Three new chondrosarcoma cell lines: one grade III conventional central chondrosarcoma and two dedifferentiated chondrosarcomas of bone

BackgroundChondrosarcoma is the second most common primary sarcoma of bone. High-grade conventional chondrosarcoma and dedifferentiated chondrosarcoma have a poor outcome. In pre-clinical research aiming at the identification of novel treatment targets, the need for representative cell lines and model systems is high, but availability is scarce.MethodsWe developed and characterized three cell lines, derived from conventional grade III chondrosarcoma (L835), and dedifferentiated chondrosarcoma (L2975 and L3252) of bone. Proliferation and migration were studied and we used COBRA-FISH and array-CGH for karyotyping and genotyping. Immunohistochemistry for p16 and p53 was performed as well as TP53 and IDH mutation analysis. Cells were injected into nude mice to establish their tumorigenic potential.ResultsWe show that the three cell lines have distinct migrative properties, L2975 had the highest migration rate and showed tumorigenic potential in mice. All cell lines showed chromosomal rearrangements with complex karyotypes and genotypic aberrations were conserved throughout late passaging of the cell lines. All cell lines showed loss of CDKN2A, while TP53 was wild type for exons 5–8. L835 has an IDH1 R132C mutation, L2975 an IDH2 R172W mutation and L3252 is IDH wild type.ConclusionsBased on the stable culturing properties of these cell lines and their genotypic profile resembling the original tumors, these cell lines should provide useful functional models to further characterize chondrosarcoma and to evaluate new treatment strategies

Characterization of a New Human Cell Line (CH-3573) Derived from a Grade II Chondrosarcoma with Matrix Production

Microscopic imaging and technolog

Agreement Between Different Methodologies for Non-Invasive p.T790M and EGFR Sensitizing Mutation Testing

Background. Tyrosine kinase inhibitors (TKIs) are the current standard of care for patients with advanced EGFR-mutant non-small cell lung cancer (NSCLC). However, most patients progressed within 1 to 2 years. The EGFR p.T790M mutation is the most common resistance mechanism to first and second generation EGFR TKIs. The identification of p.T790M mutation is of considerable clinical relevance as osimertinib has demonstrated clinical efficacy in this setting. Guidelines recommend testing for the p.T790M mutation in blood at relapse to TKIs, and re-biopsy only in case of a negative result. Several blood based methodologies for detection of EGFR mutations have been developed in the recent years. However, the number of comparison studies between platforms is very limited. Method. This is a multicenter, cross-sectional study (ClinicalTrials.gov Identifier: NCT03363139) performed by the Spanish Lung Cancer Group. Samples from 75 consecutive EGFR mutant NSCLC patients were collected at disease progression to first line TKI treatment. The presence of EGFR mutations in the cfDNA was evaluated in 39 samples by 7 methodologies, namely: Cobas® EGFR Mutation Test v2 (Roche Diagnostics), Therascreen EGFR Plasma RGQ PCR Kit (Qiagen), QuantStudio® 3D Digital PCR System (Thermofisher), a 5′-nuclease real-time PCR (TaqMan®) assay in presence of PNA, OncoBEAM EGFR (Sysmex Inostics), NGS with two different gene panels: Oncomine® (Thermofisher) and Lung Cancer Panel (Qiagen). The agreement between methodologies was assessed using the kappa coefficient (K) and its corresponding 95% confidence intervals (95% CI). For quantitative variables the concordance correlation coefficient (ccc) was used. Result. Complete results are available for 39 patients. Overall, the agreement between all methodologies for the detection of p.T790M mutation as well as the original EGFR sensitizing mutation was good (K=0.669; 95CI: 0.504-0.835 and K=0.750 95CI: 0.599-0.899 respectively). Remarkably, the agreement between FDA-approved methodologies for p.T790M detection was almost perfect (K=0.926; 95CI: 0.712-1) and good for the EGFR sensitizing mutations (K=0.657; 95CI: 0.417-0.902). Similarly, the agreement between NGS-based methodologies for the detection of p.T790M and the EGFR activating mutations was very high (K=0.843; 95CI: 0.567-1 and K=0.872 95CI: 0.595-1 respectively). Moreover, concordance between both technologies for p.T790M and EGFR sensitizing mutation mutant allele frequency was excellent (ccc=0.956; 95CI: 0.906-1 and ccc=0.980 95CI: 0.950-1 respectively). The proportion of samples that were positive for p.T790M detection varied from 28% (PCR based technologies) to 37% depending on the methodology. Conclusion. NGS and PCR-based methodologies show a good to excellent agreement for the detection of EGFR mutations, including the p.T790M. Our results support the use of liquid biopsies for non-invasive testing of clinically relevant mutations (Data from the whole cohort will be presented at the meeting)

