Combined use of green tea and quercetin in prostate cancer

绿茶和槲皮素联合使用治疗前列腺癌

• 批准号: 8047388
• 负责人: Susanne Margarete Henning
• 金额: $ 7.7万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-25 至 2011-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8047388
• 关键词: Animals; Apoptosis; Biological Availability; Catechol O-Methyltransferase; Catechols; Cell Culture Techniques; Cell Proliferation; Cells; Chemicals; Chemoprevention; Chemopreventive Agent; Chromosomes, Human, Pair 10; Cytosine; DNA Methyltransferase; DNA Modification Methylases; Detection; Development; Diagnosis; Diagnostic Neoplasm Staging; Diet; Enzymes; Epidemiology; Epigallocatechin Gallate; Flavonoids; Gene Expression; Green tea; Health; Health Benefit; High Pressure Liquid Chromatography; Human; Immunohistochemistry; In Vitro; Incubated; Induction of Apoptosis; Kidney; Knockout Mice; LNCaP; Laboratories; Lead; Liver; Lung; Malignant neoplasm of prostate; Measures; Metabolism; Methylation; Mus; Operative Surgical Procedures; P-Glycoprotein; P-Glycoproteins; PC3 cell line; PTEN gene; Pattern; Phase; Play; Preventive; Prostate; Prostatic Neoplasms; Publications; Quercetin; Role; SCID Mice; Structure; Tea; Testing; Time; Tissues; Transgenic Organisms; Tumor Suppressor Proteins; Tumor Tissue; Tumor Volume; Tumor Weights; Tumor stage; Urine; Water; Western Blotting; Work; Xenograft procedure; base; cancer cell; cell growth; drinking water; enzyme activity; epicatechin; epicatechin gallate; fruits and vegetables; gallocatechol; in vivo; inhibitor/antagonist; mRNA Expression; men; mouse model; novel; polyphenol; prostate cancer prevention; protein expression; serum PSA; tumor; tumor growth; tumor xenograft

DESCRIPTION (provided by applicant): The anticarcinogenic activity of green tea has been demonstrated in many epidemiological, animal and cell culture studies. The main green tea polyphenols (GTPs) in brewed green tea (GT) responsible for the health benefits are epigallocatechin gallate (EGCG) and epigallocatechin (EGC), with smaller amounts of epicatechin (EC) and epicatechin gallate (ECG). Their limited bioavailability and high metabolism (conjugation and methylation) may decrease the potential of GT in chemoprevention. We determined that 50 percent or more of GTPs in human prostate tissue and urine is found in methylated form and that methylation significantly decreased the anticarcinogenic activity of EGCG. Catechol-O-methyltransferase (COMT) is the enzyme responsible for methylation of polyphenols with a catechol structure. Catechol-compounds such as EGCG and quercetin, a natural flavonoid occurring in many fruits and vegetable, inhibit COMT activity in prostate cancer cells (LNCaP). Co-treatment of quercetin and EGCG enhanced the COMT inhibitory effect, decreased EGCG methylation and increased EGCG bioavailability significantly. Therefore it is our hypothesis that co-treatment with quercetin and green tea will increase the chemopreventive activity of GT by inhibiting EGCG methylation and increasing the bioavailability in prostate cancer (CaP). We will test our hypothesis and investigate the mechanism using two different mouse models: A) by treating severe combined immunodeficient (SCID) mice inoculated with LNCaP xenograft tumors with green tea (GT) alone, GT and 0.2% quercetin (Q)-diet, GT+0.4%Q-diet, 0.2%Q-diet alone, 0.4%Q-diet alone or water control; and B) by treating transgenic phosphatase and tensin homolog deleted on chromosome 10 (PTEN) knock out mice with GT alone, Q alone and GT+ Q together using the concentration shown to be most effective for SCID mice. Lack of the tumor suppressor PTEN in the mouse prostate recapitulates many of the pathological features of CaP development in humans. To determine the chemopreventive activity we will measure tumor weight and volume, tumor stage, and cell proliferation, apoptosis by immunohistochemistry. Tumor tissue will be used to measure COMT and 5- cytosine DNA methyltransferase 1 (DNMT1) enzyme activity as well as protein and gene expression using Western blot and quantitative real-time PCR. Multidrug resistance proteins (MRP) may play a role in the increase in bioavailability of EGCG by co-treatment with quercetin. Therefore we will also determine protein and gene expression of MRP1 and MRP2 in tumor tissue. The effect on bioavailability will be determined by analysis of tea polyphenols, quercetin and their metabolites in tumor tissue, liver, lung, and kidney by high performance liquid chromatography and coularray electrochemical detection. This novel combination of natural complementary and alternative agents utilizes the ability of quercetin to reduce the methylation of GTPs and increase their bioavailability at the same time. This novel treatment will retain the non-toxic character of green tea and at the same time increase its activity in chemoprevention of CaP.

