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BACKGROUND More effective therapies are needed to treat progressive desmoid tumors when active surveillance and systemic therapy fail. OBJECTIVE To assess the efficacy and safety of sandwich isolation surgery on the local control of progressive desmoid tumors involving neurovascular bundles. METHODS A total of 27 patients with progressive desmoid tumors at extremities involving neurovascular bundles who received surgery at our hospital between August 2014 and August 2018 were identified. A total of 13 patients received sandwich isolation surgery, in which R2 resection was performed in neurovasculature-involving regions, and a biomaterial patch was used to envelop involved neurovascular structures and isolate residual tumors. In non-neurovasculature-involving regions, wide resection was performed without isolation. A total of 14 patients received traditional surgery, which included tumor resection without isolation procedure. RESULTS In sandwich isolation group, tumor progressions and local recurrences occurred in 3 patients outside the isolated neurovasculature-involving regions. However, no progressions or recurrences occurred in any patients in the isolated neurovasculature-involving regions where R2 resection was performed. Sandwich isolation surgery group and traditional surgery group shared similar baseline clinical characteristics. The estimated 3-yr event-free survival rate was 76.9% after sandwich isolation surgery, and 32.7% after traditional surgery (P = .025). Patients who received sandwich isolation surgery were less likely to have local recurrence (hazard ratio: 0.257, P = .040). No complications were noted except intermittent mild pain in operative regions (2 cases). CONCLUSION Sandwich isolation surgery is effective and safe for local control of desmoid tumors involving neurovascular bundles.

Osteosarcoma is a type of aggressive malignant bone tumour that frequently metastasizes to lungs, resulting in poor prognosis. However, the molecular mechanisms of lung metastasis of osteosarcoma remain poorly understood. Here we identify exon-intron fusion genes in osteosarcoma cell lines and tissues. These fusion genes are derived from chromosomal translocations that juxtapose the coding region for amino acids 1-38 of Rab22a (Rab22a1-38) with multiple inverted introns and untranslated regions of chromosome 20. The resulting translation products, designated Rab22a-NeoFs, acquire the ability to drive lung metastasis of osteosarcoma. The Rab22a1-38 moiety governs the function of Rab22a-NeoFs by binding to SmgGDS-607, a GTP-GDP exchange factor of RhoA. This association facilitates the release of GTP-bound RhoA from SmgGDS-607, which induces increased activity of RhoA and promotes metastasis. Disrupting the interaction between Rab22a-NeoF1 and SmgGDS-607 with a synthetic peptide prevents lung metastasis in an orthotopic model of osteosarcoma. Our findings may provide a promising strategy for a subset of osteosarcoma patients with lung metastases.

Background Our purpose was to examine the outcomes of patients who underwent extensive resection of periacetabular tumors involving the sacroiliac joint and joint reconstruction with a hemipelvic endoprosthesis. Methods The records of 25 consecutive patients diagnosed with Enneking type I/II/IV pelvic tumors from 2010 to 2016 who received resection and hemipelvic endoprosthesis reconstruction were retrospectively reviewed. Results The median follow-up period was 48 months. At the most recent follow-up, 11 patients were alive, with estimated 3- and 5-year survival rates of 45.6 and 38.0%, respectively. Fourteen patients died, with a mean survival of 20.8 months, and 8 patients had local recurrence at an average of 9.3 months after surgery. Distal metastases were detected in 11 patients at an average of 11.0 months after surgery. The total complication rate was 56.0%, and the most common complications were wound healing disturbances (28.0%) and deep infections (16.0%). The prosthesis-related complication rate was 24.0%; periprosthetic infections and aseptic loosening were most common. The estimated 1- and 3-year prosthesis survival rates were 81.2 and 63.2%, respectively. The mean Musculoskeletal Tumor Society score was 48.0%. Function and prosthesis-related complications did not differ significantly after adding an extra screw fixation to the first sacral vertebra. Conclusions Reconstruction with the hemipelvic endoprosthesis described herein provides satisfactory function with a relatively low complication rate. Adding an extra screw fixation to the first sacral vertebra was not associated with any improvement in the clinical results after short-term follow-up. Improvement and further studies of this endoprosthesis are needed.

Background The rate of postoperative infection developing is higher after limb salvage surgery (LSS) following sarcoma resection compared with conventional arthroplasty. The goal of this study is to summarize our experience in management of periprosthetic joint infection (PJI) and the risk factors of early PJI after LSS. Methods Between January 2010 and July 2019, 53 patients with osteosarcoma in the lower extremities who encountered periprosthetic infection after segmental tumor endoprosthetic replacement in our center were analyzed. Detailed patient characteristics and therapeutic information were collected from database of our institution or follow-up data and we divided patients according to the interval time between infection and tumor resection (surgery-infection interval) and investigate potential risk factors. Results A total of 53 (5.08%) patients were suffered postoperative infection. The average interval between surgery and clinical signs of deep infections are 27.5 days. For the drainage culture, positive results were only presented in 11 patients (20.8%). Almost half of this study’s (47.2%) patients underwent a traditional two-stage revision, that was, after the removal of the infected prosthesis, we applied antibiotic-loaded bone cements as a spacer. The mean blood loss during initial implantation surgery and operation time both correlated with interval period between PJI and initial implantation significantly (P = 0.028, P = 0.046). For several patients which infection marker was hardly back to normal after spacer implantation, we conservatively introduced an improved combination of bone cement and prosthesis for the second-stage surgery (5.6%). There were six patients needing re-operation, of which three were due to the aseptic loosening of the prosthesis, one developed periprosthetic infection again, and two patients encountered local recurrence and underwent amputation. Two patients were dead from distal metastasis. Conclusions A two-stage revision strategy remains effective and standardized methods for PJI patients. Total operation time and blood loss during LSS of osteosarcoma are the main risk factors of early PJI. For the patients without confirmed eradiation of microorganisms, an improved combination of bone cement and prosthesis applied in the second-stage surgery could achieve satisfied functional and oncologic results.

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. Although activator of HSP90 ATPase activity 1 (AHA1) is reported to be a potential oncogene, its role in osteosarcoma progression remains largely unclear. Since metabolism reprogramming is involved in tumorigenesis and cancer metastasis, the relationship between AHA1 and cancer metabolism is unknown. In this study, we found that AHA1 is significantly overexpressed in osteosarcoma and related to the prognosis of osteosarcoma patients. AHA1 promotes the growth and metastasis of osteosarcoma both in vitro and in vivo. Mechanistically, AHA1 upregulates the metabolic activity to meet cellular bioenergetic needs in osteosarcoma. Notably, we identified that isocitrate dehydrogenase 1 (IDH1) is a novel client protein of Hsp90-AHA1. Furthermore, the IDH1 protein level was positively correlated with AHA1 in osteosarcoma. And IDH1 overexpression could partially reverse the effect of AHA1 knockdown on cell growth and migration of osteosarcoma. Moreover, high IDH1 level was also associated with poor prognosis of osteosarcoma patients. This study demonstrates that AHA1 positively regulates IDH1 and metabolic activity to promote osteosarcoma growth and metastasis, which provides novel prognostic biomarkers and promising therapeutic targets for osteosarcoma patients.

