Dissemination and tissue invasiveness in murine acute leukemia associated with acquisition of p53 mutation and loss of wild-type p53.
Dissemination and tissue invasiveness in murine acute leukemia associated with acquisition of p53 mutation and loss of wild-type p53.
复制标题
小鼠急性白血病的传播和组织侵袭与 p53 突变的获得和野生型 p53 的丧失相关。
DOI：
10.1002/mc.2940130208
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发表时间：
1995
影响因子：
4.6
通讯作者：
Haas,M
中科院分区：
文献类型：
--
作者：
Hsiao,M;Wu,CY;Low,J;Pattengale,P;Yeargin,J;Haas,M
接受分剂量辐射治疗的小鼠中，约60%的小鼠出现了广泛扩散至全身的白血病，而接受分剂量辐射治疗的小鼠中，40%的小鼠出现了完全局限于胸腺的白血病。我们研究了p53在非培养胸腺白血病样本和由这些白血病建立的细胞系中的状态。在弥散性疾病小鼠中，还从内脏白血病器官中获得初级样本，并从这些白血病器官中建立细胞系以供进一步研究。利用单链构象多态性（SSCP）、核酸测序和免疫化学分析，研究人员发现，在10例弥散性白血病中，9例白血病细胞系发生了thp53等位基因突变；一个ep53等位基因与另一个野生型的突变发生在一个播散性白血病中。在每只小鼠的不同白血病器官建立的所有细胞系中都发现了每只小鼠特有的ap53突变。在每只小鼠的非培养白血病组织中也发现了相同的突变，表明突变起源于体内并且是克隆的。7例非播散性胸腺瘤中有7例仅具有野生型pep53。因此，体内传播和组织侵袭性与野生型pep53的丧失有关，这是由两个等位基因的突变或突变和杂合性的丧失引起的，这是由由它们建立的细胞系的研究揭示的。具有p53突变的白血病细胞在体内的选择性播散在体外也有类似的情况。携带播散性白血病小鼠的白血病细胞系比携带胸腺非播散性白血病小鼠的白血病细胞系更容易建立（成功率大于80%）（成功率小于10%）。此外，尽管具有播散性白血病的小鼠携带野生型和编码突变p53的胸腺瘤细胞的混合物，但只有含有突变p53的细胞系在培养中得以建立。在胸腺瘤细胞系中发现的突变总是通过从非培养的胸腺瘤组织中提取的DNA的SSCP和测序检测到的。然而，在非培养的内脏器官白血病组织中，从它们建立的细胞系中发现的克隆alp53突变通常无法通过SSCP或测序检测到，但可以通过免疫化学分析或聚合酶链反应扩增检测到。这表明白血病组织中存在的野生型基因对突变基因的掩蔽程度出乎意料。即使在比正常器官大得多的白血病器官中，掩蔽也很明显。因此，通过SSCP和测序对白血病组织进行常规筛查可能会严重低估p53突变的发生率。广泛报道的人类肿瘤中肿瘤抑制基因（如p16INK4）的丢失与肿瘤细胞系中肿瘤抑制基因丢失的发生率之间的差异，部分可能是由于类似的检测困难。©1995 Wiley‐Liss, Inc。
Approximately 60% of mice treated with split‐dose radiation develop leukemias that disseminate widely through the body, whereas 40% of the treated mice incur leukemias that are contained entirely within the thymus. We studied the status ofp53in non‐cultured samples of thymic leukemias and in cell lines established from these leukemias. In those mice with disseminated disease, primary samples were also obtained from visceral leukemic organs, and cell lines were established from these leukemic organs for further study. Using single‐strand conformation polymorphism (SSCP), nucleic acid sequencing, and immunochemical analysis, we found that mutation of bothp53alleles occurred in leukemic cell lines developed from nine of 10 disseminated leukemias; mutation of onep53allele with the other remaining wild‐type occurred in one disseminated leukemia. Ap53mutation unique for each mouse was found in all cell lines established from the different leukemic organs of each mouse. The same mutation was also found in the non‐cultured leukemic tissues of each mouse, indicating that the mutations originated in vivo and were clonal. Seven of seven non‐disseminating thymomas possessed wild‐typep53only. Hence, in vivo dissemination and tissue invasiveness were associated with the loss of wild‐typep53by mutation of both alleles or by mutation and loss of heterozygosity, as revealed by studies of cell lines established from them. The selective in vivo dissemination of leukemia cells possessingp53mutations had a parallel in vitro. Leukemia cell lines from mice harboring disseminating leukemia were established more readily (success rate greater than 80%) than lines from mice harboring thymic nondisseminating leukemia (success rate less than 10%). Additionally, while mice with disseminating leukemia harbored a mixture of wild‐type and mutantp53—encoding thymoma cells, only cell lines possessing mutantp53became established in culture. Mutations found in thymoma cell lines were always detectable by SSCP and sequencing of DNA extracted from non‐cultured thymoma tissue. However, in non‐cultured leukemic tissue of visceral organs, the clonalp53mutations found in cell lines established from them were often not detectable by SSCP or sequencing but were detectable by immunochemical analysis or polymerase chain reaction amplification. This indicates an unexpected degree of masking of mutant genes by wild‐type genes present in the leukemic tissue. Masking was evident even in leukemic organs that were grossly larger than normal organs. Hence, routine screening of leukemic tissue by SSCP and sequencing may result in a highly significant underestimation of the incidence ofp53mutations. The widely reported discrepancies between the loss of tumor suppressor genes (e.g., p16INK4) in human tumors compared with the incidence of loss in cell lines established from the tumors may, in part, result from similar detection difficulties. © 1995 Wiley‐Liss, Inc.