Prognostic markers in osteosarcoma

An immune-related eleven-RNA signature-drived risk score model for prognosis of osteosarcoma metastasis

This study aimed to determine an immune-related RNA signature as a prognostic marker, in this study, we developed a risk score model for predicting the prognosis of osteosarcoma metastasis. We first downloaded the clinical information and expression data of osteosarcoma samples from the UCSC Xena and GEO databases, of which the former was the training set and the latter was the validation set. Immune infiltration was assessed using the ssGSEA and ESTIMATE algorithms, and the osteosarcoma samples were divided into the Immunity_L and Immunity_H groups. Then, eleven RNAs were identified as the optimal prognostic RNA signatures using LASSO Cox regression analysis for establishing a risk score (RS) model. Kaplan-Meier approach indicated the high-risk group exhibited a shorter survival. Furthermore, we analyzed the tumor metastasis, age, and RS model status were determined to be independent clinical prognostic factors using Cox regression analysis. Decision curve analysis (DCA) indicated that the prognostic factor + RS model had the best net benefit. Finally, nine tumor-infiltrating immune cells (TIICs) showed significant differences in abundance between high- and low-risk groups via CIBERSORT deconvolution algorithm. In conclusion, the immune-related eleven-RNA signature be could served as a potential prognostic biomarker for osteosarcoma metastasis.

Animal Models and Their Role in Imaging-Assisted Co-Clinical Trials

The availability of high-fidelity animal models for oncology research has grown enormously in recent years, enabling preclinical studies relevant to prevention, diagnosis, and treatment of cancer to be undertaken. This has led to increased opportunities to conduct co-clinical trials, which are studies on patients that are carried out parallel to or sequentially with animal models of cancer that mirror the biology of the patients' tumors. Patient-derived xenografts (PDX) and genetically engineered mouse models (GEMM) are considered to be the models that best represent human disease and have high translational value. Notably, one element of co-clinical trials that still needs significant optimization is quantitative imaging. The National Cancer Institute has organized a Co-Clinical Imaging Resource Program (CIRP) network to establish best practices for co-clinical imaging and to optimize translational quantitative imaging methodologies. This overview describes the ten co-clinical trials of investigators from eleven institutions who are currently supported by the CIRP initiative and are members of the Animal Models and Co-clinical Trials (AMCT) Working Group. Each team describes their corresponding clinical trial, type of cancer targeted, rationale for choice of animal models, therapy, and imaging modalities. The strengths and weaknesses of the co-clinical trial design and the challenges encountered are considered. The rich research resources generated by the members of the AMCT Working Group will benefit the broad research community and improve the quality and translational impact of imaging in co-clinical trials.

Polypeptide N-Acetylgalactosaminyltransferase 14 (GALNT14) as a Chemosensitivity-Related Biomarker for Osteosarcoma

Purpose

Osteosarcoma is the most common primary bone tumor. Polypeptide N-acetylgalactosaminyltransferase 14 (GALNT14), a member of the N-acetylgalactosaminyltransferase family, has been considered to be associated with various cancers. However, its role in osteosarcoma remains unknown. Here, we aimed to explore the expression and potential mechanism of GALNT14 in osteosarcoma through bioinformatics analysis and in vitro experiments.

Methods

We investigated GALNT14 expression in osteosarcoma using GEO, the TIMER database, and clinical samples. Protein-protein interaction (PPI) network analysis on GALNT14 was performed by STRING. TARGET was used to identify differentially expressed genes (DEGs) between high and low GALNT14 expression. The correlation between GALNT14 and cuproptosis-related genes in osteosarcoma was analyzed by R language. The prognostic significance of GALNT14 was examined by Kaplan-Meier survival analysis. Additionally, we inhibited GALNT14 function in an osteosarcoma cell line by transfecting siRNA and subsequently explored the effect on drug sensitivity by CCK-8, clonogenic assay, and flow cytometry.

Results

GALNT14 was significantly elevated in osteosarcoma tissue, osteosarcoma cell lines, and metastatic osteosarcoma. PPI analysis revealed that GALNT14 was associated with MUC7, MUC13, MUC5AC, C1GALT1, MUC15, MUC16, MUC1, MUC4, MUC21, and MUC17. In the high GALNT14 expression group, we discovered 81 upregulated DEGs and 73 downregulated DEGs. Functional enrichment analysis of DEGs showed significant enrichment in the Wnt, TGF-β, Hippo, PI3K signaling pathways and cell adhesion molecules. Expression of cuproptosis-related genes was closely related in osteosarcoma, and GALNT14 expression was significantly positively correlated with FDX1, a key regulator of cuproptosis. Kaplan-Meier survival showed that GALNT14 was linked to poor overall survival and disease-free survival in osteosarcoma. In vitro experiments suggested that GALNT14 was associated with chemotherapy resistance in osteosarcoma.

Conclusion

We identified a GALNT family gene, GALNT14, that was highly expressed in osteosarcoma. This gene was closely associated with metastasis, progression, cuproptosis-related genes, and chemosensitivity of osteosarcoma, and showed correlation with poor overall survival and disease-free survival in osteosarcoma.

Controversies and Challenges in the Management of Osteosarcoma-an Indian Perspective

Osteosarcoma (OGS) is the most common primary bone tumor in children and adolescents which requires a multidisciplinary approach to management. Although chemotherapy and surgery can cure more than half of localized OGS cases, the unique challenges faced by resource-limited countries like India make this outcome difficult to achieve. Various questions in the management of OGS including role of high-dose methotrexate (HDMTX) in neoadjuvant setting, triplet vs doublet chemotherapy, intensification of chemotherapy based on response in setting of doublet, and indigenous prosthesis in setting of limb salvage need to be defined. Similarly, in the metastatic and recurrent setting, questions regarding intent of treatment, indications of chemotherapy, timing of surgery, and role of targeted therapies need clarification. Lack of randomized trials from India makes definite conclusions difficult, but an attempt can be made to define the best approach in the Indian scenario from available evidence. Hence, a critical review of literature from India and the West was done to define possible management approaches and highlight the lacuna for future research.