The purpose of this study was to evaluate the postrelapse survival of relapsed osteosarcoma with pulmonary metastases in patients who received pulmonary metastasectomy using intent to treat and propensity score analysis.Patients with osteosarcoma who relapsed with pulmonary metastases between 2004 and 2018 who were treated in a hospital affiliated with a medical school were included. All the enrolled patients were evaluated as operable with assessment algorithm at the time of diagnosis of pulmonary relapse and intent to treat analysis was done. Multiple propensity score methods (eg, matching, stratification, covariate adjustment, and inverse probability of treatment weighting) were performed to balance confounding bias. Cox proportional hazards regression and the Kaplan-Meier method were used to evaluate patient survival.A total of 125 patients met the study criteria. Of these, 59 (47.2%) patients received pulmonary metastasectomy combined with chemotherapy and 66 (52.8%) received chemotherapy alone. The 2-year and 5-year postrelapse survival rate of metastasectomy group and nonmetastasectomy group were 68.4% versus 25.0% and 41.0% versus 0%, respectively. The median postrelapse survival was 24.9 versus 13.5 months, respectively. Pulmonary metastasectomy was independently associated with improved survival (hazard ratio, 0.185; 95% confidence interval, 0.103-0.330; P .001). These results were confirmed by multiple propensity score analyses. Further stratified analysis revealed that the survival advantage associated with metastasectomy was not significant in patients with metastases involving ≥3 lung lobes and patients with very high pretreatment serum alkaline phosphatase (more than twice the upper limit).Pulmonary metastasectomy is associated with improved survival in patients with recurrent osteosarcoma.

Background To compare the clinical outcomes of patients with benign or aggressive tumors of the femoral neck who underwent surgical curettage with the use of the direct anterior approach (DAA) and a standard lateral approach. Methods Those patients from 2010 to 2017 were retrospectively enrolled. The patients were divided into two groups: group A, consisting of patients who had undergone surgery via the lateral approach; and group B, consisting of patients who had undergone the same procedure via the DAA. Results Fifty-eight patients were divided into group A (n = 46) and group B (n = 12). The median follow-up was 43 months (15–97 months). There was no significant difference in the 1-year and 3-year recurrence rates (p = 0.74). Group B had comparable operation time and a significantly shorter incision length, less intraoperative blood loss, less postoperative drainage, a shorter hospital stay and less pain on the first postoperative day. Group B also had better hip function as assessed by the Harris Hip Score one month and one year postoperatively. One patient in group B experienced intraoperative incomplete fracture of the femoral neck, which was treated conservatively. Conclusions Surgical curettage for patients with benign or aggressive tumors of the femoral neck via the DAA had a comparable local control rate and a better perioperative and functional outcome than via the lateral approach. Certain quality of the femoral neck should be required to avoid pathological fracture, which is difficult to treat by internal fixation in the DAA.

Background At present, amputation was widely adopted for young patients when limb salvage was deemed risky with several surgical strategy such as rotationplasty. However, leg length discrepancies and unfavorable cosmetic results were indispensable complication of this strategy. The purpose of this study was to propose a novel reconstruction strategy and evaluate the early clinical and functional outcomes of the strategy. Methods Plastic lengthening amputation (PLA) has been developed by lengthening the stump to preserve one additional distal joint for fixing the artificial limb well. The surgical technique and postoperative management were documented, and the functional outcomes were compared with those of traditional amputation (TA). Six pairs of patients matched for age, sex, location, pathological type, and final prosthesis underwent individually designed plastic lengthening amputation with vascularized autografts or traditional amputation between January 2005 and December 2007. All patients were followed, and the locomotor index and the musculoskeletal tumor society score (MSTS) were used to describe and quantitatively grade limb functional outcomes after amputation. The complications and functional outcomes of the patients taken two kinds of procedures were compared. Results Twelve patients with osteosarcoma or Ewing’s sarcoma of either the femur or tibia were included in the study. Six patients underwent plastic lengthening amputations, three of whom also underwent vascular anastomosis. Patients were followed for an average of 48.17 months; bone healing required an average of 3.3 months. No local recurrence was found. The average postoperative locomotor index functional score of the affected limb was 32.67 ± 5.89 in the plastic lengthening amputation group while was 19.50 ± 7.87 in the traditional amputation group. The MSTS functional scores were 22.67 ± 1.33 and 24.17 ± 1.45 at 6 and 12 months for patients in PLA group while 17.00 ± 1.549 and 17.83 ± 1.64 at 6 and 12 months for patients in TA group. Conclusions Plastic lengthening amputations with vascularized autografts could preserve the knee joint to improve the function of the amputated limb in selected bone sarcoma patients.

BackgroundLimb salvage for bone sarcoma around the knee in skeletally immature children is challenging because of interference on two critical growth plates in the lower limb. This retrospective study aims to evaluate long-term outcomes and influence on growth of the lower limb of the cemented extendible endoprostheses.MethodsForty-five children with bone sarcoma around the knee, who underwent custom-made extendible endoprosthesis replacements, were included in this study. The average follow-up was 10.1 years. Survival, prosthetic-related complications and revision, functional outcomes, and influence on growth by prosthesis implantation were recorded.ResultsThe 5-year disease-free survival and overall survival are 54.9% and 72.7%, and the 5-year prosthesis survival rate is 59.4%. The prosthesis was extended 4.2 cm in average. Limb length discrepancies of 20 patients were within 2 cm, and growth inhibition of proximal tibial epiphysis by passive implant insertion was observed. Aseptic loosening in 7 patients was the most significant complication. The Musculoskeletal Tumor Society score at last visit was 83.2%.ConclusionsThe use of custom-made extendible endoprosthesis provided good functional results for children with bone tumor around the knee. Further improvement of the prosthesis design and operation technique will help to decrease complication and gain better limb function.

