Chondrosarcoma and giant cell tumour of bone (GCTB) are bone tumours characterized by recurrent mutations (IDH1/IDH2 and H3F3A, respectively) that induce remodelling of the epigenetic landscape.... Show moreChondrosarcoma and giant cell tumour of bone (GCTB) are bone tumours characterized by recurrent mutations (IDH1/IDH2 and H3F3A, respectively) that induce remodelling of the epigenetic landscape. The standard of care for both of these sarcoma subtypes is surgery and alternative treatment options for patients with inoperable disease are currently lacking (chondrosarcoma) or suboptimal (GCTB). Therefore, the aim of this thesis was to identify novel therapeutic targets for high-grade chondrosarcoma as well as GCTB, with a focus on potential therapies that could counteract the remodelling of the epigenome. PARP and HDAC inhibition, alone or in combination treatment strategies, were identified as promising therapeutic strategies for chondrosarcoma or both of these bone tumours, respectively. Additionally, this thesis describes the development and use of novel 3D cell culture models which can be used to improve the translation of preclinical findings to the clinic. Show less
Aim: Follow-up strategies for high-grade bone sarcomas have been optimized to facilitate early detection of local recurrence and distant metastasis. The ideology is that early detection enables... Show moreAim: Follow-up strategies for high-grade bone sarcomas have been optimized to facilitate early detection of local recurrence and distant metastasis. The ideology is that early detection enables early treatment presuming better survival. However, the clinical value for each individual patient remains questionable. This study aims to evaluate oncological events after initial treatment in order to assess current follow-up strategies for high-grade bone sarcomas in the Netherlands.Patients and Methods: A retrospective cohort study was conducted based on a national registry. All cases were retrieved from the Netherlands Cancer Registry. Our study consisted of 393 patients treated between 2007 and 2011 with complete follow-up data. Baseline characteristics were analysed for all entities. Local recurrence and distant metastasis was analysed along with overall survival for high-grade chondrosarcoma, high-grade osteo-sarcoma, Ewing sarcoma and chordoma.Results: Median follow-up was 8,3 years for high-grade chondrosarcoma, 4,9 for high-grade osteosarcoma, 3,8 for Ewing sarcoma and 7,5 for chordoma. Median time to local recurrence and distant metastasis was 1,2 years for high-grade osteosarcoma and 1,5 years for Ewing sarcoma. For high-grade osteosarcoma with localized disease at presentation, 0.09 new distant metastatic events per patient per year were seen after five years of follow-up with 11,1 patients needed to follow-up for any event. Five-year overall survival was 60,0% for high-grade chon-drosarcoma, 50,0% for high-grade osteosarcoma, 45,3% for Ewing sarcoma and 71,4% for chordoma.Conclusions: This nationwide study shows a plateau in local recurrences and distant metastatic events after four years of treatment for patients with high-grade osteosarcoma and Ewing sarcoma. Due to a lack of reliable ev-idence however, we were not able to provide additional guidance on follow-up intervals and duration. Collab-orative research with larger groups is needed in order to provide a solid scientific recommendation for follow-up in the heterogenous patient population with bone sarcoma. Show less
The aim of this thesis is to determine diagnostic performance of machine learning in differentiating between atypical cartilaginous tumor (ACT) and high-grade chondrosarcoma (CS) based on radiomic... Show moreThe aim of this thesis is to determine diagnostic performance of machine learning in differentiating between atypical cartilaginous tumor (ACT) and high-grade chondrosarcoma (CS) based on radiomic features derived from magnetic resonance imaging (MRI) and computed tomography (CT). In chapter 2, the concept of radiomics of musculoskeletal sarcomas is introduced and a systematic review on radiomic feature reproducibility and validation strategies is conducted. In chapter 3, a preliminary study is performed to investigate the performance of MRI radiomics-based machine learning in discriminating ACT from high-grade CS, using a single-center cohort, in comparison with an expert radiologist. In chapter 4, the influence of interobserver segmentation variability on the reproducibility of CT and MRI radiomic features of cartilaginous bone tumors is assessed. In chapter 5, the performance of CT radiomics-based machine learning in discriminating ACT from high-grade CS of long bones is determined and validated using independent data from a multicenter cohort, compared to an expert radiologist. In chapter 6, the performance of MRI radiomics-based machine learning in differentiating between ACT and grade II CS of long bones is determined and validated using independent data from a multicenter cohort, in comparison with an expert radiologist. Finally, in chapter 7, the main results and implications of this thesis are summarized and discussed. Show less
