Long Noncoding RNA MRPL39 Inhibits Gastric Cancer Proliferation and Progression by Directly Targeting miR-130

Background: Gastric cancer (GC) is one of the most prevalent malignant tumors and has a very high incidence of mortality. Recently, long noncoding RNAs (lncRNAs) have been demonstrated to play an important role in the development and progression of GC. Materials and Methods: In the present study, we investigated the biological function and molecular mechanisms of lncRNA MRPL39 in GC. Results: We found that MRPL39 was significantly downregulated in GC tissues and cell lines and that its expression level was negatively associated with carcinoma size, tumor, lymph node, metastasis (TNM) stage, and lymphatic metastasis. Patients with low MRPL39 expression levels revealed a short overall and disease-free survival period. Over-expression of MRPL39 in the GC cell lines BGC823 and SGC-7901 inhibited cell growth, proliferation, migration, and invasion. MiR-130, a putative target gene of MRPL39, displayed an inverse association with the expression of MRPL39 in GC tissues and cell lines. Moreover, a luciferase assay demonstrated a direct binding between the miR-130 and MRPL39, and the reintroduction of miR-130 abrogated the anti-tumor effect of MRPL39 on GC cells. Conclusion: Taken together, these findings indicate that MRPL39 serves as a tumor suppressor by directly targeting miR-130 in GC, which suggests that it might be a novel biomarker in the diagnosis and prognosis of GC.