• BMB Reports
• /
• 제54권1호
• /
• pp.44-58
• /
• 2021

Natural killer (NK) cells, key antitumor effectors of the innate immune system, are endowed with the unique ability to spontaneously eliminate cells undergoing a neoplastic transformation. Given their broad reactivity against diverse types of cancer and close association with cancer prognosis, NK cells have gained considerable attention as a promising therapeutic target for cancer immunotherapy. NK cell-based therapies have demonstrated favorable clinical efficacies in several hematological malignancies but limited success in solid tumors, thus highlighting the need to develop new therapeutic strategies to restore and optimize anti-tumor activity while preventing tumor immune escape. The current therapeutic modalities yielding encouraging results in clinical trials include the blockade of immune checkpoint receptors to overcome the immune-evasion mechanism used by tumors and the incorporation of tumor-directed chimeric antigen receptors to enhance NK cell anti-tumor specificity and activity. These observations, together with recent advances in the understanding of NK cell activation within the tumor microenvironment, will facilitate the optimal design of NK cell-based therapy against a broad range of cancers and, more desirably, refractory cancers.

• Molecules and Cells
• /
• 제47권3호
• /
• pp.100007.1-100007.11
• /
• 2024

Recent evidence establishes a pivotal role for obesity-induced inflammation in precipitating insulin resistance and type-2 diabetes. Central to this process is the proinflammatory M1 adipose-tissue macrophages (ATMs) in epididymal white adipose tissue (eWAT). Notably, natural killer (NK) cells are a crucial regulator of ATMs since their cytokines induce ATM recruitment and M1 polarization. The importance of NK cells is shown by the strong increase in NK-cell numbers in eWAT, and by studies showing that removing and expanding NK cells respectively improve and worsen obesity-induced insulin resistance. It has been suggested that NK cells are activated by unknown ligands on obesity-stressed adipocytes that bind to NKp46 (encoded by Ncr1), which is an activating NK-cell receptor. This was supported by a study showing that NKp46-knockout mice have improved obesity-induced inflammation/insulin resistance. We therefore planned to use the NKp46-knockout mice to further elucidate the molecular mechanism by which NKp46 mediates eWAT NK-cell activation in obesity. We confirmed that obesity increased eWAT NKp46⁺ NK-cell numbers and NKp46 expression in wild-type mice and that NKp46-knockout ablated these responses. Unexpectedly, however, NKp46-knockout mice demonstrated insulin resistance similar to wild-type mice, as shown by fasting blood glucose/insulin levels and glucose/insulin tolerance tests. Obesityinduced increases in eWAT ATM numbers and proinflammatory gene expression were also similar. Thus, contrary to previously published results, NKp46 does not regulate obesity-induced insulin resistance. It is therefore unclear whether NKp46 participates in the development of obesity-induced inflammation and insulin resistance. This should be considered when elucidating the obesity-mediated molecular mechanisms that activate NK cells.

• Clinical and Experimental Reproductive Medicine
• /
• 제32권3호
• /
• pp.217-222
• /
• 2005

Objectives: We aimed to investigate the clinical effect of low-dose intravenous immunoglobulin treatment in unexplained recurrent spontaneous aborters (RSA) with elevated peripheral CD56+ natural killer (NK) cell levels and to determine the pre-conceptional NK cell percentage predictive of subsequent successful pregnancy outcome. Materials and Methods: Sixty four cases of unexplained recurrent miscarriage with elevated peripheral NK cells (>15%) were received low dose IVIg infusion at the dosage of 400 mg/Kg/month after confirmation of gestational sac and continued until 20 weeks. The patients were divided into two groups according to the pregnancy outcome: Group I was success of treatment defined as live birth at or after 25 gestational weeks and Group II was failure of treatment. The preconceptional levels of the peripheral blood NK cells were compared between two groups. Results: Fifty-three pregnancies resulted in live births after 25 weeks and 11 resulted in abortion (Overall success rate of IVIG treatment was 82.8%). Preconceptional CD56+ NK cell percentage in group II ($27.4{\pm}1.9%$) was higher than those in group I ($22.3{\pm}0.8%$). By using ROC curve, optimal discrimination between success and failure of treatment was achieved with ${\leq}27%$ of preconceptional NK cell percentage. Conclusion: In RSA patients with elevated NK cells, we suggest that preconceptional peripheral blood CD56+ NK cell level could be a useful marker for predicting successful treatment outcome of low-dose IVIg infusion.

