Su Zhixiong, Ye Xinping, Shang Liming
Department of General Surgery, Second Affiliated Hospital of Guangxi Medical University, Nanning, China.
Department of Hepatobiliary Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, China.
Yonsei Med J. 2019 Jan;60(1):22-29. doi: 10.3349/ymj.2019.60.1.22.
It is well documented that natural killer (NK) cytotoxicity against hepatocellular carcinoma (HCC) cells is impaired in HCC, which might account for the failure of anti-tumor immune response. miRNAs are considered as important regulators for the development and functions of NK cells. However, the entire role of miR-506 in NK cells remains far from being addressed.
The expressions of miR-506 and signal transducer and activator of transcription 3 (STAT3) mRNA in primary NK cells from HCC patients and healthy controls were detected by quantitative real-time PCR. NK cell cytotoxicity was assessed by CFSE/7AAD cytotoxicity assay and lactate dehydrogenase assay. Luciferase reporter assay, RNA immunoprecipitation assay, and western blot were conducted to confirm the interaction between miR-506 and STAT3.
miR-506 expression was downregulated and STAT3 mRNA was upregulated in primary NK cells from HCC patients. Primary NK cells from HCC patients showed remarkably reduced cytotoxicity against SMMC7721 or HepG2 cells. NK cell cytotoxicity was positively correlated with miR-506 expression and negatively correlated with STAT3 mRNA expression. Additionally, miR-506 overexpression enhanced NK cell cytotoxicity against HCC cells, while miR-506 inhibitor showed the reverse effect. Moreover, miR-506 could suppress STAT3 expression by directly targeting 3'-untranslated regions of STAT3. A negative correlation between miR-506 and STAT3 mRNA expression in HCC patients was observed. Mechanistically, overexpressing STAT3 greatly reversed miR-506-mediated promotion of NK cell cytotoxicity against HCC cells.
miR-506 enhanced NK cell cytotoxicity against HCC cells by targeting STAT3, suggesting that modulating miR-506 expression maybe a promising approach for enhancing NK cell-based antitumor therapies.
有充分文献记载，在肝癌中自然杀伤（NK）细胞对肝癌（HCC）细胞的细胞毒性受损，这可能是抗肿瘤免疫反应失败的原因。微小RNA（miRNA）被认为是NK细胞发育和功能的重要调节因子。然而，miR-506在NK细胞中的整体作用仍远未得到阐明。
采用定量实时PCR检测肝癌患者和健康对照者原代NK细胞中miR-506和信号转导及转录激活因子3（STAT3）mRNA的表达。通过CFSE/7AAD细胞毒性测定法和乳酸脱氢酶测定法评估NK细胞的细胞毒性。进行荧光素酶报告基因测定、RNA免疫沉淀测定和蛋白质免疫印迹以证实miR-506与STAT3之间的相互作用。
肝癌患者原代NK细胞中miR-506表达下调，STAT3 mRNA表达上调。肝癌患者的原代NK细胞对SMMC7721或HepG2细胞的细胞毒性显著降低。NK细胞的细胞毒性与miR-506表达呈正相关，与STAT3 mRNA表达呈负相关。此外，miR-506过表达增强了NK细胞对肝癌细胞的细胞毒性，而miR-506抑制剂则表现出相反的效果。而且，miR-506可通过直接靶向STAT3的3'非翻译区来抑制STAT3表达。在肝癌患者中观察到miR-506与STAT3 mRNA表达之间呈负相关。机制上，过表达STAT3极大地逆转了miR-506介导的NK细胞对肝癌细胞细胞毒性的促进作用。
miR-506通过靶向STAT3增强了NK细胞对肝癌细胞的细胞毒性，提示调节miR-506表达可能是增强基于NK细胞的抗肿瘤治疗的一种有前景的方法。
