Published online Jul 15, 2023. doi: 10.4251/wjgo.v15.i7.1182
Peer-review started: December 7, 2022
First decision: January 18, 2023
Revised: March 30, 2023
Accepted: April 30, 2023
Article in press: April 30, 2023
Published online: July 15, 2023
Processing time: 217 Days and 1.5 Hours
Gastric cancer (GC) is a malignant tumor with high morbidity and mortality. Expression of COL5A2 is significantly elevated in GC. Abnormal expression of noncoding RNAs (ncRNAs) have been found in GC, including microRNA (miRNA) and long noncoding RNA (lncRNA). Competing endogenous RNA network plays an important regulatory role in GC. However, its specific regulatory mechanism has not been elucidated.
To gain insight into the ncRNA regulatory mechanism and immune microenvironment related to COL5A2 in GC.
RNA sequencing data and clinical information from The Cancer Genome Atlas data portal were used to analyze the expressions of COL5A2, miRNA and lncRNA related to the prognosis of GC. Cox regression analysis and Kyoto Encyclopedia of Genes and Genomes analysis were performed to assess the risk factors and relevant function of COL5A2. StarBase was used to predict the interaction of miRNA–lncRNA or miRNA–mRNA in GC. The relationship between COL5A2, miR-144-3p and ENTPD1-AS1 were verified by dual luciferase reporter assay. The association of COL5A2 with immune cell infiltration were analyzed using the Tumor Immune Estimation Resource database and single sample gene set enrichment analysis. The expression of COL5A2 and macrophages in paired GC tissues were detected by immunohistochemical staining.
We verified that the upregulation of COL5A2 expression was associated with the prognosis of GC and was an independent risk factor for GC. miR-144-3p was downregulated and correlated with the prognosis of GC. miR-144-3p regulated the expression of COL5A2 through direct interaction with COL5A2. ENTPD1-AS1 was elevated in GC and competitively bound to miR-144-3p, thus inhibiting the expression of miR-144-3p. ENTPD1-AS1 enhanced the expression of COL5A2 through sponging miR-144-3p. Compared to paired normal tissue, COL5A2 expression was upregulated at the protein level, especially in the middle and late stages of GC. The high expression of COL5A2 was positively linked to macrophage infiltration in GC.
COL5A2 regulated by ENTPD1-AS1–miR-144-3p was associated with poor prognosis and macrophage infiltration in GC. This could be a new biomarker and therapeutic target in GC.
Core Tip: Gastric cancer (GC) is a malignant tumor with high fatality rate. Competing endogenous RNA network and infiltration of immune cells play an important role in the development of GC. In this study, we verified that high expression of COL5A2 was closely related to poor prognosis and was an independent risk factor for GC. We predicted and validated that long noncoding RNA ENTPD1-AS1 regulated the expression of COL5A2 through sponging miR-144-3p. Additionally, we confirmed that upregulation of COL5A2 expression strongly correlated with immune infiltration of macrophages. ENTPD1-AS1-miR-144-3p-COL5A2 might be a new therapeutic target for GC.