The Interleukin-11 Receptor α as a Candidate Ligand-Directed Target in Osteosarcoma: Consistent Data from Cell Lines, Orthotopic Models, and Human Tumor Samples

The interleukin-11 receptor α (IL-11Rα) is a functional target in bone metastasis. However, its role in primary bone tumors has not been established. As such, here, we evaluated IL-11Rα as a candidate target in primary and metastatic human osteosarcoma. First, in an orthotopic mouse model, we showed that IL-11Rα protein is markedly expressed in primary osseus and pulmonary metastatic osteosarcoma but absent from control normal tibia and lung. Moreover, systemic administration of an IL-11Rα–targeting phage displaying the cyclic nonapeptide CGRRAGGSC resulted in strong and selective accumulation of IL-11Rα–homing phage particles in the osteosarcoma but not in several control organs. Finally, IL-11Rα expression in a large panel of human primary and metastatic osteosarcoma samples was remarkably consistent with the observations in the orthotopic mouse model. These data establish IL-11Rα as a candidate target in human osteosarcoma and provide leads for the development of novel imaging and therapeutic agents for the management of this malignant tumor. [Cancer Res 2009;69(5):1995–9]