Curcuma Longa: epigenetic effects in prostate and colon cancer

说明(申请人提供)：姜黄根的产品通常含有三种主要成分：姜黄素(Cur；~77%)、去甲氧基姜黄素(~17%)和双去甲氧基姜黄素(~3%)，通常用作植物膳食补充剂。这项研究项目的长期目标是开发一种安全有效的策略，在美国使用C.L.预防包括前列腺癌(PCA)和结直肠癌(CRC)在内的疾病。前列腺癌仍然是美国男性最常见的恶性肿瘤，估计2009年新增病例192,280例，死亡27,360人，而结直肠癌是40岁至79岁男性癌症死亡的第二大常见原因，2010年诊断的女性癌症死亡人数估计为53,439人，是第三大癌症死亡原因。本申请中提出的研究的基本原理来自我们已发表和未发表的初步研究表明：(1)在PCa中，Cur显示了对裸鼠人PC-3移植瘤和TRAMP小鼠的前列腺癌的体内抑制；(2)在CRC中，Cur诱导人HT-29结肠癌细胞凋亡并抑制NFkB；Cur的类似物二苯甲酰甲烷，在APCmin小鼠中抑制腺瘤，在AOM-DSS小鼠中抑制CRC；(3)Cur通过Nrf2 KO小鼠调节肠道中依赖Nrf2的基因；(4)随着TRAMP小鼠PCa的进展，存在抗氧化应激转录因子Nrf2和Nrf2靶基因的缺失；(5)Cur可导致TRAMP前列腺癌中与肿瘤抑制相关的Nrf2和Nrf2靶基因UGT1A1的重新表达；(6)Nrf2基因在TRAMP肿瘤和TRAMP C1细胞系中通过启动子CpG超甲基化而受到表观调控；(7)Cur逆转了96个基因启动子中基因的甲基化状态，其中已有报道在人前列腺癌中存在高甲基化；(8)Cur逆转已建立的肿瘤甲基化标志物基因Neurog1的表达，增加了Neurog1基因的去甲基化，并增加了Neurog1mRNA和蛋白的表达。然而，尽管有这些可喜的结果，我们对Cur/C.L.在疾病预防中的表观遗传学机制的理解仍然存在重大差距，包括人类前列腺癌和结直肠癌的癌症预防。根据我们的初步研究结果，我们假设C.L./Cur治疗引起表观遗传修饰，从而预防PCa和CRC，具体目的有三：(1)确定姜黄(Curuma Longa(C.L.)(2)研究C.L.对AOM/DSS诱导的结直肠癌的化学预防作用和表观遗传学改变；(3)阐明C.L.在TraMP C1、LNCaP和HT29细胞培养系统中对体内AIMS 1和2的基因调控的表观遗传学机制。

DESCRIPTION (provided by applicant): The products of root of Curcuma longa (C.L.), usually contain three major components, curcumin (CUR; ~77%), demethoxycurcumin (~17%) and bis-demethoxycurcumin (~3%), they are commonly used as botanical dietary supplements. The long term goal of this research project is to develop a safe and effective strategy to use C.L. in preventing diseases including prostate cancer (PCa) and colorectal cancer (CRC) in the US. PCa remains the most common malignancy in American men with an estimated 192,280 new cases and 27,360 deaths were expected in 2009, whereas CRC is the second most common cause of cancer death among men ages 40 to 79 years, and the third leading cause of cancer mortality in women with an estimated 53,439 new cases were diagnosed in 2010. Rationale for the studies proposed in this application is derived from our published as well as preliminary unpublished studies demonstrating that: (1) in PCa, CUR shows in vivo inhibition of prostate tumors in nude mice human PC-3 xenograft and TRAMP mice; (2) in CRC, CUR induces apoptosis in human HT-29 colon cancer cells and inhibits NFkB; an analog of CUR dibenzoylmethane, inhibits adenomas in APCmin mice, and CRC in AOM-DSS mice; (3) CUR regulate Nrf2-dependent genes in the intestine using Nrf2 KO mice; (4) As TRAMP mouse PCa progresses, there is a loss of the anti-oxidative stress transcription factor Nrf2 and Nrf2-target genes; (5) Feeding TRAMP mice with CUR resulted in re-expression of Nrf2 and Nrf2-target gene UGT1A1 in the TRAMP prostate tumor correlating with tumor suppression; (6) Nrf2 gene is epigenetically regulated in TRAMP tumor and TRAMP C1 cell line through promoter CpG hypermethylation; (7) CUR reverses the methylation status of genes from a panel of 96 gene promoters of which their hypermethylation has been reported in human PCa; (8) CUR reverses the expression of Neurog1 gene, an established cancer methylation marker gene, with increase in de-methylation of Neurog1 gene coupled with increase Neurog1 mRNA and protein. Despite these promising results, however, significant gaps exist in our understanding of the epigenetic mechanisms of CUR/C.L. in disease prevention including cancer prevention of human PCa and CRC. Based on the results of our preliminary studies we hypothesize that C.L./CUR treatment causes epigenetic modifications leading to prevention of PCa and CRC with three Specific Aims: (1) To determine the epigenetic alterations elicited by Curcuma Longa (C.L.) in prevention of prostate tumorigenesis in TRAMP mice; (2) To investigate the chemopreventive efficacy and epigenetic alterations of C.L. in AOM/DSS-induced CRC; and (3) To elucidate the in vitro epigenetic mechanisms of regulation of the genes obtained from in vivo Aims one and two by C.L. in TRAMP C1, LNCaP, and HT29 cell culture system.