ABNORMAL STRUCTURE AND EXPRESSION OF P53 GENE IN HUMAN HEPATOCELLULAR-CARCINOMA
ABNORMAL STRUCTURE AND EXPRESSION OF P53 GENE IN HUMAN HEPATOCELLULAR-CARCINOMA
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DOI：
10.1073/pnas.87.5.1973
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发表时间：
1990-03-01
影响因子：
11.1
通讯作者：
OZTURK, M
中科院分区：
文献类型：
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作者：
BRESSAC, B;GALVIN, KM;OZTURK, M
关于肝癌发生的分子机制的信息很少。我们研究了p53基因在DNA，RNA和蛋白质水平在7个人肝细胞癌（HCC）衍生的细胞系，6个显示p53异常。Southern杂交结果显示，Hep 3B细胞中p53基因部分缺失，SK-HEP-1细胞中p53基因重排。在Hep 3B和FOCUS细胞中检测不到p53基因的转录物，FOCUS细胞中没有明显的p53基因缺失或重排。[35 S]甲硫氨酸标记肝癌细胞后的免疫沉淀表明，p53蛋白在Hep 3B和FOCUS中不存在，而在PLC/PRF/5细胞中浓度降低。Mahlavu细胞合成的p53在SDS/聚丙烯酰胺凝胶上迁移较慢，表明它是一种异常蛋白。在Huh 7细胞中，p53蛋白具有延长的半衰期，导致其在细胞核中的积累;免疫印迹法也发现p53蛋白水平增加。在肝母细胞瘤衍生的Hep-G2细胞系中，p53基因及其表达似乎没有改变。我们发现，p53表达的丧失并没有发生在FOCUS细胞系的体外晚期事件，因为p53蛋白在早期传代时也检测不到。我们的结论是，p53表达的损失或异常形式的蛋白质的存在下，经常与肝癌细胞系。这些观察结果表明，p53的改变可能是肝细胞恶性表型转化的重要事件。
There is little information regarding the molecular mechanisms of hepatocarcinogenesis. We studied the p53 gene at the DNA, RNA, and protein level in seven human hepatocellular carcinoma (HCC)-derived cell lines; six of seven showed p53 abnormalities. By Southern blotting, the p53 gene was found to be partially deleted in Hep3B and rearranged in SK-HEP-1 cells. Transcripts of the p53 gene were undetectable in Hep3B as well as in FOCUS cells that had no apparent deletion or rearrangement of the p53 gene. Immunoprecipitation after [35S]methionine labeling of HCC cells demonstrated that p53 protein was absent in Hep3B and FOCUS and reduced in concentration in PLC/PRF/5 cells. p53 synthesized by Mahlavu cells showed a slower migration on SDS/polyacrylamide gels suggesting it was an abnormal protein. In Huh7 cells, p53 protein had a prolonged half-life leading to its accumulation in the nuclei; increased levels of p53 protein were also found by immunoblotting. The p53 gene and its expression appeared to be unaltered in the hepatoblastoma-derived Hep-G2 cell line. We found that the loss of p53 expression did not occur as a late in vitro event in the FOCUS cell line because p53 protein was also nondetectable at an early passage. We conclude that the loss of p53 expression or the presence of abnormal forms of the protein are frequently associated with HCC cell lines. These observations suggest that alterations in p53 may be important events in the transformation of hepatocytes to the malignant phenotype.