MTDH促进头颈鳞癌细胞放疗抵抗的实验研究

MTDH promotes radioresistance in squamous cell carcinoma of the head and neck in vitro

摘要:

目的探讨星形胶质细胞上调基因1（astrocyte elevated gene1，AEG1，又称MTDH）对头颈部鳞状细胞癌（简称头颈鳞癌）放疗抵抗的影响。方法Western blotting检测放射线照射后头颈鳞癌细胞MTDH蛋白表达的改变。通过脂质体转染的MTDH cDNA和慢病毒介导的MTDH shRNA，分别在不同头颈鳞癌细胞中过表达和抑制MTDH，平板集落形成实验检测头颈鳞癌细胞放疗抵抗能力的改变，细胞免疫荧光染色检测DNA双链损伤指标γH2AX的表达。结果MTDH在头颈鳞癌细胞中的表达随着放射性照射剂量的增加和时间的延长逐渐升高。在CNE2细胞中过表达MTDH，其体外集落形成能力增强；相反，在Tu686细胞中抑制MTDH的表达，其体外集落形成能力减弱。同时，细胞免疫荧光显示Tu686细胞在MTDH抑制后，其DNA双链损伤指标γH2AX的表达增加，表明DNA双链损伤修复过程受阻。结论MTDH能促进头颈鳞癌细胞放疗抵抗的形成，与其对DNA双链损伤修复的调控作用相关。

关键词:头颈部鳞状细胞癌|MTDH|放疗抵抗|DNA双链损伤

Abstract:

ObjectiveTo study the function of mitochondria dehydrogenase (MTDH) on the radioresistance in squamous cell carcinoma of the head and neck (SCCHN).MethodsWestern blotting was used to check the dynamic change of MTDH protein in SCCHN cells exposed to irradiation. The expression of MTDH was upregulated with Lipofectaminemediated MTDH cDNA, and inhibited with lentivirusmediated MTDH shRNA. Then plate colony formation assay was applied to examine the alteration of radioresistant capacity. Immunofluorescence was done to detect the expression of γH2AX, which was a surrogate marker of DNA doublestrand breaks.ResultsThe expression of MTDH protein was increased after irradiation, which displayed an irradiation dosedependent and timedependent manner. MTDH overexpression in CNE2 cells resulted in enhanced ability to form colony on plate. On the contrary, inhibition the expression of MTDH in SCCHN Tu686 cells led to declined ability of plate colony formation, which was accompanied by increased γH2AX foci formation.ConclusionMTDH promotes radioresistance of SCCHN via modulating the repair process of DNA double strand breaks.

Key words:Squamous cell carcinoma| head and neck| MTDH| Radioresistance| DNA double strand break