Next-generation cell-penetrating antibodies for tumor targeting and RAD51 inhibition

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• Monoclonal antibody therapies are successful but mainly target cell surface antigens.
• Many cancer targets are intracellular, limiting current antibody therapy applications.
• The lupus-derived autoantibody 3E10 shows potential for intracellular targeting.

Purpose of the Study:

• To humanize the 3E10 antibody for potential cancer therapy.
• To investigate the mechanism of cell penetration and tumor targeting of 3E10 variants.
• To evaluate the therapeutic potential of humanized 3E10 against intracellular targets.

Main Methods:

• Humanization of the monoclonal antibody 3E10.
• Assessment of cell uptake via nucleoside transporter ENT2.
• Evaluation of antibody affinity for nucleic acids and RAD51 binding.
• In vivo tumor targeting studies in preclinical models.

Main Results:

• Humanized 3E10 variants demonstrated cell uptake dependent on ENT2.
• Higher nucleic acid binding affinity correlated with faster cell uptake and enhanced tumor targeting.
• One human variant retained binding to RAD51, inhibiting homology-directed repair.
• The antibody showed specific tumor targeting after systemic administration.

Conclusions:

• Humanized 3E10 antibody is a promising platform for targeting intracellular cancer proteins.
• ENT2-mediated cell penetration is crucial for antibody efficacy.
• Targeting RAD51 offers a synthetic lethal approach for cancer treatment.
• This antibody platform enables rational design for specific systemic cancer therapy.