Molecular origins and impact of APOBEC3 mutagenesis in cancer

项目总结 突变是外源和内源过程的结果，这些过程留下了特有的印记或 基因组上的签名。对这些突变特征的系统分析导致了&gt；50的鉴定 人类癌症基因组中不同类型的单碱基替换(SBS)。揭示个体的起源 签名对于理解癌症病因学至关重要，对癌症预防和治疗具有潜在意义。 心理治疗。癌症中最常见的两个突变信号，称为SBS2和SBS13，存在于 78%的癌症类型和56%的癌症基因组，尤其是在乳腺癌、膀胱癌和 肺癌。SBS2和SBS13被认为是由内源性APOBEC3(A3)酶引起的， 它以病毒和逆转录元件的单链DNA和RNA为靶标，作为天然免疫防御的一部分。相关性 在A3表达、A3偏好背景下的驱动基因突变和临床结果之间的关系表明，A3 突变可能在肿瘤的病因学和进化中发挥重要作用。因此，有很强的理由 了解A3活性的机制。然而，依赖工程模型系统和相关 数据导致A3酶、癌症突变和癌症病因学之间的联系很差。 明白了。我们已经鉴定出具有内源性A3突变的人类癌细胞系，并开发出一种 使我们能够量化单个A3成员对突变的贡献的工作流程。在此，我们建议 利用此工作流程实现以下目标：1)确定癌症类型中的A3突变体酶 A3的诱变很普遍，并找到了它们活性的生物标志物；2)研究了A3的调节机制 3)确定A3突变在耐药和转移中的功能相关性。 Aim 1将扩展我们对具有活性A3突变的人类癌细胞的特征，以确定A3 乳腺癌、膀胱癌和肺癌中的突变者。同时，我们将直接评估未知的特异性和 测定单个A3酶活性的灵敏度。这些实验可能进一步证实 推测大量癌症突变的A3病因学并量化个体A3的贡献 酶，从而将它们指定为治疗追求的假定靶点。AIM 2以我们的初步数据为基础 研究已提出的A3诱变调节剂。这些实验有可能扩大 治疗机会的范围集中在癌细胞的进化上。目标3将评估A3和A3之间的联系 酶与乳腺癌、膀胱癌和肺癌细胞株的治疗耐药和转移。这些实验 将测试来自多维关联的预测，即3-突变是一个疾病修正过程 这一点可以在癌症进化的不同阶段用于治疗。总而言之，这些研究将 确定高度流行的突变过程的病因，并确定策略以获得更持久的 靶向治疗和抑制转移的临床益处。

PROJECT SUMMARY Mutations arise as a result of exogenous and endogenous processes that leave characteristic imprints or signatures upon the genome. Systematic analysis of these mutational signatures led to the identification of >50 distinct types of single base substitutions (SBS) in human cancer genomes. Revealing the origins of individual signatures is critical for understanding cancer etiology, with potential implications for cancer prevention and therapy. Two of the most prevalent mutational signatures in cancer, termed SBS2 and SBS13, are present in >78% of cancer types and 56% of all cancer genomes, with a particular prominence in breast, bladder, and lung cancers. SBS2 and SBS13 are proposed to be caused by the endogenous APOBEC3 (A3) enzymes, which target ssDNA and RNA of viruses and retroelements as part of the innate immune defense. Correlations between A3 expression, driver gene mutations in A3-preferred contexts, and clinical outcomes suggest that A3 mutagenesis may play important roles in cancer etiology and evolution. Thus, there is strong rationale to understand the mechanisms of A3 activity. However, reliance on engineered model systems and correlative data have caused links between A3 enzymes, mutations in cancer, and cancer etiology to be poorly understood. We have identified human cancer cell lines with endogenous A3 mutagenesis and developed a workflow that enables us to quantify contributions of individual A3 members to mutations. Here, we propose to leverage this workflow to accomplish the following goals: 1) Identify A3 mutator enzymes in cancer types where A3 mutagenesis is prevalent and find biomarkers of their activity; 2) Investigate mechanisms modulating A3 mutagenesis; 3) Determine the functional relevance of A3 mutagenesis in therapy resistance and metastasis. Aim 1 will expand upon our characterization of human cancer cells with active A3 mutagenesis to identify A3 mutators in breast, bladder, and lung cancers. In parallel, we will directly assess the unknown specificity and sensitivity of assays to measure activities of individual A3 enzymes. These experiments may further confirm the speculative A3-etiology of a large number of cancer mutations and quantify contributions of individual A3 enzymes, thus nominating them as putative targets for therapeutic pursuit. Aim 2 builds on our preliminary data to investigate proposed modulators of A3 mutagenesis. These experiments have the potential to broaden the scope of therapeutic opportunities focused on cancer cell evolution. Aim 3 will assess the links between A3 enzymes, therapy resistance and metastasis in breast, bladder, and lung cancer cell lines. These experiments will test predictions from multi-dimensional associations that A3-mutagenesis is a disease-modifying process that can be therapeutically exploited at various stages of cancer evolution. Taken together, these studies will define the etiologies of highly prevalent mutational processes and identify strategies to elicit more durable clinical benefits to targeted therapies and curb metastasis.