Anti-Promoting Effects of Triterpenes Alone or Combined with Other Phytochemicals

描述（由申请人提供）：本提案侧重于鉴定天然化合物和天然化合物的组合，其表现为卡路里限制（CR）模拟物。在其他研究中，熊果酸（UA），一种在迷迭香、苹果、浆果、紫苏（Perilla frutescens）和其他来源中发现的五环三萜化合物，以及几种其他相关的三萜类化合物已经显示出抑制TPA引起的皮肤肿瘤促进，并阻断Akt信号传导以及NF κ B信号传导。有证据表明UA也可以调节糖皮质激素受体（GR）的活性。在初步研究中，包括添加到本申请的新数据，我们发现UA对TPA处理诱导的表皮Akt、NFkB、p38 MAPK和JNK活化具有抑制作用。UA还抑制TPA诱导的表皮过度增殖。值得注意的是，UA与白藜芦醇（Res）联合给药时，似乎对这些信号通路以及TPA诱导的表皮过度增殖产生协同抑制作用。此外，UA和Res的组合在用TPA处理后显著诱导表皮AMPK的活化。初步实验表明，UA调节GR在人角质形成细胞系。另外的新数据表明，Rapa，UA，Res和UA+RES的组合抑制了毛囊隆突区域的假定干细胞的增殖。我们在P. frutescens中发现的其他五环三萜的合成/制备方面取得了重大进展。我们建议使用的两个阶段的皮肤癌发生模型，探讨化学预防特性的UA和一系列相关的五环三萜的机制。此外，我们将探索UA（或在P. frutescens中发现的更有效的三萜）与其他植物化学物质（如Res，姜黄素（Curc），6-姜烯酚（6Sho）或Rapa）组合时产生累加或可能协同的化学预防作用的可能性。我们将测试这一假设，即UA单独或与其他植物化学物质组合作为CR模拟物，通过调节生长因子信号传导，炎症信号传导和可能的其他信号传导途径来抑制启动角质形成细胞的增殖。还将测试三萜类化合物（如UA）与其他化学预防性化学品/植物化学品的组合将产生加和或协同CR模拟活性的假设。具体目标是：i）检查UA和一系列相关的五环三萜对TPA诱导的表皮信号传导途径的作用; iii）检查UA和一系列相关三萜类对角质形成细胞增殖的影响iv）检查UA与其他抗炎化学品组合是否可以实现对TPA引起的皮肤肿瘤促进的协同抑制作用。 公共卫生相关性：本提案中的研究将评估熊果酸（UA）和一系列来自P. frutescens的相关五环三萜的化学预防作用的潜在机制，这些化合物似乎具有卡路里限制（CR）模拟特性。此外，我们将探索几种不同药物与UA的组合，以获得对皮肤肿瘤促进的可能的相加或协同抑制作用。这些实验的目标将是建立一类重要的化学预防性植物化学物质（五环三萜）的机制，并确定可用于人类的化学预防剂的组合，以防止在多个组织中的上皮癌变的促进阶段。

DESCRIPTION (provided by applicant): This proposal focuses on identifying natural compounds and combinations of natural compounds that behave as calorie restriction (CR) mimetics. Ursolic acid (UA), a pentacyclic triterpene compound found in rosemary, apples, berries, Perilla frutescens (P. frutescens) and other sources, as well as several other related triterpenoids have been shown to inhibit skin tumor promotion by TPA and to block both Akt signaling as well as NFkB signaling in other studies. Evidence exists that UA may also modulate activity of the glucocorticoid receptor (GR). In preliminary studies, including new data added to this application, we have found that UA had inhibitory effects on epidermal Akt, NFkB, p38 MAPK and JNK activation induced by TPA treatment. UA also inhibited TPA-induced epidermal hyperproliferation. Notably, UA, when given in combination with resveratrol (Res), appeared to produce synergistic inhibition of these signaling pathways, as well as TPA-induced epidermal hyperproliferation. Furthermore, combinations of UA and Res dramatically induced activation of epidermal AMPK following treatment with TPA. Preliminary experiments suggest that UA modulates the GR in a human keratinocyte cell line. Additional new data demonstrates that Rapa, UA, Res and the combination of UA+RES suppress the proliferation of putative stem cells from the bulge region of hair follicles. We have made significant progress in the synthesis/preparation of additional pentacyclic triterpenes found in P. frutescens. We propose to use the well-characterized two-stage skin carcinogenesis model to explore the mechanisms that underlie the chemopreventive properties of UA and a series of related pentacyclic triterpenes. In addition, we will explore the possibility that UA (or a more potent triterpene found in P. frutescens) when combined with other phytochemicals such as Res, curcumin (Curc), 6-shogaol (6Sho) or Rapa will produce either additive or possibly synergistic chemopreventive effects. We will test the hypothesis that UA alone or in combination with other phytochemicals acts as a CR mimetic by modulating growth factor signaling, inflammatory signaling and possibly other signaling pathways to suppress proliferation of initiated keratinocytes. The hypothesis that combinations of triterpenoid compounds (such as UA) together with other chemo- preventive chemicals/phytochemicals will produce additive or synergistic CR mimetic activity will also be tested. The specific aims are: i) Examine the effect of UA and a series of related pentacyclic triterpenes on epidermal signaling pathways induced by TPA; ii) Examine the ability of UA and a series of related pentacyclic triterpenes to modulate epidermal GR function during tumor promotion; iii) Examine the effect of UA and a series of related triterpenes on keratinocyte proliferation (including bulge region KSCs) and skin inflammation in relation to their ability to inhibit skin tumor promotion by TPA; iv) Examine whether UA combined with other anti-inflammatory chemicals can achieve synergistic inhibitory effects toward skin tumor promotion by TPA. PUBLIC HEALTH RELEVANCE: Research in this proposal will evaluate the underlying mechanism(s) for the chemopreventive action of ursolic acid (UA) and a series of related pentacyclic triterpenes from P. frutescens that appear to possess calorie restriction (CR) mimetic properties. In addition, we will explore combinations of several different agents together with UA for possible additive or synergistic inhibitory effects on skin tumor promotion. The goal of these experiments will be to establish mechanisms for an important class of chemopreventive phytochemicals (pentacyclic triterpenes) and identify combinations of chemopreventive agents that could be used in humans to prevent the promotion stage of epithelial carcinogenesis in multiple tissues.