Resource-appropriate selection of osteosarcoma treatment protocols in low- and middle-income countries

Osteosarcoma is a rare malignancy; however, it is still the most common primary bone tumor in adolescents and young adults. Chemotherapy improves survival indubitably in osteosarcoma; nevertheless, the concern is the stagnant progress since the last several decades. There are a handful of active agents and unresolved issues, especially in choosing the ideal chemotherapy regimen. The oncology community is in equipoise regarding the position of high-dose methotrexate (HDMTX), mandatory or adjunct. The choice of therapy becomes widely relevant, including in low- and middle-income countries (LMIC), where HDMTX administration brings additional complexities. Research into novel non-HDMTX-based protocols adapted to the available resources is pivotal in improving disease outcomes, especially in LMIC. The current review focuses on real-world challenges in decision-making and provides a comprehensive overview of the evolution of treatment protocols in LMIC.

Curcumin inhibits the proliferation and invasion of MG-63 cells through inactivation of the p-JAK2/p-STAT3 pathway

Purpose

The aims of this study were to determine the effect of curcumin on osteosarcoma (OS) cells due to inactivation of the p-JAK2/p-STAT3 pathway and evaluate the prognostic value of this pathway in OS.

Materials and methods

We exposed a human OS cell line (MG-63) to different concentrations of curcumin. Then, we characterized the effects on MG-63 cells using assays (cell viability, colony formation, cell cycle, wound healing, invasion), flow cytometry, Western blot, immunohistochemical analyses, and tumor xenograft.

Results

The half-maximal inhibitory of curcumin for MG-63 cells at 24 hours was 27.6 µM. The number of colonies of MG-63 cells was decreased obviously upon curcumin (10 and 20 µM) treatment. We also found increased accumulation of MG-63 cells in the G2/M phase upon curcumin (10 and 20 µM) treatment. Apoptosis was increased in 10 and 20 µM curcumin-treated MG-63 cells. After incubation of physically wounded cells for 24 hours, the percentage wound width increased upon curcumin exposure. Curcumin obviously decreased the expression of pJAK-2 and pSTAT-3 in MG-63 cells in a dose-dependent manner. Curcumin dose-dependently inhibited the proliferation, migration, and invasion of MG-63 cells and induced arrest of the G0/G1 phase and apoptosis by inhibiting the p-JAK2/p-STAT3 pathway. The linear correlativity between expression of p-JAK2 and STAT3 was very prominent, and both were closely associated with lung metastasis. In vivo study suggested that curcumin suppressed tumor growth through JAK2/STAT3 signaling.

Conclusion

Curcumin-mediated inhibition of the proliferation and migration of MG-63 cells was associated with inactivation of JAK/STAT signaling.

Chemotherapy in Nonmetastatic Osteosarcoma: Recent Advances and Implications for Developing Countries

PURPOSE

Osteosarcoma (OS) is a relatively chemosensitive primary bone tumor, with the peak age of onset occurring in late childhood and early adolescence. The treatment paradigm of nonmetastatic OS has typically been multimodality therapy, including neoadjuvant and adjuvant chemotherapy with definitive surgery. Over the years, various permutations and combinations of chemotherapeutic agents have been used. However, the majority of recent trials have still used high-dose methotrexate as the backbone, with cisplatin and doxorubicin (MAP). In the last decade, various strategies targeted to improving outcomes in OS have included the addition of a fourth drug to the three-drug MAP regimen, changing therapy according to histopathologic response and the addition of immunotherapies. Through this review, we sought to underscore a few pertinent issues related to chemotherapy in nonmetastatic OS, with special reference to challenges confronted in Indian settings.

METHODS

We reviewed the literature, focusing on studies comparing high-dose methotrexate and non-high-dose methotrexate-containing regimens. In addition, this review focuses on non-methotrexate-containing triple-drug therapy.

RESULTS

Although a high-dose methotrexate regimen has become standard of care in developed countries, there are few data to suggest that it is superior to a non-high-dose methotrexate regimen.

CONCLUSION

Developing countries with lack of infrastructure and logistics for high-dose methotrexate might resort to non-high-dose methotrexate-containing regimens with a simultaneous focus on early detection, decreasing abandonment, multidisciplinary clinics, improved surgery, and meticulous pathologic evaluations.

Silencing of cytoskeleton-associated protein 2 represses cell proliferation and induces cell cycle arrest and cell apoptosis in osteosarcoma cells

Osteosarcoma is the most common primary bone malignancy, mainly occurring in children and adolescents. Cytoskeleton-associated protein 2 (CKAP2), which plays important roles in cell proliferation, has been reported to be overexpressed in diverse human cancers. In the present study, we aimed at exploring the expression and functions of CKAP2 in osteosarcoma. The mRNA and protein expression of CKAP2 was analyzed on collected osteosarcoma and control bone cyst tissues. The results indicated that CKAP2 expression was remarkably elevated in osteosarcoma tissues compared with bone cysts tissues. The expression level of CKAP2 in osteosarcoma was associated with overall survival, tumor size and tumor stage. In addition, down-regulation of CKAP2 by RNA interference in osteosarcoma cell lines, MG63 and SW1353, caused a remarkable inhibition in cell proliferation in vitro and xenograft growth in nude mice. Silencing of CKAP2 also significantly induced G0/G1 arrest and cell apoptosis of osteosarcoma cells. Furthermore, phosphorylation levels of Janus kinase 2 (JAK2) and Signal transducers and activators of transcription 3 (STAT3) were significantly reduced in CKAP2 knockdown cells. The expression of downstream targets of JAK2/STAT3 signaling, Cyclin D1, Bcl-2 and survivin, was also decreased in CKAP2 knockdown cells. Such aberrations can be rescued by re-expression of RNAi-resistant CKAP2. Collectively, the present study indicates that CKAP2 is a potential oncogene by targeting JAK2/STAT3 signaling, and that CKAP2 may serve as a novel target for osteosarcoma therapy.

CD44 drives aggressiveness and chemoresistance of a metastatic human osteosarcoma xenograft model

Background

Osteosarcoma is the most common primary malignant bone tumor with a 5 year survival rate of up to 70%. However, patients with metastatic disease have still a very poor prognosis. Osteosarcoma metastasis models are essential to develop novel treatment strategies for advanced disease.

