MG63 Proliferation Research Articles

MicroRNA-205 acts as a tumor suppressor in osteosarcoma via targeting RUNX2.

MicroRNAs (miRs) are a class of small non-coding RNAs, and negatively regulate gene expression through directly binding to the 3'-untranslational region (UTR) of their target mRNA, which further leads to translational repression or mRNA degradation. Recently, various miRs have been implicated in the development and progression of osteosarcoma (OS). However, the underlying mechanism has not been fully uncovered. Our study aimed to reveal the exact role of miR-205 in OS, as well as the regulatory mechanism. In this study, we found that the expression of miR-205 was significantly reduced in a total of 34OS tissue specimens compared to their matched adjacent normal tissues. Besides, it was also remarkably downregulated in OS cell lines (Saos-2, U2OS, SW1353, and MG63) compared to human osteoblast hFOB1.19 cells. Overexpression of miR-205 caused a significant decrease in the proliferation, migration and invasion of MG63 and U2OS cells. Runt-related transcription factor2 (RUNX2) was further identified as a target gene of miR-205. Moreover, the mRNA and protein expression of RUNX2 was reduced after miR-205 overexpression, but increased after knockdown of miR-205 in MG63 and U2OS cells. Furthermore, overexpression of RUNX2 effectively reversed the suppressive effect of miR-205 on the proliferation, migration, and invasion of MG63 and U2OS cells. The RUNX2 level was significantly increased in OS tissues compared to their matched adjacent normal tissues, as well as in OS cell lines compared to hFOB1.19 cells. In addition, the RUNX2 level was reversely correlated with the miR-205 level in OS tissues. Taken together, our data demonstrate that miR-205 acts as a tumor suppressor in OS via directly targeting RUNX2. Therefore, we suggest that the miR-205/RUNX2 axis may serve as a potential target for the treatment of OS.

MiR-421 is a diagnostic and prognostic marker in patients with osteosarcoma.

MicroRNAs (miRNAs) are a new class of prognostic and diagnostic biomarkers for many cancers. Recent studies have shown that miRNAs are highly stable in plasma/serum. The aim of this study was to investigate the role of miR-421 in osteosarcoma. We found that the serum expression levels of miR-421 were significantly higher in osteosarcoma patients than those in healthy volunteers. Moreover, miR-421 expression was significantly higher in osteosarcoma tissues compared with that in the adjacent normal tissues. Meanwhile, the expression of miR-421 was upregulated in 90% (36/40) osteosarcoma tissues compared to non-tumor tissues. More importantly, the expression levels of miR-421 in osteosarcoma tissues were correlated with those in patients' serum. In addition, patients with high miR-421 expression had shorter overall survival (OS) than those with low expressions. We also found that overexpression of miR-421 promoted osteosarcoma cell line MG-63 proliferation, migration, and invasion. In conclusion, miR-421 expression levels were upregulated in osteosarcoma tissue and serum and it may be a useful marker for diagnosis of osteosarcoma.

The synergistic anticancer effect of cisplatin combined with Oldenlandia diffusa in osteosarcoma MG-63 cell line in vitro.

BackgroundOldenlandia diffusa (OD) is a well-known traditional Chinese medicine, which is used to prevent and treat many disorders, especially cancers. However, its role in osteosarcoma has not been well understood. Here, we used OD and cisplatin individually and combined in osteosarcoma MG-63 cell to explore whether OD could induce cellular apoptosis and suppress the ability of proliferation and invasion of osteosarcoma MG-63 cell.MethodsThe changes of cellular shape were analyzed by optical microscopy. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay was used to analyze cell survival rate in vitro. Flow cytometry was performed to detect cell cycle and cell death. Scratch migration assay was used to evaluate cell migration and invasion. Western blot was performed to determine the expression levels of pro-apoptotic and anti-apoptotic protein.ResultsIn this study, we found that the survival rate reduced significantly in the combined group compared with the individual group and control group. The apoptosis-inducing effect of combined application was much more significant than that of individual application. The invasion ability of combined application was significantly lower than that of the individual application. In the combined group, there were high expression levels of pro-apoptotic protein and low expression of anti-apoptotic protein. Cell-cycle analysis showed a change in the cell-cycle distribution and arrested cells in G2-M phase.ConclusionIn this study, we found that OD inhibited proliferation and induced apoptosis in the human osteosarcoma MG-63 cell line in a time-dependent and dose-dependent manner. In addition, OD displayed inhibitory activity on MG-63 cell proliferation and invasion and the study also showed that OD activity might be mediated by caspase activation. These data suggest that OD might represent a novel, efficient candidate agent for further experimentation in osteosarcoma treatment.

