A multi-faceted discovery strategy identifies functional Dickkopf-1 antibodies binding to cysteine-rich domain 1 of hDKK1 for cancer immunotherapy via Wnt non-canonical pathway 2061

Description Wnt signaling plays an important role in embryonic development and tumorigenesis. These biological effects can be exerted by activation of Wnt canonical or pathway or non-canonical pathway, and regulation of a set of downstream genes. DKK1 is a potent inhibitor of Wnt signaling via competing with Wnt binding to the LRP5/6 co-receptors. DKK1 is tumorigenic in multiple cancer types and immunosuppressive via MDSCs and NK cells. DKK1 has become a promising target for cancer immunotherapy. In this study, we created phage display libraries and machine learning models for optimal discovery. We discovered anti-DKK1 antibodies blocking the binding of DKK1 to the co-receptors. Binding of the antibodies to different cysteine-rich domains (CRDs) of hDKK1 leads to different activation effects. The in vitro functional assays showed the interaction of Wnt canonical pathway was restored in the presence of anti-DKK1 antibodies binding to DKK1 C-terminal CRD2, resulting in upregulating Wnt canonical TCF/LEF signaling and reactivating osteoblast differentiation. Moreover, anti-DKK1 antibodies binding to DKK1 N-terminal CRD1 induced Wnt non-canonical JNK phosphorylation, immune cell activation and led to tumor cell cytotoxicity. In vivo studies indicated that anti-DKK1 antibody leads are potent in tumor regression and may have promising efficacy as a cancer immunotherapy via activating Wnt non-canonical pathway. Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)