Jung Ryul Kim

Tumor infiltrating PD1-positive lymphocytes and the expression of PD-L1 predict poor prognosis of soft tissue sarcomas.

Recently, the possibility of PD1 pathway-targeted therapy has been extensively studied in various human malignant tumors. However, no previous study has investigated their potential application for soft-tissue sarcomas (STS). In this study, we evaluated the clinical impact of intra-tumoral infiltration of PD1-positive lymphocytes and PD-L1 expression in tumor cells in 105 cases of STS. Intra-tumoral infiltration of PD1-positive lymphocytes and PD-L1 expression were seen in 65% and 58% of STS, respectively. Both PD1-positivity and PD-L1 expression were significantly associated with advanced clinicopathological parameters such as higher clinical stage, presence of distant metastasis, higher histological grade, poor differentiation of tumor, and tumor necrosis. Moreover, both PD1-positivity and PD-L1 positivity were independent prognostic indicators of overall survival (OS) and event-free survival (EFS) of STS by multivariate analysis. In addition, the combined pattern of PD1- and PD-L1-positivity was also an independent prognostic indicator for OS and EFS by multivariate analysis. The patents with a PD1+/PD-L1+ pattern had the shortest survival time. In conclusion, this study is the first to demonstrate that the infiltration of PD1 positive lymphocytes and PD-L1 expression in STS cells could be used as novel prognostic indicators for STS. Moreover, the evaluation of PD1- and PD-L1-positivity in STS is also available as possible criteria for selection of patients suitable for PD1-based immunotherapy.

Expression of SIRT1 and DBC1 Is Associated with Poor Prognosis of Soft Tissue Sarcomas

Recently, the roles of SIRT1 and deleted in breast cancer 1 (DBC1) in human cancer have been extensively studied and it has been demonstrated that they are involved in many human carcinomas. However, their clinical significance for soft-tissue sarcomas has not been examined. In this study, we evaluated the expression and prognostic significance of the expression of SIRT1, DBC1, P53, β-catenin, cyclin D1, and KI67 in 104 cases of soft-tissue sarcomas. RESULTS: Immunohistochemical expression of SIRT1, DBC1, P53, β-catenin, and cyclin D1 were seen in 71%, 74%, 53%, 48%, and 73% of sarcomas, respectively. The expression of SIRT1, DBC1, P53, β-catenin, and cyclin D1 were significantly correlated with advanced clinicopathological parameters such as higher clinical stage, higher histological grade, increased mitotic counts, and distant metastasis. The expression of SIRT1, DBC1, P53, β-catenin, cyclin D1, and KI67 were significantly correlated with each other and positive expression of all of these predicted shorter overall survival and event-free survival by univariate analysis. Multivariate analysis revealed the expression of SIRT1 as an independent prognostic indicator for overall survival and event-free survival of sarcoma patients. In conclusion, this study demonstrates that SIRT1- and DBC1-related pathways may be involved in the progression of soft-tissue sarcomas and can be used as clinically significant prognostic indicators for sarcoma patients. Moreover, the SIRT1- and DBC1-related pathways could be new therapeutic targets for the treatment of sarcomas.

Nonisthmal femoral shaft nonunion as a risk factor for exchange nailing failure.

Background: Although nail exchange with a larger diameter nail after additional reaming is typically considered the gold standard for failed femoral nailing, some reports question the role of exchange nailing. The purpose of this study was to evaluate the risk factors affecting the outcome of exchange nailing for femoral shaft nonunion after initial nailing. Methods: Forty-one consecutive patients treated with exchange nailing between November 1996 and March 2010 for femoral shaft nonunion that was initially managed with an intramedullary nailing were retrospectively reviewed. Possible risk factors and outcome (bony union) of exchange nailing were evaluated. Results: Of the 41 femoral shaft nonunions treated with exchange nailing, 9 (22%) failed to achieve bony union. The union rate for isthmal nonunions was 87% (27 of 31 cases) and for nonisthmal nonunions was 50% (5 of 10 cases). Univariate and multivariate logistic regression analyses demonstrated that the anatomic site (isthmal vs. nonisthmal) was a significant risk factor for exchange nailing failure (univariate, p = 0.021; multivariate, p = 0.016). Conclusions: Although exchange nailing is an excellent choice for aseptic isthmal femoral shaft nonunion occurring after the initial nailing, other treatment options such as augmentative plating should be considered for nonisthmal femoral shaft nonunions.

Treatment Outcomes of Triplane and Tillaux Fractures of the Ankle in Adolescence

Background To identify the fracture configuration and treatment results for patients with triplane and Tillaux fractures in the ankle joint. Methods A retrospective study was performed on 14 patients with a more than one year follow-up. This study investigated the fracture configuration, concomitant fibula fracture, treatment methods and complications. The treatment outcomes were analyzed using modified Weber protocol. Results Among the 14 cases, 11 were triplane fractures and 3 were Tillaux fractures. Seven were two part triplane fractures, and 4 were three part triplane fractures. Eight were lateral triplane fractures, and 3 were medial triplane fractures. A fibula fracture was accompanied by 7. The fibular fracture comprised of oblique fractures in all cases. A closed and open reduction was performed in 6 and 8 cases, respectively. All but one showed excellent treatment outcomes at the final follow-up. Traumatic arthritis developed in 1 case. Conclusions Precisely detecting the fracture configuration by computed tomography and understanding the injury mechanism have greatly improved the outcomes of triplane fractures and Tillaux fractures of the ankle in adolescent patients.

