Cytohesin-2 Is Upregulated in Malignant Melanoma and Contributes to Tumor Growth

Integrated analysis and validation reveal CYTH4 as a potential prognostic biomarker in acute myeloid leukemia

Acute myeloid leukemia (AML) is a clonal hematological malignancy with high mortality rates. The identification of novel markers is urgent for AML. Cytohesins are a subfamily of guanine nucleotide exchange factors activating the ADP-ribosylation factor family GTPases. While the important roles of cytohesins have been reported in various cancers, their function in AML remains unclear. The present study aimed to explore the prognostic impact of cytohesin-4 (CYTH4) and the underlying molecular functions. RNA sequencing and AML clinical data were obtained from The Cancer Genome Atlas and Gene Expression Omnibus databases to investigate gene expression and survival. Using the R software, differentially expressed genes were identified between the high- and the low-CYTH4 group. Functional enrichment analysis was conducted by Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment Analyses. The CIBERSORTx tool was used to explore the proportions of different immune cell types. The molecular function of CYTH4 was also validated in vitro by examining cell growth, cell cycle, apoptosis and colony-forming ability. CYTH4 was significantly upregulated in AML compared with other cancers and normal tissues. High CYTH4 expression was associated with high white blood count (P=0.004) and higher risk status (P<0.001). Patients with high CYTH4 expression had poor overall survival (OS; HR=2.19; 95% CI, 1.40-3.44; P=0.0006; high vs. low) and event-free survival (EFS; HR=2.32; 95% CI, 1.43-3.75; P=0.0006; high vs. low), and these patients could benefit from transplantation (HR=0.29; 95% CI, 0.18-0.47; P<0.0001; transplantation vs. chemotherapy). Multivariate analysis showed that high CYTH4 expression was independently associated with inferior OS (HR=2.49; 95% CI, 1.28-4.83; P=0.007) and EFS (HR=2.56; 95% CI, 1.48-4.42; P=0.001). Functional analysis showed that CYTH4 was involved in immunoregulation. In vitro validation showed knockdown of CYTH4 adversely affected cell growth and induced cell apoptosis, while overexpression of CYTH4 enhanced cell growth. Taken together, CYTH4 is expressed at high levels in AML and can potentially function as a prognostic biomarker.

Cytohesin-4 Upregulation in Glioma-Associated M2 Macrophages Is Correlated with Pyroptosis and Poor Prognosis

Cytohesin-4 (CYTH4) is a member of the PSCD family. Members of this family appear to mediate the regulation of protein sorting and membrane trafficking. In previous studies, CYTH4 has been linked with multiple brain diseases, but not glioma, the most common type of brain tumor. We utilized multiple glioma single-cell RNA sequencing datasets and bulk data from the TCGA and CGGA and conducted GSEA and KEGG and GO analyses. Biomarker potential was tested via ROC curve analysis. Radar plots were used to study TMB and MSI correlations. Immune cell studies were conducted using CIBERSORT. All statistical analyses were performed in R software and GraphPad Prism 9. CYTH4 was overexpressed in the glioma macrophage population in several single-cell RNA sequencing datasets and was most correlated with M2 macrophages. CYTH4 expression was higher in tumor tissues and was correlated with survival and WHO grade. ROC curves suggested CYTH4 overexpression to be a potential glioma biomarker. GSEA results indicated a relationship between CYTH4 and apoptosis, and PPI analysis supported a pyroptosis correlation. KEGG and GO analysis results linked CYTH4 with antigen processing and presentation and neutrophil activities. In summary, the study identified a CYTH4/pyroptosis/M2 macrophage axis. CYTH4 was upregulated in M2 macrophages in glioma and affected pyroptosis. CYTH4 overexpression is a potential biomarker predicting a poor prognosis.