Clarification on roles of p16 and Survivin in multinuclearity and mitotic cell death of malignant glioma

阐明p16和Survivin在恶性胶质瘤多核和有丝分裂细胞死亡中的作用

基本信息

批准号：
18591591
负责人：
SUGIYAMA Kazuhiko
金额：
$ 2.45万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

Suboellularly localized (nuclear and/or cytoplasmic) survivin has various functions, and correlates with prognosis of malignant tumors. However there have been no reports about the significance of subcellularly localized survivin in high-grade astrocytomas. The aim of the our first paper was to examine the relationship between prognosis and subcellular localization of survivin in high-grade astrocytoma. Methods We immunohistochemically examined the pattern of subcellular localization of survivin expression (nuclear, cytoplasmic, or both)in 51 patients with highgrade astrocytoma (19 anaplastic astrocytomas; 32 glioblastomas). We statistically examined the relationship between survivin localization and prognosis, using multivariate analysis including other clinicopathological factors (age, sex, WHOgrade, extent of resection, MEB-1 labeling hide, and expression of p53 and epidermal growth factor receptor). Results All specimens stained positive for survivinilocalized in nucleus only (nucl … More ear-positive group), 10cases (20%); localized in cytoplasm only (cytoplasmicpositive group), 23cases (45%); simultaneous expression in nucleus and cytoplasm (nuclear-cytoplasmic group), 19cases (35%). There was no significant difference in prognosis between the nuclear-positive group and cytoplasmic-positive group (P=0.796). However, the nuclear-cytoplasmic group had significantly shorter overall survival than the nuclear-positive group and the cytoplasmic-positive group (P<0.0001). Conclusions We found that simultaneous expression of survivin in both the nucleus and cytoplasm is an important prognostic factor for high-grade astrocytoma. The present findings indicate that subcelluliar localization of survivin expression is a reliable prognostic factor for patients with this tumor.Furthermore, survivin, a regulator of chromosome segregation, is highly expressed and known to induce radioresistance in human gliomas. In second paper, we examined the effect of survivin suppression on radiosensitivity in malignant glioma cells, while focusing on centrosome aberration and chromosome instability (CIN). We suppressed survivin by small interfering RNA transktion, and examined the radiosensitivity using a clonogenic assay and a trypan blue exclusion assay in U251MG (p53mutant) and D54MG (p53 wild type) cells. To assess the CIN status, we determined the number of centrosomes using an immunolluorescence analysis, and the centromeric copy number by fluorescence in situ hybridisation. As a result, the radiosensitisation differed regarding the p53 status as U251MG cells quickly developed extreme centrosome amplification (1/4CIN) and enhanced the radiosensitivity, while centrosome amplification and radiosensitivity increased more gradually in D54MG cells. TUNED assay showed that survivin inhibition did not lead to apoptosis after irradiation. This cell death was accompanied by an increased degree of aneuploidy, suggesting mitotic cell death. Therefore, survivin inhibition may be an attractive therapeutic target to overcome the radioresistance while, in addition, proper attention to CIN (centrosome number) is considered important for improving radiosensitivity in human glioma. Less

亚细胞定位（细胞核和/或细胞质）生存素具有多种功能，并且与恶性肿瘤的预后相关。然而，目前还没有关于亚细胞定位生存素在高级别星形细胞瘤中的意义的报道。检查高级星形细胞瘤中生存素的亚细胞定位与预后之间的关系。方法我们通过免疫组织化学检查了亚细胞的模式。我们使用包括其他临床病理因素（年龄、性别、性别）在内的多变量分析，仔细检查了 51 例高级星形细胞瘤（19 例间变性星形细胞瘤；32 例胶质母细胞瘤）中生存素表达（细胞核、细胞质或两者）的定位。 WHO等级、切除范围、MEB-1标记隐藏以及p53和表皮生长因子的表达结果全部标本中survivini染色阳性，仅定位于细胞核（核阳性组），10例（20%）；仅定位于细胞质（细胞质阳性组），23例（45%）；细胞质组）19例（35%），核阳性组与细胞质阳性组预后无显着差异。细胞核阳性组和细胞质阳性组的总生存期显着缩短（P=0.796）。细胞质是高级别星形细胞瘤的重要预后因素目前的研究结果表明，生存素表达的亚细胞定位是此类患者的可靠预后因素。此外，生存素（染色体分离的调节因子）在人类神经胶质瘤中高表达，并且已知会诱导放射抗性。在第二篇论文中，我们研究了生存素抑制对恶性神经胶质瘤细胞放射敏感性的影响，同时重点关注中心体畸变和染色体不稳定性。 (CIN)。我们通过小干扰 RNA 转运抑制了存活蛋白，并使用克隆形成试验和台盼病毒检查了放射敏感性。在 U251MG（p53 突变型）和 D54MG（p53 野生型）细胞中进行蓝色排除测定为了评估 CIN 状态，我们使用免疫荧光分析确定了中心体的数量，并通过荧光原位杂交确定了中心体的拷贝数。由于 U251MG 细胞迅速发展出极端中心体扩增 (1/4CIN) 并增强了 p53 状态，因此放射增敏作用有所不同。放射敏感性，而 D54MG 细胞的中心体扩增和放射敏感性逐渐增加，表明生存素抑制不会导致辐射后细胞凋亡，这种细胞死亡伴随着非整倍性程度的增加，因此，生存素抑制可能导致细胞死亡。成为克服放射抗性的一个有吸引力的治疗靶点，此外，适当关注 CIN（中心体数）被认为对于改善放射抗性很重要人类神经胶质瘤的放射敏感性较低。