Methods

Based on a serial transplantation approach, we have established a U-2 OS osteosarcoma xenograft model with increased metastatic potential and compared it to other metastatic osteosarcoma models from international sources. Subclones with differing invasive potential were compared for genomic gains and losses as well as gene expression changes by several bioinformatic approaches. Based on the acquired results, the effects of a shRNA-mediated CD44 mRNA knockdown on migration, invasion and chemosensitivity were evaluated.

Results

The CD44 gene was part of an amplified region at chromosome 11p found in both U-2 OS subclones with enhanced metastatic potential but not in parental U-2 OS cells, corresponding with distinct CD44 overexpression. Accordingly, shRNA-mediated CD44 knockdown significantly attenuated osteosarcoma cell migration, invasion, and viability especially in the metastatic subclones of U-2 OS and Saos-2 cells. Metastatic subclones generally were hypersensitive against the integrin inhibitor cilengitide paralleled by alterations in integrin expression pattern following CD44 knock-down. Additionally, attenuation of CD44 expression sensitized these cell models against osteosarcoma chemotherapy with doxorubicin but not methotrexate and cisplatin.

Conclusions

The osteosarcoma xenograft models with increased metastatic potential developed in this study can be useful for identification of mechanisms driving metastasis and resistance towards clinically used and novel therapeutic regimens.

STK39, overexpressed in osteosarcoma, regulates osteosarcoma cell invasion and proliferation

Serine/threonine kinase 39 (STK39) is associated with hypertension, autism, Parkinson's disease and various types of cancer in recent years. This study investigated STK39 expression and possible roles in osteosarcoma using qPCR and western blot analysis. Compared to normal bone tissues, the mRNA and protein expression of STK39 was found to be upregulated in osteosarcoma. Using small interfering RNA transfection, STK39 was knocked down into two cell lines of osteosarcoma, U2OS and MG63, and the effects exerted on cell functioning were examined. The results showed that STK39 downregulation inhibited ostesarcoma cell proliferation and invasion. Moreover, STK39 knockdown in osteosarcoma cells significantly affected the expression of proteins connected to cell proliferation (proliferating cell nuclear antigen and p21) and invasion [Twist1, matrix metalloproteinase (MMP)2 and MMP9]. Phosphorylation of Smad2/3 was reduced by STK39 knock down. In conclusion, our data provide evidence that STK39 was overexpressed in osteosarcoma. STK39 may serve as an oncogene by adjusting the proliferation and invasion of osteosarcoma cells.

Upregulation and biological function of transmembrane protein 119 in osteosarcoma

Osteosarcoma is suggested to be caused by genetic and molecular alterations that disrupt osteoblast differentiation. Recent studies have reported that transmembrane protein 119 (TMEM119) contributes to osteoblast differentiation and bone development. However, the level of TMEM119 expression and its roles in osteosarcoma have not yet been elucidated. In the present study, TMEM119 mRNA and protein expression was found to be up-regulated in osteosarcoma compared with normal bone cyst tissues. The level of TMEM119 protein expression was strongly associated with tumor size, clinical stage, distant metastasis and overall survival time. Moreover, gene set enrichment analysis (GSEA) of the Gene Expression Omnibus (GEO) GSE42352 dataset revealed TMEM119 expression in osteosarcoma tissues to be positively correlated with cell cycle, apoptosis, metastasis and TGF-β signaling. We then knocked down TMEM119 expression in U2OS and MG63 cells using small interfering RNA, which revealed that downregulation of TMEM119 could inhibit the proliferation of osteosarcoma cells by inducing cell cycle arrest in G0/G1 phase and apoptosis. We also found that TMEM119 knockdown significantly inhibited cell migration and invasion, and decreased the expression of TGF-β pathway-related factors (BMP2, BMP7 and TGF-β). TGF-β application rescued the inhibitory effects of TMEM119 knockdown on osteosarcoma cell migration and invasion. Further in vitro experiments with a TGF-β inhibitor (SB431542) or BMP inhibitor (dorsomorphin) suggested that TMEM119 significantly promotes cell migration and invasion, partly through TGF-β/BMP signaling. In conclusion, our data support the notion that TMEM119 contributes to the proliferation, migration and invasion of osteosarcoma cells, and functions as an oncogene in osteosarcoma.

Distinct activity of the bone-targeted gallium compound KP46 against osteosarcoma cells - synergism with autophagy inhibition

Background

Osteosarcoma is the most frequent primary malignant bone tumor. Although survival has distinctly increased due to neoadjuvant chemotherapy in the past, patients with metastatic disease and poor response to chemotherapy still have an adverse prognosis. Hence, development of new therapeutic strategies is still of utmost importance.

Methods

Anticancer activity of KP46 against osteosarcoma cell models was evaluated as single agent and in combination approaches with chemotherapeutics and Bcl-2 inhibitors using MTT assay. Underlying mechanisms were tested by cell cycle, apoptosis and autophagy assays.

Results

KP46 exerted exceptional anticancer activity at the nanomolar to low micromolar range, depending on the assay format, against all osteosarcoma cell models with minor but significant differences in IC₅₀ values. KP46 treatment of osteosarcoma cells caused rapid loss of cell adhesion, weak cell cycle accumulation in S-phase and later signs of apoptotic cell death. Furthermore, already at sub-cytotoxic concentrations KP46 reduced the migratory potential of osteosarcoma cells and exerted synergistic effects with cisplatin, a standard osteosarcoma chemotherapeutic. Moreover, the gallium compound induced signs of autophagy in osteosarcoma cells. Accordingly, blockade of autophagy by chloroquine but also by the Bcl-2 inhibitor obatoclax increased the cytotoxic activity of KP46 treatment significantly, suggesting autophagy induction as a protective mechanism against KP46.

Conclusion

Together, our results identify KP46 as a new promising agent to supplement standard chemotherapy and possible future targeted therapy in osteosarcoma.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-017-0527-z) contains supplementary material, which is available to authorized users.

