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.

Self-stabilized, hydrophobic or PEGylated paclitaxel polymer prodrug nanoparticles for cancer therapy

“…15 Polymer prodrugs indeed exhibit numerous advantages over traditional drug-loaded nanocarrier including absence of "burst release" (that is, the quick release post-administration of a significant fraction of the drug only adsorbed at the surface of the nanoparticles), enhanced drug loadings and drug solubility improvement. 16 The most extensively used strategy to produce Ptx-polymer prodrugs consists in the linkage of Ptx by post-functionalization to preformed polymers ("grafting to" method), such as polyethylene glycol (PEG), 17 poly(L-glutamic acid) (PGA), 18 polylactide (PLA), 19,20 dendrimer, 21,22 and other block polymers. [23][24][25] However, moderate conjugation efficacies, tedious multistep synthetic pathways and difficulty to accurately position the drug on the polymer chain were often witnessed.…”

Advancing Aptamers as Molecular Probes for Cancer Theranostic Applications—The Role of Molecular Dynamics Simulation

“…The experimental results indicated a strong affinity binding of h173‐Cy5.5 with high targeting specificity. Another research study reported the efficacy of a dual‐labelled fluorescent antibody‐drug conjugates (ADCs) for in vivo targeting of carcinoembryonic antigen (CEA) biomarker on positive pancreatic tumor cells (BxPC‐3) with high cytotoxicity and internalization kinetics . Research investigation by Keyaerts and team (2016) focused on generating a Ga‐HER2 (human epidermal growth factor receptor 2)‐nanobody as a molecular imaging probe for the diagnosis of breast cancers .…”

“…developed a dual‐labeled fluorescent antibody‐drug conjugate using a near‐infrared PEGylated fluorophore and theranostic antibody to specifically target pancreatic tumor cells for molecular imaging and targeted therapy. Research findings based on this technology displayed high cytotoxicity and effective internalization kinetics of the targeted BxPC‐3 pancreatic tumor cell line, indicating the effective performance of the dual‐labeled and bi‐functional fluorescent antibody‐drug complex in diagnosing, monitoring, and treating tumor cells simultaneously . Besides that, semiconductor quantum dots (QDs), which are luminescent materials with tunable optical and electrical features as well as fluorescence emission properties, are also gaining considerable attention in biological and chemosensory applications.…”

Correlation Between Preoperative Serum Carcinoembryonic Antigen Levels and Expression on Pancreatic and Rectal Cancer Tissue

“…In addition to the rapidly expanding field of CEA-targeted anticancer therapeutics, several imaging agents have become available for clinical testing. These agents can be labeled with radioisotopes for positron emission tomography or single-photon emission computed tomography imaging,10,11 with near-infrared (NIR) fluorescent dyes,12,13 or they can provide both molecular imaging and targeted therapy of CEA-expressing tumors 14…”