PURPOSE: Bone metastasis invariably increases morbidity and mortality. This study compares the effects of ibandronate and paclitaxel on bone structure and its mechanical properties and biochemical turnover in resorption markers using an immunocompetent Walker 256-Sprague-Dawley model, which was subjected to tumor-induced osteolysis. MATERIALS AND METHODS: Seventy rats were divided equally into 4 groups: 1) sham group (SHAM), 2) tumor group (CANC), 3) ibandronate treated group (IBAN), and 4) paclitaxel treated group (PAC). Morphological indices [bone volume fraction (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp)] and mechanical properties (failure load, stiffness) were evaluated after thirty days of treatment period. Bone resorption rate was analysed using serum deoxypyridinoline (Dpd) concentrations. RESULTS: Morphological indices showed that ibandronate (anti-resorptive drug) had a better effect in treating tumor-induced architectural changes in bone than paclitaxel (chemotherapeutic drug). The deterioration in bone architecture was reflected in the biomechanical properties of bone as studied with decreased failure load (F(x)) and stiffness (S) of the bone on the 30th day postsurgery. Dpd concentrations were significantly lower in the IBAN group, indicating successful inhibition of bone resorption and destruction. CONCLUSION: Ibandronate was found to be as effective as higher doses of paclitaxel in maintaining stiffness of bone. Paclitaxel treatment did not appear to inhibit osteoclast resorption, which is contrary to earlier in-vitro literature. Emphasis should be placed on the use of immunocompetent models for examining drug efficacy since it adequately reflects bone metastasis in clinical scenarios.
Amino Acids ; Animals ; Biomechanical Phenomena/*drug effects/physiology ; Bone Density/drug effects/physiology ; Bone Neoplasms/*drug therapy ; Bone Resorption/*chemically induced ; Diphosphonates/*pharmacology ; Immunocompetence ; Male ; *Neoplasm Metastasis ; *Osteolysis ; Paclitaxel/*pharmacology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo observe the effect and mechanisim of zoledronate sodium on periprosthetic osteolysis in rat induced by polyethylene particles.

METHODSTotal 30 adult male SD rats, weighting from 250 to 300 g, were selected and randomly divided into three groups: blank control group, model control group and zoledronate sodium group respectively, 10 animals for each group. No treatment was performed in the blank control group. In model control group and zoledronate sodium group, the modle of periprosthetic osteolysis in rats were made by implanting polyethylene particles and titanium rods into their right femurs. After operation, rats in zoledronate sodium group were administered with zoledronate sodium (0.1 mg/kg each week) through subcutaneous injection for 8 weeks, then the blood was obtained and all experimental animals were sacrificed to get the right femur specimens. The femur BMD, IL-1β, IL-6, TNF-α, serum TRACP5b and CTX-I were detected.

RESULTSCompared with the model control group, the femur BMD was increased, while IL-1β, IL-6 and TNF-α were all decreased in zoledronate sodium group; the serum TRACP5b and CTX-I level were both reduced in zoledronate sodium group.

CONCLUSIONThe zoledronate sodium could effectively inhibit periprosthetic osteolysis in rats induced by polyethylene particles, which might be realized by inhibiting the activity of osteoclasts and the expression of IL-1β, IL-6 and TNF-α. It provides a new method to treat periprosthetic osteolysis of the artificial joint prosthesis.

Animals ; Bone Density ; drug effects ; Collagen Type I ; analysis ; Cytokines ; analysis ; Diphosphonates ; therapeutic use ; Imidazoles ; therapeutic use ; Joint Prosthesis ; Male ; Osteolysis ; drug therapy ; Peptides ; analysis ; Polyethylene ; pharmacology ; Rats ; Rats, Sprague-Dawley

Zoledronic acid has been used for prevention of osteolytic and osteoblastic bone metastasis. This case report illustrates an undesirable consequence from prolonged usage of zoledronic acid in bone metastasis prevention. Periprosthetic acetabular fracture in a patient treated with zoledronic acid for 7 years was reported. The clinical presentation, radiographic and pathological results were described. This is a rare complication after total hip arthroplasty which should not be ignored especially in patients who received long term bisphosphonate.
Acetabulum/*injuries/pathology/surgery ; Aged ; Arthroplasty, Replacement, Hip/*adverse effects ; Bone Density Conservation Agents/*adverse effects/pharmacology ; Bone Neoplasms/prevention & control/secondary ; Bone Remodeling/drug effects ; Breast Neoplasms/pathology ; Diphosphonates/*adverse effects/pharmacology ; Female ; Fractures, Spontaneous/chemically induced/etiology ; Hip Prosthesis ; Humans ; Imidazoles/*adverse effects/pharmacology ; Osteoarthritis, Hip/*surgery ; Periprosthetic Fractures/*chemically induced/etiology ; Prosthesis Failure ; Reoperation

