PREDICTING RADIATION RESPONSE BY TUMOR PO2 AND THIOLS

描述：使用个体大鼠体内肿瘤，详细分析将 放射治疗抵抗力和 新开发的缺氧、硫醇、细胞呼吸和 肿瘤血流 缺氧和硫醇会增加辐射 体外细胞的抗性，独立于所有其他已知的原因， 治疗抵抗 我们的中心假设是缺氧和硫醇起作用 以协同的方式增加肿瘤细胞的辐射抗性， in vivo. 因此，这些化学因素的测量应该预测 单个肿瘤的辐射抗性。 各种具体假设将 测试： I）放射治疗抵抗性的可靠估计直接取决于 硫醇浓度和氧浓度成反比。 氧 浓度将通过测量代谢产生的加合物来测定， EF 5，2-硝基咪唑，使用单克隆抗体。 谷胱甘肽和 半胱氨酸浓度将通过HPLC测定， 侦测 两种试验均将使用临床相关活检。 辐射 通过在体内照射肿瘤，然后接种细胞， 用于克隆形成。 II）低氧浓度是血流减少的直接结果。 将在微观和宏观水平上进行血流测量。 前者将通过Hoechst 33342染料的分布进行评估， 其他方法。 后者将通过直接流动和激光进行评估， 超声多普勒技术。 III）非侵入性超声多普勒成像可以选择肿瘤最多的区域 可能含有缺氧细胞 虽然基于多普勒的方法不能 提供血流量的绝对测量，他们可以选择 血流相对较低的肿瘤区域。 这将使新的活检 最小化肿瘤内异质性引起的问题的策略 低氧分布。 IV）用于成像的非侵入性方法可以提供以下方面的定量分析： 组织缺氧 在我们目前的研究中使用的2-硝基咪唑药物可以 用于磁共振波谱和成像（MRS/MRI）。 的 生物分布和肿瘤：组织比将作为以下因素的函数进行研究： 药物浓度。 将通过比较进行光谱学验证 NMR值与实际药物加合物分布，通过 抗体和免疫组织化学。

DESCRIPTION: Using individual rat tumors in vivo, a detailed analysis will be made of the relationship between radiation therapy resistance and newly-developed diagnostic assays for hypoxia, thiols, cell respiration and tumor blood flow. Hypoxia and thiols are known to increase the radiation resistance of cells in vitro, independently of all other known causes of therapy resistance. Our central hypothesis is that hypoxia and thiols act in a synergistic manner to increase the radiation resistance of tumor cells in vivo. Thus, measurements of these chemical factors should predict the radiation resistance of individual tumors. Various specific hypotheses will be tested: I) Reliable estimates of radiation therapy resistance depend directly on the thiol concentration and inversely on the oxygen concentration. Oxygen concentrations will be assayed by measuring metabolism- produced adducts of EF5, a 2-nitroimidazole, using monoclonal antibodies. Glutathione and cysteine concentrations will be assayed by HPLC with electrochemical detection. Both assays will use clinically relevant biopsies. Radiation response will be measured by irradiating tumors in vivo, then plating cells from the tumors for clonogenicity. II) Low oxygen concentrations are a direct result of diminished blood flow. Blood-flow measurements will be made at a microscopic and macroscopic level. The former will be assessed by the distribution of Hoechst 33342 dye and other methods. The latter will be assessed by direct flow and laser and ultrasound Doppler techniques. III) Non-invasive ultrasound Doppler imaging can select areas of tumors most likely to contain hypoxic cells. Although Doppler-based methods cannot provide absolute measures of blood flow they may be able to select for regions of tumors with relatively low flow. This would enable a new biopsy strategy to minimize problems caused by intratumoral heterogeneity of the distribution of hypoxia. IV) Non-invasive methods for imaging can provide quantitative analysis of tissue hypoxia. The 2-nitroimidazole drugs used in our current studies can be used for magnetic resonance spectroscopy and imaging (MRS/MRI). The biodistribution and tumor:tissue ratios will be studied as a function of drug concentration. Verification of spectroscopy will be made by comparing the NMR values with the actual drug-adduct distribution determined by antibodies and immunohistochemistry.