Breast cancer targeted/ therapeutic with double and triple fusion Immunotoxins

Area of Science:

• Oncology
• Biotechnology
• Molecular Biology

Background:

• Targeted delivery of therapeutics can improve cancer treatment efficacy and minimize damage to healthy tissues.
• Human Epidermal growth factor Receptor 2 (HER2) is a tumor marker present in 25-30% of breast cancer patients, making it a significant target for therapy.
• HER2 monoclonal antibody (mAb) therapy is an established approach for treating HER2-positive breast cancer.

Purpose of the Study:

• To develop and evaluate a novel recombinant immunotoxin (IT) by fusing a HER2-targeting antibody (Herceptin) with a cytotoxic payload (PE38).
• To assess the binding ability, cytotoxicity, cellular uptake, and apoptosis-inducing potential of the developed ITs against HER2-positive and HER2-negative breast cancer cells.

Main Methods:

• Recombinant DNA technology was used to create fusion proteins: scFv(Herceptin)-PE-STXA and scFv(Herceptin)-PE.
• Proteins were expressed and purified using pET28a vector.
• Cytotoxicity was evaluated using MTT assay on HER2-negative (MCF-7) and HER2-positive (SKBR-3) breast cancer cell lines.
• Cell ELISA, internalization studies, and apoptosis assays were performed to assess IT activity.

Main Results:

• The recombinant ITs exhibited specific binding to HER2-positive SKBR-3 cells but not to HER2-negative MCF-7 cells.
• Significant dose-dependent cytotoxicity was observed in SKBR-3 cells, while MCF-7 cells remained largely unaffected.
• Evidence suggested that the ITs are internalized by cancer cells and induce apoptosis.

Conclusions:

• The developed recombinant immunotoxins possess therapeutic potential for targeting and eradicating HER2-positive breast cancer cells.
• This targeted approach offers a promising strategy for enhancing cancer therapy efficacy while potentially reducing systemic toxicity.
• Further investigation is warranted to explore the clinical applicability of these novel HER2-targeted immunotoxins.