Oncogenic dependency on members of the TAM tyrosine kinase receptor family (TYRO3, AXL, MERTK) has been reported in several cancer types, but their role in bladder cancer has never been explored.
This review will focus on PtdSer as a cofactor required for stimulating TYRO3, AXL and MERTK - comprising the TAM family of receptor tyrosine kinases by their ligands Protein S (PROS1) and growth-arrest-specific 6 (GAS6) in inflammation and cancer.
AXL is a member of the TYRO3-AXL-MER family of receptor tyrosine kinases, and has been revealed to be an important mediator of epithelial-mesenchymal transition (EMT) in several types of cancer.
The optimal design of treatment strategies to maximize the clinical benefit of these AXL and MER targeting agents are discussed in relation to the different cancer types and the types of resistance encountered.
On the one hand, knock-out of MERTK results in age-dependent autoimmunity characterized by failure of apoptotic cell clearance, while on the other, MERTK overexpression in cancer drives classical oncogene pathways leading to cell transformation.