DNA Damaging Signaling in Human Cancer Cells

描述（由申请人提供）：许多广泛使用的抗癌药物具有遗传毒性，并激活细胞DNA损伤途径。这些信号转导通路的缺陷是结直肠癌、乳腺癌和其他常见癌的常见特征，也可以在癌症易感个体中遗传。因此，DNA损伤信号传导、致癌作用和癌症治疗之间关系的研究应该为这些领域的每一个领域提供重要的见解。该项目的目的是开发一个模型系统，用于对人类癌细胞中DNA损伤反应的三个关键调节因子进行遗传评估。 目标1. DNA损伤反应中人CHK2激酶的分析。最近，人们对CHK2及其在细胞周期调控和癌症易感性中的作用有了大量的了解。这种激酶如何正常调节细胞周期的确切细节，以及它如何作为肿瘤抑制剂发挥作用仍然存在争议。这一目的是了解CHK2如何在细胞周期的离散阶段指导受损癌细胞的停滞，以及CHK2功能的丧失如何导致遗传不稳定。 目标2. DNA损伤反应中人CHK1活化的分析。CHK1编码典型的细胞周期检查点调节因子，因此是基于DNA损伤的治疗的重要靶标。该目的旨在研究CHK1活化的影响，CHK1在未受攻击的癌细胞中的作用以及CHK1和CHK2肿瘤抑制因子的重叠功能。 目标3. DNA损伤信号传导中的NBS1突变分析。在具有奈梅亨断裂综合征的癌症易感个体中发生突变，NBS1基因代表了人类癌症与DNA损伤信号转导之间的重要联系。该目的是在人类癌细胞系中建立致病性NBS1突变的模型。这样的模型系统将提供一个独特的机会来研究NBS1在细胞周期阻滞，修复染色体断裂和治疗敏感性中的功能。 上述研究的结合将为深入了解DNA损伤信号转导通路的功能及其在人类癌症中的功能障碍提供相当大的帮助。

DESCRIPTION (provided by applicant): Many widely used anticancer agents are genotoxic and activate cellular DNA damage pathways. Defects in these signal transduction pathways are frequent features of colorectal, breast, and other common carcinomas, and can also be inherited in cancer-prone individuals. Studies of the relationship between DNA damage signaling, carcinogenesis, and cancer therapy should therefore provide important insights into each of these areas. The aims of this project are to develop a model system for the genetic assessment of three key regulators of the DNA damage response in human cancer cells. Aim 1. Analysis of human CHK2 kinase in DNA damage responses. Recently a great deal has been learned about CHK2 and its roles in cell cycle regulation and cancer predisposition. The precise details of how this kinase normally regulates the cell cycle, and how it functions as a tumor suppressor remain controversial. This aim is to understand how CHK2 can direct the arrest of damaged cancer cells during discrete phases of the cell cycle, and how loss of CHK2 function might lead to genetic instability. Aim 2. Analysis of human CHK1 activation in DNA damage responses. CHK1 encodes a canonical cell cycle checkpoint regulator and therefore an important target of DNA damage based therapy. This Aim is intended to study the effects of CHK1 activation, the role of CHK1 in unchallenged cancer cells and the overlapping functions of CHK1 and the CHK2 tumor suppressor. Aim 3. Analysis of NBS1 mutation in DNA damage signaling. Mutated in cancer prone individuals with the Nijmegen Breakage Syndrome, the NBS1 gene represents an important link between human cancer and the transduction of DNA damage signals. This Aim is to model the pathogenic NBS1 mutations in a human cancer cell line. Such a model system will provide a unique opportunity to study NBS1 function in cell cycle arrest, repair of chromosome breaks and therapeutic sensitivity. The combination of the above studies should provide considerable insight into functions of DNA damage signal transduction pathways and their dysfunction in human cancers.