Metabolic Regulation of 14-3-3zeta Acetylation in Breast Cancer

描述（由申请人提供）：乳腺癌是美国最常见的癌症之一，每八个妇女中就有一个在一生中患上这种疾病。除了是最普遍的癌症形式之一，它也是最具挑战性的治疗之一，每年有超过4万名妇女死于这种疾病。乳腺癌治疗通常使用细胞毒性药物对癌细胞造成损伤，激活一种称为细胞凋亡的程序性细胞死亡形式。细胞凋亡的激活导致半胱氨酸蛋白酶的激活，即半胱天冬酶，它可以切割蛋白质底物并导致细胞解体。细胞凋亡的抑制是癌症的中心特征之一，而癌细胞逃避细胞死亡的能力一直是乳腺癌治疗的主要障碍。Caspase 2 （C2）已被证明是乳腺癌化疗反应中细胞凋亡的关键启动物。在一个模型实验系统中，我们的实验室先前已经表明，C2的激活可以通过结合一个小信号分子14-3-3？14-3-3？是由14-3-3？乙酰化和这种修饰是由细胞代谢状态控制的。随着大量研究表明癌细胞通常具有异常的代谢途径，我们提出乳腺癌细胞调节14-3-3？在基因毒性压力下生存。阐明14-3-3乙酰化的变化？可能有助于乳腺癌细胞逃避细胞毒性药物的细胞死亡能力，我们建议确定调节14-3-3？乙酰化、代谢控制机制及14-3-3？正常和乳腺肿瘤样本中的乙酰化。此外，我们的目标是探索如何调节乙酰化将改变乳腺癌细胞的化学反应性，无论是在培养和小鼠模型。拟议的研究将利用已建立的具有不同化学敏感性的乳腺癌细胞系，因此我们将使用特定的乙酰化酶和去乙酰化酶抑制剂进行筛选，以确定控制14-3-3？乙酰化作用。然后通过监测不同代谢条件下酶结合和活性的变化来评估代谢控制的机制。另外，我们将确定14-3-3？通过分析正常和原发人类肿瘤样本/切片乙酰化14-3-3？使用免疫组织化学。最后，为了确定调节乙酰化是否会改变乳腺癌细胞的化学反应性，相关抑制剂将与化疗药物联合使用，并检测其诱导乳腺癌细胞系和异种移植肿瘤细胞死亡的能力。我们期望增强14-3-3？乙酰化将增加乳腺癌细胞对化疗诱导的细胞凋亡的易感性，可能导致发现一种新的治疗方法，可以与标准化疗联合使用，以更有效地治疗乳腺癌。

DESCRIPTION (provided by applicant): Breast cancer is one of the most prevalent forms of cancer in the United States, with one in every eight women developing the disease over the course of a lifetime. Besides being one of the most prevalent forms of cancer, it is also one of the most challenging to treat, with more than 40,000 women dying from the disease each year. Breast cancer therapies often utilize cytotoxic agents that cause damage to cancer cells, activating a form of programmed cell death called apoptosis. Activation of apoptosis results in the activation of cysteine proteases, known as caspases, which cleave protein substrates and lead to a disassembly of the cell. Inhibition of apoptosis is one of the central hallmarks of cance and the ability of cancer cells to evade cell death has been a major obstacle in breast cancer treatment. Caspase 2 (C2) has been shown to be a critical initiator of apoptosis in response to breast cancer chemotherapeutics. In a model experimental system, our lab has shown previously that activation of C2 can be regulated by metabolism through binding of a small signaling molecule, 14-3-3?. The release of 14-3-3? from C2 is regulated by 14-3-3? acetylation and this modification is controlled by the metabolic status of the cell. With extensive studies showing that cancer cells commonly have abnormal metabolic pathways, we propose that breast cancer cells modulate acetylation of 14-3-3? to survive genotoxic stressors. To elucidate how alterations in acetylation of 14-3-3? may contribute to the ability of breast cancer cells to evade cell death by cytotoxic agents, we propose to determine the enzymes regulating 14-3-3? acetylation, the mechanism of metabolic control, and the status of 14-3-3? acetylation in normal and breast tumor samples. Furthermore, we aim to explore how modulating acetylation will alter the chemoresponsiveness of breast cancer cells, both in culture and mouse models. The proposed research will utilize established breast cancer cell lines of varying chemosensitivities, whereby we will screen using specific acetylase and deacetylase inhibitors to identify the enzymes controlling 14-3-3? acetylation. The mechanism of metabolic control will then be evaluated by monitoring changes in enzyme binding and activity under different metabolic conditions. In addition, we will determine if the acetylation status of 14-3-3? is altered in breas cancer by analyzing both normal and primary human tumor samples/sections for acetylated 14-3-3? using immunohistochemistry. Finally, to determine whether modulating acetylation alters the chemoresponsiveness of breast cancer cells, relevant inhibitors will be combined with chemotherapeutic agents and assayed for their ability to induce cell death in both breast cancer cell lines and xenografted tumors. We expect that enhancing 14-3-3? acetylation will increase the susceptibility of breast cancer cells to chemotherapy-induced apoptosis, potentially leading to the discovery of a new therapy that can be used in combination with standard chemotherapies for more effective breast cancer treatments.