Identification by Differential Display of IL-24 Autocrine Loop Activated by Ras Oncogenes

Ras signaling pathway is thought to control the expression of a subset of yet-to-be-defined genes that are crucial for cell growth and differentiation. Here we have identified by differential display a novel oncogenic Ras target gene encoding a new cytokine. Biochemical studies reveal that this cytokine, which we named IL-24, is a member of IL-10 family of cytokines, and it signals through two hetorodimeric receptors, whose expression is also upregulated by ras oncogenes. Thus, IL-24 and its receptors may represent a novel autocrine loop coordinately activated by ras oncogenes.