Antioxidant and bone repair properties of quercetin-functionalized hydroxyapatite: An in vitro osteoblast–osteoclast–endothelial cell co-culture study

Quercetin (3,3′,4′,5,7–pentahydroxy-flavone) is a flavonoid known for its pharmacological activities, which include antioxidant and anti-inflammatory properties, as well as possible beneficial action on diseases involving bone loss. In this work, we explored the possibility to functionalize hydroxyapatite (HA) with quercetin in order to obtain new materials for bone repair through local administration of the flavonoid. HA was synthesized in presence of different concentrations of quercetin according to two different procedures: direct synthesis and phase transition from monetite. Direct synthesis lead to composite nanocrystals containing up to 3.1wt% quercetin, which provokes a reduction of the crystals mean dimensions and of the length of the coherently scattering domains. Synthesis conditions provoke a partial oxidation of quercetin and, as a consequence, a significant reduction of its radical scavenging activity (RSA). On the other hand, synthesis through phase transition yields samples containing up to 1.3wt% of quercetin incorporated into hydroxyapatite, with minor structural modifications, which exhibit relevant anti-oxidant activities, as testified by their high RSA levels, (slightly lower than that of pure quercetin). The biological response to these materials was tested using an innovative triculture model involving osteoblast, osteoclast and endothelial cells, in order to mimic bone microenvironment. The results show that the presence of quercetin in the composite materials enhances human osteoblast-like MG63 proliferation and differentiation, whereas it downregulates osteoclastogenesis of osteoclast precursors 2T-110, and supports proliferation and differentiation of human umbilical vein endothelial cells (HUVEC). Statement of SignificanceThe pharmacological activities of the flavonoid quercetin include anti-oxidant and antiinflammatory properties, as well as capability to prevent bone loss. In this paper, we demonstrate that it is possible to synthesize hydroxyapatite functionalized with different amounts of quercetin and obtain new composite materials which display both the good bioactivity of the inorganic phase and the therapeutic properties of the flavonoid. The innovative in vitro model developed in this study, which involves co-culture of osteoblast, osteoclast and endothelial cells, allows to state that the new materials exert a beneficial action onto bone repair microenvironment, stimulating osteoblast proliferation and activity, downregulating osteoclastogenesis, and supporting microangiogenetic processes necessary for new bone formation.

Effect of porous titanium coated with IGF-1 and TGF-β1 loaded gelatin microsphere on function of MG63 cells

Porous titanium with porosity of 60% was prepared by metal injection molding (MIM), and coated with gelatin sustained-release microspheres which were made by improved emulsified cold condensation method. The effects of porous titanium coated with insulin-like growth factor-1 (IGF-1) and transforming growth factor-β1 (TGF-β1) gelatin microspheres on the function of MG63 cells were evaluated in vitro. The results show that porous titanium coated with gelatin sustained-release microspheres has no cytotoxicity. The IGF-1 and TGF-β1 loading concentrations are positively correlative with the proliferation and differentiation of MG63 after co-culturing with the concentrations of IGF-1 and TGF-β1 gelatin microspheres in the range of 0.1–10 ng/mg and 0.25–2.5 ng/mg, respectively. The MG63 cells exhibit the best proliferation and differentiation with the IGF-1 and TGF-β1 loading concentrations of 10 ng/mg and 2.5 ng/mg, respectively. The joint application of IGF-1 and TGF-β1 group, which promote adhesion, proliferation and differentiation of MG63 cells, is superior to a single application group.

Biological Effect of Ultraviolet Photocatalysis on Nanoscale Titanium with a Focus on Physicochemical Mechanism.

