This study aimed to identify miRNAs that regulate the effect of antitumor drugs in pancreatic neuroendocrine tumors (PanNETs). Results: miR-185-5p suppresses AKT1 expression in PanNET cell lines, as there is a negative correlation between AKT1 and miR-185-5p expression in PanNET tissue. Although miR-185-5p-transfected PanNET cells showed higher proliferative potential than control cells, the addition of mTOR inhibitor enhanced the inhibitory effect on cell proliferation, suggesting that miR-185-5p suppresses AKT1 expression in PanNET cell lines. These results suggest that miR-185-5p is involved in suppressing AKT1 expression and enhancing cell proliferative potential, while its antitumor effect is enhanced when an mTOR inhibitor is added.