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

基本信息

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
项目类别：
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

项目摘要

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（由申请人提供）：复制压力可以定义为任何条件，其中复制起点的数量、起点激发的时间和/或复制叉速度相对于正常的 S 期，细胞会积累未解决的复制中间体，从而无法完成 DNA 复制。为此，当前多数人进行了探索。研究重点是将DNA损伤反应途径作为主要治疗靶点。在本申请中，我们提出将休眠起源作为利用癌症复制压力的新靶点，因为越来越多的证据表明癌细胞严重依赖休眠起源来克服复制压力并维持。它们的增殖都是通过在 M 晚期和 G1 早期将 MCM2-7 蛋白加载到染色质上来获得的。在随后的 S 期中，细胞仅使用一小部分 (5~10%) 的染色质结合。 MCM2-7 蛋白用于组装活性复制解旋酶以解旋 DNA 并启动 DNA 合成，剩余的多余 MCM2-7 蛋白许可休眠起源，可以作为备份来拯救停滞的复制叉和/或补偿缓慢的复制叉进展。即使在正常的 S 期，休眠起源的作用也很重要，在复制压力下，它们的使用频率要高得多，这可能会增加停滞分叉的数量。由于它们过度依赖休眠起源，随着癌症的进展，癌细胞通常会表现出更高水平的 MCM2-7 表达。鉴于休眠起源的这些特性，我们认为减少它们的数量将有助于选择性杀死表现出复制应激的癌细胞。为了减少休眠起源，我们将使用 RNA 干扰介导的 MCM2-7 蛋白缺失或 Mcm4chaos3 纯合背景，其中休眠起源的数量减少至约 50%作为癌症模型，我们将使用体外和体内系统来诱导乳腺癌中的 FGFR1 (iFGFR1) 激活，因为我们的初步数据表明，iFGFR1 激活会导致具有 FGFR 的乳腺癌产生强烈的复制应激。异常通常会产生治疗耐药性，针对休眠起源的新疗法的开发可以使患有此类疾病的患者受益：1）证明休眠起源的减少会损害 DNA 复制的完成。 FGFR 激活，2) 测试休眠起源的减少是否会阻止 iFGFR1 诱导的细胞增殖。我们还将确定共同靶向休眠起源与介导 FGFR 诱导的存活的途径的功效。靶向休眠起源以利用复制应激，同时还研究 FGFR 异常激活诱导复制应激的机制，以开发联合疗法，以实现特异性杀死 FGFR 异常的癌症。