Satoshi Kamura

Basic fibroblast growth factor in the bone microenvironment enhances cell motility and invasion of Ewing's sarcoma family of tumours by activating the FGFR1-PI3K-Rac1 pathway

Background:Ewings sarcoma family of tumours (ESFT) is a malignant small round-cell tumour of the bone and soft tissues. It is characterised by a strong tendency to invade and form metastases. The microenvironment of the bone marrow is a large repository for many growth factors, including the basic fibroblast growth factor (bFGF). However, the role of bFGF in the invasive and metastatic phenotype of ESFT has not been investigated.Methods:The motility and invasion of ESFT cells were assessed by a wound-healing assay, chemotaxis assay, and invasion assay. The expression and activation of FGF receptors (FGFRs) in ESFT cell lines and clinical samples were detected by RT–PCR, western blotting, and immunohistochemistry. The morphology of ESFT cells was investigated by phase-contrast microscopy and fluorescence staining for actin. Activation of Rac1 was analysed by a pull-down assay.Results:bFGF strongly induced the motility and invasion of ESFT cells. Furthermore, FGFR1 was found to be expressed and activated in clinical samples of ESFT. Basic FGF-induced cell motility was mediated through the FGFR1–phosphatidylinositol 3-kinase (PI3K)–Rac1 pathway. Conditioned medium from bone marrow stromal cells induced the motility of ESFT cells by activating bFGF/FGFR1 signalling.Conclusion:The bFGF–FGFR1–PI3K–Rac1 pathway in the bone microenvironment may have a significant role in the invasion and metastasis of ESFT.

miR-125b develops chemoresistance in Ewing sarcoma/primitive neuroectodermal tumor

BackgroundDiverse functions of microRNAs (miRNAs), including effects on tumorigenesis, proliferation, and differentiation, have been reported, and several miRNAs have also been demonstrated to play an important role in apoptosis. In this study, we investigated the possible role that miRNAs may play in the development of chemoresistance in Ewing sarcoma/primitive neuroectodermal tumor (EWS).MethodsWe screened doxorubicin (Dox)-resistant EWS cells to identify any distinct miRNA sequences that may regulate the chemoresistance of EWS cells. The effects of miRNAs were evaluated using a chemosensitivity assay. The possible target genes of the miRNAs were predicted using a web-based prediction program.ResultsWe found miR-125b to be upregulated in two different Dox-resistant EWS cell lines. The upregulation of miR-125b was also confirmed in the EWS tumors having survived chemotherapy regimen which includes doxorubicin. When miR-125b was knocked down in EWS cells, both the Dox-resistant and parental cells showed an enhanced sensitivity to doxorubicin, which was associated with the upregulation of the pro-apoptotic molecules, p53 and Bak. Inversely, the overexpression of miR-125b in parental EWS cells resulted in enhanced drug resistance, not only to doxorubicin, but also to etoposide and vincristine.ConclusionsOur findings suggest that miR-125b may play a role in the development of chemoresistance in EWS by suppressing the expression of the apoptotic mediators, such as p53 and Bak.

Y-box binding protein-1 regulates cell proliferation and is associated with clinical outcomes of osteosarcoma

Background:Prognosis of osteosarcoma (OS) with distant metastasis and local recurrence is still poor. Y-box binding protein-1 (YB-1) is a multifunctional protein that can act as a regulator of transcription and translation and its high expression of YB-1 protein was observed in OS, however, the role of YB-1 in OS remains unclear.Methods:Y-box binding protein-1 expression in OS cells was inhibited by specific small interfering RNAs to YB-1 (si-YB-1). The effects of si-YB-1 in cell proliferation and cell cycle transition in OS cells were analysed in vitro and in vivo. The association of nuclear expression of YB-1 and clinical prognosis was also investigated by immunohistochemistry.Results:Proliferation of OS cell was suppressed by si-YB-1 in vivo and in vitro. The expression of cyclin D1 and cyclin A were also decreased by si-YB-1. In addition, si-YB-1 induced G1/S arrest with decreased cyclin D1 and cyclin A in OS cell lines. Direct binding of YB-1 in OS cell lines was also observed. Finally, the nuclear expression of YB-1 was significantly related to the poorer overall survival in OS patients.Conclusion:Y-box binding protein-1 would regulate cell cycle progression at G1/S and tumour growth in human OS cells in vitro and in vivo. Nuclear expression of YB-1 was closely associated with the prognosis of OS, thus, YB-1 simultaneously could be a potent molecular target and prognostic biomarker for OS.

