Project description:Chimeric antigen receptor (CAR) T cell therapy faces notable limitations in treatment of solid tumors. The suppressive tumor microenvironment (TME), characterized by complex interactions among immune and stromal cells, is gaining recognition in conferring resistance to CAR T cell therapy. Despite the abundance and diversity of macrophages in the TME, their intricate involvement in modulating responses to CAR T cell therapies remains poorly understood. Here, we conducted single-cell RNA sequencing (scRNA-seq) on tumors from 41 glioma patients undergoing IL13Rα2-targeted CAR T cell therapy, identifying elevated suppressive SPP-1 signatures predominantly in macrophages from patients who were resistant to treatment. Further integrative scRNA-seq analysis of high-grade gliomas (HGG)s and an interferon-signaling deficient syngeneic mouse model—both resistant to CAR T therapy—demonstrated the role of congruent suppressive pathways in mediating resistance to CAR T cells and a dominant role for SPP1+ macrophages. SPP1 blockade with an anti-SPP1 antibody prior to CAR T cell therapy abrogates the suppressive effects and substantially prolongs survival in IFN signaling-deficient as well as GBM syngeneic resistance models to CAR T cell therapy. These findings illuminate the role of SPP1+ macrophages in fueling a suppressive TME and driving solid tumor resistance to CAR cell therapies. Targeting SPP1 may serve as a universal strategy to reprogram immune dynamics in solid tumors mitigating resistance to CAR T therapies.
Project description:Chimeric antigen receptor (CAR)-redirected T cell therapy often fails to control tumors in the long-term due to selecting cancer cells that down-regulated or lost CAR targeted antigen. To reprogram the functional capacities of CAR T cells, we inserted IL12 into the extracellular moiety of a CD28- CAR; both the CAR and IL12 were functional indicated by antigen-redirected activation and STAT4 phosphorylation, respectively. CD8+ T cells engineered with a IL12-CAR gained a so far not recognized NK cell-like RNA expression signature and a CD94+CD56+CD62Lhigh phenotype closely similar, but not identical, to NK and cytokine activated killer (CIK) cells. IL12-CAR T cells with specificity for CEA additionally acquired antigen-independent, HLA-E restricted cytotoxicity eliminating both CEA-negative and CEA-positive cancer cells in an antigen-dependent and independent fashion that was in contrast to conventional CEA CAR T cells. Simultaneous signaling through CD3 of the CAR and through IL12 were required and sufficient for inducing NK-like cytotoxicity. Overall, we present a prototype of a new family of CARs that harbor a cytokine integrated into the extracellular module in order to reprogram the functional capacities of CAR T cells towards augmented tumor recognition and elimination.
Project description:Chimeric antigen receptor (CAR) T cell therapy is a promising immunotherapy against cancer. Although there is a growing interest in other cell types, a comparison of CAR immune effector cells in challenging solid tumor contexts is lacking. Here, we compare mouse and human NKG2D-CAR expressing T cells, NK cells and macrophages against glioblastoma, the most aggressive primary brain tumor. In vitro we show that T cell cancer killing is CAR-dependent, whereas intrinsic cytotoxicity overrules CAR-dependence for NK cells and CAR macrophages reduce glioma cells in co-culture assays. In orthotopic immunocompetent glioma mouse models, systemically administered CAR T cells demonstrate superior accumulation in the tumor and each immune cell type induces distinct changes in the tumor microenvironment. An otherwise low therapeutic efficacy is significantly enhanced by co-expression of pro-inflammatory cytokines in all CAR immune effector cells, underscoring the necessity for multifaceted cell engineering strategies to overcome the immunosuppressive solid tumor microenvironment.
