Targeting CD20+ Aggressive B-cell Non-Hodgkin Lymphoma by Anti-CD20 CAR mRNA-Modified Expanded Natural Killer Cells In Vitro and in NSG Mice

The prognosis is very dismal for patients with relapsed CD20(+) B-cell non-Hodgkin lymphoma (B-NHL). Facilitating the development of alternative novel therapeutic strategies is required to improve outcomes in patients with recurrent/refractory CD20(+) B-NHL. In this study, we investigated functional activities of anti-CD20 CAR-modified, expanded peripheral blood NK cells (exPBNK) following mRNA nucleofection against CD20(+) B-NHL in vitro and in vivo. CAR(+) exPBNK had significantly enhanced in vitro cytotoxicity, compared with CAR(-) exPBNK against CD20(+) Ramos (P < 0.05), Daudi, Raji, and two rituximab-resistant cell lines, Raji-2R and Raji-4RH (P < 0.001). As expected, there was no significant difference against CD20(-) RS4; 11 and Jurkat cells. CD107a degranulation and intracellular IFN gamma production were also enhanced in CAR(+) exPBNK in response to CD20(+) B-NHL-specific stimulation. In Raji-Luc and Raji-2R-Luc xenografted NOD/SCID/gamma-chain(-/-) (NSG) mice, the luciferase signals measured in the CAR(+) exPBNK-treated group were significantly reduced, compared with the signals measured in the untreated mice and in mice treated with the CAR(-) exPBNK. Furthermore, the CAR exPBNK-treated mice had significantly extended survival time (P < 0.001) and reduced tumor size, compared with those of the untreated and the CAR(-) exPBNK-treated mice (P < 0.05). These preclinical data suggest that ex vivo-exPBNK modified with anti-CD20 CAR may have therapeutic potential for treating patients with poor-risk CD20(+) hematologic malignancies.