FoxM1: A molecular target in pancreatic cancer

描述(由申请人提供)： 胰腺癌(PC)是一种侵袭性恶性肿瘤，是所有癌症中预后最差的癌症之一。这在一定程度上可能是由于PC细胞在疾病的早期过程中为迁移、侵袭、血管生成和转移过程“开启开关”的能力。因此，迫切需要开发新的策略来防止胰腺肿瘤的进展。在PC中常见的EGFR和Akt信号的结构性激活被认为是激活核因子-B，核因子-B在转录上调节许多与侵袭性肿瘤生长、血管生成和侵袭有关的基因，从而导致肿瘤的进展。此外，最近的研究表明，FOXM1和Notch-1信号通路在PC中也被激活，并似乎与NF-：B串扰(请参阅我们的初步结果)。然而，FOXM1和Notch-1是如何与NF-：B串扰并调节其下游基因的，目前还不完全清楚。我们的初步数据表明，FOXM1和Notch-1信号失活导致核因子-B的下调，从而抑制细胞生长，诱导细胞凋亡，抑制肿瘤细胞的侵袭和血管生成。基于我们的初步数据，由于对FOXM1、Notch-1和NF-：B信号之间的调节和串扰缺乏分子理解，我们推测，进一步了解FOXM1、Notch-1和NF-：B之间的分子串扰，并通过一种新的药物下调它们的表达，可能是设计更好的预防胰腺肿瘤进展的策略的有效途径。我们将通过实现以下具体目标来验证我们的假设。我们将(I)确定FOXM1和Notch-1如何与NF-：B相互作用并调节其下游基因，以及FOXM1/Notch-1/NF-：B下调对PC细胞生长、凋亡、肿瘤细胞侵袭和血管生成的影响。接下来，(Ii)我们将测试我们的新方法(如使用染料木素)下调FOXM1/Notch-1信号是否不仅可以抑制侵袭和促进细胞凋亡，而且还可以增强PC细胞对EGFR酪氨酸激酶抑制剂(Erlotinib)和吉西他滨诱导的杀伤的敏感性。我们还将测试金雀异黄素的化学增敏作用是否与下调FOXM1/Notch-1/NF-：B信号有关。最后，(Iii)我们将进行体内实验(使用原位小鼠模型和转基因PC小鼠模型)，通过测试(A)染料木素诱导FOXM1/Notch-1/NF-：B信号下调是否可以使PC细胞对厄洛替尼和吉西他滨诱导的杀伤敏感，以及(B)抑制肿瘤进展是否与动物肿瘤组织中FOXM1/Notch-1/NF-：B信号的下调有关。我们的研究结果将有助于设计一种新的和有针对性的方法来预防肿瘤进展，这将与一般公共卫生高度相关，特别是对于挽救被诊断为这种致命疾病的患者的生命。公共卫生相关性：该项目致力于阐明化学预防药物可以阻止胰腺肿瘤进展的机制。因此，这笔赠款与胃肠道恶性肿瘤的预防有关。我们假设金雀异黄素下调FOXM1和Notch-1信号，进而下调核因子-B及其下游基因，从而抑制肿瘤进展。我们将使用体外分子方法和体内动物模型(包括PC的原位小鼠模型和转基因小鼠模型)，通过三个特定的目标来验证我们的假设。

DESCRIPTION (provided by applicant): Pancreatic cancer (PC) is an aggressive malignancy with one of the worst outcomes among all cancers. This could be partly due to the ability of PC cells to orchestrate in "turning-on the switch" for migration, invasion, angiogenesis and metastatic processes during the early course of the disease. Therefore, there is a dire need for the development of novel strategies by which pancreatic tumor progression could be prevented. The constitutive activation of EGFR and Akt signaling, commonly seen in PC, is known to activate NF-:B, which transcriptionally regulates many genes contributing to aggressive tumor growth, angiogenesis and invasion, resulting in tumor progression. Moreover, recent studies have shown that the FoxM1 and Notch-1 signaling pathways are also activated in PC and appear to crosstalk with NF-:B (please see our preliminary results). However, how FoxM1 and Notch-1 crosstalk with NF-:B and regulate their downstream genes are not fully understood. Our preliminary data clearly suggest that the inactivation of FoxM1 and Notch-1 signaling causes down regulation of NF-:B, which contribute to the inhibition of cell growth, induction of apoptosis and inhibition of tumor cell invasion and angiogenesis. Based on our preliminary data and because of the lack of molecular understanding of the regulation and crosstalk between FoxM1, Notch-1 and NF-:B signaling, we hypothesize that further understanding of the molecular crosstalk between FoxM1, Notch- 1 and NF-:B, and their down-regulation by a novel agent could be an effective approach for designing better strategies for the prevention of pancreatic tumor progression. We will test our hypothesis by accomplishing the following specific aims. We will (i) determine how FoxM1 and Notch-1 crosstalk with NF-:B and regulates their downstream genes, and determine the consequence of down regulation of FoxM1/Notch- 1/NF-:B in PC cell growth, apoptosis, tumor cell invasion and angiogenesis. Next, (ii) we will test whether the down regulation of FoxM1/Notch-1 signaling by our novel approach (such as the use of genistein) could not only inhibit invasion and promote apoptotic cell death but also sensitize PC cells to an EGFR-tyrosine kinase inhibitor (erlotinib) and gemcitabine-induced killing. We will also test whether the chemo-sensitizing effect of genistein is mechanistically associated with the down regulation of FoxM1/Notch-1/NF-:B signaling. Finally, (iii) we will conduct in vivo experiments (using both orthotopic mouse model and transgenic mouse models of PC) to recapitulate our in vitro findings by testing (a) whether genistein-induced down regulation of FoxM1/Notch-1/NF-:B signaling could sensitize PC cells to erlotinib and gemcitabine induced killing, and (b) whether the inhibition of tumor progression could correlate with the down regulation of FoxM1/Notch-1/NF-:B signaling in animal tumor tissues. The results of our research will aid in designing a novel and targeted approach for the prevention of tumor progression, which would be highly relevant to public health in general and especially for saving lives of patients diagnosed with this deadly disease. PUBLIC HEALTH RELEVANCE: This project is focused on elucidating the mechanism by which a chemopreventive agent could prevent pancreatic tumor progression. Therefore, this grant is related to the prevention of gastrointestinal malignancy. We hypothesize that genistein down-regulates FoxM1 and Notch-1 signaling, which in turn down-regulate NF-:B and its downstream genes, resulting in the inhibition of tumor progression. We will test our hypothesis by three specific aims using molecular approaches in vitro and by using animal models in vivo (both orthotopic mouse model and transgenic mouse models of PC).