The clinical significance of changes in ezrin expression in osteosarcoma of children and young adults

Ezrin is a protein that functions as a cross-linker between actin cytoskeleton and plasma membrane. Its clinical role in osteosarcoma is unclear. The aim of this study was to investigate, in osteosarcoma, the prognostic value of ezrin expression at biopsy and changes in expression levels after preoperative chemotherapy. Thirty-eight newly diagnosed osteosarcoma patients aged 6-23 years were included. At diagnosis, 20 patients had localized disease, the others had distant metastases. Median follow-up was 75 months (range 13-135). Ezrin expression was assessed immunohistochemically in biopsy tissue and primary tumour specimens resected after chemotherapy. The influence on survival of changes in ezrin expression after chemotherapy was analysed. Ezrin expression was significantly higher after preoperative chemotherapy and changes compared to biopsy tissue were significantly lower in patients with early progression than in patients with relapse or no further evidence of disease (p = 0.006 and p = 0.002, respectively). Similarly, ezrin expression was higher after preoperative chemotherapy and exhibited less change in expression in deceased patients compared to patients surviving more than 5 years (both p = 0.001). Ezrin expression at biopsy was significantly associated with both histopathological aggressiveness (p < 0.001) and tumour size (p = 0.037). The results of this study provide evidence that changes in overexpression of ezrin due to preoperative chemotherapy could be a useful predictive and prognostic marker in patients with osteosarcoma.

Hypoxia-Induced WSB1 Promotes the Metastatic Potential of Osteosarcoma Cells

Intratumoral hypoxia occurs in many solid tumors, where it is associated with the development of metastatic character. However, the connections between these phenomena are not fully understood. In this study, we define an integrative role for the E3 ubiquitin ligase subunit WSB1. In primary osteosarcomas, increased levels of WSB1 correlated with pulmonary metastatic potential. RNAi-mediated attenuation of WSB1 or disruption of its E3 ligase activity potently suppressed tumor metastasis. Quantitative proteomic and functional analyses revealed that WSB1 ubiquitylates the Rho-binding protein RhoGDI2 and promotes its proteasomal degradation, thereby activating Rac1 to stimulate tumor cell motility and invasion. Our findings show how WSB1 regulates key steps of the metastatic cascade in hypoxia-driven osteosarcoma, and they highlight a candidate therapeutic target to potentially improve the survival of patients with metastatic disease.

Performance of Positron Emission Tomography and Positron Emission Tomography/Computed Tomography Using Fluorine-18-Fluorodeoxyglucose for the Diagnosis, Staging, and Recurrence Assessment of Bone Sarcoma: A Systematic Review and Meta-Analysis

To investigate the performance of fluorine-18-fluorodeoxyglucose (F-FDG) positron emission tomography (PET) and PET/computed tomography (CT) in the diagnosis, staging, restaging, and recurrence surveillance of bone sarcoma by systematically reviewing and meta-analyzing the published literature.To retrieve eligible studies, we searched the MEDLINE, Embase, and the Cochrane Central library databases using combinations of following Keywords: "positron emission tomography" or "PET," and "bone tumor" or "bone sarcoma" or "sarcoma." Bibliographies from relevant articles were also screened manually. Data were extracted and the pooled sensitivity, specificity, and diagnostic odds ratio (DOR), on an examination-based or lesion-based level, were calculated to appraise the diagnostic accuracy of F-FDG PET and PET/CT. All statistical analyses were performed using Meta-Disc 1.4.Forty-two trials were eligible. The pooled sensitivity and specificity of PET/CT to differentiate primary bone sarcomas from benign lesions were 96% (95% confidence interval [CI], 93-98) and 79% (95% CI, 63-90), respectively. For detecting recurrence, the pooled results on an examination-based level were sensitivity 92% (95% CI, 85-97), specificity 93% (95% CI, 88-96), positive likelihood ratio (PLR) 10.26 (95% CI, 5.99-17.60), and negative likelihood ratio (NLR) 0.11 (95% CI, 0.05-0.22). For detecting distant metastasis, the pooled results on a lesion-based level were sensitivity 90% (95% CI, 86-93), specificity 85% (95% CI, 81-87), PLR 5.16 (95% CI, 2.37-11.25), and NLR 0.15 (95% CI, 0.11-0.20). The accuracies of PET/CT for detecting local recurrence, lung metastasis, and bone metastasis were satisfactory. Pooled outcome estimates of F-FDG PET were less complete compared with those of PET/CT.F-FDG PET and PET/CT showed a high sensitivity for diagnosing primary bone sarcoma. Moreover, PET/CT demonstrated excellent accuracy for the staging, restaging, and recurrence surveillance of bone sarcoma. However, to avoid misdiagnosis, pathological examination or long-term follow-up should be carried out for F-FDG-avid lesions in patients with suspected bone sarcoma.

CD8+/FOXP3+-ratio in osteosarcoma microenvironment separates survivors from non-survivors: a multicenter validated retrospective study

Osteosarcoma is the most common primary bone tumor characterized by juvenile onset, tumor heterogeneity, and early pulmonary metastasis. Therapeutic improvement stagnates since more than two decades. Unlike major malignancies, biomarkers as prognostic factors at time of diagnosis are missing. Disease rareness hampers study recruitment of patient numbers sufficient to outweigh tumor heterogeneity. Here, we analyzed in a multicenter cohort the osteosarcoma microenvironment to reduce effects of tumor cell heterogeneity. We hypothesized that quantitative ratios of intratumoral CD8⁺T-cells to FOXP3⁺T-cells (CD8⁺/FOXP3⁺-ratios) provide strong prognostic information when analyzed by whole-slide imaging in diagnostic biopsies. We followed recommendations-for-tumor-marker-prognostic-studies (REMARK). From 150 included cases, patients with complete treatment were identified and assigned to the discovery (diagnosis before 2004) or the validation cohort (diagnosis 2004-2012). Highly standardized immunohistochemistry of CD8⁺ and FOXP3⁺, which was validated by methylation-specific gene analysis, was performed followed by whole-slide analysis and clinical outcome correlations. We observed improved estimated survival in patients with CD8⁺/FOXP3⁺-ratios above the median (3.08) compared to patients with lower CD8⁺/FOXP3⁺-ratios (p = 0.000001). No patients with a CD8⁺/FOXP3⁺-ratio above the third quartile died within the observation period (median follow-up 69 mo). Multivariate analysis demonstrated independence from current prognostic factors including metastasis and response to neoadjuvant chemotherapy. Data from an independent validation cohort confirmed improved survival (p = 0.001) in patients with CD8⁺/FOXP3⁺-ratios above 3.08. Multivariate analysis proofed that this observation was also independent from prognostic factors at diagnosis within the validation cohort. Intratumoral CD8⁺/FOXP3⁺-ratio in pretreatment biopsies separates patients with prolonged survival from non-survivors in osteosarcoma.

