Author ORCID Identifier

https://orcid.org/0009-0006-6639-3662

Document Type

Thesis

Date of Award

Spring 4-25-2025

Keywords

ADC, cancer, Exatecan, TLR7 agonist, thermal stability, plasma stability, aggregation, biological stability

Degree Name

Biochemistry (BS)

Department

BIOCHEMISTRY

First Advisor

Dr. L. Nathan Tumey

Series

Science and Mathematics

Abstract

Antibody-drug conjugates (ADCs) offer targeted drug delivery of potent cytotoxic payloads, minimizing systemic toxicity. However, the stability of the linker is integral to ensure that there is minimal off-target payload release and little systemic toxicity. This study analyzes the physical and biological stability of our new legumain-cleavable vs traditional cathepsin-cleavable antibody-drug conjugates (ADCs), with a focus on hydrophobicity, thermal stability, aggregation, and biological payload release. Our findings indicate that decreased hydrophobicity of the legumain-cleavable ADCs compared to cathepsin-cleavable ADCs is correlated with decreased aggregation (predicting lower uptake by liver macrophages and therefore slower clearance and less systemic toxicity) and lower amounts of off-target payload release (predicting less systemic toxicity). Exatecan ADCs employing the mcGlyAsnAsn(GABA)_Exatecan linker-payload had the greatest amount of stability across the experiments. However, our studies suggest that both legumain-cleavable and cathepsin-cleavable ADCs are susceptible to cleavage by proteases secreted by macrophages present in the tumor microenvironment; legumain-cleavable ADCs offer no improvements in this regard. Overall, this study provides valuable insights into the development of ADCs with enhanced stability and reduced off-target toxicity.

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