P53--DUAL GROWTH CONTROL AND DNA DAMAGE SENSITIZATION

该建议的重点是P53介导的细胞凋亡与 和DNA损伤修复，以及利用这些技术的可能性 克服胶质母细胞瘤治疗耐药性的途径。 这种肿瘤 其特征是异常恶性的性质， 突变（总体50%）和对目前所有形式的 可用的治疗。 我们发现胶质母细胞瘤细胞表达 内源性突变体P53对顺铂变得更加敏感， 野生型P53基因转移后辐射诱导的细胞凋亡， 即使在细胞的总体生长不 发生了重大变化。鉴于其潜在的临床意义， 该项目将解决：（1） 体外致敏作用的一般性 P53突变，包括显性阴性突变，以及 （2）DNA介导的细胞凋亡的作用 镇压 特别是，我们将探索一种新的方法， 使用P53沿着AP-1抑制剂的治疗敏化 调节几种DNA修复表达的转录因子 内切酶将检查P53与两种药物中的每一种的组合效应。 AP-1抑制剂，c-jun的显性负性抑制剂（突变型jun） 抑制AP-1相关的磷酸化功能 与细胞转化，和合成类维生素A，SR 11220， 能够下调AP-1活性，（3）特异性组分 影响P53介导的抑制作用的DNA修复;（4）体内 应用P53联合方法，使用皮下裸 成胶质细胞瘤的小鼠模型和Fisher大鼠颅内模型。 这些 研究旨在提供严格的临床前评价， P53介导的生长抑制和治疗敏化，以及 充分探索P53和ap-1抑制剂的联合收割机潜力， 潜在的第二代抗癌剂， 肿瘤细胞 这些研究还将深入了解 胶质母细胞瘤的耐药性和耐辐射性。

The focus of this proposal is the link between P53-mediated apoptosis and DNA damage repair, and the possibility of exploiting these pathways to overcome therapy resistance in glioblastoma. This tumor is characterized by an unusually malignant nature, by frequent P53 mutation (50% overall) and by high resistance to all forms of presently available therapy. We have found that glioblastoma cells expressing endogenous mutant P53 become much more sensitive to cisplatin and radiation-induced apoptosis following gene transfer of wild-type P53, even under conditions where overall growth of the cells is not significantly changed. In light of the potential clinical interest of this observation for glioblastoma, the project will address: (1) the generality of the sensitization effect in vitro with respect to different P53 mutations, including those which act as dominant-negatives, and with respect to different drugs, (2) The role of DNA-mediated suppression. In particular, we will explore a novel approach to therapy sensitization using P53 along with inhibitors of the AP-1 transcription factor which regulates expression of several DNA repair enzymes. The combined effects will be examined of P53 with each of two AP-1 inhibitors, a dominant-negative inhibitor of c-jun (mutant jun) that inhibits the phosphorylation-rated functions a AP-1 associated with cellular transformation, and the synthetic retinoid, SR11220, capable of down-regulating AP-1 activity, (3) The specific components of DNA repair that affect P53-mediated suppression, (4) The in vivo application of P53 combination approaches using a subcutaneous nude mouse model and a fisher rat intracranial model of glioblastoma. These studies are designed to provide a rigorous pre-clinical evaluation of P53-mediated growth suppression and therapy sensitization, and to fully explore the combine potential of P53 and ap-1 inhibitors, as potential second generation anti-cancer agents with specificity for tumor cells. The studies will also provide insight into the fundamental nature of drug and radiation resistance in glioblastoma.