Colorectal cancer (CRC), a major global health concern, necessitates innovative treatments. Chimeric antigen receptor (CAR) T cells have shown promises, yet they grapple with challenges. The spotlight pivots to the rising heroes: CAR natural killer (NK) cells, offering advantages such as higher safety profiles, cost-effectiveness, and efficacy against solid tumors. Nevertheless, the specific mechanisms underlying CAR NK cell trafficking and their interplay within the complex tumor microenvironment require further in-depth exploration. Herein, we provide insights into the design and engineering of CAR NK cells, antigen targets in CRC, and success in overcoming resistance mechanisms with an emphasis on the potential for clinical trials.
Colorectal Neoplasms/immunology* ; Humans ; Killer Cells, Natural/metabolism* ; Receptors, Chimeric Antigen/genetics* ; Immunotherapy, Adoptive/methods* ; Tumor Microenvironment/immunology* ; Animals

BACKGROUND: Several studies have demonstrated the occurrence of secondary tumors as a rare but significant complication of chimeric antigen receptor T (CAR-T) cell therapy, underscoring the need for a detailed investigation. Given the limited variety of secondary tumor types reported to date, a comprehensive characterization of the various secondary tumors arising after CAR-T therapy is essential to understand the associated risks and to define the role of the immune microenvironment in malignant transformation. This study aims to characterize the immune microenvironment of a newly identified secondary tumor post-CAR-T therapy, to clarify its pathogenesis and potential therapeutic targets. METHODS: In this study, the bone marrow (BM) samples were collected by aspiration from the primary and secondary tumors before and after CD19 CAR-T treatment. The CD45 + BM cells were enriched with human CD45 microbeads. The CD45 + cells were then sent for 10× genomics single-cell RNA sequencing (scRNA-seq) to identify cell populations. The Cell Ranger pipeline and CellChat were used for detailed analysis. RESULTS: In this study, a rare type of secondary chronic myelomonocytic leukemia (CMML) were reported in a patient with diffuse large B-cell lymphoma (DLBCL) who had previously received CD19 CAR-T therapy. The scRNA-seq analysis revealed increased inflammatory cytokines, chemokines, and an immunosuppressive state of monocytes/macrophages, which may impair cytotoxic activity in both T and natural killer (NK) cells in secondary CMML before treatment. In contrast, their cytotoxicity was restored in secondary CMML after treatment. CONCLUSIONS This finding delineates a previously unrecognized type of secondary tumor, CMML, after CAR-T therapy and provide a framework for defining the immune microenvironment of secondary tumor occurrence after CAR-T therapy. In addition, the results provide a rationale for targeting macrophages to improve treatment strategies for CMML treatment.
Humans ; Lymphoma, Large B-Cell, Diffuse/therapy* ; Tumor Microenvironment/genetics* ; Antigens, CD19/metabolism* ; Leukemia, Myelomonocytic, Chronic/genetics* ; Immunotherapy, Adoptive/adverse effects* ; Male ; Single-Cell Analysis/methods* ; Female ; Sequence Analysis, RNA/methods* ; Receptors, Chimeric Antigen ; Middle Aged

Tumor immunotherapy has revolutionized the treatment prospects for various malignant tumors. Immune checkpoint inhibitors (ICIs) and chimeric antigen receptor T-cell therapy (CAR-T) , as representative of tumor immunotherapy, have achieved tremendous success in clinical practice and have become the first-line clinical treatment options for certain tumors. This article summarizes the progress and challenges of immune checkpoint inhibitors and CAR-T therapy in tumor treatment, and discusses the future direction of tumor therapeutic vaccines development. Identifying novel therapeutic targets within the realm of tumor immunology, engineering innovative drug delivery systems, and employing combinatorial therapeutic strategies are poised to enhance therapeutic efficacy and patient outcomes in oncology, thereby extending benefits to a broader patient population.
Humans ; Neoplasms/immunology* ; Immune Checkpoint Inhibitors/therapeutic use* ; Receptors, Chimeric Antigen/genetics* ; Immunotherapy/methods* ; Immunotherapy, Adoptive/methods* ; Animals ; Cancer Vaccines/therapeutic use*

