Abstract
BACKGROUND: ITGA5 is an oncogene that performs its biological function by integrating the intracellular structure and extracellular matrix. Our research group found that ITGA5 is a gastric cancer-related gene highly expressed in this tumor and is closely related to its proliferation and metastasis. The ITGA5 gene is regulated by multiple miRNAs during the occurrence and development of tumors. This study aimed to explore the role of targeting miRNAs upstream of ITGA5 in the regulation of the proliferation, invasion, and migration of gastric cancer cells.
METHODS: The target miRNA molecules regulating the ITGA5 gene were predicted by four bioinformatics databases (TargetScan、miRDB、miRTarBase and mirDIP), and the unreported miRNAs with high correlation were selected and their expression in gastric cancer was assessed by qRT-PCR and western blot. The miRNAs with potential targeting abilities were further verified by dual luciferase reporter gene experiment. The effects of miR-330-5p and ITGA5 on the proliferation, invasion, and migration of gastric cancer cells were evaluated by CCK8, clonogenic assay, and Transwell chamber assay, respectively.
RESULTS: Six miRNAs (miR-26a-5p、miR-92a-3p、miR-148a-3p、miR-148b-3p、miR-330-5p and miR-152-3p) with high stability and conservation were found, and miR-330-5p was the one targeting and regulating ITGA5. In vitro experiments demonstrated that miR-330-5p mimic significantly inhibited the proliferation, invasion, and migration of gastric cancer cells compared with the control group (p < 0.05). The transfection of miR-330-5p mimic into gastric cancer cells overexpressing ITGA5 (OE-ITGA5) resulted in a significant reversion of the promoting effect of OE-ITGA5 on the proliferation, invasion, and migration of gastric cancer cells (P < 0.05). In addition, miR-330-5p mimic reduced ITGA5 expression in gastric cancer cells and partially reversed the FAK/AKT signaling pathway activated by the ITGA5 gene. miR-330-5p inhibitor increased ITGA5 expression in gastric cancer cells, and they partially reversed the FAK/AKT signaling pathway blocked by sh-ITGA5.
CONCLUSIONS: ITGA5 was promotive for GC tumor growth and cell biological behaviors, and miR-330-5p targeted 3'-UTR of ITGA5 and inhibited its expression. ITGA5 was expected to become a new molecular marker, with miR-330-5p representing a novel therapeutic target for GC. This discovery provides a theoretical basis to further understand the mechanism related to the occurrence and development of gastric cancer, improving the diagnosis and prognosis while discovering a new therapeutic target.