Osteosarcoma progression is associated with increased nuclear levels and transcriptional activity of activated β-Catenin.

Osteosarcoma (OS) is an aggressive primary bone malignancy that has peak incidence in children and young adults <25 years of age. Despite current multimodal treatments, no significant change in patient outcome has been observed in two decades. Presently, there is a lack of established, reliable baseline prognostic markers for aggressive OS, other than extent and site of disease involvement. The canonical Wnt/β-catenin pathway controls multiple cellular processes, and is known to be a critical pathway in OS progression. This pathway regulates cellular levels of β-catenin, which is a significant player in the oncogenesis and progression of many cancers. We investigated the relationship between β-catenin, more specifically, the transcriptionally active form of β-catenin, Activated β-Catenin (ABC), and OS progression. Using an in vitro model, we observed that cellular/nuclear ABC levels, but not cellular/nuclear β-catenin levels, increase with the degree of aggressiveness in OS. Our results demonstrate a strong association between nuclear-ABC levels and aggressive OS in vitro. Furthermore, we observed significant correlation between positive nuclear-ABC and patient age and tumor stage. Our results support the potential use of ABC as a predictive marker for risk stratification in OS.