In Vivo EPR Imaging of Redox Status and Thiols in Tumor

描述（由申请人提供）：卵巢癌是美国妇女死亡的第五大原因。本病早期通常无症状，但有很高的恶性潜能。由于缺乏适当的诊断技术，这种疾病通常在晚期才被发现。手术用于减脂，然后化疗作为补充治疗方式。铂基复合物（如顺铂、卡铂）与天然产物（如紫杉醇、多西紫杉醇）联合使用是用于治疗卵巢癌的主要化疗药物。然而，铂基化疗方案成功的一个主要限制是复发肿瘤经常出现耐药性。有证据表明，细胞硫醇水平升高与肿瘤细胞对顺铂敏感性降低有关。因此，一种可靠且无创的测定肿瘤中硫醇水平的方法，应成为卵巢癌临床肿瘤学、药理学和时间治疗的有用辅助手段。本提案的目的是开发和应用电子顺磁共振（EPR）光谱和成像技术来测量肿瘤氧化还原状态，包括体内硫醇水平。EPR技术具有直接和无创检测组织中整体氧化还原以及硫醇氧化还原的独特优势。此外，可靠和准确的体外测量可以在细胞悬浮液和活检组织中进行，易于制备和最少的处理。体外细胞系统和体内小鼠肿瘤模型的初步数据表明，利用EPR光谱可以测量和成像硫醇水平。具体目标是：1。体外EPR技术测定人卵巢癌细胞内硫醇含量的研究2. 体内EPR技术的发展，对小鼠正常组织和肿瘤的氧化还原状态和硫醇进行无创成像；3. 在使用铂类抗肿瘤药物和紫杉烷治疗之前、期间和之后监测卵巢癌细胞中的硫醇水平；4. 人卵巢癌细胞在胸腺裸鼠体内作为实体瘤异种移植物生长时硫醇的体内测量和成像。该结果将有助于更好地了解卵巢癌耐药的发展，并为卵巢癌患者的有效治疗提供有效的诊断。

DESCRIPTION (provided by applicant): Ovarian Cancer is the fifth leading cause of death among women in the United States. Early stages of this disease are usually asymptomatic with high malignant potential. Due to lack of adequate diagnostic techniques, the disease is usually detected at late stages. Surgery is used for debulking followed by chemotherapy as a supplemental treatment modality. Platinum-based complexes (for example, cisplatin, carboplatin) in combination with natural products (e.g. paclitaxel, docetaxel) are the primary chemotherapeutic agents used in the treatment of ovarian cancer. However, a major limitation to the success of the platinum-based chemotherapeutic regimen is the frequent development of drug resistance in the recurrent tumor. Evidences suggest that increased cellular thiol levels are associated with the reduced sensitivity of tumor cells to cisplatin. Therefore, a reliable and noninvasive method to determine the thiol level in the tumor should be a useful adjunct for the clinical oncology, pharmacology and chronotherapy of ovarian cancer. The objective of this proposal is to develop and apply electron paramagnetic resonance (EPR) spectroscopy and imaging techniques to measure tumor redox status, including thiol levels, in vivo. The EPR technique has the unique advantage of direct and noninvasive detection of overall redox as well as thiol redox in tissues. In addition, reliable and accurate in vitro measurements can be performed in cell suspension and biopsy tissues with ease of preparation and minimum processing. Preliminary data on in vitro cellular systems and in vivo murine tumor models show that the thiol levels can be measured and imaged utilizing EPR spectroscopy. The specific aims are: 1. Development of an in vitro EPR technique to perform measurement of intracellular thiols in human ovarian cancer cells; 2. Development of in vivo EPR techniques to perform non-invasive imaging of redox status and thiols of normal tissue and tumor in mice; 3. Monitoring thiol levels in ovarian cancer cells before, during and after treatment with platinum antitumor drugs and taxanes; 4. In vivo measurement and imaging of thiols in human ovarian cancer cells grown as solid tumor xenografts in athymic nude mice. The results will enable a better understanding of the development of drug resistance in ovarian cancer and offer efficient diagnosis for effective treatment of ovarian cancer patients.