ABSTRACT
Recent studies have shown that microRNA-451 (miR-451) was significantly decreased in osteosarcoma tissues and was identified as a tumor suppressor in other types of human cancers. However, its clinical significance and molecular mechanisms in osteosarcoma are still not well understood. MiR-451 levels are evaluated by quantitative reverse transcription-polymerase chain reaction (RT-PCR) in osteosarcoma cell lines and in 68 pairs of osteosarcoma and adjacent noncancerous tissues. Then, the associations of miR-451 expression with clinicopathological features of patients were determined. The effects of miR-451 in osteosarcoma cells were examined by MTT and Matrigel invasion assay. The functional target of miR-451 were determined by bioinformatics analysis and validated by luciferase reporter analyses and Western blot assay. Our results showed that the expression of miR-451 was significantly downregulated in osteosarcoma tissues compared with corresponding noncancerous tissues (P < 0.01). Particularly, statistical analysis of primary human osteosarcoma indicated that decreased expression of miR-451 was correlated with metastasis and recurrence. Moreover, the miR-451 force-expression suppressed cell proliferation and invasion in vitro. Based on bioinformatics analysis, we found that chemokine ligand 16 (CXCL16) was identified as a direct functional target of miR-451. Consistent with the effects of miR-451, silencing CXCL16 could phenocopy the effects of miR-451 on phenotypes of osteosarcoma cells. Furthermore, CXCL16 expression was upregulated in osteosarcoma tissues and inversely associated with miR-451 in human osteosarcoma tissues. Our data reveal a downregulated expression of miR-451 in osteosarcoma tissues, which is inversely associated with CXCL16 levels. These observations demonstrated that miR-451 may play an important role in tumor growth and metastasis in osteosarcoma.
Subject(s)
Bone Neoplasms/genetics , Chemokines, CXC/genetics , MicroRNAs/genetics , Osteosarcoma/genetics , Receptors, Scavenger/genetics , Adult , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Bone Neoplasms/diagnosis , Bone Neoplasms/pathology , Cell Line, Tumor , Cell Proliferation/genetics , Chemokine CXCL16 , Chemokines, CXC/metabolism , Down-Regulation , Female , Gene Expression Regulation, Neoplastic , Humans , Male , MicroRNAs/metabolism , Neoplasm Invasiveness , Neoplasm Recurrence, Local/genetics , Neoplasm Recurrence, Local/metabolism , Neoplasm Recurrence, Local/pathology , Osteosarcoma/diagnosis , Osteosarcoma/pathology , Prognosis , Receptors, Scavenger/metabolism , Up-RegulationABSTRACT
BACKGROUND AND OBJECTIVE: Recent studies suggest that miR-155 is involved in lung tumorgenesis, whereas the precise mechanism has not yet been characterized. The aim of this study is to investigate the effects of over-expression of miR-155 on the growth of human lung cancer 95D cells in vitro and its possible mechanism, and thus to provide experimental evidence for further researching on the role of miR-155 in the pathogenesis and development of lung cancer. METHODS: miR-155 mimics control and miR-155 mimics were tranfected into human lung cancer 95D cells by FuGENE®HD Transfection Reagent respectively in vitro. The relative expression level of miR-155 in 95D cells was determined using specific probe of real-time PCR after transfection. The proliferation of 95D cells was detected by MTT assay. The cell cycle was analyzed by flow cytometry. The expression of SOS1 protein was measured by Western blot. RESULTS: Compared with control groups, the expression level of miR-155 was significantly increased in miR-155 mimics transfected group (P<0.05). The proliferation of miR-155-transfected 95D cells was significantly inhibited (P<0.05). The percentage of G0/G1 phase cells was increased significantly in miR-155-transfected 95D cells, while the percentage of S phase was remarkably reduced (P<0.05). Furthermore, the expression of SOS1 in miR-155-transfected 95D cells was significantly down-regulated (P<0.05). CONCLUSIONS: miR-155 could significantly inhibit the growth of human lung cancer 95D cells in vitro, which might be closely related to miR-155 induced G0/G1 phase arrest.
