Chemoprevention by Black Raspberry of Oral Cancer Induced by Tobacco Carcinogens: Translational Studies

黑树莓对烟草致癌物诱发的口腔癌的化学预防：转化研究

• 批准号: 10087893
• 负责人: KARAM E EL-BAYOUMY
• 金额: $ 31.9万
• 依托单位: PENNSYLVANIA STATE UNIV HERSHEY MED CTR
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10087893
• 关键词: Allelic Imbalance; Anthocyanins; Antioxidants; Aromatic Polycyclic Hydrocarbons; Base Excision Repairs; Benzo(a)pyrene; Biological Assay; Carcinogens; Cells; Chemoprevention; Chemopreventive Agent; Clinical Trials; Cohort Studies; DNA Adducts; DNA Damage; DNA Repair; DNA Repair Enzymes; DNA Structure; DNA lesion; Data; Deoxyribonucleotides; Development; Dietary Intervention; Disease; Eating; Enteral; Environment; Environmental Carcinogens; Environmental Exposure; Enzymes; Epithelial; Epoxy Compounds; Etiology; Event; Excision; Exposure to; Freeze Drying; Future; Gel; Gene Mutation; Glutathione Disulfide; Glycols; Head and Neck Cancer; Heterogeneity; Human; In Vitro; Intervention; Knock-out; Literature; Loss of Heterozygosity; Malignant Epithelial Cell; Minerals; Molecular; Mus; Mutagenesis; Mutation; N' -nitrosonornicotine; NADP; Nitrosamines; Nucleotide Excision Repair; OGG1 gene; Oral; Oral Leukoplakia; Oral cavity; Oral mucous membrane structure; Oxidation-Reduction; Participant; Patients; Phase; Phenols; Powder dose form; Prevention; Prevention approach; Pyrenes; Raspberries; Reaction; Recycling; Reduced Glutathione; Ribonucleotides; Risk Factors; Role; Scheme; Smoker; Structure; Surface; TP53 gene; Time; Tissues; Tobacco; Tobacco smoke; Tobacco smoking behavior; Tobacco use; Tobacco-Associated Carcinogen; Tobacco-Related Carcinoma; Topical application; Tumor Suppressor Genes; Voice; Xenobiotic Metabolism; adduct; base; carcinogenesis; cofactor; design; disorder control; drinking; environmental tobacco smoke; foodborne; former smoker; genomic locus; high risk; insight; keratinocyte; malignant mouth neoplasm; mouse model; mouth squamous cell carcinoma; multimodality; non-smoker; novel; oxidative DNA damage; oxidative damage; preservation; prevent; public health relevance; repair enzyme; repair function; repaired; smoking cessation; targeted treatment; translational study

Project Abstract Tobacco use remains a high risk factor for oral squamous cell carcinoma (OSCC) resulting from exposure to potent tobacco carcinogens including polycyclic aromatic hydrocarbons (PAHs) such as dibenzo[a,l]pyrene (DB[a,l]P), benzo[a]pyrene (B[a]P) and tobacco-specific nitrosamines (TSNA) such as N’-nitrosonornicotine (NNN). To assess effects of these carcinogens on oral mucosa, we developed a novel OSCC mouse model using DB[a,l]P and its fjord region diol epoxide (DB[a,l]PDE). Importantly, we showed that dietary intervention with freeze-dried black raspberries (BRB) powder inhibited carcinogen-induced DNA damage, mutagenesis and carcinogenesis in the mouse oral cavity. We have also established that BRB reduce formation and/or enhance repair of bulky adducts in vitro, but, the mechanisms by which BRB reduce DNA damage remain to be fully elucidated. Considering the varied structures of DNA adducts, we will focus on BRB effects on the nucleotide excision repair (NER) and base-excision repair (BER) enzymes. Based on the abundant phenolic compounds in BRB e.g. anthocyanins, it is logical to propose that BRB help preserve the cellular redox poise, enhance redox scavenging and thus function to prevent oxidative DNA damage; our data support this proposition. In addition to their cytoprotective functions, a specific cellular reducing equivalent-NADPH-functions in reductive biosynthetic reactions including conversion of ribonucleotides to deoxyribonucleotides (dNTPs) that are essential components for DNA repair. Based on these data, we hypothesize that BRB reduce DNA damage (cf. Scheme 1, Significance) in a multimodal fashion: 1) BRB enhance NER and BER function via preservation of key substrates and cofactors i.e. dNTPs and Mg2+, while maintaining an optimal, non-oxidized environment conducive to DNA repair; 2) BRB preserve the cellular redox status via efficient scavenging of reactive species that can inhibit DNA repair enzymes thereby reducing oxidative DNA damage. The proposed mechanistic studies entail two complementary, yet independent, Specific Aims: Aim 1A will investigate the effects of BRB on repair (NER, BER) of covalent tobacco carcinogen-DNA adducts and 8-OXO-dG in primary human oral keratinocyte cells that have been transfected with these adducts using our established assay. Aim 1B will determine the capacity of BRB to prevent oxidative damage in wild-type (OGG1+/+, a component of BER enzymes) and knockout (OGG1-/-) MEF cells. Concurrent studies, applicable to both subaims, will assess BRB effect on preservation of dNTP pools and key cellular redox poise parameters in a continuum of validated cells ranging from primary human oral keratinocytes, oral leukoplakia and OSCC cells. Aim 2 will determine for the first time the effects of local BRB delivery on formation of covalent DNA adducts and 8-OXO-dG in buccal cells of healthy smokers. The results could serve as the framework for future chemopreventive trials for addicted smokers who are unable to quit as well as non- or former-smokers who are exposed to environmental carcinogens.

