The Influence of miR-3149 on the Malignancy Progression of Gastric Cancer by Negatively Regulating CEACAM5

Abstract

Background: There are some reports indicating that carcinoembryonic antigen associated cell adhesion molecule 5 (CEACAM5) can act as a diagnostic indicator or molecular marker for GC, but its upstream regulatory pathway still needs to be explored. microRNAs (miRNAs) regulate gene expression at the translation level and fulfil a crucial role in GC physiologyin, whether miR-3149 in family members can affect GC progression by regulating CEACAM5 is still unclear. Methods: miR-3149 and CEACAM5 expressions in GC tissues and cells (N87, AGS, and HGC-27) were observed by RT-qPCR or Western blot. Intervened the miR-3149 and CEACAM5 expression in GC cells, CCK8, Wound healing, Transwell and flow cytometry assays evaluated cell activity and function separately, while detecting related proteins. Predicted the target of miR-3149 and the expression of CEACAM5 in tumor tissue through bioinformatics analysis and evaluated the correlation between both using Spearman analysis. Verified the targeting relationship between the two through the Luciferase reporter assay. Conducted another rescue experiment on CEACAM5 overexpression to further verify this relationship. Results: In GC tissues and cells, miR-3149 and CEACAM5 expression levels were respectively down-regulated and up-regulated. Transfection of miR-3149 mimics or inhibitors respectively reduced or increased GC cell apoptosis and inhibited or encouraged cell proliferation, migration and invasion, which were shown to be enhanced or inhibited respectively by transfection of OE-CEACAM5/Si-CEACAM5, while their apoptosis rate decreased or increased. miR-3149 could target regulating CEACAM5, and showed an inverse correlation with the expression of CEACAM5. The impacts of miR-3149 mimics on the malignancy progression of GC could be partially reversed by OE-CEACAM5. Conclusion: The results indicate that miR-3149 can downregulate the expression of CEACAM5 to inhibit the malignancy progression, as a GC suppressor,which identify a new miRNA mediated tumor suppressor mechanism in GC.