Pro-tumorigenic functions of human DNA polymerases eta and kappa during genome duplication under physiological replication stress conditions

肿瘤细胞会发生突变，产生适应压力环境的遗传变异。的 大多数癌症驱动突变可能是由复制错误引起的，但来源和 人类肿瘤中这种复制错误的机制知之甚少。这一关键差距 阻碍了我们有效控制癌症的能力。人类基因组是 具有DNA序列复杂性和高重复DNA含量的特点，但我们缺乏 这种复杂的基因组是如何复制的详细机制，限制了我们对 促进癌症发展的内源性过程。DNA聚合酶遭遇 重复区域内的许多难以复制的序列，或DiToRS， 复制分叉正在停止。如果不能有效导航，DiToRS会导致双链断裂， 基因组不稳定性我们的长期目标是阐明人类基因组的机制 复制和扩大知识的复制错误在肿瘤的演变。该项目将 发现人类细胞如何进行DiToRS全基因组的基本合成，以及 不完全DiToRS复制的遗传后果。我们的跨学科团队 在研究人类基因组的DiToRS区域方面拥有独特的专业知识， 对理解DiToRS复制的重要机制进展。我们最近的研究 暗示DNA聚合酶eta（Pol η）和kappa（κ）是该过程所必需的， 提出了一种新的范式，其中Pol η和κ采用了复杂的临界函数， 基因组复制因为这些聚合酶具有低保真度，我们假设， 需要细胞在DiToRS复制中接合Pos η/κ，复制应激增加复制 肿瘤细胞的错误。为了验证这一创新的假设，我们将使用人类细胞模型和一个 与癌基因激活相关的复制应激的生理来源：dNTP底物耗竭。 目的1将研究DNA聚合酶的生物化学，并确定所需的关键复制蛋白质， DiToRS复制。目的2将研究促进肿瘤发生所需的关键Pol η功能 在复制应激存在下的细胞存活，以及Pol η对ATR/Chk 1抑制剂的影响 靶向治疗。目标3将测量非致瘤性和致瘤性中出现的突变。 细胞的压力，并开发新的计算工具来询问癌症基因组， 复制错误。我们的机制研究将提供关键的见解的机制， 其中癌基因激活导致复制错误，驱动肿瘤发生，并揭示新的 肿瘤进展的生物标志物。从该项目中获得的对突变机制的见解 可以在癌症治疗的精确肿瘤学方法中利用。

Tumor cells make mutations, creating genetic variants that adapt to stressful environments. The majority of cancer driver mutations may be caused by replication errors, but the sources and mechanisms of such replication errors in human tumors are poorly understood. This critical gap in knowledge hinders our ability to effectively manage cancer. The human genome is characterized by DNA sequence complexity and high repetitive DNA content, but we lack detailed mechanisms as to how this complex genome is replicated, limiting our understanding of the endogenous processes that promote cancer development. DNA polymerases encounter many Difficult-To-Replicate Sequences, or DiToRS, within repetitive regions that cause replication fork stalling. If not navigated efficiently, DiToRS lead to double strand breaks and genome instability. Our long-term goals are to illuminate mechanisms of human genome replication and expand knowledge of replication errors in tumor evolution. This project will discover how human cells carry out essential synthesis of DiToRS genome-wide, and the genetic consequences of incomplete DiToRS replication. Our established interdisciplinary team has unique expertise in studying DiToRS regions of the human genome, and has made important mechanistic advances towards understanding DiToRS replication. Our recent studies implicate DNA polymerases eta (Pol η) and kappa (κ) as being essential for this process, and advance a new paradigm in which Pols η and κ have adopted critical functions for complex genome replication. Because these polymerases have low fidelity, we hypothesize that by requiring cells to engage Pols η/κ in DiToRS replication, replication stress increases replication errors in tumor cells. To test this innovative hypothesis, we will use human cell models and a physiologic source of replication stress linked to oncogene activation: dNTP substrate depletion. Aim 1 will study DNA polymerase biochemistry and identify key replication proteins required for DiToRS replication. Aim 2 will investigate the critical Pol η functions required to promote tumor cell survival in the presence of replication stress, and the impact of Pol η on ATR/Chk1 inhibitor targeted therapies. Aim 3 will measure mutations arising in non-tumorigenic and tumorigenic cells under stress, and develop new computational tools to interrogate cancer genomes for replication errors. Our mechanistic studies will provide key insights into the mechanisms by which oncogene activation results in replication errors that drive tumorigenesis, and reveal new biomarkers of tumor progression. Insights into mutational mechanisms gained from this project can be leveraged in precision oncology approaches to cancer therapy.