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Multivalent nanobodies targeting death receptor 5 elicit superior tumor cell killing through efficient caspase
Heather A Huet1, Joseph D Growney, Jennifer A Johnson
1a Oncology Research; Novartis Institutes for Biomedical Research ; Cambridge , MA USA.
Abstract:
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.
Insights
Multivalent Nanobodies targeting death receptor 5 (DR5) show enhanced potency against cancer. This novel approach overcomes limitations of current DR5 agonists, demonstrating significant anti-tumor activity and potential for new cancer therapies.
Area of Science:
- Oncology
- Immunology
- Biotechnology
Background:
- Therapeutic agonists targeting death receptor 5 (DR5) have shown limited clinical efficacy despite preclinical promise.
- Existing DR5 agonists, like dimeric antibodies, may require immune cell-mediated cross-linking for optimal DR5 clustering and anti-tumor activity.
- Insufficient potency of current DR5 agonists may explain disappointing clinical outcomes in cancer patients.
Purpose of the Study:
- To develop a more potent DR5 agonist using a novel multivalent Nanobody approach.
- To evaluate the anti-tumor efficacy of multivalent DR5 Nanobodies compared to conventional DR5 agonists.
- To investigate the therapeutic potential of multivalent DR5 Nanobodies in patient-derived tumor models.
Main Methods:
- Design and synthesis of trivalent, tetrameric, and pentameric DR5-targeting Nanobodies.
- In vitro assessment of Nanobody-mediated tumor cell killing and death-inducing signaling complex assembly.
- In vivo evaluation of multivalent Nanobody anti-tumor activity in preclinical cancer models, including patient-derived tumors.
Main Results:
- Increasing Nanobody valency from trivalent to pentameric significantly enhanced tumor cell killing potency in vitro.
- Pentameric DR5 Nanobodies demonstrated superior potency compared to tetrameric versions.
- Multivalent Nanobodies induced faster kinetics of death-inducing signaling complex assembly and caspase activation.
- In vivo studies showed superior anti-tumor activity of multivalent Nanobodies over conventional DR5 agonists, including tumor regression in resistant models.
- Complete responses were observed in up to 50% of patient-derived pancreatic and colon tumor models treated with Nanobodies.
Conclusions:
- Multivalent Nanobodies targeting DR5 represent a novel and highly potent therapeutic strategy.
- This approach overcomes the limitations of current DR5 agonists, offering improved anti-tumor efficacy.
- Multivalent DR5 Nanobodies show significant promise as a new therapeutic modality for various cancers, including treatment-resistant tumors.
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