Search

In this work, the medium containing ionic products of dicalcium silicates (Ca2SiO4) for culturing MG63 cells was prepared by immersing a titanium alloy plate with the plasma sprayed Ca2SiO4 coatings in DMEM solution. The effect of the ionic products on cellular differentiation, collagen production, and local growth factors (prostaglandin E2 [PGE2] and transforming growth factor-β [TGF-β1]) of osteoblast-like MG63 cells were investigated. The normal DMEM was also used to culture MG63 cells as the control group. Differentiation of cell was evaluated by detecting alkaline phosphatase (ALP) activity and osteocalcin (OC) synthesis as well as their gene expression. Collagen production was analyzed by Sircol assay. The levels of PGE2 and TGF-β1 in culture medium were measured using enzyme-linked immunosorbent assay (ELISA). The gene expressions of TGF-β receptors (TGF-β RI and TGF-β RII) were also measured by real-time PCR technology. MG63 cells cultured in DMEM containing ionic products of Ca2SiO4 coating showed enhanced differentiation and increased collagen production. The results obtained from ELISA showed that the levels of PGE2 and TGF-β1 in experimental group were higher than that in control. The gene expression of TGF-β receptors was upregulated, indicating that more TGF-β1 bonded to their receptors which produce more effects on the osteoblastic activity, leading to enhanced differentiation and synthetic activity of osteoblast. It is concluded that ionic products of Ca2SiO4 coating may enhance cellular differentiation and collagen production by influencing TGF-β1 pathway. [ABSTRACT FROM AUTHOR]

Abstract: The medium containing ionic products of dicalcium silicate (Ca2SiO4) for culturing the osteoblast-like cells (MG63) were prepared by immersing the plasma sprayed Ca2SiO4 coatings in DMEM solution for 24h. The normal DMEM was also used to culture the MG63 cells as the control group. The results obtained from this work showed that the proliferation of MG63 cell was more significant in the group containing ionic products of Ca2SiO4 coatings than in the control group. The cell cycle distribution indicated that the decreased G0/G1 phase and increased S phase occurred in the cells cultured in the DMEM containing ionic products of Ca2SiO4 coatings. The analysis of osteogenic genes indicated that the ionic products of Ca2SiO4 coating enhanced the expression of osteoblast-related genes and promote differentiation of MG63 cells at initial period. Moreover, the ionic products of Ca2SiO4 coating differentially regulated osteoclastogenic gene expression by up-regulated OPG and down-regulated RANKL. [Copyright &y& Elsevier]

Abstract: This work aims to explore the influence of the ionic products of dicalcium silicate coating on osteoblastic proliferation and differentiation, as well as on the expression of BMP2 and its signal transducers Smad1, 6 and 7 in MG-63 osteoblast-like cells. Plasma-sprayed dicalcium silicate coatings were soaked in DMEM to obtain culture media containing the ionic dissolution products of dicalcium silicate coating (Ca2SiO4–DMEM). MG63 osteoblast-like cells were cultured in Ca2SiO4–DMEM (experimental group) for 3–12 days, while those cultured in normal DMEM served as control (control group). MTT assay was used to evaluate cell viability and proliferation. Alkaline phosphatase activity (ALP), osteocalcin (OC) and type I collagen (COLI) were investigated as differentiation markers. Gene expression of BMP2 and Smad1, 6, 7 was also detected. BMP2 protein was examined by ELISA assay. Alizarin Red-S (AR-S) assay was used to detect mineralization. The results demonstrated that Si concentration in Ca2SiO4–DMEM is markedly higher than that in normal DMEM. Compared to the control group, MG63 cells of the experimental group exhibited upregulated proliferation on day 3, and markedly upregulated gene expression of the differentiation markers, especially on days 9 and 12 for OC and on days 3, 6 and 9 for ALP. Gene expression of BMP2 and Smad1, as well as BMP2 protein secreted into culture media, was also upregulated in the experimental group, while gene expression of Smad6 and 7 was not influenced. AR-S assay indicated a higher calcium mineral content deposition in cells of the experimental group. In conclusion, the ionic products of plasma-sprayed dicalcium silicate coating are beneficial to the proliferation and differentiation of MG63 osteoblast-like cells. [Copyright &y& Elsevier]

Osteolytic disorders are characterized by impaired bone volume and trabecular structure that leads to severe fragility fractures. Studies have shown that excessive osteoclast activity causes impaired bone microstructure, a sign of osteolytic diseases such as osteoporosis. Approaches of inhibiting osteoclastogenesis and bone resorption specifically could prevent osteoporosis and other osteolytic disorders. Acacetin is a potent molecule extracted from plants with anti-cancer and anti-inflammatory bioactivities. Here, we demonstrated, for the first time, that acacetin repressed osteoclastogenesis, formation of F-actin rings, bone resorption activity, and osteoclast-related gene expression in vitro through modulating ERK, P38, and NF-κB signaling pathways and preventing expression of NFATc1. Micro-CT and H & E staining results indicated that acacetin alleviated LPS-induced osteolysis in vivo. Overall, our findings suggested that acacetin could help to prevent osteoporosis and other osteoclast-related osteolytic disorders. • Excessive osteoclastogenesis leads to osteoporosis and other osteoclast-related bone disorders. • Acacetin inhibited RANKL-induced osteoclast formation in vitro without apparent cytotoxicity. • Acacetin negatively regulated osteoclast marker genes expression and NFATc1 expression. • Acacetin substantially suppressed ERK, P38, and NF-κB signaling pathways. • Acacetin alleviated the LPS-induced osteolysis in vivo [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) have been reported to be critical players in osteosarcoma (OS). Among numerous cancer-related miRNAs, the expression level of miR-92a and its potential role in OS has not been investigated. Here, We showed that overexpression of miR-92a was identified in OS specimens and cells compared to normal bone tissues. The high level of miR-92a was correlated with high T classification and advanced clinical stages of OS patients. Notably, miR-92a highly expressing OS patients showed a notably reduced survival rate. In vitro experiments showed that loss of miR-92a inhibited U2OS cell proliferation and cell-cycle progression while induced apoptosis. In turn, its restoration facilitated MG-63 cell growth and suppressed apoptosis. Experimental nude mice showed that miR-92a silencing prohibited the in vivo growth of OS cells. Furthermore, bioinformatics software predicted that F-box and WD repeat-containing protein 7 (FBXW7) was a direct target of miR-92a. We then observed the negative regulation of miR-92a on FBXW7 expression and the direct binding between them was further verified by dual-luciferase assays in OS cells. Forced expression of FBXW7 resulted in reduced proliferation, cell cycle arrest at G1 phase and increased apoptosis in miR-92a overexpressing MG-63 cells. In summary, this study demonstrates miR-92a probably functions as a driver of tumor progression by targeting FBXW7, and highlights the potential effects of miR-92a on prognosis and treatment of OS. [ABSTRACT FROM AUTHOR]