Osteosarcoma is the most common primary bone tumor in children and adolescents. Many patients with osteosarcoma always develop drug resistance to current chemotherapy regimens, which induces a poor prognosis. And cancer stem cells (CSCs) have been reported to possess the properties to self-renew and maintain the phenotype of tumor, which may lead to clinical treatment failure. Thus, it is an urgent task to develop several potentially useful therapeutic agents, which could target CSCs in osteosarcoma. This study aims to clarify the in vitro and in vivo anti-osteosarcoma effects of dioscin, the primary component derived from Discorea nipponica Makino, and its molecular mechanism of action. In this study, all the ten human osteosarcoma cell lines were sensitive to dioscin treatment in a dose- and time-dependent manner. Dioscin inhibits proliferation and induces cell cycle arrest as well as apoptotic cell death in osteosarcoma cells. More importantly, oral administration of dioscin (60 mg/kg) showed significant therapeutic effect on osteosarcoma growth without obvious side effects in vivo. In addition, dioscin possesses the ability to suppress stem-cell-like phenotype of osteosarcoma cells. Mechanistically, dioscin inhibits osteosarcoma stem-cell-like properties and tumor growth through repression of Akt/GSK3/β-catenin pathway. Moreover, β-catenin expression in osteosarcoma patients was associated with clinical prognosis. Conclusively, the present study provides comprehensive evidence for the inhibition of dioscin on osteosarcoma stem-cell-like properties and tumor growth through repression of Akt/GSK3/β-catenin pathway, which suggests dioscin as a promising therapeutic regimen. And β-catenin may be a potential therapeutic target as well as a significant prognostic marker for osteosarcoma patients in clinic.

Background/Aims: Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. However, the molecular mechanisms regulating osteosarcoma tumorigenesis and progression are still poorly understood. Circular RNAs (circRNAs) have been identified as microRNA sponges and are involved in many important biological processes. This study aims to investigate the global changes in the expression pattern of circRNAs in osteosarcoma and provide a comprehensive understanding of differentially expressed circRNAs. Methods: Microarray based circRNA expression was determined in osteosarcoma cell lines and compared with hFOB1.19, which was used as the normal control. We confirmed the microarray data by real time-qPCR in both osteosarcoma cell lines and tissues. The circRNA/microRNA/mRNA interaction network was predicted using bioinformatics. Gene Ontology analysis and 4 annotation tools for pathway analysis (KEGG, Biocarta, PANTHER and Reactome) were used to predict the functions of differentially expressed circRNAs. Results: We revealed a number of differentially expressed circRNAs and 12 of them were confirmed, which suggests a potential role of circRNAs in OS. Among these differentially expressed circRNAs, hsa_circRNA_103801 was up-regulated in both osteosarcoma cell lines and tissues, while hsa_circRNA_104980 was down-regulated. The most likely potential target miRNAs for hsa_circRNA_103801 include hsa-miR-370-3p, hsa-miR-338-3p and hsa-miR-877-3p, while the most potential target miRNAs of hsa_circRNA_104980 consist of hsa-miR-1298-3p and hsa-miR-660-3p. Functional analysis found that hsa_circRNA_103801 was involved in pathways in cancer, such as the HIF-1, VEGF and angiogenesis pathway, the Rap1 signaling pathway and the PI3K-Akt signaling pathway, while hsa_circRNA_104980 was related to some pathways such as the tight junction pathway. Conclusions: This study has identified the comprehensive expression profile of circRNAs in osteosarcoma for the first time. And the ceRNA network prediction and bioinformatics functional analysis could provide a comprehensive understanding of hsa_circRNA_103801 and hsa_circRNA_104980, which may be involved in the initiation and progression of osteosarcoma. The present study indicates that circRNAs may play important roles in osteosarcoma and thus serve as biomarkers of osteosarcoma diagnosis and treatment.

Purpose: Malignancy of cancer cells depends on the active transcription of tumor-associated genes. Recently, unique clusters of transcriptional enhancers, termed super-enhancers, have been reported to drive the expression of genes that define cell identity. In this study, we characterized specific super-enhancer–associated genes of osteosarcoma, and explored their potential therapeutic value. Experimental Design: Super-enhancer regions were characterized through chromatin immunoprecipitation sequencing (ChIP-seq). RT-qPCR was used to detect the mRNA level of CDK7 in patient specimens and confirm the regulation of sensitive oncogenes by THZ2. The phosphorylation of the initiation-associated sites of RNA polymerase II (RNAPII) C-terminal repeat domain (CTD) was measured using Western blotting. Microarray expression analysis was conducted to explore transcriptional changes after THZ2 treatment. A variety of in vitro and in vivo assays were performed to assess the effects of CDK7 knockdown and THZ2 treatment in osteosarcoma. Results: Super-enhancers were associated with oncogenic transcripts and key genes encoding cell-type–specific transcription factors in osteosarcoma. Knockdown of transcription factor CDK7 reduced phosphorylation of the RNAPII CTD, and suppressed the growth and metastasis of osteosarcoma. A new specific CDK7 inhibitor, THZ2, suppressed cancer biology by inhibition of transcriptional activity. Compared with typical enhancers, osteosarcoma super-enhancer–associated oncogenes were particular vulnerable to this transcriptional disruption. THZ2 exhibited a powerful anti-osteosarcoma effect in vitro and in vivo. Conclusions: Super-enhancer–associated genes contribute to the malignant potential of osteosarcoma, and selectively targeting super-enhancer–associated oncogenes with the specific CDK7 inhibitor THZ2 might be a promising therapeutic strategy for patients with osteosarcoma.

Background The aim of this study was to compare proximal fibular and proximal tibial sites regarding osteosarcoma in the proximal crus. Furthermore, we proposed a hypothesis explaining the differences. Methods From Jaunary 2000 to February 2015, 28 patients with non-metastatic proximal fibular osteosarcoma and 214 patients with non-metastatic proximal tibial osteosarcoma underwent surgery were identified in our center. All clinical data were analyzed retrospectively. Propensity score matching of patients in a 1:2 ratio was conducted based on age, gender and Enneking stage. To analyze possible factors resulting in amputation, we investigated extraosseous tumor volumes (ETVS), the nearest of the blood vessel to reactive zone (NBR) and the nearest of the blood vessel to tumor (NBT). Results Amputation rates were higher in the proximal fibula cohort (35.7%) than in the proximal tibia cohort (14.3%; p = 0.046). Comparing possible clinical characteristics related with amputation between two cohorts, the proximal fibula cohort had larger ETVS (p = 0.000). Moreover, the proximal fibula cohort had a smaller NBT for anterior tibial vessels (p = 0.025), a smaller NBR for posterior tibial vessels (p = 0.013) and a smaller NBT for posterior tibial vessels (p = 0.007) than the proximal tibia cohort. Univarite and multivariable analyses showed that NBT for posterior tibial vessels was the only independent factor associated with amputation. The 3-year event-free survival (EFS) and overall survival (OS) rates for the proximal fibula cohort vs. the proximal tibia cohort were 52.6% vs. 78.0% (p = 0.045) and 63.7% vs. 81.2% (p = 0.177), respectively. The MSTS scores for the functional evaluation of limb-salvaging surgery were similar in both groups (p = 0.212). Conclusions Amputation rates among patients were higher when osteosarcoma was located in proximal fibula than in proximal tibia. A smaller NBT for posterior tibial vessels was associated with higher amputation rates. Prognosis of the proximal fibula cohort was poorer than that of the proximal tibia cohort of osteosarcoma patients. Electronic supplementary material The online version of this article (10.1186/s12885-018-5062-6) contains supplementary material, which is available to authorized users.

