The effect of bone morphogenetic protein-7 on the expression of type I inositol 1,4,5-trisphosphate receptor in G-292 osteosarcoma cells and primary osteoblast cultures

MiR-193a regulates chemoresistance of human osteosarcoma cells via repression of IRS2

Chemoresistance prevents curative potential of chemotherapy in most cases. MicroRNAs (miRNAs) are key players in regulating chemoresistance in osteosarcoma, which is the most common primary bone cancer. Bisulfite sequencing and quantitative real time PCR analyses showed that miR-193a expression is downregulated by DNA hypermethylation at its promoter region in a chemoresistant cell line, SJSA-1, compared to a chemosensitive cell line G-292. Introduction of a miR-193a mimic in SJSA-1 cells or an antagomir into G-292 cells confirmed the role of miR-193a in osteosarcoma chemoresistance. Bioinformatics together with biochemical assays showed that insulin receptor substrate 2 (IRS2) is a target of miR-193a. Our data concludes that miR-193a plays a role in the osteosarcoma chemoresistance and thus might serve as a useful biomarker for osteosarcoma prognosis.

TGF-β Family Signaling in Mesenchymal Differentiation

Mesenchymal stem cells (MSCs) can differentiate into several lineages during development and also contribute to tissue homeostasis and regeneration, although the requirements for both may be distinct. MSC lineage commitment and progression in differentiation are regulated by members of the transforming growth factor-β (TGF-β) family. This review focuses on the roles of TGF-β family signaling in mesenchymal lineage commitment and differentiation into osteoblasts, chondrocytes, myoblasts, adipocytes, and tenocytes. We summarize the reported findings of cell culture studies, animal models, and interactions with other signaling pathways and highlight how aberrations in TGF-β family signaling can drive human disease by affecting mesenchymal differentiation.

The miR-34a-5p promotes the multi-chemoresistance of osteosarcoma via repression of the AGTR1 gene

Background

Chemoresistance hinders the curative cancer chemotherapy. MicroRNAs (miRNAs) are key players in diverse biological processes including the chemoresistance of cancers.

Methods

A RNA-seq-based miR-omic analysis of osteosarcoma (OS) cells was performed to detect the levels of miR-34a-5p. Bioinformatics analysis revealed that AGTR1 is one of the target genes of miR-34a-5p. The mRNA and protein levels of AGTR1 were detected in both the miR-34a-5p-mimic transfected G-292 and miR-34a-5p-antagomiR transfected SJSA-1 cells. The involvement of AGTR1 with OS chemoresistance was validated by the experiments with siRNA-mediated repression or overexpression of the AGTR1 gene.

Results

We showed that miR-34a-5p promotes the multi- chemoresistance of OS. The angiotensin II type 1 receptor (AGTR1) gene, is one of the targets of miR-34a-5p in OS and thus negatively correlates with OS chemoresistance by systematic investigations of a multi-drug sensitive (G-292) and resistant (SJSA-1) OS cell lines. Down-regulation of the AGTR1 expression by siRNA passivates G-292 cells and suppresses cell apoptosis, while over-expression of AGTR1 sensitizes SJSA-1 cells and thus promotes the drug-triggered cell death.

Conclusions

The miR-34a-5p and its target gene AGTR1 are the potential targets for an effective chemotherapy of OS. Our results also provide novel insights into the effective chemotherapy for OS patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-3002-x) contains supplementary material, which is available to authorized users.

Titanium dioxide nanotube films: Preparation, characterization and electrochemical biosensitivity towards alkaline phosphatase

Titania nanotubes (TNTs) were prepared by anodization on different substrates (titanium, Ti6Al4V and Ti6Al7Nb alloys) in ethylene glycol and glycerol. The influence of the applied potential and processing time on the nanotube diameter and length is analyzed. The as-formed nanotube layers are amorphous but they become crystalline when subjected to subsequent thermal treatment in air at 550°C; TNT layers grown on titanium and Ti6Al4V alloy substrates consist of anatase and rutile, while those grown on Ti6Al7Nb alloy consist only of anatase. The nanotube layers grown on Ti6Al7Nb alloy are less homogeneous, with supplementary islands of smaller diameter nanotubes, spread across the surface. Better adhesion and proliferation of osteoblasts was found for the nanotubes grown on all three substrates by comparison to an unprocessed titanium plate. The sensitivity towards bovine alkaline phosphatase was investigated mainly by electrochemical impedance spectroscopy in relation to the crystallinity, the diameter and the nature of the anodization electrolyte of the TNT/Ti samples. The measuring capacity of the annealed nanotubes of 50nm diameter grown in glycerol was demonstrated and the corresponding calibration curve was built for the concentration range of 0.005-0.1mg/mL.

Prostaglandin production by human gingival fibroblasts inhibited by triclosan in the presence of cetylpyridinium chloride

BACKGROUND

The effect of triclosan plus the cationic detergent cetylpyridinium chloride (CPC) was evaluated for prostaglandin inhibition in human gingival fibroblasts. Since triclosan has previously been shown to inhibit proinflammatory cytokine induced prostaglandin E2 (PGE2) production, we wanted to determine if triclosan, in the presence of CPC, could enhance these effects.