Chimeric antigen receptor T (CAR-T) lymphocytes are at the forefront of adoptive immunotherapy research, and this technology has significantly advanced the prospects of tumor immunotherapy. CAR-T therapy has demonstrated remarkable efficacy in haematological tumours of lymphoid origin and provided therapeutic possibility for solid tumours. Currently, CAR-T cell preparation predominantly involves transfection of T cells with viral vectors. However, the production of viral vectors is time-consuming, expensive, and the vectors have low loading capacity, along with insertion instability. Consequently, there is a pressing need to develop more convenient and precise non-viral gene delivery methods. This paper reviews the most promising non-viral gene delivery technologies, including CRISPR/Cas9 gene editing, transposon systems such as Sleeping Beauty (SB) and PiggyBac (PB), and mRNA, and anticipates the future development of non-viral vector-based CAR-T therapies.
Humans ; Immunotherapy, Adoptive/methods* ; Receptors, Chimeric Antigen/immunology* ; Animals ; Gene Transfer Techniques ; Genetic Vectors/genetics* ; Gene Editing ; CRISPR-Cas Systems/genetics* ; DNA Transposable Elements/genetics* ; T-Lymphocytes/immunology* ; Neoplasms/immunology*

Objective To investigate the effect of ATP synthase inhibitory factor 1 (ATPIF1) on the antitumor activity of chimeric antigen receptor (CAR)-NK92 cells. Methods HER2-targeted CAR-NK92 cells with ATPIF1 overexpression or knockdown were constructed. CAR-positive expression rate was detected by flow cytometry. Cell proliferation capacity was measured using CCK-8 assay. Glycolytic capacity was analyzed by Seahorse metabolic analyzer. Mitochondrial membrane potential levels were detected using JC-1 probe. Target cell lysis rate was evaluated by firefly luciferase reporter assay. Expression levels of CD107a, natural-killer group 2 member D (NKG2D), granzyme B (GzmB), perforin, and interleukin 2 (IL-2) were detected via flow cytometry. Quantitative real-time PCR was used to measure the expression of interferon-induced protein with tetratricopeptide repeats 1 (IFIT1), tumor necrosis factor α (TNF-α), ATPIF1, and hexokinase 1 (HK1). The impact of glycolytic inhibition by 2-Deoxy-D-glucose (2-DG) on CAR-NK92 antitumor capacity was examined. Results Successfully generated HER2-targeting control CAR-NK92 cells, as well as ATPIF1-overexpressing and ATPIF1 knockdown CAR-NK92 cells. The ATPIF1-overexpressing CAR-NK92 cells showed significantly enhanced target cell lysis rate, elevated expression levels of NKG2D and CD107a, increased secretion capacities of Granzyme B (GzmB) and IL-2, and upregulated mRNA expression levels of IFIT1 and TNF-α, while ATPIF1-knockdown cells exhibited opposite effects. ATPIF1 overexpression induced metabolic reprogramming in CAR-NK92 cells, manifested by significantly decreased mitochondrial membrane potential (δpsim), markedly upregulated HK1 mRNA expression, and enhanced basal glycolysis and glycolytic capacity. After glycolysis inhibition with 2-DG (5 μmol/L), both ATPIF1-overexpressing and knockdown CAR-NK92 cells showed no significant differences in NKG2D and CD107a expression levels compared to control cells. Conclusion ATPIF1 regulates the antitumor activity of CAR-NK92 cells through modulating glycolytic metabolism. Overexpression of ATPIF1 can enhance the antitumor efficacy of CAR-NK92 cells.
Humans ; Glycolysis ; Killer Cells, Natural/metabolism* ; Receptors, Chimeric Antigen/immunology* ; Granzymes/genetics* ; Hexokinase/metabolism* ; Cell Line, Tumor ; Interleukin-2/genetics* ; Cell Proliferation ; NK Cell Lectin-Like Receptor Subfamily K/genetics* ; Membrane Potential, Mitochondrial

