Thymineless stress, DNA repair and recombination

无胸腺嘧啶应激、DNA 修复和重组

• 批准号: 6937205
• 负责人: MICHAEL D. WYATT
• 金额: $ 26.12万
• 依托单位: UNIVERSITY OF SOUTH CAROLINA AT COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6937205
• 关键词: DNA damage; DNA directed DNA polymerase; antineoplastics; apoptosis; cell growth regulation; cell line; chromatin; chromosome aberrations; electrophoresis; enzyme induction /repression; enzyme inhibitors; gene mutation; genetic recombination; intermolecular interaction; neoplastic cell; nucleic acid chemical synthesis; nucleotide metabolism; protein structure function; southern blotting; thymidine monophosphate; thymidylate synthase; time resolved data; uracil; uridine triphosphate; western blottings

DESCRIPTION (provided by applicant): The long-term objectives of this application are to better understand the DNA damage mechanisms that influence the response of normal cells and cancer cells to chemotherapy. Thymidylate deprivation is induced by inhibition of thymidylate synthase (TS) and is a therapeutic effect of several classes of antineoplastic drugs, such as 5-fluorouracil and raltitrexed (Tomudex). Inhibition of TS leads to loss of TTP necessary for replication. Thymidylate deprivation leads to cell death, unlike the cytostatic effects associated with other nutritional deficiencies. Despite decades of study, the precise mechanism by which TS inhibition causes death remains unclear. Some cellular responses to TS inhibition include an alteration in deoxynucleotide pools including an increase in dUTP levels, uracil incorporation into DNA, cell cycle arrest during S-phase, and induction of DNA strand breaks, likely at sites of replication. A key unanswered question remains "what is the specific nature of the damage during thymidylate deprivation that results in cell death?" The hypothesis to be tested in this project is that activation and progression of base excision repair (BER) under conditions of thymidylate deprivation lead to aberrant recombination and, eventually, apoptosis. The Specific Aims of this project are: Aim 1: To determine whether the initiation and progression of BER during thymidylate deprivation contributes to cell death. Aim 2: To determine the fate of BER intermediates during thymidylate deprivation. Aim 3: To determine whether chromosomal recombination is induced during thymidylate deprivation and to investigate the influence of BER on recombination occurring during thymidylate deprivation. Because BER and recombination normally contribute to genome stability, these questions have an added significance when current cancer therapies can themselves induce DNA damage.

描述（由申请人提供）：本应用的长期目标是更好地了解影响正常细胞和癌细胞对化学疗法反应的DNA损伤机制。通过抑制胸苷酸合酶（TS）诱导胸苷酸剥夺，是几类抗肿瘤药物的治疗作用，例如5-氟尿嘧啶和raltitrexed（Tomudex）。 TS的抑制会导致复制所需的TTP丢失。与其他营养缺乏症相关的细胞抑制作用不同，胸苷酸剥夺会导致细胞死亡。尽管进行了数十年的研究，但TS抑制导致死亡的确切机制仍不清楚。对TS抑制作用的一些细胞反应包括脱氧核苷酸池的改变，包括DUTP水平升高，尿嘧啶掺入DNA中，S阶段的细胞周期停滞以及诱导DNA链断裂，可能在复制位置。一个关键的未解决的问题仍然存在：“在胸甲酯剥夺过程中损害导致细胞死亡的特定性质是什么？”在该项目中要检验的假设是，在胸苷酸剥夺条件下，基础切除修复（BER）的激活和进展导致异常重组，最终导致凋亡。该项目的具体目的是：目标1：确定在胸苷酸剥夺过程中BER的起始和进展是否有助于细胞死亡。目的2：确定胸甲酯剥夺期间BER中间体的命运。目标3：确定在胸腺甲基剥落期间是否诱导染色体重组，并研究BER对胸苷酸剥夺期间重组的影响。由于BER和重组通常会导致基因组稳定性，因此当当前的癌症疗法本身会诱导DNA损伤时，这些问题具有更大的意义。