Pediatric bone sarcoma: diagnostic performance of ¹⁸F-FDG PET/CT versus conventional imaging for initial staging and follow-up

OBJECTIVE

The purpose of this study was to compare the diagnostic performance of (18)F-FDG PET/CT and conventional imaging for staging and follow-up of pediatric osteosarcoma and skeletal Ewing sarcoma.

MATERIALS AND METHODS

We calculated sensitivity, specificity, and accuracy of PET/CT and conventional imaging (CT, MRI, bone scanning) for sites of disease and number of lesions. Diagnostic benefit, defined as better characterization of lesions, was evaluated on a per-scan basis, comparing PET/CT and conventional imaging.

RESULTS

A total of 412 lesions were characterized by imaging in 64 patients (20, osteosarcoma; 44, Ewing sarcoma). For osteosarcoma patients PET/CT was available only at follow-up, where it proved more accurate than conventional imaging for the detection of bone lesions (accuracy, 95% vs 67% for CT and 86% for MRI) and complementary to CT in evaluating lung nodules (sensitivity, 84% vs 94%; specificity, 79% vs 71%) with diagnostic benefit in 18% of examinations. In patients with Ewing sarcoma, PET/CT tended to perform better during follow-up than at initial staging (accuracy, 85% vs 69%). For lung findings, PET/CT was more specific than CT but was less sensitive. The diagnostic benefit of PET/CT was greater at staging (28%) than during followup (9%). On a per-patient basis, PET/CT provided diagnostic benefit in 21 of 44 patients with Ewing sarcoma and nine of 20 patients with osteosarcoma at least once during clinical management.

CONCLUSION

FDG PET/CT provides diagnostic benefit in Ewing sarcoma and osteosarcoma, with the exception of small lung nodules. Prospective studies are needed to define the best imaging algorithm and combination of tests in the staging and follow-up of patients with pediatric bone sarcoma.

Interleukin-11 receptor α is overexpressed in human osteosarcoma, and near-infrared-labeled IL-11Rα imaging agent could detect osteosarcoma in mouse tumor xenografts

IL-11Rα is an important cytokine receptor that links oxidative stress and compensatory proliferation. Mounting evidence has demonstrated that IL-11Rα regulates autoimmune demyelination and the invasion and proliferation of cancer cells, making it an important therapeutic target for molecular targeted therapy. Moreover, overexpression of IL-11Rα indicates a poor long-term prognosis in cancer patients. However, the expression status and its potential as a biomarker for diagnosis, tumor imaging, and prognosis in osteosarcoma remain to be determined. We report here that IL-11Rα is highly expressed in osteosarcoma and near-infrared (NIR)-labeled IL-11Rα imaging agent could detect osteosarcoma in mouse tumor xenografts. In a panel of human osteosarcoma specimens, IL-11Rα protein was positively stained in most cases by immunohistochemistry. Western blot analysis and flow cytometry showed that IL-11Rα was overexpressed in osteosarcoma SOSP-9607 cells. Cell-binding assay demonstrated specific binding of the IL-11Rα targeted imaging agent to osteosarcoma SOSP-9607 cells in vitro. In addition, administration of an IL-11Rα targeted imaging agent in a nude mice orthotopic model resulted in selective accumulation of NIR fluorescent signals in the bone tumor as well as several metabolic organs. These results indicate that IL-11Rα is a potential target for the development of molecular targeted therapy and noninvasive tumor imaging in human osteosarcoma. Furthermore, NIR-labeled IL-11Rα imaging agent is a promising lead for the development of a tumor in vivo imaging method at the molecular level in the management of human osteosarcoma.

Zinc finger X-chromosomal protein (ZFX) promotes solid agar colony growth of osteosarcoma cells

Zinc finger X-chromosomal protein (ZFX) is a member of the zinc finger family of proteins. The importance of ZFX in several cancer types, including prostate cancer, laryngeal squamous cell carcinoma, and glioma, has been addressed. However, the role of ZFX in human osteosarcoma remains unknown. Here we investigated the phenotype of ZFX knockdown on cell proliferation and in vitro tumorigenesis using lentivirus-mediated loss-of-function strategy. The results demonstrated that the proliferation and colony formation ability of human osteosarcoma Saos-2 and MG63 cells was impaired by ZFX small interfering RNA (siRNA)-expressing lentivirus. Moreover, loss of ZFX led to G0/G1 phase cell cycle arrest and a significant increase of cells in the sub-G1 fraction, indicating that ZFX functions as an oncogene in the malignant proliferation process in osteosarcoma. Furthermore, ZFX siRNA may have an antitumorigenic effect on osteosarcoma cells. Our findings hold important significance for RNA interference-mediated cancer gene therapy for human osteosarcoma.

Neuropilin-1 is overexpressed in osteosarcoma and contributes to tumor progression and poor prognosis

AIM

Neuropilin (NRP)-1, a co-receptor for vascular endothelial growth factor (VEGF), plays an important role in angiogenesis and malignant progression of many cancers. However, the involvement of NRP-1 in osteosarcoma is not completely understood. The aim of this study was to investigate the expression pattern and clinical significance of NRP-1 in human osteosarcoma.

METHODS

NRP-1 mRNA and protein expression levels were detected by RT-PCR and Western blot assays, respectively, using 166 pairs of osteosarcoma and noncancerous bone tissues. Then, the association of NRP-1 expression with clinicopathological factors or survival of osteosarcoma patients was further evaluated.