Project description:Chimeric antigen receptor (CAR)-T cell therapies have shown great success in treating hematologic malignancies. Nonetheless, their therapeutic effect on solid tumors remains to be improved. Recently, macrophages have attracted great attention, given their ability to infiltrate solid tumors, phagocytize tumor cells as well as their immunomodulatory capacities. The first generation of CD3ζ-based CAR-macrophages demonstrated that the CAR could stimulate macrophage phagocytosis in a tumor antigen-dependent way. Here, we genetically engineered induced pluripotent stem cell (iPSC)-derived macrophages (iMACs) with TLR4 intracellular TIR domain-containing CARs against EGFRvIII and GPC3, which yielded markedly enhanced antitumor effect in two different solid tumor models including glioblastoma, and hepatocellular carcinoma in which complete remission was achieved with CAR-iMACs alone or in combination with CD47 antibody. Moreover, the tandem CD3ζ-TIR-CAR, or the “second-generation” design of TIR-based dual signaling CAR, endowed iMACs with both target engulfment/efferocytosis capacity against antigen-expressing solid tumor cells, and potency of antigen-dependent M1 state polarization and M2 state resistance in an NF-κB dependent manner. We also illustrated a surprising mechanism of tumor cell elimination by CAR-induced efferocytosis against tumor cell apoptotic bodies. Taken together, we established the next generation CAR-iMACs equipped with orthogonal phagocytosis and polarization capacity for better antitumor functions in treating solid tumors.
Project description:Anti-cancer immunotherapy approaches are increasingly coveted. Chimeric antigen receptor (CAR)-T cell therapy has been shown to be an effective treatment for hematological tumors, but the treatment of solid tumors still lacks effectiveness, due to lower intra-tumor infiltration of CAR-T cells and tumor-induced immunosuppression. Macrophages represent a very large proportion of the tumor environment, participate in many aspects to tumor development and therefore represent interesting therapeutic targets. Macrophages can infiltrate solid tumor tissue and interact with almost all cellular components in the tumor microenvironment. In addition, macrophages can also promote a direct anti-tumor response by phagocyting tumor cells. We have developed macrophages expressing a CAR receptor against the HER2 antigen. The CAR receptor possesses an intracellular domain CD3ζ having homology with the protein FcεRI-γ, which once activated by the recognition antibody-antigen, induces the phagocytic activity of macrophages. 72% of macrophages express the CAR after transduction. CAR-M can specifically phagocyte HER2 coated-beads in a much more effective way than WT macrophages. We have then confirmed the capacity of CAR-M to phagocyte HER2+ cancer cell lines. Co-culture of CAR-M with breast cancer tumoroids (HER2+ or HER2-) has also been performed demonstrating their efficacy in a more complex environment. However, in the tumor microenvironment, due to their plasticity, macrophages tend to adopt an anti-inflammatory phenotype losing their anti-tumor activities. We have therefore developed a combined strategy by inhibiting two proprotein convertases, Furin and PC1/3 in CAR-M. The inhibition of furin or PC1/3 induces an increase in pro-inflammatory markers and maintains macrophage activation in the presence of cancer cells. In addition, HER2+ CAR-M with shFurin or shPC1/3 greatly increases the phagocytic activity on Her2+ beads or Her2+ tumors. These enzymes are therefore phenotypic regulators of macrophages. Our strategy is therefore based on a double activation of tumor-infiltrating macrophages. The first one consists in boosting the phagocytic activity of macrophages by having them express a CAR receptor targeting a tumor antigen. The second allows their reprogramming towards a pro- inflammatory phenotype by the inhibition of Furin and/or PC1/3 proprotein convertases
