PURPOSE Osteosarcoma and Ewing's sarcoma are the most common bone tumors in children and adolescents. Despite intensive chemotherapy, patients with advanced disease have a poor prognosis,... Show morePURPOSE Osteosarcoma and Ewing's sarcoma are the most common bone tumors in children and adolescents. Despite intensive chemotherapy, patients with advanced disease have a poor prognosis, illustrating the need for alternative therapies. Sarcoma cells are susceptible to the cytolytic activity of resting natural killer (NK) cells which can be improved by interleukin (IL)-15 stimulation. In this study, we explored whether the cytolytic function of resting NK cells can be augmented and specifically directed toward sarcoma cells by antibody-dependent cellular cytotoxicity (ADCC). EXPERIMENTAL DESIGN Epidermal growth factor receptor (EGFR) expression was examined on osteosarcoma and Ewing's sarcoma cell lines by flow cytometry and in osteosarcoma biopsy and resection specimens by immunohistochemistry. Cetuximab-mediated ADCC by NK cells from osteosarcoma patients and healthy controls was measured with 4-hour (51)Cr release assays. RESULTS EGFR surface expression was shown on chemotherapy-sensitive and chemotherapy-resistant osteosarcoma cells (12/12), most primary osteosarcoma cultures (4/5), and few Ewing's sarcoma cell lines (2/7). In the presence of cetuximab, the cytolytic activity of resting NK cells against all EGFR-expressing sarcoma cells was substantially increased and comparable with that of IL-15-activated NK cells. Surface EGFR expression on primary osteosarcoma cultures correlated with EGFR expression in the original tumor. The cytolytic activity of osteosarcoma patient-derived NK cells against autologous tumor cells was as efficient as that of NK cells from healthy donors. CONCLUSION Our data show that the cytolytic potential of resting NK cells can be potentiated and directed toward osteosarcoma cells with cetuximab. Therefore, cetuximab-mediated immunotherapy may be considered a novel treatment modality in the management of advanced osteosarcoma. Show less
High-grade osteosarcoma occurs predominantly in adolescents and young adults and has an overall survival rate of about 60%, despite chemotherapy and surgery. Therefore, novel treatment modalities... Show moreHigh-grade osteosarcoma occurs predominantly in adolescents and young adults and has an overall survival rate of about 60%, despite chemotherapy and surgery. Therefore, novel treatment modalities are needed to prevent or treat recurrent disease. Natural killer (NK) cells are lymphocytes with cytotoxic activity toward virus-infected or malignant cells. We explored the feasibility of autologous and allogeneic NK cell-mediated therapies for chemotherapy-resistant and chemotherapy-sensitive high-grade osteosarcoma. The expression by osteosarcoma cells of ligands for activating NK cell receptors was studied in vitro and in vivo, and their contribution to NK cell-mediated cytolysis was studied by specific antibody blockade. Chromium release cytotoxicity assays revealed chemotherapy-sensitive and chemotherapy-resistant osteosarcoma cell lines and osteosarcoma primary cultures to be sensitive to NK cell-mediated cytolysis. Cytolytic activity was strongly enhanced by IL-15 activation and was dependent on DNAM-1 and NKG2D pathways. Autologous and allogeneic activated NK cells lysed osteosarcoma primary cultures equally well. Osteosarcoma patient-derived NK cells were functionally and phenotypically unimpaired. In conclusion, osteosarcoma cells, including chemoresistant variants, are highly susceptible to lysis by IL-15-induced NK cells from both allogeneic and autologous origin. Our data support the exploitation of NK cells or NK cell-activating agents in patients with high-grade osteosarcoma. Show less
