Transcription factor scleraxis vitally contributes to progenitor lineage direction in wound healing of adult tendon in mice.

Tendon is a dense connective tissue that transmits high mechanical forces from skeletal muscle to bone. The transcription factor scleraxis (Scx) is a highly specific marker of both precursor and mature tendon cells (tenocytes). Mice lacking scx exhibit a specific and virtually complete loss of tendons during development. However, the functional contribution of Scx to wound healing in adult tendon has not yet been fully characterized. Here, using ScxGFP-tracking and loss-of-function systems, we show in an adult mouse model of Achilles tendon injury that paratenon cells, representing a stem cell antigen-1 (Sca-1)-positive and Scx-negative progenitor subpopulation, display Scx induction, migrate to the wound site, and produce extracellular matrix (ECM) to bridge the defect, whereas resident tenocytes exhibit a delayed response. Scx induction in the progenitors is initiated by transforming growth factor ß (TGF-ß) signaling. scx-deficient mice had migration of Sca-1-positive progenitor cell to the lesion site but impaired ECM assembly to bridge the defect. Mechanistically, scx-null progenitors displayed higher chondrogenic potential with up-regulation of SRY-box 9 (Sox9) coactivator PPAR-γ coactivator-1α (PGC-1α) in vitro, and knock-in analysis revealed that forced expression of full-length scx significantly inhibited Sox9 expression. Accordingly, scx-null wounds formed cartilage-like tissues that developed ectopic ossification. Our findings indicate a critical role of Scx in a progenitor-cell lineage in wound healing of adult mouse tendon. These progenitor cells could represent targets in strategies to facilitate tendon repair. We propose that this lineage-regulatory mechanism in tissue progenitors could apply to a broader set of tissues or biological systems in the body.

Magnetic resonance imaging and thallium-201 scintigraphy for the diagnosis of localized pigmented villonodular synovitis arising from the elbow: A case report and review of the literature.

Pigmented villonodular synovitis (PVNS) arising from the elbow joint is extremely rare; only 24 cases have been reported. It is extremely difficult to differentiate PVNS from other soft tissue tumors on the basis of imaging findings alone. Therefore, a biopsy is required for definitive diagnosis. A 20-year-old female reported a mass on her right elbow. Physical examination revealed a tumor measuring 3.0x3.0 cm. Magnetic resonance imaging (MRI) revealed that the signal intensity of the tumor was isointense to muscle on T1-weighted images; however, it was hyper- or isointense to muscle on T2-weighted images. In images obtained by gadolinium-enhanced MRI, the margin of the tumor was well-contrasted. Thallium (Tl)-201 scintigrams revealed an abnormal accumulation in the area of the mass in the early and delayed phases. On the basis of clinical findings, imaging characteristics and incision biopsy results, localized PVNS was diagnosed and marginal excision was performed. We thus identified an extremely rare case of PVNS arising from the elbow joint. When interpreting Tl-201 images for the assessment of bone and soft tissue lesions, it is important to recognize PVNS as a condition that simulates malignant tumors. Furthermore, PVNS should be considered in the differential diagnosis when increased Tl-201 activity is closely related to the joint. MRI aids in the differentiation by demonstrating features of hemosiderin degradation products. These findings are likely to be extremely helpful in the differential diagnosis of bone and soft tissue tumors.

Chondrosarcoma from the sternum: reconstruction with titanium mesh and a transverse rectus abdominis myocutaneous flap after subtotal sternal excision.

BACKGROUND: Chondrosarcoma arising from the sternum is extremely rare and is often untreatable. Removal of the sternum for malignant tumor results in large defects in bone and soft tissue, causing deformity and paradoxical movement of the chest wall and making subsequent repair of the thorax very important. We report a very rare patient with a chondrosarcoma of the sternum who underwent case chest wall resection, followed by reconstruction using a titanium mesh covered with a transverse rectus abdominis myocutaneous (TRAM) flap. CASE REPORT: A 63-year-old man was referred to our hospital with progressively enlarged swelling of his anterior chest wall. Physical examination showed a 2.5×2.0 cm mass fixed to the sternum, which was diagnosed as a chondrosarcoma based on clinical findings, imaging characteristics and incision biopsy results. The patient underwent a subtotal sternal and chest wall resection to remove the tumor, followed by reconstruction with a titanium mesh and a TRAM flap. There were no complications associated with surgery. CONCLUSIONS: We report an extremely rare case of a patient who underwent subtotal sternal resection, followed by reconstruction, for a large chondrosarcoma. The elasticity and rigidity provided by the titanium mesh and the complete coverage of the surgical wound by a TRAM flap suggest that these procedures may be useful in reconstructing large defects in the chest wall.

