Mechanisms of tumor suppressor gene reactivation in colon cancer by berries

浆果重新激活结肠癌抑癌基因的机制

• 批准号: 8058719
• 负责人: Li-Shu Wang
• 金额: $ 28.18万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-08 至 2015-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8058719
• 关键词: Adenomatous Polyposis Coli; Animal Model; Animals; Anthocyanins; Apoptosis; Azoxymethane; Berry; Birds; Cancer Etiology; Cancer Patient; Carcinogenesis Inhibition; Carcinogens; Cell Culture System; Cell Proliferation; Cells; Cessation of life; Chemoprevention; Chemopreventive Agent; Clinical; Colon; Colon Carcinoma; Colonic Adenoma; Colonic Neoplasms; Color; Colorectal Cancer; Colorectal Neoplasms; Consumption; DNA Methyltransferase; DNA Modification Methylases; DNA Nucleotidylexotransferase; Development; Diagnosis; Diet; Disease; Distant Metastasis; Drug Kinetics; E-Cadherin; ENG gene; Epidemiologic Studies; Esophageal; Fractionation; Freeze Drying; Gene Expression; Gene Silencing; Genes; Goals; Grant; Human; Human Development; Hypermethylation; In Situ Nick-End Labeling; Intervention; Intervention Trial; Intestines; Knock-out; Label; Laboratories; Malignant Neoplasms; Mediating; Methylation; Modeling; Mus; Oral; Pathway interactions; Patients; Persons; Polyps; Powder dose form; Prevention; Prevention strategy; Raspberries; Rattus; Rectal Polyp; Rectal Suppositories; Role; Serum; Small Intestines; Specimen; Staining method; Stains; Testing; Tissues; Tumor Suppressor Genes; Tumor Tissue; United States; Water; Woman; adenoma; angiogenesis; base; c-myc Genes; cancer cell; cancer prevention; carcinogenesis; colorectal cancer prevention; demethylation; fruits and vegetables; men; mortality; neoplastic cell; novel; protective effect; protein expression; public health relevance; trend; tumor; tumorigenesis; uptake; urinary

DESCRIPTION (provided by applicant): Although mortality rates from colorectal cancer have declined in both men and women over the past two decades, the 5-year survival from this disease is 64% and continues to decline to 57% at 10 years after diagnosis. For persons with distant metastases at diagnosis, the 5-year survival is only 10%. Therefore, the prevention of colon cancer remains an important goal and chemoprevention is a viable approach to achieve this goal. Our laboratory has been evaluating the use of freeze-dried berries, mainly black raspberries (BRBs), for the prevention of colon cancer in animals and in humans. The addition of BRB powder to the diet inhibited the development of colonic adenomas and carcinomas in azoxymethane (AOM)-treated rats, and of spontaneous adenomas in the intestine of ApcMin/+ mice. Two pilot intervention trials have been conducted in humans: one in patients with sporadic colorectal cancer and the other in patients with familial adenomatous polyposis (FAP). Our results suggest that short-term treatment of sporadic colorectal cancer patients with oral BRB powder (20g/3x/day) significantly reduced cell proliferation rates and produced a positive trend for changes in apoptosis, angiogenesis, and in genes associated with the Wnt pathway in colorectal tumors. Our FAP trial indicated that nine month treatment of FAP patients with BRB powder administered both orally (20g/3x/day) and in the form of rectal suppositories caused a 53% regression rate of rectal polyps. These results suggest that berries have potential for prevention of colorectal cancer in humans. Using bio-directed fractionation, we and our collaborators found that the anthocyanins in BRBs are important for their chemopreventive effects. Recent preliminary studies suggest that the colorectal cancer inhibitory effect of BRBs may be due, at least in part, to their ability to inhibit DNA methyltransferase 1 (DNMT1) protein expression and total DNMT activity in human colon tumor cells, which led to demethylation and reactivation of hypermethylation-silenced tumor suppressor genes such as p16. Short-term BRB intervention in colorectal cancer patients resulted in the demethylation of p16 and re-expression of the gene in aberrant crypts of colonic tumor tissues. We propose therefore to determine if demethylation and reactivation of hypermethylation- silenced genes by BRB anthocyanins in human colon cancer cells and in ApcMin/+ mice is associated with inhibition of tumorigenesis (Specific Aim 1) and the role of DNMT1 in BRB anthocyanin-induced demethylation of tumor suppressor genes (Specific Aim 2). We will also determine if BRBs influence the methylation state of hypermethylation-silenced tumor suppressor genes in specimens obtained from the two human BRB intervention trials, and its association with reduced cell proliferation and polyp regression (Specific Aim 3). Finally, we will conduct a pharmacokinetic study to determine the uptake of anthocyanins into human colon cells, and intestinal tissue and serum, as well as urinary levels of anthocyanins and their metabolites when administered at different concentrations in the diet to ApcMin/+ mice (Specific Aim 4). Ultimately, we plan to evaluate anthocyanins for prevention of colorectal cancer in humans. PUBLIC HEALTH RELEVANCE: Colon cancer is the third most prevalent cancer, and the third leading cause of cancer death in the United States. Our laboratory is developing strategies for the prevention of colon cancer using freeze-dried berries. We now propose to evaluate the anthocyanins in berries for their ability to demethylate and reactivate tumor suppressor genes in colon cancer.

