A novel phosphoester-based cationic co-polymer nanocarrier delivers chimeric antigen receptor plasmid and exhibits anti-tumor effect.

Chimeric antigen receptor T cells (CAR-T cells) targeting of CD19 antigen has been proven to be effective and successful in B cell acute lymphoblastic leukemia. The traditional CAR delivery systems have several problems such as poor biosafety, low loading capacity, and low transfection efficiency. Utilization of nanocarriers for CAR delivery offers new possibilities for CAR-T treatment. In the present study, an anti-CD19 CAR expression lentivirus plasmid was constructed for CAR delivery and immunotherapy. In addition, a three-segment amphiphilic co-polymer, methoxy polyethylene glycol-branched polyethyleneimine-poly(2-ethylbutyl phospholane) (mPEG-bPEI-PEBP) was synthesized via click reaction as the carrier with cationic PEI, capable of delivering the CAR and packaging plasmids to co-transfect Jurkat cells and undergo expression. The PEBP and mPEG parts of the co-polymer provide hydrophobic and hydrophilic interfaces and lead to the co-polymer self-assembly into micelles in water and encapsulation of the DNA plasmids. The mPEG-bPEI-PEBP-DNA composites with different N/P ratios were incubated with the CD19 overexpression K562 cells to identify the CAR functions. The obtained CAR-Jurkat cells had the ability to secrete interferon-γ and interleukin-2. The cytotoxic effects to CD19-K562 cells suggest that the induced CAR-Jurkat cells have an excellent targeted antitumor activity.