Studies of cancer risk and prevention with a novel DNA damage-detection technique

描述（由申请人提供）：我们的长期目标是预防和治疗癌症。在活细胞中，DNA不断受到损害。保护机制（如DNA修复）使损伤水平保持在较低水平。但仍有无法修复的损坏发生。这是一个问题，因为未修复的损伤可能导致突变，而某些基因的突变会导致癌症。一些报告表明，在DNA修复能力中存在目前未被发现的细微缺陷的个体容易患癌症。不幸的是，检测这些个体目前在技术上具有挑战性，因此，这些个体仍未被诊断出来。我们最近开发了一种检测DNA损伤的新技术。这项技术不仅可以用于测量DNA损伤水平（从而估计癌症风险），还可以用于估计每个人的修复能力。在目前的提案中，我们有两个具体的目的：目的1：确定在对癌症保护至关重要的两个DNA修复途径（碱基切除修复，BER和核苷酸切除修复，NER）中具有主要（纯合突变）和轻微（杂合）遗传缺陷的小鼠以及相应的NER缺陷的人类细胞中，自发DNA损伤是否增加。我们将使用我们的新技术来筛选和量化带有xpc基因的NER缺陷小鼠零（xpc-/-）和杂合子（xpc）以及相应的人类细胞（xpc-/-和xpc）中自发DNA损伤的存在。该研究还将扩展到BER受损的小鼠（oggl-/-和oggl）。目标2：进一步验证和严格测试我们的新技术检测到的DNA损伤类型。为了进一步验证我们的新技术检测到的DNA损伤类型，我们将研究在特定位置含有化学已知损伤的合成DNA寡核苷酸，以及在NER和BER中有缺陷的酵母菌株。最后，我们将使用报道的测定（QPCR）来测量NER-和BER-突变小鼠的自发DNA损伤水平。从这些实验中获得的数据将为我们的技术的定量和定性检测能力提供可靠的验证。我们的研究有潜力利用创新方法提高对癌症病因、危险因素、诊断、预防和治疗的认识。在未来，我们的DNA损伤检测方法的其他几个潜在用途可以预期，包括评估饮食或治疗方法，以降低癌症风险。

DESCRIPTION (provided by applicant): Our long term goal is prevention and treatment of cancer. In living cells DNA is continuously exposed to damage. Protective mechanisms (such as DNA repair) keep the level of damage low. But still unrepaired damage occurs. This is a problem as unrepaired damage may lead to mutations, and mutations in certain genes lead to cancer. Several reports suggest that individuals with currently unrecognized subtle deficits in their DNA repair capacity are prone to cancer. Unfortunately, detecting these individuals is currently technically challenging and, consequently, these individuals remain undiagnosed. We recently developed a novel technique for the detection of DNA damage. This technology may prove useful not only to measure levels of DNA damage (and therefore estimate cancer risk) but also to estimate the repair capacity of each individual. In the current proposal we have two specific aims: Aim 1: To determine if spontaneous DNA damage is increased in mice with major (homozygous mutant) and subtle (heterozygous) genetic defects in two DNA repair pathways crucial for cancer protection (Base Excision Repair, BER, and Nucleotide Excision Repair, NER), and in the corresponding NER deficient human cells. We will use our novel technique to screen and quantify the presence of spontaneous DNA damage in NER defective mice null (xpc-/-) and heterozygous (xpc) for the Xpc gene and in the corresponding human cells (both xpc-/- and xpc). The study will also be extended to mice compromised in BER (oggl-/- and oggl). Aim 2: To further validate and critically test the types of DNA damage detected by our novel technology. To further validate the types of DNA damage detected by our novel technology, we will study synthetic DNA oligonucleotides containing chemically known lesions, at a specific position, as well as yeast strains defective in NER and BER. Finally, we will use a reported assay (QPCR) to measure the levels of spontaneous DNA damage in the NER- and BER- mutant mice. Data derived from these experiments will provide solid validation for the quantitative and qualitative detection capacity of our technology. Our studies have the potential to improve knowledge of the causes, risk factors, diagnosis, prevention and treatment of cancer using innovative methods. In the future, several other potential uses for our DNA damage detection assay can be anticipated, including evaluation of dietary or therapeutic approaches to reduce cancer risk.