ESTROGEN RECEPTOR-DIRECTED THERAPY WITH AUGER ELECTRONS

使用螺旋电子进行雌激素受体定向治疗

• 批准号: 3194233
• 负责人: EUGENE R DE-SOMBRE
• 金额: $ 23.15万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-04-01 至 1992-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3194233
• 关键词: DNA binding protein; athymic mouse; autoradiography; disease /disorder model; electron radiation; estrogen receptors; hormone related neoplasm /cancer; immunocytochemistry; laboratory rat; monoclonal antibody; neoplasm /cancer radiation therapy; neoplastic cell; radiobiology; receptor binding; tissue /cell culture; transfection

The long term goal of this research is to establish the feasibility and applicability of steroid receptor-directed therapy using Auger electron emitting nuclides covalently attached to specific receptor binding ligands to treat cancers containing the appropriate steroid hormone receptors. The approach proposed is based on 1) the known ability of the steroid receptors to form high affinity complexes with the receptor ligands and to bring them into intimate association with regions of DNA in the nucleus, 2) the ability to synthesize bromo- and iodo-ligands which retain high affinity for the steroid receptors, 3) the availability of nuclides of bromine and iodine which decay by emission of Auger electrons, and 4) the highly effective DNA-lytic radiation of Auger electrons emitted in DNA. While endocrine therapies are highly effective in those estrogen receptor positive cancers, such as breast, and endometrial carcinomas, which respond, only about half, at best, of the receptor positive cancer patients obtain remissions following such treatment. And certain cancers, such as ovarian cancers, which often contain estrogen receptor (ER) seldom respond to endocrine treatment. The limitations of current endocrine therapies agree that they require that the growth of the cancer depends on the hormone, and furthermore are cytostatic in nature. On the other hand steroid receptor-directed therapy with Auger electron emitting, receptor- binding ligands would be expected to depend only upon the presence of the receptor in the cell nucleus and, by causing double stranded DNA breads, should kill the cells. Preliminary results in our laboratory have shown that the 4.4 hr half-life nuclide Br-80m, when incorporated into DNA is radiotoxic, and that both steroidal and non-steroidal estrogens containing this nuclide are taken up by ER+ tissues in animals. Our specific aims are therefore: 1) to evaluate in cell culture and animal models the use of radio-iodinated estrogens for the imaging and treatment of ER+ cancers; 2) to establish the feasibility, quantitative features and application of the Auger electron emission of Br-80m labeled estrogens for treatment of ER+ cancers; 3) to elucidate the molecular effects of Auger electrons emanating from steroid receptor-directed ligands upon the steroid receptor proteins and on the DNA to which the receptors are bound; and to explore other approaches to the use of Auger electron emitting nuclides for therapy. Bromine-80m will be produced by the Se-80 (p,n) reaction and attached to the desired ligands by electrophilic substitution of tributyltin derivatives. Similar reactions with commercially available l-123 will provide the analogous radioiodoligands. Specific binding of the radiohalogenated ligands to ER will be determined by titration assays (Scatchard plots), competitive binding and sedimentation analysis using monoclonal antibodies to the steroid receptors. The specific target tissue uptake will be determined by administration of the radioligands to animals in the absence and presence of unlabeled estrogen, and imaging or assay of tissue content of the nuclide, as appropriate. Radiotoxicity will be assessed in steroid receptor positive and negative cells in vitro and in tumors in animals, and compared with the assayed uptake of ligand by the target and nontarget cells of radiohaloestrogen and ER, respectively. Basic studies will measure the radiolytic effects of receptor-directed ligands on the receptor proteins and on associated DNA in model systems.

本研究的长期目标是建立可行性和 利用俄歇电子的类固醇受体定向治疗的适用性 发射核素共价连接到特异性受体结合配体 来治疗含有适当类固醇激素受体的癌症。 的 提出的方法是基于1）已知的类固醇受体的能力， 与受体配体形成高亲和力复合物， 与细胞核中的DNA区域密切相关，2） 合成保持高亲和力的溴-和碘-配体的能力 对于类固醇受体，3）溴的核素的可用性， 碘通过发射俄歇电子而衰变，以及4）高度 DNA中发射的俄歇电子的有效DNA裂解辐射。 而 内分泌疗法对那些雌激素受体 阳性癌症，如乳腺癌和子宫内膜癌， 只有大约一半的受体阳性癌症患者， 在这种治疗后获得缓解。 某些癌症，如 卵巢癌通常含有雌激素受体（ER）， 内分泌治疗。 当前内分泌治疗的局限性 同意他们要求癌症的生长取决于 激素，而且本质上是细胞抑制性。 另一方面 类固醇受体导向治疗与俄歇电子发射，受体- 结合配体预期仅取决于 细胞核中的受体，并通过引起双链DNA面包， 应该能杀死细胞 我们实验室的初步结果显示 4.4小时半衰期的核素Br-80 m，当掺入DNA时， 放射性毒性，并且含有甾体和非甾体雌激素 这种核素被动物的ER+组织吸收。 我们的具体目标是 因此：1）在细胞培养和动物模型中评估 用于ER+癌症的成像和治疗的放射性碘化雌激素; 2） 建立了一个可行的，定量的特点和应用， Br-80 m标记雌激素治疗ER ~+的俄歇电子发射 癌症; 3）阐明俄歇电子发射的分子效应 从类固醇受体蛋白上的类固醇受体定向配体 以及受体结合的DNA;并探索其他 使用俄歇电子发射核素进行治疗的方法。 溴-80m将通过Se-80（p，n）反应产生并连接到 通过三丁基锡的亲电取代得到所需配体 衍生物. 与市售l-123的类似反应将 提供类似的放射性碘配体。 的特异性结合 ER的放射性卤代配体将通过滴定测定来确定 （斯卡查德图），使用竞争性结合和沉降分析 类固醇受体的单克隆抗体。 特定的靶组织 通过将放射性配体给予动物来测定摄取 在不存在和存在未标记的雌激素的情况下， 核素的组织含量，如适用。 放射性将是 在体外类固醇受体阳性和阴性细胞中以及 肿瘤的动物，并与测定的配体摄取的比较， 放射性卤代雌激素和雌激素受体靶细胞和非靶细胞。 基础研究将测量受体导向的 受体蛋白和模型系统中相关DNA上的配体。