Chemical Inhibitors of CREB-mediated Gene Transcription

描述（由申请人提供）：拟定研究的目标是开发CREB（cAMP-反应元件结合蛋白）介导的基因转录的小分子抑制剂，作为潜在的抗癌药物。近年来，越来越多的证据表明CREB参与了肿瘤细胞永生化、转化和转移的调控。在一些癌症患者（例如急性白血病、前列腺癌和乳腺癌）中，CREB的表达与癌症表型相关，包括癌细胞分化、转移、复发时间和存活。这表明抑制CREB的转录活性可能是一种有前途的抗癌治疗策略。与该假设一致，在黑色素瘤和肺癌细胞系中显性负性CREB突变体的表达或在白血病细胞系中下调CREB的表达降低了癌细胞的转化表型。此外，将CRE诱饵寡核苷酸递送到人乳腺癌或前列腺癌细胞中导致体外和体内肿瘤细胞生长的显著抑制，而在正常细胞中的类似实验显示无毒性。这些结果表明，抑制CREB活性可能是一种很好的癌症治疗策略。然而，尚未开发CREB介导的小分子抑制剂用于评价抗癌活性。我们最近开发了一种新的检测方法，专门研究CREB-CBP相互作用，并发现萘酚AS-E作为CREB-CBP相互作用的小分子抑制剂在体外和细胞中。此外，我们发现这种化合物能够通过诱导许多不同癌细胞的凋亡来抑制癌细胞生长，而不管它们的p53状态如何。基于这些有希望的初步结果，我们建议进一步评估其治疗潜力并优化其抗癌活性。本论文的主要目的是：1）通过设计合成不同苯环取代的萘酚AS-E类似物，确定其作为抗癌药物和CREB-CBP相互作用抑制剂的构效关系（SAR）; 2）开发一系列新的萘酚AS-E衍生物，作为结构研究的探针; 3）探讨萘酚AS-E及其衍生物的抗癌活性是否需要CREB介导的基因转录。CREB介导的基因转录的小分子抑制剂的开发不仅将导致潜在的癌症治疗，而且还提供了一个强有力的工具，在体外和体内操纵CREB的活性，以进一步剖析其生物学功能。

DESCRIPTION (provided by applicant): The goal of the proposed research is to develop small molecule inhibitors of CREB (cAMP-response element binding protein)-mediated gene transcription as potential anticancer agents. Recently, accumulating evidence has revealed that CREB participates in the regulation of immortalization, transformation and metastasis of cancer cells. In some cancer patients (e.g. acute leukemia, prostate cancer and breast cancer), expression of CREB correlated with cancer phenotypes including cancer cell differentiation, metastasis, time to relapse and survival. This suggests that inhibiting the transcription activity of CREB could be a promising strategy for anticancer treatment. Consistent with this hypothesis, expression of a dominant-negative CREB mutant in melanoma and lung cancer cell lines or down-regulating the expression of CREB in leukemia cell lines reduced the transforming phenotypes of the cancer cells. Moreover, delivery of a CRE decoy oligonucleotide into human breast cancer or prostate cancer cells led to significant inhibition of tumor cell growth both in vitro and in vivo while similar experiments in normal cells showed no toxicity. These results indicate that pharmacologically inhibiting CREB activity could be an excellent strategy for cancer treatment. However, small molecule inhibitors of CREB-mediated have not been developed for evaluation of anticancer activity. We recently developed a novel assay to specifically look at CREB-CBP interaction and discovered naphthol AS-E as a small molecule inhibitor of CREB-CBP interaction both in vitro and in cells. Moreover, we found that this compound was able to inhibit cancer cell growth by inducing apoptosis in a number of different cancer cells irrespective of their p53 status. Based on these promising preliminary results, we propose to further evaluate its therapeutic potential and optimize its anticancer activity. The following aims will be addressed: 1) To define the structure-activity relationships (SAR) of naphthol AS-E as an anticancer agent and inhibitor of CREB-CBP interaction by designing and synthesizing analogs with different substitutions on the appendant phenyl ring; 2) To develop a novel series of naphthol AS-E derivatives with enhanced potency and aqueous solubility as probes for structural studies; 3) To investigate the hypothesis that CREB-mediated gene transcription is required for anticancer activity displayed by naphthol AS-E and its derivatives. Development of small molecule inhibitors CREB-mediated gene transcription will not only lead to potential therapeutics for cancer, but also provide a powerful tool to manipulate CREB's activity in vitro and in vivo to further dissect its biological functions.