Project description:In the past decade, chimeric antigen receptor (CAR)-T cell therapy has emerged as a promising immunotherapeutic approach for combating cancers, demonstrating remarkable efficacy in relapsed/refractory hematological malignancies in both pediatric and adult patients. CAR-natural killer (CAR-NK) cell complements CAR-T cell therapy by offering several distinct advantages. CAR-NK cells do not require HLA compatibility and exhibit low safety concerns. Moreover, CAR-NK cells are conducive to "off-the-shelf" therapeutics, providing significant logistic advantages over CAR-T cells. Both CAR-T and CAR-NK cells have shown consistent and promising results in hematological malignancies. However, their efficacy against solid tumors remains limited due to various obstacles including limited tumor trafficking and infiltration, as well as an immuno-suppressive tumor microenvironment. In this review, we discuss the recent advances and current challenges of CAR-T and CAR-NK cell immunotherapies, with a specific focus on the obstacles to their application in solid tumors. We also analyze in depth the advantages and drawbacks of CAR-NK cells compared to CAR-T cells and highlight CAR-NK CAR optimization. Finally, we explore future perspectives of these adoptive immunotherapies, highlighting the increasing contribution of cutting-edge biotechnological tools in shaping the next generation of cellular immunotherapy.
Project description:Clinical application of autologous chimeric antigen receptor (CAR)-T cells is complicated by limited targeting of cancer types, as well as the time-consuming and costly manufacturing process. We develop CD70-targeted, induced pluripotent stem cell-derived CAR-natural killer (NK) (70CAR-iNK) cells as an approach for universal immune cell therapy. Besides the CD70-targeted CAR molecule, 70CAR-iNK cells are modified with CD70 gene knockout, a high-affinity non-cleavable CD16 (hnCD16), and an interleukin (IL)-15 receptor α/IL-15 fusion protein (IL15RF). Multi-gene-edited 70CAR-iNK cells exhibit robust cytotoxicity against a wide range of tumors. In vivo xenograft models further demonstrate their potency in effectively targeting lymphoma and renal cancers. Furthermore, we find that recipient alloreactive T cells express high levels of CD70 and can be eliminated by 70CAR-iNK cells, leading to improved survival and persistence of iNK cells. With the capability of tumor targeting and the potential to eliminate alloreactive T cells, 70CAR-iNK cells are potent candidates for next-generation universal immune cell therapy.
Project description:CAR-T (chimeric antigen receptor T) cells have emerged as a milestone in the treatment of patients with refractory B-cell neoplasms. However, despite having unprecedented efficacy against hematological malignancies, the treatment is far from flawless. Its greatest drawbacks arise from a challenging and expensive production process, strict patient eligibility criteria and serious toxicity profile. One possible solution, supported by robust research, is the replacement of T lymphocytes with NK cells for CAR expression. NK cells seem to be an attractive vehicle for CAR expression as they can be derived from multiple sources and safely infused regardless of donor-patient matching, which greatly reduces the cost of the treatment. CAR-NK cells are known to be effective against hematological malignancies, and a growing number of preclinical findings indicate that they have activity against non-hematological neoplasms. Here, we present a thorough overview of the current state of knowledge regarding the use of CAR-NK cells in treating various solid tumors.
Project description:Colorectal carcinoma (CRC) presents a formidable medical challenge, demanding innovative therapeutic strategies. Chimeric antigen receptor (CAR) natural killer (NK) cell therapy has emerged as a promising alternative to CAR T-cell therapy for cancer. A suitable tumor antigen target on CRC is carcinoembryonic antigen (CEA), given its widespread expression and role in tumorigenesis and metastasis. CEA is known to be prolifically shed from tumor cells in a soluble form, thus hindering CAR recognition of tumors and migration through the TME. We have developed a next-generation CAR construct exclusively targeting cell-associated CEA, incorporating a PD1-checkpoint inhibitor and a CCR4 chemokine receptor to enhance homing and infiltration of the CAR-NK-92 cell line through the TME, and which does not induce fratricidal killing of CAR-NK-92-cells. To evaluate this therapeutic approach, we harnessed intricate 3D multicellular tumor spheroid models (MCTS), which emulate key elements of the TME. Our results demonstrate the effective cytotoxicity of CEA-CAR-NK-92 cells against CRC in colorectal cell lines and MCTS models. Importantly, minimal off-target activity against non-cancerous cell lines underscores the precision of this therapy. Furthermore, the integration of the CCR4 migration receptor augments homing by recognizing target ligands, CCL17 and CCL22. Notably, our CAR design results in no significant trogocytosis-induced fratricide. In summary, the proposed CEA-targeting CAR-NK cell therapy could offer a promising solution for CRC treatment, combining precision and efficacy in a tailored approach.