描述（由申请人提供）：尽管在过去二十年中，男性和女性结直肠癌的死亡率均有所下降，但该疾病的 5 年生存率为 64%，并在诊断后 10 年继续下降至 57%。对于诊断时已发生远处转移的患者，5 年生存率仅为 10%。因此，预防结肠癌仍然是一个重要目标，而化学预防是实现这一目标的可行方法。我们的实验室一直在评估冻干浆果（主要是黑树莓 (BRB)）在动物和人类中预防结肠癌的用途。在饮食中添加 BRB 粉末可抑制氧化偶氮甲烷 (AOM) 处理的大鼠结肠腺瘤和癌的发展，以及 ApcMin/+ 小鼠肠道自发性腺瘤的发展。两项试点干预试验已在人类身上进行：一项针对散发性结直肠癌患者，另一项针对家族性腺瘤性息肉病 (FAP) 患者。我们的结果表明，口服 BRB 粉末（20g/3x/天）对散发性结直肠癌患者进行短期治疗显着降低了细胞增殖率，并对结直肠肿瘤中细胞凋亡、血管生成和与 Wnt 通路相关的基因的变化产生了积极的趋势。我们的 FAP 试验表明，对 FAP 患者进行 9 个月的口服 BRB 粉末（20g/3x/天）和直肠栓剂治疗，直肠息肉消退率达到 53%。这些结果表明浆果具有预防人类结直肠癌的潜力。通过生物定向分馏，我们和我们的合作者发现 BRB 中的花青素对其化学预防作用很重要。最近的初步研究表明，BRB 的结直肠癌抑制作用可能至少部分归因于它们抑制人类结肠肿瘤细胞中 DNA 甲基转移酶 1 (DNMT1) 蛋白表达和总 DNMT 活性的能力，从而导致高甲基化沉默的肿瘤抑制基因（如 p16）去甲基化和重新激活。对结直肠癌患者进行短期 BRB 干预导致 p16 去甲基化，并在结肠肿瘤组织的异常隐窝中重新表达该基因。因此，我们建议确定人结肠癌细胞和 ApcMin/+ 小鼠中 BRB 花青素对高甲基化沉默基因的去甲基化和重新激活是否与抑制肿瘤发生（具体目标 1）以及 DNMT1 在 BRB 花青素诱导的肿瘤抑制基因去甲基化中的作用（具体目标 2）有关。我们还将确定 BRB 是否影响从两项人类 BRB 干预试验中获得的样本中高甲基化沉默的肿瘤抑制基因的甲基化状态，及其与细胞增殖减少和息肉消退的关系（具体目标 3）。最后，我们将进行药代动力学研究，以确定以不同浓度的饮食给予 ApcMin/+ 小鼠时，人类结肠细胞、肠道组织和血清中花青素的摄取，以及尿中花青素及其代谢物的水平（具体目标 4）。最终，我们计划评估花青素预防人类结直肠癌的作用。 公众健康相关性：结肠癌是美国第三大流行癌症，也是美国癌症死亡的第三大原因。我们的实验室正在制定利用冻干浆果预防结肠癌的策略。我们现在建议评估浆果中的花青素去甲基化和重新激活结肠癌肿瘤抑制基因的能力。