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

描述（由申请人提供）：本提案的重点是识别具有卡路里限制（CR）模拟作用的天然化合物和天然化合物的组合。熊果酸（UA）是一种五环三萜化合物，存在于迷迭香、苹果、浆果、紫苏（P. frutescens）等来源，以及其他几种相关的三萜，在其他研究中已被证明可以抑制TPA对皮肤肿瘤的促进作用，并阻断Akt信号通路和NFkB信号通路。有证据表明，UA也可能调节糖皮质激素受体（GR）的活性。在初步研究中，包括本应用中添加的新数据，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还能抑制tpa诱导的表皮增生。值得注意的是，当UA与白藜芦醇（Res）联合使用时，似乎对这些信号通路以及tpa诱导的表皮过度增生产生协同抑制作用。此外，在TPA治疗后，UA和Res联合显著诱导表皮AMPK活化。初步实验表明，UA可调节人角质形成细胞系的GR。另外的新数据表明，Rapa、UA、Res以及UA+ Res联合抑制毛囊膨出区干细胞的增殖。我们已经取得了重大进展，在合成/制备额外的五环三萜发现的紫荆。我们建议使用表征良好的两阶段皮肤癌变模型来探索UA和一系列相关的五环三萜的化学预防特性的机制。此外，我们将探索UA（或在果蔓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- shool （6Sho）或Rapa结合时产生附加或可能协同的化学预防作用的可能性。我们将验证UA单独或与其他植物化学物质联合通过调节生长因子信号、炎症信号和可能的其他信号通路来抑制初始角质形成细胞增殖的CR模拟物的假设。三萜化合物（如UA）与其他化学预防化学品/植物化学品的组合将产生添加剂或协同CR模拟活性的假设也将进行测试。具体目的是：1)研究UA及一系列相关五环三萜对TPA诱导的表皮信号通路的影响；ii)检测UA和一系列相关的五环三萜在肿瘤促进过程中调节表皮GR功能的能力；iii)检测UA和一系列相关三萜对角质细胞增殖（包括凸起区KSCs）和皮肤炎症的影响，以及它们抑制TPA促进皮肤肿瘤的能力；iv)检验UA联合其他抗炎化学物质是否能协同抑制TPA对皮肤肿瘤的促进作用。

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.