Autotaxin (ATX) is a prometastatic 
enzyme initially isolated from the conditioned media of 
human melanoma cells that stimulates a myriad of biological activities including 
angiogenesis and the promotion of 
cell growth, survival, and differentiation through the production of 
lysophosphatidic acid (LPA). ATX increases the aggressiveness and invasiveness of transformed cells, and ATX levels directly correlate with tumor stage and grade in several human malignancies. To study the role of ATX in the 
pathogenesis of malignant 
melanoma, we developed antibodies and 
small molecule inhibitors against recombinant human 
protein. 
Immunohistochemistry of 
paraffin embedded human tissue demonstrates that ATX levels are markedly increased in human primary and 
metastatic melanoma relative to benign nevi. Chemical screens identified several 
small molecule inhibitors with binding constants 
ranging from nanomolar to low micromolar. 
Cell migration and invasion assays with 
melanoma cell lines demonstrate that ATX markedly stimulates 
melanoma cell migration and invasion, an effect suppressed by ATX inhibitors. The migratory 
phenotype can be rescued by the addition of ATX's enzymatic product, LPA, confirming that the observed inhibition is linked to suppression of LPA production by ATX. Chemical analogues of the inhibitors demonstrate structure activity relationships important for ATX inhibition and indicate pathways for their optimization. These studies suggest that ATX is an approachable molecular target for the 
rational design of chemotherapeutic agents directed against human malignancies driven by the ATX / LPA axis, especially including malignant melanoma, among numerous others including breast and ovarian cancers.