RESULTS

RT-PCR and Western blot assays revealed that NRP-1 expression in osteosarcoma tissues was significantly higher than that in corresponding noncancerous bone tissues at both mRNA and protein levels (both P < 0.001). In addition, high NRP-1 expression more frequently occurred in osteosarcoma tissues with advanced clinical stage (P = 0.006), positive distant metastasis (P = 0.01) and poor response to chemotherapy (P = 0.006). Moreover, osteosarcoma patients with high NRP-1 expression had significantly shorter overall survival and disease-free survival (both P < 0.001) when compared with patients with the low expression of NRP-1. On Cox multivariate analysis, NRP-1 overexpression was an independent and significant prognostic factor to predict poor overall survival and disease-free survival (both P = 0.001).

CONCLUSION

This is the first study to reveal that NRP-1 overexpression may be related to the prediction of metastasis potency, response to chemotherapy and poor prognosis for osteosarcoma patients, suggesting that NRP-1 may serve as a prognostic marker for the optimization of clinical treatments.

Upregulation of SOX9 in osteosarcoma and its association with tumor progression and patients' prognosis

Objective

SOX9 plays an important role in bone formation and tumorigenesis. However, its involvement in osteosarcoma is still unclear. The aim of this study was to investigate the expression pattern and the clinical significance of SOX9 in human osteosarcoma.

Methods

SOX9 mRNA and protein expression levels were detected by RT-PCR and Western blot assays, respectively, using 30 pairs of osteosarcoma and noncancerous bone tissues. Then, immunohistochemistry was performed to analyze the association of SOX9 expression in 166 osteosarcoma tissues with clinicopathological factors or survival of patients.

Results

SOX9 expression at mRNA and protein levels were both significantly higher in osteosarcoma tissues than those in corresponding noncancerous bone tissues (both P < 0.001). Immunohistochemical staining indicated that SOX9 localized to the nucleus and high SOX9 expression was observed in 120 of 166 (72.3%) osteosarcoma specimens. In addition, high SOX9 expression was more frequently occurred in osteosarcoma tissues with advanced clinical stage (P = 0.02), positive distant metastasis (P = 0.008) and poor response to chemotherapy (P = 0.02). Osteosarcoma patients with high SOX9 expression had shorter overall survival and disease-free survival (both P < 0.001). Furthermore, the multivariate analysis confirmed that upregulation of SOX9 was an independent and significant prognostic factor to predict poor overall survival and disease-free survival (both P = 0.006).

Conclusions

Our data show for the first time that SOX9 is upregulated in aggressive osteosarcoma tissues indicating that SOX9 may participate in the osteosarcoma progression. More importantly, SOX9 status is a useful prognostic factor for predicting the prognosis of osteosarcoma, suggesting that SOX9 may contribute to the optimization of clinical treatments for osteosarcoma patients.

Virtual slides

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1318085636110837.

Overexpression of fibroblast activation protein and its clinical implications in patients with osteosarcoma

BACKGROUND AND OBJECTIVES

Fibroblast activation protein (FAP) expression has been detected in fibroblastic component of osteosarcomas. The aim of this study was to analyze the correlation of FAP expression with the clinicopathological features of osteosarcoma.

METHODS

FAP mRNA and protein expression levels in human osteosarcoma tissues were, respectively detected by RT-PCR, Western blot, and immunohistochemistry assays.

RESULTS

FAP mRNA and protein expression were both higher in osteosarcoma than in corresponding noncancerous bone tissues (both P < 0.001). In addition, the immunohistochemistry assay found that all patients showed positive FAP expression. Higher FAP expression was significantly correlated with advanced clinical stage (P = 0.006), high histological grade (P = 0.02), positive metastatic status (P = 0.01), shorter overall (P < 0.001), and disease-free (P < 0.001) survival in osteosarcoma patients. Furthermore, Cox multivariate analysis showed that FAP overexpression was an independent prognostic factor for predicting both overall and disease-free survival of osteosarcoma patients.

CONCLUSION

Expression of FAP in osteosarcoma could be adopted as a candidate biomarker for the diagnosis of clinical stage, histological grade and metastasis, and for assessing prognosis, indicating for the first time that FAP may play an important role in tumor development and progression in osteosarcoma. FAP might be considered as a novel therapeutic target against this cancer.

The Prognostic Role of Ezrin Immunoexpression in Osteosarcoma: A Meta-Analysis of Published Data

Background

The significance of ezrin immunoexpression and prognosis for osteosarcoma is still controversial. The aim was to provide a meta-analysis for ezrin immunoexpression and prognostic features of osteosarcoma patients.

Methods

A detailed search was made in MEDLINE, EMBASE and the Web of Knowledge for relevant original articles published in English; methodological quality of the included studies was also assessed. Two reviewers extracted data independently. Studies were pooled and summary hazard ratios (HRs) and odds ratio (ORs) with corresponding confidence intervals (CIs) were calculated.

Results

Final analysis of 318 patients from 5 eligible studies was performed. Combined HR of ezrin immunohistochemical staining suggested that positive immunoexpression had an unfavorable impact on osteosarcoma patients' overall survival (n = 223 in 4 studies; HR = 4.79; 95% CI: 1.50–15.30; P = 0.008) but not on event-free survival (n = 202 in 3 studies; HR = 1.59; 95% CI: 0.61–4.15; P = 0. 0.342). Combined OR of ezrin immunohistochemical staining indicated that positive immunoexpression was associated with recurrence (n = 134 in 2 studies; OR = 3.79; 95% CI: 1.49–9.64; P = 0.005) but not with serum ALP level (n = 160 in 2 studies; OR = 2.16; 95% CI: 0.09–52.50; P = 0.637) and histological response to neoadjuvant chemotherapy(n = 260 in 4 studies; OR = 0.87; 95% CI: 0.37–2.03; P = 0.740).

Conclusions

The results of this meta-analysis suggest that ezrin positive immunoexpression confers a higher risk of recurrence and a worse survival in osteosarcoma patients. Large prospective studies are needed to provide solid data to investigate the precise prognostic significance of ezrin.

