Identification of potential crucial genes associated with vasculogenic mimicry in human osteosarcoma based on gene expression profile

We previously reported the presence of vasculogenic mimicry (VM) in human osteosarcoma. However, the mechanistic basis of osteosarcoma VM remains unclear. Three hundred eighty-one upregulated differentially expressed genes (DEGs) and 526 downregulated DEGs between human osteosarcoma cell line 143B and HOS cell exposed to Matrigel were screened out by microarray. GO categories such as "cell adhesion", "angiogenesis" were enriched in 143B group. PATHWAY analysis showed enriched TGF-beta, Wnt and VEGF signaling pathway in 143B group. The hub gene ITGA2 in signal-network of DEGs exhibited pro-VM and pro-metastasis effect. Our study provides fundamental data for further studies regarding molecules involved in osteosarcoma VM.

Gene therapy of bone morphogenetic protein for periodontal tissue engineering

BACKGROUND

The reconstruction of lost periodontal support including bone, ligament, and cementum is a major goal of therapy. Bone morphogenetic proteins (BMPs) have shown much potential in the regeneration of the periodontium. Limitations of BMP administration to periodontal lesions include need for high-dose bolus delivery, BMP transient biological activity, and low bioavailability of factors at the wound site. Gene transfer offers promise as an alternative treatment strategy to deliver BMPs to periodontal tissues.

METHODS

This study utilized ex vivo BMP-7 gene transfer to stimulate tissue engineering of alveolar bone wounds. Syngeneic dermal fibroblasts (SDFs) were transduced ex vivo with adenoviruses encoding either green fluorescent protein (Ad-GFP or control virus), BMP-7 (Ad-BMP-7), or an antagonist of BMP bioactivity, noggin (Ad-noggin). Transduced cells were seeded onto gelatin carriers and then transplanted to large mandibular alveolar bone defects in a rat wound repair model.

RESULTS

Ad-noggin treatment tended to inhibit osteogenesis as compared to the control-treated and Ad-BMP-7-treated specimens. The osseous lesions treated by Ad-BMP-7 gene delivery demonstrated rapid chrondrogenesis, with subsequent osteogenesis, cementogenesis and predictable bridging of the periodontal bone defects.

CONCLUSION

These results demonstrate the first successful evidence of periodontal tissue engineering using ex vivo gene transfer of BMPs and offers a new approach for repairing periodontal defects.

Effects of geometry of hydroxyapatite as a cell substratum in BMP-induced ectopic bone formation

Three different types of porous hydroxyapatite with pore sizes of 100-200 micrometer in diameter-porous particles of hydroxyapatite (PPHAP), porous blocks of hydroxyapatite (PBHAP), and honeycomb-shaped hydroxyapatite (HCHAP)-were compared in terms of their abilities to induce osteogenesis when implanted subcutaneously with recombinant human BMP-2 into rats and extracted at 1, 2, 3, and 4 weeks. Histologically, direct bone formation occurred in PPHAP and PBHAP while only endochondral ossification took place in HCHAP. Interestingly, cartilage in the central zones and bone in the orifice zones of the tunnels of the HCHAP were observed at 2 weeks. After 3 weeks, the cartilage disappeared and bone formation occurred throughout the inner surface of the tunnels of the HCHAP, always leaving space for capillaries within the tunnels. Alkaline phosphatase activity and osteocalcin content were the highest in HCHAP among the three hydroxyapatite implants. These results clearly indicate that BMP-induced bone formation is highly dependent on the geometry of the carrier, which provides feasible structural factors for vascularization.