Functional outcomes and quality of life in patients with osteosarcoma treated with amputation versus limb-salvage surgery: a systematic review and meta-analysis.

INTRODUCTION: To perform a meta-analysis for comparing the functional outcomes and quality of life (QOL) of osteosarcoma patients receiving amputation or limb-salvage surgeries. MATERIALS AND METHODS: A search was conducted of the Medline, Cochrane, EMBASE, and Google Scholar on September 30, 2013. Studies were included in the analysis if there were patients who underwent amputation and limb-salvage surgery for osteosarcoma or Ewing's sarcoma, and for whom postoperative functional outcomes and QOL were evaluated. Outcomes were compared between participants who underwent limb-salvage operation and those who underwent amputation. The methodological quality of non-randomized comparative studies was assessed using the Newcastle-Ottawa Scale. RESULTS: A total of 121 studies were identified and 6 were included in the meta-analysis. Quality assessment indicated that all six studies were of high quality. The mean age of the participants ranged from 17 to 37 years, and among them 118 underwent amputations and 138 underwent limb-salvage procedures. The mean length of follow-up ranged from 28 to 145 months. The meta-analysis indicated that functional outcomes and QOL were similar between patients who underwent amputation and those who underwent a limb-salvage procedure. CONCLUSIONS: This meta-analysis including six high-quality studies indicates that amputation and limb-salvage surgery provide similar functional outcomes and quality of life for patients with osteosarcomas.

The role of VE-cadherin in osteosarcoma cells.

Osteosarcoma cells can generate vasculogenic-like, patterned networks to obtain nutrients and oxygen, which mimic some function of endothelial-like cells and facilitate tumor malignant progress. These cells also express vascular endothelial-cadherin (VE-cadherin), which is generally accepted as a strictly endothelial-specific transmembrane protein. However, its role is still relatively obscure in osteosarcoma cells. So we inhibit the VE-cadherin gene expression with siRNA in osteosarcoma cells (MG63), and culture those cells in three-dimensional medium, containing Type I collagen or Matrigel, to observe the role of VE-cadherin. Western blotting analysis show that sequence-specific siRNA can significantly decrease the expression of VE-cadherin in MG63 cell. After knockdown of VE-cadherin, osteosarcoma cells can't induced angiogenic sprout and form osteosarcoma-generated, endothelial-like networks. Our data indicate that VE-cadherin may be a positive and specific regulator not only in angiogenesis, but also in vasculogenic mimicry of osteosarcoma cells. And it can be considered as a new prospective option in the combining treatment of aggressive tumor with highly vascularity, including osteosarcoma.

[Morphological changes in osteosarcoma xenografts in nude mice after inhibiting angiogenesis by Ad-VEGF-siRNA].

BACKGROUND AND OBJECTIVE: Vascular endothelial growth factor (VEGF) is a critical stimulator for angiogenesis of osteosarcoma. This study was to investigate the morphological changes in osteosarcoma xenografts in nude mice after inhibiting angiogenesis by Ad-VEGF-siRNA. METHODS: The animal model of osteosarcoma xenografts was constructed by subcutaneous inoculation of osteosarcoma MG63 cells into nude mice. The mice were randomly divided into three groups, 15 mice in each group: group A and control groups B and C. The tumor nodules were injected with Ad-VEGF-siRNA in group A, an equal dose of Ad-EGFP and PBS, respectively, in groups B and C. The volume and weight of tumors were measured every two days after injection and the growth curves were drawn. The tumor samples were observed and analyzed using HE staining. Angiogenesis was assessed by immunohistochemical staining using anti-VEGF and CD31 antibodies. The ultrastructure of vasculogenic mimicry (VM) was observed using transmission electron microscopy (TEM). RESULTS: The mean volume, weight, microvessel density (MVD) and VEGF expression of tumors in Ad-VEGF-siRNA-treated group were significantly lower than those in the control groups. MVD was positively correlated to VEGF expression, with a correlation coefficient of 0.9989. The number of VM was 1.40+/-0.55 in the Ad-VEGF-siRNA group, which was significantly less than those in the two control groups. CONCLUSION: Ad-VEGF-siRNA could effectively block angiogenesis in osteosarcoma xenografts in nude mice.

