Breast Cancer Prevention by Dietary Phytochemicals

描述（由申请人提供）：乳腺癌化学预防的新方法是可取的，因为与这种疾病相关的许多风险因素不容易改变。此外，一些目前可用的针对乳腺癌的化学预防选择是次优的。无需强调，尽管靶向治疗取得了巨大进展，但乳腺癌仍然是全世界妇女癌症相关死亡的主要原因。本研究项目的持续目标是开发一种使用十字花科蔬菜成分异硫氰酸苄酯（BITC）化学预防乳腺癌的非内分泌策略。目前资助的研究目标几乎完全实现了显着的出版物。例如，我们证明了在饮食中给予BITC在转基因小鼠模型（MMTV-neu）中赋予针对乳腺癌的显著保护，而没有任何明显毒性的迹象。我们对最近发表和未发表的观察结果感到非常兴奋，这些观察结果支持BITC的新作用，可能有助于其化学预防作用，包括体外和体内抑制上皮-间充质转化（EMT）（已发表）和体外抑制乳腺癌干细胞（bCSC）的自我更新（未发表的观察结果）。我们还发现，BITC治疗激活Notch信号传导，这是EMT以及CSC自我更新的正调节因子。因此，通过实验测试BITC的Notch激活是否对其化学预防反应具有负面影响是唯一合乎逻辑的。同时，尿激酶型纤溶酶原激活物（uPA）及其受体（uPAR）的表达被BITC处理显著下调。由于uPAR过表达足以驱动乳腺癌细胞中的EMT和干性，因此进一步研究uPA/uPAR在BITC介导的EMT和bCSC自我更新抑制中的作用同样有价值。假设：本更新申请中的研究设计在逻辑上建立在这些令人兴奋的新观察结果的基础上，以检验一个刺激性假设，即BITC的乳腺癌化学预防是通过抑制uPA/uPAR系统介导的，从而抑制EMT和bCSC的自我更新，这可能适用于使用？分泌酶抑制剂。具体目标：拟议的研究利用乳腺癌的相关细胞和体内动物模型来确定：（1）BITC激活Notch对其促进乳腺癌化学预防作用的影响;（2）uPA/uPAR抑制在BITC介导的EMT抑制中的作用;（3）获得BITC对bCSC自我更新有效性的体内证据，并研究uPA/uPAR系统在这种反应中的作用。拟议研究的转化影响：迄今为止进行的研究为BITC对乳腺癌的化学预防功效提供了令人信服的临床前证据，但将这些发现有效转化为临床环境取决于对BITC驱动其化学预防反应的分子药理学的充分理解。临床试验设计没有充分认识到BITC的分子药理学可能是次优的。定义当前应用的创新包括拟议研究的转化价值以及新的研究方向。例如，目标1中提出的研究的内在价值在于涉及BITC和？-分泌酶抑制剂，以实现更大的化学预防功效。目的2可以鉴定BITC反应的生物标志物（例如，uPA和uPAR）在未来的临床研究中可能有用。发现预测BITC反应的生物标志物是一个同样有价值的目标，因为癌症发生率对于具有长潜伏期的恶性肿瘤（如乳腺癌）的终点过于严格。同样，BITC对bCSC的体内功效的实验验证可能（在未来）导致用于乳腺癌临床管理的新的基于BITC的方案，因为现有的机制模型规定了bCSC不仅在癌症发展和进展中而且在对治疗的抗性中的关键作用。 公共卫生相关性：乳腺癌是全球女性癌症相关死亡的主要原因。乳腺癌化学预防的新方法在临床上具有吸引力。本研究项目的长期目标是开发一种安全、廉价但有效的方案，用于使用十字花科蔬菜成分异硫氰酸苄酯（BITC）化学预防乳腺癌。在上一个资助期进行的研究为BITC对乳腺癌的疗效提供了临床前证据，但这些证据的有效转化 临床观察取决于对BITC分子药理学的充分理解。临床试验设计没有充分认识到BITC的分子药理学可能是次优的。定义当前应用的创新包括拟议研究的转化价值以及新的研究方向。

DESCRIPTION (provided by applicant): Novel approaches for chemoprevention of breast cancer are desirable because many risk factors associated with this disease are not easily modifiable. Moreover, some of the currently available chemopreventive options targeted against breast cancer are sub-optimal. Needless to emphasize that breast cancer continues to be a leading cause of cancer-related death in women worldwide despite tremendous advances towards targeted therapies. Ongoing objective of this research project is to develop a non-endocrine strategy for chemoprevention of breast cancer using cruciferous vegetable constituent Benzyl Isothiocyanate (BITC). Research objectives of the current funded grant were nearly fully achieved with notable publications. For example, we demonstrated that BITC administration in the diet confers significant protection against mammary cancer in a transgenic mouse model (MMTV-neu) without any signs of overt toxicity. We are extremely excited with our more recent published as well as unpublished observations underpinning novel actions of BITC potentially contributing to its chemopreventive effect, including inhibition of epithelial-mesenchymal transition (EMT) in vitro and in vivo (published) and suppression of self-renewal of breast cancer stem cells (bCSC) in vitro (unpublished observations). We also found that BITC treatment activates Notch signaling, which is a positive regulator of EMT as well as CSC self-renewal. Thus it is only logical to experimentally test whether Notch activation by BITC has negative impact on its chemopreventive response. At the same time, expression of urokinase-type plasminogen activator (uPA) and its receptor (uPAR) is significantly downregulated by BITC treatment. Because uPAR overexpression is sufficient to drive both EMT and stemness in breast cancer