A herceptin-based chimeric antigen receptor with modified signaling domains leads to enhanced survival of transduced T lymphocytes and antitumor activity.
ABSTRACT: To generate chimeric Ag receptors (CARs) for the adoptive immunotherapy of cancer patients with ErbB2-expressing tumors, a single-chain Ab derived from the humanized mAb 4D5 Herceptin (trastuzumab) was initially linked to T cell signaling domains derived from CD28 and the CD3zeta to generate a CAR against ErbB2. Human PBLs expressing the 4D5 CAR demonstrated Ag-specific activities against ErbB2(+) tumors. However, a gradual loss of transgene expression was noted for PBLs transduced with this 4D5 CAR. When the CD3zeta signaling domain of the CAR was truncated or mutated, loss of CAR expression was not observed, suggesting that the CD3zeta signaling caused the transgene decrease, which was supported by the finding that T cells expressing 4D5 CARs with CD3zeta ITAM mutations were less prone to apoptosis. By adding 4-1BB cytoplasmic domains to the CD28-CD3zeta signaling moieties, we found increased transgene persistence in 4D5 CAR-transduced PBLs. Furthermore, constructs with 4-1BB sequences demonstrated increased cytokine secretion and lytic activity in 4D5 CAR-transduced T cells. More importantly, PBLs expressing this new version of the 4D5 CAR could not only efficiently lyse the autologous fresh tumor digests, but they could strongly suppress tumor growth in a xenogenic mouse model.
Project description:In this data set we include expression data from human CD4+ T cells isolated on day 0, 6, 11 and 24 follow anti-CD3/anti-CD28 magnetic bead stimulation and chimeric antigen receptor transduction. 30 samples were submitted. Samples represented three biological replicates of normal donors transduced with various CARs. CARs used were a cMet 28z specific CAR comprised of the IgG4 hinge, CD28 transmembrane and CD28 and CD3zeta intracellular domains. A CD19 CD28 CAR was specific to CD19, and was comprised of a CD8a hinge, CD28 transmembrane and CD28 and CD3zeta intracellular domain. A third CAR, the CD19 BBz, was used that was specific to CD19 was comprised of a CD8a hinge, CD8a transmembrane and 4-1BB and CD3zeta intracellular domains. Expression data was analyzied on day 0, 6, 11 and 24.
Project description:Adoptive transfer of tumor infiltrating or circulating lymphocytes transduced with tumor antigen receptors has been examined in various clinical trials to treat human cancers. The tumor antigens targeted by transferred lymphocytes affects the efficacy of this therapeutic approach. Because cancer stem cells (CSCs) play an important role in tumor growth and metastasis, we hypothesized that adoptive transfer of T cells targeting a CSC antigen could result in dramatic anti-tumor effects.An EpCAM-specific chimeric antigen receptor (CAR) was constructed to transduce human peripheral blood lymphocytes (PBLs) and thereby enable them to target the CSC marker EpCAM. To investigate the therapeutic capabilities of PBLs expressing EpCAM-specific CARs, we used two different tumor models, PC3, the human prostate cancer cell line, which has low expression levels of EpCAM, and PC3M, a highly metastatic clone of PC3 that has high expression levels of EpCAM. We demonstrate that CAR-expressing PBLs can kill PC3M tumor cells in vitro and in vivo. Despite the low expression of EpCAM on PC3 cells, CAR-expressing PBLs significantly inhibited tumor growth and prolonged mouse survival in a PC3 metastasis model, probably by targeting the highly proliferative and metastatic population of cancer cells.Our data demonstrate that PBLs expressing with EpCAM-specific CARs have significant anti-tumor activity against prostate cancer. Therefore, the adoptive transfer of T cells targeting EpCAM could have great potential as a cancer treatment.
Project description:In an attempt to treat cancer patients with ERBB2 overexpressing tumors, we developed a chimeric antigen receptor (CAR) based on the widely used humanized monoclonal antibody (mAb) Trastuzumab (Herceptin). An optimized CAR vector containing CD28, 4-1BB, and CD3zeta signaling moieties was assembled in a gamma-retroviral vector and used to transduce autologous peripheral blood lymphocytes (PBLs) from a patient with colon cancer metastatic to the lungs and liver, refractory to multiple standard treatments. The gene transfer efficiency into autologous T cells was 79% CAR(+) in CD3(+) cells and these cells demonstrated high-specific reactivity in in vitro coculture assays. Following completion of nonmyeloablative conditioning, the patient received 10(10) cells intravenously. Within 15 minutes after cell infusion the patient experienced respiratory distress, and displayed a dramatic pulmonary infiltrate on chest X-ray. She was intubated and despite intensive medical intervention the patient died 5 days after treatment. Serum samples after cell infusion showed marked increases in interferon-gamma (IFN-gamma), granulocyte macrophage-colony stimulating factor (GM-CSF), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and IL-10, consistent with a cytokine storm. We speculate that the large number of administered cells localized to the lung immediately following infusion and were triggered to release cytokine by the recognition of low levels of ERBB2 on lung epithelial cells.