Physicochemical properties, regulated by various surface modifications, influence the biological performance of materials. The interaction between surface charge and biomolecules is key to understanding the mechanism of surface-tissue integration. The objective of this study was to evaluate the biological response to a nanoscale titanium surface after ultraviolet (UVC, λ = 250 ± 20 nm) irradiation and to analyze the effects via a physicochemical mechanism. The surface characteristics were evaluated by field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, surface profilometry, and contact angle assay. In addition, we applied the zeta-potential, a direct method to measure the electrostatic charge on UV-treated and UV-untreated titanium nanotube surfaces. The effect of the Ti surface after UV treatment on the biological process was determined by analyzing bovine serum albumin (BSA) adsorption and osteoblast-like MG-63 early adhesion, morphology, cytoskeletal arrangement, proliferation, and focal adhesion. Compared to an anodized titanium nanotube coating, UV irradiation altered the contact angles on the control surface from 51.5° to 6.2° without changing the surface topography or roughness. Furthermore, titanium nanotubes after UV treatment showed a significant reduction in the content of acidic hydroxyl groups and held less negative charge than the anodized coating. With regard to the biological response, along with an enhanced capability to adsorb BSA, osteoblasts exhibited higher colonization and viability on the UV-treated material. The results suggest that UV treatment enhances the biocompatibility by reducing the electrostatic repulsion between biomaterials and biomolecules.

Enhanced osteoconductivity of polyethersulphone nanofibres loaded with bioactive glass nanoparticles in in vitro and in vivo models.

There is growing need for new scaffold constructions for synthetic bone graft substitutes to repair large bone lesions. A very promising and important class of new implants for tissue engineering is based on three-dimensional scaffolds and bioceramics. In this study, after investigation of mechanical properties of polyethersulphone (PES) nanofibres, fabricated by electrospinning methodology and coated with bioactive glass (BG), cells of the MG-63 line were cultured on surfaces of these scaffolds. Their capacity to support MG-63 proliferation was also investigated in vitro by MTT assay. Osteoconductivity on these scaffolds was investigated by the common osteogenic markers alkaline phosphatase (ALP) activity, calcium mineral deposition and bone-related gene activation. Next, a bone reconstruction of rat critical-size defects model was evaluated using radiographic imaging analysis (digital mammography), computed tomography and histological examination. In vitro results indicated that biocompatibility and osteogenic markers of MG-63 cells were significantly enhanced after coating PES with BG. Based on in vivo results, new bone formation in the defect site was enhanced in implanted rats in comparison with a control group. The highest reconstruction was observed in animals implanted with BG-coated nanofibres. Osteoconductivity of PES nanofibres was markedly enhanced after coating them with BG, and introduction of this construct as new bone-graft substitute for bone loss and defects is indicated.

Molecular mechanisms of Polyphyllin I-induced apoptosis and reversal of the epithelial–mesenchymal transition in human osteosarcoma cells

Osteosarcoma is a most common highly malignant bone tumor in children and adolescents. Polyphyllin I (PPI) is an ethanol extraction from Paris polyphylla Smith var.yunnanensis (Franch.) Hand.-Mazz, which belongs to antipyretic-detoxicate family and has been used as a natural medicine in the treatment of infectious disease and cancer in China for centuries. The proteasome activity inhibitory and anti-osteosarcoma effects of PPI have not been known. Here we found PPI exhibited a selective inhibitory effect on proteasomal chymotrypsin (CT)-like activity, both in purified human proteasome and in cultured osteosarcoma cellular proteasome, and caused an accumulation of ubiquitinated proteins. PPI also inhibited viability, proliferation, migration, and invasion of MG-63, Saos-2, and U-2 OS osteosarcoma cells and resulted in S phase arrest and apoptosis. Furthermore, we explored the molecular targets involved. Exposure of osteosarcoma cells to PPI caused an inactivation of the intrinsic nuclear factor κB (NF-κB) and activation of unfolded protein response (UPR)/endoplasmic reticulum (ER) stress signaling cascade in osteosarcoma cells, followed by down-regulation of anti-apoptotic proteins, with up-regulation of pro-apoptotic proteins. We also demonstrated down-regulation of c-Myc, Cyclin B1, Cyclin D1, and CDK1, which are involved in the cell cycle and growth. Finally, we identified down-regulation of Vimentin, Snail, Slug, and up-regulation of E-cadherin, which are integral proteins involved in epithelial–mesenchymal transition (EMT). Taken together, our data provide insights into the mechanism underlying the anticancer activity of PPI in human osteosarcoma cells.

MicroRNA-153 inhibits osteosarcoma cells proliferation and invasion by targeting TGF-β2.

