Chimeric anti-podoplanin antibody suppresses tumor metastasis through neutralization and antibody-dependent cellular cytotoxicity.

Podoplanin is a platelet aggregation-inducing factor associated with tumor metastasis, malignant progression, and cancer stem cells. We produced a rat-human chimeric anti-podoplanin mAb, NZ-8, from rat anti-podoplanin mAb (NZ-1). Although both NZ-1 and NZ-8 possess high binding affinities and high neutralizing activities of platelet aggregation, the antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity of NZ-8 were much higher than NZ-1. Furthermore, both NZ-1 and NZ-8 inhibited the growth of podoplanin-expressing tumors in vivo. Both NZ-1 and NZ-8 also suppressed hematogenous metastasis of podoplanin-expressing tumors. These results suggest that anti-podoplanin mAbs suppressed hematogenous metastasis by both neutralization and antibody-dependent cellular cytotoxicity/complement-dependent cytotoxicity activities. Targeting therapy to podoplanin-expressing tumors should be useful as a novel immunotherapy.