Dasatinib enhances anti-tumor efficacy of chimeric antigen receptor T cells by inhibiting cell differentiation and exhaustion
CD19-targeted Chimeric antigen receptor T cells (CART) cells have shown remarkable promise in various B cell malignancies. Sustained tonic signaling and antigen exposure drives CART cell differentiation and exhaustion, which limits the therapeutic potency and persistence of CART cells and is a major cause of CD19-expressing leukemia relapse after CD19-targeted CART cells treatment in ALL. Here, we systematically screened FDA approved tyrosine kinase inhibitors, and identified dasatinib as the best candidate to prevent or reverse both CD28/CART and 4-1BB/CART cells from differentiation and exhaustion during ex vivo expansion, which enhanced the therapeutic efficacy and in vivo persistence. Using RNA-seq, we identified the differentially expressed genes between dasatinib treated group and Nalm6 stimulated group, and found that memory-associated transcription factors TCF7 and naive/memory-associated cell surface marker CCR7 were upregulated, whereas exhaustion-related regulators (NR4A1, BATF3, ATF4 and FOS) and inhibitory receptors (PD1, LAG3) were down-regulated in dasatinib treated CAR T cells. Moreover, T cell activation associated signaling pathways (T cell receptor, Jak-STAT, MAPK and PI3K-Akt) which were upregulated in Nalm6 stimulated CART cells, showed fundamental downregulation in dasatinib treated CART cells. These findings imply that dasatinib played important roles in CART cell differentiation and exhaustion by inhibition of T cell activation pathways. Overall design: For experiments of the impacts of dasatinib on differentiation and exhaustion of CART cells stimulated by Nalm6, GFP+ 4-1BB CART cells were sorted at 3-5 days after transfection and expanded for another 3-7 days, then treated with Nalm6 for 48 hours, and then dasatinib or imatinib was added for another 48 hours. The CART cells of each group were harvested and performed RNA-seq.