Characterization of microRNA-29 family expression and investigation of their mechanistic roles in gastric cancer

Increasing evidence shows that abnormal microRNAs (miRNAs) expression is involved in tumorigenesis. They might be the novel biomarkers or therapeutic targets in disease treatment. miR-29 family was previously reported to act as tumor suppressors or oncogenes in diverse cancers. However, their accurate expression, function and mechanism in gastric cancer (GC) are not well known. Here, we found that the expression of miR-29 family members was significantly reduced in GC compared with adjacent controls. Among them, miR-29c had the most reduced percentage in GC and was associated with aggressive and progressive phenotypes of GC. We further demonstrated that miR-29 family acted as tumor suppressors through targeting CCND2 and matrix metalloproteinase-2 genes in GC. Moreover, the inverse relationship between miR-29 family and their targets was verified in patients and xenograft mice. Finally, reintroduction of miR-29 family significantly inhibited tumor formation of GC cells in the xenograft mice. Take together, our finding characterized the expression properties of miR-29 family, contributed to the function and molecular mechanism of miR-29 family in GC and implied that miR-29 family might be employed as novel prognostic markers and therapeutic targets of GC.