Increasing evidence indicates that microRNAs (miRNAs), a class of small noncoding RNAs, participate in almost every step of cellular processes. MiRNAs are aberrantly expressed in human cancers and contribute to cancer development and progression. Study of miRNAs may provide a new clue for understanding the mechanism of carcinogenesis and a new tool for cancer treatment. In the present study, miR-153 was downregulated in human osteosarcoma tissues and cell lines. Introduction of miR-153 mimics into the MG-63 cells inhibited cell proliferation and invasion. Our results further revealed that transforming growth factor beta 2 (TGF-β2) was negatively regulated by miR-153. Furthermore, overexpression of miR-153 decreased p-SMAD2, p-SMAD3, epidermal growth factor receptor (EGFR) and insulin-like growth factor binding protein-3 (IGFBP-3) expressions, which were the downstream signaling molecules of TGF-β. Furthermore, miRNA-153 suppressed TGF-β-mediated MG-63 proliferation and migration. Therefore, our results suggest that miR-153 may act as a tumor suppressor in osteosarcoma through targeting TGF-β2.

Experimental research of Hedyotic diffusa injection on the inhibition of the proliferation of human osteosarcoma cell line MG-63 in vitro

Objective To investigate the inhibition of Hedyotic diffusa injection on the proliferation of human osteosarcoma cell line MG-63 in vitro. Methods The human osteosarcoma cell line MG-63 was subcultivated aseptically in vitro.Different concentration of Hedyotic diffusa injection(50μL/mL,100μL/mL,200μL/mL,400μL/mL)successively acted on such cell.A total three time points were selected to determine the activity and numbers of cells by MTT assay including 12h,24h and 48h. Results The cellular proliferation inhibition rates of human osteosarcoma cell line MG-63 in drug groups of 50μL/mL concentration holes were(2.87±2.22)%,(13.42±2.14)% and(30.80±3.67)% after 12 h,24 h and 48 h.The rates of 100μL/mL concentration holes were(22.25±1.58)%,(43.34±2.84)% and(66.46±2.64)%,after 12 h,24 h and 48 h.The rates gradually increased and had statistical meaning,t12h= 12.319,t24h= 14.573,t48h = 12.319,P<0.05;the cell in drug groups of 200μL/ml and 400μL/ml concentration holes was totally dead,and pathological findings showed that there were circular and floating cells in which nucleoplasmic ratio decreased and small fragments of cells increased. Conclusion Hedyotic diffusa extract has a certain inhibition in vitro on the proliferation of human osteosarcoma cell line MG-63.Moreover,the strength of its inhibition is relevant probably with drug concentration, which deserves a further research. Key words: Human osteosarcoma cell line MG-63; Cell proliferation; Hedyotic diffusa extract

Zinc ion implantation‑deposition technique improves the osteoblast biocompatibility of titanium surfaces.

The plasma immersion ion implantation and deposition (PIIID) technique was used to implant zinc (Zn) ions into smooth surfaces of pure titanium (Ti) disks for investigation of tooth implant surface modification. The aim of the present study was to evaluate the surface structure and chemical composition of a modified Ti surface following Zn ion implantation and deposition and to examine the effect of such modification on osteoblast biocompatibility. Using the PIIID technique, Zn ions were deposited onto the smooth surface of pure Ti disks. The physical structure and chemical composition of the modified surface layers were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. In vitro culture assays using the MG-63 bone cell line were performed to determine the effects of Zn-modified Ti surfaces following PIIID on cellular function. Acridine orange staining was used to detect cell attachment to the surfaces and cell cycle analysis was performed using flow cytometry. SEM revealed a rough ‘honeycomb’ structure on the Zn-modified Ti surfaces following PIIID processing and XPS data indicated that Zn and oxygen concentrations in the modified Ti surfaces increased with PIIID processing time. SEM also revealed significantly greater MG-63 cell growth on Zn-modified Ti surfaces than on pure Ti surfaces (P<0.05). Flow cytometric analysis revealed increasing percentages of MG-63 cells in S phase with increasing Zn implantation and deposition, suggesting that MG-63 apoptosis was inhibited and MG-63 proliferation was promoted on Zn-PIIID-Ti surfaces. The present results suggest that modification with Zn-PIIID may be used to improve the osteoblast biocompatibility of Ti implant surfaces.