Project description:The efficacy of T cells expressing chimeric antigen receptors (CARs) for solid tumors has been limited by insufficient CAR T cell expansion and persistence. The use of virus-specific T cells (VSTs) as carriers for CARs may overcome this limitation since CAR-VSTs can be boosted by viral vaccines or oncolytic viruses. However, there is limited understanding of the optimal combination of endodomains and their influence on the native T cell receptor (TCR) in VSTs. We therefore compared the function of GD2.CARs expressing the TCR zeta chain (?) alone or combined with endodomains from CD28 and 4-1BB in varicella zoster virus-specific (VZV) T cells. VZVSTs expressing GD2-CARs recognized VZV-derived peptides and killed GD2-expressing tumor cells. However, after repeated stimulation through their native TCR, the expansion of GD2-CAR.CD28?-VZVSTs was 3.3-fold greater (p < 0.001) than non-transduced VZVSTs, whereas GD2-CAR?- and GD2-CAR.41BB? inhibited VZVST expansion (p < 0.01). Compared to control VZVSTs, GD2-CAR.? VZVSTs showed a greater frequency of apoptotic (p < 0.01) T cells, whereas prolonged downregulation of the native ?? TCR was observed in GD2-CAR.41BB? VZVSTs (p < 0.001). We confirmed that CD28? can best maintain TCR function by expressing GD2.CARs in Epstein-Barr virus-specific T cells and CD19-CARs in VZVSTs. In response to CAR stimulation VSTs with CD28? endodomains also showed the greatest expansion (6 fold > GD2-CAR.41BB? VZVSTs (p < 0.001), however anti-tumor efficacy was superior in GD2-CAR.41BB?-VZVSTs. These findings demonstrate that CAR signaling domains can enhance or diminish the function of the native TCR and indicate that only CD28? may preserve the function of the native TCR in tonically signaling CAR-VSTs.
Project description:Successful tumor eradication by chimeric antigen receptor-expressing (CAR-expressing) T lymphocytes depends on CAR T cell persistence and effector function. We hypothesized that CD4+ and CD8+ T cells may exhibit distinct persistence and effector phenotypes, depending on the identity of specific intracellular signaling domains (ICDs) used to generate the CAR. First, we demonstrate that the ICOS ICD dramatically enhanced the in vivo persistence of CAR-expressing CD4+ T cells that, in turn, increased the persistence of CD8+ T cells expressing either CD28- or 4-1BB-based CARs. These data indicate that persistence of CD8+ T cells was highly dependent on a helper effect provided by the ICD used to redirect CD4+ T cells. Second, we discovered that combining ICOS and 4-1BB ICDs in a third-generation CAR displayed superior antitumor effects and increased persistence in vivo. Interestingly, we found that the membrane-proximal ICD displayed a dominant effect over the distal domain in third-generation CARs. The optimal antitumor and persistence benefits observed in third-generation ICOSBBz CAR T cells required the ICOS ICD to be positioned proximal to the cell membrane and linked to the ICOS transmembrane domain. Thus, CARs with ICOS and 4-1BB ICD demonstrate increased efficacy in solid tumor models over our current 4-1BB-based CAR and are promising therapeutics for clinical testing.
Project description:Chimeric antigen receptor (CAR)-expressing T cells targeting B-cell maturation antigen (BCMA) have activity against multiple myeloma, but improvements in anti-BCMA CARs are needed. We demonstrated recipient anti-CAR T-cell responses against a murine single-chain variable fragment (scFv) used clinically in anti-BCMA CARs. To bypass potential anti-CAR immunogenicity and to reduce CAR binding domain size, here we designed CARs with antigen-recognition domains consisting of only a fully human heavy-chain variable domain without a light-chain domain. A CAR designated FHVH33-CD8BBZ contains a fully human heavy-chain variable domain (FHVH) plus 4-1BB and CD3? domains. T cells expressing FHVH33-CD8BBZ exhibit similar cytokine release, degranulation, and mouse tumor eradication as a CAR that is identical except for substitution of a scFv for FHVH33. Inclusion of 4-1BB is critical for reducing activation-induced cell death and promoting survival of T cells expressing FHVH33-containing CARs. Our results indicate that heavy-chain-only anti-BCMA CARs are suitable for evaluation in a clinical trial.
