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

Objective To generate and characterize natural killer cell (NK cell)-conditional Cd226 gene knockout mice using Cre-loxP technology, and to explore the role of CD226 on NK cells in alleviating intestinal inflammation in a murine model of ulcerative colitis (UC). Methods NK cell-conditional Cd226 gene knockout mice were generated by crossing loxP-flanked Cd226 mice with Ncr1-Cre mice via the Cre-loxP system. Polymerase chain reaction (PCR) and agarose gel electrophoresis were used for genotyping. A UC model was established by dextran sulfate sodium (DSS) induction. Flow cytometry was performed to analyze CD226 expression levels on NK cells and the infiltration of related immune cells in colon tissues. Hematoxylin-eosin (HE) staining was performed to assess the degree of colonic inflammation. Results DNA gel electrophoresis and flow cytometry confirmed the successful generation of NK cell-specific Cd226 knockout mice. After conditional knockout of Cd226 in NK cells, inflammation in the UC mouse model was alleviated. Flow cytometry results showed a reduced proportion of NK cells in peripheral blood and the colon lamina propria, while HE staining demonstrated attenuated inflammatory responses. Conclusion Specific knockout of Cd226 in NK cells mitigates intestinal inflammation in UC mice by reducing NK cell numbers and inhibiting their pro-inflammatory functions.
Animals ; Colitis, Ulcerative/pathology* ; Killer Cells, Natural/metabolism* ; Mice, Knockout ; T Lineage-Specific Activation Antigen 1 ; Antigens, Differentiation, T-Lymphocyte/genetics* ; Mice ; Disease Models, Animal ; Mice, Inbred C57BL ; Male

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

OBJECTIVES: To evaluate the clinical value of CD4⁺ cell percentage (CD4⁺%) and NK cell percentage (NK%) in predicting treatment outcomes in children with aplastic anemia (AA), providing a reference for precise diagnosis and treatment. METHODS: This retrospective study analyzed the clinical data of AA children treated with cyclosporine A at the First Affiliated Hospital of Xinjiang Medical University from January 2019 to April 2024. The study involved 48 AA children as the observation group and 50 children undergoing medical check-ups during the same period as the control group. Lymphocyte subset data were collected from both groups to analyze differences and their relationship with treatment efficacy. Based on hematological responses, the observation group was divided into an effective group of 18 patients (HR group, including complete and partial remission) and an ineffective group of 30 patients (NHR group, including non-remission). RESULTS: Univariate analysis showed that NK% in the observation group was significantly lower than that in the control group (P<0.05). The observation group was followed up for 3 months. The HR group had a lower CD4⁺% than the NHR group (P=0.018) and a higher NK% than the NHR group (P=0.029). Multivariate logistic regression analysis indicated that a high CD4⁺% was a risk factor for poor treatment efficacy (OR=1.062), whereas a high NK% was a protective factor (OR=0.820). The area under the curve for the prediction of HR in pediatric AA by combining CD4⁺% and NK% was 0.812. CONCLUSIONS A higher CD4⁺% at diagnosis is a predictor of poor treatment response, whereas a higher NK% is associated with better outcomes.
Humans ; Anemia, Aplastic/blood* ; Male ; Female ; Killer Cells, Natural ; Child ; Retrospective Studies ; Child, Preschool ; Prognosis ; Adolescent ; CD4-Positive T-Lymphocytes ; Infant

OBJECTIVE: To explore the effect and mechanism of DNA methyltransferase 1 (DNMT1) knockout on the inhibition of acute myeloid leukemia (AML) by natural killer (NK) cells. METHODS: The peripheral blood NK cells of AML patients and controls were collected, and the mRNA and protein level of DNMT1 were measured by PCR and Western blot, respectively. The DNMT1 knockout mice were constructed to obtain NK^DNMT1-/- cells. The NK cells were stimulated with interleukin (IL)-12, IL-15, and IL-18 to construct memory NK cells, and then the interferon-γ (IFN-γ) levels were measured by ELISA. After co-culturing with memory NK cells and HL60 cells, the killing effect of NK^DNMT1-/- cells on HL60 cells was detected by LDH assay. Then, the HL60 cell apoptosis and NK cell NKG2D level were measured by flow cytometry. The perforin and granzyme B protein levels of NK cells were measured by Western blot. The AML model mice were constructed by injecting HL60 cells into the tail vein, meanwhile, memory NK cells were also injected, and then the mouse weights, CD33 positive rates, and survival time were detected. RESULTS: The mRNA and protein levels of DNMT1 in NK cells of AML patients were significantly higher than those in the control group (both P < 0.01), while the IFN-γ level induced by interleukin was significantly lower than that in the control group (P < 0.05). Compared with NK^DNMT1+/+ cells, the ability of NK^DNMT1-/- cells to secrete IFN-γ after interleukin stimulation was significantly increased (P < 0.05). The killing and apoptosis-inducing effects of NK^DNMT1-/- cells on HL60 cells were significantly stronger than those of NK^DNMT1+/+ cells (both P < 0.05). The NKG2D level and expression of perforin and granzyme B of NK^DNMT1-/- cells were significantly increased compared with NK^DNMT1+/+ cells (all P < 0.05). Compared with AML mice injected with NK^DNMT1+/+ cells, AML mice injected with NK^DNMT1-/- cells showed significantly increased body weight, decreased CD33 positive rate, and prolonged survival time (all P < 0.05). CONCLUSION Knocking out DNMT1 can enhance the inhibitory effect of NK cells on AML, which may be related to enhancing NK cell memory function.
Killer Cells, Natural/metabolism* ; Animals ; Leukemia, Myeloid, Acute ; Humans ; DNA (Cytosine-5-)-Methyltransferase 1 ; Mice ; Mice, Knockout ; HL-60 Cells ; Apoptosis ; Interferon-gamma/metabolism* ; Granzymes/metabolism* ; Perforin/metabolism* ; NK Cell Lectin-Like Receptor Subfamily K/metabolism*

