野生型p53对涎腺多形性腺瘤细胞突变基因的修复

目的检测涎腺多形性腺瘤基因突变方式及野生型p53对突变基因的修复。方法留取4例涎腺多形性腺瘤新鲜标本，进行原代细胞培养。采用野生型p53基因转染培养细胞，通过逆转录聚合酶链反应检测转染后的基因表达。提取转染后各例细胞DNA及对应的肿瘤组织DNA，分别进行PCR反应扩增，聚丙烯酰胺凝胶电泳及核酸序列测定分析。结果PCR-单链构象多态性分析显示，3例出现异常电泳带。核酸序列测定结果显示，第6外显子的第203号密码子点突变；第8外显子的第272至290号密码子之间出现碱基缺失和碱基插入。野生型p53转染后的细胞DNA序列分析显示，p53第6和第8外显子的5个突变位点均恢复正常。结论涎腺多形性腺瘤发生过程中具有较高频率的p53基因突变，突变方式多样，涉及多个密码子；外源性野生型p53可有效地修复涎腺多形性腺瘤细胞中突变的p53基因位点。

wt-p53 gene repair for p53 mutations of salivary pleomorphic adenoma cells

OBJECTIVE: To analyze the original mutated codon of p53 gene of salivary pleomorphic adenoma (SPA) and to evaluate the repair effects of wt-p53 on SPA cells. METHODS: Four cases of SPA were obtained from clinical fresh samples and SPA cells were separated and cultured, and then the cells were transduced by Ad-wt-p53. The cells and the corresponding tumor tissue DNA were extracted, PCR and single strand conformational polymorphism (SSCP) and DNA sequencing analysis were performed. RESULTS: PCR-SSCP analysis showed 3 out of 4 SPA with abnormal exon 8 and abnormal exon 6. DNA sequencing analysis showed that exon 6 point mutation was found at codon 203 (GTG-->GCG), poly-codon mutations were found in exon 8 at codon 272 (GTG-->GT square), 275 (TGT-->T squareT), 276 (GCC--> squareCC) and at codon 290 (CGC-->CGCC). After transduced by Ad-wt-p53, all of the mutated codons were repaired. CONCLUSIONS: p53 gene mutation involved many codons that occurred frequently in the tumorigenesis of SPA. Exogenous wt-p53 could compensate and repair all the mutated p53 codons of SPA cells. SPA cells transduced by Ad-wt-p53 showed the typical apoptosis.