MicroRNAs (miRs) have been implicated in the development and progression of osteosarcoma (OS). However, the underlying mechanism of miR-101 in regulating of the proliferation, migration and invasion of OS cells remains to be elucidated. In the present study, reverse transcription-quantitative polymerase chain reaction data revealed that miR-101 was frequently downregulated in the tissue samples of 12 patients with OS compared with their matched adjacent non-tumor tissues. Furthermore, miR-101 was significantly downregulated in three common OS cell lines, Saos-2, MG63 and U2OS, compared with the human osteoblast cell line, hFOB1.19 (P<0.01). A luciferase reporter assay was also performed and identified c-FOS as a novel target of miR-101 in U2OS cells; overexpression of miR-101 significantly suppressed the protein expression levels of c-FOS, while knockdown of miR-101 significantly enhanced the formers' expression levels in U2OS cells (P<0.01). Independent inhibition of c-FOS and overexpression of miR-101 expression levels significantly suppressed U2OS cell proliferation, migration and invasion (P<0.01). However, overexpression of c-FOS reversed the inhibitory effect of miR-101 upregulation on proliferation, migration and invasion of U2OS cells, suggesting that miR-101 acts as a tumor suppressor in OS cells via targeting of c-FOS. Thus, we propose that the miR-101/c-FOS axis may be a potential therapeutic target for OS.

This study was designed to evaluate the effects of drilling through the growth plate and using adipose-derived stem cells (ADSCs) and bone morphogenetic protein-2 (BMP-2) to treat femoral head epiphyseal ischemic necrosis, which can be done in juvenile rabbits. Passagefour bromodeoxyuridine (BrdU)-labeled ADSCs were cultured, assayed with MTT to determine their viability and stained with alizarin red dye to determine their osteogenic ability. Two-month-old, healthy male rabbits (1.2 to 1.4 kg, n=45) underwent ischemic induction and were randomly divided into five groups (group A: animal model control; group B: drilling; group C: drilling & ADSCs; group D: drilling & BMP-2; and group E: drilling & ADSCs & BMP-2). Magnetic resonance imaging (MRI), X-ray imaging, hematoxylin and eosin staining and BrdU immunofluorescence detection were applied 4, 6 and 10 weeks after treatment. Approximately 90% of the ADSCs were labeled with BrdU and showed good viability and osteogenic ability. Similar results were observed in the rabbits in groups C and E at weeks 6 and 10. The animals of groups C and E demonstrated normal hip structure and improved femoral epiphyseal quotients and trabecular areas compared with those of the groups A and B (P<0.01). Group D demonstrated improved femoral epiphyseal quotients and trabecular areas compared with those of groups A and B (P<0.05). In summary, drilling through the growth plate combined with ADSC and BMP-2 treatments induced new bone formation and protected the femoral head epiphysis from collapsing in a juvenile rabbit model of femoral head epiphyseal ischemic necrosis.

This study aimed to examine the biocompatibility of calcium titanate (CaTiO) coating prepared by a simplified technique in an attempt to assess the potential of CaTiO coating as an alternative to current implant coating materials. CaTiO-coated titanium screws were implanted with hydroxyapatite (HA)-coated or uncoated titanium screws into medial and lateral femoral condyles of 48 New Zealand white rabbits. Imaging, histomorphometric and biomechanical analyses were employed to evaluate the osseointegration and biocompatibility 12 weeks after the implantation. Histology and scanning electron microscopy revealed that bone tissues surrounding the screws coated with CaTiO were fully regenerated and they were also well integrated with the screws. An interfacial fibrous membrane layer, which was found in the HA coating group, was not noticeable between the bone tissues and CaTiO-coated screws. X-ray imaging analysis showed in the CaTiO coating group, there was a dense and tight binding between implants and the bone tissues; no radiation translucent zone was found surrounding the implants as well as no detachment of the coating and femoral condyle fracture. In contrast, uncoated screws exhibited a fibrous membrane layer, as evidenced by the detection of a radiation translucent zone between the implants and the bone tissues. Additionally, biomechanical testing revealed that the binding strength of CaTiO coating with bone tissues was significantly higher than that of uncoated titanium screws, and was comparable to that of HA coating. The study demonstrated that CaTiO coating in situ to titanium screws possesses great biocompatibility and osseointegration comparable to HA coating.

Chemoresistance is a major cause for the poor prognosis of osteosarcoma (OS) patients. However, our understanding of mechanisms underlying chemoresistance in OS are limited. The present study aimed to investigate the effect of stathmin 1 (STMN1) on paclitaxel-induced chemoresistance, as well as the underlying mechanism. Western blot analysis data revealed that the expression level of STMN1 was dramatically increased in OS cell lines (HOS, Saos-2, U-2OS and MG-63), when compared to normal osteoblast hFOB1.19 cells. Furthermore, treatment with paclitaxel led to upregulation of STMN1 in U-2OS cells, accompanied by activation of autophagy, which may attenuate the cytotoxicity of paclitaxel in OS cells. Following knockdown of STMN1 expression, paclitaxel-induced autophagy was significantly reduced, accompanied by increased cytotoxicity of paclitaxel to U-2OS cells. In addition, blockade of mammalian target of rapamycin signaling attenuated the inhibitory effect of STMN1 knockdown on autophagy in OS cells. In conclusion, the present study demonstrated that knockdown of STMN1 enhances osteosarcoma cell chemosensitivity to paclitaxel through inhibition of autophagy. Therefore, STMN1 may be a potential target for the treatment of chemoresistant OS.