Musculoskeletal diseases--tendon.

INTRODUCTION: Tendons establish specific connections between muscles and the skeleton by transferring contraction forces from skeletal muscle to bone thereby allowing body movement. Tendon physiology and pathology are heavily dependent on mechanical stimuli. Tendon injuries clinically represent a serious and still unresolved problem since damaged tendon tissues heal very slowly and no surgical treatment can restore a damaged tendon to its normal structural integrity and mechanical strength. Understanding how mechanical stimuli regulate tendon tissue homeostasis and regeneration will improve the treatment of adult tendon injuries that still pose a great challenge in today's medicine. SOURCE OF DATA: This review summarizes the current status of tendon treatment and discusses new directions from the point of view of cell-based therapy and regenerative medicine approach. We searched the available literature using PubMed for relevant original articles and reviews. GROWING POINTS: Identification of tendon cell markers has enabled us to study precisely tendon healing and homeostasis. Clinically, tissue engineering for tendon injuries is an emerging technology comprising elements from the fields of cellular source, scaffold materials, growth factors/cytokines and gene delivering systems. AREAS TIMELY FOR DEVELOPING RESEARCH: The clinical settings to establish appropriate microenvironment for injured tendons with the combination of these novel cellular- and molecular-based scaffolds will be critical for the treatment.

Conversion of mechanical force into TGF-ß-mediated biochemical signals.

Mechanical forces influence homeostasis in virtually every tissue [1, 2]. Tendon, constantly exposed to variable mechanical force, is an excellent model in which to study the conversion of mechanical stimuli into a biochemical response [3-5]. Here we show in a mouse model of acute tendon injury and in vitro that physical forces regulate the release of active transforming growth factor (TGF)-ß from the extracellular matrix (ECM). The quantity of active TGF-ß detected in tissue exposed to various levels of tensile loading correlates directly with the extent of physical forces. At physiological levels, mechanical forces maintain, through TGF-ß/Smad2/3-mediated signaling, the expression of Scleraxis (Scx), a transcription factor specific for tenocytes and their progenitors. The gradual and temporary loss of tensile loading causes reversible loss of Scx expression, whereas sudden interruption, such as in transection tendon injury, destabilizes the structural organization of the ECM and leads to excessive release of active TGF-ß and massive tenocyte death, which can be prevented by the TGF-ß type I receptor inhibitor SD208. Our findings demonstrate a critical role for mechanical force in adult tendon homeostasis. Furthermore, this mechanism could translate physical force into biochemical signals in a much broader variety of tissues or systems in the body.

High Efficacy of Preoperative Low-Dose Radiotherapy with Sanazole (AK-2123) for Extraskeletal Ewing's Sarcoma: A Case Report.

Extraskeletal Ewing's sarcoma is a rare soft tissue tumor that is morphologically indistinguishable from Ewing's sarcoma of bone. We report a case of extraskeletal Ewing's sarcoma with several systemic problems. A 69-year-old man presented with a 5-month history of a rapidly enlarging mass in the right thigh. Because preoperative radiotherapy with sanazole (AK-2123) contributed the tumor mass reduction down to 40% in size, the tumor was successfully resected with clear surgical margins and repaired with a musculocutaneous flap. The high efficacy of pre-operative low-dose radiotherapy with sanazole was histologically confirmed that the resected tumor specimen involved no viable tumor cells and showed 100% necrosis. Based on clinical outcomes in this case, the combined modality of pre-operative low-dose radiotherapy with hypoxic cell radiosensitizer and adequate surgical resection might provide for the useful clinical application of extraskeletal Ewing's sarcoma treatment.

Combined effects of bisphosphonate and radiation on osteosarcoma cells.

