14-3-3 IMPLICATIONS IN TOPOISOMERASE II PHARMACOLOGY

描述：DNA拓扑异构酶II（topo II）是一种普遍存在的核酶 它催化了各种三级结构的相互转化， DNA. 这种酶对细胞增殖是绝对必要的，因为它 在有丝分裂之前十链体物理地互锁DNA。 Topo II也是一款 广泛使用的一类化疗药物的临床相关靶点 毒品 topo II生物化学的研究揭示了几种机制， 哪些肿瘤细胞响应于或逃避所述细胞因子的细胞毒性作用， Topo-II导向的抗癌药物。 在过去的三年里，校长 研究人员一直在发展一种假设，即拓扑异构酶II的活性可以 由蛋白质-蛋白质相互作用和这些蛋白质的调节介导 也可能影响肿瘤细胞对Topo II毒物的反应。 其他人已经 描述了来自酵母和果蝇的拓扑异构酶II相互作用蛋白（TIP）， 是染色体分离所必需的 一种人类的 酵母TIP，Sgs 1，很可能是致病基因，改变了， 布鲁姆综合征。 因此，拓扑异构酶II蛋白相互作用的研究 揭示了这种酶在人类肿瘤形成中未被重视的作用。 主要研究者的研究建议重点关注以下方面的作用： 拓扑异构酶II蛋白相互作用的细胞毒性作用的拓扑异构酶II-定向 毒品 为了达到这一目的，已经建立了人HeLa细胞cDNA表达文库， 筛选与主要α-受体的C-末端相互作用的蛋白质， 人类拓扑二型。 其中一个tip已被确定为 人14-3-3蛋白同种型。 14-3-3蛋白，一种异常高的 在植物、真菌和哺乳动物中发现的保守蛋白质家族， 在许多原癌和致癌细胞中反复涉及 信号通路 14-3-3蛋白似乎也隔离了凋亡的细胞。 死亡激动剂Bad在IL-3保护T细胞中的作用。 校长 因此，研究者建议1）测试14-3-3/topo II是否 相互作用是真实的，发生在完整的细胞和2）调查 这种相互作用的生物化学和药理学后果， 肿瘤细胞过度表达14-3-3蛋白。 高水平的保护 14-3-3蛋白，它们在细胞生长信号中的意义， 凋亡，表明14-3-3/topo II相互作用可能是 具有生物学意义。 最重要的是，这些相互作用也可能 调节肿瘤细胞对topo-II导向的抗肿瘤药物的敏感性。

DESCRIPTION: DNA topoisomerase II (topo II) is a ubiquitous nuclear enzyme which catalyzes the interconversion of the various tertiary structures of DNA. This enzyme is absolutely essential to cellular proliferation since it decatenates physically interlocked DNA prior to mitosis. Topo II is also a clinically relevant target for a widely useful class of chemotherapeutic drugs. The study of topo II biochemistry has revealed several mechanisms by which tumor cells respond to, or evade, the cytotoxic effects of the topo-II-directed anticancer drugs. In the past three years, the Principal Investigator has been developing the hypothesis that topo II activity can be mediated by protein-protein interactions and modulation of these proteins may also affect tumor cell response to topo II poisons. Others have described topo II interactive proteins (TIPs) from yeast and Drosophila that are necessary for faithful chromosomal segregation. A human homolog of the yeast TIP, Sgs1, is likely to be the causative gene that is altered in Bloom's syndrome. Therefore, study of topo II protein interactions has revealed unappreciated roles for the enzyme in human neoplasia. The Principal Investigator's studies propose to focus instead on the role of topo II protein interactions in the cytotoxic action of topo-II-directed drugs. Toward this aim, a human HeLa cell cDNA expression library has been screened for proteins that interact with the C-terminus of the major alpha form of human topo II. One of the TIPs has been identified as the epsilon isoform of human 14-3-3 protein. 14-3-3 proteins, an unusually highly conserved protein family found in plants, fungi, and mammals, have been implicated repeatedly in numerous protooncogenic and oncogenic cellular signaling pathways. 14-3-3 proteins also appear to sequester the apoptotic death agonist, Bad, in IL-3 protection of T cells. The Principal Investigator therefore proposes 1) to test whether the 14-3-3/topo II interaction is authentic and occurs in intact cells and 2) to investigate the biochemical and pharmacological consequences of this interaction in tumor cells overexpressing 14-3-3 protein. The high level of conservation of 14-3-3 proteins, their implication in cellular growth signaling and now apoptosis, suggest that 14-3-3/topo II interactions are likely to be biologically significant. Most importantly, these interactions may also modulate tumor cell susceptibility to topo-II-directed antitumor drugs.