Pronounced antitumor efficacy by extracellular activation of a doxorubicin-glucuronide prodrug after adenoviral vector-mediated expression of a human antibody-enzyme fusion protein.

Abstract

Tumor-specific activation of the glucuronide prodrug of doxorubicin, N-[4-doxorubicin-N-carbonyl(oxymethyl)phenyl]-O-beta-glucuronyl carbamate (DOX-GA3), by beta-glucuronidase present in necrotic tumor areas might be improved after transduction of tumor cells to secrete a targeted form of beta-glucuronidase. To that end, we constructed an adenovirus vector, designated Ad/C28-GUSh, encoding human beta-glucuronidase fused to a human single-chain Fv (scFv) against the epithelial cell adhesion molecule (EpCAM), C28, and preceded by a signal sequence for secretion. Antibody specificity and enzyme activity were retained in the fusion protein secreted by tumor cells infected with Ad/C28-GUSh. Diffusion of fusion protein from transduced tumor cells within MCF-7 multicellular spheroids was visualized by immunohistochemistry. Treatment of spheroids with Ad/C28-GUSh and DOX-GA3 resulted in growth inhibition comparable to treatment with doxorubicin alone. Treatment of well-established FMa human ovarian cancer xenografts with intravenous injection of DOX-GA3 (500 mg/kg) resulted in a tumor volume-doubling time of 23.8 days compared to 8.0 days for phosphate-buffered saline (PBS)-treated mice. Intratumoral administration of Ad/C28-GUSh before DOX-GA3 enhanced the growth inhibition and increased the tumor volume-doubling time to 43.1 days (p < 0.01), while virus alone had no effect. Thus, we have successfully shown that an adenovirus vector encoding a secreted, targeted form of human beta-glucuronidase can further improve DOX-GA3 monotherapy.

• Authors: Michelle de Graaf, Herbert M Pinedo, Dinja Oosterhoff, Ida H van der Meulen-Muileman, Winald R Gerritsen, Hidde J Haisma, Epie Boven
• Journal: Human gene therapy (Hum Gene Ther) Vol. 15 Issue 3 Pg. 229-38 (Mar 2004) ISSN: 1043-0342 [Print] United States
• PMID: 15018732 (Publication Type: Journal Article)

Chemical References

• Ad-C28-GUSh
• Antibodies
• Antigens, Neoplasm
• Antineoplastic Agents
• Cell Adhesion Molecules
• Epithelial Cell Adhesion Molecule
• Glucuronates
• N-(4-doxorubicin-N-carbonyl(oxymethyl)phenyl)-O-glucuronyl carbamate
• Prodrugs
• Recombinant Fusion Proteins
• Doxorubicin
• Glucuronidase

Topics

• Adenoviridae (genetics)
• Animals
• Antibodies (immunology)
• Antigens, Neoplasm (immunology)
• Antineoplastic Agents (therapeutic use)
• Cell Adhesion Molecules (immunology)
• Cell Line, Tumor
• Doxorubicin (analogs & derivatives, therapeutic use)
• Epithelial Cell Adhesion Molecule
• Female
• Flow Cytometry
• Gene Transfer Techniques
• Genetic Vectors
• Glucuronates (therapeutic use)
• Glucuronidase (metabolism)
• Humans
• Mice
• Neoplasms (drug therapy)
• Ovarian Neoplasms (drug therapy)
• Prodrugs (therapeutic use)
• Protein Binding
• Recombinant Fusion Proteins (genetics, metabolism)
• Spheroids, Cellular
• Xenograft Model Antitumor Assays