Preclinical development and selection of nanobody-based CAR-T cells targeting HER2-positive solid tumors

Area of Science:

• Immunotherapy
• Oncology
• Biotechnology

Background:

• Chimeric antigen receptor (CAR)-T cell therapy shows success in blood cancers but faces challenges in solid tumors.
• Nanobodies offer advantages for CAR design, yet their impact on CAR-T cell function requires further investigation.

Purpose of the Study:

• To evaluate and compare the efficacy of 12 distinct nanobody-based CAR-T cell constructs targeting HER2 in solid tumors.
• To identify optimal nanobody CAR designs for enhanced anti-tumor activity and to select a lead candidate for further development.

Main Methods:

• Side-by-side screening of 12 nanobody-based CARs (nanoCARs) against HER2-expressing cells.
• In vitro assessment of T cell activation, cytokine secretion, and cytotoxicity against glioblastoma, breast cancer, and melanoma cell lines.
• In vivo evaluation of a lead nanoCAR in a xenograft tumor model.

Main Results:

• All nanoCARs recognized HER2-positive cells, with 6/12 showing significant reactivity and cytotoxicity against HER2-positive glioblastoma and breast cancer cells.
• Only one nanoCAR demonstrated potent cytotoxicity against HER2-positive melanoma cells.
• A lead nanoCAR (1R59b) exhibited superior cytotoxicity across multiple solid tumor cell lines and demonstrated tumor control in vivo.

Conclusions:

• Nanobody selection for CAR-T cell therapy necessitates extensive screening, as efficacy varies significantly.
• The identified lead nanoCAR (1R59b) shows promise as a potential therapeutic agent for HER2-positive solid tumors, warranting further preclinical investigation.