Van Leeuwen I S, Hellmèn E, Cornelisse C J, Van den Burgh B, Rutteman G R
Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, University of Utrecht, The Netherlands.
Anticancer Res. 1996 Nov-Dec;16(6B):3737-44.
Alterations in the p53 gene are frequently observed in a wide variety of human cancers. To elucidate the role of p53 in tumorigenesis of the dog, we analyzed nine mammary tumor cell lines, and the primary or metastatic tumors used for their establishment, for the presence of genomic p53 abnormalities. Possible genomic rearrangements were analyzed by Southern blotting using a canine cDNA probe. More subtle alterations were identified by single strand conformation polymorphism (SSCP) analysis for which we partially characterized the canine p53 gene (codon 109-388 as compared to the human gene). The presence of mutations in SSCP fragments with altered mobility was confirmed by DNA sequencing. Three of the nine cell lines showed a mutated p53 gene. All were missense mutations accompanied by loss of the wild type allele. The point mutations, at codon 176 (TGC * TTC), 236 (TAC * AAC) and 245 (GGC * GCC), were all located in one of the four regions that are frequently affected in human cancers. Analysis of the DNA extracted from the tumors of origin demonstrated the presence of two of these point mutations. These findings indicate the involvement of the p53 gene in the genesis of canine tumors in a way comparable to that of human tumors.
p53基因的改变在多种人类癌症中经常被观察到。为了阐明p53在犬肿瘤发生中的作用，我们分析了9种乳腺肿瘤细胞系以及用于建立这些细胞系的原发性或转移性肿瘤，以检测基因组p53异常的存在情况。使用犬cDNA探针通过Southern印迹法分析可能的基因组重排。通过单链构象多态性（SSCP）分析鉴定更细微的改变，为此我们对犬p53基因（与人基因相比，密码子109 - 388）进行了部分特征分析。通过DNA测序证实了迁移率改变的SSCP片段中存在突变。9个细胞系中的3个显示p53基因发生突变。所有都是错义突变并伴有野生型等位基因的缺失。密码子176（TGC * TTC）、236（TAC * AAC）和245（GGC * GCC）处的点突变均位于人类癌症中经常受影响的四个区域之一。对源自肿瘤的DNA分析表明存在其中两个点突变。这些发现表明p53基因以与人类肿瘤类似的方式参与犬肿瘤的发生。
