Abstract Context: Natural killer (NK) cells can eliminate malignant cells and play a vital role in immunosurveillance. Administration of natural compounds represents a promising approach for antitumor immunotherapy, which may enhance the NK cell activity via multiple mechanisms. Objective: Establishing approaches to evaluate the effect of select natural products on NK cell-mediated cytotoxicity. Materials and methods: We selected a natural product library containing 2880 pure compounds, which was provided by the National Centre for Drug Screening of China. 0.1% DMSO was employed as a negative control, and 100 U/mL human recombinant IL-2 was employed as a positive control. To evaluate the % of tumour cells which were killed by NK cells, expanded NK cells were co-cultured with tumour cells and then treated with natural products at the concentration of 10 μM. After 24-h co-incubation, luminescent signal was detected and percent lysis was calculated. Results: We report on the results of a three-round high-throughput screening effort that identified 20-deoxyingenol 3-angelate (DI3A) and its analogue ingenol 3-angelate (I3A) as immuno enhancers which boosts NK cell-mediated killing of non-small cell lung cancer cells (NSCLCs). Biophotonic cytotoxicity assay and calcein release assay were used as two well-established NK cell cytotoxicity detection assays to validate the immuno-enhancing effects of DI3A and I3A, which was achieved by increasing degranulation and interferon-gamma secretion of NK cells. Conclusions: Our newly established ATP-based method was a valuable and information-rich screening tool to investigate the biological effects of natural products on both NK cells and tumour cells.

中文翻译：

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用于筛选促进 NK 细胞介导的癌细胞杀伤的天然产物的高通量测定

摘要 背景：自然杀伤（NK）细胞可以清除恶性细胞，在免疫监视中发挥重要作用。天然化合物的给药代表了一种有前景的抗肿瘤免疫治疗方法，它可以通过多种机制增强 NK 细胞的活性。目的：建立评估精选天然产物对 NK 细胞介导的细胞毒性影响的方法。材料与方法：我们选择了一个包含2880个纯化合物的天然产物库，该库由国家药物筛选中心提供。0.1% DMSO 用作阴性对照，100 U/mL 人重组 IL-2 用作阳性对照。为了评估被 NK 细胞杀死的肿瘤细胞的百分比，扩增后的 NK 细胞与肿瘤细胞共培养，然后用 10 μM 浓度的天然产物处理。共孵育 24 小时后，检测到发光信号并计算裂解百分比。结果：我们报告了三轮高通量筛选工作的结果，该工作确定了 20-脱氧姜烯醇 3-当归酸 (DI3A) 及其类似物 3-当归姜酸酯 (I3A) 作为免疫增强剂，可促进 NK 细胞介导的非- 小细胞肺癌细胞 (NSCLC)。生物光子细胞毒性试验和钙黄绿素释放试验被用作两种成熟的 NK 细胞细胞毒性检测试验，以验证 DI3A 和 I3A 的免疫增强作用，这是通过增加 NK 细胞的脱粒和干扰素-γ 分泌来实现的。结论：