项目摘要 烟草的使用仍然是因暴露于 有效的烟草致癌物，包括多环芳烃（PAH），例如Dibenzo [a，l] pyrene （db [a，l] p），苯并[a] pyrene（b [a] p）和烟草特异性硝基胺（TSNA），例如n'-硝基诺诺霉素 （nnn）。为了评估这些致癌物对口服粘膜的影响，我们开发了一种新型的OSCC小鼠模型 使用db [a，l] p及其峡湾区二醇环氧（DB [a，l] PDE）。重要的是，我们表明饮食干预 用冷冻干燥的黑色覆盆子（BRB）粉末抑制致癌物诱导的DNA损伤，诱变和 小鼠口腔中的致癌作用。我们还确定，BRB减少形成和/或增强 在体外修复笨重的加合物，但是，BRB降低DNA损伤的机制尚未完全 阐明。考虑到DNA加合物的各种结构，我们将重点介绍BRB对核苷酸的影响 切除修复（NER）和基本拆卸修复（BER）酶。基于丰富的酚类化合物 在BRB中，例如花青素，提出BRB有助于保存细胞氧化还原毒物是合乎逻辑的，增强了氧化还原 清除，因此起作用以防止氧化DNA损伤；我们的数据支持此建议。此外 对于它们的细胞保护功能，一种特定的细胞减少了等效的纳德功能。 生物合成反应，包括将核糖核苷酸转化为必不可少的脱氧核糖核苷酸（DNTP） DNA修复的组件。基于这些数据，我们假设BRB减少了DNA损伤（参见。 方案1，意义）以多模式的方式：1）BRB通过保存增强NER和BER功能 关键底物和辅助因子，即DNTP和MG2+，同时保持最佳的非氧化环境 导电到DNA修复； 2）BRB通过有效清除反应性物种来保留细胞氧化还原状态 可以抑制DNA修复酶，从而减少氧化DNA损伤。提出的机械 研究需要两种完整性，但独立的特定目的：AIM 1A将研究BRB的影响 在基本人类中维修（NER，BER）的共价烟毒素DNA加合物和8-oxo-dg 使用我们已建立的测定法对这些加合物进行翻译的口服角质形成细胞。目的 1B将确定BRB的能力防止野生型氧化损伤（OGG1+/+，一个组件 BER酶）和基因敲除（OGG1 - / - ）MEF细胞。同时进行的研究，适用于两个子aims，将 评估BRB对DNTP池保存的影响和关键的细胞氧化还原固定参数 经过验证的细胞，从原代人口服角质形成细胞，口服白细胞和OSCC细胞。 AIM 2意志 首次确定局部BRB递送对共价DNA加合物形成的影响和 健康吸烟者的颊细胞中的8-氧-DG。结果可以作为未来的框架 对于无法戒烟的上瘾吸烟者以及非烟民或前吸烟者的化学预防试验 暴露于环境致癌物。