1. An engineered anti-CA19-9 cys-diabody for positron emission tomography imaging of pancreatic cancer and targeting of polymerized liposomal nanoparticles
- Author
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Girgis, Mark D, Federman, Noah, Rochefort, Matthew M, McCabe, Katelyn E, Wu, Anna M, Nagy, Jon O, Denny, Christopher, and Tomlinson, James S
- Subjects
Rare Diseases ,Nanotechnology ,Cancer ,Biomedical Imaging ,Biotechnology ,Pancreatic Cancer ,Digestive Diseases ,Bioengineering ,Animals ,Antibodies ,Bispecific ,CA-19-9 Antigen ,Cell Line ,Tumor ,Cystine ,Female ,Humans ,Immunotherapy ,Liposomes ,Mice ,Mice ,Nude ,Multiple Myeloma ,Nanoparticles ,Pancreatic Neoplasms ,Positron-Emission Tomography ,Protein Engineering ,Single-Chain Antibodies ,Xenograft Model Antitumor Assays ,Antibody ,CA19-9 ,Imaging ,Nanoparticle ,Pancreatic cancer ,Clinical Sciences ,Surgery - Abstract
BackgroundAntibody-based therapeutics is a rapidly growing field. Small engineered antibody fragments demonstrate similar antigen affinity compared with the parental antibody but have a shorter serum half-life and possess the ability to be conjugated to nanoparticles. The goal of this study was to engineer an anti-carbohydrate antigen 19-9 (CA19-9) cys-diabody fragment in hopes of targeting nanoparticles to pancreatic cancer.MethodsThe anti-CA19-9 cys-diabody was created by engineering a C-terminal cysteine residue into the DNA single-chain Fv construct of the anti-CA19-9 diabody and expressed in NS0 cells. Maleimide chemistry was used to conjugate the cys-diabody to polymerized liposomal nanoparticles (PLNs) through the cysteine residues. Flow cytometry was used to evaluate targeting of cys-diabody and cys-diabody-PLN conjugate to human pancreatic cancer cell lines. The cys-diabody was radiolabeled with a positron emitter ((124)I) and evaluated in a mouse model of CA19-9-positive and CA19-9-negative xenografts with micro-positron emission tomography/micro-computed tomography at successive time intervals after injection. Percentage of injected dose per gram of radioactivity was measured in blood and tumor to provide objective confirmation of the micro-positron emission tomographic images.ResultsTumor xenograft imaging of the anti-CA19-9 cys-diabody demonstrated an average tumor-to-blood ratio of 3.0 and positive-to-negative tumor ratio of 7.4. Successful conjugation of the cys-diabody to PLNs was indicated by flow cytometry showing specific binding of cys-diabody-PLN conjugate to human pancreatic cancer cells in vitro.ConclusionsOur results show that the anti-CA19-9 cys-diabody targets pancreatic cancer providing specific molecular imaging in tumor xenograft models. Furthermore, the cys-diabody-PLN conjugate demonstrates target-specific binding of human pancreatic cancer cells with the potential to deliver targeted treatment.
- Published
- 2013