VHH-Based CAR-T Cells Targeting DLL3 Show High Efficacy in Small Cell Lung Cancer Models

Area of Science:

• Immunology
• Oncology
• Biotechnology

Background:

• Small cell lung cancer (SCLC) is aggressive with poor prognosis and limited treatments.
• Delta-like ligand 3 (DLL3) is a promising therapeutic target for SCLC.
• Variable domain of heavy-chain-only antibodies (VHH) CAR T cells show enhanced efficacy over ScFv counterparts.

Purpose of the Study:

• To explore the therapeutic potential of anti-DLL3 VHH-CAR T cells for SCLC.
• To develop and evaluate humanized VHH-CAR T cells targeting DLL3.
• To assess the in vitro and in vivo efficacy of these engineered T cells.

Main Methods:

• Alpaca immunization and yeast display screening for anti-DLL3 VHHs.
• Affinity, specificity, and cytotoxicity assessment of VHH clones in CAR T cell models.
• Humanization of lead VHH sequence (1-B12) and evaluation of resulting HM-CAR T cells in vitro and in vivo.

Main Results:

• Identified and characterized potent anti-DLL3 VHHs with high affinity, specificity, and cytotoxicity.
• Selected humanized VHH (1-B12) demonstrated superior characteristics.
• HM-CAR T cells exhibited robust cytokine production, tumor cell cytotoxicity, and significant in vivo antitumor efficacy.

Conclusions:

• Effective strategies for developing DLL3-specific VHHs were established.
• Anti-DLL3 VHH-CAR T cells show significant potential as an immunotherapeutic approach for DLL3-expressing cancers.
• This approach supports the clinical translation of VHH-CAR T therapy for SCLC and other DLL3+ malignancies.