NK cell-produced IFN-γ regulates cell growth and apoptosis of colorectal cancer by regulating IL-15
NK cell-produced IFN-γ regulates cell growth and apoptosis of colorectal cancer by regulating IL-15
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DOI：
10.3892/etm.2019.8343
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发表时间：
2020-02-01
影响因子：
2.7
通讯作者：
Nan, Kejun
中科院分区：
文献类型：
--
作者：
Cui, Feng;Qu, Di;Nan, Kejun
在全球范围内，结直肠癌（CC）是与癌症相关的第三大死亡原因。自然杀伤（NK）细胞是负责消除肿瘤细胞和细胞因子产生的主要类别的细胞。NK细胞介导的干扰素γ（IFN-γ）的产生具有抗病毒、免疫调节和抗肿瘤特性。IL-15在将炎症与癌症联系起来方面很重要。例如，IL-15促进体液和细胞介导的免疫应答以抑制肿瘤生长。IL-15通过诱导抗肿瘤免疫抑制结肠炎相关结肠癌的发生然而，NK细胞介导的IFN-γ对CC进展中IL-15表达的影响仍然未知。采用逆转录-定量PCR和蛋白质印迹法分别检测mRNA和蛋白质水平。使用ELISA检测IFN-γ浓度。使用cytoTox 96（R）非放射性细胞毒性测定法检测NK-92细胞对SW 480细胞的细胞毒性。流式细胞术检测细胞凋亡，CCK-8法检测细胞增殖。IL-2用于NK-92刺激，IL-15抗体用于中和IL-15生物活性。在本研究中，21例CC患者和21名健康志愿者在西安交通大学第一附属医院入选。CC组NK细胞IL-15 mRNA和蛋白表达均显著低于健康志愿者组。IL-2除了增强NK-92细胞介导的对SW 480细胞的杀伤外，还增强IFN-γ的产生/分泌。与对照组相比，单独用IL-2处理的NK-92细胞显著增加细胞凋亡、BAX表达水平以及磷酸化（p）-Janus激酶2和p-STAT 1蛋白水平，同时降低SW 480细胞中的细胞活力和Bcl-2蛋白水平。当用IL-2和靶向IL-15的多克隆抗体（pAb）处理时，未观察到这些结果。总之，NK细胞介导的IFN-γ通过调节IL-15在CC中发挥关键作用。IL-2诱导的IFN-γ的作用被pAb IL-15处理消除。IFN-γ如何调节IL-2的作用机制尚不清楚，这是未来研究的一个有前途的领域。
Globally, colorectal cancer (CC) is the third leading cause of mortality associated with cancer. Natural killer (NK) cells are a major class of cells that are responsible for eliminating tumor cells and cytokine production. NK cell-mediated production of interferon gamma (IFN-gamma) has antiviral, immunoregulatory and anti-tumor properties. IL-15 is important in linking inflammation with cancer. For instance, IL-15 promotes humoral and cell-mediated immune responses to inhibit tumor growth. IL-15 inhibits colitis-associated colon carcinogenesis by inducing antitumor immunity. However, the effect of NK cell-mediated IFN-gamma on IL-15 expression in CC progression remains unknown. mRNA and protein level were detected using reverse transcription-quantitative PCR and western blotting, respectively. IFN-gamma concentrations were detected using ELISAs. The cytotoxicity of NK-92 cells on SW480 cells was detected using cytoTox 96 (R) non-radioactive cytotoxicity assays. Cell apoptosis and cell proliferation was detected using flow cytometry and CCK-8 assays, respectively. IL-2 was used for NK-92 stimulation, IL-15 antibodies were used to neutralize IL-15 bioactivity. For the present study, 21 patients with CC and 21 healthy volunteers were enrolled at the First Affiliated Hospital of Xi'an Jiaotong University. IL-15 mRNA and protein expression were significantly lower in NK cells isolated from the CC group compared with healthy volunteer group. IL-2 enhanced the production/secretion of IFN-gamma in addition to enhancing NK-92 cell-mediated killing of SW480 cells. Compared with the control group, NK-92 cells treated with IL-2 alone significantly increased cell apoptosis, BAX expression levels as well as phosphorylated (p)-Janus kinase 2 and p-STAT1 protein levels, whilst reducing cell viability and Bcl-2 protein levels in SW480 cells. These observations were not made when treated with IL-2 and polyclonal antibody (pAb) targeting IL-15. Taken together, NK cell-mediated IFN-gamma served a pivotal role in CC by regulating IL-15. The effects of IL-2 induced IFN-gamma were abolished by pAb IL-15 treatment. The mechanisms of action behind how IFN-gamma regulates IL-2 is unclear, and is a promising area for future research.