• Journal of Microbiology and Biotechnology
• /
• 제34권4호
• /
• pp.920-929
• /
• 2024

As a pivotal defensive line against multitudinous malignant tumors, natural killer (NK) cells exist in the tumor microenvironment (TME). RAD18 E3 Ubiquitin Protein Ligase (RAD18) has been reported to foster the malignant progression of multiple cancers, but its effect on NK function has not been mined. Here, the study was designed to mine the mechanism by which RAD18 regulates the killing effect of NK cells on colorectal cancer (CRC) cells. Expression of E2F Transcription Factor 7 (E2F7) and RAD18 in CRC tissues, their correlation, binding sites, and RAD18 enrichment pathway were analyzed by bioinformatics. Expression of E2F7 and RAD18 in cells was assayed by qRT-PCR and western blot. Dual-luciferase assay and chromatin immunoprecipitation (ChIP) assay verified the regulatory relationship between E2F7 and RAD18. CCK-8 assay was utilized to assay cell viability, colony formation assay to detect cell proliferation, lactate dehydrogenase (LDH) test to assay NK cell cytotoxicity, ELISA to assay levels of granulocyte-macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), and immunofluorescence to detect expression of toxic molecules perforin and granzyme B. High expression of RAD18 and E2F7 was found in CRC tissues and cells. Silencing RAD18 could hamper the proliferation of CRC cells, foster viability and cytotoxicity of NK cells, and increase the secretion of GM-CSF, TNF-α, IFN-γ as well as the expression of perforin and granzyme B. Additionally, ChIP and dual-luciferase reporter assay ascertained the binding relationship between RAD18 promoter region and E2F7. E2F7 could activate the transcription of RAD18, and silencing RAD18 reversed the inhibitory effect of E2F7 overexpression on NK cell killing. This work clarified the inhibitory effect of the E2F7/RAD18 axis on NK cell killing in CRC, and proffered a new direction for immunotherapy of CRC in targeted immune microenvironment.

• Journal of Korean Neurosurgical Society
• /
• 제66권4호
• /
• pp.356-381
• /
• 2023

Although immunotherapy has been broadly successful in the treatment of hematologic malignancies and a subset of solid tumors, its clinical outcomes for glioblastoma are still inadequate. The results could be due to neuroanatomical structures such as the blood-brain-barrier, antigenic heterogeneity, and the highly immunosuppressive microenvironment of glioblastomas. The antitumor efficacy of endogenously activated effector cells induced by peptide or dendritic cell vaccines in particular has been insufficient to control tumors. Effector cells, such as T cells and natural killer (NK) cells can be expanded rapidly ex vivo and transferred to patients. The identification of neoantigens derived from tumor-specific mutations is expanding the list of tumor-specific antigens for glioblastoma. Moreover, recent advances in gene-editing technologies enable the effector cells to not only have multiple biological functionalities, such as cytokine production, multiple antigen recognition, and increased cell trafficking, but also relieve the immunosuppressive nature of the glioblastoma microenvironment by blocking immune inhibitory molecules, which together improve their cytotoxicity, persistence, and safety. Allogeneic chimeric antigen receptor (CAR) T cells edited to reduce graft-versus-host disease and allorejection, or induced pluripotent stem cell-derived NK cells expressing CARs that use NK-specific signaling domain can be a good candidate for off-the-shelf products of glioblastoma immunotherapy. We here discuss current progress and future directions for T cell and NK cell therapy in glioblastoma.

