CELL INTELLIGENCE · 肿瘤细胞治疗研究

BACKGROUND: Chimeric antigen receptor (CAR) T-cell therapy target receptor tyrosine kinase-like orphan receptor 1 (ROR1) is broadly expressed in hematologic and solid tumors, however clinically-characterized ROR1-CAR T cells with single chain variable fragment (scFv)-R12 targeting domain failed to induce durable remissions, in part due to the immunosuppressive tumor microenvironment (TME). Herein, we describe the development of an improved ROR1-CAR with a novel, fully human scFv9 targeting domain, and augmented with TGF RIIDN armor protective against a major TME factor, transforming growth factor beta (TGF ). METHODS: CAR T cells were generated by lentiviral transduction of enriched CD4 + and CD8 + T cells, and the novel scFv9-based ROR1-CAR-1 was compared with the clinically-characterized ROR1-R12-scFv-based CAR-2 in vitro and in vivo. RESULTS: CAR-1 T cells exhibited greater CAR surface density than CAR-2 when normalized for %CAR + , and produced more interferon (IFN)- tumor necrosis factor (TNF)- and interleukin (IL)-2 in response to hematologic (Jeko-1, RPMI-8226) and solid (OVCAR-3, Capan-2, NCI-H226) tumor cell lines in vitro. In vivo, CAR-1 and CAR-2 both cleared hematologic Jeko-1 lymphoma xenografts, however only CAR-1 fully rejected ovarian solid OVCAR-3 tumors, concordantly with greater expansion of CD8 + and CD4 + CAR T cells, and enrichment for central and effector memory phenotype. When equipped with TGF -protective armor TGF RIIDN, CAR-1 T cells resisted TGF -mediated pSmad2/3 phosphorylation, as compared with CAR-1 alone. When co-cultured with ROR-1 + AsPC-1 pancreatic cancer line in the presence of TGF 1, armored CAR-1 demonstrated improved recovery of killing function, IFN- , TNF- and IL-2 secretion. In mouse AsPC-1 pancreatic tumor xenografts overexpressing TGF 1, armored CAR-1, in contrast to CAR-1 alone, achieved complete tumor remissions, and yielded accelerated expansion of CAR + T cells, diminished circulating active TGF 1, and no apparent toxicity or weight loss. Unexpectedly, in AsPC-1 xenografts without TGF overexpression, TGF 1 production was specifically induced by ROR-1-CAR T cells interaction with ROR-1 positive tumor cells, and the TGF RIIDN armor conferred accelerated tumor clearance. CONCLUSIONS: The novel fully human TGF RIIDN-armored ROR1-CAR-1 T cells are highly potent against ROR1-positive tumors, and withstand the inhibitory effects of TGF in solid TME. Moreover, TGF 1 induction represents a novel, CAR-induced checkpoint in the solid TME, which can be circumvented by co-expressing the TG RIIDN armor on T cells.