HORMONAL MODIFICATIONS OF RADIATION INDUCED MUTAGENESIS

辐射诱变的荷尔蒙改变

• 批准号: 2009728
• 负责人: TIMOTHY J JORGENSEN
• 金额: $ 8.05万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-30 至 1998-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2009728
• 关键词: DNA damage; DNA repair; breast neoplasms; gene mutation; hormone regulation /control mechanism; hormone related neoplasm /cancer; ionizing radiation; mammary gland; radiation related neoplasm /cancer; tissue /cell culture; transfection

DESCRIPTION (Applicant's Description) Mutagenesis is a precursor to cancer. Shuttle vector systems have successfully demonstrated that specific DNA lesions resulting from ultraviolet radiation (i.e. sunlight) can produce mutations important to cancer induction in skin cells. Ionizing radiation exposure is a well known cause of breast cancer, yet similar shuttle vector studies with ionizing radiation and mammary cells have not been done. Additionally, the mutagenic potential of DNA damage in cells is known to be modulated by environment factors, such physiological stress and drugs. Yet, the potential of hormones (the major modulators of mammary cell metabolism) to modify mutagenesis in mammary cells is not known. Animal studies suggest that hormones can influence radiation mutagenesis, since the timing of irradiation during the estrous cycle or during pregnancy is a significant determinant of incidence of radiation-induced breast cancer in rats. This is a application to assess the influence of hormones on ionizing-radiation-induced mutagenesis in mammary cells. Our approach will be to measure mutagenesis in hormonally-treated and/or radiation- treated mammary cells in vitro, using shuttle vectors. Shuttle vector systems are versatile in that they can be used to measure either the mutagenic potential of DNA lesions in different types of cells, or mutations in the same cells under different environmental conditions (eg. hormone- or radiation-treated). DNA will be damaged in vitro with radiation or radiomimetic drugs and then transfected into mammary cell hosts, where the damaged DNA will be metabolically processed by cellular DNA repair enzymes. The DNA will then be recovered and assayed for mutations. Since DNA synthesis, repair, and regulatory enzymes are known to be affected by physiological states, our hypothesis is that hormonal treatment will alter both the quantity and type of mutations produced by radiation. This information may suggest DNA repair mechanisms or transduction pathways that are hormonally responsive and may suggest ways of inhibiting or preventing radiation-induced breast cancer. Recent results, from our laboratory, suggest that radiation mutagenesis may occur via two major "error-prone" DNA repair pathways of mammalian cells that can be independently probed using shuttle vector plasmid DNA with either single- or double-strand breaks. We will use such plasmids to determine the potential roles of these pathways in mammary cell mutagenesis. The proposed study represents an exploratory pilot project that will hopefully develop into a future, more comprehensive, breast cancer research project. It directly addresses problems of breast cancer etiology, which is a priority area of the RFA. Under this area, it also incorporates three research topics that are of expressed interest to the RFA: effects of radiation, hormones, and gene- environment interactions. Also, in accordance with the goals of the RFA, the Principal Investigator, although well established, is new to the field of breast cancer research.

描述（申请人的描述）诱变是 癌症。 航天飞机矢量系统已成功证明 紫外线（即阳光）导致的特定 DNA 损伤 可以产生对皮肤细胞癌症诱导很重要的突变。 电离辐射暴露是乳腺癌的众所周知的原因，但 电离辐射和乳腺细胞的类似穿梭载体研究 还没有完成。此外，DNA 损伤的潜在致突变性 众所周知，细胞中的细胞受到环境因素的调节，例如 生理压力和药物。然而，荷尔蒙的潜力（ 乳腺细胞代谢的主要调节剂）来改变突变 乳腺细胞尚不清楚。动物研究表明，激素可以 影响辐射诱变，因为辐射时间 在发情周期或怀孕期间是一个重要的 大鼠辐射诱发乳腺癌发病率的决定因素。 这是一个评估激素影响的应用程序 乳腺细胞中电离辐射诱导的突变。我们的方法 将测量激素处理和/或辐射的诱变 使用穿梭载体在体外处理乳腺细胞。穿梭矢量 系统用途广泛，可用于测量 不同类型细胞中 DNA 损伤的潜在致突变性，或 同一细胞在不同环境条件下发生突变 （例如激素或放射治疗）。 DNA在体外会被破坏 用放射线或拟放射药物，然后转染 乳腺细胞宿主，受损的 DNA 将在那里 由细胞 DNA 修复酶进行代谢加工。 DNA 将 然后被回收并检测突变。 由于DNA 已知合成、修复和调节酶会受到影响 根据生理状态，我们的假设是激素治疗会 改变辐射产生的突变的数量和类型。 该信息可能表明 DNA 修复机制或转导 对激素有反应的途径，可能会建议 抑制或预防辐射诱发的乳腺癌。最近的 我们实验室的结果表明，辐射诱变可能 通过哺乳动物细胞的两个主要“容易出​​错”的 DNA 修复途径发生 可以使用穿梭载体质粒 DNA 独立探测 具有单链或双链断裂。 我们将使用这样的质粒 确定这些途径在乳腺细胞中的潜在作用 诱变。 拟议的研究是一项探索性试点 项目有望发展成为未来更全面、 乳腺癌研究项目。 它直接解决了以下问题 乳腺癌病因学，这是 RFA 的优先领域。在下面 该领域还包含三个研究主题 对 RFA 表示感兴趣：辐射、激素和 基因-环境相互作用。另外，根据目标 RFA，首席研究员，虽然已经很完善，但 乳腺癌研究领域的新手。