Matozaki T, Sakamoto C, Matsuda K, Suzuki T, Konda Y, Nakano O, Wada K, Uchida T, Nishisaki H, Nagao M
Second Department of Internal Medicine, Kobe University School of Medicine, Japan.
Biochem Biophys Res Commun. 1992 Jan 15;182(1):215-23. doi: 10.1016/s0006-291x(05)80133-0.
To investigate the molecular pathogenesis of human gastric cancers the p53 gene, a suppressor oncogene, was analyzed in 12 human gastric cell lines. Southern blot and Northern blot analysis revealed a total deletion of p53 gene in KATO-III cells but no major abnormality of p53 gene in other cell lines. By the use of the reverse-transcriptase polymerase chain reaction and direct sequencing 7 cell lines showed point mutations of p53 gene resulting in amino-acid substitutions. Most of them were rare mutations which had not been observed in other types of cancers. One of these mutations was also detected through the use of PCR and oligomer-specific hybridization. Six out of 7 cell lines with mutations of p53 gene also lost one allele of chromosome 17p. Immunoblotting of cell lysates with an antibody specific to p53 demonstrated the absence of p53 protein in KATO-III cell. By contrast, the high levels of the p53 protein were observed in 5 cell lines all of which contained mutations of p53 gene. These results further suggest that the inactivation of p53 gene may play an important role in the transformation of gastric cells to the malignant phenotype. KATO-III cells might be a good model for studying the significance of the loss of p53 gene in cellular transformation.
为了研究人类胃癌的分子发病机制，对12种人类胃细胞系中的一种抑癌基因——p53基因进行了分析。Southern印迹和Northern印迹分析显示，KATO - III细胞系中p53基因完全缺失，而其他细胞系中p53基因无重大异常。通过逆转录聚合酶链反应和直接测序，7种细胞系显示p53基因存在点突变，导致氨基酸替换。其中大多数是罕见突变，在其他类型癌症中未观察到。通过使用聚合酶链反应和寡核苷酸特异性杂交也检测到其中一种突变。7种p53基因突变的细胞系中有6种也丢失了17号染色体短臂的一个等位基因。用p53特异性抗体对细胞裂解物进行免疫印迹分析显示，KATO - III细胞中不存在p53蛋白。相比之下，在所有含有p53基因突变的5种细胞系中均观察到高水平的p53蛋白。这些结果进一步表明，p53基因的失活可能在胃细胞向恶性表型的转化中起重要作用。KATO - III细胞可能是研究p53基因缺失在细胞转化中的意义的良好模型。
