Single-molecule studies of BRCA1-BACH1 mechanism in genomic integrity

 描述(申请人提供)：DNA损伤反应(DDR)途径在维持基因组稳定和预防癌症方面发挥着关键作用。通过以下方式破坏这条通路 BRCA1或其结合伙伴BACH1的突变会增加患者的癌症发病率，这表明这些蛋白质对于预防肿瘤发生是必不可少的。BACH1和BRCA1对于建立DNA损伤检查点、通过同源重组修复双链断裂和维持基因组稳定性是必不可少的。虽然BRCA1临床突变破坏了BACH1结合，但BRCA1结合如何影响BACH1功能并最终影响癌症抑制尚不清楚。我们建议的目标是在高度协作的跨学科研究计划中，使用显著创新的实验工具来研究乳腺癌的分子基础。具体地说，罗森伯格博士的实验室将领导单分子实验方法，包括分析和技术开发以及数据分析，而坎托博士的实验室将提供样本和设计分子靶标。坎托博士是BRCA1研究和BRCA1-BACH1系统表征方面的专家领导者。Rothenberg实验室和Cantor实验室之间正在进行的协同作用以及PIS的专业知识是拟议研究的理想选择。我们将共同开发强大的单分子成像技术，能够解开使用其他方法无法获得的重要细节。这些技术在概念上是开创性的，将为这里提出的生物学问题提供新的信息。这项提议将检验BRCA1调节BACH1DNA解旋酶活性以修复DNA和抑制肿瘤的新假设。具体地说，我们将研究BRCA1是否调节BACH1的定位和/或直接调节其解旋酶活性。重要的是，我们拟议的研究将剖析BRCA1与BACH1结合是如何与DNA修复和乳腺癌抑制有关的。我们将直接测试BRCA1/BACH1复合体的丢失是否会扰乱正常的细胞DNA损伤反应和修复。分析BACH1患者的突变将阐明导致癌症形成的遗传事件。揭示BRCA1与BACH1结合是如何与肿瘤抑制有关的，可能会促进合理设计的治疗方法的产生，以对抗疾病。例如，有可能通过引入BRCA1模拟物来概括BRCA1如何调节BACH1。此外，癌症研究中的许多努力都集中在将细胞从“DNA交联型”转变为“DNA交联型”。如果BRCA1调节BACH1解旋酶活性以影响DNA损伤信号，这种BRCA1/BACH1相互作用的中断可能成为使细胞对化疗药物敏感的工具。如果是这样的话，这些蛋白质将是开发克服乳腺癌DNA交联性耐药药物的极佳靶点。事实上，我们研究中使用的试剂可能是开发此类药物的基础。

 DESCRIPTION (provided by applicant): The DNA damage response (DDR) pathway plays a critical role in maintaining genomic stability and preventing cancer. Disruption of this pathway by mutations in BRCA1 or its binding partner BACH1 increases cancer incidence in patients, suggesting that these proteins are essential for prevention of tumorigenesis. BACH1 and BRCA1 are essential for establishing a DNA damage checkpoint, repair of double strand breaks by homologous recombination, and maintenance of genome stability. Although BRCA1 clinical mutations disrupt BACH1 binding, it is unclear how BRCA1 binding affects BACH1 function and ultimately cancer suppression. The objective of our proposal is to study the molecular basis of breast cancer using significantly innovative experimental tools in a highly collaborative interdisciplinary research program. Specifically, the lab of Dr. Rothenberg will lead the single-molecule experimental approaches, including assay and technique development and data analysis, while the lab of Dr. Cantor, an expert leader in BRCA1 studies and characterization of the BRCA1-BACH1 system, will provide samples and design the molecular targets. The ongoing synergy between the Rothenberg and Cantor laboratories and expertise of the PIs is ideal for the proposed studies. Together, we will develop powerful single-molecule imaging techniques capable of unraveling significant details that cannot be obtained using other methods. These techniques are conceptually groundbreaking and will provide new information on the biological questions presented here. This proposal will test the novel hypothesis that BRCA1 regulates BACH1 DNA helicase activity for DNA repair and tumor suppression. Specifically, we will examine whether BRCA1 regulates BACH1 localization and/or directly modulates its helicase activity. Importantly, our proposed research will dissect how BRCA1 binding to BACH1 is linked with DNA repair and breast cancer suppression. We will directly test whether loss of the BRCA1/BACH1 complex disrupts normal cellular DNA damage response and repair. Analyzing BACH1 patient mutations will elucidate the genetic events that drive cancer formation. Uncovering how BRCA1 binding to BACH1 is linked to tumor suppression could foster the generation of rationally designed therapies to combat disease. For example, it may be possible to recapitulate how BRCA1 regulates BACH1 by introduction of a BRCA1 mimetic. Furthermore, many efforts in cancer research are centered on switching cells from "DNA crosslink-resistant" to "DNA crosslink-sensitive". If BRCA1 regulates BACH1 helicase activity to effect DNA damage signaling, disruption of this BRCA1/BACH1 interaction could serve as a tool to render cells sensitive to chemotherapeutic drugs. If so, these proteins will represent excellent targets for developing drugs to overcome DNA crosslink resistance in breast cancers. In fact, the reagents used in our studies may be the basis for developing such drugs.