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基因变异。这个 大多数癌症驱动基因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还知之甚少。这一关键差距 知识的匮乏阻碍了我们有效管理癌症的能力。人类基因组是 以DNA序列复杂性和高重复DNA含量为特征，但我们缺乏 关于这种复杂基因组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聚合酶相遇 许多难以复制的序列，或DiToR，在导致 复制分叉停顿。如果不能有效导航，DiToRS会导致双链断裂和 基因组不稳定。我们的长期目标是阐明人类基因组的机制 复制和扩展关于肿瘤进化中复制错误的知识。这个项目将 探索人类细胞如何在全基因组范围内进行DiToRs的必要合成，以及 不完全DiToRS复制的遗传后果。我们已建立的跨学科团队 在研究人类基因组的DiToRS区域方面拥有独特的专业知识，并已做出 了解DiToRS复制的重要机制进展。我们最近的研究 暗示dna聚合酶eta(Polη)和kappa(κ)在这一过程中是必不可少的，以及 提出了一种新的范式，在该范式中，POLS、η和κ对复数采用了临界函数 基因组复制。因为这些聚合酶的保真度较低，所以我们假设 要求细胞在DiToRS复制中参与POLSη/κ，复制应激增加复制 肿瘤细胞中的错误。为了验证这一创新假设，我们将使用人类细胞模型和一个 与癌基因激活有关的复制应激的生理来源：dNTP底物耗尽。 目标1将研究DNA聚合酶生物化学并确定关键的复制蛋白 DiToRS复制。Aim 2将研究促进肿瘤所需的关键POLη功能 复制应激对细胞存活的影响及Pol-η对ATR/Chk1抑制剂的影响 有针对性的治疗。目标3将测量非致瘤性和致瘤性的突变 细胞在压力下，并开发新的计算工具来询问癌症基因组 复制错误。我们的机械学研究将通过以下方式提供对机制的关键见解 哪种癌基因激活会导致复制错误，从而驱动肿瘤的发生，并揭示新的 肿瘤进展的生物标志物。从这个项目中获得对突变机制的见解 可用于癌症治疗的精确肿瘤学方法。

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.