Fatty Acid Synthase /Molecular Target /Breast Cancer The

脂肪酸合酶/分子靶标/乳腺癌

• 批准号: 6964059
• 负责人: RUTH LUPU
• 金额: $ 41.67万
• 依托单位: NORTHSHORE UNIVERSITY HEALTHSYSTEM
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-16 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6964059
• 关键词: antineoplastics; athymic mouse; breast neoplasms; cancer prevention; cell growth regulation; cell line; chemoprevention; clinical research; drug resistance; enzyme activity; fatty acid synthase; female; gene expression; human genetic material tag; human tissue; lipid biosynthesis; mammary epithelium; molecular oncology; neoplasm /cancer chemotherapy; neoplasm /cancer genetics; neoplastic process; neoplastic transformation; oncogenes; preneoplastic state; protein structure function; serology /serodiagnosis

DESCRIPTION (provided by applicant): There are two sources of fatty acids for animals, exogenous (dietary) fatty acids and de novo endogenous biosynthesis, of which the latter is regulated by Fatty Acid Synthase (FAS). The high level of fat in the Western diet has been implicated in the development of many human malignancies, including breast cancer. Indeed, dietary fatty acids have emerged as an intense focus of research and controversy in breast cancer etiology, prevention and/or therapy. Human breast cancer cell lines and breast tumors exhibit overexpression and hyperactivity of FAS, with FAS-overexpressing breast cancer tumors demonstrating shortened disease-free intervals or overall survivals. Moreover, FAS overexpression can also be identified in intraductal and lobular in situ breast carcinoma, pre-neoplastic lesions associated with increased risk for the development of infiltrating breast cancer, while elevated serum FAS levels have been identified in breast cancer patients with different clinical stages compared with healthy subjects. Interestingly, the relative absence of endogenous fatty acid biosynthesis in normal tissues has led to the notion that FAS blockade should provide a highly selective basis for anticancer therapy. These data, altogether, reveal that FAS-dependent de novo fatty biogenesis, an anabolic energy-storage pathway largely considered of minor importance in humans, may ultimately be used for diagnosis, prognosis, early intervention, and treatment of breast carcinomas. As a part of our efforts to assess the role of FAS signaling on the survival and proliferation of human breast cancer cells, we have identified a novel bi-directional molecular link between breast cancer-associated FAS and Her-2/neu oncogene. A positive correlation was found between high levels of FAS expression and the amplification and/or overexpression of Her-2/neu oncogene. Pharmacological inhibition of FAS by the natural mycotoxin cerulenin, or a related synthetic compound, C75 or a statin Orlistat, negatively regulated Her-2/neu-encoded p185Her-2/neu oncoprotein and its associated tyrosine-kinase activity. When FAS gene expression was silenced by RNA interference (RNAi) a dramatic decrease of p185Her-2/neu expression occurred in the Her-2/neu-overexpressing cells, whereas there was no effect in cells expressing physiological levels of Her-2/neu. Remarkably, pharmacological and RNAi mediated downregulation of Her-2/neu and, concomitantly, caused a prominent up-regulation of PEA3, a transcriptional represser of Her-2/neu. Furthermore, a simultaneous targeting of FAS and Her-2/neu signaling by chemical FAS inhibitors and the humanized monoclonal antibody directed against p185Her-2/neu trastuzumab (Herceptin(tm)), resulted in a synergistic growth inhibitory effect towards Her-2/neu overexpressing cells. These findings support the hypothesis that breast cancer-associated FAS, rather than simply the epigenetic consequence of aberrant activation of up-stream transduction pathways (e.g. PI-3K/AKT, Ras/Raf/MEK/ERK) plays an active role in breast cancer evolution by regulating oncogenic proteins closely related to malignant transformation. Indeed, our pioneer observations demonstrating the ability of FAS-driven signaling to regulate the expression and/or activity of Her-2/neu (erbB-2) oncogene strongly suggest that FAS may actively participate in the triggering, maintenance and/or enhancement of the breast cancer malignant phenotype. Therefore our aims are: 1) To characterize the molecular mechanism determining the early up-regulation of FAS in breast cancer and to evaluate the oncogenic potential of FAS-catalyzed endogenous lipogenesis in normal breast epithelial cell models. We will determine how FAS contributes to the pre-neoplastic transformation of noncommittal breast epithelial cells (normal cells) and whether FAS overexpression sets off malignant transformation. 2) To evaluate the therapeutic relevance of targeting FAS in Her-2/neu-overexpressing breast cancer in vitro and in vivo on the basis of the novel bidirectional molecular link between FAS and the Her-2/neu that we recently demonstrated. 3) We will characterize the molecular mechanisms underlying the bi-directional molecular cross-talk between FAS and Her-2/neu. In addition, we will assess whether FAS blockade represents a novel sensitizing strategy to reverse trastuzumab (Herceptin(tm)) resistance in Her-2/neu-overexpressing breast carcinomas. 4) To evaluate whether inhibition of FAS activity modulates breast cancer cell sensitivity to chemotherapy-induced cell damage and to evaluate whether silencing FAS expression modulates breast cancer cell sensitivity to chemotherapy-induced cell damage. 5) To determine the molecular relevance and clinical impact of FAS expression in breast cancer progression, and to evaluate the value and clinical contribution to the treatment decision provided by the assessment of circulating serum levels of FAS. Our study speculates that constitutive up-regulation of FAS in breast cancer disease represents an early metabolic response for survival to the hypoxic and acidic microenvironment of pre-malignant breast cancer phases. This epigenetic up-regulation of FAS in early stages of breast cancer may result, in turn, in a metabolic strategy of selection to maintain high proliferation rates of surviving cells. The characterization of FAS as a novel metabolic oncogene will allow an invaluable adjunct to gene expression profiling or proteomics in the characterization of biologically aggressive subsets of breast carcinomas. Moreover, the predictive potential of measurement FAS expression will help in the selection of better responders to cytotoxic drugs, and Her-2/neu-targeted therapies. Considering that drug resistance hampers successful breast cancer treatment, and its prevention or reversal is still awaiting new sensitizing strategies or pharmaceuticals, our study will open a new molecular avenue based on the specific targeting of FAS-dependent neoplastic lipogenesis, a valuable specific molecular target that is minimally activated in normal tissues.

