CD19.CAR T Cells(University Hospital Heidelberg)

Resistance to genotoxic therapies and tumor recurrence are hallmarks of glioblastoma (GBM), an aggressive brain tumor. In this study, we investigated functional drivers of post-treatment recurrent GBM through integrative genomic analyses, genome-wide genetic perturbation screens in patient-derived GBM models and independent lines of validation. Specific genetic dependencies were found consistent across recurrent tumor models, accompanied by increased mutational burden and differential transcript and protein expression compared to its primary GBM predecessor. Our observations suggest a multi-layered genetic response to drive tumor recurrence and implicate PTP4A2 (protein tyrosine phosphatase 4A2) as a modulator of self-renewal, proliferation and tumorigenicity in recurrent GBM. Genetic perturbation or small-molecule inhibition of PTP4A2 acts through a dephosphorylation axis with roundabout guidance receptor 1 (ROBO1) and its downstream molecular players, exploiting a functional dependency on ROBO signaling. Because a pan-PTP4A inhibitor was limited by poor penetrance across the blood-brain barrier in vivo, we engineered a second-generation chimeric antigen receptor (CAR) T cell therapy against ROBO1, a cell surface receptor enriched across recurrent GBM specimens. A single dose of ROBO1-targeted CAR T cells doubled median survival in cell-line-derived xenograft (CDX) models of recurrent GBM. Moreover, in CDX models of adult lung-to-brain metastases and pediatric relapsed medulloblastoma, ROBO1 CAR T cells eradicated tumors in 50-100% of mice. Our study identifies a promising multi-targetable PTP4A-ROBO1 signaling axis that drives tumorigenicity in recurrent GBM, with potential in other malignant brain tumors.

CD19 chimeric antigen receptor T (CD19CAR-T) cells have achieved promising outcomes in relapsed/refractory B cell malignancies. However, recurrences occur due to the loss of CAR-T cell persistence. We developed dual T/B cell co-stimulatory molecules (CD28 and CD40) in CAR-T cells to enhance intense tumoricidal activity and persistence. CD19.28.40z CAR-T cells promoted pNF-κB and pRelB downstream signaling while diminishing NFAT signaling upon antigen exposure. CD19.28.40z CAR-T cells demonstrated greater proliferation, which translated into effective anti-tumor cytotoxicity in long-term co-culture assay. Repetitive weekly antigen stimulation unveiled continuous CAR-T cell expansion while preserving central memory T cell subset and lower expression of exhaustion phenotypes. The intrinsic genes underlying CD19.28.40z CAR-T cell responses were compared with conventional CARs and demonstrated the up-regulated genes associated with T cell proliferation and memory as well as down-regulated genes related to apoptosis, exhaustion, and glycolysis pathway. Enrichment of genes toward T cell stemness, particularly SELL, IL-7r, TCF7, and KLF2, was observed. Effective and continuing anti-tumor cytotoxicity in vivo was exhibited in both B cell lymphoblastic leukemia and B cell non-Hodgkin lymphoma xenograft models while demonstrating persistent T cell memory signatures. The functional enhancement of CD37.28.40z CAR-T cell activities against CD37⁺ tumor cells was further validated. The modification of dual T/B cell signaling molecules remarkably maximized the efficacy of CAR-T cell therapy.