MicroRNA-597 Suppresses Gastric Cancer Invasion and Progression via RUNX1 Targeting, an Effect Attenuated by the Long Non-Coding RNA KCNQ1OT1.

Aberrant expression of multiple microRNAs has been reported in gastric cancer. In particular, microRNA-597 has been associated with poor survival rates but is not yet well characterized. Seventy-five clinical samples, four cell lines, and two patient-derived organoids were evaluated for the expression of microRNA-597 and its target genes. microRNA-597 was transiently transfected for analysis of cell migration, invasion, wound healing, colony formation, and cell viability, and its regulation by long non-coding RNAs was explored using the TCGA-STAD and LncBook tools. In clinical samples, low expression of microRNA-597 was associated with the intestinal subtype (p = 0.002) and stages III and IV (p = 0.048). All functional readouts were reduced after microRNA-597 transfection, including colony formation, in patient-derived organoids. Among target genes, RUNX1 was directly regulated by microRNA-597. Other cell invasion genes were dependent on RUNX1 as a hub for regulation. Analysis of the Intersection between long non-coding RNAs co-expressed with RUNX1 and those with the highest microRNA-597 prediction binding identified KCNQ1OT1 as the top transcript. Silencing of KCNQ1OT1 and co-expression in clinical samples suggest the existence of a KCNQ1OT1/microRNA-597/RUNX1 network. The results indicate that microRNA-597 directly suppresses RUNX1, while KCNQ1OT1 modulates this interaction. Our approach enabled the simultaneous analysis of dysregulation in three families of transcripts in gastric cancer progression.