UNLABELLED: Antitumour effects of third-generation bisphosphonates (BPs), such as zoledronic acid (ZOL), and the combined effects of ZOL with other anticancer agents against osteosarcoma cells have been reported previously. The aim of this study was to identify further combined antitumour effects using BPs and radiation in osteosarcoma cell lines. MATERIALS AND METHODS: Cell proliferation, cell cycle analysis, and nuclear morphology were examined in each osteosarcoma cell line divided into three groups (ZOL alone, radiation alone and the ZOL/radiation combination). RESULTS: Combined therapy (low-concentration ZOL and low-dose radiation) had significant growth inhibitory effects compared to the use of ZOL or radiation individually. Flow cytometric analysis revealed an increase in cells in the sub-G(1) phase by combined treatment, and apoptotic cells were also observed. CONCLUSION: These findings suggest that combination therapy using BPs and radiation may be a promising therapy for osteosarcoma, producing fewer side effects and complications in the near future.

A novel MEK1/2 inhibitor induces G1/S cell cycle arrest in human fibrosarcoma cells.

Blockade of the ERK pathway has antitumor effects against malignant tumor cells. In this study, we investigated the antitumor activity of JTP-70902, a novel specific MEK inhibitor, against human fibrosarcoma cells in which the ERK pathway is constitutively activated. JTP-70902 was synthesized at Japan Tabacco. Human fibrosarcoma HT1080 cells were cultured. JTP-70902 was added at various concentrations. The number of viable cells was counted employing a trypan blue dye exclusion test. Unsynchronized cells were exposed to JTP-70902 for 24 h. The nuclei were stained with propidium iodide. The DNA content was measured using a FACSCalibur flow cytometer. Protein extraction and Western blot analysis were performed. (1) A dose-dependent inhibition of cell growth was observed at concentrations of 10 nM or more. Forty-eight hours after the treatment, the growth of HT1080 cells was completely inhibited by 200 nM JTP-70902. (2) FACS analysis revealed that a 24-h exposure to JTP-70902 increased the population of G1/S phase cells in a dose-dependent manner. (3) The phosphorylation of ERK was inhibited by JTP-70902. Furthermore, after the treatment with JTP-70902, p21WAF1/CIP1 and p27KIP1 protein expression increased and the phosphorylation of RB was reduced. Our results showed that JTP-70902 inhibits cell growth and induces cell cycle arrest in human Ras mutant fibrosarcoma cells. These results indicate that JTP-70902 might be an attractive compound for molecular-targeting chemotherapy for malignant soft tissue tumors with the activation of the Ras-MEK-ERK pathway.

Zoledronic acid inhibits proliferation of human fibrosarcoma cells with induction of apoptosis, and shows combined effects with other anticancer agents.

Third-generation bisphosphonates are known to inhibit bone resorption and also appear to exhibit direct anti-tumour activity. We previously reported that third-generation bisphosphonates such as zoledronic acid (ZOL) have a direct antitumour effect, and synergistically augment the effects of antitumor agents in osteosarcoma cells. There has been no report on the antitumor effect of ZOL against soft tissue sarcoma. The aim of this study was to evaluate the antitumor effect of this drug on a human fibrosarcoma cell line, in terms of proliferation and apoptosis, and, moreover, to evaluate the combined effects of ZOL with other antitumor drugs against the human fibrosarcoma cell line. HT1080 cells were treated with ZOL at various concentrations up to 10 microM, and then cell proliferation, cell cycle, nuclear morphology, and Western blot analyses were performed to study the antitumor effects of ZOL alone, and, moreover, HT1080 cells were treated with ZOL and other anticancer drugs such as paclitaxel, docetaxel, doxorubicin, etoposide, 5-fluorouracil, gemcitabine, cisplatin, or methotrexate to investigate the combined effects using proliferation and cell cycle analyses. We found that ZOL strongly inhibited in vitro proliferation, arrested the cell cycle between S and G2/M phases, and induced the apoptosis of human fibrosarcoma cells. Moreover, ZOL augmented the effect of antitumor agents when administered concurrently with paclitaxel, docetaxel, doxorubicin, etoposide, 5-fluorouracil, gemcitabine, and cisplatin in human fibrosarcoma cells. The treatment of fibrosarcoma with ordinary antitumor drugs is not fully effective. These findings suggest that ZOL directly affects the proliferation and survival of fibrosarcoma cells, and that the combined administration of ZOL with other antitumor agents may improve the efficacy of fibrosarcoma treatment. These results support the possibility that their combined use could be beneficial in the treatment of patients not only with various types of cancer or osteosarcoma, but also with soft tissue sarcoma.