Targeting survivin as a potential new treatment for chondrosarcoma of bone

Chondrosarcomas are malignant cartilage-forming bone tumors, which are intrinsically resistant to chemo- and radiotherapy, leaving surgical removal as the only curative treatment option. Therefore, our aim was to identify genes involved in chondrosarcoma cell survival that could serve as a target for therapy. siRNA screening for 51 apoptosis-related genes in JJ012 chondrosarcoma cells identified BIRC5, encoding survivin, as essential for chondrosarcoma survival. Using immunohistochemistry, nuclear as well as cytoplasmic survivin expression was analyzed in 207 chondrosarcomas of different subtypes. Nuclear survivin has been implicated in cell-cycle regulation while cytoplasmic localization is important for its anti-apoptotic function. RT–PCR was performed to determine expression of the most common survivin isoforms. Sensitivity to YM155, a survivin inhibitor currently in phase I/II clinical trial for other tumors, was examined in 10 chondrosarcoma cell lines using viability assay, apoptosis assay and cell-cycle analysis. Survivin expression was found in all chondrosarcoma patient samples. Higher expression of nuclear and cytoplasmic survivin was observed with increasing histological grade in central chondrosarcomas. Inhibition of survivin using YM155 showed that especially TP53 mutant cell lines were sensitive, but no caspase 3/7 or PARP cleavage was observed. Rather, YM155 treatment resulted in a block in S phase in two out of three chondrosarcoma cell lines, indicating that survivin is more involved in cell-cycle regulation than in apoptosis. Thus, survivin is important for chondrosarcoma survival and chondrosarcoma patients might benefit from survivin inhibition using YM155, for which TP53 mutational status can serve as a predictive biomarker

New chondrosarcoma cell lines and mouse models to study the link between chondrogenesis and chemoresistance

Chondrosarcomas are cartilage-forming, poorly vascularized tumors. They represent the second malignant primary bone tumor of adults after osteosarcoma, but in contrast to osteosarcoma they are resistant to chemotherapy and radiotherapy, surgical excision remaining the only therapeutic option. Few cell lines and animal models are available, and the mechanisms behind their chemoresistance remain largely unknown. Our goal was to establish new cell lines and animal cancer models from human chondrosarcoma biopsies to study their chemoresistance. Between 2007 and 2012, 10 chondrosarcoma biopsies were collected and used for cell culture and transplantation into nude mice. Only one transplanted biopsy and one injected cell line has engrafted successfully leading to conventional central high-grade chondrosarcoma similar to the original biopsies. In culture, two new stable cell lines were obtained, one from a dedifferentiated and one from a grade III conventional central chondrosarcoma biopsy. Their genetic characterization revealed triploid karyotypes, mutations in IDH1, IDH2, and TP53, deletion in CDKN2A and/or MDM2 amplification. These cell lines expressed mesenchymal membrane markers (CD44, 73, 90, 105) and were able to produce a hyaline cartilaginous matrix when cultured in chondrogenic three-dimensional (3D) pellets. Using a high-throughput quantitative RT-PCR approach, we observed that cell lines cultured in monolayer had lost expression of several genes implicated in cartilage development (COL2A1, COMP, ACAN) but restored their expression in 3D cultures. Chondrosarcoma cells in monolayer were sensitive to several conventional chemotherapeutic agents but became resistant to low doses of mafosfamide or doxorubicin when cultured in 3D pellets, in parallel with an altered nucleic accumulation of the drug. Our results indicate that the cartilaginous matrix produced by chondrosarcoma cells may impair diffusion of several drugs and thus contribute to chemoresistance. Therefore, 3D chondrogenic cell pellets constitute a more relevant model to study chondrosarcoma chemoresistance and may be a valuable alternative to animal experimentations