Background We aimed to investigate the roles of hemoglobin (Hb) concentrations and dynamic change during treatment on outcomes of patients with extremity osteosarcoma. Methods We retrospectively analysed 133 patients with Enneking stage IIB extremity osteosarcoma who underwent standard treatments, including univariate and multivariate analyses of patient charateritics, Hb concentrations and changes during pretreatment, neoadjuvant, adjuvant chemotherapy, and decreased Hb levels (ΔHb) to assess their prognostic value in 5-year overall survival (OS) and lung metastasis-free survival (LMFS). Results Five-year OS or LMFS were similar between patients who were anaemic and non-anaemic during pretreatment, neoadjuvant or adjuvant chemotherapy. Patients with continuously decreasing Hb had lower 5-year OS (52.3%) than those without continuous Hb decrease (68.5%, P = 0.04). Patients with ΔHb > 7.6 g/L had lower 5-year OS (57.5%) than those with ΔHb ≤7.6 g/L (75.8%, P = 0.04). However, continuous Hb decrease had no prognostic effect on 5-year LMFS. Subgroup analyses showed that patients who were anaemic during pretreatment, neoadjuvant, or adjuvant chemotherapy with ΔHb ≤7.6 g/L had better outcomes than those with ΔHb > 7.6 g/L (P 7.6 predicted poor5-year OS in patients with Enneking stage IIB extremity osteosarcoma. Attempts to correct anaemia and their effects on outcomes for osteosarcoma patients should be investigated in future trials.

// Bo Wang 1, * , Jian Tu 1, * , Junqiang Yin 1 , Changye Zou 1 , Jin Wang 1 , Gang Huang 1 , Xianbiao Xie 1 , Jingnan Shen 1 1 Musculoskeletal Oncology Center, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China * These authors have contributed equally to this work Correspondence to: Xianbiao Xie, e-mail: xiexianbiao@hotmail.com Jingnan Shen, e-mail: shenjn01@hotmail.com Keywords: osteosarcoma, survival outcomes, lung metastases, pretreatment prognostic index Received: May 16, 2015 Accepted: September 18, 2015 Published: October 01, 2015 ABSTRACT Background: To develop a prognostic index to predict the 5-year overall survival (OS) and 5-year lung metastasis-free survival (LMFS) of patients with extremity osteosarcoma at the time of diagnosis. Methods: We retrospectively evaluated 454 patients with extremity osteosarcoma at our center from 2005 to 2013. The cohort was randomly divided into training and validation sets. The association of potential risk factors with OS and LMFS was assessed by Cox proportional hazards analysis in the training set, and a prognostic index was created according to scores that were proportional to a regression coefficient for each factor. This prognostic index was assessed in the validation set. Results: For the 5-year OS, 5 independent prognostic factors were identified: tumor size, Enneking stage, pretreatment platelet, alkaline phosphatase(ALP), and neutrophils. The multivariate Cox model identified tumor size, pretreatment platelets, ALP, and neutrophils as associated with the 5-year LMFS. A prognostic index for death and lung metastases was calculated. Three risk groups were defined for each survival point: low, intermediate, and high risk for the 5-year OS; low, intermediate, and high risk for the 5-year LMFS. The C statistic for the 5-year OS was 0.723 in the training set and 0.710 in the validation set. The C statistic for the 5-year LMFS was 0.661 and 0.693 respectively. Conclusion: This prognostic index is based on routine tests and characteristics of extremity osteosarcoma patients and is a useful predictor of OS and lung metastases. This index could be applied to clinical practice and trials for individualized risk-adapted therapies.

Osteosarcoma is a common malignant bone tumor with a propensity to metastasize to the lungs. Epigenetic abnormalities have been demonstrated to underlie osteosarcoma development; however, the epigenetic mechanisms that are involved in metastasis are not yet clear. Here, we analyzed 2 syngeneic primary human osteosarcoma cell lines that exhibit disparate metastatic potential for differences in epigenetic modifications and expression. Using methylated DNA immunoprecipitation (MeDIP) and microarray expression analysis to screen for metastasis-associated genes, we identified Iroquois homeobox 1 (IRX1). In both human osteosarcoma cell lines and clinical osteosarcoma tissues, IRX1 overexpression was strongly associated with hypomethylation of its own promoter. Furthermore, experimental modulation of IRX1 in osteosarcoma cell lines profoundly altered metastatic activity, including migration, invasion, and resistance to anoikis in vitro, and influenced lung metastasis in murine models. These prometastatic effects of IRX1 were mediated by upregulation of CXCL14/NF-κB signaling. In serum from osteosarcoma patients, the presence of IRX1 hypomethylation in circulating tumor DNA reduced lung metastasis-free survival. Together, these results identify IRX1 as a prometastatic gene, implicate IRX1 hypomethylation as a potential molecular marker for lung metastasis, and suggest that epigenetic reversion of IRX1 activation may be beneficial for controlling osteosarcoma metastasis.

Background Few studies have been done on robot-assisted sacral surgery. This study aims to evaluate the outcomes of seven patients with benign sacral or presacral tumors treated with a robotic surgical system at a single center. Methods All patients with benign sacral or presacral tumors who underwent transperitoneal resection (between June 2015 and June 2016) using the da Vinci Si HD robotic surgical system (Intuitive Surgical Inc.) were included in this retrospective study. Results Seven patients with a mean age of 43.8 years (range: 22- 62 years) were included in this study. The operation time ranged from 60 to 335 min. Five out of these seven patients with presacral tumor underwent complete tumor resection by the da Vinci robotic surgical system, with a median blood loss of 52 ml. The other patients underwent excision of the presacral tumor by the da Vinci robotic surgical system, followed by a posterior approach, with a median blood loss of 675 ml. The histological diagnosis was schwannoma of the sacral nerve in five cases (71.5%). The other two cases were chordoma and solitary fibroma of the sacrum, respectively. No perioperative or postoperative complications were encountered. The average hospitalization stay was 5.7 days. No recurrences were found at follow-up 24 to 31 months later. Conclusion Robot-assisted minimally invasive sacral surgery can provide precise dissection of the tissue under a perfect view. It is a technically feasible procedure that is associated with minimal blood loss, fewer injuries and short hospitalization. It is particularly suitable for presacral benign tumors.