COMP–angiopoietin-1 accelerates bone formation during distraction osteogenesis

INTRODUCTION During distraction osteogenesis, new and highly vascularized bone is formed, with angiogenesis preceding osteogenesis. We investigated the possibility that COMP-Ang1, an angiogenic factor, may facilitate bone formation. METHODS Rats were divided into three groups. Control rats underwent tibial distraction without treatment. In the two remaining groups, BSA (100 microg) or COMP-Ang1 (100 microg) were injected transcutaneously into the center of the distraction zone. Using radiographic and histologic analyses, we assessed total bone volume, vascular density, and bone mineral density. Total RNA was prepared from regenerated bone and analyzed for osteogenic marker protein expression using real-time RT-PCR analysis. RESULTS Bone formation in the distraction gap progressed more quickly in the COMP-Ang1-treated group than in the BSA-treated group. Histological findings and immunostaining of endothelial cells for factor VIII revealed that Comp-Ang1 group animals exhibited higher levels of vascularity. NanoCT and dual-energy X-ray absorptiometry analyses revealed increased new bone formation along capillaries in the COMP-Ang1 group compared with the BSA group. Runt-related transcription factor 2 and its target genes, including bone sialoprotein, type 1 collagen, osteopontin, and osterix, were significantly upregulated in the COMP-Ang1 group. CONCLUSIONS Our results are consistent with previous descriptions of the positive relationship between angiogenesis and osteogenesis. In addition, our results suggest the potential use of COMP-Ang1 as a therapeutic agent for treatment of distracted limbs by enhancing angiogenesis.

Concurrent bilateral patellar tendon rupture in a preadolescent athlete: a case report and review of the literature

Concurrent bilateral patellar tendon rupture in preadolescence is a very rare condition. It is mostly associated with systemic disease or steroid use in adults. We report a case of 12-year-old boy, who had bilateral patellar tendon rupture, treated with nonabsorbable synthetic suturing with titanium osseous anchors. Moreover, we discuss the causes of patellar tendon rupture, diagnostic clues and surgical options.

Enhancement of tibial regeneration in a rat model by adipose-derived stromal cells in a PLGA scaffold

INTRODUCTION Autologous adipose-derived stromal cells (ASCs) are an obvious source of osteogenic cells and can be easily isolated from adipose tissue. We evaluated the potential of ASCs seeded onto a scaffold to heal tibial defects. METHODS Autologous ASCs were obtained from adipose tissue by collagenase digestion. The cells were seeded in three-dimensional poly(lactic)-glycolic acid (PLGA) scaffolds and cultured in osteogenic medium for four weeks. Evidence of osteogenesis was assessed by von Kossa staining in three-dimensional cultures following osteogenic induction. The critical size tibial defects (10mm) were created using a rat model. Defects were either left empty (sham group), treated with a PLGA scaffold alone (PLGA group), or a PLGA/ASC composite (PLGA/ASC group). Using radiologic and histologic analyses, we assessed total bone volume and vascular density. Total RNA was prepared from regenerated bone and analyzed for osteogenic marker gene expression. RESULTS In three-dimensional cultures, the PLGA/ASC composite showed multiple calcified extracellular matrix nodules on von Kossa staining after four weeks of differentiation. Near complete healing was observed between the PLGA/ASC engrafted tibial defects on plain radiographs and micro-CT findings. Total bone volume and mechanical strength were significantly higher in the PLGA/ASC group compared to the sham and PLGA groups. Histologic analysis revealed increased new bone formation along capillaries in the PLGA/ASC group. Real-time RT-PCR analysis revealed a significant increase in the expression of osteogenic genes in the PLGA/ASC group. CONCLUSIONS The results showed that the repair of tibial defects was accelerated by implantation of autologous ASCs seeded onto a PLGA scaffold. Therefore, PLGA/ASC is a promising new cell-based therapy for healing critical size tibial defects.