High doses of bisphosphonates reduce osteoblast-like cell proliferation by arresting the cell cycle and inducing apoptosis

ObjectivesThe study objective was to evaluate the effect on osteoblast growth of high concentrations of three nitrogen-containing bisphosphonates (pamidronate, alendronate, and ibandronate) and one non-nitrogen-containing bisphosphonate (clodronate), using the MG-63 cell line as an osteoblast model, in order to determine the role of osteoblasts in bisphosphonate-related osteonecrosis of the jaw (BRONJ). Materials and methodsOsteoblasts were incubated in culture medium with different doses of pamidronate, alendronate, ibandronate or clodronate. The proliferative capacity of the osteoblasts was determined by spectrophotometry (MTT-based) at 24 h of culture. Flow cytometry was used to determine the percentage of cells in each cell cycle phase (G0/G1, G2/M, and S) and to discriminate apoptotic cell death from necrotic cell death in the cell cycle at 24 h of treatment. ResultsAll the bisphosphonates assayed produced a significant and dose-dependent reduction in MG-63 proliferation at the high doses assayed (10−4 and 5 × 10−5 M) in comparison with controls (p <0.001). Cell cycle study revealed that all assayed bisphosphonates significantly arrested the cell cycle in phase G0/G1 at doses of 10−4 and 5 × 10−5 M, increasing the percentage of cells in this phase (p <0.05). Apoptosis/necrosis studies showed significant changes compared with control cells, with an increased percentage of cells in apoptosis after treatment with 10−4 or 5 × 10−5 M of pamidronate, alendronate, ibandronate, or clodronate (p <0.05). ConclusionsHigh doses of nitrogen-containing or non-nitrogen-containing bisphosphonates can reduce the proliferation of MG-63 osteoblast-like cells by arresting the cell cycle and inducing apoptosis/necrosis.

Nitrogen-containing bisphosphonates modulate the antigenic profile and inhibit the maturation and biomineralization potential of osteoblast-like cells.

The aim was to evaluate the effect of three nitrogen-containing bisphosphonates at different concentrations on osteoblast growth, differentiation, and antigenic profile, using the MG-63 cell line as osteoblast model, in order to determine the role of osteoblasts in bisphosphonate-related osteonecrosis of the jaw (BRONJ). Osteoblasts were incubated in culture medium with 10(-5), 10(-7), or 10(-9)M of pamidronate, alendronate, or ibandronate. Proliferative capacity of the osteoblasts was determined by spectrophotometry (MTT) at 24 and 48h of culture. Flow cytometry was used to study antigenic profile (CD54, CD80, CD86, HLA-DR) and phagocytic activity. Cell differentiation was evaluated at 7, 15, and 21days by the study of nodule formation and alkaline phosphatase activity (ALP) at 24h by spectrophotometric assay. Pamidronate, alendronate, and ibandronate each exerted a significant stimulatory effect on MG63 proliferation that depended on the dose and treatment duration (p < 0.05). In general, a significantly decreased expression of CD54, CD80, and HLA-DR membrane antigens was observed after 24h of treatment with each nitrogen-containing bisphosphonate (p < 0.05), but there was no significant difference in phagocytic activity versus controls. A decrease in ALP activity was observed after 24h of treatment and a decrease in calcium deposition after 15 and 21days (p < 0.05). Nitrogen-containing bisphosphonates can increase the proliferation of MG-63 osteoblast-like cells, modulate their expression of co-stimulatory molecules associated with immune function, and decrease their differentiation capacity, generally at low doses. These findings suggest that low doses of nitrogen-containing bisphosphonates exert their effect on osteoblasts by altering their physiology, which would explain the disruption of their repair capacity and may be directly related to the development of BRONJ.

Effects of metformin on proliferation of osteosarcoma MG63 cells and expression of protein protein kinase B and forkhead box transcription factor O1

Objective To investigate the effect of metformin on proliferation of osteosarcoma MG63 cells and protein kinase B (Akt) and forkhead box transcription factor O1 (FoxO1) phosphorylation in Akt signal pathway,and to explore the possible mechanism of metformin inhibiting proliferation of MG63 cells.Methods Osteosarcoma MG63 cells were cultured with RPMI 1640 supplemented with 10％ fatal bovine serun (FBS) untill the cells reached 70％ confluence,and cultured continuously with 50 mmol/L FBS-free RPMI 1640.Cell counting kit-8 (CCK-8) was used to test the proliferation of osteosarcoma cells treated with metformin at 12,24,36,48,and 72 h.After extraction of total protein,the Akt,p-Akt,FoxO1,and p-FoxO1 expression was analyzed by using Western blotting in MG63 cells at 24 h.Results The proliferation of the MG63 cells could be significantly inhibited by metformin in a time-independent manner,and protein Akt and FoxO1 phosphorylation could also be inhibited after 48 h.The p-Akt expression in metformin and control groups was 0.62 ± 0.04 and 1.33 ± 0.16 respectively (P ＜ 0.05).The p-FoxOl expression in metformin and control groups was 0.82 ±0.02 and 1.71 ±0.05 respectively (P ＜ 0.05).Conclusion Metformin can inhibit proliferation of osteosarcoma cells in vitro,which is associated with the dephosphorylation of Akt/FoxO1 signal pathway. Key words: Metformin ; Osteosarcoma; Proliferation; Protein kinase B

