p53 mutations selected in vivo when mouse mammary epithelial cells form hyperplastic outgrowths are not necessary for establishment of mammary cell lines in vitro.
p53 mutations selected in vivo when mouse mammary epithelial cells form hyperplastic outgrowths are not necessary for establishment of mammary cell lines in vitro.
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发表时间：
1993-04
期刊：
影响因子：
11.2
通讯作者：
M. A. Ozbun;Jerry Dj;F. Kittrell;D. Medina;J. Butel
中科院分区：
文献类型：
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作者：
M. A. Ozbun;Jerry Dj;F. Kittrell;D. Medina;J. Butel
乳腺癌是长期发生多种改变的结果。肿瘤发生早期阶段的遗传变化尚未确定。最近开发的小鼠系统允许在体内和体外研究乳腺癌前细胞(F.S.Kittrell等人，Cancer Res.，52：1924-1932，1992)。为了评估 p53 突变在乳腺癌早期阶段的潜在作用，在一系列小鼠乳腺上皮细胞系中测定了 p53 的状态，这些细胞系在移植到同系小鼠的清除的乳腺脂肪垫中时会产生肿瘤前生长（增生性肺泡结节）。使用免疫沉淀和免疫化学测定分析蛋白质稳定性和构象；使用聚合酶链式反应方法对 p53 转录本进行测序。亲本细胞系（FSK 系）在蛋白质或核酸水平上均未显示 p53 改变的证据，表明 p53 突变对于体外乳腺上皮细胞系的建立不是必需的。相反，源自FSK细胞诱导的增生性肺泡结节生长的细胞系（TM系）仅表达突变的p53基因。一种生长细胞系 (TM-2H) 中的突变导致 p53 蛋白合成丧失，而另外两种生长细胞系 (TM-3、TM-4) 过度表达突变 p53 蛋白。 p53 突变似乎与体内肿瘤前生长相关。尽管尚不清楚这些突变是发生在体内细胞移植之前还是之后，但表达突变型 p53 的细胞似乎在乳腺中具有明显的生长优势。
Breast cancer is a consequence of multiple alterations occurring over a long period of time. Genetic changes in early stages of tumorigenesis have not been defined. A recently developed murine system permits the study of mammary preneoplastic cells in vivo and in vitro (F. S. Kittrell et al., Cancer Res., 52: 1924-1932, 1992). To assess the potential role of p53 mutations in early stages of breast cancer, the status of p53 was determined in a series of mouse mammary epithelial cell lines which give rise to preneoplastic outgrowths (hyperplastic alveolar nodules) when transplanted into cleared mammary fat pads of syngeneic mice. Protein stability and conformation were analyzed using immunoprecipitations and immunochemical assays; p53 transcripts were sequenced using a polymerase chain reaction approach. The parental cell lines (FSK lines) showed no evidence of p53 alterations at either the protein or the nucleic acid level, indicating that p53 mutations are not essential for the establishment of mammary epithelial cell lines in vitro. In contrast, cell lines (TM lines) derived from hyperplastic alveolar nodule outgrowths induced by FSK cells expressed only mutant p53 genes. The mutation in one outgrowth cell line (TM-2H) resulted in the loss of p53 protein synthesis, whereas two other outgrowth lines (TM-3, TM-4) overexpressed mutant p53 protein. Mutation of p53 appears to correlate with preneoplastic growth in vivo. Although it is not clear if the mutations occur before or after transplantation of cells in vivo, there appears to be a pronounced growth advantage in the mammary gland for cells expressing mutant p53.