Kroesen, M.; Miladinovic, V.; Hutschemaekers, S.A.J.; Jacobs, J.; Vos, C. van der; Wolf, A.L.; ... ; Krol, A.D.G. 2022
Background: Due to its specific physical characteristics, proton irradiation is especially suited for irradiation of chordomas and chondrosarcoma in the axial skeleton. Robust plan optimization... Show moreBackground: Due to its specific physical characteristics, proton irradiation is especially suited for irradiation of chordomas and chondrosarcoma in the axial skeleton. Robust plan optimization renders the proton beam therapy more predictable upon individual setup errors. Reported experience with the planning and delivery of robustly optimized plans in chordoma and chondrosarcoma of the mobile spine and sacrum, is limited. In this study, we report on the clinical use of robustly optimized, intensity modulated proton beam therapy in these patients.Methods: We retrospectively reviewed patient, treatment and acute toxicity data of all patients with chordoma and chondrosarcoma of the mobile spine and sacrum, treated between 1 April 2019 and 1 April 2020 at our institute. Anatomy changes during treatment were evaluated by weekly cone-beam CTs (CBCT), supplemented by scheduled control-CTs or ad-hoc control-CTs. Acute toxicity was scored weekly during treatment and at 3 months after therapy according to CTCAE 4.0.Results: 17 chordoma and 3 chondrosarcoma patients were included. Coverage of the high dose clinical target volume was 99.8% (range 56.1-100%) in the nominal and 80.9% (range 14.3-99.6%) in the voxel-wise minimum dose distribution. Treatment plan adaptation was needed in 5 out of 22 (22.7%) plans. Reasons for plan adaptation were either reduced tumor coverage or increased dose to the OAR.Conclusions: Robustly optimized intensity modulated proton beam therapy for chordoma and chondrosarcoma of the mobile spine is feasible. Plan adaptations due to anatomical changes were required in approximately 23 percent of treatment courses. (C) 2021 The Authors. Published by Elsevier B.V. Show less
Chondrosarcoma is the second most common primary bone malignancy, representing one fourth of all primary bone sarcomas. It is typically resistant to radiation and chemotherapy treatments. However,... Show moreChondrosarcoma is the second most common primary bone malignancy, representing one fourth of all primary bone sarcomas. It is typically resistant to radiation and chemotherapy treatments. However, the molecular mechanisms that contribute to cancer aggressiveness in chondrosarcomas remain poorly characterized. Here, we studied the role of mitochondrial transporters in chondrosarcoma aggressiveness including chemotherapy resistance. Histological grade along with stage are the most important prognostic biomarkers in chondrosarcoma. We found that high-grade human chondrosarcoma tumors have higher expression of the mitochondrial protein, translocase of the outer mitochondrial membrane complex subunit 20 (TOMM20), compared to low-grade tumors. TOMM20 overexpression in human chondrosarcoma cells induces chondrosarcoma tumor growth in vivo. TOMM20 drives proliferation, resistance to apoptosis and chemotherapy resistance. Also, TOMM20 induces markers of epithelial to mesenchymal transition (EMT) and metabolic reprogramming in these mesenchymal tumors. In conclusion, TOMM20 drives chondrosarcoma aggressiveness and resistance to chemotherapy. Show less
Chondrosarcomas are malignant cartilage producing tumours, occurring mostly around the age of fifty. Treatment is mainly by surgery, since tumours are relatively resistant toward chemo-and... Show moreChondrosarcomas are malignant cartilage producing tumours, occurring mostly around the age of fifty. Treatment is mainly by surgery, since tumours are relatively resistant toward chemo-and radiotherapy. This means that patients with inoperable disease have no alternative treatment options. In this thesis we describe the use of compound and siRNA screens to identify new targeted treatment options for patients with chondrosarcoma. Using available chondrosarcoma cell lines as a model we investigated apoptotic proteins, kinases and metabolic regulators in a non-biased way to identify most promising hits. In addition the role of individual Bcl-2 family members Bcl-2, Bcl-xl and Bcl-w was investigated. Results reveal a role for Bcl-2 family member Bcl-xl, anti-apoptotic and cell cycle regulator Survivin, cell cycle regulators AURKA, CHK1 and PLK1 and mTOR as important survival proteins in chondrosarcoma. Moreover treatment with Bcl-xl or CHK1 inhibitors could chemo-sensitize a subset of chondrosarcoma cell lines. Furthermore alterations in the Rb1 pathway have been identified as a marker for radio resistance in chondrosarcoma patient samples. Collectively these studies identify several lead targets that might be useful as targeted treatment options for chondrosarcoma patients. Future research should focus more on the therapeutic value of these targets, and translate these pre-clinical findings to clinical practise. Show less
