Combinatorial antigen recognition with balanced signaling promotes selective tumor eradication by engineered T cells

1] Center for Cell Engineering, Memorial Sloan-Kettering Cancer Center (MSKCC), New York, New York, USA. [2] Biochemistry, Cell, and Molecular Biology Program, Weill Cornell Graduate School for Medical Sciences, Cornell University, New York, New York, USA.
Nature Biotechnology (Impact Factor: 41.51). 12/2012; 31(1). DOI: 10.1038/nbt.2459
Source: PubMed

ABSTRACT Current T-cell engineering approaches redirect patient T cells to tumors by transducing them with antigen-specific T-cell receptors (TCRs) or chimeric antigen receptors (CARs) that target a single antigen. However, few truly tumor-specific antigens have been identified, and healthy tissues that express the targeted antigen may undergo T cell-mediated damage. Here we present a strategy to render T cells specific for a tumor in the absence of a truly tumor-restricted antigen. T cells are transduced with both a CAR that provides suboptimal activation upon binding of one antigen and a chimeric costimulatory receptor (CCR) that recognizes a second antigen. Using the prostate tumor antigens PSMA and PSCA, we show that co-transduced T cells destroy tumors that express both antigens but do not affect tumors expressing either antigen alone. This 'tumor-sensing' strategy may help broaden the applicability and avoid some of the side effects of targeted T-cell therapies.

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Available from: Michael Bachmann, Apr 01, 2014
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    • "In this regard, PSMA is physiologically expressed in kidney, nervous system glia, and small intestine [18], and the risk to damage these organs and structures cannot be excluded simply based on the fine target specificity demonstrated in an experimental setting by the novel mAb we used to design our CAR [19]. However, in a clinical scenario, this vector containing a bidirectional promoter could be exploited to address this safety issue, namely by driving the simultaneous expression of a CAR molecule and a “safety switch” suicide gene, such as an inducible caspase or the herpes simplex virus thymidine kinase (HSV-TK) [35], [42]; or alternatively a chimeric costimulatory receptor (CCR) for combinatorial antigen recognition [43]. "
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    ABSTRACT: Immunology-based interventions have been proposed as a promising curative chance to effectively attack postoperative minimal residual disease and distant metastatic localizations of prostate tumors. We developed a chimeric antigen receptor (CAR) construct targeting the human prostate-specific membrane antigen (hPSMA), based on a novel and high affinity specific mAb. As a transfer method, we employed last-generation lentiviral vectors (LV) carrying a synthetic bidirectional promoter capable of robust and coordinated expression of the CAR molecule, and a bioluminescent reporter gene to allow the tracking of transgenic T cells after in vivo adoptive transfer. Overall, we demonstrated that CAR-expressing LV efficiently transduced short-term activated PBMC, which in turn were readily stimulated to produce cytokines and to exert a relevant cytotoxic activity by engagement with PSMA+ prostate tumor cells. Upon in vivo transfer in tumor-bearing mice, CAR-transduced T cells were capable to completely eradicate a disseminated neoplasia in the majority of treated animals, thus supporting the translation of such approach in the clinical setting.
    PLoS ONE 10/2014; 9(10):e109427. DOI:10.1371/journal.pone.0109427 · 3.23 Impact Factor
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    • "Alternatively, the generation of target lists, such as we present here may be exploited in the future when a new generation of immunotherapeutic agents where more than one set of antigens is required to fully activate an effector T-cell-can be developed. The creation of a treatment strategy for prostate cancer that requires recognition of both PMSA and PSCA to fully trigger a dual-engineered T-cell population may be one such approach (70). Our next step will be to validate surface expression of the transcripts described here by flow cytometry, and thus complement gene expression data with the demonstrated presence of protein that could be targeted on the surface of pediatric T-ALL. "
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    ABSTRACT: Pediatric lymphoid leukemia has the highest cure rate of all pediatric malignancies, yet due to its prevalence, still accounts for the majority of childhood cancer deaths and requires long-term highly toxic therapy. The ability to target B-cell ALL with immunoglobulin-like binders, whether anti-CD22 antibody or anti-CD19 CAR-Ts, has impacted treatment options for some patients. The development of new ways to target B-cell antigens continues at rapid pace. T-cell ALL accounts for up to 20% of childhood leukemia but has yet to see a set of high-value immunotherapeutic targets identified. To find new targets for T-ALL immunotherapy, we employed a bioinformatic comparison to broad normal tissue arrays, hematopoietic stem cells (HSC), and mature lymphocytes, then filtered the results for transcripts encoding plasma membrane proteins. T-ALL bears a core T-cell signature and transcripts encoding TCR/CD3 components and canonical markers of T-cell development predominate, especially when comparison was made to normal tissue or HSC. However, when comparison to mature lymphocytes was also undertaken, we identified two antigens that may drive, or be associated with leukemogenesis; TALLA-1 and hedgehog interacting protein. In addition, TCR subfamilies, CD1, activation and adhesion markers, membrane-organizing molecules, and receptors linked to metabolism and inflammation were also identified. Of these, only CD52, CD37, and CD98 are currently being targeted clinically. This work provides a set of targets to be considered for future development of immunotherapies for T-ALL.
    Frontiers in Oncology 06/2014; 4:134. DOI:10.3389/fonc.2014.00134
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    • "For a long time the lack of truly tumor-specific antigens has limited the application of genetically engineered T lymphocytes to certain cancer types. Recently it has been demonstrated, that the risk of unwanted “on target, off side” effects in case target antigens are not exclusively restricted to tumor tissues can be circumvented by balanced combination of activating and costimulatory CARs with independent antigen-specificities [44]. Thus, the door is now open to target a broad spectrum of different cancers lacking exclusively tumor-specific antigens with CAR modified T cells in future. "
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    ABSTRACT: Genetically engineered T lymphocytes are a promising option for cancer therapy. Prior to adoptive transfer they have to be expanded in vitro to reach therapeutically sufficient numbers. So far, no universal method exists for selective in vitro expansion of engineered T lymphocytes. In order to overcome this problem and for proof of concept we incorporated a novel unique peptide sequence of ten amino acids as epitope (E-Tag) into the binding domains of two novel chimeric antigen receptors (ECARs) directed against either prostate stem cell antigen (PSCA) for the treatment of prostate cancer (PCa) or CD33 for the treatment of acute myeloide leukemia (AML). The epitope tag then was utilized for expanding ECAR engrafted T cells by triggering the modified T cells via a monoclonal antibody directed against the E-Tag (Emab). Moreover, the E-Tag served as an efficient selection epitope for immunomagnetic isolation of modified T cells to high purity. ECAR engrafted T cells were fully functional and mediated profound anti-tumor effects in the respective models of PCa or AML both in vitro and in vivo. The method can be integrated straightforward into clinical protocols to improve therapeutic efficiency of tumor treatment with CAR modified T lymphocytes.
    PLoS ONE 04/2014; 9(4):e93745. DOI:10.1371/journal.pone.0093745 · 3.23 Impact Factor
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