Targeting multiple skin cancer pathways using citrus auraptene and ATRA

描述（由申请人提供）：对非黑色素瘤皮肤癌（NMSC）的安全、长期预防性治疗的需求日益增加，NMSC对高风险人群（如不断增长的免疫功能低下的实体器官移植患者、HIV患者和老年非西班牙裔高加索人）构成特别威胁。我们已经证明，充分表征的化学预防性维生素A代谢物全反式维甲酸（ATRA）与生物活性膳食剂金萝卜素（AUR）的组合可以协同或超加和地抑制小鼠异种移植模型中的皮肤鳞状细胞癌（SCC）肿瘤生长。我们研究的长期目标是开发有效的上皮癌化学预防治疗方法。为了实现这一目标，本项目的主要目的是更好地了解ATRA和AUR对皮肤SCC发展的影响。我们的总体假设是，由于ATRA抑制Stat 3信号传导的能力和AUR抑制NF-：B途径和其他途径的能力，ATRA + AUR组合比单独的任一种药物更有效。Stat 3是控制细胞增殖和存活的转录因子，并且在细胞凋亡、增殖、运动性和血管生成的调节中是重要的，这些都是恶性肿瘤的标志。我们的实验室和其他实验室已经表明，Stat 3活性在几种恶性细胞类型中是组成性的，并且是皮肤SCC中启动、促进和进展为更恶性表型所必需的。NF-：B是一种生存信号转录因子，也参与许多癌症（包括SCC）的恶性表型。我们的初步结果表明，ATRA+AUR组合抑制来自人皮肤SCC细胞系SRB 12-p9（P9 WT）的肿瘤在严重联合免疫缺陷（SCID）小鼠原位肿瘤发生模型中的生长。我们将首先检查更宽剂量范围的ATRA 1 AUR对SCID小鼠肿瘤体积的影响。我们将比较AUR治疗在Stat 3的药理学抑制（ATRA治疗）与Stat 3的遗传抑制（Stat 3的显性负作用形式的稳定表达; S3 DN细胞）的背景下的作用。将详细分析肿瘤的恶性性质以及Stat 3和NF-：B通路的抑制。我们将通过在P9 WT SCC细胞中单独和联合基因阻断Stat 3途径（S3 DN细胞）和NF-：B途径（shRNA介导的NF-：B敲低）来进一步验证我们的假设。将确定所得途径抑制细胞的致瘤特性。 公共卫生相关性：该项目的目标是提供证据，证明全反式视黄酸（一种维生素A衍生物）与柑橘衍生化合物金萝卜素的组合将提供预防非黑色素瘤皮肤癌发展的增强效果。该项目与人类健康的相关性在于，非黑色素瘤皮肤癌每年折磨着100多万美国人，并可能导致使人衰弱的疾病甚至死亡。此外，某些人群，如实体器官移植患者（截至2006年> 173，000），HIV患者和其他免疫功能低下的个体患这些类型癌症的风险大大增加。因此，需要增加有效性同时限制毒性的新型预防策略。

DESCRIPTION (provided by applicant): There is an increasing need for safe, long-term preventive treatments for non-melanoma skin cancer (NMSC), which is a particular threat to high risk groups such as the growing populations of immunocompromised solid organ transplant patients, HIV patients, and elderly non-Hispanic Caucasians. We have shown that a combination of the well-characterized chemopreventive vitamin A metabolite, all-trans retinoic acid (ATRA), with the bioactive dietary agent auraptene (AUR), can synergistically or supra-additively suppress skin squamous cell carcinoma (SCC) tumor growth in a mouse xenograft model. A long-term goal of our research is to develop effective chemopreventive treatments for epithelial cancers. In keeping with this goal, the primary aim of this project is to gain a better understanding of the effects of ATRA, and AUR on the development of skin SCC. Our overall hypothesis is that the ATRA + AUR combination is more effective than either agent alone due to the ability of ATRA to suppress Stat3 signaling, and AUR to suppress the NF-:B pathway and other pathways. Stat3 is a transcription factor that controls cell proliferation and survival, and is important in the regulation of apoptosis, proliferation, motility, and angiogenesis, all hallmarks of malignancy. Our laboratories and others have shown that Stat3 activity is constitutive in several malignant cell types and is required for initiation, promotion and progression to a more malignant phenotype in skin SCC. NF-:B is a survival signaling transcription factor also involved in the malignant phenotype of many cancers, including SCCs. Our preliminary results show that the ATRA+AUR combination suppresses the growth of tumors derived from the human skin SCC cell line SRB12-p9 (P9 WT), in the severe combined immunodeficient (SCID) mouse orthotopic tumorigenesis model. We will first examine the effects of a wider range of doses of ATRA 1 AUR against tumor volume in SCID mice. We will compare the effects of AUR treatment in the context of pharmacological suppression of Stat3 (ATRA treatment) to genetic suppression of Stat3, (stable expression of a dominant negative acting form of Stat3; S3DN cells). Tumors will be analyzed in detail for malignant properties and for suppression of Stat3 and NF-:B pathways. We will further verify our hypothesis by genetically blocking the Stat3 pathway (S3DN cells) and the NF-:B pathway (shRNA mediated knockdown of NF-:B), alone and in combination, in the P9WT SCC cells. The tumorigenic properties of the resulting pathway suppressed cells will be determined. PUBLIC HEALTH RELEVANCE: The goal of this project is to provide evidence that the combination of all-trans retinoic acid, a vitamin A derivative, with a citrus derived compound, auraptene, will provide an enhanced effect to prevent non- melanoma skin cancer development. The relevance of this project to human health is that non-melanoma skin cancer afflicts more than one million Americans every year, and can result in debilitating disease and even death. Furthermore, certain populations, such as solid organ transplant patients (> 173,000 as of 2006), HIV patients, and other immunocompromised individuals are at a greatly increased risk for these types of cancers. Novel prevention strategies that increase effectiveness while limiting toxicity would therefore be desirable.