CAR-T Entering a New "Phase": Improving CAR-T Function by Harnessing Phase Separation.

Area of Science:

• Biochemistry
• Immunology
• Cell Biology

Background:

• Biomolecular condensation via liquid-liquid phase separation is crucial for biological organization.
• The T-cell receptor complex, including the CD3ε subunit, plays a key role in immune responses.

Purpose of the Study:

• To investigate if the CD3ε subunit's cytoplasmic tail can induce biomolecular condensation in chimeric antigen receptors (CARs).
• To engineer modified CD3ε sequences to enhance CAR T-cell function and therapeutic efficacy.

Main Methods:

• Fusion of the CD3ε cytoplasmic tail to a CAR.
• Sequence engineering of the CD3ε moiety.
• Assessment of CAR condensation, immunologic synapse maturation, and coreceptor signaling.
• Evaluation of in vitro cytotoxicity and in vivo antitumor effects in mouse xenograft models.

Main Results:

• The CD3ε cytoplasmic tail promoted CAR condensation through liquid-liquid phase separation.
• Sequence modifications of CD3ε enhanced immunologic synapse maturation and coreceptor signaling.
• Engineered CAR T-cells exhibited improved in vitro cytotoxicity and significant antitumor effects in vivo.

Conclusions:

• Biomolecular condensation can be leveraged to enhance CAR T-cell functionality.
• Engineered CD3ε sequences represent a promising strategy for next-generation cell therapies.
• This approach offers a novel avenue for improving cancer immunotherapy.