Clinically relevant dose of zoledronic acid inhibits spontaneous lung metastasis in a murine osteosarcoma model.

Clinically obtainable concentrations of zoledronic acid (ZOL) inhibited the production of vascular endothelial growth factor and reduced the migration, adhesion, and invasiveness of osteosarcoma (OS) cells in vitro. The in vivo effects of ZOL were investigated by using a murine model of spontaneous lung metastasis. The higher dose of ZOL (80 microg/kg three times/week) inhibited the growth of OS at the primary site, accompanied by inhibition of neovascularization in the tumor. Interestingly, while the lower dose of ZOL (80 microg/kg once a week) could not inhibit the growth of OS at the primary site, it significantly prevented lung metastasis.

Evaluation of clinical outcomes and prognostic factors for synovial sarcoma arising from the extremities.

BACKGROUND: Synovial sarcoma is an uncommon tumor and remains a disease with poor prognosis. Although several prognostic factors have been previously reported, prognostic factors associated with synovial sarcoma are conflicting. This study was undertaken to evaluate our institutional clinical outcomes and to determine prognostic factors for synovial sarcoma. MATERIAL/METHODS: A series of 17 patients with synovial sarcoma arising from the extremities surgically treated between September 1979 and April 2005 was analyzed retrospectively. Data regarding patient age, sex, primary tumor site, primary tumor size, histologic subtype, management of primary tumor (surgery, chemotherapy, radiotherapy), microscopic surgical margins, previous treatment at other hospitals for synovial sarcoma and follow-up information were recorded. Furthermore, statistical analysis of survival rates and prognostic variables were examined. RESULTS: The mean and median follow-up time were 82.4 months and 79.0 months, respectively. Seven of 17 patients (41.2%) initially underwent inappropriate unplanned surgery at other hospitals. The surgical margins of the definitive surgery at our hospital were adequate in all patients. The local recurrence and metastasis rates after definite surgery with adequate surgical margins at our hospital were 5.9% and 35.3%, respectively. The 5-year and 10-year overall survival rates were 88.2% and 79.4%, respectively. A statistically significant adverse prognostic factor was undergoing initial surgical resection at other hospitals (p=0.02). CONCLUSIONS: Initial surgical treatment with adequate surgical margins by experienced surgeons for synovial sarcomas, preferably at specialized hospitals, should be considered to increase local control and improve outcome and survival.

Sulforaphane induces cell cycle arrest and apoptosis in murine osteosarcoma cells in vitro and inhibits tumor growth in vivo.

Sulforaphane (SFN), a naturally occurring isothiocyanate, is an attractive agent due to its potent anticancer effects. SFN suppresses the proliferation of various cancer cells in vitro and in vivo. In this study, we report that SFN inhibited the proliferation of cultured murine osteosarcoma LM8 cells. Twenty micromolar SFN completely inhibited the growth of LM8 cells and caused G2/M-phase arrest. SFN induced the expression of p21(WAF1/CIP1) protein causing the cell cycle arrest in a dose-dependent manner. SFN induced apoptosis which was characterized by the appearance of cells with sub-G1 DNA content and the cleavage and activation of caspase-3. We showed that SFN induced the growth arrest and up-regulated the expression of p21(WAF1/CIP1) protein in a p53-independent manner in human osteosarcoma MG63 cells. We found that intraperitoneal administration of SFN (1 or 2 mg, 5 times/week) significantly inhibited the growth of LM8 xenografts to <30% of the controls in a preclinical animal model without causing any toxicity. In osteosarcoma cells, our findings provide in vivo evidence for the efficacy of SFN against the advanced growth of tumor. We showed that SFN induces cell cycle arrest and apoptosis in osteosarcoma cells and inhibits tumor xenograft growth. Furthermore, SFN is a potent inducer of p21(WAF1/CIP1) in osteosarcoma cells. These results raise the possibility that SFN may be a promising candidate for molecular-targeting chemotherapy against osteosarcoma.

The plant alkaloid cryptolepine induces p21WAF1/CIP1 and cell cycle arrest in a human osteosarcoma cell line.

