Suppression of Human Glioma Xenografts with Second-Generation IL13R-Specific Chimeric Antigen Receptor–Modified T Cells

Abstract

Purpose Glioblastoma multiforme (GBM) remains highly incurable, with frequent recurrences after standard therapies of maximal surgical resection, radiation, and chemotherapy. To address the need for new treatments, we have undertaken a chimeric antigen receptor (CAR) “designer T cell” (dTc) immunother-apeutic strategy by exploiting interleukin (IL)13 receptor α-2 (IL13Rα2) as a GBM-selective target. Experimental Design We tested a second-generation IL13 “zetakine” CAR composed of a mutated IL13 extracellular domain linked to intracellular signaling elements of the CD28 costimulatory molecule and CD3ζ. The aim of the mutation (IL13.E13K.R109K) was to enhance selectivity of the CAR for recognition and killing of IL13Rα2+ GBMs while sparing normal cells bearing the composite IL13Ra1/IL4Ra receptor. Results Our aim was partially realized with improved recognition of tumor and reduced but persisting activity against normal tissue IL13Rα1+ cells by the IL13.E13K.R109K CAR. We show that these IL13 dTcs were efficient in killing IL13Rα2+ glioma cell targets with abundant secretion of cytokines IL2 and IFNγ, and they displayed enhanced tumor-induced expansion versus control unmodified T cells in vitro. In an in vivo test with a human glioma xenograft model, single intracranial injections of IL13 dTc into tumor sites resulted in marked increases in animal survivals. Conclusions These data raise the possibility of immune targeting of diffusely invasive GBM cells either via dTc infusion into resection cavities to prevent GBM recurrence or via direct stereotactic injection of dTcs to suppress inoperable or recurrent tumors. Systemic administration of these IL13 dTc could be complicated by reaction against normal tissues expressing IL13Ra1.

DAP12-Based Activating Chimeric Antigen Receptor for NK Cell Tumor Immunotherapy

“…Limitations of this approach, such as HLA restriction or defective Ag presentation on tumor cells, and difficulties in raising sufficient numbers of tumorreactive native T cells from patients, can be solved by the use of genetically modified autologous T cells with tumor-peptide TCRs or CARs (56,57). So far, CARs have been designed for the redirection of T cells against various tumor Ags, such as CD30 on Hodgkin lymphoma cells (58), CEA on colorectal cancer cells (59), HER-2 on ovarian and breast cancer cells (60), TARP on prostate and breast cancer cells (61), and EGFRvIII and IL13R on glioblastoma cells (62)(63)(64). However, concern has been raised about genetically modified autoreactive T cells, which might cause undesirable side effects after infusion into patients.…”

CAR T Cells Targeting Podoplanin Reduce Orthotopic Glioblastomas in Mouse Brains

“…17). In addition, CAR-transduced T cells can migrate through the microvascular walls and penetrate tumors (14,16). Clinical trials are ongoing using CAR T-cell therapy against GBM targeting EGFRvIII and HER2 (18,19).…”

Maximizing Local Access to Therapeutic Deliveries in Glioblastoma. Part I: Targeted Cytotoxic Therapy

“…Expression of IL-13RA2 and EphA2 is partially overlapping; hence, the combined overexpression is ~90% in patients with GBM (31). IL-13RA2 and EphA2 are targets for multiple therapeutic approaches currently in the clinic or under preclinical evaluation (36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52). The first generation of an IL-13-based cytotoxin produced in our laboratory, which nonspecifically targeted IL-13RA2, demonstrated clinical efficacy in patients with recurrent GBM (13,(53)(54)(55).…”