Phosphotyrosine picked threonine kinase stimulates proliferation of human osteosarcoma cells in vitro and in vivo

INTRODUCTION: Osteosarcoma (OS) is the most common primary bone tumor, and the main affected population is adolescents. The survival of OS patients was 10–20% when surgery was used as a single treatment. There is less basic research on OS than other tumors, and we need more ways to improve the survival rate. Phosphotyrosine picked threonine kinase (TTK) has been widely reported as an oncogene in multiple types of cancers, and it is also known as a clinical therapeutic target. This study aims to assess TTK expression levels in human OS tissues and its link with the clinical characteristics of OS patients, and to evaluate the potential role in OS development. MATERIAL AND METHODS: Immunohistochemical (IHC) assays were conducted to detect the expression levels of TTK in a total of 74 OS tissues and the corresponding adjacent tissues. Furthermore, according to the staining intensity of TTK in tumor tissues, patients were divided into TTK high and low expression groups. The possible correlation between TTK expression levels and clinical features were analyzed, and the effects of TTK on OS cell proliferation were detected through colony formation and cell counting kit-8 (CCK8) assays. The effects of TTK on tumor growth were detected using an animal model. RESULTS: Phosphotyrosine picked threonine kinase was abnormally highly expressed in human OS tissues. Meanwhile, TTK was significantly correlated with the clinical characteristics such as tumor size (p = 0.004*) and clinical stage (p = 0.014*) of OS patients. Our results also revealed that the inhibition of TTK dramatically suppressed the proliferation of OS cells in vitro and blocked tumor growth in mice. CONCLUSIONS: We demonstrated the involvement of TTK in the development of OS, and therefore we suggest that TTK should be considered as a promising therapy target for OS.