We previously established a bioassay method to screen for compounds that activate the promoter activity of p21(WAF1/CIP1), a potent inhibitor of cyclin-dependent kinases, in a p53-independent manner. As an activator of p21(WAF1/CIP1) promoter activity, we isolated cryptolepine (CLP: 5-methyl indolo (2,3b)-quiniine), an indoloquinoline alkaloid, from the traditional Ayurvedic medicinal plant Sida cordifolia. We show here that CLP induces the expression of p21(WAF1/CIP1) with growth arrest in p53-mutated human osteosarcoma MG63 cells. Four micromolar of CLP completely inhibited the growth of MG63 cells and caused G2/M-phase arrest. CLP up-regulated the expression of p21(WAF1/CIP1) at both mRNA and protein levels in a dose-dependent manner. Using several mutant p21(WAF1/CIP1) promoter constructs, we found that the CLP-responsive element is an Sp1 site at -82 relative to the transcription start site of the p21(WAF1/CIP1) promoter. These findings suggest that CLP arrests the growth of MG63 cells by activating the p21(WAF1/CIP1) promoter through the specific Sp1 site in a p53-independent manner. In addition, CLP-mediated cell cycle arrest was reduced by the knockout of the p21(WAF1/CIP1) gene in human colon cancer HCT116 cells, suggesting that the cell cycle arrest by CLP was at least partially mediated through the induction of p21(WAF1/CIP1) expression. Although we need further study of chemotherapeutic effect in vivo, these results raise the possibility that CLP might be a suitable chemotherapeutic agent for treatment of osteosarcoma.

Life expectancy and functional prognosis after femoral neck fractures in hemodialysis patients.

OBJECTIVES: To identify whether differences exist in the outcomes between patients undergoing hemodialysis and elderly nonhemodialysis patients with a femoral neck fracture. DESIGN: Retrospective review. SETTING: Level 1 trauma center. PATIENTS/INTERVENTIONS: A total of 71 femoral neck fractures in 62 patients undergoing hemodialysis treated nonoperatively or operatively. MAIN OUTCOME MEASUREMENTS: Clinical outcomes were analyzed to identify factors that may be correlated with life expectancy and functional prognosis. RESULTS: The overall survival rates in this study at 1-year and 5-years postfracture were found to be 89.8% and 51.5%, respectively. There were significant correlations among the survival rate, patients' age, type of treatment, prefracture ambulation status, and prefracture activities of daily living status. However, using multivariate analysis, the only significant predictor of life expectancy was prefracture ambulation status. As for functional prognosis, the rates of total ambulation recovery and total activities of daily living recovery at 1-year postfracture were 50.0% and 71.2%, respectively. Both patients' age and age at the onset of hemodialysis may contribute considerably to functional prognosis in patients undergoing hemodialysis after femoral neck fracture. CONCLUSIONS: The present study suggests that the clinical outcomes of patients with femoral neck fractures who undergo hemodialysis are considerably superior to those of previous studies. In addition, when those fractures are treated surgically with specific management in patients undergoing hemodialysis, it may be possible to expect a life expectancy and functional prognosis similar to elderly nonhemodialysis patients with hip fractures.

Sulforaphane enhances TRAIL-induced apoptosis through the induction of DR5 expression in human osteosarcoma cells.

Sulforaphane (SFN), a naturally occurring isothiocyanate, is an attractive agent because of its potent anticancer effects. SFN suppresses the proliferation of various cancer cells in vitro and in vivo. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is also one of the most promising candidates for cancer therapeutics owing to its ability to selectively induce apoptosis in tumor cells. In this study, we report that SFN enhances TRAIL-induced apoptosis in human osteosarcoma cells, Saos2 and MG63. The apoptosis induced by co-treatment with SFN and TRAIL was markedly blocked by a dominant negative form of the TRAIL receptor or caspase inhibitors. The combined use of SFN and TRAIL effectively induced Bid cleavage and the activation of caspases 8, 10, 9 and 3 at ineffective concentrations for each agent. SFN upregulated the expression of death receptor 5 (DR5), a receptor for TRAIL, at mRNA and protein levels in a dose-dependent manner. In addition, the SFN-mediated sensitization to TRAIL was reduced by DR5 siRNA, suggesting that the sensitization was at least partially mediated through the induction of DR5 expression. Furthermore, SFN sensitized TRAIL-induced apoptosis in a p53-independent manner. On the other hand, SFN neither induced DR5 protein expression or enhanced TRAIL-induced apoptosis in normal human peripheral blood mononuclear cells. Thus, combined treatment with SFN and TRAIL might be a promising therapy for osteosarcoma.