DNA ADDUCTS FORMED DURING BRAIN TUMOR THERAPY

每年大约有50,000例新诊断的脑肿瘤。化疗在新诊断和复发性脑肿瘤的治疗中起着重要作用。基于实验室的研究已经确定，DNA烷基化在化疗药物引发细胞死亡的过程中起着关键作用。为了更好地了解脑肿瘤治疗中的这一过程；我们建议测量DNA外展物在脑内肿瘤用烷基化化疗药物治疗的形成，目前正在评估脑肿瘤的治疗。为实现这一目标，我们提出第一个目标。优化解离增强镧系荧光免疫法（DELFIA）定量O6 -甲基脱氧鸟苷（O6 -MedG）的方法。N7 -甲基脱氧鸟苷（N7 - MeG）的水平将通过电化学检测来确定。我们将测量替莫唑胺（TMZ）处理的胸腺大鼠肿瘤U-87MG细胞中形成的O6 -MedG和N7 -MeG的水平。在这些肿瘤中，我们将探讨O6 -MedG和N7-MeG形成水平与给药途径、治疗剂量和药物以及治疗次数之间的关系。肿瘤中形成的这些烷基化产物的水平将与对侧半球和正常组织中形成的水平进行比较。这些方法将为烷基化化疗药物治疗脑肿瘤的临床前分析提供一种独特的方法。目标2。我们将开发针对BCNU形成的dG-dC交联（1- [N1-2； -脱氧胞苷]，2-[N1-2； -脱氧鸟嘌呤]-乙烷）的多克隆抗血清。利用该抗血清，我们将优化DELFIA方法定量dG-dC交联。目的3研究dG-dC交联O6-（2-羟基乙基）脱氧鸟苷（O6- HOEtdG）和N7-（2-羟基乙基）脱氧鸟苷N7- hoetg的形成。U-87MG致胸大鼠肿瘤用BCNU、SarCNU或米托唑胺治疗。对dG-dC交联、O6-HOEtdG和N7-HOEtG的形成进行了定量分析。我们将研究这些烷基化产物的水平与治疗剂、剂量和剂量之间的关系。治疗次数。这些研究将是首次在脑肿瘤模型中研究BCNU衍生DNA外展物的形成。

Each year there are approximately 50,000 newly diagnosed brain tumors. Chemotherapy is established to be important in the treatment of newly diagnosed and recurrent brain tumors. Laboratory based studies have established that DNA alkylation plays a key role in the initiation of cellular death by chemotherapeutic agents. In order to achieve a better understanding of this process in brain tumor therapy; we propose to measure the formation of DNA abducts in intracerebral (ic.) Tumors treated with alkylating chemotherapeutic agents currently being evaluated for the treatment of brain tumors. To achieve this goal we propose to Aim 1. Optimize a dissociation enhanced lanthanide fluoroimmunoassay (DELFIA) method fo the quantitatation of O6 -methyldeoxguanosine (O6 -MedG). The levels of N7 -methyldeoxguanosine (N7 - MeG) will be determined by electrochemical detection. We will measure the levels of O6 -MedG and N7 -MeG formed in U-87MG cells grown as ic. Tumors in athymic rats treated with temozolamide (TMZ). In these tumors, we will investigate the relationships between levels of O6 -MedG and N7-MeG formed and route of administration, treatment dose and agent and number of treatments. The levels of these alkylation products formed in the ic. tumors will be compared with the levels formed in the contralateral hemisphere and in normal tissues. These methodologies will provide ea unique approach for preclinical analysis of alkytating chemotherapeutic agents in treatment of brain tumors. Aim 2. We will develop a poly clonal antiserum to the dG-dC crosslink (1- [N3-2'deoxycytidly], 2-[N1-2; -DEOXYGUANOSYL]-Ethane) formed by BCNU. Using this antiserum, we will optimize a DELFIA method for the quantitation of the dG-dC crosslink. Aim 3 Investigate the formation of the dG-dC crosslink, O6-(2-hydroxy ethyl) deoxyguanosine (O6- HOEtdG) and N7 - (2-hydroxy ethyl) deoxyguanosine N7-HOEtG. Athymic rats bearing U-87MG ic. Tumors will be treated with either BCNU SarCNU or mitozolamide. The formation of dG-dC crosslink, O6-HOEtdG and N7-HOEtG will be quantitated. We will examine the relationships between levels of these alkylation products and treatment agent, dose and. Number of treatment. These studies will be the first to investigate the formation of BCNU derived DNA abducts in a ic. Brain tumor model.