Molecular Mechanisms of Prostate Cancer Chemoprevention by Apigenin

描述（由申请人提供）：本竞争性更新申请是为了继续资助研究芹菜素对前列腺癌抗癌作用的分子机制。在上一个资助期间，我们研究了芹菜素对细胞培养物、肿瘤异种移植物和转基因小鼠前列腺癌模型中各种蛋白激酶、IGF-I生长轴、B-连环蛋白和NF-β信号通路的影响。我们发现，芹菜素抑制多种信号转导途径，因此，芹菜素作用的潜在目标包括磷脂酰肌醇3-激酶（PI 3 K），蛋白激酶B/Akt，经典MAPK/ERK 1/2，和细胞周期蛋白依赖性激酶。有效抑制这些靶标的芹菜素的剂量范围与抑制信号传导和前列腺肿瘤发生的剂量范围相似，并且在人体中是生理上可达到的。在本更新申请中，我们假设I（B）激酶：IKKa/κ在介导芹菜素对多种信号转导途径的抗癌作用中充当中心枢纽。我们的假设是基于我们先前发表的发现和我们的初步数据，表明i）IKK活性在人前列腺癌中上调，其推定的前体ii）芹菜素抑制IKK活性及其磷酸化，iii）芹菜素抑制多种信号转导途径，特别是IGF-I轴、PI 3 K-Akt、NF-κ B和NF-κ B。（B和-连环蛋白途径，和iv）IKK复合物对所有这些不同的信号传导途径表现出调节作用。为了验证这一假设，我们将使用最先进的技术，包括1H NMR，X射线晶体学和先进的分子生物学程序，我们的研究将在敲入和敲除细胞培养物和转基因（TRAMP）小鼠上进行。我们提出的具体目标包括调查i）IKKa/<$在细胞转化中的作用和芹菜素的抑制活性，ii）IKKa在maspin抑制中的作用和芹菜素对其的调节，iii）IKK <$对叉头盒O3 a的活性和细胞分布的作用和芹菜素对其的调节，以及iv）IKKa/<$作为芹菜素对TRAMP小鼠体内抗癌作用的分子靶标。我们希望了解芹菜素抗癌作用的分子机制可能有助于开发有效的化学预防/治疗策略，这些策略基于更有效地靶向这些关键分子机制，并且具有更少的相关副作用。

DESCRIPTION (provided by applicant): This competitive renewal application is for continued funding to investigate the molecular mechanisms underlying the anticancer effects of apigenin on prostate cancer. During the previous funding period, we investigated the effects of apigenin on various protein kinases, the IGF-I growth axis, ¿-Catenin and NF-(B signaling pathways in cell cultures, tumor xenografts and a genetically-modified mouse model of prostate cancer. We found that apigenin inhibits multiple signal transduction pathways; consequently, potential targets of apigenin action include phosphatidylinositol 3-kinase (PI3K), protein kinase B/Akt, classical MAPK/ERK1/2, and cyclin-dependent kinases. The dose range of apigenin that effectively inhibits these targets is similar to that which suppresses signaling and prostate tumorigenesis and is physiologically attainable in humans. In this renewal application, we hypothesize that I(B kinase: IKKa/¿ acts as a central hub in mediating the anticancer effects of apigenin on multiple signal transduction pathways. Our hypothesis is based upon our previously published findings and our preliminary data showing that i) IKK activity is upregulated in human prostate cancer and its putative precursor ii) apigenin inhibits IKK activity and its phosphorylation, iii) apigenin inhibits multiple signal transduction pathways, specifically, the IGF-I axis, PI3K-Akt, NF-(B and ¿-Catenin pathways, and iv) the IKK complex exhibits regulatory effects on all of these distinct signaling pathways. To test this hypothesis, we will use state-of-the-art techniques, including 1H NMR, X-ray crystallography, and advanced molecular biology procedures, and our studies will be performed on knock-in and knockout cell cultures and on transgenic (TRAMP) mice. Our proposed specific aims include investigation of i) the role of IKKa/¿ in cell transformation and the inhibitory activity of apigenin, ii) the role of IKKa on maspin suppression and its modulation by apigenin, iii) the role of IKK¿ on activity and cellular distribution of forkhead box O3a and its modulation by apigenin, and iv) IKKa/¿ as a molecular target for the anticancer effects of apigenin in vivo on TRAMP mice. We expect that understanding the molecular mechanisms underlying the anti-cancerous effects of apigenin may be helpful in developing effective chemopreventive/therapeutic strategies based upon targeting these key molecular mechanisms more effectively and with fewer associated side-effects.