Cancer immunotherapy including immune checkpoint inhibitors and adoptive cell therapy has gained revolutionary success in the treatment of hematologic tumors; however, it only gains limited success in solid tumors. For example, chimeric antigen receptor T (CAR-T) cell therapy has shown significant effects and potential for curing patients with B-cell malignancies. In contrast, it remains a challenge for CAR-T cell therapy to gain similar success in solid tumors. The anti-tumor effect of endogenous or adoptively transferred tumor-specific T cells depends largely on their differentiation status. T cells at early differentiation stage show better anti-tumor therapeutic effects than fully differentiated effector T cells. In cancer patients, the persistence of tumor-specific T cells with the stem cell memory or precursor phenotype is significantly associated with improved therapeutic outcomes; therefore, adoptively transfered CAR-T cells with stem cell memory and/or central memory is expected to gain better anti-tumor effects. Herein we focused on the in vitro optimized culture and expansion system to obtain CAR-T cells with stem cell memory or central memory phenotype for the review.
Humans ; Immunotherapy, Adoptive/methods* ; Receptors, Chimeric Antigen/genetics* ; Neoplasms/immunology* ; Immunologic Memory ; T-Lymphocytes/immunology* ; Memory T Cells/immunology* ; Animals ; Stem Cells/cytology* ; Cell Differentiation

Humans ; Receptors, Chimeric Antigen/therapeutic use* ; DNA-Binding Proteins/genetics* ; Precursor B-Cell Lymphoblastic Leukemia-Lymphoma ; Proto-Oncogene Proteins c-bcl-2/genetics* ; Cell- and Tissue-Based Therapy ; Oncogene Proteins, Fusion/genetics* ; Translocation, Genetic

Objective To investigate a convenient and quantitative solution to activation levels and functional characterization of CAR-T cells by inserting T cell activity-responsive promoter (TARP) nanoluciferase reporter gene system into a lentiviral plasmid containing the gene encoding the chimeric antigen receptor (CAR). Methods The recombinant plasmid was constructed by using whole gene synthesis and molecular cloning techniques. The lentivirus was packaged and was infected with human primary T lymphocytes. Flow cytometry was used to detected the positive rate of lentivirus-infected T cells. The functional characterization of CAR-T cells was identified by luciferase reporter gene system, Western blot, flow cytometry, and small animal live imaging techniques. Results The results of enzyme digestion identification and the plasmid sequencing showed that the recombinant plasmids were constructed, and flow cytometry displayed the normal preparation of CAR-T cells. This system could dynamically respond to the activation of CAR-T cells by luciferase reporter gene system. The functional assay in vitro confirmed that the system could reflect the exhaustion of CAR-T cells, and the small animal live imaging results demonstrated that the system can be used as a tracer of CAR-T cells in mice. Conclusion TARP nanoluciferase reporter gene system provides a more convenient, sensitive and quantitative method for evaluating CAR-T cells activation level, exhaustion phenotype and tracing.
Humans ; Animals ; Mice ; T-Lymphocytes ; Cell Line, Tumor ; Receptors, Chimeric Antigen/genetics* ; Promoter Regions, Genetic ; Immunotherapy, Adoptive/methods*

