P53 MUTATIONAL STATUS AND SURVIVAL OF HUMAN BREAST-CANCER MCF-7 CELL VARIANTS AFTER EXPOSURE TO X-RAYS OR FISSION NEUTRONS
P53 MUTATIONAL STATUS AND SURVIVAL OF HUMAN BREAST-CANCER MCF-7 CELL VARIANTS AFTER EXPOSURE TO X-RAYS OR FISSION NEUTRONS
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DOI：
10.2307/3579133
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发表时间：
1995-06-01
影响因子：
3.4
通讯作者：
MELTZER, SJ
中科院分区：
文献类型：
--
作者：
BALCERKUBICZEK, EK;YIN, J;MELTZER, SJ
我们评估了X射线或裂变中子的细胞毒性以及照射和未照射的人乳腺癌MCF-7细胞活跃生长培养物中p53肿瘤抑制基因的状态。在相同的实验中研究了一个亲本或野生型（WT）和另一个对阿霉素（ADR（R））具有抗性。我们发现，相对于MCF-7 WT细胞，MCF-7 ADR（R）细胞表现出对X射线的小但显著的抵抗力，但对裂变中子没有抵抗力。对MCF-7 WT或ADR（R）细胞的混合多克隆或单克隆群体进行单链构象多态性分析，随后进行DNA测序和p53蛋白特异性抗体免疫组织化学染色，证实野生型细胞具有两个正常的p53基因拷贝。我们在阿霉素耐药细胞中发现了p53基因杂合性缺失和p53基因剩余等位基因的点突变。该突变是外显子5上游边界上的剪接受体位点改变，并导致p53蛋白过表达。在X射线或裂变中子照射后存活的MCF-7 WT或ADR（R）细胞中未观察到新的p53突变。我们的研究结果表明，突变的p53等位基因影响细胞毒性的DNA损伤的X射线的结果，但不从中子。(C)1995年，辐射研究学会
We assessed cytotoxicity of X rays or fission neutrons and the status of the p53 tumor suppressor gene in irradiated and unirradiated actively growing cultures of human breast cancer MCF-7 cells. One parental or wild-type (WT) and the other resistant to adriamycin (ADR(R)) were studied within the same experiment. We found that, relative to MCF-7 WT cells, MCF-7 ADR(R) cells exhibited a small but significant resistance to X rays, but not to fission neutrons. Single-strand conformation polymorphism analysis followed by DNA sequencing and immunohistochemical staining with a p53 protein-specific antibody performed on pooled polyclonal or monoclonal populations of MCF-7 WT or ADR(R) cells confirmed that wild-type cells have two normal copies of the p53 gene. We discovered p53 loss of heterozygosity and a point mutation in the remaining allele of the p53 gene in adriamycin-resistant cells. This mutation is a splice acceptor site change on the upstream border of exon 5 and results in p53 protein overexpression. No new p53 mutations were observed in MCF-7 WT or ADR(R) cells surviving either X or fission-neutron irradiations. Our results suggest that the mutant p53 allele affects cytotoxic outcomes of DNA damage from X rays but not from neutrons. (C) 1995 by Radiation Research Society