Definition

An orally bioavailable inhibitor of the receptor tyrosine kinase AXL (UFO), with potential immunostimulating and antineoplastic activities. Upon oral administration, AXL inhibitor AB801 targets, reversibly binds to, and prevents the activation of AXL. This blocks AXL-mediated signal transduction pathways, and inhibits both AXL-mediated tumor cell growth, proliferation and migration and AXL-mediated immunosuppression. AXL, a member of the Tyro3, AXL and Mer (TAM) family of receptor tyrosine kinases, is overexpressed by many tumor cell types and expressed in a variety of immune cells including macrophages, natural killer (NK) cells, and regulatory T cells (Tregs). It plays a key role in tumor cell proliferation, survival, invasion, and metastasis, and is a mediator of immunosuppression. Its expression is associated with drug resistance and poor prognosis.