Project description:BackgroundColorectal cancer (CRC) is the third most common cancer worldwide, with highly variable prognosis and response to treatment. A large subset of patients does not respond to standard treatments or develops resistance. As an alternative, adoptive immunotherapy based on chimeric antigen receptor (CAR)-transduced immune cells has been proposed, however with significant adverse events. We therefore evaluated alternative CAR targets already tested in other tumour types and employed the natural killer cell line NK-92 for CAR transduction because of its more favourable toxicity profile.MethodsAs an alternative antigen, we considered mesothelin (MSLN), the most represented target in CAR-based clinical studies for solid tumours. MSLN RNA expression was analysed in large series of CRC tumours (n = 640) and cell lines (n = 150), to evaluate its distribution and to identify MSLN-overexpressing models. NK-92 cells were transduced with anti-MSLN CAR, and subsequently sorted and cloned. Activity of CAR-NK-92 cells against target-expressing ovarian and CRC cells was assessed in vitro and in vivo. Statistical significance of efficacy was evaluated by t-test and log-rank test.ResultsLarge-scale expression analysis highlighted that about 10% of CRCs overexpress MSLN at levels comparable to those of ovarian cancer, a typical target of MSLN-CAR-based therapy. Intriguingly, MSLN overexpression is more frequent in poor prognosis and KRAS/BRAF-mutant CRC. Lentiviral transduction of NK-92 cells with the MSLN-CAR, followed by sorting and cloning, led to the identification of one clone, MSLN.CAR.NK-92.cl45, stably expressing the CAR and retaining the NK phenotype. As expected, the clone demonstrated significant in vitro and in vivo activity against ovarian cancer cells. When repurposed against models of CRC expressing high MSLN levels, it displayed comparable efficacy, both in vitro and in vivo. Specificity of the clone was confirmed by the absence of activity on control models with low or absent MSLN.ConclusionsOur results provide preclinical evidence that a subset of colorectal cancers expressing high mesothelin levels can be effectively targeted by MSLN-CAR-based immunotherapy. The potential therapeutic impact of these findings is enhanced by the fact that frequently MSLN-overexpressing CRCs display worse prognosis and resistance to standard care.
Project description:Background/Objectives: Monoclonal antibody therapies for HER2-positive tumors frequently encounter resistance, requiring alternative treatment strategies. This study investigates the use of natural killer (NK) cells expressing HER2-specific chimeric antigen receptor (CAR) to address this issue. CAR NK cells have several benefits over CAR T cells: they are less likely to cause severe side effects such as cytokine release syndrome and neurotoxicity, can be sourced from various origins, and do not trigger Graft versus Host Disease, making them ideal for "off-the-shelf" applications. Methods: We have generated NK-92 cell lines expressing first, second and third-generation HER2-specific CARs with CD28 and/or 41BB costimulatory domains using a retroviral transduction system, followed by FACS sorting and expansion to obtain pure HER2-CAR NK-92 cell products for functional benchmarking. Results: In vitro tests showed that these CAR NK cells were effective against both trastuzumab-sensitive (CD44-) and -resistant (CD44+) tumors in monolayer cultures. However, in three-dimensional spheroid models and in vivo xenografts, they were less effective against CD44+ trastuzumab-resistant tumors. Conclusions: This reduced efficacy highlights the significant role of the tumor microenvironment, particularly the extracellular matrix, in hindering the therapeutic potential of CAR NK cells. Despite the promising in vitro performance of CAR NK cells, this study emphasizes the need for improved strategies to enhance their penetration and effectiveness in resistant tumors: optimizing CAR constructs and devising methods to overcome extracellular matrix barriers are crucial for advancing CAR NK cell therapies in oncology.
Project description:Despite the remarkable success of chimeric antigen receptor (CAR)-T cells against hematologic malignancies, severe off-tumor effects have constrained their use against solid tumors. Recently, CAR-engineered natural killer (NK) cells have emerged as an effective and safe alternative. Here, we demonstrate that HER2 CAR-expression in NK cells from healthy donors and patients with breast cancer potently enhances their anti-tumor functions against various HER2-expressing cancer cells, regardless of MHC class I expression. Moreover, HER2 CAR-NK cells exert higher cytotoxicity than donor-matched HER2 CAR-T cells against tumor targets. Importantly, unlike CAR-T cells, HER2 CAR-NK cells do not elicit enhanced cytotoxicity or inflammatory cytokine production against non-malignant human lung epithelial cells with basal HER2 expression. Further, HER2 CAR-NK cells maintain high cytotoxic function in the presence of immunosuppressive factors enriched in solid tumors. These results show that CAR-NK cells may be a highly potent and safe source of immunotherapy in the context of solid tumors.
