Background: Mouse osteosarcoma cell-lines enabling in vivo studies in syngeneic mouse strains are rare but important for preclinical studies. Existing cell-lines when injected are mainly osteolytic with a moderate tumor osteoid tissue formation. There is a crucial need for new cell-lines with higher osteogenic characteristic.

Methods: A female osteoprotegerin null mutant mouse, breed in the animal house of the Faculty of Medicine from the University of Nantes (France), spontaneously developed an osteosarcoma on the left tibia. The mouse was sacrificed, a biopsy was place in culture for further in vitro and in vivo (injections) studies and the tumor was analyzed using μ-CT, μ-radiography, classical histology and immunohistochemistry.

Results: μ-CT and μ-radiography analyses evidenced that the tumor developed in the Opg-/- mouse was highly osteogenic with an important tumor osteoid tissue that colonized most of the surrounding soft tissues. A total destruction of the tibia was observed. Histology and immunohistochemistry confirmed the presence of an osteosarcoma with an important expression of most bone markers as Osterix. An important vascularization was evidenced in the tumor as the presence of numerous TRAP positive cells. Monocyte/macrophage and T-lymphocyte cells were also present in this tumor. From the biopsy a cell-line was obtained and named UMR957. This cell-line evidenced all markers of the osteoblast cell. When injected in the tibia vicinity of either naïve C57BL/6J, Nude or Opg-/- mouse a highly osteogenic osteosarcoma was observed with similar features to the initial tumor.

Conclusions: A new mouse osteosarcoma cell-line was obtained from a spontaneous tumor developed in an Opg-/- mouse. This cell-line when injected in syngeneic mouse recapitulates all features of the initial tumor more particularly its massive osteoid tissue formation.

Citation Format: Benjamin Navet, Jérome Amiaud, Céline Charrier, Thibaut Quillard, Bénédicte Brounais-Le Royer, Dominique Heymann, Frederic P.R. Lezot. UMR957: a new osteogenic osteosarcoma cell-line derived from an osteoprotegerin null mutant mouse. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4270.