Dasatinib is a potent enhancer for CAR T cell generation by CD3-targeted lentiviral vectors

Abstract

CD3-targeted lentiviral vectors (CD3-LVs) mediate selective transduction of human T lymphocytes invitro and invivo while simultaneously activating the targeted cells. Previously, we have demonstrated that CD3-LV leads to downmodulation of the CD3:T cell receptor (TCR) complex. We therefore hypothesized that inhibition of CD3 phosphorylation by Src/Abl tyrosine kinase inhibitors such as dasatinib results in enhancement of gene delivery by Tcell-targeted LVs. Indeed, dasatinib treatment of Tcells prior to incubation with CD3-LV increased reporter gene delivery by 3- to 10-fold. Moreover, the presence of dasatinib enhanced selective transduction into non-activated target cells present in whole blood. When combined with delivery of the CD19-chimeric antigen receptor (CAR) gene, dasatinib increased CAR Tcell numbers by close to 10-fold. Importantly, the short-term exposure of Tcells to dasatinib during vector incubation did not interfere with tumor cell killing by the resulting CAR Tcells and rather came along with less upregulated exhaustion markers and a more naive phenotype. Our data suggest that dasatinib prevents CD3-LV-induced phosphorylation and CD3:TCR intake, thereby increasing the amount of CD3-LV bound to the cell surface. This is the first description of dasatinib as transduction enhancer, an activity particularly relevant for CAR Tcell generation with CD3-LV.