Role of the VEGF-Flt-1-FAK pathway in the pathogenesis of osteoclastic bone destruction of giant cell tumors of bone

BackgroundGiant cell tumors (GCTs) of bone are primary benign bone tumors that are characterized by a high number of osteoclast-like multinuclear giant cells (MNCs). Recent studies suggest that the spindle-shaped stromal cells in GCTs are tumor cells, while monocyte-like cells and MNCs are reactive osteoclast precursor cells (OPCs) and osteoclasts (OCs), respectively. In this study, we investigated the pathogenesis of osteoclastic bone destruction in GCTs by focusing on the role of the vascular endothelial growth factor (VEGF)-Flt-1 (type-1 VEGF receptor)-focal adhesion kinase (FAK) pathway.MethodsThe motility of OPCs cells was assessed by a chemotaxis assay and the growth of OPCs was examined using a cell proliferation assay. The expression of VEGF and activation of Flt-1 and FAK in clinical GCT samples and in OPCs were detected by immunohistochemistry and immunoblotting. The correlation between the expression levels of activated Flt-1 and FAK and clinical stages of GCTs was investigated by immunohistochemistry.ResultsIn GCT samples, CD68, a marker of OPCs and OCs, co-localized with Flt-1. Conditioned media from GCT tissue (GCT-CM) enhanced the chemotaxis and proliferation of OPCs. GCT-CM also stimulated FAK activation in OPCs in vitro. Moreover, there was a correlation between the clinical stage of GCTs and the expression of tyrosine-phosphorylated Flt-1 and FAK.ConclusionsOur results suggest that the VEGF-Flt-1-FAK pathway is involved in the pathogenesis of bone destruction of GCTs.

Minimum 10-year results of cementless total hip arthroplasty in patients with rheumatoid arthritis.

Abstract Objectives: To retrospectively evaluate the long-term results of cementless total hip arthroplasty (THA) in patients with rheumatoid arthritis (RA) and postoperative patient mortality after THA. Methods: This study included 191 hips in 149 RA patients who underwent cementless THA between 1998 and 2005. Mean age at surgery was 54.2 years, and mean follow-up was 12.6 years. Implant and patient survivorships were determined using the Kaplan–Meier method, and the associated influencing factors were determined. Results: Implant survivals at 17 years were 99.5% for stems, 93.9% for cups, and 90.8% for liners. Among the liners used, THAs with highly cross-linked polyethylene showed better survivals compared with those with conventional polyethylene and alumina-bearing surface (93.4%, 90.9%, and 52.2%, respectively). A total of 64 deaths occurred; 45 patients died within 10 years and 19 patients died between 10 and 17 years. Malignancy (25.0%) was the leading cause of death, followed by pneumonia (20.8%) and sepsis (20.8%). The patient survival rate was 36.9% at 17 years after THA. Multivariate analysis exhibited that older age at operation and greater dose of concomitant corticosteroid resulted in shorter patient survivals. Conclusions: Cementless THA worked well in patients with RA. Mortality remained high among RA patients who needed THA.

