ObjectivesThis study aimed to investigate the functional effects of microRNA (miR)-214-5p on osteoblastic cells, which might provide a potential role of miR-214-5p in bone fracture healing.MethodsBlood samples were obtained from patients with hand fracture or intra-articular calcaneal fracture and from healthy controls (HCs). Expression of miR-214-5p was monitored by qRT-PCR at day 7, 14 and 21 post-surgery. Mouse osteoblastic MC3T3-E1 cells were transfected with antisense oligonucleotides (ASO)-miR-214-5p, collagen type IV alpha 1 (COL4A1) vector or their controls; thereafter, cell viability, apoptotic rate, and the expression of collagen type I alpha 1 (COL1A1), type II collagen (COL-II), and type X collagen (COL-X) were determined. Luciferase reporter assay, qRT-PCR, and Western blot were performed to ascertain whether COL4A1 was a target of miR-214-5p.ResultsPlasma miR-214-5p was highly expressed in patients with bone fracture compared with HCs after fracture (p < 0.05 or p < 0.01). Inhibition of miR-214-5p increased the viability of MC3T3-E1 cells and the expressions of COL1A1 and COL-X, but decreased the apoptotic rate and COL-II expression (p < 0.05 or p < 0.01). COL4A1 was a target of miR-214-5p, and was negatively regulated by miR-214-5p (p < 0.05 or p < 0.01). Overexpression of COL4A1 showed a similar impact on cell viability, apoptotic rate, and COL1A1, COL-II, and COL-X expressions inhibiting miR-214-5p (p < 0.01).ConclusionInhibition of miR-214-5p promotes cell survival and extracellular matrix (ECM) formation of osteoblastic MC3T3-E1 cells by targeting COL4A1.Cite this article: Q. S. Li, F. Y. Meng, Y. H. Zhao, C. L. Jin, J. Tian, X. J. Yi. Inhibition of microRNA-214-5p promotes cell survival and extracellular matrix formation by targeting collagen type IV alpha 1 in osteoblastic MC3T3-E1 cells. Bone Joint Res 2017;6:464–471. DOI: 10.1302/2046-3758.68.BJR-2016-0208.R2

According to the cancer stem cell theory, the presence of a small sub-population of cancer cells, termed cancer stem cells (CSCs), have a significant implication on cancer treatment and are responsible for tumor recurrence. Previous studies have reported that alterations in the Wnt/β-catenin signaling are crucial in the maintenance of CSCs. In the present study, the characteristic features and activation of Wnt/β-catenin signaling in CSCs from osteosarcoma, an aggressive human bone tumor, were investigated. In total, ~2.1% of the cancer stem-like side population (SP) cells were identified in the osteosarcoma samples. The results of subsequent western blot and reverse transcription-quantitative polymerase chain reaction analyses revealed that the protein levels of β-catenin and cyclin D1 were markedly upregulated in the fluorescence-activated cell sorted osteosarcoma SP cells. In addition, the elevated expression levels of stem cell proteins, including CD133, nestin Oct-4, Sox-2 and Nanog were significantly higher in the SP cells, which contributed to self-renewal and enhanced the proliferation rate of the SP cells. Furthermore, the SP cells were found to be highly invasive and able to form tumors in vivo. Taken together, these data suggested that the identification of novel anticancer drugs, which suppress the Wnt/β-catenin signaling and its downstream pathway may assist in eradicating osteosarcoma stem cells.

Background Osteosarcoma (OS) is one of the most primary malignant bone tumors, mainly attracting children and young adults. The microRNAs are mentioned to play vital roles in many cancers, including OS. The purpose of this study was to explore the expression and function of miR-455-3p in OS and predict the potential effects in clinical diagnosis and prognosis. Method We conducted quantitative real-time PCR to assess the expression of miR-455-3p in OS tissues and cell lines. The Cell Counting Kit-8 assay, Transwell assay, and flow cytometry were performed to assess the ability of miR-455-3p on cell proliferation, migration, invasion, and apoptosis. Kaplan–Meier curve and Cox regression analysis were used to demonstrate the survival outcome. Results This study revealed that the expression of miR-455-3p was decreased in OS tissues and cell lines. The dysregulation of miR-455-3p was in association with tumor size, distant metastasis, and clinical stage. Patients with high miR-455-3p expression had a satisfying survival rate. Multivariate Cox analysis indicated that miR-455-3p was a promising prognostic indicator. Expression of miR-455-3p could inhibit the proliferation, migration, and invasion, and facilitate apoptosis of OS cells in vitro. Conclusion These results indicated the miR-455-3p was a potential clinical therapeutic target and prognostic biomarker by suppressing the proliferation, migration, and invasion, as well as enhancing cell apoptosis.