In this study, the rescue effect of receptor activator for nuclear factor-kappaB ligand (RANKL) on zoledronate acid (ZOL) induced inhibition of osteoclastogenesis and gene expression of NF-kappaB p50 and c-Jun was investigated. Mice calvarial osteoblasts (OBs) were harvested and co-cultured with RAW264.7 cells and the cells were divided into 4 groups and received treatment with ZOL and RANKL, either single or combined. The formation of multi-nucleated osteoclast (OC) was examined and gene expression of NF-kappaB p50 and c-Jun was detected. Group B (ZOL) showed least multi-nucleated OC and resorption lacunae among the 4 groups (P < 0.05 or P < 0.01) and it was followed by group C (ZOL+RANKL). Group D (RANKL) showed highest OC and resorption lacunae while it was similar to Group A (control) (P > 0.05). Gene expression of NF-kappaB p50 and c-Jun was the lowest in group B (P < 0.05 or P < 0.01) among the four groups and was significantly increased in group C when compared with group B (P < 0.05). Group A and D showed highest gene expression and they were similar to each other (P > 0.05). This study suggest that RANKL might partly rescue ZOL induced inhibition of osteoclastogenesis, and the effect of RANKL and ZOL on osteoclastogenesis may be mediated by NF-kappaB p50 and c-Jun.
Animals ; Bone Resorption ; drug therapy ; Cell Line ; Diphosphonates ; pharmacology ; Gene Expression ; Imidazoles ; pharmacology ; Mice ; NF-kappa B p50 Subunit ; metabolism ; Osteoblasts ; drug effects ; Osteoclasts ; drug effects ; Proto-Oncogene Proteins c-jun ; metabolism ; RANK Ligand ; pharmacology

OBJECTIVETo explore the effect of zoledronate (ZOL) on osteoclast differentiation and expressions of transient receptor potential vanilloid 5 channel (TRPV5) and nuclear factor of activated T-cells cytoplasmic 1 (NFATc1).

METHODSRAW264.7 cells were divided into two groups for treatment with RANKL for 5 days (group A) or with additional ZOL treatment in the last 2 days of RANKL treatment (group B). Osteoclastogenesis of the cells and the mRNA and protein expressions of TRPV5 and NFATc1 after the treatments were examined.

RESULTSIn group B, the number of newly generated osteoclasts (≥ 3 nuclei), number and size of dentin resorption lacunaes were 29.0 ± 2.4, 24.8 ± 1.1, and 2 030.0 ± 165.7 µm², respectively, which were significantly lower than those in group A (56.5 ± 4.5, 49.3 ± 0.9, and 3 946.7 ± 367.5 µm², respectively, P<0.01). Fluorescent intensity of TRPV5 and NFATc1 were also significantly decreased in group B (P<0.01). Compared with those in group A, TRPV5 mRNA and protein expressions in group B were down-regulated by 50.4% and 37.8%, and those of NFATc1 by 68.0% and 48.4%, respectively (P<0.01).

CONCLUSIONZOL can significantly inhibit osteoclastogenesis and bone resorption, which may be attributed, at least partly, to ZOL-induced inhibition of TRPV5 and NFATc1 expressions.

Animals ; Bone Resorption ; Calcium Channels ; metabolism ; Cell Differentiation ; drug effects ; Cell Line ; Diphosphonates ; pharmacology ; Down-Regulation ; Imidazoles ; pharmacology ; Mice ; NFATC Transcription Factors ; metabolism ; Osteoclasts ; drug effects ; RANK Ligand ; pharmacology ; RNA, Messenger ; TRPV Cation Channels ; metabolism

BACKGROUNDGrowing preclinical evidence shows that zoledronic acid (ZOL) exhibits direct antitumor activity in various cancer cell lines. However, the cytotoxic effects of ZOL on human hepatocellular carcinoma (HCC) cells have not been established. In the present study, we investigated the effect of ZOL on HCC both in vitro and in vivo.

METHODSCytotoxicity and cell cycles were assessed with Sulforhodamine B colorimetric assay and flow cytometry. Expression levels of cell cycle phase-linked proteins were examined. The effect of ZOL on HCC in vivo was explored based on H22-subcutaneous injection (s.c.) and H22-intraperitoneal injection (i.p.) mice model.

RESULTSZOL inhibited the growth of SK-HEP-1 and H22 cells and induced S-phase arrest through downregulating cdc2 protein and upregulating cyclin A. It inhibited the growth of s.c tumors, and increased the survival of both H22-s.c. and H22-i.p. mice in vivo.

CONCLUSIONZOL inhibits growth of HCC cells in vitro and in vivo.

Animals ; Carcinoma, Hepatocellular ; drug therapy ; pathology ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Diphosphonates ; pharmacology ; therapeutic use ; Female ; Humans ; Imidazoles ; pharmacology ; therapeutic use ; Liver Neoplasms ; drug therapy ; pathology ; Mice ; Xenograft Model Antitumor Assays

BACKGROUNDBisphosphonates (BPs) have been reported to reduce local recurrence in giant cell tumor (GCT) of bone because of their osteoclast-suppressing effect; however, the optimal mode of delivery and the dose and duration of treatment of BPs remain to be established. To address these issues, it is first necessary to clarify the manner of action of BPs on osteoclasts. We herein evaluated the osteoclast-suppressing effect of sodium ibandronate in vitro.

