HORMONAL MODIFICATIONS OF RADIATION INDUCED MUTAGENESIS

辐射诱变的荷尔蒙改变

• 批准号: 2114514
• 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 1997-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2114514
• 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.

说明(申请人的说明)诱变是 癌症。航天飞机载体系统已经成功地证明了 紫外线辐射(即阳光)引起的特定DNA损伤 可以在皮肤细胞中产生对癌症诱导至关重要的突变。 电离辐射暴露是众所周知的导致乳腺癌的原因，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损伤的突变潜力 已知细胞内受环境因素的调节，如 生理压力和药物。然而，荷尔蒙的潜力( 乳腺细胞新陈代谢的主要调节剂)来改变 乳腺细胞尚不清楚。动物研究表明，荷尔蒙可以 影响辐射诱变，因为辐射的时机 在发情周期或怀孕期间是一个重要的 辐射诱发大鼠乳腺癌发病率的决定因素。 这是一个用来评估荷尔蒙对 电离辐射诱发的乳腺细胞突变。我们的方法 将是测量激素治疗和/或放射治疗中的突变- 使用穿梭载体在体外处理乳腺细胞。穿梭载体 系统是通用的，因为它们可以用来测量 DNA损伤在不同类型细胞中的诱变潜力，或 同一细胞在不同环境条件下的突变 (例如，激素或放射治疗)。DNA在体外会受到损伤 使用放射或拟放射药物，然后将其导入 乳腺细胞，受损的DNA将在那里 由细胞DNA修复酶代谢处理。DNA将会 然后被回收并进行突变检测。因为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将 改变辐射产生的突变的数量和类型。 这一信息可能提示DNA修复机制或转导 对荷尔蒙有反应的途径，可能会提示 抑制或预防辐射诱发的乳腺癌。近期 我们实验室的结果表明，辐射诱变可能 发生于哺乳动物细胞的两条主要的“容易出错”的DNA修复途径 可以使用穿梭载体质粒DNA进行独立探测 有单链或双链断裂。我们将使用这样的质粒 为了确定这些通路在乳腺细胞中的潜在作用 诱变。这项拟议的研究是一项探索性的试验 这个项目有望发展成一个未来的、更全面的 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的一个优先领域。在……下面 在这一领域，它还包括三个研究主题，分别是 对RFA表示兴趣：辐射、激素和 基因与环境的相互作用。此外，根据以下目标 RFA，首席调查员，虽然建立得很好，但 这是乳腺癌研究领域的新发现。