描述（由申请人提供）：动物有两种脂肪酸来源，外源性（饮食）脂肪酸和从头内源性生物合成，后者受脂肪酸合酶（FAS）调节。西方饮食中高水平的脂肪与包括乳腺癌在内的许多人类恶性肿瘤的发展有关。实际上，饮食脂肪酸已成为乳腺癌病因，预防和/或治疗中研究和争议的强烈重点。人类乳腺癌细胞系和乳腺肿瘤表现出FAS的过表达和过度活跃性，过表达FAS的乳腺癌肿瘤表明无病的间隔缩短或总体存活。此外，还可以鉴定出在导管内和小叶原位乳腺癌，与健康临床患者相比，在不同临床阶段的乳腺癌患者中鉴定出与浸润性乳腺癌的风险增加相关的乳腺癌的风险增加，而血清FAS水平升高，而血清FAS水平升高。有趣的是，在正常组织中相对缺乏内源性脂肪酸生物合成，导致FAS阻断应为抗癌治疗提供高度选择性的基础。这些数据总共表明，依赖FAS的从头脂肪生物发生，这是一种在人类中很大程度上考虑的合成代谢能量储存途径，最终可能用于诊断，预后，早期干预和乳腺癌的治疗。作为我们评估FAS信号传导对人乳腺癌细胞生存和增殖的作用的努力的一部分，我们已经确定了与乳腺癌相关的FAS和HER​​-2/NEU ONCOGENE之间的新型双向分子联系。在高水平的Fas表达与HER-2/NEU癌基因的扩增和/或过表达之间发现了正相关。天然霉菌毒素cerulenin或相关的合成化合物C75或汀类药物Orlistat对FAS的药理抑制作用，对HER-2/NEU代码的P185HER-2/NEU癌蛋白及其相关的酪氨酸基因酶活性。当RNA干扰（RNAI）沉默FAS基因表达时，在HER-2/neu过表达的细胞中，P185HER-2/NEU表达的急剧下降发生，而在表达Her-2/neu生理水平的细胞中，没有影响。值得注意的是，药理学和RNAi介导了HER-2/NEU的下调，并同时引起了HER-2/neu的转录压抑子PEA3的明显上调。此外，化学FAS抑制剂和针对P185HER-2/NEU曲妥珠单抗（Herceptin（TM））的化学FAS抑制剂和人源化的单克隆抗体的FAS和HER​​-2/NEU信号的同时靶向，导致对Her-2/Neu neu neu过表达的细胞产生协同作用。这些发现支持了以下假设：乳腺癌相关的FA，而不是仅仅是激活上游转导途径异常激活（例如PI-3K/AKT，RAS/RAS/RAF/MEK/ERK）的表观遗传学后果，通过调节与癌蛋白密切相关的非对癌素的转化在乳腺癌演化中起积极作用。的确，我们的先驱观察表明，通过FAS驱动的信号传导调节HER-2/NEU（ERBB-2）癌基的表达和/或活性的能力强烈表明，FAS可以积极参与触发，维持和/或增强乳腺癌恶性表型的触发，维持和/或增强。因此，我们的目的是：1）表征确定乳腺癌中Fas早期上调的分子机制，并评估正常乳腺上皮细胞模型中Fas催化的内源性脂质形成的致癌潜力。我们将确定FAS如何促进非乳房上皮细胞（正常细胞）的肿瘤前转化以及FAS过表达是否促进了恶性转化。 2）根据我们最近证明的Fas与Her-2/Neu之间的新型双向分子链接，在体外和体内评估靶向FAS的治疗相关性。 3）我们将表征FAS和HER​​-2/NEU之间双向分子串扰的分子机制。此外，我们将评估FAS封锁是否代表了一种新型的敏感策略，以逆转曲妥珠单抗（Herceptin（TM））在HER-2/neu过表达的乳腺癌中的抗性。 4）评估FAS活性的抑制是否调节乳腺癌细胞对化学疗法诱导的细胞损伤的敏感性，并评估沉默的FAS表达是否调节乳腺癌细胞对化学疗法诱导的细胞损伤的敏感性。 5）确定FAS表达在乳腺癌进展中的分子相关性和临床影响，并评估评估FAS循环血清水平所提供的治疗决策的价值和临床贡献。我们的研究推测，乳腺癌疾病中Fas的本构上调代表了生存的早期代谢反应，以对乳腺癌前乳腺癌阶段的低氧和酸性微环境生存。在乳腺癌的早期阶段，FAS的表观遗传学上调可能会导致选择的代谢策略，以维持幸存细胞的高增殖率。 FA作为一种新型代谢癌基因的表征将允许在乳腺癌的生物学上具有攻击性的亚群表征中对基因表达分析或蛋白质组学的宝贵辅助。此外，测量FAS表达的预测潜力将有助于选择对细胞毒性药物的更好反应者和HER-2/NEU靶向疗法。考虑到耐药性会阻碍成功的乳腺癌治疗，并且其预防或逆转仍在等待新的敏化策略或药物，我们的研究将基于基于FAS依赖性的肿瘤脂质发生的特异性靶向，在正常组织中最少激活了一种有价值的特定特异性分子靶标的新分子大道。