Genome-wide analysis of the formation and mutagenesis of atypical UV photoproducts in skin cancer

皮肤癌中非典型紫外线光产物的形成和诱变的全基因组分析

• 批准号: 10179949
• 负责人: STEVEN A ROBERTS
• 金额: $ 41.69万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-01 至 2026-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10179949
• 关键词: Acute; Adenine; BRAF gene; Bioinformatics; Bulla; Bypass; Cells; Characteristics; Cleaved cell; Clinical; Cutaneous Melanoma; Cytidine; Cytosine; DNA Damage; DNA biosynthesis; DNA-Directed DNA Polymerase; Data; Deamination; Deoxyribonuclease I; Dinucleoside Phosphates; Disease Progression; Epidemiology; Etiology; Exposure to; Genetic Transcription; Genome; Genomics; High-Throughput Nucleotide Sequencing; Human; In Vitro; Incidence; Induced Mutation; Lesion; Light; Link; Location; Maps; Methods; Molecular; Mutagenesis; Mutation; Nucleotide Excision Repair; Nucleotides; Oncogenic; Physiological; Play; Polymerase; Proto-Oncogenes; Pyrimidine Dimers; Rad30 protein; Rare Lesion; Recurrence; Reporter; Resolution; Role; Skin; Skin Cancer; Somatic Mutation; Sunburn; Sunlight; Thymine; UV Mutagenesis; UV Radiation Exposure; UV induced; UVA induced; Ultraviolet B Radiation; Ultraviolet Rays; Yeasts; base; density; driver mutation; experimental study; genome sequencing; genome-wide; genome-wide analysis; insight; melanoma; melanomagenesis; novel; regional difference; repaired; response; skin organogenesis; tumor; tumor progression; ultraviolet; ultraviolet damage; ultraviolet lesions; whole genome

Abstract: Exposure to solar ultraviolet (UV) light creates DNA damage that induces high levels of somatic mutations in human skin cancers like melanoma. UV light most commonly causes cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4PPs) at dipyrimidine sequences (i.e., TT, TC, CT, and CC). Deamination of cytidines in these lesions or mutagenic bypass leads to their frequent conversion to mutations. As a result, UV- exposed cells and skin cancers are dominated by C to T and CC to TT substitutions in dipyrimidine sequences that collectively constitute a UV mutation signature. Surprisingly, many driver mutations that contribute to melanoma progression have sequence context and substitution characteristics that do not conform to the canonical UV mutation signature. For example, the most common melanoma driver mutation, BRAF V600E, involves a T to A substitution in a GTG sequence context. This difference in mutation characteristics between most UV-induced mutations and melanoma driver mutations has led to the hypothesis that UV light induces melanomagenesis by mechanisms other than the induction of mutations. However, we have recently provided experimental evidence of mutations caused by rare, non-canonical UV lesions in whole genome sequenced yeast and bioinformatics evidence of similar lesions in human clinical skin cancers. These lesions are likely bulky photoproducts formed at TA, CA, and AC dinucleotides. Strikingly, the mutations associated with these atypical UV photoproducts have identical characteristics to many recurrent driver mutations in melanoma, suggesting that these rare lesions may play a significant role in causing skin cancer. The objective of this proposal is to better define the characteristics of atypical UV photoproducts and their contribution to cancer progression. In Aim I, we will utilize CPD and 6-4PP photolyases expressed in yeast to assign UV-induced mutation classes to their corresponding lesion types as well as assess the ability of physiological UVB light to induce mutation classes associated with atypical UV photoproducts in yeast and human cells. In Aim II, we will analyze the genome-wide distribution of atypical TA photoproducts using a novel high throughput sequencing method, called UVDE-seq. We will also characterize the formation of putative CA and AC photoproducts and their contribution to oncogenic BRAF mutations. Finally, Aim III will identify DNA polymerases involved in the error-free and error-prone bypass of TA and AC photoproducts. Successful completion of these aims will provide new insights into the molecular causes of skin cancer, and thereby define a new paradigm of UV mutagenesis that could potentially explain the epidemiological association of acute UV exposure with increased melanoma incidence.

抽象的： 暴露于太阳能紫外线（UV）光会造成DNA损伤，从而引起高水平的体细胞突变 人类皮肤癌等黑色素瘤。紫外线最常导致环丁烷嘧啶二聚体（CPD） 在二吡啶定序列（即TT，TC，CT和CC）处的6-4个光药物（6-4pp）。解开 这些病变或诱变旁路中的胞苷会导致它们频繁地转化为突变。结果，UV- 暴露的细胞和皮肤癌由C至T和CC支配到Dipyrimidine序列中的TT取代 这共同构成了紫外线突变签名。令人惊讶的是，许多有助于 黑色素瘤的进展具有不符合的序列上下文和替代特征 规范紫外线突变签名。例如，最常见的黑色素瘤驱动器突变BRAF V600E， 在GTG序列上下文中涉及替换。这种突变特征之间的差异 大多数紫外线引起的突变和黑色素瘤驱动突变导致了紫外线诱导的假设 通过除诱导突变以外的机制，黑色素作发生。但是，我们最近提供了 在整个基因组中，由罕见的非经典紫外病变引起的突变的实验证据。 人类临床皮肤癌中类似病变的酵母和生物信息学证据。这些病变可能是 在TA，CA和AC二核苷酸中形成的笨重光药物。令人惊讶的是，与这些相关的突变 非典型紫外线光药物与黑色素瘤中许多复发驱动突变具有相同的特征， 表明这些罕见的病变可能在引起皮肤癌中起重要作用。这个目的 提案是更好地定义非典型紫外线光药物的特征及其对癌症的贡献 进展。在AIM I中，我们将利用CPD和6-4pp的光溶液在酵母中表达 对相应病变类型的突变类别以及评估生理UVB光的能力 诱导与酵母和人类细胞中非典型紫外光产物相关的突变类别。在AIM II中，我们将 使用新型的高吞吐量测序分析非典型TA光药物的全基因组分布 方法，称为uvde-seq。我们还将表征推定的CA和AC光产物的形成以及 它们对致癌BRAF突变的贡献。最后，AIM III将确定与 TA和AC光子产物的无误和旁路旁路。这些目标的成功完成将 对皮肤癌的分子原因提供新的见解，从而定义了紫外线的新范式 诱变可能可以解释急性紫外线暴露与 黑色素瘤发病率增加。