Photoimmunotherapy of HER2-expressing Breast Cancer Cells

Area of Science:

• Oncology
• Immunotherapy
• Bioconjugation

Background:

• Breast cancer (BC) recurrence after surgery necessitates systemic treatments.
• Local recurrence impacts quality of life and survival.
• Intraoperative therapies are needed to eliminate residual tumor cells.

Purpose of the Study:

• Develop a novel antibody-dye conjugate for breast cancer photoimmunotherapy (PIT).
• Investigate the efficacy of this conjugate in eliminating residual tumor cells intraoperatively.

Main Methods:

• Engineered a cysteine-modified trastuzumab variant.
• Coupled trastuzumab to the silicon phthalocyanine dye WB692-CB1.
• Assessed conjugate binding via flow cytometry and cell killing post-irradiation.

Main Results:

• The antibody-dye conjugate specifically binds to HER2-expressing BC cells.
• Irradiation of HER2-high SK-BR-3 cells with the conjugate resulted in complete cell death within 24 hours.

Conclusions:

• The novel antibody-dye conjugate shows promise for intraoperative BC treatment.
• This approach may reduce local recurrence and improve patient recovery.
• Photoimmunotherapy offers a new strategy for localized breast cancer management.