Pykett M J, Azzam E, Dahlberg W, Little J B
Department of Cancer Biology, School of Public Health, Harvard University, Boston, MA 02115, USA.
Int J Oncol. 1998 Aug;13(2):213-6. doi: 10.3892/ijo.13.2.213.
Gliomas are part of a subset of tumors in which overexpression of p53 protein in the absence of p53 gene mutation has been described. We have utilized a series of glioma cell lines to study the effects of ionizing radiation on the regulation of p53, p21, mdm2 and Rb proteins. The induction of p53 protein in glioma cell lines that overexpress wild-type p53 differs from normal control cells and glioma cell lines containing mutant p53. Alterations in the accumulation of p53 and p21 proteins are associated with diminished Rb hypophosphorylation. Gliomas that overexpress wild-type p53 also express high levels of mdm2 protein and exhibit a radiosensitivity that is intermediate between normal cells and cells with mutant p53. These findings suggest that, at least in certain glioma cell lines that over-express p53 which is wild-type in sequence, the function of p53 protein is abnormal.
胶质瘤是一类肿瘤的一部分，在这类肿瘤中，已发现存在p53基因无突变但p53蛋白过表达的情况。我们利用一系列胶质瘤细胞系来研究电离辐射对p53、p21、mdm2和Rb蛋白调控的影响。在过表达野生型p53的胶质瘤细胞系中，p53蛋白的诱导情况不同于正常对照细胞和含有突变型p53的胶质瘤细胞系。p53和p21蛋白积累的改变与Rb蛋白低磷酸化的减少有关。过表达野生型p53的胶质瘤也表达高水平的mdm2蛋白，并且表现出介于正常细胞和具有突变型p53细胞之间的放射敏感性。这些发现表明，至少在某些过表达序列为野生型p53的胶质瘤细胞系中，p53蛋白的功能是异常的。