Objective This study aims to construct and identify the chimeric antigen receptor NK92 (CAR-NK92) cells targeting NKG2D ligand (NKG2DL) (secreting IL-15Ra-IL-15) and verify the killing activity of NKG2D CAR-NK92 cells against multiple myeloma cells. Methods The extracellular segment of NKG2D was employed to connect 4-1BB and CD3Z, as well as IL-15Ra-IL-15 sequence to obtain a CAR expression framework. The lentivirus was packaged and transduced into NK92 cells to obtain NKG2D CAR-NK92 cells. The proliferation of NKG2D CAR-NK92 cells was detected by CCK-8 assay, IL-15Ra secretion was detected by ELISA and killing efficiency was detected by lactate dehydrogenase (LDH) assay. The molecular markers of NKp30, NKp44, NKp46, the ratio of apoptotic cell population, CD107a, and the secretion level of granzyme B and perforin were detected using flow cytometry. In addition, the cytotoxic mechanism of NKG2D CAR-NK92 cells on the tumor was verified by measuring the degranulation ability. Moreover, after NKG2D antibody inhibited effector cells and histamine inhibited tumor cells, LDH assay was utilized to detect the effect on cell-killing efficiency. Finally, the multiple myeloma tumor xenograft model was constructed to verify its anti-tumor activity in vivo. Results Lentiviral transduction significantly increased NKG2D expression in NK92 cells. Compared with NK92 cells, the proliferation ability of NKG2D CAR-NK92 cells was weaker. The early apoptotic cell population of NKG2D CAR-NK92 cells was less, and NKG2D CAR-NK92 cells had stronger cytotoxicity to multiple myeloma cells. Additionally, IL-15Ra secretion could be detected in its culture supernatant. NKp44 protein expression in NKG2D CAR-NK92 cells was clearly increased, demonstrating an enhanced activation level. Inhibition test revealed that the cytotoxicity of CAR-NK92 cells to MHC-I chain-related protein A (MICA) and MICB-positive tumor cells was more dependent on the interaction between NKG2D CAR and NKG2DL. After stimulating NKG2D CAR-NK92 cells with tumor cells, granzyme B and perforin expression increased, and NK cells obviously upregulated CD107α. Furthermore, multiple myeloma tumor xenograft model revealed that the tumors of mice treated with NKG2D CAR-NK92 cells were significantly reduced, and the cell therapy did not sensibly affect the weight of the mice. Conclusion A type of CAR-NK92 cell targeting NKG2DL (secreting IL-15Ra-IL-15) is successfully constructed, indicating the effective killing of multiple myeloid cells.
Humans ; Mice ; Animals ; Receptors, Chimeric Antigen/genetics* ; Interleukin-15 ; NK Cell Lectin-Like Receptor Subfamily K/metabolism* ; Granzymes ; Cell Line, Tumor ; Multiple Myeloma/therapy* ; Perforin

Adoptive therapeutic immune cells, such as chimeric antigen receptor (CAR)-T cells and natural killer cells, have established a new generation of precision medicine based on which dramatic breakthroughs have been achieved in intractable lymphoma treatments. Currently, well-explored approaches focus on autologous cells due to their low immunogenicity, but they are highly restricted by the high costs, time consumption of processing, and the insufficiency of primary cells in some patients. Induced pluripotent stem cells (iPSCs) are cell sources that can theoretically produce indefinite well-differentiated immune cells. Based on the above facts, it may be reasonable to combine the iPSC technology and the CAR design to produce a series of highly controllable and economical "live" drugs. Manufacturing hypoimmunogenic iPSCs by inactivation or over-expression at the genetic level and then arming the derived cells with CAR have emerged as a form of "off-the-shelf" strategy to eliminate tumor cells efficiently and safely in a broader range of patients. This review describes the reasonability, feasibility, superiority, and drawbacks of such approaches, summarizes the current practices and relevant research progress, and provides insights into the possible new paths for personalized cell-based therapies.
Humans ; Receptors, Chimeric Antigen/genetics* ; Induced Pluripotent Stem Cells ; Killer Cells, Natural ; Cell- and Tissue-Based Therapy ; T-Lymphocytes ; Immunotherapy, Adoptive ; Neoplasms/genetics*