Osteosarcoma is an extremely aggressive primary malignant bone tumor of childhood. Collapsin response mediator proteins (CRMPs), which are highly expressed in the developing nervous system, were recently shown to be associated with cancer development. However, the relationship between DRP5 (CRMP5) and osteosarcoma has not been evaluated. In this study, we investigated the role of DRP5 in the regulation of osteosarcoma growth. DRP5 mRNA and protein levels were significantly upregulated in human osteosarcoma cell lines and associated with increased migration and invasion. Genetic knockdown of DRP5 markedly suppressed the expression of matrix metalloproteinase (MMP)‐2 and MMP‐9. DRP5 silencing significantly inhibited osteosarcoma cell growth in vitro and in a xenograft mouse model in vivo. Microarray immunohistochemical analysis of osteosarcoma specimens and Kaplan–Meier analysis showed that patients with high DRP5 protein expression had shorter overall survival than those with low DRP5 levels. Taken together, these results suggest that DRP5 plays a critical role in the regulation of osteosarcoma and could be a potential therapeutic target and prognostic factor in osteosarcoma.

BACKGROUND: From 30% to 40% patients with osteosarcoma eventually experience medical failure; and few biomarkers of prognostic significance have been established. High-throughput methods like gene microarray analysis can help to identify molecular biomarkers that are useful for diagnosing osteosarcoma and targeting its treatment. METHODS: Oligonucleotide microarrays were used to compare expression profiles of osteosarcoma cell lines and osteoblasts. Differentially expressed genes were confirmed by real-time polymerase chain reaction (PCR) analysis. Corresponding proteins were evaluated by flow cytometry and Western blot analysis in osteosarcoma cell lines and by immunohistochemistry in osteosarcoma tissues. The association between staining intensity and clinical outcome was analyzed further. RESULTS: Cancer-testis antigens, including melanoma antigen family A (MAGEA), chondrosarcoma-associated gene family, member 2 (CSAG2), and preferentially expressed antigen in melanoma (PRAME), were increased significantly in all osteosarcoma cell lines that were analyzed. Real-time PCR examinations indicated that cancer-testis antigen expression was frequent and coordinated in patients with osteosarcoma. The expression of MAGEA was confirmed by Western blot and flow cytometry analyses in osteosarcoma cell lines. Furthermore, immunohistochemical staining analysis suggested that MAGEA expression may be used to predict distant metastasis and poor survival. The adjusted relative risk for lung metastasis was 2.79 (95% confidence interval, 1.12-6.93; P = .028) for MAGEA-positive patients. Five-year survival rates for patients with and without MAGEA expression were 39.6% ± 8.4% and 80% ± 8.9%, respectively (log-rank test; P = .01). CONCLUSIONS: The combined use of an oligonucleotide microarray, a clinical database, and a tissue bank was useful for identifying molecular tumor markers. The frequent expression of MAGEA and other cancer-testis antigens in osteosarcoma indicates that they may be useful as diagnostic markers and targets of immunotherapy that warrant further investigation. Cancer 2012. © 2011 American Cancer Society.

Osteosarcoma is the most common primary malignant bone cancer in children and adolescents. Emerging evidence has suggested that the capability of a tumor to grow is driven by a small subset of cells within a tumor, termed cancer stem cells (CSCs). Although several methods have been explored to identify or enrich CSCs in osteosarcoma, these methods sometimes seem impractical, and chemotherapy enrichment for CSCs in osteosarcoma is rarely investigated. In the present study, we found that short exposure to chemotherapy could change the morphology of osteosarcoma cells and increase sarcosphere formation in vitro, as well as increase tumor formation in vivo. Furthermore, methotrexate (MTX)-resistant U2OS/MTX300 osteosarcoma cells were larger in size and grew much more tightly than parental U2OS cells. More importantly, U2OS/MTX300 cells possessed a higher potential to generate sarcospheres in serum-free conditions compared to parental U2OS cells. Also, U2OS/MTX300 cells exhibited the side population (SP) phenotype and expressed CSC surface markers CD117 and Stro-1. Notably, U2OS/MTX300 cells showed a substantially higher tumorigenicity in nude mice relative to U2OS cells. Therefore, we conclude that chemotherapy enrichment is a feasible and practical way to enrich osteosarcoma stem cells.

To characterize and compare the different biological behaviors of 2 novel human osteosarcoma cell lines, Zos and Zos-M, established respectively from the primary tumor and the skip metastasis of an osteosarcoma patient.In vitro studies included morphological observations, karyotype analysis, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell proliferation assay, and cell sensitivity to chemotherapeutic drugs. Subcutaneous and intravenous inoculations into nude mice were carried out to study the tumorigenicity and the metastatic potential. RT-PCR was performed to assess the expression of the osteoblastic markers and some metastasis-related genes.Both cell lines remained stable for more than 100 passages in vitro without interruption. The RT-PCR examination indicated that they retained the molecular characteristics of an osteoblastic lineage. The karyotype analysis displayed aneuploidy and various structural abnormalities. Both cell lines are tumorigenic; Zos-M differs from Zos by the former's ability to develop lung metastasis after intravenous injection. The comparison of the expression patterns of some metastasis-related genes revealed that the decreased expression of cadherin-11 in Zos-M may correlate with a high potential of metastases. Moreover, both cell lines are less sensitive to the current chemotherapy protocols.The establishment of osteosarcoma cell lines, Zos and Zos-M, and related animal models provide a useful resource for studying the aggressive behavior of osteosarcoma and will be helpful for screening effective treatment strategies.

Aim: To investigate the antiproliferative activity and apoptosis-inducing effects of bufalin on human osteosarcoma cell lines. Methods: U-2OS and U-2OS methotrexate (MTX) 300-resistant cell lines were treated with bufalin. Cell viability was assessed using the MTT assay. Cell-cycle status, apoptosis-inducing effects, and the expression of apoptosis-related proteins were evaluated by flow cytometry, fluorescent staining, DNA fragmentation assays, and Western blotting. The effect of bufalin on dihydrofolate reductase (DHFR) expression was studied by RT-PCR and Western blotting. Results: Bufalin inhibited cell growth in both U-2OS and U-2OS MTX300 cells. The induction of G 2 /M cell-cycle arrest was also seen in the cells treated with bufalin. The induction of apoptosis by bufalin was confirmed by increased expression of the tumor suppressor protein p53 and the increased ratio of the Bax/Bcl-2 proteins. Bufalin induced apoptosis to the same extent in both cell lines without regard to DHFR levels in the cells. Conclusion: Bufalin inhibited the growth of and induced apoptosis in both MTX-sensitive and MTX-resistant human osteosarcoma U-2OS cells. The apoptosis-inducing effect of bufalin was not influenced by the presence of high levels of the DHFR protein.

