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:Chimeric antigen receptor T cells (CAR-T) therapy has not yet been fully explored in solid tumors. Human epidermal growth factor receptor-2(HER2) is widely expressed in cancers. Investigators have developed anti-HER2 CAR-modified T cells and validated the efficiency targeting HER2-positive cancer in preclinical studies. This study is aimed to confirm its adverse effects including cytokine storm response and any other adverse effects. In addition, CAR-T cells persistence, tumor elimination and disease status after treatment will be evaluated.
Project description:Immunotherapy is a revolution in cancer treatment. Despite its success, cancer patients eventually progress due to the emergence of resistance. In this scenario, the selection of the tumor antigen is important and can be decisive in the success of the clinical response, particularly when resistance emerge. T cell bispecific antibodies (TCBs) are engineered molecules that include, within a single entity, binding sites to the T cell receptor and to a tumor-specific or a tumor-associated antigen. It is assumed that, as all TCBs have the same mechanism of action, mechanisms of resistance are independent of the tumor antigen. Using gastric CEA+/HER2+ MKN45 cells as a model and TCBs directed against CEA or HER2, here we show that the mechanism of resistance to a T cell-based therapy is dependent on the tumor antigen. Acquired resistant models to a high-affinity CEA-targeted TCB exhibit a reduction of CEA antigen levels due to transcriptional silencing, which is reversible upon 5-AZA treatment in vitro and in vivo. In contrast, a HER2-TCB resistant model maintains HER2 levels as HER2 downregulation led to an impairment of proliferation. Furthermore, using this latter model, we identify the disruption of the interferon-gamma signaling as the cause of resistance to killing by active T lymphocytes. Our results unveil different mechanisms of acquired resistance to TCBs depending on the selected antigen, which will help in the design of combinatorial strategies to increase the efficacy of cancer immunotherapies and to anticipate and overcome resistances.
Project description:Chimeric Antigen Receptor (CAR) T cell therapy has shown promise in treating hematologic malignancies. However, it is limited to individualized cell therapy and faces challenges, including high costs, extended preparation time, and limited efficacy against solid tumors. Here, we generated circular RNAs (circRNAs) encoding Chimeric Antigen Receptor (CAR) transmembrane proteins, referred to as circRNACAR, which mediated remarkable tumor killing in both T cells and macrophages. In addition, macrophages exhibited efficient phagocytosis of tumor cells and pro-inflammatory polarization induced by circRNACAR in vitro. We demonstrated that circRNACAR, delivered with immunocyte-tropic lipid nanoparticles (LNPs), significantly inhibited tumor growth, improved survival rates and induced a pro-inflammatory tumor microenvironment in mice. Importantly, the combination of circRNAAnti-HER2-CAR and circRNA-based cancer vaccines encoding the corresponding transmembrane HER2 antigen, termed circRNAHER2, exhibited synergistically enhanced anti-tumor activity. Notably, we found that circRNACAR could boost the level of circRNAHER2-elicited antibodies, which could mediate effective killing of HER2+ tumor cells by macrophages, indicating the potential of vaccination-elicited antibodies in developing novel immunotherapy. This proof-of-concept study demonstrated that the combination of circRNA-based in vivo CAR and vaccines, termed in vivo CAR-VAC, holds the potential to become an upgraded off-the-shelf immunotherapy, and also sheds light on the huge potential of vaccination-elicited antibodies in cancer immunotherapy.
Project description:Markers predicting response and resistance to chimeric antigen receptor (CAR) T cells in relapsed/refractory multiple myeloma are currently missing. We subjected cells isolated from peripheral blood and bone marrow before and after the application of CAR T cells directed against B cell maturation antigen to single cell multi-omic analyses to identify markers associated with resistance and early relapse.
Project description:Chimeric antigen receptor (CAR)-T cell-based therapies demonstrated remarkable efficacies for treating otherwise intractable cancers, particularly B-cell malignancies. However, existing FDA-approved CAR-Ts were limited by low antigen sensitivity, rendering their insufficient targeting to low antigen-expressing cancers. To improve the antigen sensitivity of CAR-Ts, we engineered CARs targeting CD19, CD22, and HER2 by including intrinsically disordered regions (IDRs) that promote signaling condensation. The CARs fused with IDR from FUS, EWS, or TAF15 triggered enhanced membrane-proximal signaling in the CAR-T synapse, which led to an increased release of cytotoxic factors, a higher killing activity towards low antigen-expressing cancer cells in vitro. Moreover, the IDR CAR-Ts induced improved anti-tumor effects in vivo in both blood cancer and solid tumor models. No elevated tonic signaling was observed in IDR CAR-Ts. Together, we demonstrated IDRs as a new tool set to enhance CAR-T cytotoxicity and to broaden CAR-T’s application to low antigen-expressing cancers.
Project description:Chimeric antigen receptor (CAR) T-cells induce responses in patients with relapsed/refractory leukemia; however, long-term efficacy is frequently limited by post-CAR relapses. The inability to target antigen-low cells is an intrinsic vulnerability of second-generation CAR T-cells and underlies the majority of relapses following CD22BBz CAR T-cell therapy. We interrogated CD22BBz CAR signaling in response to low antigen and found inefficient phosphorylation of LAT, limiting downstream signaling. To overcome this, we designed the Adjunctive LAT-Activating CAR T-cell (ALA-CART) platform, pairing a second-generation CAR with a LAT-CAR incorporating the intracellular domain of LAT. ALA-CART cells demonstrated reduced differentiation during manufacturing and increased LAT phosphorylation, MAPK signaling and AP-1 activity. Consequently, ALA-CART cells showed improved cytotoxicity, proliferation, persistence and efficacy against antigen-low leukemias that were refractory to clinically-active CD22BBz CAR T-cells. These data suggest restoration of LAT signaling through the ALA-CART platform represents a promising strategy for overcoming multiple mechanisms of CAR T-cell failure.
Project description:Resistance to chimeric antigen receptor (CAR) T cell therapy develops through multiple mechanisms including antigen-loss escape and tumor-induced immune suppression. Expression of multiple CARs may overcome multi-antigen-loss escape. Similarly, expression of switch receptors that convert inhibitory immune checkpoint signals into positive costimulatory signals may enhance CAR T cell activity in the tumor microenvironment. Engineering multiple features into one cell product, however, is limited by transgene packaging constraints of current vector systems. Here, we describe a leucine zipper-based cell sorting methodology that enables selective single-step immunomagnetic purification of cells co-transduced with two vectors, designed to potentially double the number of incorporated transgenes. This “Zip-sorting” system facilitated generation of T cells simultaneously expressing up to four CARs and co-expressing up to three switch receptors. These multi-CAR multi-Switch receptor arrays enabled T cells to eliminate antigenically heterogeneous syngeneic leukemia populations co-expressing multiple inhibitory ligands. Zip-sorted multi-CAR multi-Switch receptor T cells represent a combinatorial therapeutic strategy to overcome multiple mechanisms of CAR T cell resistance.