Synergistic relationship between dipeptidyl peptidase IV and neutral endopeptidase expression and the combined prognostic significance in osteosarcoma patients

Neutral endopeptidase (NEP/CD10) and dipeptidyl peptidase IV (DPP IV/CD26) are both ubiquitous glycopeptidases which play important roles in tumor pathogenesis and development. The aim of this study was to investigate the expression patterns and the prognostic significance of CD10 and CD26 in osteosarcoma patients. CD10 and CD26 expression in 116 pairs of primary osteosarcoma and corresponding noncancerous bone tissue samples from the same specimens were detected by immunohistochemistry. The Spearman's correlation was calculated between the expression levels of CD10 and CD26 in osteosarcoma tissues. The associations of CD10 and CD26 expression with the clinicopathologic features and with the prognosis of osteosarcoma were subsequently assessed. Both CD10 expression and CD26 expression in osteosarcoma tissues were significantly higher than those in corresponding noncancerous bone tissue samples (both P < 0.001). Overexpression of CD10 and CD26 were respectively observed in 68.10 % (79/116) and 70.69 % (82/116) of osteosarcoma tissues. A significant correlation was found between CD10 expression and CD26 expression in osteosarcoma tissues (r = 0.83, P < 0.001). In addition, combined overexpression of CD10 and CD26 was observed in 52.59 % (61/116) of osteosarcoma tissues. CD10-high/CD26-high expression was significantly correlated with advanced clinical stage (P = 0.001), positive metastatic status (P = 0.001), shorter overall (P < 0.001) and disease-free (P < 0.001) survival in patients with osteosarcomas. Furthermore, multivariate survival analysis showed that clinical stage, metastatic status, CD10 expression, CD26 expression and combined expression of CD10/CD26 were all independent prognostic factors for predicting both overall and disease-free survival of osteosarcoma patients. Interestingly, combined expression of CD10/CD26 had a better prognostic value than other features. This retrospective study offer the convincing evidence for the first time that the overexpression of CD10 or CD26 may be an important feature of human osteosarcomas, and the combined expression of CD10/CD26 may be an efficient prognostic indicator for this disease.

Increased expression of CD24 is associated with tumor progression and prognosis in patients suffering osteosarcoma

OBJECTIVE

As a small heavily glycosylated mucin-like glycosyl-phosphatidylinositol-anchored cell surface protein, CD24 plays an important role in carcinogenesis of various human malignancies. However, its involvement in osteosarcoma is still unclear. The aim of this study was to investigate the expression pattern and the clinical significance of CD24 in human osteosarcoma.

METHODS

CD24 mRNA and protein expression levels were, respectively, detected by RT-PCR and Western blot assays using 30 pairs of osteosarcoma and noncancerous bone tissues. Then, immunohistochemistry was performed to analyze the association of CD24 expression in 166 osteosarcoma tissues with clinicopathological factors or survival of patients.

RESULTS

CD24 expression at mRNA and protein levels were both significantly higher in osteosarcoma tissues than those in corresponding noncancerous bone tissues (both P < 0.001). In addition, CD24 protein was positively expressed in 129 of 166 (77.7 %) osteosarcoma specimens with a cytoplasmic and membraneous staining, and also increased in the osteosarcoma specimens with advanced clinical stage (P = 0.01) and positive distant metastasis (P = 0.005). The univariate and multivariate analyses showed that osteosarcoma patients with high CD24 expression had poorer overall and disease-free survival, and high CD24 expression was an independent prognostic factor for both overall and disease-free survival.

CONCLUSION

The aforementioned findings offer convincing evidence for the first time that the increased expression of CD24 is correlated with tumor aggressiveness and tumor metastasis of osteosarcoma, and this molecule is an independent prognostic marker for osteosarcoma patients.

Human osteosarcoma CD49f(-)CD133(+) cells: impaired in osteogenic fate while gain of tumorigenicity

The biological relationships among self-renewal, tumorigenicity, and lineage differentiation of human osteosarcoma-initiating cells (OSIC) remain elusive, making it difficult to identify and distinguish OSIC from osteosarcoma-forming cells (OSFC) for developing OSIC-targeted therapies. Using a new inverse lineage tracking strategy coupled with serial human-to-mouse xenotransplantation, we identified a subpopulation of osteosarcoma cells with OSIC-like properties and sought to distinguish them from their progeny, OSFC. We found that serial transplantation of cells from different osteosarcoma cell lines and primary osteosarcoma tissues progressively increased the CD49f⁺ subpopulation composing the bulk of the osteosarcoma mass. These CD49f⁺ cells displayed characteristics of OSFC: limited in vivo tumorigenicity, weak lineage differentiation, more differentiated osteogenic feature, and greater chemo-sensitivity. By contrast, their parental CD49f⁻CD133⁺ cells had an inhibited osteogenic fate, together with OSIC-like properties of self-renewal, strong tumorigenicity, and differentiation to CD49f⁺ progeny. Hence, the CD49f⁻CD133⁺ phenotype appears to identify OSIC-like cells that possess strong tumorigenicity correlated with an impaired osteogenic fate and the ability to initiate tumor growth through generation of CD49f⁺ progeny. These findings advance our understanding of OSIC-like properties and, for the first time, provide a much-needed distinction between OSIC and OSFC in this cancer.

Global gene expression profiling of human osteosarcomas reveals metastasis-associated chemokine pattern

Global gene expression analysis was performed on a panel of 23 osteosarcoma samples of primary and metastatic origin using the Applied Biosystems Gene Expression Array System. When comparing the primary tumours with the metastases, we found a significantly increased expression of genes involved in immunological processes, for example coding for cytokines and chemokines, in the metastatic samples. In addition, a comparison of the gene expression in primary samples from patients with or without metastases demonstrated that patients who later developed metastases had high expression of the chemokine (C-X-C motif) receptor 4 (CXCR4), similar to the metastatic samples, suggesting that these signal molecules play an important role in promoting metastasis. Increased knowledge of mechanisms and interactions between specified molecular signalling pathways in osteosarcomas could lead to a more rational strategy for development of targeted therapy.

