THE USE OF TRANSCRIPTIONAL FACTORS AS TARGETS AND AGENTS FOR CHEMOPREVENTION

转录因子是基因表达的关键调节因子。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复合体被特别牵连 在调节肿瘤促进剂“佛波酯”的生物效应方面。 这个复合体的一个主要成分是c-jun癌基因。我们已经创造了 C-jun的一组显性-负性突变体能够抑制 这种癌基因的生化功能。这些突变体包括： 1)缺失氨基酸2-122的反式激活突变体， 2)三个DNA结合突变体，其中一个具有点突变 位置265，删除位置269-272，插入 265位有3个氨基酸， 3)缺失亮氨酸拉链的二聚依赖突变体， 4)一个反式激活突变体(缺失氨基酸2-122) 仅同源二聚结构域，以及 5)只含有异源二聚结构域的反式激活突变体。 我们最近已经开始测试这些突变体抑制的能力 生物功能。一种反式激活突变体已被证明能抑制Jun 和Fos癌基因转化及体外转化 促癌剂TPA的作用。对这个突变体的进一步研究已经 证明它可以抑制广泛的癌基因转化， 佛波酯在体内促癌模型系统中的作用 和一些小鼠表皮肿瘤细胞系的致瘤性。 未来的努力旨在进一步恢复…的效力和专业性 这些突变体通过创建具有更高亲和力的较小突变体来实现 二聚化和DNA结合及其在特定人肿瘤中的检测 系统，如乳腺癌和肺癌。此外，我们正在设计 可能使这些药物更具临床应用价值的传递机制 适用。最后，我们正在将这些研究扩大到包括其他 转录因子，如CREB。

Transcriptional 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 speci~cally aimed at inhibiting their biochemical and, most importantly their biologic functions. The AP-1 complex has been speci~cally 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 a panel of dominant-negative mutants of c-jun which are able to inhibit the biochemical functions of this oncogene. These mutants include: 1) a transactivation mutant with a deletion of amino acids 2-122, 2) 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, 3) a dimerization dependent mutant missing the Leucine zipper, 4) a transactivation mutant (deletion of amino acids 2-122) with a homodimerization domain only, and 5) a transactivation mutant with a heterodimerization domain only. We have recently begun to test the ability of these mutants to inhibit biologic functions. A transactivation mutant has been shown to inhibit Jun and Fos oncogene transformation in addition to the in vitro transforming effects of the tumor promoter TPA. Further work with this mutant has demonstrated that it can inhibit a wide range of oncogene transformation, the effects of phorbol ester in in vivo model systems of "tumor promotion," and tumorgenicity of some mouse epidermal tumor cell lines. Future efforts are aimed at further re~ning the potency and speci~city of these mutants by creating smaller mutants with higher af~nities for dimerization and DNA binding, and testing them in speci~c human tumor systems such as breast and lung cancers. In addition, we are designing delivery mechanisms which might make these agents more clinically applicable. Finally, we are expanding these studies to include other transcription factors such as CREB.