title: Development and Evaluation of a Fluorescent Antibody-Drug Conjugate for Molecular Imaging and Targeted Therapy of Pancreatic Cancer.
abstract: Antibodies are widely available and cost-effective research tools in life science, and antibody conjugates are now extensively used for targeted therapy, immunohistochemical staining, or in vivo diagnostic imaging of cancer. Significant advances in site-specific antibody labeling technologies have enabled the production of highly characterized and homogenous conjugates for biomedical purposes, and some recent studies have utilized site-specific labeling to synthesize bifunctional antibody conjugates with both imaging and drug delivery properties. While these advances are important for the clinical safety and efficacy of such biologics, these techniques can also be difficult, expensive, and time-consuming. Furthermore, antibody-drug conjugates (ADCs) used for tumor treatment generally remain distinct from conjugates used for diagnosis. Thus, there exists a need to develop simple dual-labeling methods for efficient therapeutic and diagnostic evaluation of antibody conjugates in pre-clinical model systems. Here, we present a rapid and simple method utilizing commercially available reagents for synthesizing a dual-labeled fluorescent ADC. Further, we demonstrate the fluorescent ADC's utility for simultaneous targeted therapy and molecular imaging of cancer both in vitro and in vivo. Employing non-site-specific, amine-reactive chemistry, our novel biopharmaceutical theranostic is a monoclonal antibody specific for a carcinoembryonic antigen (CEA) biomarker conjugated to both paclitaxel and a near-infrared (NIR), polyethylene glycol modified (PEGylated) fluorophore (DyLight™ 680-4xPEG). Using in vitro systems, we demonstrate that this fluorescent ADC selectively binds a CEA-positive pancreatic cancer cell line (BxPC-3) in immunofluorescent staining and flow cytometry, exhibits efficient internalization kinetics, and is cytotoxic. Model studies using a xenograft of BxPC-3 cells in athymic mice also show the fluorescent ADC's efficacy in detecting tumors in vivo and inhibiting tumor growth more effectively than equimolar amounts of unconjugated drug. Overall, our results demonstrate that non-selective, amine-targeting chemistry is an effective dual-labeling method for synthesizing and evaluating a bifunctional fluorescent antibody-drug conjugate, allowing concurrent detection, monitoring and treatment of cancer.
authors.affiliation: Department of Research and Development, Thermo Fisher Scientific, Rockford, Illinois, United States of America.|Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, Illinois, United States of America.
authors.forename: Steve
authors.initials: S
authors.lastname: Knutson
authors.affiliation: Department of Research and Development, Thermo Fisher Scientific, Rockford, Illinois, United States of America.
authors.forename: Erum
authors.initials: E
authors.lastname: Raja
authors.affiliation: Department of Research and Development, Thermo Fisher Scientific, Rockford, Illinois, United States of America.
authors.forename: Ryan
authors.initials: R
authors.lastname: Bomgarden
authors.affiliation: Department of Research and Development, Thermo Fisher Scientific, Rockford, Illinois, United States of America.
authors.forename: Marie
authors.initials: M
authors.lastname: Nlend
authors.affiliation: Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, Illinois, United States of America.
authors.forename: Aoshuang
authors.initials: A
authors.lastname: Chen
authors.affiliation: Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, Illinois, United States of America.
authors.forename: Ramaswamy
authors.initials: R
authors.lastname: Kalyanasundaram
authors.affiliation: Department of Research and Development, Thermo Fisher Scientific, Rockford, Illinois, United States of America.
authors.forename: Surbhi
authors.initials: S
authors.lastname: Desai
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D002272:Carcinoembryonic Antigen / Q000276:immunology; D045744:Cell Line, Tumor; D016503:Drug Delivery Systems; D005456:Fluorescent Dyes / Q000008:administration & dosage* / Q000627:therapeutic use; D006801:Humans; D018796:Immunoconjugates / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D017239:Paclitaxel / Q000008:administration & dosage* / Q000627:therapeutic use; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D002272:Carcinoembryonic Antigen; D005456:Fluorescent Dyes; D018796:Immunoconjugates; D017239:Paclitaxel