High-grade osteosarcoma occurs predominantly in adolescents and young adults and has an overall survival rate of about 60%, despite chemotherapy and surgery. Therefore, novel treatment modalities... Show moreHigh-grade osteosarcoma occurs predominantly in adolescents and young adults and has an overall survival rate of about 60%, despite chemotherapy and surgery. Therefore, novel treatment modalities are needed to prevent or treat recurrent disease. Natural killer (NK) cells are lymphocytes with cytotoxic activity toward virus-infected or malignant cells. We explored the feasibility of autologous and allogeneic NK cell-mediated therapies for chemotherapy-resistant and chemotherapy-sensitive high-grade osteosarcoma. The expression by osteosarcoma cells of ligands for activating NK cell receptors was studied in vitro and in vivo, and their contribution to NK cell-mediated cytolysis was studied by specific antibody blockade. Chromium release cytotoxicity assays revealed chemotherapy-sensitive and chemotherapy-resistant osteosarcoma cell lines and osteosarcoma primary cultures to be sensitive to NK cell-mediated cytolysis. Cytolytic activity was strongly enhanced by IL-15 activation and was dependent on DNAM-1 and NKG2D pathways. Autologous and allogeneic activated NK cells lysed osteosarcoma primary cultures equally well. Osteosarcoma patient-derived NK cells were functionally and phenotypically unimpaired. In conclusion, osteosarcoma cells, including chemoresistant variants, are highly susceptible to lysis by IL-15-induced NK cells from both allogeneic and autologous origin. Our data support the exploitation of NK cells or NK cell-activating agents in patients with high-grade osteosarcoma. Show less
Purpose: High-grade osteosarcoma is a malignant primary bone tumor with a peak incidence in adolescence. Overall survival (OS) of patients with resectable metastatic disease is approximately 20%.... Show morePurpose: High-grade osteosarcoma is a malignant primary bone tumor with a peak incidence in adolescence. Overall survival (OS) of patients with resectable metastatic disease is approximately 20%. The exact mechanisms of development of metastases in osteosarcoma remain unclear. Most studies focus on tumor cells, but it is increasingly evident that stroma plays an important role in tumorigenesis and metastasis. We investigated the development of metastasis by studying tumor cells and their stromal context. Experimental Design: To identify gene signatures playing a role in metastasis, we carried out genome-wide gene expression profiling on prechemotherapy biopsies of patients who did (n = 34) and patients who did not (n = 19) develop metastases within 5 years. Immunohistochemistry (IHC) was performed on pretreatment biopsies from 2 additional cohorts (n = 63 and n = 16) and corresponding postchemotherapy resections and metastases. Results: A total of 118/132 differentially expressed genes were upregulated in patients without metastases. Remarkably, almost half of these upregulated genes had immunological functions, particularly related to macrophages. Macrophage-associated genes were expressed by infiltrating cells and not by osteosarcoma cells. Tumor-associated macrophages (TAM) were quantified with IHC and associated with significantly better overall survival (OS) in the additional patient cohorts. Osteosarcoma samples contained both M1-(CD14/HLA-DR alpha positive) and M2-type TAMs (CD14/CD163 positive and association with angiogenesis). Conclusions: In contrast to most other tumor types, TAMs are associated with reduced metastasis and improved survival in high-grade osteosarcoma. This study provides a biological rationale for the adjuvant treatment of high-grade osteosarcoma patients with macrophage activating agents, such as muramyl tripeptide. Clin Cancer Res; 17(8); 2110-9. (C) 2011 AACR. Show less
Multiple osteochondromas (MO) is an autosomal dominant disorder caused by germline mutations in EXT1 and/or EXT2. In contrast, solitary osteochondroma (SO) is nonhereditary. Products of the EXT... Show moreMultiple osteochondromas (MO) is an autosomal dominant disorder caused by germline mutations in EXT1 and/or EXT2. In contrast, solitary osteochondroma (SO) is nonhereditary. Products of the EXT gene are involved in heparan sulfate (HS) biosynthesis. In this study, we investigated whether osteochondromas arise via either loss of heterozygosity (2 hits) or haploinsufficiency. An in vitro three-dimensional chondrogenic pellet model was used to compare heterozygous bone marrow-derived mesenchymal stem cells (MSCs EXTwt/-) of MO patients with normal MSCs and the corresponding tumor specimens (presumed EXT-/-). We demonstrated a second hit in EXT in five of eight osteochondromas. HS chain length and structure, in vitro chondrogenesis, and EXT expression levels were identical in both EXTwt/- and normal MSCs. Immunohistochemistry for HS, HS proteoglycans, and HS-dependent signaling pathways (eg, TGF-beta/BMP, Wnt, and PTHLH) also showed no differences. The cartilaginous cap of osteochondroma contained a mixture of HS-positive and HS-negative cells. Because a heterozygous EXT mutation does not affect chondrogenesis, EXT, HS, or downstream signaling pathways in MSCs, our results refute the haploinsufficiency theory. We found a second hit in 63% of analyzed osteochondromas, supporting the hypothesis that osteochondromas arise via loss of heterozygosity. The detection of the second hit may depend on the ratio of HS-positive (normal) versus HS-negative (mutated) cells in the cartilaginous cap of the osteochondroma. (Am J Pathol 2010, 177:1946-1957; DOI: 10.2353/ajpath.2010.100296) Show less
