Uncontrolled growth and an enforced epithelial-mesenchymal transition (EMT) process contribute to the poor survival rate of patients with osteosarcoma (OS). Long noncoding RNAs (lncRNAs) have been reported to be involved in the development of OS. However, the significant role of lncRNA SNHG1O on regulating proliferation and the EMT process of OS cells remains unclear. In this study, quantitative real-time PCR and fluorescence in situ hybridization (FISH) results suggested that SNHG10 levels were significantly increased in OS compared with healthy tissues. In vitro experiments (including colony formation, CCK-8, wound healing, and transwell assays) and in vivo experiments indicated that downregulation of SNHG10 significantly suppressed the proliferation and invasion of OS cells. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay confirmed that SNHG10 could regulate FZD3 levels through sponging microRNA 182-5p (miR-182-5p). In addition, the SNHG10/miR-182-5p/FZD3 axis could further promote the b-catenin transfer into nuclear accumulation to maintain the activation of the Wnt singling pathway. Together, our results established that SNHG10 has an important role in promoting OS growth and invasion. By sponging miR-182-5p, SNHG10 can increase FZD3 expression and further maintain the activation of Wnt/b-catenin singling pathway in OS cells.

MicroRNAs (miRNAs) expression aberration has been discovered in almost all human cancers, thus offering a group of potential diagnostic markers, prognostic factors and therapeutic targets in tumorigenesis. Now our data showed that miR-200c, which is downregulated in osteosarcoma tissues, drives chemosensitivity to cisplatin in osteosarcoma. We demonstrated that AKT2 is a direct target of miR-200c, Spearman’s rank correlation analysis showed that the expression levels of AKT2 and miR-200c in 35 pairs of osteosarcoma specimens were inversely correlated. Moreover, miR-200c inhibited cell proliferation and cell migration. Taken together, for the first time, our results demonstrate that miR-200c plays a significant role in osteosarcoma tumor growth and chemosensitivity by regulating AKT2, which may provide a novel therapeutic strategy for treatment of osteosarcoma.

MicroRNAs are highly conserved noncoding RNA that negatively modulate protein expression at a posttranscriptional and/or translational level. MicroRNAs play an important role in the development and progression of human cancers, including osteosarcoma. Recent studies have shown that miR-100 was downregulated in many cancers; however, the role of miR-100 in human osteosarcoma has not been totally elucidated. In this study, we demonstrate that the expression of miR-100 was significantly downregulated in human osteosarcoma tissues compared to the adjacent tissues. Enforced expression of miR-100 inhibited cell proliferation, migration, and invasion abilities of osteosarcoma cells, U-2OS, and MG-63. Additionally, miR-100 also sensitized osteosarcoma cells to cisplatin and promoted apoptosis. Furthermore, overexpression of miR-100 decreased the expression of insulin-like growth factor I receptor and inhibited PI3K/AKT and MAPK/ERK signaling. In human clinical specimens, insulin-like growth factor I receptor was inversely correlated with miR-100 in osteosarcoma tissues. Collectively, our results demonstrate that miR-100 is a tumor suppressor microRNA and indicate its potential application for the treatment of osteosarcoma in future.

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Background: Osteosarcoma (OS) is a common malignant bone cancer and is still a growing threat to young people. Circular RNAs (CircRNAs) are reported to be involved in the development of diverse human cancers. However, the role of circUBAP2 in OS progression is rarely reported. Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to detect the expression levels of circUBAP2 and miR-641 in OS tissues and cells. Cell Counting Kit-8 (CCK-8) assay was employed to check cell proliferation. The ability of cell invasion was evaluated by transwell assay. The protein levels of E-cadherin, Vimentin and Yes-associated protein 1 (YAP1) were measured by western blot. The starBase was used to predict binding sites between miR-641 and circUBAP2 or YAP1 and the dual-luciferase reporter assay was performed to verify the interaction. Results: The level of circUBAP2 was significantly upregulated in OS tissues and cells compared with normal tissues and cells, which was contrary to the expression of miR-641. Downregulation of circUBAP2 suppressed proliferation and invasion of OS cells and weakened the process of epithelial-mesenchymal transition (EMT). Moreover, miR-641 was a target of circUBAP2 and could bind to the 3′-untranslated region (3′UTR) of YAP1. In addition, overexpression of circUBAP2 or YAP1 reversed the inhibitory effects of miR-641 on proliferation and invasion of OS cells. Further research indicated that circUBAP2 regulated the expression of YAP1 by interacting with miR-641 in OS cells. Conclusion: Knockdown of circUBAP2 impeded proliferation and invasion of OS cells by downregulating the expression of YAP1 via sponging miR-641.