncRNAs) were identified by the correlation analysis and the LncTarD database. The differentially expressed FRGs-lncRNAs were screened and FRGs-lncRNAs associated with the prognosis were explored by univariate Cox regression analysis and Kaplan–Meier survival analysis. Then, an FRGs-lncRNAs signature was constructed and verified by the Lasso-penalized Cox analysis. Finally, the potential correlation between risk score, immune checkpoint genes, and chemotherapeutic sensitivity was further investigated. Results 129 lncRNAs with a potential regulatory relationship with 59 differentially expressed FRGs were found in NSCLC, of which 10 were related to the prognosis of NSCLC (P < 0.05). 9 prognostic-related FRGs-lncRNAs were used to construct the prognostic model and stratify NSCLC patients into high- and low-risk groups. A worse outcome was found in patients with high risk (P < 0.05). Moreover, a good predictive capacity of this signature in predicting NSCLC prognosis was confirmed. Additionally, 45 immune checkpoint genes and 4 chemotherapeutics drugs for NSCLC were identified to be correlated with the risk score. Conclusion A novel FRGs-lncRNAs signature was successfully constructed, which may contribute to improving the management strategies of NSCLC.

Correlations between P2RX1 Expression and Gastrointestinal Cancers Prognosis and Immune Infiltration Based on Bioinformatics Analysis

This study was conducted to explore the correlations between the expression, methylation, and various clinicopathological factors of purinergic P2X1 receptor (P2RX1) and the prognosis of patients with gastrointestinal tumors. The Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) databases were used to analyze the expression of P2RX1 in different types of gastrointestinal cancers. Kaplan-Meier analysis and univariate Cox regression analysis were used to analyze the correlations between P2RX1 expression and the prognosis of various gastrointestinal tumors. Correlations between P2RX1 expression and N6 methyladenine (m6A)-related genes as well as immune checkpoint genes were analyzed by R packages (R version: 4.0.3) based on TCGA database. The association between P2RX1 methylation level and the prognosis of patients with gastrointestinal cancers was analyzed using the MethSurv database. In order to explore the biological functions of P2RX1 in hepatocellular carcinoma, the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analysis were carried out using R software. In order to evaluate the correlations between P2RX1 and tumor immune infiltration, Spearman correlation test was performed. The correlations between P2RX1 expression and immune score as well as immune checkpoint genes were analyzed based on TCGA and Tumor Immune Estimation Resource (TIMER) databases. The expression of P2RX1 was found to be significantly downregulated in gastrointestinal tumors except in cholangiocarcinoma (P < 0.05). High expression of P2RX1 tended to present better prognosis in hepatocellular carcinoma (P < 0.05). It was noted that cg06475633 of P2RX1 presented a higher methylation level compared with other CpG sites in hepatocellular carcinoma. Overall, six CpGs of P2RX1 were associated with significant prognosis in patients with hepatocellular carcinoma (P < 0.05). Among all the 20 m6A-related genes, Wilms’ tumor 1-associating protein (WTAP) was the most strongly correlated with P2RX1 in hepatocellular carcinoma. Gene enrichment analysis showed that P2RX1 is widely involved in the proliferation, activation, organization, and differentiation of various immune cells. After investigating the TIMER database, P2RX1 was found to be tightly correlated with immune infiltrating cells in gastrointestinal tumors, especially with dendritic cells. Moreover, P2RX1 was found to be strongly positively associated with programmed cell death 1 (PD1), programmed death-ligand 1 (PD-L1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA4) in hepatocellular carcinoma (P < 0.05). In conclusion, the dual role of P2RX1 in cancers and its involvement in the recruitment as well as regulation of tumor infiltrating cells in gastrointestinal cancers may be appreciated through this study.

A pan-cancer analysis of the glutaminase and their association with prognosis, tumor microenvironment, and therapeutic targets

BackgroundGlutamine metabolism plays a key role in various biological processes of tumor. Glutaminase (GLS) is involved in Glutamine metabolism and plays a conserved regulatory role in the process. Nevertheless, there is no comprehensively analysis of GLS in pan-cancer.MaterialsComprehensive bioinformatics analysis was adopted to investigate the expression level, prognostic values, and association between expression of GLS and TME, immune cells' infiltration, immune checkpoint genes, TMB, MSI, drug sensitivity in pan-cancer. Bioinformatics tools including CCLE, immunophenoscore (IPS), Tumor Immune Dysfunction and Exclusion (TIDE), GSEA, and TIMER databases were used.ResultsDifferently expressed GLS between tumor and normal tissues were analyzed, and the clinical prognoses, MMR, MSI, and TMB in multiple types of cancer were associated with GLS expression. Furthermore, GLS closely correlated with tumor immunity and drug sensitivity, and found GLS were predicted to be involved in cancer metabolism and immunity pathways, through gene set enrichment analysis (GSEA).ConclusionThe GLS expression could be used as a prognostic biomarker for determining prognosis and provide further insights into anti-glutamine metabolism for cancer.

ACSL4 Expression Is Associated With CD8+ T Cell Infiltration and Immune Response in Bladder Cancer

ObjectiveThis study aimed to explore the role of ACSL4 in CD8+ T cell tumor infiltration and outcomes of bladder cancer (BLCA) patients after immunotherapy.MethodsThe correlation between ACSL4 expression and tumor infiltration of immune cells was analyzed using the Tumor Immune Estimation Resource database. The prognostic significance of ACSL4 in BLCA was analyzed using Kaplan–Meier curves. Immunohistochemistry was used to detect CD8+ T cell infiltration in tumors with high and low ACSL4 expression obtained from patients at the Fudan University Shanghai Cancer Center. The relationships between immune checkpoint genes and immune response were analyzed using The Cancer Genome Atlas and IMvigor 210 cohorts. The molecular functions, cellular components, and biological processes involving ACSL4 were explored using Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment pathway analyses.ResultsThe expression level of ACSL4 was significantly correlated with the infiltration of CD8+ T cells in BLCA tumors (r = 0.192, P = 2.22e-04). Elevated ACSL4 was associated with suppressed tumor progression and better outcomes for BLCA patients. The higher expression level of ACSL4 predicted better immunotherapeutic responses and was associated with higher expression levels of core immune checkpoint genes, including CD274, CTLA4, PDCD1, and LAG3, compared with the low ACSL4 expression group.ConclusionThis study demonstrated for the first time that elevated ACSL4 correlated significantly with CD8+ T cell infiltration and contributed to better immunotherapeutic responses in BLCA patients. Furthermore, ACSL4 serves as a novel biomarker for predicting patient outcomes after immunotherapeutic treatments, which may improve the development of individualized immunotherapy for BLCA.