环状核酸适配体-药物偶联物联合CAR19-T/NK细胞增强对急性淋巴细胞白血病细胞的杀伤作用OA

Objective:To investigate the enhanced cytotoxic effect of circular nucleic acid aptamer-drug conjugates(ApDC)combined with anti-CD19 chimeric antigen receptor T/NK(CAR19-T/NK)cells on Nalm6 leukemia cells.Methods:Database analysis was used to identify the marker protein tyrosine kinase 7(PTK7)in leukemia cells.An aptamer targeting PTK7,sgc8,was designed and synthesized.Subsequently,two ApDCs were prepared:nucleic acid aptamer-conjugated gemcitabine(sgc8-GEM)and circular nucleic acid aptamer-conjugated gemcitabine(C-sgc8-GEM).Their stability was analyzed using agarose gel electrophoresis.Human peripheral blood T/NK cells were transfected with CD19-CAR overexpression lentivirus to construct CAR19-T and CAR19-NK cells.The binding affinity of sgc8 to Nalm6 cells was detected using flow cytometry.The cytotoxicity of sgc8-GEM,C-sgc8-GEM,and their combination with CAR19-T or CAR19-NK cells against Nalm6 cells was evaluated using CCK-8 assay and flow cytometry.Results:PTK7 mRNA was highly expressed in leukemia cells(P<0.01).C-sgc8-GEM exhibited higher stability than sgc8-GEM,and sgc8-GEM exhibited more effective cytotoxicity against Nalm6 cells compared to GEM alone(P<0.001).The combination of C-sgc8-GEM or sgc8-GEM with CAR19-T/NK cells showed significantly stronger cytotoxicity against Nalm6 cells than C-sgc8-GEM,sgc8-GEM,or CAR19-T/NK cells alone(P<0.001).Conclusion:The circular ApDCs combined with CAR19-T/NK cells were successfully developed.This dual-targeting strategy effectively increased the cytotoxicity against Nalm6 cells,providing a new treatment approach for acute lymphoblastic leukemia.