Purpose To evaluate the effectiveness of reconstruction with a modular hemipelvic endoprosthesis after pelvic tumor resection. Methods We retrospectively studied 50 consecutive patients diagnosed with pelvic tumor from 2003 to 2013. All patients received limb-salvage surgery and reconstruction with modular hemipelvic endoprosthesis. Results Patients were followed for an average of 54 months. At the most recent follow-up, 32 patients were alive with an estimated three-year and five-year survival rate of 66.3% and 57.5% according to the Kaplan-Meier survival analysis. Eighteen patients died from the tumor, with a mean survival of 28 months, and 9 patients experienced local recurrence at an average of 19.6 months after surgery. Patients with marginal or intracapsular surgical margins had a significantly higher recurrence rate than those with wide margins (p=0.02). Metastasis occurred in 12 cases at an average of 16 months after surgery. The perioperative complication rate was 48.0%, and the most common complications were wound healing disturbance (28.0%) and deep infection (14.0%). The endoprosthetic complication rate was 16.0%, and breakage of the pubic connection plate was the most common complication. The mean Musculoskeletal Tumor Society score was 61.4%. Conclusion Reconstruction with a modular hemipelvic endoprosthesis after pelvic tumor resection can improve function, with an acceptable complication rate.

Spinal cord function classification systems are not useful for guiding surgery in patients with severe spinal deformities. The aim of this study is to propose a classification system for determining a surgical strategy that minimizes the risk of neurological dysfunction in patients with severe spinal deformities. The records of 89 patients with severe spinal deformities treated with vertebral column reconstruction from 2008 to 2013 were retrospectively analyzed. Based on neurophysiological monitoring, magnetic resonance imaging, and neurological symptoms patients were categorized into three groups: group A, normal spinal cord, normal evoked potentials and no neurological symptoms; group B, spinal cord abnormalities and/or abnormal evoked potentials but no neurological symptoms; group C, neurological symptoms with or without spinal cord abnormalities/abnormal evoked potentials. Outcomes and complications were compared between the groups. A total of 89 patients (51 male, 38 female) were included with 47 (52.8 %), 16 (18.0 %), and 26 (29.2 %) patients in groups A, B and C, respectively, and a mean follow-up 34.5 months. There were no differences in age, gender, average preoperative scoliosis, and kyphosis among three groups, but there were differences with respect to the causes of severe spinal deformity and the corrective rate of scoliosis and kyphosis. Changes in intraoperative evoked potentials were different in these three types according to this new classification, and the recovery rates of changes in the three groups were 71.1, 50.0, and 14.1 %, respectively. Postoperative spinal cord injury was positively related to intraoperative changes of evoked potentials. The classification system may be useful for guiding surgical decisions in patients with severe spinal deformities to minimize the risk of neurological complications.

To detect the expression of SCUBE3 in human osteosarcoma cell lines and surgical specimens of osteosarcomas and investigate its association with the patients' prognosis.The expression of SCUBE3 protein was detected in 5 osteosarcoma cell lines using Western blotting. CCK8 assay was used to assess the effect of SCUBE3 suppression mediated by two specific small interfering RNAs (siRNAs) on the proliferation of U2OS osteosarcoma cells, and the cell cycle changes were detected using flow cytometry. Immunohistochemistry was performed to detect the expression of SCUBE3 in 60 osteosarcoma tissues, and Kaplan-Meier method was performed for survival analysis of the patients.Compared with osteoblast hFOB1.19 cells, the osteosarcoma cell lines all showed significantly higher expressions of SCUBE3. In U2OS cells, suppression of SCUBE3 expression by siRNA significantly inhibited the cell proliferation (P0.05). Kaplan-Meier survival analysis indicated that patients with high SCUBE3 expression had worse prognosis than those with low SCUBE3 expression (P=0.036).SCUBE3 is up-regulated in the 5 osteosarcoma cell lines and in primary osteosarcoma tissues to promote the proliferation of osteosarcoma cells. A high SCUBE3 expression in osteosarcoma tissues is associated with a poor prognosis of the patients, suggesting that SCUBE3 can serve as a potential therapeutic target for osteosarcoma.

To detect the expression of CXCL14 in human osteosarcoma cell lines and tissues and investigate its association with the prognosis of the patients.RT-PCR, enzyme-linked immunosorbent assay (ELISA) and real-time PCR were used to detect the expression of CXCL14 in 4 osteosarcoma cell lines and in 40 pairs of osteosarcoma tissues and adjacent muscular tissues. CCK8 assay and colony formation assay was used to assess the effect of CXCL14 suppression mediated by two specific siRNAs on the proliferation of U2OS osteosarcoma cells. Immunohistochemistry was performed to detect the expression of CXCL14 in 58 osteosarcoma tissues, and Kaplan-Meier method and log-rank test were performed for survival analysis of the patients.Significant up-regulation of CXCL14 expression was found in the osteosarcoma cell lines and in osteosarcoma tissues compared with the adjacent muscles (P0.01). In U2OS cell, suppression of CXCL14 expression by siRNA significantly inhibited the cell proliferation (P0.01) and colony formation rate (P0.05). Kaplan-Meier survival analysis indicated that patients with high CXCL14 expression had worse prognosis than those with low CXCL14 expression (P=0.02).CXCL14 is up-regulated in both osteosarcoma cell lines and primary osteosarcoma tissues to promote the proliferation of osteosarcoma cells. A high CXCL14 expression in osteosarcoma tissues is associated with a poor prognosis, suggesting the that CXCL14 serve as a potential therapeutic target for osteosarcoma.

Monocarboxylate transporter isoform 1 (MCT1) is an important member of the proton-linked MCT family and has been reported in an array of human cancer cell lines and primary human tumors. MCT1 expression is associated with developing a new therapeutic approach for cancer. In this study, we initially showed that MCT1 is expressed in a variety of human osteosarcoma cell lines. Moreover, we evaluated the therapeutic response of targeting MCT1 using shRNA or MCT1 inhibitor. Inhibiting MCT1 delayed tumor growth in vitro and in vivo, including in an orthotopic model of osteosarcoma. Targeting MCT1 greatly enhanced the sensitivity of human osteosarcoma cells to the chemotherapeutic drugs adriamycin (ADM). In addition, we observed that MCT1 knockdown significantly suppressed the metastatic activity of osteosarcoma, including wound healing, invasion and migration. Further mechanistic studies revealed that the antitumor effects of targeting MCT1 might be related to the NF-κB pathway. Immunochemistry assay showed that MCT1 was an independent positive prognostic marker in osteosarcoma patients. In conclusion, our data, for the first time, demonstrate that MCT1 inhibition has antitumor potential which is associated with the NF-κB pathway, and high MCT1 expression predicates poor overall survival in patients with osteosarcoma.

