Anticancer activity and antibody-dependent cell-mediated cytotoxicity of novel anti-nucleolin antibodies

Area of Science:

• Immunology
• Oncology
• Biotechnology

Background:

• Nucleolin is overexpressed on cancer and angiogenic endothelial cells, making it a promising dual-targeting strategy for cancer therapy.
• Immunotherapeutic strategies against nucleolin are underexplored despite their therapeutic potential.

Purpose of the Study:

• To engineer novel anti-nucleolin VHH-based antibodies capable of eliciting anticancer immune responses.
• To develop an antibody format that can trigger antibody-dependent cell-mediated cytotoxicity (ADCC).

Main Methods:

• Generation of anti-nucleolin VHHs by grafting nucleolin-binding sequences onto VHH CDR1 or CDR3.
• Fusion of a nucleolin-binding CDR3-grafted VHH to a human IgG1 Fc region to create a VHH-Fc fusion protein.
• Assessment of binding affinity, antiproliferative effects, and ADCC activity against cancer cells.

Main Results:

• Engineered anti-nucleolin VHHs showed enhanced binding and antiproliferative effects compared to parental VHH.
• The VHH-Fc fusion protein exhibited increased cytotoxicity and triggered significant ADCC in the nanomolar range.
• ADCC activity resulted in a 2-fold or 1.7-fold increase in cancer cell death in the presence of PBMCs.

Conclusions:

• The developed anti-nucleolin VHHs are the first of their kind.
• The VHH-Fc fusion protein is the first anti-nucleolin antibody demonstrating ADCC activity.
• These findings pave the way for novel immunotherapeutic strategies targeting nucleolin in cancer treatment.