Inhibitory effects of curcumin on growth of human osteosarcoma cell line MG-63 cells

Objective To investigate the inhibitory effects of curcumin (Cur) on proliferation and apopotosis of human osteosarcoma cell line MG-63 cells.Methods The cultured MG-63 cells were treated with Cur (12.5,25.0,50.0,100.0 μmol/L) for 12 h.The morphologic changes of MG-63 cells were observed by inverted microscope.The survival rate of MG-63 cells was measured by using methyl thiazol tetrazolium (MTT) assay.Cell counting of kit-8 (CCK-8) assay was used to test the growth inhibitory rate.Annexin V/propidium iodide (PI) staining was applied to detect the apoptosis.The survival ratios and the adhesion capacity of MG-63 were detected except the lactate dehydrogenase (LDH) releasing.Results Different concentrations of Cur (12.5,25.0,50.0,100.0 μmol/L) observed in this study have significant effects on the survival ratio of MG-63.The Cur could significantly inhibit the growth of MG-63 in a dose and time dependent manner and induce G2/M Phase cell cycle arrest.After 12 h,cell inhibition rate of 47.23％,24 h after the cell was 65.23％.Cur 12.5,25.0,50.0,100.0 μmol/L group for 24 h,MG-63 cell apoptosis rate was (11.24 ± 0.07)％,(28.23 ± 0.35)％,(50.21 ± 1.71)％ and (41.22 ±1.85) ％,50.0 μmol/L curcumin could induce apoptosis obviously.Conclusion When Cur increased from 12.5 μmol/L to 25.0 μmol/L,its MG-63 cells at 24h growth inhibition rate (13.56 ± 1.88) ％ to (48.27 ±2.32)％,50.0 μmol/L group 24 h growth inhibition rate to 65.23％.50.0 μmol/L of Cur on the MG-63 cells apoptosis induced by the most obvious,for 24 h,apoptosis rate was (50.21 ± 1.71)％. Key words: Curcumin ; Osteosarcoma; Proliferation

Hydrothermal preparation and characterization of ultralong strontium-substituted hydroxyapatite whiskers using acetamide as homogeneous precipitation reagent.

The ultralong strontium- (Sr-) substituted hydroxyapatite (SrHAp) whiskers were successfully prepared using acetamide as homogeneous precipitation reagent. The effect of the Sr substitution amount on the lattice constants and proliferation of human osteoblast cells (MG-63) was further investigated. The results showed that the SrHAp whiskers with diameter of 0.2–12 μm and ultralong length up to 200 μm were obtained and the Sr substitution level could be facilely tailored by regulating the initial molar ratio of Sr/(Sr + Ca) in raw materials. The Sr2+ replaced part of Ca2+ and the lattice constants increased apparently with the increase of the Sr substitution amount. Compared with the pure HAp whiskers, the Sr substitution apparently stimulated the proliferation of MG-63 at certain extracted concentrations. Our study suggested that the obtained SrHAp whiskers might be used as bioactive and mechanical reinforcement materials for hard tissue regeneration applications.

Different effects of a novel CaO–MgO–SiO2-based multiphase glass–ceramic on cell behaviors of normal and cancer cells in vitro

The effects in vitro of a novel multiphase glass–ceramic (with nominal composition of 43.19% CaO, 7.68% MgO, and 49.13% SiO2 in weight percent) on cell adhesion, proliferation, differentiation and ultrastructure of human osteosarcoma cell line MG63, mouse fibroblasts L929, and human lung adenocarcinoma epithelial cell line A549 were investigated in this research. Scanning electron microscopy (SEM) micrographs revealed that the surface morphology of this glass–ceramic was beneficial to cell adhesion. The glass–ceramic extracts at certain concentrations could stimulate the proliferation and differentiation of MG63 and L929 cells, whereas inhibit A549 proliferation, which might be resulted from the released Si ions. In addition, when cultured with 0.1mg/mL glass–ceramic powder suspension, the cell ultrastructure of MG63 showed abundant organelles and L929 displayed the phenomena of cellular stress response. While more interestingly, A549 exhibited chromatin condensation, mitochondria swell and RER expansion, which was presumed to be early signs of apoptosis. These results suggest that this novel CaO–MgO–SiO2-based multiphase glass–ceramic has potential for bone regeneration and tissue engineering applications.

