Expression and Regulatory Roles of Small Nucleolar RNA Host Gene 4 in Gastric Cancer.

Aims: The role of SNHG4 in the initiation and development of gastric cancer.

Background: Gastric cancer is one of the leading causes of cancer death worldwide. Studies have shown that lncRNAs have a regulatory function in human diseases, particularly cancers. Small nuclear RNA host gene 4 (SNHG4) has been known as an oncogenic long noncoding RNA (lncRNA) in various cancers, and its dysregulation can lead to tumorigenesis and cancer progression.

Objective: Alteration of SNHG4 expression in gastric cancer and its correlation with clinical features of patients with stomach cancer; also, the accomplishment of bioinformatic analysis to find the potential pathways which could be impressed by changes in SNHG4 RNA expression.

Methods: The present study aims to determine the molecular mechanism of SNHG4 and the effects of its expression on the development of GC. Based on the bioinformatics investigations, we studied gene expression analysis, Kaplan-Meier survival, Gene ontology (GO), KEGG pathway enrichment, microRNA targets, transcription factor targets, and proteins interacting with SNHG4. During the experimental phase, SNHG4 expression was examined by quantitative real-time PCR (qRTPCR) in 40 paired gastric adenocarcinoma tissues and normal neighboring tissues. Also, we investigated the correlation between SNHG4 expression and patients' clinicopathological characteristics.

Results: Increased SNHG4 expression was detected in GC tissues, which is significantly associated with the TNM stage, grade group, tumor size, and metastatic status. Evaluation survival analysis demonstrated that overexpression of SNHG4 in GC tissues is remarkably related to poor overall survival (OS). SNHG4 is closely related to miR-490 and E2F family transcription factors. GO analysis suggested the possible role of SNHG4 in cell-cell adhesion, and KEGG enrichment analysis revealed that SNHG4 could be associated with the gastric cancer signaling pathway. ELAVL1 and IGF2BP2 have the highest number of SNHG4 target sites, and these proteins are involved in the PI3K-Akt-mTOR and ERK-MAPK signaling pathways.

Conclusion: Based on our results, we conclude that SNHG4 may have a function in GC development by regulating tumor-related signaling pathways.