S35 - Innovative approaches to establish and characterize primary cultures: an ex vivo 3D system and the zebrafish model

Abstract

Background: Patient-derived specimens are an invaluable resource to study the heterogeneous biology and behavior of cancer cells, in particular in rare tumors as Soft Tissue Sarcomas, for which several subtypes exist, not all covered by the matched cell lines. However in vivo studies on primary cultures are often limited by the low amount of material available, while conventional in vitro systems might alter the cell features and behavior. Here we present data on primary dedifferentiated liposarcoma cells cultured on tridimensional collagen-based scaffolds and injected into the Zebrafish model as a proof of concept of the usefulness of these models in the study of patient-derived material. Methods: Primary dedifferentiated liposarcoma cells, isolated from surgical specimens, were characterized in vitro for their morphological features, sensitiveness to drugs and biomarker expression, and in vivo for their engraftment and invasiveness abilities. Cells were treated with trabectedin and with the standard combination of ifosfamide and epirubicin. Aggressiveness markers were assayed by qPCR. Cells were injected in the heart cavity of zebrafish embryos, monitoring the embryos daily. Results: The 3D culture resulted enriched in cancer cells compared to standard monolayer culture and best preserved liposarcoma-associated markers. 3D-enriched cells proved sensitive to drugs with percentages of survival not significantly different between epirubicin plus ifosfamide and trabectedin alone. Liposarcoma cells injected in the Zebrafish were capable of surviving in the heart cavity and in later stages were scattered throughout the implantation area showing local migratory and invasive abilities, and the successful engraftment of this patient-derived liposarcoma culture in this animal model. Conclusions: This work provide the proof of concept of the ability of 3D cultures to preserve the original phenotypes of ex vivo cells, and of the Zebrafish model to offer a versatile in vivo system for studies with limited material. The implementation of these models could foster translational research studies, both in terms of biomolecular analyses, drug screenings and aggressiveness assays. Finally, we demonstrated in vitro a similar efficacy of trabectidin respect to the conventional first line therapy epirubicin plus ifosfamide opening new horizons to better investigate the mechanism of action of these drugs and the treatment strategy of dedifferentiated liposarcomas.