Project description:Solid tumors are refractory to cellular immunotherapies in part because they contain suppressive immune effectors such as myeloid-derived suppressor cells (MDSCs) that inhibit cytotoxic lymphocytes. Strategies to reverse the suppressive tumor microenvironment (TME) should also attract and activate immune effectors with antitumor activity. To address this need, we developed gene-modified natural killer (NK) cells bearing a chimeric receptor in which the activating receptor NKG2D is fused to the cytotoxic ζ-chain of the T-cell receptor (NKG2D.ζ). NKG2D.ζ-NK cells target MDSCs, which overexpress NKG2D ligands within the TME. We examined the ability of NKG2D.ζ-NK cells to eliminate MDSCs in a xenograft TME model and improve the antitumor function of tumor-directed chimeric antigen receptor (CAR)-modified T cells. We show that NKG2D.ζ-NK cells are cytotoxic against MDSCs, but spare NKG2D ligand-expressing normal tissues. NKG2D.ζ-NK cells, but not unmodified NK cells, secrete proinflammatory cytokines and chemokines in response to MDSCs at the tumor site and improve infiltration and antitumor activity of subsequently infused CAR-T cells, even in tumors for which an immunosuppressive TME is an impediment to treatment. Unlike endogenous NKG2D, NKG2D.ζ is not susceptible to TME-mediated downmodulation and thus maintains its function even within suppressive microenvironments. As clinical confirmation, NKG2D.ζ-NK cells generated from patients with neuroblastoma killed autologous intratumoral MDSCs capable of suppressing CAR-T function. A combination therapy for solid tumors that includes both NKG2D.ζ-NK cells and CAR-T cells may improve responses over therapies based on CAR-T cells alone.
Project description:Acute myeloid leukemia (AML) still constitutes a dreadful disease with limited therapeutic options. Chimeric antigen receptor (CAR)-modified T cells struggle to target AML partly due to a lack of true AML-exclusive antigens and heterogeneity of the disease. Natural killer (NK) cells possess a high intrinsic killing capacity against AML and might be well suited for the treatment of this disease. However, the generation of primary CAR-NK cells can be difficult and time consuming. Therefore, robust systems for the generation of high numbers of CAR-NK cells under GMP conditions are required. Here we report on the automated generation of high numbers of primary CD33-targeting CAR-NK cells using the CliniMACS Prodigy® platform. Automated-produced CD33-CAR-NK cells showed similar phenotype and cytotoxicity compared to small-scale-produced CD33-CAR-NK cells in vitro and were able to strongly reduce leukemic burden in an OCI-AML2 NSG-SGM3 xenograft mouse model in vivo following a cross-site shipment of the cell product. This technology might be well suited for the generation of primary CAR-modified NK cells for a broad range of targets and could facilitate clinical transition.
Project description:BackgroundThe NK-92/5.28.z cell line (also referred to as HER2.taNK) represents a stable, lentiviral-transduced clone of ErbB2 (HER2)-specific, second-generation CAR-expressing derivative of clinically applicable NK-92 cells. This study addresses manufacturing-related issues and aimed to develop a GMP-compliant protocol for the generation of NK-92/5.28.z therapeutic doses starting from a well-characterized GMP-compliant master cell bank.Materials and methodsCommercially available GMP-grade culture media and supplements (fresh frozen plasma, platelet lysate) were evaluated for their ability to support expansion of NK-92/5.28.z. Irradiation sensitivity and cytokine release were also investigated.ResultsNK-92/5.28.z cells can be grown to clinically applicable cell doses of 5 × 108 cells/L in a 5-day batch culture without loss of viability and potency. X-Vivo 10 containing recombinant transferrin supplemented with 5% FFP and 500 IU/mL IL-2 in VueLife 750-C1 bags showed the best results. Platelet lysate was less suited to support NK-92/5.28.z proliferation. Irradiation with 10 Gy completely abrogated NK-92/5.28.z proliferation and preserved viability and potency for at least 24 h. NK-92/5.28.z showed higher baseline cytokine release compared to NK-92, which was significantly increased upon encountering ErbB2(+) targets [GZMB (twofold), IFN-γ (fourfold), IL-8 (24-fold) and IL-10 (fivefold)]. IL-6 was not released by NK cells, but was observed in some stimulated targets. Irradiation resulted in upregulation of IL-8 and downregulation of sFasL, while other cytokines were not impacted.ConclusionOur concept suggests NK-92/5.28.z maintenance culture from which therapeutic doses up to 5 × 109 cells can be expanded in 10 L within 5 days. This established process is feasible to analyze NK-92/5.28.z in phase I/II trials.