OBJECTIVE: To investigate the correlation between the types and quantities of immune cells in the graft and early immune reconstitution after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and their influence on clinical prognosis. METHODS: The clinical data of 83 patients with hematological diseases who received allo-HSCT in Shanxi Bethune Hospital from September 2020 to June 2023 were retrospectively analyzed. The number of mononuclear cells (MNC), CD34⁺ cells and lymphocyte subsets (including CD3⁺T, CD3⁺CD4⁺T(Th), CD3⁺CD8⁺T(Ts), NK cells and B cells) infused into the recipients was counted, and the peripheral blood lymphocytes were detected before conditioning and on days 14, 30, 60 and 100 post-HSCT. RESULTS: Multivariate analysis showed that the number of MNC in the graft affected the recovery of CD4⁺T lymphocytes after HSCT, and the number of CD4⁺T lymphocytes in the graft affected the recovery of NK cells and B cells after HSCT. The patient age, donor sex, stem cell source, degree of HLA matching, use of ATG before HSCT, the occurrence of acute graft-versus-host disease (aGVHD) after HSCT, and viral infection all affect the early cellular immune reconstitution post-HSCT. The number of infused cells had no significant impact on the median engraftment time for neutrophils and platelets after HSCT. Patients with lower numbers of CD3⁺T, CD4⁺T and B cells in the graft were more prone to viral infection after HSCT. However, the cells in the graft had no significant effect on disease recurrence or mortality. CONCLUSION The recovery rate of lymphocyte count after allo-HSCT varies. The numbers of MNC and CD4⁺T cells in the graft may be related to the cellular immune reconstitution after HSCT, while the numbers of CD34⁺,CD3⁺T,CD8⁺T,NK and B cells have no significant effect on the cellular immune reconstruction. The numbers of CD3⁺T,CD4⁺T and B cells in the graft were negatively correlated with viral infection after HSCT, but the cellular components of the graft have no obvious influence on hematopoietic reconstitution, disease recurrence, death, recurrence-free survival(RFS) and overall survival(OS) after HSCT.
Humans ; Hematopoietic Stem Cell Transplantation ; Immune Reconstitution ; Transplantation, Homologous ; Retrospective Studies ; Graft vs Host Disease/immunology* ; Male ; Female ; Killer Cells, Natural/immunology* ; Adult ; Middle Aged ; B-Lymphocytes/immunology* ; Prognosis ; Lymphocyte Subsets/immunology* ; Adolescent

OBJECTIVE: To analyze the Epstein-Barr virus (EBV) load in different lymphocyte subsets, as well as clinical characteristics and outcomes in patients with hematologic malignancies experiencing EBV reactivation. METHODS: Peripheral blood samples from patients were collected. B, T, and NK cells were isolated sorting with magnetic beads by flow cytometry. The EBV load in each subset was quantitated by real-time quantitative polymerase chain reaction (RT-qPCR). Clinical data were colleted from electronic medical records. Survival status was followed up through outpatient visits and telephone calls. Statistical analyses were performed using SPSS 25.0. RESULTS: A total of 39 patients with hematologic malignancies were included, among whom 35 patients had undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT). The median time to EBV reactivation was 4.8 months (range: 1.7-57.1 months) after allo-HSCT. EBV was detected in B, T, and NK cells in 20 patients, in B and T cells in 11 patients, and only in B cells in 4 patients. In the 35 patients, the median EBV load in B cells was 2.19×10⁴ copies/ml, significantly higher than that in T cells (4.00×10³ copies/ml, P <0.01) and NK cells (2.85×10² copies/ml, P <0.01). Rituximab (RTX) was administered for 32 patients, resulting in EBV negativity in 32 patients with a median time of 8 days (range: 2-39 days). Post-treatment analysis of 13 patients showed EBV were all negative in B, T, and NK cells. In the four non-transplant patients, the median time to EBV reactivation was 35 days (range: 1-328 days) after diagnosis of the primary disease. EBV was detected in one or two subsets of B, T, or NK cells, but not simultaneously in all three subsets. These patients received a combination chemotherapy targeting at the primary disease, with 3 patients achieving EBV negativity, and the median time to be negative was 40 days (range: 13-75 days). CONCLUSION In hematologic malignancy patients after allo-HSCT, EBV reactivation commonly involves B, T, and NK cells, with a significantly higher viral load in B cells compared to T and NK cells. Rituximab is effective for EBV clearance. In non-transplant patients, EBV reactivation is restricted to one or two lymphocyte subsets, and clearance is slower, highlighting the need for prompt anti-tumor therapy.
Humans ; Hematologic Neoplasms/virology* ; Herpesvirus 4, Human/physiology* ; Epstein-Barr Virus Infections ; Hematopoietic Stem Cell Transplantation ; Virus Activation ; Lymphocyte Subsets/virology* ; Flow Cytometry ; Killer Cells, Natural/virology* ; Male ; Female ; B-Lymphocytes/virology* ; Viral Load ; Adult ; T-Lymphocytes/virology* ; Middle Aged

