Multivalent nanobodies targeting death receptor 5 elicit superior tumor cell killing through efficient caspase induction

• Published in: mAbs 2014, Vol.6 (6), p.1560-1570
• Main Authors: Huet, Heather A, Growney, Joseph D, Johnson, Jennifer A, Li, Jing, Bilic, Sanela, Ostrom, Lance, Zafari, Mohammad, Kowal, Colleen, Yang, Guizhi, Royo, Axelle, Jensen, Michael, Dombrecht, Bruno, Meerschaert, Kris R A, Kolkman, Joost A, Cromie, Karen D, Mosher, Rebecca, Gao, Hui, Schuller, Alwin, Isaacs, Randi, Sellers, William R, Ettenberg, Seth A
• Format: Article
• Language: English
• Subjects: Animals; Antibody Affinity - immunology; Blotting, Western; Caspases - biosynthesis; Caspases - immunology; Cell Line, Tumor; Cell Survival - drug effects; Cell Survival - immunology; Cells, Cultured; Dose-Response Relationship, Drug; Enzyme Induction - drug effects; HCT116 Cells; Humans; Interleukin Receptor Common gamma Subunit - deficiency; Interleukin Receptor Common gamma Subunit - genetics; Mice, Inbred NOD; Mice, Knockout; Mice, Nude; Mice, SCID; Neoplasms - drug therapy; Neoplasms - immunology; Protein Multimerization; Receptors, TNF-Related Apoptosis-Inducing Ligand - agonists; Receptors, TNF-Related Apoptosis-Inducing Ligand - immunology; Single-Domain Antibodies - chemistry; Single-Domain Antibodies - immunology; Single-Domain Antibodies - pharmacology; Surface Plasmon Resonance; Xenograft Model Antitumor Assays
• ISSN: 1942-0862; 1942-0870
• DOI: 10.4161/19420862.2014.975099

Multiple therapeutic agonists of death receptor 5 (DR5) have been developed and are under clinical evaluation. Although these agonists demonstrate significant anti-tumor activity in preclinical models, the clinical efficacy in human cancer patients has been notably disappointing. One possible explanation might be that the current classes of therapeutic molecules are not sufficiently potent to elicit significant response in patients, particularly for dimeric antibody agonists that require secondary cross-linking via Fcγ receptors expressed on immune cells to achieve optimal clustering of DR5. To overcome this limitation, a novel multivalent Nanobody approach was taken with the goal of generating a significantly more potent DR5 agonist. In the present study, we show that trivalent DR5 targeting Nanobodies mimic the activity of natural ligand, and furthermore, increasing the valency of domains to tetramer and pentamer markedly increased potency of cell killing on tumor cells, with pentamers being more potent than tetramers in vitro. Increased potency was attributed to faster kinetics of death-inducing signaling complex assembly and caspase-8 and caspase-3 activation. In vivo, multivalent Nanobody molecules elicited superior anti-tumor activity compared to a conventional DR5 agonist antibody, including the ability to induce tumor regression in an insensitive patient-derived primary pancreatic tumor model. Furthermore, complete responses to Nanobody treatment were obtained in up to 50% of patient-derived primary pancreatic and colon tumor models, suggesting that multivalent DR5 Nanobodies may represent a significant new therapeutic modality for targeting death receptor signaling.