Abstract 4295: High-throughput screening of osteosarcoma progression: A zebrafish model

Abstract Background: Osteosarcoma is the most common primary malignant bone tumour of non-hematologic origin. The survival of the patients has reached a plateau phase partly due to a poor understanding of osteosarcoma tumorigenesis. Previously we identified murine mesenchymal stem cells (mMSCs) that formed aggressive osteosarcoma-like lesions after injection in mice (Mohseny et al. J Pathol. 2009 Nov;219(3):294-305). In the current study we aimed to set up a high-throughput model to confirm the mMSCs transformation and to investigate further progression of these cells in vivo. Methods: The mMSCs were isolated from the bone marrow of C57BL/6 as well as BALB/c mice and cultured for 8 months. Cells of early and late passages were labeled with a fluorescent dye (CM- Dil) and injected into the yolk sacs of 2-days old transgenic zebrafish embryos with GFP labeled vascular system. The embryos were subjected to live imaging for 3 days to screen for cell homing, proliferation, migration and angiogenesis. Subsequently genome wide mRNA expression analysis for both zebrafish and mouse transcripts was performed. Results: The mMSCs were confirmed to transform in vitro after a period of crisis. High passage mMSCs, i.e. after the transformation, could proliferate, migrate into the fish body and induce angiogenesis whereas low passage MSCs, i.e. prior to transformation, did not. The microarray expression study was technically feasible as mouse transcripts from injected cells were detectable among the more abundant zebrafish RNA. Conclusions: The present study corroborates mMSCs transformation during long-term in vitro culturing. Furthermore it provides an efficient zebrafish model for studying mMSCs tumourigenic progression to characterize clinical relevant processes like migration and angiogenesis. After analyzing both mMSCs and zebrafish embryos on gene-expression level, the differential behavior of normal and transformed mMSCs as well as the host response can provide new insights into osteosarcoma progression. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4295. doi:10.1158/1538-7445.AM2011-4295