Epoxygenase Mechanisms of Breast Cancer Progression

描述(申请人提供)：已在哺乳动物细胞中鉴定出花生四烯酸代谢的三种酶途径，包括环氧合酶、脂氧合酶和细胞色素P450环氧合酶，但只有前两种途径与人类癌症有关。HIV蛋白酶抑制剂利托那韦是一种有效的环氧合酶抑制剂，可以抑制乳腺癌移植瘤的生长，但其作用机制尚不清楚。环氧合酶促进环氧二十碳三烯酸(EET‘s)的产生，从而激活Akt激酶。该项目旨在确定环氧合酶是否是癌症治疗的靶点。有待检验的假设是，环氧合酶激活通过促进Akt磷酸化和癌细胞存活来促进乳腺癌的进展。其具体目的是：1.建立环氧合酶导致乳腺癌生长失调的分子机制；2.建立环氧合酶增强Ha-ras癌基因在乳腺癌中的致癌潜能。3.确定环氧合酶途径被激活，并需要Hsp90才能使癌细胞存活。使用电子捕获APCI-MS/MS方法的靶向脂质组学将被用于分析EET区域和立体异构体。将测试一种细菌环氧合酶与激活的Ha-ras在乳腺癌进展中的协同作用。这些研究将促进环氧合酶作为乳腺癌治疗靶点的进一步发展。

DESCRIPTION (provided by applicant): Three enzymatic pathways of arachidonic acid metabolism, involving cyclooxygenases, lipoxygenases, and cytochrome P450 epoxygenases, have been identified in mammalian cells, but only the first two have been linked to human cancer. The HIV protease inhibitor, ritonavir, is a potent inhibitor of epoxygenases that arrests the growth of breast cancer xenografts, but its mechanism of action is unknown. Epoxygenases promote the production of epoxyeicosatrienoic acids (EET's) that activate Akt kinase. This project seeks to determine whether epoxygenases are cancer therapeutic targets. The hypothesis to be tested is that epoxygenase activation promotes breast cancer progression by promoting Akt phosphorylation and cancer cell survival. The specific aims are: 1. To establish the molecular mechanisms by which epoxygenases cause growth dysregulation in breast cancer, 2. To establish that epoxygenases enhance the oncogenic potential of the Ha-ras oncogene in mammary carcinoma. 3. To establish that the epoxygenase pathway activates and requires Hsp90 for cancer cell survival. Targeted lipidomics using the method of electron capture APCI-MS/MS will be used to profile EET regio- and stereoisomers. A bacterial epoxygenase will be tested for cooperation with activated Ha-ras in breast cancer progression. These studies will promote further development of epoxygenases as targets for breast cancer therapeutics.