Extracellular Antibody Drug Conjugates Exploiting the Proximity of Two Proteins

Area of Science:

• Biochemistry
• Cell Biology
• Oncology

Background:

• The Na+/K+-ATPase (NKA) is crucial for maintaining cellular resting potential.
• NKA inhibition causes cell swelling and death, indicating its vital role.
• Cancer cells exhibit NKA in proximity to cancer-related proteins.

Purpose of the Study:

• To investigate targeting the NKA on cancer cells with a novel precision therapy.
• To develop and characterize extracellular drug conjugates (EDCs) for cancer treatment.
• To establish a framework for a new class of targeted cancer therapies.

Main Methods:

• Covalent attachment of a small molecule NKA inhibitor to antibodies targeting cancer cell surface proteins (CD20, CD38, CD56, CD147, dysadherin).
• Creation and testing of selective extracellular drug conjugates (EDCs).
• Evaluation of EDC efficacy, including EC50 values and signal-to-noise ratios.

Main Results:

• EDCs demonstrated low to mid-picomolar EC50 values and high signal-to-noise ratios (>1,000:1).
• EDC efficacy was dependent on NKA and target protein expression on cancer cells.
• Developed potent and selective EDCs that induce extracellular cancer cell death via necrosis-like mechanisms.

Conclusions:

• The NKA can be effectively targeted on cancer cells using antibody-drug conjugates.
• EDCs represent a promising new strategy for precision cancer therapy.
• This framework enables the development of highly selective therapies targeting extracellular disease-related proteins.