Chemoprevention by black raspberry in oral cancer induced by DB[a,l]P in mice

描述(申请人提供)：口腔鳞状细胞癌(OSCC)是头颈部最常见的癌症；在美国，每年有超过45,000例和大约11,000人死于这种疾病。由于缺乏能够反映人类暴露情况的适当动物模型，口腔鳞癌的预防和控制进展受到阻碍。吸烟被认为是口腔癌发展的主要病因。一个有吸引力的动物模型是，由于长期暴露于香烟烟雾中存在的化学致癌物而导致的肿瘤，将概括人类口腔鳞癌在疾病发展过程中观察到的生化、分子和细胞变化。我们已经开发了这样一个模型，并建议将其应用于化学预防。以前的研究已经证明，含有5-10%冷冻干燥黑莓(BRB)粉的饲料能够抑制化学诱导的啮齿动物多器官部位癌症的发展，包括口腔。7，12-二甲基苯并(A)菲(DMBA)诱发仓鼠颊囊鳞状细胞癌(SCC)。然而，环境中不存在DMBA，仓鼠面颊袋模型可能不适用于人类。结果表明，烟草致癌物二苯并[a，L]芘(DB[a，L]P)可诱发口腔组织鳞癌。其代谢产物(？)-抗DB[a，L]PDE是小鼠口腔组织中一种强烈而特异的致癌物，DB[a，L]P与其二元醇环氧化物诱导的突变图谱非常相似，与稳定的共价DNA加合物的形成一致(初步结果)。用DB[a，L]P处理的小鼠口腔组织中LacI和P53基因的突变与人类口腔鳞癌中观察到的相似。此外，用LC-MS/MS检测了DB[a，L]P和(？)-抗DB[a，L]PDE对小鼠口腔组织DNA的损伤作用。初步结果表明，饲料中5%的BRB粉或0.025%的山奈酚(KF)显著抑制DB[a，L]P染毒小鼠口腔组织中DB[a，L]P-DNA加合物的形成。阿魏酸(覆盆子的成分)将通过多种机制抑制口腔肿瘤的发生，包括：抑制DNA损伤和细胞增殖，调节癌症进展的关键基因，以及诱导细胞凋亡(目标1)，并且在代表疾病不同阶段的人类口腔细胞培养中也将表现出相同的机制效应(目标2)。Aim 2将扩展我们的发现并将其转化为未来的临床研究。创新：这项应用是他第一次在高度相关的动物模型中检查BRB和相关药物对口腔鳞癌诱导的化学预防作用。此外，还将探讨BRB的化学预防机制。相关性/影响：这项使用口腔鳞状细胞癌相关动物模型的研究结果将提供急需的机械性见解，为BRB及其活性化合物未来的临床化学预防试验制定最有效的策略。

DESCRIPTION (provided by applicant): Oral squamous cell carcinoma (OSCC) is the most common cancer of the head and neck region; in the USA, over 45,000 cases and about 11,000 deaths from the disease occur annually. Progress in the prevention and control of OSCC has been hampered by the lack of appropriate animal models that would reflect human exposure. Tobacco smoking is considered a major etiological factor in the development of oral cancer. An attractive animal model would be one where tumors resulting from chronic exposure of the animal to chemical carcinogens present in cigarette smoke, would recapitulate the biochemical, molecular and cellular alterations observed in human OSCC during the development of the disease. We have developed such a model and propose to apply it to chemoprevention. Previous studies have demonstrated the ability of diets containing 5-10% freeze-dried black raspberry (BRB) powder to inhibit the development of chemically-induced cancers in multiple organ sites in rodents including the oral cavity. 7,12-Dimethylbenz(a)anthracene (DMBA) induced squamous cell carcinomas (SCC) in the hamster cheek pouch. However, DMBA is not present in the environment and the hamster cheek pouch model may not be applicable to humans. We have shown that the tobacco carcinogen, dibenzo[a,l]pyrene (DB[a,l]P) can induce SCC in oral tissues. Its metabolite, (¿)-anti- DB[a,l]PDE is a potent and specific carcinogen in oral tissues in mice and the mutational profiles induced by DB[a,l]P and its diol epoxide are very similar, consistent with the formation of stable covalent DNA adducts (Preliminary Results). Mutations in both lacI and p53 genes in oral tissues of mice treated with DB[a,l]P are similar to those observed in OSCC in humans. In addition, DNA lesions induced by DB[a,l]P and (¿)-anti- DB[a,l]PDE in the oral tissues of mice were detected by LC-MS/MS. Preliminary Results showed 5% BRB powder or 0.025% kaempferol (KF) in diets significantly inhibited DB[a,l]P-DNA adduct formation in the oral cavity of mice treated with DB[a,l]P. We hypothesize that BRB and its active components including BRB powder and its anthocyanins enriched extract, protocatechuic acid (a major metabolite of anthocyanins), KF, and ferulic acid (components of raspberries) will inhibit oral tumorigenesis and do so by multiple mechanisms including: inhibition of DNA damage and cell proliferation, modulation of genes critical to cancer progression, and induction of apoptosis (Aim 1), and will also exhibit the same mechanistic effects in human oral cell cultures representing different stages of the disease (Aim 2). Aim 2 will extend and translate our findings to future clinical studies. Innovation: This application is he first to examine the chemopreventive effects of BRB and related agents on the induction of OSCC in a highly relevant animal model. The mechanisms of chemoprevention by BRB will also be investigated. Relevance/Impact: The results of this study using a relevant animal model for OSCC will provide mechanistic insights that are urgently needed to formulate the most effective strategies for future clinical chemoprevention trials by BRB and its active compounds.