Mechanism of action of MiR-330-5p targeting ITGA5 in the regulation of proliferation, migration, and invasionof gastric cancer.

[BACKGROUND] ITGA5 is an oncogene that performs its biological function by integrating the intracellular structure and extracellular matrix. We found that ITGA5 is highly expressed in gastric tumors and is closely related to proliferation and metastasis. Multiple miRNAs regulate the ITGA5 gene 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] Target miRNA molecules regulating the ITGA5 gene were predicted using four bioinformatics databases (TargetScan、miRDB、miRTarBase and mirDIP). The unreported miRNAs with high correlation were selected, and their expression in gastric cancer was assessed using 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 using 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) were identified. miR-330-5p was found to target and regulate 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). Transfection of miR-330-5p mimic into gastric cancer cells overexpressing ITGA5 (OE-ITGA5) significantly prevented the ability of OE-ITGA5 to promote 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 prevented FAK/AKT signaling pathway activated by the ITGA5 gene. An miR-330-5p inhibitor increased ITGA5 expression in gastric cancer cells, and partially prevented blockage of the FAK/AKT signaling pathway by sh-ITGA5.

[CONCLUSIONS] miR-330-5p was shown to affect the proliferation, invasion, and migration of gastric cancer cells by mediating ITGA5 through a mechanism possibly associated with the regulation of the FAK/AKT signaling pathway.