Patient-derived glioblastoma stem cells are killed by CD133-specific CAR T cells but induce the T cell aging marker CD57

Abstract

The AC133 epitope of CD133 is a cancer stem cell (CSC) marker for many tumor entities, including the highly malignant glioblastoma multiforme (GBM). We have developed an AC133-specific chimeric antigen receptor (CAR) and show that AC133-CAR T cells kill AC133+ GBM stem cells (GBM-SCs) both in vitro and in an orthotopic tumor model in vivo. Direct contact with patient-derived GBM-SCs caused rapid upregulation of CD57 on the CAR T cells, a molecule known to mark terminally or near-terminally differentiated T cells. However, other changes associated with terminal T cell differentiation could not be readily detected. CD57 is also expressed on tumor cells of neural crest origin and has been preferentially found on highly aggressive, undifferentiated, multipotent CSC-like cells. We found that CD57 was upregulated on activated T cells only upon contact with CD57+ patient-derived GBM-SCs, but not with conventional CD57-negative glioma lines. However, CD57 was not downregulated on the GBM-SCs upon their differentiation, indicating that this molecule is not a bona fide CSC marker for GBM. Differentiated GBM cells still induced CD57 on CAR T cells and other activated T cells. Therefore, CD57 can apparently be upregulated on activated human T cells by mere contact with CD57+ target cells.

Nucleofection with Plasmid DNA for CRISPR/Cas9-Mediated Inactivation of Programmed Cell Death Protein 1 in CD133-Specific CAR T Cells

“…28 In this study, simple models were used, including co-culture of CAR T cells with tumor cells in vitro and treatment of tumor-bearing immunodeficient mice with human CAR T cells, as used before. 14,20,29 Although a CD133 highly expressed U251 cell line cannot be a very suitable model to represent the patient situation, it was used to judge the CAR T cells' capability of killing tumors on a quantified level. Furthermore, though the tumor cells used expressed high levels of PD-L1, it is not clear whether the PD-1/ PD-L1 pathway is the main negative regulator of CAR T cells in the models.…”

CARTs for Solid Tumors: Feasible or Infeasible?

“…It is inserted between the binding domain and the transmembrane (TM) domain and is important for CAR expression on the cell surface [66]. The hinge region is usually derived from CD8, IgG1, or IgG4 molecules [30,[67][68][69][70]. It mediates flexibility of the scFV, and its length may influence the quality of the interaction between scFV and antigen, depending on the location of the epitope on the target antigen.…”

“…The TM domain is usually derived from CD3ζ [74], CD4 [75,76], CD8 [47,60,68], or CD28 [70,75,77] molecules and is inserted between the hinge region and the signaling endodomains. It has significant effects on the cell surface expression of CARs.…”

CARs on the Highway: Chimeric Antigen Receptor Modified T Cells for the Adoptive Cell Therapy of Malignant Diseases

“…CAR T cells are capable to eliminate those CSCs in experimental models including melanoma; one trial is going to explore the clinical efficacy [36][37][38][39][40].…”