High Serum Levels of Cholesterol Increase Antitumor Functions of Nature Killer Cells and Reduce Growth of Liver Tumors in Mice
High Serum Levels of Cholesterol Increase Antitumor Functions of Nature Killer Cells and Reduce Growth of Liver Tumors in Mice
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高血清水平的胆固醇可增强自然杀伤细胞的抗肿瘤功能并减少小鼠肝脏肿瘤的生长
DOI：
10.1053/j.gastro.2020.01.028
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发表时间：
2020-05-01
期刊：
影响因子：
29.4
通讯作者：
Wang, Hong-Yang
中科院分区：
文献类型：
--
作者：
Qin, Wen-Hao;Yang, Zhi-Shi;Wang, Hong-Yang
背景和目的血清胆固醇水平与肝细胞癌（HCC）发生发展的关系尚不清楚.我们调查了血清胆固醇水平对小鼠肝肿瘤发展的影响。MethodsWe进行了研究与C57 BL/6 J小鼠，小鼠与破坏的低密度脂蛋白受体基因（Ldlr−/−小鼠），和小鼠与条件性删除的自然杀伤（NK）细胞（NKdelemice）。给一些C57 BL/6 J和NKdelemice注射二乙基亚硝胺以诱导肝肿瘤形成。将小鼠置于正常饮食（ND）或高胆固醇饮食（HCD）以诱导高血清胆固醇水平。我们还研究了ApoE纯合子破坏的小鼠（ApoE−/−小鼠），它们自发地产生高血清胆固醇。在ND或HCD上的C57 BL/6 J和NKdelemice植入Hep 1 -6（小鼠肝癌）细胞，并监测异种移植肿瘤的生长和肺转移。从小鼠中收集血液样品并通过生物化学和流式细胞术进行分析;收集肝脏和肿瘤组织并通过组织学、免疫组织化学和RNA测序分析进行分析。从小鼠中分离NK细胞，并分析其胆固醇含量、脂筏形成、免疫信号传导和功能变化。我们从30例HCC患者和40例健康志愿者的血液样本中获得匹配的肿瘤组织和血液样本;测量胆固醇水平和NK细胞的细胞毒性。结果HCD和ApoE −/−小鼠的胆固醇水平高的C57 BL/6 J小鼠在二乙基亚硝胺注射或Hep 1 -6细胞植入后比ND小鼠发生更少和更小的肝肿瘤和肺转移。与ND喂养小鼠的肿瘤相比，HCD喂养小鼠和ApoE −/−小鼠的肝脏肿瘤中NK细胞数量增加。在注射二乙基亚硝胺或植入Hep 1 -6细胞后，ND组和HCD组的NK细胞缺失小鼠或基于抗体的NK细胞耗竭小鼠显示出相似的肿瘤数量和大小。从喂食HCD的C57 BL/6 J小鼠中分离的NK细胞增加了NK细胞活化受体的表达（天然细胞毒性触发受体1和天然杀伤组2，成员D），效应子功能的标志物（颗粒酶B和穿孔素）以及细胞因子和趋化因子与来自ND小鼠的NK细胞的比较;这些NK细胞还具有增强的针对小鼠肝癌细胞的细胞毒活性、积累的胆固醇、增加的脂筏形成和免疫信号传导激活。与ND-fedLdlr −/−小鼠相比，从HCD-fedLdlr −/−小鼠中分离的NK细胞没有增加胆固醇含量或对小鼠肝癌细胞的细胞毒性活性。血清胆固醇水平与从人HCCs. ConclusionsMouse分离的NK细胞的数量和活性增加血清胆固醇水平，由于HCD或ApoE的遗传破坏发展肝癌细胞或化学致癌物注射后，更少，更小的肿瘤。我们发现胆固醇在NK细胞中积累并激活其对肝癌细胞的效应功能。可以开发增加NK细胞的胆固醇摄取的策略用于治疗HCC。
Background and AimsThe relationship between serum cholesterol level and development of hepatocellular carcinoma (HCC) remains unclear. We investigated the effects of serum cholesterol level on development of liver tumors in mice.MethodsWe performed studies with C57BL/6J mice, mice with disruption of the low-density lipoprotein receptor gene (Ldlr−/−mice), and mice with conditional deletion of nature killer (NK) cells (NKdelemice). Some C57BL/6J and NKdelemice were given injections of diethylinitrosamine to induce liver tumor formation. Mice were placed on a normal diet (ND) or high-cholesterol diet (HCD) to induce high serum levels of cholesterol. We also studied mice with homozygous disruption ofApoE(ApoE−/−mice), which spontaneously develop high serum cholesterol. C57BL/6J and NKdelemice on the ND or HCD were implanted with Hep1-6 (mouse hepatoma) cells and growth of xenograft tumors and lung metastases were monitored. Blood samples were collected from mice and analyzed by biochemistry and flow cytometry; liver and tumor tissues were collected and analyzed by histology, immunohistochemistry, and RNA-sequencing analysis. NK cells were isolated from mice and analyzed for cholesterol content, lipid raft formation, immune signaling, and changes in functions. We obtained matched tumor tissues and blood samples from 30 patients with HCC and blood samples from 40 healthy volunteers; levels of cholesterol and cytotoxicity of NK cells were measured.ResultsC57BL/6J mice on HCD andApoE−/−mice with high serum levels of cholesterol developed fewer and smaller liver tumors and lung metastases after diethylinitrosamine injection or implantation of Hep1-6 cells than mice on ND. Liver tumors from HCD-fed mice andApoE−/−mice had increased numbers of NK cells compared to tumors from ND-fed mice. NKdelemice or mice with antibody-based depletion for NK cells showed similar tumor number and size in ND and HCD groups after diethylinitrosamine injection or implantation of Hep1-6 cells. NK cells isolated from C57BL/6J mice fed with HCD had increased expression of NK cell–activating receptors (natural cytotoxicity triggering receptor 1 and natural killer group 2, member D), markers of effector function (granzyme B and perforin), and cytokines and chemokines compared with NK cells from mice on ND; these NK cells also had enhanced cytotoxic activity against mouse hepatoma cells, accumulated cholesterol, increased lipid raft formation, and immune signaling activation. NK cells isolated from HCD-fedLdlr−/−mice did not have increased cholesterol content or cytotoxic activity against mouse hepatoma cells compared with ND-fedLdlr−/−mice. Serum levels of cholesterol correlated with number and activity of NK cells isolated from human HCCs.ConclusionsMice with increased serum levels of cholesterol due to an HCD or genetic disruption ofApoEdevelop fewer and smaller tumors after injection of hepatoma cells or a chemical carcinogen. We found cholesterol to accumulate in NK cells and activate their effector functions against hepatoma cells. Strategies to increase cholesterol uptake by NK cells can be developed for treatment of HCC.