Inhibitory effects of VEGF-siRNA mediated by adenovirus on osteosarcoma-bearing nude mice.

As one of the blood-rich malignancies, the growth and metastasis of osteosarcoma both depend on its angiogenesis, a procedure in which vascular endothelial growth factor (VEGF) acts essentially. Although with the advent of neoadjuvant chemotherapy, more aggressive surgical excision and logical therapy strategy, the 5-year survival rate remains relatively stable at 70%, at best. However, antiangiogenic therapeutics, through gene silencing and targeting key sequences, probably brings an outlook to the conventional algorithm. In our current research, human-specific VEGF-siRNA (small interfering RNA) mediated by adenovirus was constructed and a cell line of MG63 was cultured and used to make an osteosarcoma-bearing nude mice model. The recombined adenovirus vector of Ad-VEGF-siRNA could successfully suppress VEGF expression and slow down the multiplication of MG63 cells in vivo; likewise, the down regulation of VEGF could be detected in vitro of the animal model. Inhibitory effects on osteosarcoma growth and blockage of pulmonary metastasis could be observed in the following oncotherapy procedure. The study demonstrates potent growth and pulmonary metastasis inhibitory effects of VEGF-siRNA on osteosarcoma in vivo and in vitro, which could potentially be applicable to the treatment of cancers as an antiangiogenic therapeutic in the near future.

[Effect of EPHA2-siRNA plasmid on biological behavior of human osteosarcoma cells in vitro].

OBJECTIVE: To investigate the role of EPHA2 in regulating apoptosis, proliferation and vasculogenic mimicry of osteosarcoma cells, by gene silencing through RNA interference. METHODS: EPHA2-siRNA plasmids were achieved by gene cloning. The plasmids were transfected into human osteosarcoma cells (MG63). The expression level of EPHA2 protein was measured by Western blotting. The proliferation, apoptosis and vasculogenic mimicry features of osteosarcoma MG63cells were assessed by light microscopy, MTIP assay, flow cytometry, annexin V-FITC/PI and HE staining, respectively. RESULTS: The EPHA2-siRNA plasmid was confirmed by DNA sequencing. After treatment with Sequence-specific siRNA targeted EPHA2, the protein level of the transfected group decreased significantly. As compared to non-siRNA transfected cells, the transfected group showed lower proliferation, higher and earlier apoptosis and less osteosarcoma-generated vasculogenic mimicry. CONCLUSION: EPHA2 gene may be involoved in apoptosis and proliferation of osteosarcoma cells, and may be necessary for vasculogenic mimicry. Down-regulation of EPHA2 expression by sequence-specific siRNA may be considered as a new option in the treatment of EPHA2 over-expressing cancer including osteosarcoma in future.

Tumor blood vessels formation in osteosarcoma: vasculogenesis mimicry.

BACKGROUND: Osteosarcoma is characterized by high neovascularization and a high propensity for metastasis through bloodstream. This study was to examine whether there is evidence for vasculogenic mimicry in osteosarcoma and to illustrate mechanism of tumor blood vessels formation in osteosarcoma. METHODS: Osteosarcoma cell lines (U-2OS) were tested for their ability to form tubular networks in three-dimensional culture containing type I collagen. The structures of the tubular networks were observed with phase contrast microscope and transmission electron microscope (TEM). Morphometric studies using hematoxylin and eosin (HE) stain and CD31 immunohistochemical stain to show tumor-lined channels in human osteosarcoma were also performed. RESULTS: Observation with light microscope and TEM showed that highly aggressive osteosarcoma cell lines (U-2OS) formed networks containing channels when grown in three-dimensional culture containing type I collagen, in the absence of endothelial cells or fibroblasts. Morphometric observation using HE stain and CD31 immunohistochemical stain showed that tumor cell-lined channels were also detected in vivo in osteosarcoma; by comparison, all vascular areas in the pedicle of osteochondroma or outside osteochondroma were endothelial-lined. CONCLUSION: These observations strongly suggest that aggressive osteosarcoma cells may generate vascular channels that facilitate tumor perfusion independent of tumor angiogenesis and have the ability of vasculogenic mimicry.