MicroRNA-206 Reduces Osteosarcoma Cell Malignancy In Vitro by Targeting the PAX3-MET Axis.

This study was undertaken to explore how miR-206 represses osteosarcoma (OS) development. Expression levels of miR-206, PAX3, and MET mRNA were explored in paired OS and adjacent tissue specimens. A patient-derived OS cell line was established. miR-206 overexpression and knockdown were achieved by lentiviral transduction. PAX3 and MET overexpression were achieved by plasmid transfection. Treatment with hepatocyte growth factor (HGF) was utilized to activate c-Met receptor. Associations between miR-206 and PAX3 or MET mRNA in OS cells were verified by AGO2-RNA immunoprecipitation assay and miRNA pulldown assay. OS cell malignancy was evaluated in vitro by cell proliferation, metastasis, and apoptosis assays. PAX3 and MET gene expression in OS cells was assayed by RT-qPCR and Western blot. Activation of PI3K-AKT and MAPK-ERK in OS cells were assayed by evaluating Akt1 Ser473 phosphorylation and total threonine phosphorylation of Erk1/2, respectively. Expression levels of miR-206 were significantly decreased in OS tissue specimens, compared to adjacent counterparts, and were inversely correlated with expression of PAX3 and MET mRNA. miR-206 directly interacted with PAX3 and MET mRNA in OS cells. miR-206 overexpression significantly reduced PAX3 and MET gene expression in OS cells in vitro, resulting in significant decreases in Akt1 and Erk1/2 activation, cell proliferation, and metastasis, as well as increases in cell apoptosis, while miR-206 knockdown showed the opposite effects. The effects of miR-206 overexpression on OS cells were reversed by PAX3 or MET overexpression, but only partially attenuated by HGF treatment. miR-206 reduces OS cell malignancy in vitro by targeting PAX3 and MET gene expression.

Zhan FB ，Zhang XW ，Feng SL ，Cheng J ，Zhang Y ，Li B ，Xie LZ ，Deng QR ... -  《-》

Loss of MicroRNA-489-3p promotes osteosarcoma metastasis by activating PAX3-MET pathway.

Osteosarcoma (OS) remains one deadly disease for many affected patients. MicroRNAs (miRNAs) are thought to have an important role in tumor metastasis by regulating diverse cellular pathways. Here, we describe the function and regulation network of miR-489-3p in osteosarcoma (OS) metastasis. MiR-489-3p expression was downregulated in OS cells especially in high metastatic potential cells and was also significantly decreased in metastatic lesions compared with their corresponding primary tumor samples. Both gain- and loss-of-function studies confirmed that miR-489-3p significantly suppressed OS cell invasion and metastasis both in vitro and in vivo. Mechanistically, paired box gene 3 (PAX3) was identified as a functional target of miR-489-3p in OS cells. MiR-489-3p inhibited OS metastasis by negatively regulating expression of PAX3. In addition, PAX3 expression was markedly higher in OS tissues than in adjacent non-cancerous tissues. Transwell assays and in vivo metastasis assays demonstrated that overexpression of PAX3 significantly promoted the invasiveness and pulmonary metastasis of OS cells. On the other hand, downregulation of PAX3 markedly reduced cell metastatic potential. Mechanistic investigations indicated that prometastasis function of PAX3 was mediated by upregulating downstream target MET tyrosine kinase receptor. In conclusion, our results reveal that miR-489-3p-PAX3-MET signaling is critical to OS metastasis. Targeting the pathway described here may open new therapeutic prospects to restrict the metastatic potential of OS. © 2016 Wiley Periodicals, Inc.

Liu Q ，Yang G ，Qian Y 《-》

LncRNA TUG1 promotes cell proliferation and suppresses apoptosis in osteosarcoma by regulating miR-212-3p/FOXA1 axis.

