PF-03732010: A Fully Human Monoclonal Antibody against P-Cadherin with Antitumor and Antimetastatic Activity

Purpose: P-cadherin is a membrane glycoprotein that functionally mediates tumor cell adhesion, proliferation, and invasiveness. We characterized the biological properties of PF-03732010, a human monoclonal antibody against P-cadherin, in cell-based assays and tumor models. Experimental Design: The affinity, selectivity, and cellular inhibitory activity of PF-03732010 were tested in vitro. Multiple orthotopic and metastatic tumor models were used for assessing the antitumor and antimetastatic activities of PF-03732010. Treatment-associated pharmacodynamic changes were also investigated. Results: PF-03732010 selectively inhibits P-cadherin-mediated cell adhesion and aggregation in vitro. In the P-cadherin-overexpressing tumor models, including MDA-MB-231-CDH3, 4T1-CDH3, MDA-MB-435HAL- CDH3, HCT116, H1650, PC3M-CDH3, and DU145, PF-03732010 inhibited the growth of primary tumors and metastatic progression, as determined by bioluminescence imaging. Computed tomography imaging, H&E stain, and quantitative PCR analysis confirmed the antimetastatic activity of PF-03732010. In contrast, PF-03732010 did not show antitumor and antimetastatic efficacy in the counterpart tumor models exhibiting low P-cadherin expression. Mechanistic studies via immunofluorescence, immunohistochemical analyses, and 3'-[F-18] fluoro-3'-deoxythymidine-positron emission tomography imaging revealed that PF-03732010 suppressed P-cadherin levels, caused degradation of membrane beta-catenin, and concurrently suppressed cytoplasmic vimentin, resulting in diminished metastatic capacity. Changes in the levels of Ki67, caspase-3, and 3'-[F-18] fluoro-3'-deoxythymidine tracer uptake also indicated antiproliferative activity and increased apoptosis in the tested xenografts. Conclusions: These findings suggest that interrupting the P-cadherin signaling pathway may be a novel therapeutic approach for cancer therapy. PF-03732010 is presently undergoing evaluation in Phase 1 clinical trials. Clin Cancer Res; 16(21); 5177-88. (C)2010 AACR.