LAUSR

OBJECTIVE To uncover the role of microRNA-339-5p (miRNA-339-5p) in the development of gastric cancer (GC) and its possible molecular mechanism. METHODS Differential expressions of miRNA-339-5p in GC and adjacent normal tissues were detected. The relationship between miRNA-339-5p level and clinical features in GC patients was analyzed. Proliferative and migratory changes in BGC-823 and SGC-7901 cells overexpressing miRNA-339-5p were examined. Finally, luciferase assay and rescue experiments were conducted to explore the regulatory mechanism of miRNA-339-5p in its downstream gene ALKBH1, and their interaction in the development of GC. RESULTS MiRNA-339-5p was downregulated in GC tissues. Lowly expressed miRNA-339-5p was unfavorable to prognosis in GC because of high rates of lymphatic metastasis and distant metastasis. Overexpression of miRNA-339-5p markedly reduced proliferative and migratory abilities in GC cells. ALKBH1 was identified to be the downstream gene of miRNA-339-5p. In GC tissues, ALKBH1 was upregulated and negatively correlated to miRNA-339-5p level. Overexpression of ALKBH1 was able to reverse the inhibitory effects of overexpressed miRNA-339-5p on proliferative and migratory abilities in GC. CONCLUSIONS Lowly expressed miRNA-339-5p is closely related to metastasis and poor prognosis in GC patients. MiRNA-339-5p suppresses the malignant development of GC by negatively regulating ALKBH1.