Hrad17在头颈肿瘤中表达下降的研究

Study on Decrease in Hrad17 Expression in Head and Neck Squamous Carcinoma

目的 DNA损伤修复基因在维持细胞稳定性的作用及头颈肿瘤表现染色体不稳定性研究。方法应用基因表达芯片在7例头颈肿瘤和6例正常口腔粘膜中筛查表达下调的基因,用实时定量RT-PCR证实基因芯片的结果,蛋白印迹检测蛋白表达,定量PCR检测其DNA拷贝数。结果 Hrad17是发现下调的基因之一,Z-score和倍数变化分别为-2.5和0.39,定量RT-PCR显示肿瘤组织中Hrad17 mRNA表达下降,均值为0.216 6,而正常粘膜为0.395 7(P<0.05)。Western印迹显示Hrad17蛋白在肿瘤组织中检测不到(0/12),而在正常口腔粘膜组织中表达很强(6/7)。定量PCR显示Hrad17DNA在大多数头颈肿瘤组织中下降。结论 Hrad17表达的缺失经常出现在头颈鳞癌中,由于基因的缺失并可能导致头颈鳞癌基因组的不稳定性,导致肿瘤发生。

Objective DNA repair genes play a critical role in maintaining gene stability.Significance of head and neck squamous cell carcinoma（HNSCC） shows chromosomal instability.Methods Microarrays was applied to 7 samples of primary HNSCC and 6 samples of normal control oral epithelial tissue.Additional confirmation was performed by quantitative RT-PCR in these samples and followed by western blot,quantitative PCR at the Hrad17 locus.Results Hrad17 was one of the downregulated checkpoint genes in primary head and neck tumor tissue.Its Z-score and fold change were-2.5 and 0.39,respectively.The results of normalized,quantitative RT-PCR showed decreased expression of Hrad17 mRNA in tumor tissue（mean value 0.2166） when compared with normal tissue（mean value 0.3957,p 0.05）.Western blot demonstrated undetectable expression of Hrad17 protein in primary tumor tissue（0/12）,while there was strong expression of Hrad17 protein in normal oral mucosal tissue（6/7）.Quantitative PCR showed that Hrad17 DNA copy number was decreased in the majority of head and neck tumor tissue samples.Conclusion Loss of Hrad17 expression occurs frequently in HNSCC,is often due to genomic deletion,and may facilitate genomic instability in HNSCC and carcinogenesis.