Chondrosarcomas are malignant cartilage tumors that are relatively resistant towards conventional therapeuticapproaches. Kinase inhibitors have been investigated and shown successful for several... Show moreChondrosarcomas are malignant cartilage tumors that are relatively resistant towards conventional therapeuticapproaches. Kinase inhibitors have been investigated and shown successful for several different cancer types. Inthis study we aimed at identifying kinase inhibitors that inhibit the survival of chondrosarcoma cells and therebyserve as new potential therapeutic strategies to treat chondrosarcoma patients.An siRNA screen targeting 779 different kinases was conducted in JJ012 chondrosarcoma cells in parallelwith a compound screen consisting of 273 kinase inhibitors in JJ012, SW1353 and CH2879 chondrosarcoma celllines. AURKA, CHK1 and PLK1 were identified as most promising targets and validated further in a morecomprehensive panel of chondrosarcoma cell lines. Dose response curves were performed using tyrosine kinaseinhibitors: MK-5108 (AURKA), LY2603618 (CHK1) and Volasertib (PLK1) using viability assays and cell cycleanalysis. Apoptosis was measured at 24 h after treatment using a caspase 3/7 assay. Finally, chondrosarcomapatient samples (N = =34) were used to examine the correlation between AURKA, CHK1 and PLK1 RNAexpression and documented patient survival.Dose dependent decreases in viability were observed in chondrosarcoma cell lines after treatment with MK-5108, LY2603618 and volasertib, with cell lines showing highest sensitivity to PLK1 inhibition. In additionincreased sensitivity to conventional chemotherapy was observed after CHK1 inhibition in a subset of the celllines. Interestingly, whereas AURKA and CHK1 were both expressed in chondrosarcoma patient samples, PLK1expression was found to be low compared to normal cartilage. Analysis of patient samples revealed that highCHK1 RNA expression correlated with a worse overall survival.AURKA, CHK1 and PLK1 are identified as important survival genes in chondrosarcoma cell lines. Althoughfurther research is needed to validate these findings, inhibiting CHK1 seems to be the most promising potentialtherapeutic target for patients with chondrosarcoma. Show less
Chondrosarcomas are chemo- and radiotherapy resistant and frequently harbor mutationsin isocitrate dehydrogenase (IDH1 or IDH2), causing increased levels of D-2-hydroxyglutarate(D-2-HG). DNA repair... Show moreChondrosarcomas are chemo- and radiotherapy resistant and frequently harbor mutationsin isocitrate dehydrogenase (IDH1 or IDH2), causing increased levels of D-2-hydroxyglutarate(D-2-HG). DNA repair defects and synthetic lethality with poly(ADP-ribose) polymerase (PARP)inhibition occur in IDH mutant glioma and leukemia models. Here we evaluated DNA repairand PARP inhibition, alone or combined with chemo- or radiotherapy, in chondrosarcoma celllines with or without endogenous IDH mutations. Chondrosarcoma cell lines treated with thePARP inhibitor talazoparib were examined for dose–response relationships, as well as underlyingcell death mechanisms and DNA repair functionality. Talazoparib was combined with chemo- orradiotherapy to evaluate potential synergy. Cell lines treated long termwith an inhibitor normalizingD-2-HG levels were investigated for synthetic lethality with talazoparib. We report that talazoparibsensitivity was variable and irrespective of IDH mutation status. All cell lines expressed AtaxiaTelangiectasia Mutated (ATM), but a subset was impaired in poly(ADP-ribosyl)ation (PARylation)capacity, homologous recombination, andO-6-methylguanine-DNAmethyltransferase (MGMT) expression.Talazoparib synergized with temozolomide or radiation, independent of IDH1 mutant inhibition.This study suggests that talazoparib combined with temozolomide or radiation are promisingtherapeutic strategies for chondrosarcoma, irrespective of IDH mutation status. A subset ofchondrosarcomas may be deficient in nonclassical DNA repair pathways, suggesting that PARPinhibitor sensitivity is multifactorial in chondrosarcoma. Show less