Introduction. Resection of pulmonary metastases has previously been reported to improve Outcome in high-grade osteosarcoma (OS) patients. Factors influencing Survival in OS patients with pulmonary... Show moreIntroduction. Resection of pulmonary metastases has previously been reported to improve Outcome in high-grade osteosarcoma (OS) patients. Factors influencing Survival in OS patients with pulmonary metastases are important for clinical decision making. Methods. All 88 OS patients with pulmonary metastases either at diagnosis or during follow-up treated at the Leiden University Medical Center between January 1, 1990 and January 1, 2008 under the age of 40 were included in this Study, including 79 cases of conventional, 8 cases of telangiectatic and 1 case of small cell OS. Results. In total, 56 of 88 patients with pulmonary metastases were treated by metastasectomy. Resectability Of pulmonary metastases was the main prognostic factor. In patients with primary non-metastatic OS, a longer relapse free interval to Pulmonary metastases was significantly associated with better survival (P=0.02). Independent risk factors determining worse survival after metastasectomy in multivariate analysis were male sex (P=0.05), higher number of pulmonary nodules (P=0.03), and non-necrotic metastases (P=0.04). Whether Surgery for recurrent pulmonary metastases was performed did not influence Survival. Histological Subtype of the primary tumor, histological response in the primary tumor after neoadjuvant chemotherapy, occurrence of local relapse, local resection or amputation of the primary tumor and age at diagnosis did not influence Outcome. Conclusion. This cohort of patients with detailed follow-up data enabled US to identify important risk factors determining Survival in OS patients with pulmonary metastases. We demonstrate that after repeated metastasectomies, a subset of patients can be cured. Pediatr Blood Cancer 2010;54:216-221. (C) 2009 Wiley-Liss, Inc. Show less
INTRODUCTION: Resection of pulmonary metastases has previously been reported to improve outcome in high-grade osteosarcoma (OS) patients. Factors influencing survival in OS patients with pulmonary... Show moreINTRODUCTION: Resection of pulmonary metastases has previously been reported to improve outcome in high-grade osteosarcoma (OS) patients. Factors influencing survival in OS patients with pulmonary metastases are important for clinical decision making. METHODS: All 88 OS patients with pulmonary metastases either at diagnosis or during follow-up treated at the Leiden University Medical Center between January 1, 1990 and January 1, 2008 under the age of 40 were included in this study, including 79 cases of conventional, 8 cases of telangiectatic and 1 case of small cell OS. RESULTS: In total, 56 of 88 patients with pulmonary metastases were treated by metastasectomy. Resectability of pulmonary metastases was the main prognostic factor. In patients with primary non-metastatic OS, a longer relapse free interval to pulmonary metastases was significantly associated with better survival (P = 0.02). Independent risk factors determining worse survival after metastasectomy in multivariate analysis were male sex (P = 0.05), higher number of pulmonary nodules (P = 0.03), and non-necrotic metastases (P = 0.04). Whether surgery for recurrent pulmonary metastases was performed did not influence survival. Histological subtype of the primary tumor, histological response in the primary tumor after neo-adjuvant chemotherapy, occurrence of local relapse, local resection or amputation of the primary tumor and age at diagnosis did not influence outcome. CONCLUSION: This cohort of patients with detailed follow-up data enabled us to identify important risk factors determining survival in OS patients with pulmonary metastases. We demonstrate that after repeated metastasectomies, a subset of patients can be cured. Show less
