Abstract
Despite significant developments in its clinical treatment, the reported incidence and mortality of gastric cancer have exhibited marked increases. The molecular mechanisms of gastric cancer initiation and progression remain to be fully elucidated. The aim of the present study was to identify novel microRNAs (miRNAs/miRs) with a role in the peritoneal metastasis of gastric cancer by comparing the miRNA expression in the gastric cancer cell line GC9811 with that in its variant GC9811-P, a sub-cell line with a high potential for peritoneal metastasis. A miRNA microarray analysis identified 153 dysregulated miRNAs, including 74 upregulated and 79 downregulated miRNAs. Of these, four significantly upregulated miRNAs (miR-181a-5p, miR-106b-5p, miR-199a-3p and miR-148a-3p) and four downregulated miRNAs (miR-146a-5p, miR-21-5p, miR-222-3p and miR-221-3p) were selected and further confirmed by reverse transcription-quantitative polymerase chain reaction analysis. Furthermore, knockdown of miR-21-5p promoted the migration and invasion of GC9811 cells. Collectively, the results suggested that the miRNA expression profile in GC9811-P vs. GC9811 cells was altered to favor disease progression, and the dysregulated miRNAs, including miR-21-5p, may therefore provide novel biomarkers and potential therapeutic targets for gastric cancer metastasis.