miR-16/15a^(-/-)小鼠NK细胞功能及其对结肠癌移植瘤敏感度分析

Analysis of NK cell function in miR-16/15a^(-/-)mice and its sensitivity to colon transplanted tumor

目的:观察miR-16是否通过调节NKG2D表达而影响自然杀伤(natural killer,NK)细胞的生物学功能及其抗肿瘤活性。方法:miR-16/15a^(-/-)小鼠和对照小鼠经皮下注射MC38细胞制备结肠癌移植瘤模型,观察两组小鼠皮下实体瘤生长情况;比较普通小鼠生理或荷瘤状态下NK1.1+NKG2D+细胞和NK1.1+NKG2D-细胞内miR-16的表达;分析生理及荷瘤状态下miR-16/15a^(-/-)小鼠NK细胞NKG2D表达、γ干扰素(interferon-γ,IFN-γ)分泌及细胞毒性作用。结果:与同品系小鼠比较,miR-16/15a^(-/-)小鼠中MC38结肠癌移植瘤的生长受到显著抑制,生理状态小鼠NK1.1+NKG2D+细胞miR-16的表达明显低于NK1.1+NKG2D-细胞,而在荷瘤小鼠来源的两组细胞中无明显差异;与野生型小鼠相比,生理及荷瘤状态下的miR-16/15a^(-/-)小鼠NK1.1+NKG2D+细胞的比例及NK细胞活性无明显变化。结论:miR-16/15a敲除抑制MC38结肠癌移植瘤生长,而miR-16/15a敲除小鼠体内NK细胞的比例及功能及荷瘤状态下NK细胞活性并无明显变化,提示miR-16/15a缺失并非通过NK细胞抑制MC38结肠癌移植瘤生长。

Objective:To investigate whether miR-16 affected the biological function and anti-tumor activity of natural killer(NK)cells by regulating NKG2D expression.Methods:The control mice and miR-16/15 a^(-/-)mice were subcutaneously injected with MC38 cells to prepare the colon cancer tumor model,and the growth of transplanted colon cancer in miR-16/15 a^(-/-)mice and control mice were observed.Then,the transcription level of miR-16 in NK1.1^(+)NKG2D^(+)cells and NK1.1^(+)NKG2D^(-)cells was compared under physiological or tumor-bearing conditions in wild-type mice.Finally,in comparison with wild-type mice,we analyzed NKG2D expression,interferon-γ(IFN-γ)production and cytotoxicity of NK cells in miR-16/15 a^(-/-)mice.Results:Compared with the control mice,the growth of MC38 transplanted tumor was significantly inhibited in miR-16/15 a^(-/-)mice.The transcription level of miR-16 in NK1.1^(+)NKG2D^(+)cells was significantly lower than that in NK1.1^(+)NKG2D^(-)cells in normal mice,while there was no significant difference between the two groups in tumor-bearing mice.Compared with the control mice,NK1.1^(+)NKG2D^(+)cell frequency and NK cell activity did not change significantly in miR-16/15 a^(-/-)mice.Conclusion:MiR-16/15a knockout inhibited the growth of MC38 transplanted tumor,while the ratio and function of NK cells in miR-16/15a knockout mice and the activity of NK cells in the tumor-bearing state did not significantly change,suggesting that miR-16/15a dificiency does not inhibit the growth of MC38 transplanted tumor though NK cells.