Structural Optimization of Celecoxib for Chemoprevention

描述(由申请人提供)：该项目旨在开发一类用于癌症预防的新型分子靶向制剂。本实验室以塞来昔布为分子起点，通过计算机模拟结构分析，开发了先导化合物OSU-02067。以前，我们证明塞来昔布阻止细胞周期、激活细胞凋亡和抑制血管生成的能力不依赖于环氧合酶-2(COX-2)的抑制，主要归因于对磷酸肌醇依赖的激酶-1(PDK-1)/Akt信号的抑制。PDK-1/Akt信号通路在癌症发生中的生物学重要性为其作为一种可行的化学预防策略提供了分子基础。因此，我们已经合成了100多个塞来昔布衍生物，用于测试PC-3人雄激素非依赖性前列腺癌细胞中PDK-1抑制活性和诱导凋亡活性。在体外和体内对一组铅化合物的测试导致了结构优化的OSU-02067的选择。OSU-02067对前列腺癌PC-3细胞的生长抑制作用低至0.5微米(塞来昔布为30微米)，对PC-3裸鼠移植瘤的生长有明显的抑制作用。更值得注意的是，它可以口服剂量，提供超过20微米的血清浓度，没有明显的毒性，与长期用于化学预防相兼容。因此，这项建议由两个具体目标组成。目的1是以OSU-02067为先导，继续开发第三代塞来昔布衍生物，增强其抑制PDK-1/AKT信号通路的活性。基于我们的工作模型，我们将专注于增强杂环系统周围的电负势，以增强其与酶口袋的相互作用。我们的目标是将抑制PDK-1/Akt信号的IC50降低到亚微米水平。目的2评价OSU-02067及其第三代类似物对不同癌细胞株的体外抗肿瘤作用。AKT激酶活性和与细胞周期停滞和凋亡相关的各种生物标志物将被检测，以了解其潜在的机制。这些发现将作为提交第二阶段拨款提案的基础，以支持我们的长期目标，即开发一类以PDK-1/Akt信号为靶点的新型药物来预防癌症。

DESCRIPTION (provided by applicant): This project is aimed at developing a novel class of molecularly targeted agents for cancer prevention. The lead compound OSU-02067 was developed in our laboratory by using celecoxib as a molecular starting point via computer modeling-based structural analysis. Previously, we demonstrated that the ability of celecoxib to arrest cell cycle, activate apoptosis, and inhibit angiogenesis is independent of cyclooxygenase-2 (COX-2) inhibition, and is primarily attributable to the inhibition of phosphoinositide-dependent kinase-1 (PDK-1)/Akt signaling. The biological importance of the PDK-1/Akt signaling pathway in carcinogenesis provides a molecular rationale to justify its inhibition as a viable strategy to chemoprevention. Consequently, we have synthesized over one hundred celecoxib derivatives for testing PDK-1 inhibitory activity and apoptosisinducing activity in PC-3 human androgen-independent prostate cancer cells. In vitro and in vivo testing of a panel of lead compounds led to the selection of a structurally optimized agent OSU-02067. OSU-02067 inhibits the proliferation of PC-3 prostate cancer cells as low as 0.5 microM (vis-a-vis 30 microM for celecoxib), and is effective in inhibiting the growth of PC-3 xenograft in nude mice. More noteworthy is that it could be orally dosed to provide serum concentrations exceeding 20 microM without demonstrable toxicity, compatible with chronic use for chemoprevention. Thus, this proposal consists of two pecific aims. Aim 1 is to use OSU-02067 as a lead to continue the development of the 3rd-generation celecoxib derivatives with enhanced activity in inhibiting PDK-1/Akt signaling. Based on our working model, we will focus on enhancing the electronegative potential surrounding the heterocyclic system to augment its interactions with the enzyme pocket. Our goal is to lower the IC50 for inhibiting PDK-1/Akt signaling to the sub-microM level. Aim 2 is to assess the in vitro antitumor effect of OSU-02067 and selected 3rd-generation analogues in different cancer cell lines. Akt kinase activities and various biomarkers pertinent to cell cycle arrest and apoptosis will be examined to understand the underlying mechanism. These findings will serve as the basis for submission of a Phase II grant proposal in support of our long-term goal to develop a novel class of agents that target PDK-1/Akt signaling for cancer prevention.