METHODSMouse osteoclasts (OCLs) were generated in vitro using mouse bone marrow mononuclear cells. First, various concentrations of sodium ibandronate and equal amounts of phosphate-buffered saline were added to cell culture media. The number of multinucleated cells (over three nuclei) was recorded in each group, OCL formation was compared, and the most effective concentration of sodium ibandronate was determined. Then, high concentrations of sodium ibandronate were added to the experimental cell culture media; no ibandronate was given in the control group. Comparisons were made between the two groups in terms of OCL adhesion, migration, and bone resorption.

RESULTSOCL formation was suppressed by sodium ibandronate in vitro; the most pronounced effect was observed at the concentration of 10(-5) mol/L. OCL migration and bone resorption were significantly suppressed at this concentration, though there was no effect on OCL adhesion.

CONCLUSIONSSodium ibandronate was effective in suppressing OCLs and decreasing resorption in GCT. The strong anti-OCL effectiveness at a high concentration in vitro indicates a topical mode of application.

Animals ; Bone Resorption ; Cell Movement ; drug effects ; Cells, Cultured ; Diphosphonates ; pharmacology ; Mice ; Osteoclasts ; cytology ; drug effects

Bisphosphonate-Associated Osteonecrosis of the Jaw ; diagnosis ; etiology ; prevention & control ; therapy ; Diphosphonates ; chemistry ; pharmacokinetics ; pharmacology ; Humans ; Risk Factors

Activated protein C (APC) is a cytoprotective anticoagulant that can promote cutaneous healing. We examined the effect of APC on viability and differentiation of the osteoblastic line, MG63, in the presence and absence of bisphosphonates (BPs). Osteoblasts were cultured and treated for 24 or 48 h with Alendronate (Aln), Zoledronate (Zol) or Pamidronate (Pam) at concentrations ranging from 10-4 to 10-6 M. Cell differentiation was measured using type 1 collagen production, Alizarin red staining and alkaline phosphatase activity, whereas cell viability was assessed using MTT and crystal violet assays. All three BPs induced MG63 cell death in a dose- and time-dependent manner. Pam- and Zol-related cell death was prevented by APC treatment; however, cell death induced by Aln was accelerated by APC. APC induced MG63 cell differentiation that was enhanced by Aln, but inhibited by Pam or Zol. Endothelial protein C receptor (EPCR) was expressed by MG63 cells and mediated the protective effect of APC on Zol-induced viability. In summary, we have demonstrated that (1) APC favorably regulates MG63 viability and differentiation toward bone growth, (2) APC differentially regulates the effects of specific BPs and (3) at least part of the effects of APC is mediated through EPCR. These findings highlight the potential importance of the PC pathway in bone physiology and provide strong evidence that APC may influence bone cells and has potential to be a therapeutic drug for bone regeneration, depending on concurrent BP treatment.
Antigens, CD/metabolism ; Caspases/metabolism ; Cell Differentiation/*drug effects ; Cell Survival/drug effects ; Collagen Type I/metabolism ; Diphosphonates/*pharmacology ; Extracellular Signal-Regulated MAP Kinases/metabolism ; Humans ; Matrix Metalloproteinase 2/metabolism ; NF-kappa B/metabolism ; Osteoblasts/*cytology/*drug effects/enzymology ; Protein C/*pharmacology ; Receptors, Cell Surface/metabolism ; Up-Regulation/drug effects

Bisphosphonates are used routinely to reduce bone-related events in breast cancer patients with bone metastasis. We evaluated the effects of zoledronic acid, a third generation, nitrogen-containing bisphosphonate, to prevent bone metastasis in breast cancer. Zoledronic acid or vehicle alone was administered to nude mice either simultaneously or after intracardiac injection of human breast cancer MDA-MB-231 cells. Nude mice treated with zoledronic acid at early time points showed a lower incidence of bone metastases than did vehicle-treated nude mice, but these differences were not statistically significant. Only 37.5% of mice treated with zoledronic acid at the time of tumor cell inoculation developed bone metastases compared to over 51.8% of mice receiving vehicle alone (P = 0.304). Cell count of apoptosis confirmed by immunohistochemical staining in metastatic bone tissue significantly increased in the zoledronic acid-treated groups compared to non-treated group (1,018.3 vs 282.0; P = 0.046). However, metastatic tumor cells, which invade soft tissue around the bone, did not show extensive apoptosis; there were no differences between the zoledronic acid-treated and control groups. These results suggest that zoledronic acid increases apoptosis of metastatic breast tumor cells in the bone and could therefore reduce metastatic tumor burden. These results support the use of zoledronic acid to reduce the incidence of bone metastasis in breast cancer.
Animals ; Apoptosis/drug effects ; Bone Density Conservation Agents/pharmacology ; Bone Neoplasms/prevention & control/*secondary ; Bone and Bones/drug effects/pathology ; Breast Neoplasms/*drug therapy/*pathology ; Diphosphonates/*pharmacology ; Female ; Humans ; Imidazoles/*pharmacology ; Mice ; Mice, Nude ; Xenograft Model Antitumor Assays