A cleavable molecular adapter reduces side effects and concomitantly enhances efficacy in tumor treatment by targeted...

Area of Science:

• Biotechnology
• Oncology
• Molecular Biology

Background:

• Receptor-targeted toxins for cancer therapy face challenges with systemic toxicity and poor intracellular toxin delivery.
• Current methods struggle to efficiently transfer toxins into the cytosol after cell surface binding.

Purpose of the Study:

• To develop and evaluate a molecular adapter designed to improve the efficacy and safety of chimeric toxins.
• The adapter aims to enhance cytosolic uptake, ensure intracellular toxin retention, and facilitate drug detoxification post-cell death.

Main Methods:

• A molecular adapter was engineered to link a toxic moiety (saporin) and a targeting ligand (epidermal growth factor - EGF).
• The efficacy of the adapter-containing toxin (SA2E) versus an adapter-free construct (SE) was assessed in vivo using tumor models in BALB/c mice.

Main Results:

• The adapter-containing toxin (SA2E) demonstrated a threefold higher lethal dose compared to the adapter-free construct (SE).
• SA2E achieved a 71% reduction in average tumor weight, compared to 33% for SE, with 60% complete tumor suppression.
• SA2E treatment significantly reduced severe side effects, including hyperalgesia and alopecia, and mortality.

Conclusions:

• The molecular adapter significantly enhances the therapeutic index of targeted toxins by improving tumor cell uptake and reducing systemic toxicity.
• SA2E represents a promising advancement in targeted cancer therapy, offering improved efficacy and a better safety profile.
• The observed effects were specific to tumors expressing the target receptor, indicating targeted action and reduced off-target toxicity.