MicroRNA-18 b promotes cell proliferation and inhibits apoptosis of gastric cancer via targeting KIAA 1324

Gastric cancer (GC) is the fourth most predominant malignancy worldwide and remains the second most common cause of cancer-related death globally. Recent studies have shown that miRNAs are involved in the tumorigenesis of GC. MicroRNA-18b (miR-18b) has been reported to be upregulated in primary gastric cancer tissues compared with adjacent non-tumorous tissues. However, the specific prognostic value and biological roles of miR-18b in gastric cancer still remains unknown. In this study, we firstly verified that miR-18b expression was really up-regulated in cancerous tissues and overexpressed miR-18b in tumorand adjacent-tissue samples from patients with gastric cancer (GC). In addition, our results showed that low expression of miR-18b inhibited the growth and promoted the apoptosis in GC cells. From our further study, down-regulation of miR-18b also reduced tumor growth in xenograft models of gastric cancer. Moerover, we showed, by luciferase assay, a direct interaction between miR18b and the KIAA1324 3’UTR, as overexpression of miR-18b was associated with suppression of luciferase activity. Furthermore, we demonstrated that low-expression of miR-18b caused a significant upregulation of both KIAA1324 mRNA and protein. Taken together, we concluded that miR-18b promotes cell proliferation and inhibits apoptosis of gastric cancer via targeting KIAA1324 and miR-18b may serve as a useful therapeutic agent for miRNA-based GC therapy.