Arthroplasty for severe deforming arthropathy in overlap syndrome of systemic lupus erythematosus and anti-Jo-1 antibody positive dermatomyositis

Abstract We experienced a rare case of severe contractured and flexed metacarpophalangeal joint (MPJ) arthropathy in a patient with overlap syndrome of systemic lupus erythematosus and dermatomyositis. The patient was a 60-year-old female with high anti-nuclear antibody and anti-Jo-1 antibody titers whose hands had gradually deformed without arthralgia during the past 6 years. Both hands were extremely contractured; in particular, the right hand had dislocations of the second to fifth MPJs, ankyloses of some proximal interphalangeal and distal interphalangeal joints, and z-shaped deformity of the thumb. We performed thumb arthroplasty and artificial joint replacement of the second to fifth MPJs of the dominant right hand. These operations enabled improvement of the patient’s ability to perform daily activities, with an improvement from 1.125 to 0.625 of the Japanese version of the Stanford Health Assessment Questionnaire score. Although surgery to treat contractured deformities can only partially recover the functional ability, it also has indications for arthroplasties.

Mid-term clinical outcome of constrained condylar knee prosthesis for patients with rheumatoid arthritis

Abstract Objectives: This study retrospectively investigated the mid-term outcome of Legacy constrained condylar knee (LCCK) prosthesis in patients with rheumatoid arthritis (RA) having severe varus/valgus deformity, instability, and/or bone loss. Methods: Between January 2000 and December 2015, LCCK prostheses had been performed in 32 knees of 25 patients with RA, and 23 knees of 17 patients of the postoperative follow-up minimum 2 years were analyzed in this study (Primary: 14 knees, Revision: 9 knees). The average of follow-up duration was 6.9 ± 2.7 years, all were female, and the average of age and RA duration at the surgery was 59.0 ± 9.5 years and 26.6 ± 13.5 years, respectively. Clinical result was analyzed by Knee Society Score (KSS) knee and function at preoperative time and final visit. Imaging outcome was investigated by femoral tibial angle (FTA), four component alignment angles, and radiolucent line at pre-/postoperative time. Results: KSS knee/function scores and radiographic FTAs were improved after operation. Radiolucent lines around components were seen in 17 knees (73.9%), of which only one knee (4.3%) has shown aseptic loosening. The seven-year Kaplan-Meier survivorship analysis resulted in 91.7%. Conclusion: LCCK prosthesis in RA patients was achieved to the excellent mid-term clinical and radiographic result.

Reconstruction of Acute Patellar Tendon Rupture after Patellectomy

Acute rupture of the knee extensor mechanism after patellectomy is extremely rare. We present the case of a patient with acute patellar tendon rupture who had undergone patellectomy 53 years before. Twelve days after the injury, the ruptured patellar tendon was repaired with end-to-end suture. Postoperatively, we splinted the knee for 6 weeks but permitted the patient to walk without limiting weight bearing at 1 week postoperatively. At one-year follow-up, the patient is able to move his knee almost full range of motion and the Lysholm knee score is 81. The patient is satisfied with the outcome. This is the first report to treat acute rupture of the patellar tendon in a patient who had undergone patellectomy. Although careful rehabilitation is required, end-to-end suture might be an adequate surgical procedure for acute rupture of the knee extensor mechanism after patellectomy.

Utilizing the Double-door Laminoplasty is Useful to Extirpate Cervical Intradural-extramedullary Tumor

頚椎部の脊髄腫瘍摘出においては，椎弓切除術によるアプローチが多用されてきた．今回我々は，棘突起正中縦割法による脊柱管拡大術を併用し，頚椎硬膜内髄外腫瘍を摘出した1例を経験したので報告する．（症例）63歳女性．平成18年12月より両手の疼痛・しびれが出現し，その後増悪．平成19年1月，近医より頚髄症の疑いで当科紹介．左上肢に知覚低下，両手掌に異常知覚および巧緻運動障害を認めた．MRIにて，C4レベル硬膜内髄外に頭尾径20mmの境界明瞭な，T1低信号，T2高信号，強い造影効果を示す腫瘤を認めた．手術では棘突起正中縦割法にて硬膜を展開し，腫瘍にアプローチした．術後の病理組織診断は，神経鞘腫であった．頚椎部脊髄腫瘍を摘出する際，硬膜管外側までの十分な視野の確保および後方要素を温存することによる支持性の確保という点で，棘突起縦割法の併用は有用と考える．