• 대한의생명과학회지
• /
• 제29권3호
• /
• pp.178-183
• /
• 2023

Natural killer (NK) cells are innate cytotoxic lymphoid cells that actively prevent neoplastic development, growth, and metastatic dissemination in a process called cancer immunosurveillance. Regulation of the cytotoxic activity of NK cells relies on integrated interactions between inhibitory receptors and numerous activating receptors that act in tandem to eliminate tumor cells efficiently. Conventional chemotherapy is designed to produce an anti-proliferative or cytotoxic effect on early tumor cell division. Therapies designed to kill cancer cells and simultaneously maintain host anti-tumor immunity are attractive strategies for controlling tumor growth. Depending on the drug and dose used, several chemotherapeutic agents cause DNA damage and cancer cell death through apoptosis, immunogenic cell death, or other forms of non-killing (i.e., mitotic catastrophe, senescence, autophagy). Among stress-induced immunostimulatory proteins, changes in the expression levels of NK cell activating and inhibitory ligands and tumor cell death receptors play an important role in the detection and elimination by innate immune effectors including NK cells. Therefore, we will address how these cytotoxic lymphocytes sense and respond to high and low concentrations of drug-induced stress to the drug cisplatin, among the various types of drugs that contribute to their anticancer activity.

• 정신신체의학
• /
• 제3권1호
• /
• pp.3-10
• /
• 1995

A comparison was made between the effect of subjective stress and that of objective stress on immune function in male medical college students. Interaction between perceived stress, psychopathology and natural killer-cell(NK) activity was assessed during an exam period, non-exam period, and vacation. No significant difference was found in NK activity among these three periods, but scores of perceived stress related to unusual happenings during an exam period and related to interpersonal relationship during vacation were found to have significantly positive correlation with NK activity, respectively. In psychopathology, only scores of anxiety during an exam period had significantly positive correlation with NK activity. These results suggest that immune function is more likely to be affected by subjective stress than objective stress and that subjective stress such as some perceived stress and subclinical level of anxiety may positively affect immune function.

• 약학회지
• /
• 제44권2호
• /
• pp.169-174
• /
• 2000

Pedunculagin is an ellagitannin purified from Alnus hirsuta var. microphylla. Betulaceae. The effects of pedunculagin on immune system have been characterized to induce enhancement of NK (natural killer) cell cytotoxicities against tumor cells. Here, we report the evaluation of the effects of pedunculagin on the growth of murine Bl6-F10 melanoma in vivo. After the intradermal inoculation of Bl6-F10 melanoma, Bl6-F10 tumors grew progressively in immunocompetent syngenic C57BL/6 mice. The mice treated with pedunculagin(10 mg/kg, every 48 hrs) resulted in a significant improvement in survival. Inhibitory effects of pedunculagin on lung metastasis in C57BL/6 mice were also detected. Summarizing treatment with pedunculagin has a significant antitumor effect upon Bl6-F10 murine melanoma.

• Journal of Microbiology and Biotechnology
• /
• 제32권5호
• /
• pp.612-620
• /
• 2022

Recent studies have revealed that probiotics and their metabolites are present under various conditions; however, the role of probiotic metabolites (i.e., postbiotics in pathological states) is controversial. Natural killer (NK) cells play a key role in innate and adaptive immunity. In this study, we examined NK cell activation influenced by a postbiotics mixture in response to gut microbiome modulation in stress-induced mice. In vivo activation of NK cells increased in the postbiotics mixture treatment group in accordance with Th1/Th2 expression level. Meanwhile, the Red Ginseng treatment group, a reference group, showed very little expression of NK cell activation. Moreover, the postbiotics mixture treatment group in particular changed the gut microbiome composition. Although the exact role of the postbiotics mixture in regulating the immune system of stress-induced mice remains unclear, the postbiotics mixture-induced NK cell activation might have affected gut microbiome modulation.

• Archives of Pharmacal Research
• /
• 제28권11호
• /
• pp.1282-1286
• /
• 2005

The in vivo immunomodulatory function of the activity of murine natural killer (NK) cells induced by high mannuronic acid-containing alginate (HMA) was examined. HMA was injected i.p at doses of 25 and 100 mg/kg. The NK activity was 3 times higher with 100 mg/kg HMA than the baseline. In addition, in vitro studies of splenocytes cultured with HMA for 20 h showed a significant increase in NK activity at E:T ratio of 100: 1; a 160$\%$ and 210$\%$ increase at 10 and 100 $\mu$g/mL, respectively. There was a six fold increase in interferon-$\gamma$ production in a postculture of splenocytes with 100 $\mu$g/mL HMA. HMA had no suppressive effects on the lymphocyte function in the presence or absence of mitogens. This suggests that HMA is useful in cancer immunotherapy.