PREDICTING RADIATION RESPONSE BY TUMOR PO2 AND THIOLS

描述：使用体内单个大鼠肿瘤，详细分析将 要了解放射治疗抵抗与 新开发的低氧、硫醇、细胞呼吸和 肿瘤血流量。众所周知，低氧和硫醇会增加辐射 细胞在体外的抵抗力，与所有其他已知的原因无关 治疗抵抗。我们的中心假设是低氧和硫醇起作用 以协同的方式增加肿瘤细胞的抗辐射能力 在活体内。因此，对这些化学因素的测量应该可以预测 个体肿瘤的辐射抗性。各种具体的假设将 被测试： I)对放射治疗抵抗力的可靠估计直接取决于 硫醇浓度与氧浓度成反比。氧 浓度将通过测量新陈代谢产生的加合物进行分析 EF5，一种2-硝基咪唑，使用单抗。谷胱甘肽和 半胱氨酸浓度将用高效液相色谱-电化学法测定 侦测。这两种分析都将使用临床相关的活检组织。辐射 反应将通过照射体内的肿瘤，然后培养细胞来衡量 从肿瘤中分离出克隆性。 Ii)低氧浓度是血流量减少的直接结果。 血液流量的测量将在微观和宏观层面上进行。 前者将通过Hoechst 33342染料和 其他方法。后者将通过直流法和激光法进行评估，并 超声多普勒技术。 3)无创超声多普勒成像能最大限度地确定肿瘤部位 可能含有缺氧细胞。尽管基于多普勒的方法不能 提供他们可以选择的血流量的绝对测量 血流相对较低的肿瘤区域。这将使新的活检成为可能 最大限度减少由肿瘤内异质性引起的问题的策略 缺氧的分布情况。 四)非侵入性成像方法可提供对 组织缺氧。我们目前研究中使用的2-硝基咪唑类药物可以 用于磁共振波谱和成像(MRS/MRI)。这个 生物分布和肿瘤：组织比率将作为以下因素的函数进行研究 药物浓度。光谱学的验证将通过对比进行 实际药物加合物分布的核磁共振值由 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.