Background CST1 , acting as an oncogene, plays a critical role in tumor microenvironment (TME) remodeling. However, the function of CST1 in gastric cancer (GC) remains elusive. The purpose of this study was to explore the prognostic significance, tumor immune cell infiltration and biological functions of CST1 as a novel therapeutic candidate biomarker for GC.
Methods Differentially expressed genes (DEGs) were identified using the library (“limma”) package of R software. Gene Set Enrichment Analysis (GSEA) was applied to explore the molecular function of CST1 . CST1 expression in GC cell lines was detected using quantitative real-time PCR (RT-qPCR) in vitro. Cell proliferation, migration, and invasion were measured using the cell counting kit-8 assay and Transwell assay.
Results A total of 142 common DEGs were screened out in four datasets. Four overlapped DEGs ( CST1 , CLDN4 , CLDN7 and CLDN1 ) were identified and validated in TCGA database. CST1 was the most significant to be selected for further study. Bioinformatics analysis revealed that CST1 expression was associated with in tumor immune cell infiltration and clinical factors in GC. The survival analysis showed that CST1 overexpression predicted poor outcome in GC patients. In Cancer Cell Line Encyclopedia (CCLE) database, the expression of SULT1C4 , PAGE4 and FPR3 was significant positively related to CST1 . CST1 was also upregulated in GC cells AGS by qRT-PCR. Finally, we found that CST1 promoted cell proliferation, invasion, and migration in GC.
Conclusion This study reveals that CST1 is a promising candidate biomarker for prognosis and potential therapy target for GC.