St3gal1 and bII-spectrin pathways control CAR-T cell migration to target tumor sites [1]

Adoptive transfer of genetically engineered chimeric antigen receptor (CAR)-T cell is emerging as a promising treatment option for hematological malignancies. However, T cell immunotherapies have largely failed in patients with solid tumors. Here, with a CRISPR-Cas9 pooled library, we performed an in vivo targeted loss-of-function screen and identified ST3 b-galactoside a-2,3-sialyltransferase 1 (St3gal1) as a key negative regulator of the cancer-specific migration of CAR-T cells. Analysis of glycosylated proteins reveals that CD18 is a major effector of St3gal1 in activated CD8 T cells. St3gal1-mediated glycosylation induces the spontaneous nonspecific tissue sequestration of T cells by altering lymphocyte function-associated antigen-1 (LFA-1) endocytic recycling. Engineered CAR-T cells with enhanced expression of bII-spectrin, a key LFA-1 associated cytoskeleton molecule, reversed St3gal1-mediated nonspecific T cell migration and significantly reduced tumor growth in mice by improving tumor-specific homing of CAR-T cells. These findings identify a role of the St3gal1- bII-spectrin axis as the key cell-intrinsic program for cancer targeting CAR-T cell migration and as a promising strategy for effective T cell immunotherapy. WT mice bearing B16-OVA tumors received freshly prepared hHER2 CAR-T cells and CAR-T cells isolated from the each organ 24 hr after adoptive transfer (n=3).