Chondrosarcomas are malignant cartilage tumors that are relatively resistant towards conventional therapeutic approaches. Kinase inhibitors have been investigated and shown successful for several... Show moreChondrosarcomas are malignant cartilage tumors that are relatively resistant towards conventional therapeutic approaches. Kinase inhibitors have been investigated and shown successful for several different cancer types. In this study we aimed at identifying kinase inhibitors that inhibit the survival of chondrosarcoma cells and thereby serve as new potential therapeutic strategies to treat chondrosarcoma patients.An siRNA screen targeting 779 different kinases was conducted in JJ012 chondrosarcoma cells in parallel with a compound screen consisting of 273 kinase inhibitors in JJ012, SW1353 and CH2879 chondrosarcoma cell lines. AURKA, CHK1 and PLK1 were identified as most promising targets and validated further in a more comprehensive panel of chondrosarcoma cell lines. Dose response curves were performed using tyrosine kinase inhibitors: MK-5108 (AURKA), LY2603618 (CHK1) and Volasertib (PLK1) using viability assays and cell cycle analysis. Apoptosis was measured at 24 h after treatment using a caspase 3/7 assay. Finally, chondrosarcoma patient samples (N = = 34) were used to examine the correlation between AURKA, CHK1 and PLK1 RNA expression and documented patient survival.Dose dependent decreases in viability were observed in chondrosarcoma cell lines after treatment with MK-5108, LY2603618 and volasertib, with cell lines showing highest sensitivity to PLK1 inhibition. In addition increased sensitivity to conventional chemotherapy was observed after CHK1 inhibition in a subset of the cell lines. Interestingly, whereas AURKA and CHK1 were both expressed in chondrosarcoma patient samples, PLK1 expression was found to be low compared to normal cartilage. Analysis of patient samples revealed that high CHK1 RNA expression correlated with a worse overall survival.AURKA, CHK1 and PLK1 are identified as important survival genes in chondrosarcoma cell lines. Although further research is needed to validate these findings, inhibiting CHK1 seems to be the most promising potential therapeutic target for patients with chondrosarcoma. Show less
Ewing and chondrosaroma are two forms of primary bone cancer. The few clinical studies that are published in recent decades show disappointing results. With a 5 year survival of 10% for inoperable... Show moreEwing and chondrosaroma are two forms of primary bone cancer. The few clinical studies that are published in recent decades show disappointing results. With a 5 year survival of 10% for inoperable Ewing sarcoma and 2% for inoperable chondrosarcoma patients the outcome is poor. If a patient has not responded to standard treatment, they are often treated with combinations based on expert opinion of the treating physician. These treatment combinations have not been investigated in studies because of the small patient numbers which makes starting a study very difficult and time-consuming. One combination is of the chemotherapeutic agents etoposide with carboplatin or cisplatin. Analysis of the survival data of patients treated with these combinations shows that they are comparable to other standard treatment options. New non-chemotherapy treatment options are currently being investigated. Examples are the IGF-1R and PARP route. The current knowledge of both routes shows that disregulation causes malignant transformation and / or disease progression. Inhibition of these routes is therefore a possible treatment. In clinical studies, the results are not positive for all patients. This is due to incorrect patient selection and not being tested in combination with already used treatments. Show less
Aims: Chondrosarcoma, osteosarcoma and Ewing sarcoma form the majority of malignant primary tumours of bone. High-grade bone sarcomas require intensive treatment due to their rapid and invasive... Show moreAims: Chondrosarcoma, osteosarcoma and Ewing sarcoma form the majority of malignant primary tumours of bone. High-grade bone sarcomas require intensive treatment due to their rapid and invasive growth pattern and metastasising capabilities. This nationwide study covers overall incidence, treatment and survival patterns of bone sarcomas in a 15-year period (2000-2014) in the total population of the Netherlands.Patients and methods: Data for this study were derived from the Netherlands Cancer Registry, which receives primary notification from the national pathology database. Classification and categorisation was based on the ICD-O-3 classification and the WHO classification 2013 applied according to our clinicopathological expertise. Overall incidence over the 15-year-period was calculated as a rate per 100,000 person-years (using the European Standardised Rate, ESR). Survival was analysed with Kaplan-Meier curves and Cox proportional hazards