Lung Cancer Chemoprevention through LC-1

描述(由申请人提供)： 部分由烟草烟雾或环境毒物介导的慢性炎症在肺癌的发生和发展中起着重要作用。肺癌的进展与转录因子核因子-β的活性增加有关，核因子-β是执行炎症反应的主要因素。此外，在肺癌的早期阶段，由于组蛋白脱乙酰酶如HDAC1和组蛋白甲基转移酶如EZH2的表达增加，可观察到表观遗传程序的改变。因此，一种能够降低这些蛋白的表达和/或活性的药物可能成为肺癌的化学预防药物。在我们寻找具有抗核因子-βB活性的药物的过程中，我们确定了菊内酯是一种抑制核因子-βB并使癌细胞对化疗敏感的新型药物。我们开发了一种名为LC-1的这种化合物的水溶性类似物，它与巴豆内酯一样有效，但显示出更好的生物利用度和药代动力学。LC-1不仅能抑制NF-β，还能降低HDAC1及其相关蛋白CtBP1和EZH2的水平。HDAC1、CtBP1和EZH2组成转录抑制复合体，介导肺癌中p14ARF和死亡相关蛋白激酶-1(DAPK1)等抑癌基因的表观遗传沉默。此外，LC-1还诱导了细胞周期蛋白激酶抑制因子p21和抑癌/促凋亡基因TAp73的表达，该基因由于启动子甲基化或缺失而在肺癌中低水平表达。此外，LC-1在体外和异种移植模型中均能抑制肺癌细胞的生长。LC-1还可降低烟草致癌物诱导的未转化肺上皮细胞中核因子？B和细胞周期蛋白D1的表达。假设：LC-1通过抑制两种主要致癌刺激--炎症和肿瘤抑制因子的表观遗传沉默，成为肺癌的有效化学预防药物。目的：检测LC-1对环境毒物乌拉坦(Urethane，一种环境毒物)诱导的FVB/N小鼠肺癌的化学预防作用，该作用依赖于肺上皮细胞的炎症反应和核因子-β活化。目的研究LC-1对烟草致癌物4-甲基亚硝胺-1-3-吡啶-1-丁酮和苯并(A)芘诱发的A/J小鼠肺癌的影响。通过检测未经处理和LC-1处理的动物肺组织中活化的核因子-β以及EZH2、HDAC1、CtBP1、ARF和DAPK1的表达水平，我们将探讨这些蛋白是否可以作为肺癌化学预防的生物标志物。由于LC-1不久将作为白血病的治疗药物在临床上进行测试，拟议的研究将使其能够迅速转化为临床，特别是对于现在或以前吸烟者。

DESCRIPTION (provided by applicant): Chronic inflammation, mediated partly by tobacco smoke or environmental toxicants, plays a significant role in initiation and progression of lung cancer. Lung cancer progression is associated with increased activity of the transcription factor NF-?B, which is a major factor executing inflammatory response. Additionally, altered epigenetic program, as a consequence of elevated expression of histone deacetylases such as HDAC1 and histone methyl transferases such as EZH2, is observed in early stages of lung cancer. Therefore, an agent that can reduce the expression and/or activity of these proteins may serve as chemopreventive agent for lung cancer. During our search for agents with anti-NF-?B activity, we identified parthenolide as a novel agent that inhibits NF-?B and sensitizes cancer cells to chemotherapy. We developed a water-soluble analogue of this compound called LC-1, which is as potent as parthenolide but shows improved bioavailability and pharmacokinetics. LC-1 not only inhibited NF-?B but also reduced the levels of HDAC1 and its associated proteins CtBP1 and EZH2. HDAC1, CtBP1 and EZH2 constitute a transcription repression complex that mediates epigenetic silencing of tumor suppressor genes such as p14ARF and death-associated protein kinase-1 (DAPK1) in lung cancer. Additionally, LC-1 induced the expression of cell cycle kinase inhibitor p21 and the tumor suppressor/pro-apoptotic gene TAp73, which is expressed at low levels in lung cancer due to promoter methylation or deletion. Furthermore, LC-1 inhibited the growth of lung cancer cells in vitro and in xenograft models. LC-1 also reduced tobacco carcinogen-induced activation of NF-?B and cyclin D1 expression in non-transformed lung epithelial cells. Hypothesis: LC-1 serves as a potent chemopreventive agent for lung cancer by inhibiting two major carcinogenic stimuli- inflammations and epigenetic silencing of tumor suppressors. Specific aims: Aim I will test the chemopreventive activity of LC-1 in Urethane (an environmental toxicant)- induced lung cancer in FVB/N mice, which is critically dependent on inflammation and NF-?B activation in lung epithelial cells. Aim 2 will test the effect of LC-1 on tobacco carcinogens 4-(methylnitrosamine)-1-3-Pyridyl-1- butanone- and benzo(a)pyrene-induced lung cancer in A/J mice, which shows extensive epigenetic silencing of tumor suppressor genes. By measuring the levels of activated NF-?B, and the expression levels of EZH2, HDAC1, CtBP1, ARF, and DAPK1 in lung tissues of untreated and LC-1 treated animals, we will investigate whether these proteins serve as biomarkers for lung cancer chemoprevention. As LC-1 will soon be tested in clinic as a treatment for leukemia, the proposed studies will enable speedy translation to clinic, particularly for current or ex-smokers.