Exploiting replication stress for the selective killing of FGFR-dependent cancers

利用复制应激选择性杀死 FGFR 依赖性癌症

• 批准号: 8878498
• 负责人: Naoko Shima
• 金额: $ 16.53万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8878498
• 关键词: Apoptotic; Area; Binding; Breast Cancer Model; Breast Cancer Patient; Breast Epithelial Cells; Cancer Model; Cell Line; Cell Proliferation; Cell Survival; Cell division; Cell physiology; Cells; Chromatin; Complex; DNA; DNA Damage; DNA biosynthesis; Data; Development; Disease; Exhibits; FGFR1 gene; Fibroblast Growth Factor Receptors; Fire - disasters; G1 Phase; Genome; In Vitro; Investigation; Lead; Licensing; MCM2 gene; Malignant Neoplasms; Mammary gland; Mediating; Mouse Mammary Tumor Virus; Mus; Nature; Normal Cell; Oncogenic; Pathway interactions; Patients; Property; Proteins; RNA Interference; Receptor Activation; Receptor Protein-Tyrosine Kinases; Relative (related person); Replication Origin; Resistance development; Role; S Phase; STAT3 gene; Signal Pathway; Speed; Stress; Supporting Cell; System; Testing; Time; Transgenes; angiogenesis; cancer cell; cancer therapy; combinatorial; helicase; in vivo; killings; malignant breast neoplasm; mammalian genome; migration; mouse model; novel; public health relevance; response; targeted treatment; therapeutic target; therapy resistant; tumor progression

 DESCRIPTION (provided by applicant): Replication stress can be defined as any condition in which the number of replication origins, the timing of origin firing, and/or replication fork speed are significantly altered relative to normal S phase. Under these conditions, cells accumulate unresolved replication intermediates, failing to complete DNA replication. Recent studies demonstrate that replication stress is widespread in a variety of cancers; therefore its exploitation for therapies is an exciting new area to explore. To this end, the majority of current investigations focus on the DNA damage response pathways as major therapeutic targets. In this application, we propose dormant origins as a new target to exploit replication stress in cancer, as increasing evidence indicates that cancer cells rely heavily on dormant origins to override replication stress and sustain their proliferation. All replication origins are "licensed by loading of the MCM2-7 proteins onto chromatin during the late M and early G1 phases. In the subsequent S phase, cells use only a small fraction (5~10%) of chromatin-bound MCM2-7 proteins for the assembly of active replicative helicases to unwind DNA and initiate DNA synthesis. The remaining excess MCM2-7 proteins license dormant origins that can act as backups to rescue stalled replication forks and/or compensate for slow fork progression. While such roles of dormant origins are important even in normal S phase, they are used far more frequently under replication stress that increases the number of stalled forks. Possibly reflecting their over-reliance on dormant origins, cancer cells generally show higher levels of MCM2-7 expression as cancer progresses. Given these properties of dormant origins, we hypothesize that reducing their number will contribute to the selective killing of cancer cells exhibiting replication stress. For a reduction of dormant origins, we will use either RNA-interference mediated depletions of the MCM2-7 proteins or the Mcm4chaos3 homozygous background in which the number of dormant origins are reduced to ~50 % of what is observed in wildtype mice. As a cancer model, we will use the in vitro and in vivo systems for inducible FGFR1 (iFGFR1) activation in breast cancer, because our preliminary data demonstrate that iFGFR1 activation causes robust replication stress. As breast cancers with FGFR abnormalities often develop therapeutic resistance, the development of new therapies targeting dormant origins could benefit patients with such diseases. Our specific aims are as follows: 1) Prove that a reduction of dormant origins impairs the completion of DNA replication upon FGFR activation, 2) Test if a reduction of dormant origins blocks iFGFR1-induced cellular proliferation. We will also determine the efficacy of co-targeting dormant origins with pathways that mediate FGFR-induced survival. Novel aspects of this proposal are not only to test the targeting of dormant origins to exploit replication stress, but also to investigate the mechanism by which aberrant activation of FGFR induces replication stress for the development of combined therapies to achieve the specific killing of cancer with FGFR abnormalities.

 描述（应用程序提供）：复制应力可以定义为复制数量，原点触发时间和/或复制叉速度的任何条件 相对于正常S期有显着改变。在这些条件下，细胞积累了未解决的复制中间体，无法完成DNA复制。最近的研究表明，复制应力在各种癌症中都普遍存在。因此，其对疗法的剥削是一个令人兴奋的新领域。为此，大多数当前 研究以DNA损伤反应途径为主要治疗靶标。在此应用中，我们提出休眠起源是利用癌症复制应激的新目标，因为越来越多的证据表明癌细胞严重依赖休眠的起源来超越复制应力并维持其增殖。所有复制起源都是“通过在M和G1早期将MCM2-7蛋白加载到染色质上的许可。在随后的S阶段，细胞仅使用少量（5〜至10％）的MCM2-7蛋白的小部分（5〜10％）来使活性重复型螺旋酶的组装来释放DNA和启动DNA合成元素，并启动DNA合成元素。这可以作为挽救停滞的复制叉的备份和/或补偿较慢的叉子进展 随着癌症的进展，癌细胞对休眠起源过度依赖，通常显示出更高水平的MCM2-7表达。鉴于休眠起源的这些特性，我们假设减少它们的数量将有助于选择性杀死经历复制应力的癌细胞。为了减少休眠起源，我们将使用MCM2-7蛋白的RNA解关介导的部署或MCM4CHAOS3纯合背景，其中休眠起源的数量被降低至野生型小鼠中观察到的物质的〜50％。作为癌症模型，我们将使用体外和体内系统在乳腺癌中进行诱导的FGFR1（IFGFR1）激活，因为我们的初步数据表明IFGFR1激活会导致强大的复制应力。由于患有FGFR异常的乳腺癌通常会产生治疗性抗性，因此靶向休眠起源的新疗法的发展可能使患有此类疾病的患者受益。我们的具体目的如下：1）证明休眠起源的减少会损害FGFR激活后DNA复制的完成，2）测试是否减少休眠起源会阻止IFGFR1诱导的细胞增殖。我们还将确定与介导FGFR诱导的存活率的途径共同靶向休眠起源的效率。该提案的新方面不仅是为了测试休眠起源以利用复制应力的靶向，而且还研究了FGFR异常激活引起复制应力以开发合并治疗的机制，以实现FGFR异常的特异性杀害。