regression.Results: Incidence for high-grade chondrosarcoma (n = 429) was estimated at 0.15 per 100,000 ESR, and 5-year overall survival at 65.9% (95% confidence interval (CI): 61.0%-70.4%). Incidence for high-grade central osteosarcoma (n = 605) was estimated at 0.25 per 100,000 ESR and 5-year survival at 53.9% (95% CI: 49.7%-58.0%). Ewing sarcoma incidence (n = 334) was estimated at 0.15 per 100,000 ESR and 5-year survival at 59.3% (95% CI: 53.5%-64.6%). For high-grade central osteosarcoma, treatment at a bone tumour centre was associated with better survival (HR 0.593).Conclusions: This study provides comprehensive incidence estimates for all the main primary bone sarcomas over a 15-year time period in a Northern European country with little migration. Centralisation of bone sarcoma care improves the clinical outcome in osteosarcoma. Show less
Jong, Y. de; Ingola, M.; Briaire-de Bruijn, I.H.; Kruisselbrink, A.B.; Venneker, S.; Palubeckaite, I.; ... ; Bovee, J.V.M.G. 2019
Thesis explored potential new therapeutic strategies by identifying cellular pathways that are essential for chondrosarcoma and osteosarcoma cell survival. Although clinical trials with IGF1R... Show moreThesis explored potential new therapeutic strategies by identifying cellular pathways that are essential for chondrosarcoma and osteosarcoma cell survival. Although clinical trials with IGF1R inhibitors have disappointing results in osteosarcoma, this thesis strengthens the view that the IGF pathway can be an effective target for osteosarcoma therapy if an appropriate selection of patients is treated with IGF1R/IR dual inhibitors. When optimized clinical trials targeting the IGF pathway will be performed in the future, chondrosarcoma patients should not be recruited, as there is limited preclinical rationale for the efficacy of IGF1R targeting agents in chondrosarcoma. We identified two promising pathways that can be used to target chondrosarcoma; the NAD+ synthesis pathway and glutaminolysis. Our results suggest that chondrosarcoma patients should be included in future studies with drugs that interfere in these pathways, regardless of their IDH1/2 mutation status. Show less
Background Chondrosarcoma is a malignant cartilage forming bone tumour for which no effective systemic treatment is available. Previous studies illustrate the need for a better understanding of... Show moreBackground Chondrosarcoma is a malignant cartilage forming bone tumour for which no effective systemic treatment is available. Previous studies illustrate the need for a better understanding of the role of the IGF pathway in chondrosarcoma to determine if it can be a target for therapy, which was therefore explored in this study. Methods Expression of mediators of IGF1R signalling and phosphorylation status of IRS1 was determined in chondrosarcoma cell lines by qRT-PCR and western blot. The effect of activation and inhibition of IGF1R signalling on downstream targets was assessed by western blot. Ten chondrosarcoma cell lines were treated with OSI-906 (IGF1R and IR dual inhibitor) after which cell proliferation and migration were determined by a viability assay and the xCELLigence system, respectively. In addition, four chondrosarcoma cell lines were treated with a combination of doxorubicin and OSI-906. By immunohistochemistry, IGF1R expression levels were determined in tissue microarrays of 187 cartilage tumours and ten paraffin embedded cell lines. Results Mediators of IGF1R signalling are heterogeneously expressed and phosphorylated IRS1 was detected in 67 % of the tested chondrosarcoma cell lines, suggesting that IGF1R signalling is active in a subset of chondrosarcoma cell lines. In the cell lines with phosphorylated IRS1, inhibition of IGF1R signalling decreased phosphorylated Akt levels and increased IGF1R expression, but it did not influence MAPK or S6 activity. In line with these findings, treatment with IGF1R/IR inhibitors did not impact proliferation or migration in any of the chondrosarcoma cell lines, even upon stimulation with IGF1. Although synergistic effects of IGF1R/IR inhibition with doxorubicin are described for other cancers, our results demonstrate that this was not the case for chondrosarcoma. In addition, we found minimal IGF1R expression in primary tumours in contrast to the high expression detected in chondrosarcoma cell lines, even if both were derived from the same tumour, suggesting that in vitro culturing upregulates IGF1R expression. Conclusions The results from this study indicate that the IGF pathway is not essential for chondrosarcoma growth, migration or chemoresistance. Furthermore, IGF1R is only minimally expressed in chondrosarcoma primary tumours. Therefore, the IGF pathway is not expected to be an effective therapeutic target for chondrosarcoma of bone. Show less
