Demonstration of receptors for a PDGF-like mitogen on human osteosarcoma cells.

U-2 OS human osteosarcoma cells synthesize, process and secrete a platelet-derived growth factor (PDGF)-like mitogen. Incubation of these cells with 1 mM suramin unmasks PDGF receptor sites which are normally occupied or down regulated by the secreted endogenous PDGF-like mitogen. Partially purified preparations of metabolically labelled U-2 OS conditioned medium binds to U-2 OS cells and binding is inhibited by excess PDGF. These findings suggest that U-2 OS cells are capable of autocrine stimulation.