Clinical Study of Disposition and Biological Activity of d-Limonene

描述(由申请人提供)： D-柠檬烯是柑橘类水果精油中的主要成分，是一种单环单萜烯。研究表明，口服d-柠檬烯可预防致癌物诱发的大鼠乳腺癌的发生和发展，并能显着缓解晚期乳腺癌，且未发现任何明显的全身毒性。大多数单环单萜的临床开发工作都集中在柠檬烯的羟基化类似物紫苏醇上。这些在晚期癌症患者中进行的试验表明，紫苏醇的临床抗肿瘤活性在安全剂量下不太可能发生。据报道，只有一次d-柠檬烯的临床试验。这项试验也在晚期癌症患者中进行；一名乳腺癌患者的部分反应维持了11个月，3名结直肠癌患者的病情稳定超过6个月。紫苏醇和柠檬烯尽管结构相似，但在体内表现出不同的处置模式。紫苏醇口服后没有生物利用度。它经历了显著的首过代谢，几乎完全转化为两种极性代谢物，紫苏酸和二氢紫苏酸。由于它们的极性，这些代谢物的组织分布很可能是有限的，从而限制了它们在体内的组织活性。与紫苏醇不同，d-柠檬烯在口服后在人体内是生物可利用的。由于其高亲脂性，d-柠檬烯已被证明在啮齿动物的脂肪和乳腺组织中有良好的分布。由我们的研究小组产生的新的初步数据显示，d-柠檬烯在人类的脂肪组织中广泛分布。我们建议进行一项试验性临床研究，以确定乳房组织中d-柠檬烯的生物利用度及其相关的生物活性，这些妇女最近被诊断为导管原位癌、小叶原位癌或非典型导管增生症而选择接受切除手术。这项研究的总体目标是确定d-柠檬烯的乳房组织分布及其对乳房组织和血清替代终点生物标志物的相关影响。我们假设d-柠檬烯将广泛分布于人的乳房组织，并发挥生物活性，从而预防乳腺癌。具体地说，我们计划1)确定d-柠檬烯是否会广泛分布到乳房组织，并达到先前临床前研究中有效的乳房组织药物浓度范围；2)确定每天2-6周的d-柠檬烯给药对乳房组织和血清中替代终点生物标记物的调节作用。这项拟议的试验对于确定d-柠檬烯是否应该被进一步评估为乳腺癌预防药物具有重要意义。长期目标是进行长期干预试验，以确定d-柠檬烯预防乳腺癌的活性，并进行转化性临床研究，以了解d-柠檬烯在阻止/抑制/逆转乳腺癌发生过程中的作用。公共卫生相关性：项目叙述柠檬烯是柑橘类水果精油的主要成分。它已经在临床前模型系统中展示了良好的乳腺癌预防和治疗效果。这项赠款申请建议进行一项早期临床研究，以评估柠檬烯在乳房组织中的分布及其相关的生物活性，这些妇女最近被诊断为乳腺癌原位癌或非典型导管增生症，计划接受明确的手术，服用2到6周的柠檬烯。本研究将有助于评估开发柠檬烯作为乳腺癌预防药物的潜力。

DESCRIPTION (provided by applicant): d-Limonene, a monocyclic monoterpene, is a major component in the essential oils of citrus fruits. Oral feeding of d-limonene has been shown to prevent carcinogen-induced rat mammary carcinoma during the initiation and promotion stages as well as cause significant regression of advanced mammary carcinomas without any observable systemic toxicity. Most clinical development efforts of monocyclic monoterpenes have focused on a hydroxylated analog of limonene, perillyl alcohol. These trials, conducted in advanced cancer patients, suggested that the clinical antitumor activity of perillyl alcohol is not likely to occur at safe doses. There is only one reported clinical trial of d-limonene. This trial was also conducted in advanced cancer patients; one partial response in a breast cancer patient was maintained for 11 months and three patients with colorectal carcinoma showed stabilization of disease for longer than 6 months. Despite of their structural similarities, perillyl alcohol and limonene exhibited distinct in vivo disposition pattern. Perillyl alcohol is not bioavailable after oral administration. It undergoes significant first-pass metabolism and is converted almost completely to two polar metabolites, perillic acid and dihydroperillic acid. Due to their polarity, the tissue distribution of these metabolites is likely to be limited, thus limiting their in vivo tissue activities. Unlike perillyl alcohol, d-limonene is bioavailable in humans after oral administration. Because of its high lipophilicity, d-limonene has been shown to distribute favorably to adipose and mammary tissues in rodents. New preliminary data generated from our research group showed that d-limonene distributes extensively to adipose tissue in humans. We propose to conduct a pilot clinical study to determine the breast tissue bioavailability of d- limonene and its associated biological activities in women with a recent diagnosis of ductal carcinoma in situ, lobular carcinoma in situ, or atypical ductal hyperplasia elected to undergo excision surgery. The overall objective of the study is to determine the breast tissue distribution of d-limonene and its associated effects on breast tissue and serum surrogate endpoint biomarkers. We hypothesize that d- limonene will distribute extensively to human breast tissue and exert biological activities that would lead to breast cancer prevention. Specifically, we plan to 1) to determine whether d-limonene will distribute extensively to the breast tissue and reach a breast tissue drug concentration range found effectively in previous pre-clinical studies and 2) to determine the modulating effects of 2-6 weeks of daily d-limonene administration on surrogate endpoint biomarkers in the breast tissue and serum. The proposed trial is important in order to determine whether d-limonene should be further evaluated as a breast cancer preventive agent. The long-term goals are to conduct long-term intervention trials to determine the breast cancer preventive activity of d-limonene and to conduct translational clinical research in understanding the effect of d-limonene on arresting/inhibiting/reversing the breast cancer carcinogenesis process. PUBLIC HEALTH RELEVANCE: Project Narrative Limonene is a major component in the essential oils of citrus fruits. It has demonstrated promising breast cancer preventive and therapeutic effects in preclinical model systems. This grant application proposes to conduct an early phase clinical study to evaluate the distribution of limonene to the breast tissue and its associated biological activities after 2 to 6 weeks of limonene dosing in women with a recent diagnosis of breast carcinoma in situ or atypical ductal hyperplasia scheduled to undergo definitive surgery. This study will help evaluate the potentials of developing limonene as a breast cancer preventive agent.