THE USE OF TRANSCRIPTIONAL FACTORS AS TARGETS AND AGENTS FOR CHEMOPREVENTION

转录因子是基因表达的关键调控因子。它是 很明显，这些因素控制着许多基因的表达，因此， 调节诸如“肿瘤促进剂”之类的生物效应。这个 本项目的目的是设计转录因子的突变体。 特别是为了抑制他们的生化反应，最重要的是 它们的生物功能。 AP-1复合体已经被明确地牵涉到介导生物 肿瘤促进剂“佛波酯”的作用。这其中的一个主要组成部分 复合体是c-jun癌基因。我们已经创建并测试了一系列 C-jun的显性-负性突变体能够抑制 这种癌基因的生化功能。一个变态突变体，带有 N-末端氨基酸2-122的缺失已被证明抑制AP-1 反式激活和c-jun转化。此外，这个突变体还具有 已被证明通过广泛的癌基因抑制细胞转化 包括c-fos、c-raf、ras、mos和myc。此外，稳定表达 小鼠表皮细胞中的这种突变蛋白可以阻断佛波酯 诱导肿瘤促进作用。这种突变体的作用机制是 证明是与其他AP-1的异二聚化和中和 复杂的组件，如c-fos。 我们最新的努力旨在进一步提炼效力和 通过创建更小的突变体来获得这些突变体的特异性 二聚化和DNA结合的亲和力及其在特定条件下的测试 人类肿瘤系统，如乳腺癌和肺癌。我们现在已经创建了一个 一系列含有较大N端缺失的c-jun突变体 只含有亮氨酸拉链的小肽(二聚结构域)。 此外，包括一个点突变在内的三个DNA结合突变体 在第265号位置，删除了第269-272号位置，插入了一个 在第265位产生了3个氨基酸。所有这些突变体 已被证明具有显性-负性表型。 未来的努力旨在设计交付机制，这可能会使 这些药物在临床上更适用。将进行体内测试 在模型系统中。最后，我们将扩大这些研究的范围，将其他 在人类癌症发生中起关键作用的转录因子 例如CREB。

Transcription factors are critical regulators of gene expression. It is clear that these factors control the expression of many genes and, as such, mediate the biologic effects of agents such as "tumor promoters." The purpose of this project is to design mutants of transcription factors specifically aimed at inhibiting their biochemical and most importantly their biologic functions. The AP-1 complex has been specifically implicated in mediating the biologic effects of the tumor promoters "phorbol esters." A major component of this complex is the c-jun oncogene. We have created and tested a series of dominant-negative mutants of c-jun which are able to inhibit the biochemical functions of this oncogene. A transactivation mutant with a deletion of the N-terminal amino acids 2-122 has been shown to inhibit AP-1 transactivation and c-jun transformation. In addition, this mutant has been shown to inhibit cellular transformation by a wide range of oncogenes including c-fos, c-raf, ras, mos, and myc. Further, stable expression of this mutant protein in mouse epidermal cells can block phorbol ester induced tumor promotion. The mechanism of action of this mutant has been demonstrated to be heterodimerization with and neutralization of other AP-1 complex components such as c-fos. Our most recent efforts are aimed at furthering refining the potency and specificity of these mutants by creating smaller mutants with higher affinities for dimerization and DNA binding and testing them in specific human tumor systems such as breast and lung cancers. We have now created a series of c-jun mutants containing larger N-terminal deletions producing small peptides containing only the leucine zipper (dimerization domain). In addition, three DNA binding mutants including one with a point mutation at position 265, a deletion at positions 269-272, and one with an insertion of 3 amino acids at position 265 have been produced. All of these mutants have been demonstrated to have a dominant-negative phenotype. Future efforts are aimed at designing delivery mechanisms which might make these agents more clinically applicable. In vivo testing will be performed in model systems. Finally, we will expand these studies to include other transcription factors which play critical roles in human carcinogenesis such as CREB.