Targeting a proteolytic neoepitope on CUB domain containing protein 1 (CDCP1) for RAS-driven cancers

• Published in: The Journal of clinical investigation Vol. 132; no. 4
• Main Authors: Lim, Shion A, Zhou, Jie, Martinko, Alexander J, Wang, Yung-Hua, Filippova, Ekaterina V, Steri, Veronica, Wang, Donghui, Remesh, Soumya G, Liu, Jia, Hann, Byron, Kossiakoff, Anthony A, Evans, Michael J, Leung, Kevin K, Wells, James A
• Format: Journal Article
• Language: English
• Published: United States American Society for Clinical Investigation 15.02.2022
• Subjects: Animals; antigen; Antigens, Neoplasm - genetics; Antigens, Neoplasm - immunology; BASIC BIOLOGICAL SCIENCES; Cancer; cancer immunotherapy; Carcinogenesis; Cell Adhesion Molecules - genetics; Cell Adhesion Molecules - immunology; Cell Line, Tumor; Epitopes - genetics; Epitopes - immunology; Gene expression; Genetic aspects; Health aspects; Humans; Male; Membrane proteins; Mice; Mice, Nude; Neoplasm Proteins - genetics; Neoplasm Proteins - immunology; Neoplasms, Experimental - genetics; Neoplasms, Experimental - immunology; Oncology, Experimental; Pancreatic Neoplasms - genetics; Pancreatic Neoplasms - immunology; Proteases; Proteolysis; Therapeutics; United States; Antigen; Cancer immunotherapy; Proteases; Therapeutics
• ISSN: 1558-8238; 0021-9738; 1558-8238
• DOI: 10.1172/JCI154604

Extracellular proteolysis is frequently dysregulated in disease and can generate proteoforms with unique neoepitopes not found in healthy tissue. Here, we demonstrate that Abs that selectively recognize a proteolytic neoepitope on CUB domain containing protein 1 (CDCP1) could enable more effective and safer treatments for solid tumors. CDCP1 is highly overexpressed in RAS-driven cancers, and its ectodomain is cleaved by extracellular proteases. Biochemical, biophysical, and structural characterization revealed that the 2 cleaved fragments of CDCP1 remain tightly associated with minimal proteolysis-induced conformational change. Using differential phage display, we generated recombinant Abs that are exquisitely selective to cleaved CDCP1 with no detectable binding to the uncleaved form. These Abs potently targeted cleaved CDCP1-expressing cancer cells as an Ab-drug conjugate, an Ab-radionuclide conjugate, and a bispecific T cell engager. In a syngeneic pancreatic tumor model, these cleaved-specific Abs showed tumor-specific localization and antitumor activity with superior safety profiles compared with a pan-CDCP1 approach. Targeting proteolytic neoepitopes could provide an orthogonal "AND" gate for improving the therapeutic index.