Exploring EGFR, Nectin-4, and TROP-2 as Therapeutic Targets for Bladder Cancer Photoimmunotherapy

Area of Science:

• Oncology
• Immunotherapy
• Bioconjugation

Background:

• Non-muscle invasive bladder cancer (NMIBC) presents limited treatment options and high recurrence rates.
• Photoimmunotherapy (PIT) offers targeted tumor ablation via antibody-photosensitizer conjugates activated by light.
• Evaluating epidermal growth factor receptor (EGFR), Nectin-4, and TROP-2 as potential PIT targets.

Purpose of the Study:

• To engineer cysteine-modified antibodies targeting EGFR, Nectin-4, and TROP-2 for photoimmunotherapy.
• To assess the binding affinity and light-induced cytotoxicity of antibody-photosensitizer conjugates in bladder cancer cells.
• To determine the most effective target for PIT in NMIBC.

Main Methods:

• Site-specific conjugation of photosensitizer WB692-CB2 to engineered cysteine residues (T120C, D265C) on antibodies targeting EGFR, Nectin-4, and TROP-2.
• Flow cytometry to confirm antigen binding of the antibody conjugates to bladder cancer cells.
• Cell viability assays to measure light-induced cytotoxicity following irradiation.

Main Results:

• Cysteine-modified antibodies were successfully conjugated with WB692-CB2 while retaining antigen specificity.
• Sacituzumab (anti-TROP-2) conjugate demonstrated superior target binding and near-complete cell killing at 32 J/cm² red light.
• Cetuximab (anti-EGFR) and Enfortumab (anti-Nectin-4) conjugates showed lower potency, with no observed cytotoxicity in antigen-negative cells.
• Combined treatments exhibited enhanced cytotoxicity, suggesting additive phototherapeutic effects.

Conclusions:

• Targeting TROP-2 via PIT with Sacituzumab conjugate shows significant potential for NMIBC treatment.
• EGFR and Nectin-4 are also viable targets for PIT, though less potent in this study.
• Further preclinical development of PIT targeting these antigens is warranted for NMIBC, including combination and personalized strategies.