BackgroundWe sought to determine whether suboptimal chemotherapy compromised the prognosis of osteosarcoma patients.MethodsA total of 132 eligible patients who underwent chemotherapy between 1998 and 2008 were identified in our database. Information regarding patient demographics, clinical characteristics, and survival status were extracted for analysis. Optimal chemotherapy was defined as receipt of ≥80% of the planned dose intensity of prescribed agents within the planned durations.ResultsThe use of optimal chemotherapy resulted in an overall survival benefit withP =0.006. Patients who failed to complete the optimal chemotherapy protocol had a dismal prognosis of 30.8% overall survival over five years, whereas those who completed the optimal chemotherapy had an overall survival rate over five years of 65.3%. Based on multivariate analysis, patients who were treated with a suboptimal protocol had a higher risk of relapse, metastasis and mortality. The hazard ratio (HR) of recurrence or death for the suboptimal chemotherapy group was as high as 2.512 over that of the optimal chemotherapy group (HR = 2.512, 95% confidence interval = 1.242 to 3.729).ConclusionsChemotherapy is a significant independent prognostic variable, and suboptimal chemotherapy was found to have a detrimental effect on the outcome of patients with osteosarcoma.

Cinobufagin, a major component of cinobufacini (huachansu), is an important cardenolidal steroid. Several studies have suggested that cinobufagin has potent anti-cancer effects. The present study examines the apoptosis-inducing activity and the underlying mechanism of action of cinobufagin in osteosarcoma (OS) cells. Our results showed that cinobufagin potently inhibited the proliferation of U2OS, MG63 and SaOS-2 cells. Significant increases in G2/M cell-cycle arrest and apoptosis in OS cells were also observed. The expression levels of several apoptotic proteins were assessed after cinobufagin treatment in U2OS cells. Among them, xIAP, cIAP-1, survivin and Bcl-2 levels decreased remarkably, while the levels of Bax and cleaved-PARP increased. Furthermore, we validated the inhibition of GSK-3β/NF-κB signaling following cinobufagin treatment. Western blots showed a decrease in nuclear p65 protein expression after exposure to different concentrations of cinobufagin, while the phosphorylation of GSK-3β was simultaneously increased. Transduction with constitutively active forms of GSK-3β could protect against the downregulation of p65 and upregulation of cleaved-PARP that are induced by cinobufagin treatment. However, combined treatment with cinobufagin and SB216367 resulted in a significant reduction in p65 and an increase in cleaved-PARP in U2OS cells. Altogether, these results show that cinobufagin is a promising agent for the treatment of OS. These studies are the first to reveal the involvement of the GSK-3β/NF-κB pathway in cinobufagin-induced apoptosis.

Objective To study the effect and mechanisms of quercetin (Qu) on proliferation and apoptosis of human methotrexate resistant osteosarcoma cell U-2OS/MTX300. Method MTT assay was used to observe cell proliferation. The apoptosis was examined by using Annexin V/PI staining. Western blot of mitochondrial membrane potential and cytochrome c were used to detect mitochondria spoptosis pathway. The protein expressions related to Akt pathway was detected by continuous activated Akt transient transfection and western blot. Result Qu can obviously inhibit the growth of human MTX resistant osteosarcoma cell U-2OS/MTX300 cells in a dose- and time-dependent manner. Annexin V/PI staining showed obvious cell apoptosis. Reduction of mitochondrial membrane potential, release of mitochondrial cytochrome c to cytosol and dephoshorylation of Akt were observed after Qu treatment. Conclusion Qu can inhibit proliferation and induce apoptosis of human MTX resistant osteosarcoma cell U-2OS/MTX300, which may be related with mitochondrial apoptosis pathway and Akt activity.

The preferentially expressed antigen of melanoma (PRAME), a cancer-testis antigen with unknown function, is expressed in many human malignancies and is considered an attractive potential target for tumor immunotherapy. However, studies of its expression and function in osteosarcoma have rarely been reported. In this study, we found that PRAME is expressed in five osteosarcoma cell lines and in more than 70% of osteosarcoma patient specimens. In addition, an immunohistochemical analysis showed that high PRAME expression was associated with poor prognosis and lung metastasis. Furthermore, PRAME siRNA knockdown significantly suppressed the proliferation, colony formation, and G1 cell cycle arrest in U-2OS cells. Our results suggest that PRAME plays an important role in cell proliferation and disease progression in osteosarcoma. However, the detail mechanisms of PRAME function in osteosarcoma require further investigation.

To evaluate the effectiveness of prosthetic revision using custom-made long stem prosthesis and allograft-prosthesis composite (APC) for aseptic loosening after bone tumor resection.Between January 2002 and June 2008, 14 patients with aseptic loosening after bone tumor resection were treated. There were 8 males and 6 females, aged 21-70 years (mean, 43.9 years). The locations were distal femur (8 cases), proximal femur (2 cases), and proximal tibia (4 cases). Pain of the affected limb occurred after 6-31 years of prosthesis replacement and worsened when bearing and walking; 6 patients had shortened limb. The functional results were assessed quantitatively according to the functional rating system of the Musculoskeletal Tumor Society (MSTS). The MSTS score was 16.36 +/- 1.50 before revision. The X-ray films showed obvious prosthetic loosening and subsidence. The average time of symptom was 4.5 years (range, 3-9 years). In 7 patients having severe bone loss (the decrease of the thickness of cortical bone was more than 50%) and the prosthetic subsidence was more than 2 cm, the revision operation with the APC was performed; in 7 patients having less bone loss (the decrease of the thickness of cortical bone was less than 50%), the custom-made long stem prosthesis was performed.All wound healed by first intention. Two patients had temporary peroneal nerve paralysis and recovered after 3 months. All the patients were followed up 3.6 years on average (range, 2 years and 2 months- 7 years) after revision. After revision, pain was relieved and the range of joint was improved. The MSTS score was 23.43 +/- 2.56 at 12 months after revision showing significant difference when compared with the preoperative score (t = 8.910, P = 0.024). The X-ray films showed that lucency space line around stem cement in 2 patients at 12 months, and no prosthesis loosening and infection occurred.The prosthetic revision after limb salvage surgery with prosthesis for bone tumors was acceptable. The good functional results can be achieved by the revision with the APC or the custom-made long stem prosthesis according to the bone loss.

