MNX1通过调控ATG7诱导细胞自噬介导鼻咽癌放疗抵抗

MNX1 induces autophagy by regulating ATG7 to mediate radiotherapy resistance in nasopharyngeal carcinoma

目的探讨MNX1通过调控ATG7诱导细胞自噬介导鼻咽癌放疗抵抗的作用机制。方法采用人鼻咽癌抗辐射细胞系HONE-1-IR和辐射敏感细胞系HONE-1进行体外分析;检测细胞中MNX1的表达水平,比较自噬标志物LC3Ⅱ、ATG7和p62表达情况;并分析MNX1与ATG7调控细胞自噬的关系。结果与HONE-1细胞相比,HONE-1-IR细胞中MNX1 m RNA和蛋白水平均升高,LC3Ⅱ、ATG7和p62蛋白表达水平同样升高(P<0.05);下调MNX1抑制了自噬体的形成(P<0.05)。与阴性对照组相比,转染si MNX1的细胞增殖率和细胞活力明显降低(P<0.05);细胞集落形成率明显降低(P<0.05)。下调MNX1明显阻断了自噬体的形成,上调ATG7后,自噬体的抑制水平恢复到对照组的水平(P<0.05);在HONE-1-IR细胞中通过下调MNX1抑制了细胞的增殖和活力,而通过上调ATG7逆转了这种抑制(P<0.05)。结论MNX1通过上调ATG7调控细胞自噬参与放疗抵抗,通过敲低MNX1-ATG7轴可提高放疗抵抗细胞的敏感性,MNX1可作为增强放射敏感性的潜在治疗靶点。

Objective To investigate the mechanism of MNX1 inducing autophagy by regulating ATG7 to mediate radiotherapy resistance of nasopharyngeal carcinoma.Methods The radiation-resistant cell line HONE-1-IR and radiation-sensitive cell line HONE-1 were used for in vitro analysis.MNX1 expression was detected,and the expression of autophagy markers LC3Ⅱ,ATG7 and p62 was compared.The relationship between MNX1 and ATG7 regulation of autophagy was analyzed.Results Compared with HONE-1 cells,MNX1 m RNA and protein levels were increased in HONE-1-IR cells,and LC3Ⅱ,ATG7 and p62 protein levels were increased in HONE-1-IR cells(P<0.05).Down-regulation of MNX1 inhibited the formation of autophagosomes(P<0.05).Compared with the negative control group,the proliferation rate and cell viability of si MNX1 transfected cells were significantly decreased(P<0.05).The colony formation rate of transfected si MNX1 cells was significantly lower than that of the negative control group(P<0.05).Down-regulation of MNX1 significantly blocked the formation of autophagosomes,and up-regulation of ATG7 restored the inhibitory level of autophagosomes to the level of control group(P<0.05).The proliferation and viability of HONE-1-IR cells were inhibited by down-regulation of MNX1,while the inhibition was reversed by up-regulation of ATG7(P<0.05).Conclusion MNX1 regulates autophagy to participate in radiotherapy resistance by upregulating ATG7,and the sensitivity of radiotherapy resistant cells can be improved by knocking down the MNX1-ATG7 axis.MNX1 can be used as a potential therapeutic target to enhance radiotherapy sensitivity.