Recognition of Glioma Stem Cells by Genetically Modified T Cells Targeting EGFRvIII and Development of Adoptive Cell Therapy for Glioma

Abstract

No curative treatment exists for glioblastoma, with median survival times of less than 2 years from diagnosis. As an approach to develop immune-based therapies for glioblastoma, we sought to target antigens expressed in glioma stem cells (GSCs). GSCs have multiple properties that make them significantly more representative of glioma tumors than established glioma cell lines. Epidermal growth factor receptor variant III (EGFRvIII) is the result of a novel tumor-specific gene rearrangement that produces a unique protein expressed in approximately 30% of gliomas, and is an ideal target for immunotherapy. Using PCR primers spanning the EGFRvIII-specific deletion, we found that this tumor-specific gene is expressed in three of three GCS lines. Based on the sequence information of seven EGFRvIII-specific monoclonal antibodies (mAbs), we assembled chimeric antigen receptors (CARs) and evaluated the ability of CAR-engineered T cells to recognize EGFRvIII. Three of these anti-EGFRvIII CAR-engineered T cells produced the effector cytokine, interferon-c, and lysed antigen-expressing target cells. We concentrated development on a CAR produced from human mAb 139, which specifically recognized GSC lines and glioma cell lines expressing mutant EGFRvIII, but not wild-type EGFR and did not recognize any normal human cell tested. Using the 139-based CAR, T cells from glioblastoma patients could be genetically engineered to recognize EGFRvIII-expressing tumors and could be expanded ex vivo to large numbers, and maintained their antitumor activity. Based on these observations, a c-retroviral vector expressing this EGFRvIII CAR was produced for clinical application.

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.…”

CD44v6-targeted T cells mediate potent antitumor effects against acute myeloid leukemia and multiple myeloma

“…Even so, translating the results obtained in B-cell malignancies to other tumor types urgently awaits the validation of CAR targets different from B cell-lineage antigens. Clinical programs are currently investigating CAR redirection against already known mAb targets, including CD30 in Hodgkin lymphoma, 17 HER2 in solid 18 and brain tumors, 19 the vascular endothelial growth factor-2 in melanoma and renal cell carcinoma, 20 endothelial growth factor in glioma, 21 and mesothelin in mesothelioma. 22 Despite intense preclinical research on innovative targets, 23,24 developing CARs for multiple, rather than single, tumor types would be preferable.…”

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].…”