Aim Limb-salvage surgery has become the standard of care for extremity osteosarcoma. In this study, we investigated the survival and functional outcomes of patients with osteosarcoma around the knee who were treated with limb-salvage surgery. Methods We retrospectively reviewed the clinical data for 120 patients with osteosarcoma around the knee who were treated with limb-salvage surgery between 1998 and 2008. The sample included 75 males and 45 females. The mean age of the patients was 18.9 years. Osteosarcoma was diagnosed in the distal femur in 78 patients and in the proximal tibia in 42 patients. Statistical analyses were conducted to process and record the patient data and analyse the surgery's efficacy, prognosis and survival rates. Results All patients were followed for 6–144 months (mean of 56.8 months). The overall 5-year survival rate was 61.8%. Lung metastasis developed in 31 patients. Local recurrence developed in 9 patients. The average Musculoskeletal Tumor Society Score (MSTS) was 25.5 points on a 30-point scale. Sixteen patients underwent prosthesis revision and twelve patients underwent amputation. The overall survivorship of the prosthesis based on Kaplan–Meier estimates was 77% at five years and 71% at ten years. There was a higher incidence of extensor lag for the patients with osteosarcoma in the proximal tibia than for those with osteosarcoma in the distal femur ( P Conclusions Treating osteosarcoma around the knee with limb-salvage surgery can preserve most of the knee's functionality. Attention must be paid to prevent the relatively high incidence of postoperative complications.

Iliosacral resection of pelvic malignant tumors and subsequent reconstruction have tested the ingenuity of orthopedic oncologists because of the difficulty of oncological wide resection and the complex biomechanics of the sacroiliac joint render reconstruction challenging. This study compared the functional and surgical outcomes of a biological reconstruction technique with the lack of reconstruction following iliosacral resection.Twenty-six consecutive cases with malignant iliac tumors involving the sacrum were retrospectively reviewed. These cases underwent iliosacral resection (type I/IV) followed by no reconstruction or a biological reconstruction blinded to authors between 1997 and 2007. After iliosacral resection, 12 cases underwent reconstruction with nonvascular fibular grafts and plate and/or pedicle screw-rod; the other 14 cases did not undergo reconstruction.The median follow-up was 84.42 (range, 32-165) months. The local recurrence rate in the reconstruction group was 8.33 % (1/12) with 14.29 % (2/14) in the group without reconstruction. The functional score of the biological reconstruction group was significantly higher than that of the no-reconstruction group as determined by Student's t test. In the biological reconstruction group, bone fusion occurred in 91 % of cases and fibula hypertrophy was observed in 41.7 %. Complications included sciatic nerve palsy, broken screws, intractable pain, nonunion, pelvic oblique, and leg-length discrepancy.After iliosacral resections of pelvic malignant tumors, the biologic reconstruction of these defects could restore spinopelvic stability and continuity. The double-barrel fibular autograft combined with the plate or pedicle screw-rod system is an effective reconstruction method for both optimal short- and long-term stability.

Quercetin is the most abundant polyphenolic flavonoid found in plants. Several studies suggest that it has potent anticancer effects. The present study examines the apoptosis-inducing activity and the underlying mechanism of action of quercetin in a methotrexate (MTX)-resistant osteosarcoma model. Our results showed that quercetin inhibited cell viability in a dose-dependent manner and there was no cross-resistance between MTX and quercetin in U2-OS/MTX300 cells. The induction of apoptosis was observed by flow cyto-metry and fluorescence staining experiments. Quercetin-induced apoptosis was accompanied by a significant reduction of mitochondrial membrane potential, release of mitochondrial cytochrome c to the cytosol, activation of caspase-3, down-regulation of Bcl-2, p-Bad and up-regulation of Bax. A remarkable dephospho-rylation of Akt was also detected after quercetin treatment. Furthermore, transduction with constitutively active Akt protected against the quercetin-induced dephosphorylation of Akt and Bad as well as poly(ADP-ribose)polymerase (PARP) degradation, while combined treatment with quercetin and LY294002 enhanced the dephosphorylation of Akt, Bad and PARP cleavage in U2-OS/MTX300 cells. Taken together, our results demonstrate that quercetin-induced apoptosis in the MTX-resistant osteosarcoma cells U2-OS/MTX300 was mediated via mitochondrial dysfunction and dephosphorylation of Akt.

Ezrin, a membrane organizer and linker between plasma membrane and cytoskeleton, is well documented to play an important role in the metastatic capacity of cancer cells especially for osteosarcoma cells. It has provided an ideal target for cancer gene therapy. RNA-cleaving 10-23 DNAzymes, consisting of a 15-nucleotide catalytical domain flanked by two target-specific complementary arms, can cleave the target mRNA at purine-pyrimidine dinucleotide effectively. In the present study, we designed and screened the target sites for 10-23 DNAzymes against ezrin mRNA by using multiple computational methods with combination of secondary structural and hybridization thermodynamic parameters. Then, we testified the activities of the DNAzymes directed against these selected target sites in vitro. Our results show that AU1751 is the most effective target site of ezrin mRNA for DNAzymes because of its ideal secondary structure and hybridization thermodynamics. So, there is a significant correlation between the multiple computational methods and the efficacy of the corresponding DNAzymes. These provide a rational, efficient way for DNAzymes selection.

Background and objectives Due to possible complication and loss of function, surgery is not often indicated in pelvic Ewing's sarcoma (ES). The purpose of this study was to review our experience and evaluate the role of different local treatment in non-metastatic pelvic ES patients. Methods One hundred twenty-nine patients with pelvic ES were treated at our institution between 1975 and 1999. We excluded patients presenting metastases, patients who had died of other causes, or those with incomplete clinical documentation. Among the 73 eligible patients, 17 (23%) with progression of tumor growth during induction chemotherapy eventually died. The analysis was focused on the remaining 56 patients with good or stable clinical response to the chemotherapy. Results Patients treated with surgery, with or without radiation therapy, had a better local control (82.6% vs. 66.7%) and a significantly higher rate of 5-year EFS (73.9% vs. 30.3%, P = 0.036) than those who were only treated with local radiation therapy. Conclusion Chemotherapy is the key factor in the treatment of pelvic ES. In our series, surgical treatment was associated with good prognosis for pelvic ES. The use of radiotherapy alone was less effective and should be only used in non-operable patients. Radiotherapy after surgery as a rescue method might not act effectively, while preoperative radiotherapy was associated with good clinical response and should be recommended. J. Surg. Oncol. 2007;96:19–25. © 2007 Wiley-Liss, Inc.