METHODS

Initial studies determined that both triclosan and CPC were cytotoxic to human gingival fibroblasts in concentrations exceeding 1.0 microg/ml for either agent longer than 24 hours in a tissue culture. Therefore, subsequent studies measuring prostaglandin biosynthesis and cyclooxygenase (COX)-1 and COX-2 mRNA expression were performed in concentrations and times that did not significantly affect cell viability.

RESULTS

PGE2 biosynthesis was dose dependently inhibited by both triclosan and triclosan and CPC when challenged by tumor necrosis factor (TNF)-alpha or interleukin (IL)-1beta. At pharmacologically relevant concentrations, triclosan and CPC inhibited IL-1beta-induced PGE2 production to a greater extent than triclosan alone (P = 0.02). Moreover, enhanced COX-2 mRNA repression was observed with triclosan and CPC in comparison to triclosan alone in IL-1beta and TNF-alpha stimulated cells. No effect on COX-1 gene expression was observed. Further analysis of cell signaling mechanisms of triclosan and CPC indicates that nuclear factor-kappa B (NF-kappaB) and not p38 mitogen-activated protein kinase (MAPK) signaling may be impaired in the presence of triclosan and CPC.

CONCLUSION

This study indicates that triclosan and CPC are more effective at inhibiting PGE2 at the level of COX-2 gene regulation, and this combination may offer a potentially better anti-inflammatory agent in the treatment of inflammatory lesions in the oral cavity.

Characterization and bond strength of electrolytic HA/TiO2 double layers for orthopaedic applications

Insufficient bonding of juxtaposed bone to an orthopaedic/dental implant could be caused by material surface properties that do not support new bone growth. For this reason, fabrication of biomaterials surface properties, which support osteointegration, should be one of the key objectives in the design of the next generation of orthopaedic/dental implants. Titanium and titanium alloy have been widely used in several bioimplant applications, but when implanted into the human body, these still contain some disadvantages, such as poor osteointegration (forming a fibrous capsule), wear debris and metal ion release, which often lead to clinical failure. Electrolytic hydroxyapatite/titanium dioxide (HA/TiO2) double layers were successfully deposited on titanium substrates in TiCl4 solution and subsequently in the mixed solution of Ca(NO3)2 and NH4H2PO4, respectively. After annealing at 300 degrees C for 1 h in the air, the coated specimens were evaluated by dynamic cyclic polarization tests, immersion tests, tensile tests, surface morphology observations, XRD analyses and cells culture. The adhesion strength of the HA coating were improved by the intermediate coating of TiO2 from 11.3 to 46.7 MPa. From cell culture and immersion test results, the HA/TiO2 coated specimens promoted not only cells differentiation, but also appeared more bioactive while maintaining non-toxicity.

Characterization and bond strength of electrolytic HA/TiO2 double layers for orthopedic applications

Insufficient bonding of juxtaposed bone to an orthopedic/dental implant could be caused by material surface properties that do not support new bone growth. For this reason, fabrication of biomaterials surface properties, which support osteointegration, should be one of the key objectives in the design of the next generation of orthopedic/dental implants. Titanium and titanium alloy have been widely used in several bioimplant applications, but when implanted into the human body, these still contain some disadvantages, such as poor osteointegration (forming a fibrous capsule), wear debris and metal ion release, which often lead to clinical failure. Electrolytic hydroxyapatite/titanium dioxide (HA/TiO2) double layers were successfully deposited on titanium substrates in TiCl4 solution and subsequently in the mixed solution of Ca(NO3)2 and NH4H2PO4, respectively. After annealing at 300 degrees C for 1 h in the air, the coated specimens were evaluated by dynamic cyclic polarization tests, immersion tests, tensile tests, surface morphology observations, XRD analyses and cells culture. The adhesion strength of the HA coating were improved by the intermediate coating of TiO2 from 11.3 to 46.7 MPa. From cell culture and immersion test results, the HA/TiO2 coated specimens promoted not only cells differentiation, but also appeared more bioactive while maintaining non-toxicity.

Differential expression of myosin heavy-chain mRNA in muscles of mastication during functional advancement of the mandible in pigs

Surgical and orthodontic treatment of retrognathia aims to improve orofacial function by adaptation and training of muscle capacity, which is connected with a change in muscle fibre-type proportions. The aim here was to analyse the proportion of myosin-heavy chain (MyHC) gene expression in type I (slow twitch/ST) and type IIb (fast twitch/FT) fibres during sagittal advancement of the mandible by reverse transcriptase-polymerase chain reaction (RT-PCR). The experiments were carried out on 10-week-old pigs (six test animals, six controls) over a 28-day period. Six pigs were fitted with acrylic bite blocks for sagittal advancement of the mandible. Tissue was taken from seven different regions of the masseter, temporal, medial pterygoid, and geniohyoid muscles. The 84 samples were used for histological fibre differentiation with ATPase staining and for isolation of total RNA. To measure the two MyHC isoforms, RT-PCR (in a single tube reaction with MyHC I, MyHC IIb, and GAPDH primers) was used. A significant increase was registered in the percentage of ST fibres and in mRNA from MyHC I in the anterior region of the masseter and in the posterior region of the temporal muscle of the treated animals. The proportion of ST fibres to FT fibres was increased by up to 12% after functional advancement of the mandible. The histological findings corresponded with the data for fibre mRNA generated by RT-PCR.