Acceleration of spinal fusion using COMP-angiopoietin 1 with allografting in a rat model

INTRODUCTION Allografting has become widely available for the elimination of morbidity due to autogenous bone grafting procedures for spinal fusion. Enhancement of stable bone formation could facilitate this procedure. COMP-Ang1 is a recombinant chimeric protein of angiopoietin-1 that induces angiogenesis and vascular enlargement. We investigated the osteogenic potential of COMP-Ang1 for spinal fusion with allograft based on the enhancement of angiogenesis. METHODS Sixty Sprague-Dawley rats underwent bilateral posterior and posterolateral arthrodesis with allograft at L3-4 and L4-5. The animals were divided into three groups (n=20 each): (1) no treatment (sham group); (2) the bovine serum albumin-impregnated collagen sponge group (BSA group); 3) the COMP-Ang1-impregnated collagen sponge group (COMP-Ang1 group). Animals were sacrificed at six weeks for evaluation of spinal fusion using manual palpation, radiographs, and biomechanical and histomorphometric assessments. Total RNA was prepared from the fusion site and analyzed for osteogenic marker protein expression using RT-PCR analysis. RESULTS The fusion rates determined by manual palpation were 38.9% in the sham group, 42.1% in the BSA group, and 89.5% in the COMP-Ang1 group. Optical density of fusion masses in the COMP-Ang1 group was significantly higher than those in the sham and BSA groups (p<0.001). Total bone volume was significantly higher in the COMP-Ang1 group than in the sham and BSA groups (p<0.001). The mechanical strength was significantly greater in the COMP-Ang1 group than in the sham and BSA groups (p<0.01). Histologically, the fusion site of the COMP-Ang1 group showed a larger number of reactive bones compared with those in the BSA and sham groups. Immunostaining of endothelial cells for factor VIII revealed that COMP-Ang1 group showed higher levels of vascularity in the fusion site. Runt-related transcription factor 2 and its target genes were significantly up-regulated in the COMP-Ang1 group. CONCLUSIONS COMP-Ang1 induced radiologically and histologically demonstrable active osteogenesis by promoting angiogenesis in spinal fusions. It was concluded that COMP-Ang1 enhances spinal fusion and hence the strength of the fusion.

The overexpression of BAMBI and its involvement in the growth and invasion of human osteosarcoma cells

The pseudoreceptor BAMBI (bone morphogenetic protein and activin membrane-bound inhibitor), formerly known as NMA, is an inhibitor of the TGF-β signaling pathway. BAMBI exhibits structural homology to TGF-βRI but lacks an intracellular kinase domain. In most of the high-grade carcinomas, the degree of BAMBI expression is abnormally increased, which leads to the proliferation and metastasis of tumor cells. Recent studies have reported that BAMBI is involved in the Wnt-β-catenin pathway that regulates the proliferation and metastasis of tumor cells. However, little is known about the role of BAMBI and β-catenin in human osteosarcoma. Given the above background, we examined the role of BAMBI in the pathophysiology of osteosarcoma. Using immunohistochemical staining and western blot analysis, the degree of the expression of BAMBI and β-catenin was significantly higher in osteosarcoma specimens compared with normal tissues. With the overexpression of BAMBI, mediated by adenovirus, the degree of invasion and migration was significantly increased and the proliferation of U2-OS osteosarcoma cells was stimulated. Transwell analysis showed that BAMBI increased the invasion of osteosarcoma cells and upregulated the secretion of matrix metalloproteinases (MMPs), which was demonstrated by gelatin zymography. Fluorescence-activated cell sorting (FACS) analysis showed a significant arrest in cell cycle progression at G0/G1 in osteosarcoma cells transfected with siRNA targeting BAMBI. With the overexpression of BAMBI, mediated by the adenovirus, however, there was a decrease in the number of cells at G0/G1. Consistent with the findings that cell growth was increased, BAMBI promoted the transition from G0/G1 to G2/M in the osteosarcoma cells. Our results suggest that BAMBI plays a key role in the pathogenesis and progression of osteosarcoma by regulating the expression of β-catenin and other signaling molecules via the pathways involved in the regulation of the cell cycle. This relationship between BAMBI and its involvement in the regulation of the cell cycle would provide a possibility that the BAMBI may be a new target for gene therapy.

Induction of G2/M arrest and apoptosis by sulforaphane in human osteosarcoma U2-OS cells

Sulforaphane is one of the most abundant isothiocyanates found in certain cruciferous vegetables, particularly broccoli. To date, sulforaphane has gained attention as a chemopreventive compound. The mechanism responsible for the anticancer effects of sulforaphane in osteosarcoma, however, is not clear. In this study, we demonstrate an anti-proliferative mechanism of sulforaphane in human osteosarcoma cells. The treatment of cells with sulforaphane resulted in a concentration- and time‑dependent inhibition of growth and G2/M phase arrest of the cell cycle. This effect was associated with a decrease in protein expression of cyclin A and B1 and their activating partners, cyclin-dependent kinases (CDKs) 1 and 2, with concomitant up-regulation of p21, a CDK inhibitor. Sulforaphane treatment also resulted in apoptosis as evidenced by an increase in annexin V+/propidium iodide- (V+/PI-) cells, the cleavage of 116-kDa poly (ADP-ribose) polymerase (PARP) and ICAD and oligonucleosomal DNA fragmentation. Taken together, these findings indicate that the molecular mechanisms underlying sulforaphane-mediated growth inhibition in U2-OS cells may be the modulation of the cell cycle machinery and the induction of apoptosis.