Project description:A significant challenge for chimeric antigen receptor (CAR) T cell therapy against glioblastoma (GBM) is its immunosuppressive tumor microenvironment (TME), which is densely populated and supported by protumoral glioma-associated microglia and macrophages (GAMs). Targeting CD47, a don't-eat-me signal overexpressed by tumor cells, disrupts the CD47-SIRPalpha axis and induces GAM phagocytic function. However, antibody-mediated CD47 blockade monotherapy is associated with toxicity and low bioavailability in solid tumors. To overcome these limitations, we combined local CAR T cell therapy with paracrine GAM modulation to effectively eliminate GBM. To this end, we engineered a new CAR T cell against epidermal growth factor receptor variant III (EGFRvIII) that constitutively secretes a signal regulatory protein gamma (SIRPgamma)-related protein (SGRP) with high affinity to CD47. Anti-EGFRvIII-SGRP CAR T cells eliminated EGFRvIII+ GBM in a dose-dependent manner in vitro and eradicated orthotopically xenografted EGFRvIII-mosaic GBM by locoregional application in vivo. This resulted in significant tumor-free long-term survival, followed by partial tumor control upon tumor re-challenge. Combining anti-CD47 antibodies with anti-EGFRvIII CAR T cells failed to achieve a similar therapeutic effect, underscoring the importance of sustained paracrine GAM modulation. Multidimensional brain immunofluorescence microscopy and in-depth spectral flow cytometry on GBM-xenografted brains showed that anti-EGFRvIII-SGRP CAR T cells accelerated GBM clearance, increased CD68+ cell trafficking to tumor scar sites and promoted GAM-mediated tumor cell uptake. In a peripheral lymphoma mouse xenograft model, anti-CD19-SGRP CAR T cells had superior efficacy to conventional anti-CD19 CAR T cells. Validation on human GBM explants revealed that anti-EGFRvIII-SGRP CAR T cells had a similar tumor-killing capacity to anti-EGFRvIII CAR monotherapy but showed a slight improvement in the maintenance of tumor-infiltrated CD14+ cells. Thus, local anti-EGFRvIII-SGRP CAR T cell therapy combines the potent antitumor effect of engineered T cells with the modulation of the surrounding innate immune TME. This results in the additive elimination of bystander EGFRvIII- tumor cells in a manner that overcomes the main mechanisms of CAR T cell therapy resistance, including tumor innate immune suppression and antigen escape.
Project description:Chimeric antigen receptor (CAR)-T cell therapy has shown promise in treating CD19+ hematological tumors, but some patients fail to respond. Here we used an immune-competent mouse model of B cell acute lymphoblastic leukemia (B-ALL) to assess clonal tumor populations with distinct responses to CAR-T cell therapy. We identified GPR65 as a determinant of tumor responsiveness to CAR-T cell therapy, with high GPR65 expression associated with a complete response. GPR65 KO tumors were resistant to CAR-T treatment in vivo. This was associated with increased tumor VEGFA expression driven by FOXO1 activation and expanded host macrophages. Either depletion of host macrophages or deletion of VEGFA from GPR65 KO tumors restored responsiveness to CAR-T cell treatment. Anti-VEGFa therapy, in combination with CD19-CAR-T, prolongs the survival of GPR65-KO tumor-bearing mice in pre-clinical models. Our results indicate that GPR65 may be a useful biomarker for tumor responsiveness to CAR-T cell therapy and further suggest VEGFA or host macrophages as therapeutic targets to improve CAR-T efficacy.
Project description:Chimeric antigen receptor (CAR)-T cell therapy has shown promise in treating CD19+ hematological tumors, but some patients fail to respond. Here we used an immune-competent mouse model of B cell acute lymphoblastic leukemia (B-ALL) to assess clonal tumor populations with distinct responses to CAR-T cell therapy. We identified GPR65 as a determinant of tumor responsiveness to CAR-T cell therapy, with high GPR65 expression associated with a complete response. GPR65 KO tumors were resistant to CAR-T treatment in vivo. This was associated with increased tumor VEGFA expression driven by FOXO1 activation and expanded host macrophages. Either depletion of host macrophages or deletion of VEGFA from GPR65 KO tumors restored responsiveness to CAR-T cell treatment. Anti-VEGFa therapy, in combination with CD19-CAR-T, prolongs the survival of GPR65-KO tumor-bearing mice in pre-clinical models. Our results indicate that GPR65 may be a useful biomarker for tumor responsiveness to CAR-T cell therapy and further suggest VEGFA or host macrophages as therapeutic targets to improve CAR-T efficacy.