Low expression of microRNA-98 in gastric cancer and the inhibitory effect on gastric cell growth

Objective To explore the role of microRNA (miR)-98 in gastric tumorigenesis.Methods Total RNA from tissue samples and cell lines was obtained with the Trizol isolation reagent.The real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) was used for detecting the expression of miR-98 in 32 pairs of gastric cancer tissues and matched normal gastric tissues and gastric cancer cell lines.The cell proliferation assay was done with a cell counting kit (CCK-8).DNA content analysis was done by flow cytometry with a FACS Calibur system.Results The expression of miR-98 was significantly lower in gastric cancer tissues than in normal tissues with a median change of 0.24-fold (P ＜ 0.01).The expression of miR-98 was significantly down-regulated in BGC-823 (0.79-fold),AGS (0.74-fold),HGC-27 (0.70-fold),MKN-28 (0.64-fold),and MKN-45 cells (0.28-fold) as compared with GES-1 cells.There was a significant correlation between miR-98 expression and clinical stage (P ＜ 0.05),and lymph node metastasis (P ＜ 0.05).The over-expression of miR-98 resulted in 40.79％ decrease in the rate of cell proliferation (P ＜0.01).DNA content analysis by flow cytometry revealed miR-98 restoration induced an accumulation in the percentage of cells at the G1 phase and a reduction of cells in S phase (P ＜0.05).Conclusion This study revealed that miR-98 is low-expressed in gastric cancer and acts as an anti-oncogene in regulating gastric cell growth. Key words: Gastric cancer;  MicroRNAs ;  MicroRNA-98 ;  Cell proliferation