Chemical Inhibitors of CREB-mediated Gene Transcription

描述(申请人提供)：拟议研究的目标是开发小分子抑制CREB(cAMP反应元件结合蛋白)介导的基因转录作为潜在的抗癌药物。近年来，越来越多的证据表明，CREB参与了癌细胞永生化、转化和转移的调控。在一些癌症患者(如急性白血病、前列腺癌和乳腺癌)中，CREB的表达与癌细胞分化、转移、复发时间和生存期等癌症表型相关。这表明抑制CREB的转录活性可能是一种很有前途的抗癌治疗策略。与这一假设一致的是，在黑色素瘤和肺癌细胞系中表达显性负性CREB突变体或下调白血病细胞系中CREB的表达，都会减少癌细胞的转化表型。此外，将Cre诱骗寡核苷酸输送到人乳腺癌或前列腺癌细胞中，在体外和体内都能显著抑制肿瘤细胞的生长，而在正常细胞中的类似实验表明没有毒性。这些结果表明，从药物上抑制CREB活性可能是一种很好的癌症治疗策略。然而，CREB介导的小分子抑制剂还没有被开发出来用于评估抗癌活性。我们最近开发了一种新的方法来专门研究CREB-CBP相互作用，并在体外和细胞内发现了萘酚AS-E作为CREB-CBP相互作用的小分子抑制剂。此外，我们发现这种化合物能够通过诱导许多不同的癌细胞凋亡来抑制癌细胞的生长，而与它们的P53状态无关。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。将致力于以下目标：1)通过设计和合成在附加苯环上具有不同取代基的类似物，确定萘酚AS-E作为抗癌剂和CREB-CBP相互作用抑制剂的构效关系(SAR)；2)开发一系列具有增强效力和水溶性的新型萘酚AS-E衍生物，作为结构研究的探针；3)探讨CREB介导的基因转录是萘酚AS-E及其衍生物显示抗癌活性所必需的假说。CREB介导的小分子基因转录抑制剂的开发不仅将为癌症的治疗提供潜在的途径，而且将为调控CREB的体外和体内活性以进一步剖析其生物学功能提供有力的工具。 与公共卫生相关：拟议的研究是开发CREB介导的基因转录的化学抑制剂。这些抑制剂有望成为多种癌症的潜在抗癌剂。

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. PUBLIC HEALTH RELEVANCE: The proposed research is to develop chemical inhibitors of CREB-mediated gene transcription. These inhibitors are expected to be potential candidates as anticancer agents for a variety of cancers.