LncRNA taurine upregulated gene 1 (TUG1) was reported to act as a possible oncogene in osteosarcoma (OS) development. However, the underlying molecular basis of TUG1 involved in the progression of OS remains to be thoroughly investigated. The expressions of TUG1 and miR-212-3p in OS tissues and cells were examined by RT-qPCR. Cell proliferation, apoptosis, caspase-3 activity, protein levels of BCL2, Bax, and forkhead box A1 (FOXA1) were detected by colony formation assay, MTT assay, flow cytometry analysis, caspase-3 activity assay, and western blot. Luciferase reporter assay, RNA immunoprecipitation (RIP) assay, and RT-qPCR were used to explore the interaction between TUG1, FOXA1 and miR-212-3p. Tumor xenograft mouse model was used to confirm the biological role of TUG in OS in vivo. Elevated TUG1 and FOXA1 expression and reduced miR-212-3p expression were observed in OS tissues and cells. TUG1 knockdown suppressed OS cell proliferation and promoted apoptosis. TUG1 functioned as a ceRNA of miR-212-3p and suppressed miR-212-3p expression. miR-212-3p inhibition reversed the effect of TUG1 knockdown on OS cell proliferation and apoptosis. In addition, FOXA1 was identified as a target of miR-212-3p and TUG1 functioned as a ceRNA to upregulate FOXA1 by sponging miR-212-3p in OS cells. FOXA1 up-regulation abolished the effects of miR-212-3p on OS cell proliferation and apoptosis. TUG1 promoted OS cell proliferation and suppressed apoptosis by regulating the miR-212-3p/FOXA1 axis. Therefore, TUG1/miR-212-3p/FOXA1 axis may be a promising therapeutic target in OS treatment.

Xie C ，Chen B ，Wu B ，Guo J ，Cao Y ... -  《-》

MicroRNA-876-5p inhibits cell proliferation, migration and invasion by targeting c-Met in osteosarcoma.

Recently, aberrant expression of miR-876-5p has been reported to participate in the progression of several human cancers. However, the expression and function of miR-876-5p in osteosarcoma (OS) are still unknown. Here, we found that the expression of miR-876-5p was significantly down-regulated in OS tissues compared to para-cancerous tissues. Clinical association analysis indicated that underexpression of miR-876-5p was positively correlated with advanced clinical stage and poor differentiation. More importantly, OS patients with low miR-876-5p level had a significant shorter overall survival compared to miR-876-5p high-expressing patients. In addition, gain- and loss-of-function experiments demonstrated that miR-876-5p restoration suppressed whereas miR-876-5p knockdown promoted cell proliferation, migration and invasion in both U2OS and MG63 cells. In vivo studies revealed that miR-876-5p overexpression inhibited tumour growth of OS in mice. Mechanistically, miR-876-5p reduced c-Met abundance in OS cells and inversely correlated c-Met expression in OS tissues. Herein, c-Met was recognized as a direct target of miR-876-5p using luciferase reporter assay. Notably, c-Met restoration rescued miR-876-5p attenuated the proliferation, migration and invasion of OS cells. In conclusion, these findings indicate that miR-876-5p may be used as a potential therapeutic target and promising biomarker for the diagnosis and prognosis of OS.

Xie W ，Xiao J ，Wang T ，Zhang D ，Li Z ... -  《-》

MiR-1 Suppresses Proliferation of Osteosarcoma Cells by Up-regulating p21 via PAX3.

miRNA-1(miR-1) is down-regulated in various cancer cells including osteosarcoma cells. This study was conducted to analyze the function of miR-1 in osteosarcoma cells. miR-1 expression in osteosarcoma cells was evaluated by qRT-PCR. Cell proliferation was evaluated after transfecting miR-1 by WST8 assay and FACS analysis, both in vitro and in vivo. Overexpression of miR-1 suppressed cell proliferation and induced cell-cycle arrest in the G0-G1 phase by increasing p21 levels via a p53-independent pathway. Overexpression of miR-1 down-regulated PAX3, a potential p21-regulating gene. Moreover, knockdown of PAX3 suppressed cell proliferation by increasing p21 levels, and induced arrest at the G0/G1 phase. Administration of miR-1 showed an in vivo antitumor effect. Overexpression of miR-1 suppressed cell proliferation and induced arrest in the G0/G1 phase by increasing p21 levels via a p53-independent pathway through PAX3 suppression. These results indicate that miR-1 could be a therapeutic target for osteosarcoma.

Fujii R ，Osaka E ，Sato K ，Tokuhashi Y ... -  《-》