MicroRNA-128 promotes proliferation in osteosarcoma cells by downregulating PTEN

MicroRNAs are a class of small noncoding RNAs that function as critical gene regulators through targeting mRNAs for translational repression or degradation. Several studies have indicated that abnormal expression of miRNAs occurs frequently in human osteosarcoma. In the present study, we found that miR-128 expression was significantly increased in osteosarcoma tissues compared to adjacent normal tissues. Ectopic overexpression of miR-128 significantly promoted while suppression of miR-128 by its antisense inhibited the proliferation of MG63 and U2OS cells. At the molecular level, our results demonstrated that miR-128 overexpression could repress expression of PTEN by directly targeting PTEN 3'-untranslated region. Consistently, downstream AKT signaling was altered by miR-128 overexpression or knockdown. Therefore, our results suggest that miR-128 plays an important role in the proliferation of human osteosarcoma cells by directly regulation of PTEN/AKT signaling.

A novel ruthenium(II) complex inhibits cell proliferation and induces apoptosis in MG-63 cells

Objective To investigate the effects of a novel ruthenium(Ⅱ) polypyridyl complex △-[Ru (phen)2MCMIP]2 + (△-1) on proliferation and apoptosis of human osteosarcoma cell line MG-63 in vitro.Methods Cell counting of kit-8 (CCK-8) assay was used to detect the proliferation of MG-63 cells after 24,48,72h treatment with △-1 under the concentrations of 0.00,12.50,25.00,50.00,100.00,150.00 μmol/L;Changes of apoptosis and cell cycle in MG-63 cells after 24 h treatment of 0.00,25.00,50.00,100.00 μmol/L A-1 were determined and analyzed by flow cytometry (FCM).Results Ruthenium (Ⅱ) polypyridyl complex A-1 could significantly inhibit the growth of MG-63 in a dose and time dependent manner; the IC50 of 24 h,48 h,72 h was 57.80μmol/L,45.27μmol/L,32.51μmol/L respectively; flow cytometry detection showed that A-1 induced 37.10％ of apoptosis,while only 1.06％ in control group,and arrested cell cycle at G0/G1 phase.Conclusion Ruthenium(Ⅱ) polypyridyl complex A-1 is able to inhibit proliferation and induce apoptosis in MG-63 cells and arrest cell cycle at G0/G1 phase. Key words: Ruthenium(Ⅱ) complex; MG-63 cells; Proliferation; Apoptosis; Cell cycle

Platelets increase while serum reduces the differentiation and activity of osteoclasts in vitro

Platelets modulate formation of osteoclasts and osteoblasts, but research with different preparations of platelets remains inconclusive. Here, we assessed whether serum components modulate the effect of platelet preparations. In murine bone marrow cultures, osteoclastogenesis was investigated in the presence of platelet-released supernatant (PRS), serum containing PRS (SC-PRS), and serum. Osteoclastogenesis was quantified by the numbers of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells, TRAP activity and resorption assays. Also human osteoclastogenesis assays were performed. Viability and proliferation were tested by MTT and (3) [H]thymidine incorporation assays, respectively. Osteoblastogenesis was assessed by histochemical staining for alkaline phosphatase-of murine bone marrow cultures and human MG63 cells. We found PRS to increase the number of TRAP(+) multinucleated cells in the early phase and TRAP activity in the later phase of osteoclastogenesis. SC-PRS and serum decreased the number and activity of TRAP(+) multinucleated cells. Both serum containing preparations reduced viability and proliferation of hematopoietic progenitors. PRS decreased the numbers of alkaline phosphatase-positive colonies while SC-PRS and serum increased osteoblastmarkers in MG63. Proliferation of MG63 was stimulated by all preparations. These results show that activated platelets support osteoclastogenesis, while platelet preparations that contain serum components decrease osteoclastogenesis and increase osteoblastogenesis in vitro, suggesting that serum components modulate the effects of platelets on osteoclastogenesis and osteoblastogenesis.