cells, further investigation of the role of uPA/uPAR in BITC-mediated inhibition of EMT and bCSC self-renewal is equally meritorious. Hypothesis: Research design in the present renewal application logically builds upon these exciting and novel observations to test a stimulating hypothesis that mammary cancer chemoprevention by BITC is mediated by inhibition of the uPA/uPAR system leading to suppression of EMT and self-renewal of bCSC, which may be amenable to augmentation by pharmacological suppression of Notch using a ?-secretase inhibitor. Specific Aims: Proposed research utilizes relevant cellular and in vivo animal models of breast cancer to determine: (1) the impact of Notch activation by BITC on its effects contributing to mammary cancer chemoprevention; (2) the contribution of uPA/uPAR suppression in BITC-mediated inhibition of EMT; and (3) obtain in vivo evidence for efficacy of BITC against bCSC self-renewal and to study the role of uPA/uPAR system in this response. Translational Impact of the Proposed Research: Studies conducted thus far provide compelling preclinical evidence for chemopreventive efficacy of BITC against breast cancer, but efficient translation of these findings into a clinical setting is dependent on a full understanding of the molecular pharmacology of BITC driving its chemopreventive responses. Clinical trial design without a full appreciation of the molecular pharmacology of BITC may be sub-optimal. Defining innovation of the current application includes translational merit of the proposed research as well as novel research directions. For example, intrinsic value of the studies proposed in Aim 1 resides in potential rational design of a combination regimen involving BITC and a ?-secretase inhibitor to achieve even greater chemopreventive efficacy. Aim 2 may identify biomarkers of BITC response (e.g., uPA and uPAR) potentially useful in future clinical investigations. Discovery of biomarker(s) predictive of BITC response is an equally meritorious objective because cancer incidence is too rigorous of an end point for malignancies with long latency such as breast cancer. Likewise, experimental validation of the in vivo efficacy of BITC against bCSC may (in future) lead to novel BITC- based regimens for clinical management of breast cancer because the existing mechanistic model stipulates critical role for bCSC not only in cancer development and progression but also in resistance to therapy. PUBLIC HEALTH RELEVANCE: Breast cancer is a leading cause of cancer-related death in women worldwide. Novel approaches for chemoprevention of breast cancer are clinically attractive. Long-term objective of this research project is to develop a safe and inexpensive but effective regimen for chemoprevention of breast cancer using cruciferous vegetable constituent benzyl isothiocyanate (BITC). Research conducted in the previous funding period provided preclinical evidence for efficacy of BITC against breast cancer, but efficient translation of these observations into a clinical setting depends on full appreciation of the molecular pharmacology of BITC. Clinical trial design without a full appreciation of the molecular pharmacology of BITC may be sub-optimal. Defining innovation of the current application includes translational merit of the proposed research as well as novel research directions.