描述（由申请人提供）： 绿茶的抗癌活性已在许多流行病学、动物和细胞培养研究中得到证实。冲泡绿茶 (GT) 中对健康有益的主要绿茶多酚 (GTP) 是表没食子儿茶素没食子酸酯 (EGCG) 和表没食子儿茶素 (EGC)，以及少量的表儿茶素 (EC) 和表儿茶素没食子酸酯 (ECG)。它们有限的生物利用度和高代谢（结合和甲基化）可能会降低 GT 在化学预防方面的潜力。我们确定，人类前列腺组织和尿液中 50% 或更多的 GTP 是以甲基化形式存在的，并且甲基化显着降低了 EGCG 的抗癌活性。儿茶酚-O-甲基转移酶（COMT）是负责具有儿茶酚结构的多酚甲基化的酶。儿茶酚化合物，例如 EGCG 和槲皮素（一种存在于许多水果和蔬菜中的天然黄酮类化合物），可抑制前列腺癌细胞 (LNCaP) 中的 COMT 活性。槲皮素和EGCG共同处理显着增强了COMT抑制作用，降低了EGCG甲基化，显着提高了EGCG生物利用度。因此，我们假设槲皮素和绿茶联合治疗将通过抑制 EGCG 甲基化并增加前列腺癌 (CaP) 的生物利用度来增加 GT 的化学预防活性。我们将使用两种不同的小鼠模型来检验我们的假设并研究其机制：A) 通过仅用绿茶 (GT)、GT 和 0.2% 槲皮素 (Q)-饮食、GT+0.4%Q-饮食、仅 0.2%Q-饮食、仅 0.4%Q-饮食或水对照治疗接种 LNCaP 异种移植肿瘤的严重联合免疫缺陷 (SCID) 小鼠； B)通过使用对SCID小鼠最有效的浓度，用单独的GT、单独的Q和GT+Q一起治疗转基因磷酸酶和在10号染色体上缺失的张力蛋白同源物(PTEN)敲除小鼠。小鼠前列腺中肿瘤抑制因子 PTEN 的缺乏概括了人类 CaP 发育的许多病理特征。为了确定化学预防活性，我们将通过免疫组织化学测量肿瘤重量和体积、肿瘤阶段以及细胞增殖和凋亡。肿瘤组织将用于使用蛋白质印迹和定量实时 PCR 来测量 COMT 和 5-胞嘧啶 DNA 甲基转移酶 1 (DNMT1) 酶活性以及蛋白质和基因表达。多药耐药蛋白 (MRP) 可能在与槲皮素联合治疗提高 EGCG 生物利用度方面发挥作用。因此我们还将测定肿瘤组织中MRP1和MRP2的蛋白和基因表达。通过高效液相色谱和coularray电化学检测分析肿瘤组织、肝、肺、肾中的茶多酚、槲皮素及其代谢物，确定对生物利用度的影响。这种天然补充剂和替代剂的新型组合利用槲皮素的能力来减少 GTP 的甲基化，同时提高其生物利用度。这种新颖的治疗方法将保留绿茶的无毒特性，同时增加其化学预防 CaP 的活性。