Difference in pre- and postchemotherapy vascular endothelial growth factor levels as a prognostic indicator in osteosarcoma

This retrospective analysis examined the difference in pre- and postchemotherapy levels of vascular endothelial growth factor (VEGF) as an indicator of osteosarcoma prognosis. VEGF protein levels were assessed immunohistochemically in primary tumour samples from 61 osteosarcoma patients diagnosed between February 2001 and July 2005. The difference in pre- and postchemotherapy VEGF protein reduction levels was categorized into weak (23 patients) and strong (38 patients). The 5-year survival rate was significantly lower in the weak VEGF reduction group (34.8%) than in the strong VEGF reduction group (73.7%). The weak VEGF reduction group had significantly higher rates of metastasis and recurrence. Multivariate analysis confirmed that the change in VEGF was an independent and significant factor for predicting a good prognosis. The analysis of VEGF will enable clinicians to tailor surgery and chemotherapy regimens more appropriately, earlier in the disease process.

Osteosarcoma: Differential Diagnostic Considerations

Accurate diagnosis of bone-forming tumors, including correct subclassification of osteogenic sarcoma is critical for determination of appropriate clinical management and prediction of patient outcome. The morphologic spectrum of osteogenic sarcoma is extensive, however, and its histologic mimics are numerous. This review focuses on the major differential diagnoses of the specific subtypes of osteosarcoma, presents summaries of various diagnoses, and provides tips to overcoming pitfalls in diagnosis.

TSSC3 overexpression associates with growth inhibition, apoptosis induction and enhances chemotherapeutic effects in human osteosarcoma

Loss of expression of TSSC3, an apoptosis-related imprinted gene, has been reported in several cases of malignant tumors. However, the roles and mechanisms of TSSC3 in human osteosarcoma remain to be defined. In this study, we found TSSC3 to be downregulated during osteosarcoma transformation and progression in osteosarcoma cell lines and tissues. The SaOS2 cell line was used to further evaluate the precise role of TSSC3 in osteosarcoma development. Overexpression of TSSC3 markedly reduced cell vitality and growth, colony formation, Ki67 expression as well as cell cycle arrest in the G(0)/G(1) phase. Consistently, TSSC3 overexpression was associated with increased apoptosis assayed by annexin V/propidium iodide and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling staining. Subcutaneous injection of TSSC3 overexpressing SaOS2 cells into athymic nude mice showed that TSSC3 also inhibited tumorigenesis through growth inhibition and apoptosis induction in vivo. Further mechanistic studies revealed that the mitochondrial apoptosis pathway was required for TSSC3-mediated cell apoptosis. These findings support a suppressor role for TSSC3 in osteosarcoma development by regulating apoptosis. In addition, constitutive TSSC3 expression greatly enhanced the sensitivity of human osteosarcoma cells to the chemotherapeutic drugs cisplatin and epirubicin. Conversely, TSSC3 knockdown increased SaOS2 cell growth and decreased apoptosis in vitro and in vivo and reduced sensitivity of the cells to chemotherapy. This is the first study to demonstrate that TSSC3 has a potent tumor suppressor role in osteosarcoma, probably by inhibition of growth and induction of apoptosis via the mitochondrial apoptosis pathway.

Expressions of p53, c-MYC, BCL-2 and apoptotic index in human osteosarcoma and their correlations with prognosis of patients

BACKGROUND

Nowadays it remains a controversial issue whether a correlation exists between the apoptosis rate of tumor tissue and the prognosis of the patients. The aim of the study is to investigate the relationships of apoptotic genes and apoptotic index of osteosarcoma tissue to prognosis of the patients, meanwhile to explore the valid prognostic biomarkers of osteosarcoma that will enhance efficacy of clinical treatments for osteosarcoma.

METHODS

In our studies, the immunohistochemical ABC and terminal DNA breakpoints in situ 3-hydroxy end labeling (TUNEL) techniques were used to detect the expressions of p53, c-MYC, BCL-2 and apoptotic index in 56 osteosarcoma specimens. The relationships between apoptotic genes expression and apoptotic index in osteosarcoma tissue and their correlations with pathologic classification and prognosis of osteosarcoma cases were analyzed.

RESULTS

We found that the expressions of p53, c-MYC, and BCL-2 were negatively correlated with apoptotic index of osteosarcoma tissue, were not correlated with pathological types of osteosarcoma, and were closely related to prognosis of the patients. Moreover, apoptotic index of osteosarcoma tissue was positively correlated with the long term survival of the patients.

CONCLUSION

We concluded that the expressions of p53, c-MYC, BCL-2 protein and apoptotic index could be used as potential biomarks for predicting the progression and prognosis of osteosarcoma, and for optimizing clinical treatments.

Primary malignant bone tumors--recent developments

Primary malignant bone tumors are rare sarcomas with an estimated frequency of about 2900 new cases per year; they constitute less than 0.2% of all cancers diagnosed in the United States. The diagnosis and management of these neoplasms require a team approach, which includes orthopaedic surgeons, radiologists, pathologists, and oncologists. With this approach and current treatment modalities, the 5-year survival for the most common malignant bone tumors, osteosarcoma and Ewing sarcoma, are 70% and 60%, respectively. This review will summarize recent developments and advances in molecular pathogenesis of the more common primary malignant bone neoplasms.

Clinical applications in molecular imaging

Molecular imaging is aimed at the noninvasive in vivo characterization and measurement of processes at a cellular and molecular level with clinical imaging methods. Contrast agents are constructed to target markers that are specific either for certain diseases or for functional states of specialized tissues. Efforts are currently focused mainly on processes involved in angiogenesis, inflammation, and apoptosis. Cell tracking is performed for diagnostic purposes as well as for monitoring of novel cell therapies. Visualization of these processes would provide more precise information about disease expansion as well as treatment response, and could lead to a more individualized therapy for patients. Many attempts have shown promising results in preclinical studies; however, translation into the clinic remains a challenge. This applies especially to paediatrics because of more stringent safety concerns and the low prevalence of individual diseases. The most promising modalities for clinical translation are nuclear medicine methods (positron emission tomography [PET] and single photon emission CT [SPECT]) due to their high sensitivity, which allows concentrations below biological activity. However, special dose consideration is required for any application of ionizing radiation especially in children. While very little has been published on molecular imaging in a paediatric patient population beyond fluorodeoxyglucose (FDG)-PET and metaiodobenzylguanidine (MIBG) tracers, this review will attempt to discuss approaches that we believe have promise for paediatric imaging. These will include agents that already reached clinical trials as well as preclinical developments with high potential for clinical application.