An Anti-Transferrin Receptor-Avidin Fusion Protein Exhibits Both Strong Proapoptotic Activity and the Ability to Deliver Various Molecules into Cancer Cells

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 99; no. 16; pp. 10706 - 10711
• Main Authors: Ng, Patrick P., Dela Cruz, Jay S., Sorour, David N., Stinebaugh, James M., Shin, Seung-Uon, Shin, Daniel S., Morrison, Sherie L., Penichet, Manuel L.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 06.08.2002; National Acad Sciences
• Subjects: Animals; Antibodies - administration & dosage; Antibodies - genetics; Antibodies - metabolism; Antibodies - pharmacology; Antineoplastic Agents - administration & dosage; Antineoplastic Agents - metabolism; Antineoplastic Agents - pharmacology; Apoptosis; Avidin - genetics; Avidin - metabolism; Avidin - pharmacology; Biological Sciences; Biotin; Blood cells; Cancer; Cell Division; Cell growth; Cell lines; Cross-Linking Reagents; Cytometry; Delta cells; Dimerization; Drug Delivery Systems; Drug therapy; Endocytosis; Fluorescein-5-isothiocyanate - administration & dosage; Glucose Oxidase - metabolism; Humans; Ice; Immunoconjugates - administration & dosage; Immunoconjugates - pharmacology; Immunoglobulin G - genetics; Immunoglobulin G - metabolism; K562 Cells; Medical research; Molecules; Proteins; Rats; Receptors, Transferrin - administration & dosage; Receptors, Transferrin - immunology; Receptors, Transferrin - metabolism; Recombinant Fusion Proteins - administration & dosage; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; T lymphocytes; Tumor Cells, Cultured
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.162362999

We have developed an antibody fusion protein (anti-rat TfR IgG3-Av) with the ability to deliver different molecules into cancer cells. It consists of avidin genetically fused to the CH3region of a human IgG3 specific for the rat transferrin receptor. It forms strong, noncovalent interactions with biotinylated molecules such as glucose oxidase and β-galactosidase, and delivers them into the rat myeloma cell line Y3-Ag1.2.3 through receptor-mediated endocytosis. Importantly, the β-galactosidase retains activity after internalization. Furthermore, we have unexpectedly discovered that anti-rat TfR IgG3-Av, but not a recombinant anti-rat TfR IgG3 or a nonspecific IgG3-Av, possesses proapoptotic activities against Y3-Ag1.2.3 and the rat T cell lymphoma cell line C58 (NT) D.1.G.OVAR. 1. These activities were not observed in two rat cell lines of nonhematopoietic lineage (bladder carcinoma BC47 and gliosarcoma 9L).Anti-humanTfR IgG3-Avalso demonstrated proapoptotic activity against the human erythroleukemia cell line K562. Studies showed that anti-rat TfR IgG3-Av exists as a dimer, suggesting that cross-linking of the surface transferrin receptor may be responsible for the cytotoxic activity. These findings demonstrate that it is possible to transform an antibody specific for a growth factor receptor that does not exhibit inhibitory activity into a drug with significant intrinsic cytotoxic activity against selected cells by fusing it with avidin. The antitumor activity may be enhanced by delivering biotinylated therapeutics into cancer cells. Further development of this technology may lead to effective therapeutics for in vivo eradication of hematological malignancies, and ex vivo purging of cancer cells in autologous transplantation.