Otitis media is an infection of the middle ear mainly caused by bacteria, and current treatments rely heavily on antibiotics. However, the emergence of antibiotic-resistant bacterial strains seriously affects their efficacy. In our study, we found that extracellular vesicles (EVs) derived from human natural killer cells (NKs) inhibit the proliferation of both standard and levofloxacin (LVX)-resistant strains of Staphylococcus aureus in a dose-dependent manner. Moreover, compared to LVX, EVs were more effective at reducing effusion and rescuing hearing thresholds in animal models. For LVX-sensitive strains, EVs were significantly more effective in terms of curative time but not curative rate. For LVX-resistant strains, EVs were significantly more effective in terms of both curative rate and curative time when applied alone or applied jointly with LVX. In summary, we found that NK EVs are highly effective in treating otitis media, providing an alternative approach for treating this common disease.
Killer Cells, Natural/metabolism* ; Exosomes/metabolism* ; Animals ; Humans ; Otitis Media/therapy* ; Staphylococcus aureus/drug effects* ; Disease Models, Animal ; Anti-Bacterial Agents/pharmacology* ; Levofloxacin/pharmacology*

Hepatocellular carcinoma (HCC) is well characterized as a heterogeneous disease. Its late-stage diagnosis and chemotherapy resistance make it one of the refractory tumors in China. Natural killer (NK) cells play a significant role in immune surveillance. However, NK cells become dysfunctional in the progression of HCC, leading to tumor immune escape. This article reviews the recent progress on different strategies of NK cell-based immunotherapy in treating HCC, including direct adoptive NK cell transfer, gene engineering in NK cell, NK cell receptor targeting, immunosuppressive microenvironment modification, and tumor toxicity enhancement by cytokines or traditional Chinese medicine. These NK cell-based strategies have shown promising therapeutic potential.
Humans ; Carcinoma, Hepatocellular/therapy* ; Liver Neoplasms/therapy* ; Immunotherapy ; Killer Cells, Natural ; Receptors, Natural Killer Cell ; Tumor Microenvironment

Objective To investigate the effects of evodiamine (EVO) on Natural Killer (NK) cell-mediated killing in small cell lung cancer (SCLC) cells via affecting baculoviral inhibitor of apoptosis repeat containing 5 (BIRC5). Methods H446 cells and NK-92 cells were treated with EVO at different concentrations, and cell proliferation was detected using the MTT (3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay, while cell invasion was assessed using the Transwell^TM assay. NK-92 cells and H446 cells were co-cultured at different effector-to-target ratios to detect the cytotoxicity of NK cells against H446 cells and the level of degranulation in NK-92 cells. Network pharmacology was employed to analyze the potential targets of EVO in the treatment of SCLC, and further validation was conducted to elucidate the mechanism of EVO's action in SCLC. An xenograft tumor model was used to evaluate the effect of EVO on tumor growth. Results Compared with the control group, EVO treatment dose-dependently inhibited the proliferation and invasion of H446 cells, while enhancing the cytotoxicity of NK-92 cells against H446 cells and the level of NK-92 cell degranulation. Network pharmacological analysis revealed that BIRC5 is a core target of EVO in the treatment of SCLC, and EVO suppressed the expression of BIRC5 protein without affecting BIRC5 mRNA expression. In vivo studies demonstrated that EVO inhibited tumor growth in a dose-dependent manner. Conclusion EVO promotes the degradation of BIRC5, thus enhancing the killing effects of NK cells on SCLC cells.
Humans ; Killer Cells, Natural/metabolism* ; Small Cell Lung Carcinoma/genetics* ; Animals ; Lung Neoplasms/genetics* ; Quinazolines/pharmacology* ; Cell Line, Tumor ; Survivin/genetics* ; Cell Proliferation/drug effects* ; Mice ; Mice, Nude ; Mice, Inbred BALB C ; Xenograft Model Antitumor Assays