Project description:Human cytomegalovirus (HCMV) reactivations are associated with lower overall survival after transplantations. Adoptive transfer of HCMV-reactive expanded or selected T cells can be applied as a compassionate use, but requires that the human leukocyte antigen-matched donor provides memory cells against HCMV. To overcome this, we developed engineered T cells expressing chimeric antigen receptors (CARs) targeted against the HCMV glycoprotein B (gB) expressed upon viral reactivation. Single-chain variable fragments (scFvs) derived from a human high-affinity gB-specific neutralizing monoclonal antibody (SM5-1) were fused to CARs with 4-1BB (BBL) or CD28 (28S) costimulatory domains and subcloned into retroviral vectors. CD4+ and CD8+ T cells obtained from HCMV-seronegative adult blood or cord blood (CB) transduced with the vectors efficiently expressed the gB-CARs. The specificity and potency of gB-CAR-T cells were demonstrated and compared in vitro using the following: 293T cells expressing gB, and with mesenchymal stem cells infected with a HCMV TB40 strain expressing Gaussia luciferase (HCMV/GLuc). BBL-gB-CAR-T cells generated with adult or CB demonstrated significantly higher in vitro activation and cytotoxicity performance than 28-gB-CAR-T cells. Nod.Rag.Gamma (NRG) mice transplanted with human CB CD34+ cells with long-term human immune reconstitution were used to model HCMV/GLuc infection in vivo by optical imaging analyses. One week after administration, response to BBL-gB-CAR-T cell therapy was observed for 5/8 mice, defined by significant reduction of the bioluminescent signal in relation to untreated controls. Response to therapy was sporadically associated with CAR detection in spleen. Thus, exploring scFv derived from the high-affinity gB-antibody SM5-1 and the 4-1BB signaling domain for CAR design enabled an in vitro high on-target effect and cytotoxicity and encouraging results in vivo. Therefore, gB-CAR-T cells can be a future clinical option for treatment of HCMV reactivations, particularly when memory T cells from the donors are not available.
Project description:T cells engineered to express CD19-specific chimeric antigen receptors (CARs) have shown breakthrough clinical successes in patients with B-cell lymphoid malignancies. However, similar therapeutic efficacy of CAR T cells in solid tumors is yet to be achieved. In this study we systematically evaluated a series of CAR constructs targeting glypican-3 (GPC3), which is selectively expressed on several solid tumors. We compared GPC3-specific CARs that encoded CD3? (Gz) alone or with costimulatory domains derived from CD28 (G28z), 4-1BB (GBBz), or CD28 and 4-1BB (G28BBz). All GPC3-CARs rendered T cells highly cytotoxic to GPC3-positive hepatocellular carcinoma, hepatoblastoma, and malignant rhabdoid tumor cell lines in vitro. GBBz induced the preferential production of Th1 cytokines (interferon ?/granulocyte macrophage colony-stimulating factor) while G28z preferentially induced Th2 cytokines (interleukin-4/interleukin-10). Inclusion of 4-1BB in G28BBz could only partially ameliorate the Th2-polarizing effect of CD28. 4-1BB induced superior expansion of CAR T cells in vitro and in vivo. T cells expressing GPC3-CARs incorporating CD28, 4-1BB, or both induced sustained tumor regressions in two xenogeneic tumor models. Thus, GBBz CAR endows T cells with superior proliferative potential, potent antitumor activity, and a Th1-biased cytokine profile, justifying further clinical development of GBBz CAR for immunotherapy of GPC3-positive solid tumors.
Project description:Chimeric antigen receptors (CARs) can redirect T cells against antigen-expressing tumors in an HLA-independent manner. To date, various CARs have been constructed using mouse single chain antibody variable fragments (scFvs) of high affinity that are immunogenic in humans and have the potential to mediate "on-target" toxicity. Here, we developed and evaluated a fully human CAR comprised of the human C4 folate receptor-alpha (?FR)-specific scFv coupled to intracellular T cell signaling domains. Human T cells transduced to express the C4 CAR specifically secreted proinflammatory cytokine and exerted cytolytic functions when cultured with ?FR-expressing tumors in vitro. Adoptive transfer of C4 CAR T cells mediated the regression of large, established human ovarian cancer in a xenogeneic mouse model. Relative to a murine MOv19 scFv-based ?FR CAR, C4 CAR T cells mediated comparable cytotoxic tumor activity in vitro and in vivo but had lower affinity for ?FR protein and exhibited reduced recognition of normal cells expressing low levels of ?FR. Thus, T cells expressing a fully human CAR of intermediate affinity can efficiently kill antigen-expressing tumors in vitro and in vivo and may overcome issues of transgene immunogenicity and "on-target off-tumor" toxicity that plague trials utilizing CARs containing mouse-derived, high affinity scFvs.