Posttranslational Regulation of FOXA1 in Breast Cancer

FOXA1 在乳腺癌中的翻译后调控

• 批准号: 10504308
• 负责人: Hector Luis Franco
• 金额: $ 47.89万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2027-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10504308
• 关键词: ATAC-seq; Acetylation; Affect; Amino Acids; Antibodies; Automobile Driving; Binding; Binding Sites; Biological; Biophysics; Biotin; Breast Cancer cell line; Cancer Biology; Cancer Etiology; Cell Line; Cells; ChIP-seq; Chromatin; Clinical; Clustered Regularly Interspaced Short Palindromic Repeats; Coupled; Custom; DNA Binding; Data; Dependence; Developmental Process; Diagnosis; Endocrine; Endocrine system; Enhancers; Epigenetic Process; Epithelial Cells; Estrogen Receptor alpha; Estrogen Receptors; Estrogen receptor positive; Estrogens; Event; Gene Expression; Genes; Genetic; Genetic Screening; Genome; Genomics; Goals; Hormone Receptor; Human; Immune system; Immunoprecipitation; Inflammation; Inflammatory; Knock-in; Label; Ligands; Ligase; Link; Logic; Lysine; Malignant Neoplasms; Mammaplasty; Mammary Neoplasms; Mass Spectrum Analysis; Measures; Mediating; Molecular; Normal Cell; Nuclear Receptors; Nucleosomes; Outcome; Patients; Physiological Processes; Play; Post-Translational Protein Processing; Post-Translational Regulation; Primary Neoplasm; Proteins; Proteomics; Reader; Reagent; Receptor Signaling; Regulation; Resistance; Role; Signal Transduction; Site; Specimen; Stimulus; Structure; TNF gene; Tamoxifen; Techniques; Testing; Therapeutic; Therapeutic Intervention; Time; Tissues; Transferase; Up-Regulation; Woman; base; breast tumorigenesis; cancer cell; cytokine; experimental study; global run on sequencing; hormone therapy; inhibitor; malignant breast neoplasm; mortality; mouse model; mutant; novel; patient derived xenograft model; prevent; programs; protein structure; receptor binding; recruit; response; single-cell RNA sequencing; success; targeted treatment; therapeutic target; therapy design; transcription factor; transcriptome sequencing; tumor; tumorigenesis

Project Summary Breast cancer is the second leading cause of cancer mortality in women and nearly 75% of all breast tumors express estrogen receptor alpha (ER) at the time of diagnosis. Despite the therapeutic successes of endocrine therapies designed to target ER function, about 30-40% of tumors become resistant to endocrine therapy, either through de novo or acquired resistance, and still retain the expression of ER. Herein we propose to study the regulation of FOXA1, a pioneer transcription factor that enables ER binding to chromatin, whose theoretical inhibition would circumvent known mechanisms of endocrine therapy resistance. In breast cancer, FOXA1 is responsible for almost all of the ER binding events in the genome and its upregulation is associated with enhancer reprograming in endocrine resistance. However, there is a paucity of information about how FOXA1 itself is regulated and how cancer cells repurpose its pioneering activities to drive oncogenesis. To this end, our lab has been studying the crosstalk between the endocrine and immune systems in breast cancer. We have discovered that FOXA1, in response to the proinflammatory cytokines, is driven to non- canonical sites across the genome to promote chromatin accessibility for estrogen-liganded ER. These newly formed enhancers were found in compacted/latent regions of the genome and promoted the expression of a novel gene set that was predictive of poor clinical outcomes in patients. Concurrently, we discovered that FOXA1 is post-translationally modified (PTM) in response to proinflammatory cytokines at two evolutionarily conserved amino acids. The post-translational modification of FOXA1 in response to external stimuli has not been shown before and suggests an important mechanism that underlies FOXA1 regulation and function. Therefore, the overall goal of this project is to determine the molecular events that allow proinflammatory signaling to alter endocrine signaling through modulation of FOXA1 function and the biological consequences of this crosstalk. We hypothesize that estrogen- and TNFα-directed PTMs of FOXA1 dictate binding site selection, driving ERα to non-canonical enhancers across the genome, leading to expression programs that underlie the tumorigenesis of breast cancer. To systematically test this hypothesis, will use an integrated set of molecular, genomic, and proteomic approaches to: (Aim 1) define the role of FOXA1 PTMs on its pioneering function and chromatin occupancy, (Aim 2) identify the writers and readers of FOXA1 PTMs, and (Aim 3) understand inflammation- based modulation of FOXA1 independent of PTMs. We will perform these experiments in breast cancer cell lines, ER+ patient-derived xenografts (PDX), and in ER+ mature luminal cells isolated from patient tumors. The dependence on FOXA1 for hormone receptor signaling makes it an attractive therapeutic target. While there are currently no known inhibitors of FOXA1 and its protein structure makes it difficult to target therapeutically, our ability to understand basic molecular mechanisms is directly correlated with our ability to develop better therapeutic interventions. Defining how FOXA1 is regulated becomes key to this endeavor.

项目概要 乳腺癌是女性癌症死亡的第二大原因，占所有乳腺癌死亡人数的近 75% 肿瘤在诊断时表达雌激素受体α（ER）。尽管治疗取得了成功 针对 ER 功能而设计的内分泌疗法，约 30-40% 的肿瘤对内分泌产生耐药性 通过从头或获得性耐药进行治疗，并且仍然保留 ER 的表达。在此我们建议 研究 FOXA1 的调控，FOXA1 是一种先驱转录因子，可使 ER 与染色质结合，其 理论上的抑制将规避已知的内分泌治疗耐药机制。在乳腺癌中， FOXA1 负责基因组中几乎所有的 ER 结合事件，并且其上调与之相关 与内分泌抵抗的增强子重编程。然而，关于如何进行的信息却很少 FOXA1 本身受到调节，以及癌细胞如何重新利用其开创性活动来驱动肿瘤发生。 为此，我们的实验室一直在研究内分泌系统和免疫系统之间的串扰。 乳腺癌。我们发现 FOXA1 响应促炎细胞因子，被驱动为非 跨基因组的规范位点，以促进雌激素配体 ER 染色质的可及性。这些新 在基因组的压缩/隐藏区域中发现了形成的增强子，并促进了 预测患者不良临床结果的新基因组。同时，我们发现FOXA1 在两个进化上保守的位置对促炎细胞因子进行翻译后修饰（PTM） 氨基酸。 FOXA1 响应外部刺激的翻译后修饰尚未被证实 之前并提出了 FOXA1 调节和功能的重要机制。因此， 该项目的总体目标是确定允许促炎症信号改变的分子事件 通过调节 FOXA1 功能的内分泌信号传导以及这种串扰的生物学后果。 我们假设 FOXA1 的雌激素和 TNFα 导向的 PTM 决定结合位点选择，驱动 ERα 跨基因组的非规范增强子，导致肿瘤发生的表达程序 乳腺癌。为了系统地检验这一假设，我们将使用一套完整的分子、基因组和 蛋白质组学方法：（目标 1）定义 FOXA1 PTM 对其先驱功能和染色质的作用 占用率，（目标 2）识别 FOXA1 PTM 的作者和读者，以及（目标 3）了解炎症- 独立于 PTM 的 FOXA1 调制。我们将在乳腺癌细胞中进行这些实验 细胞系、ER+ 患者来源的异种移植物 (PDX) 以及从患者肿瘤分离的 ER+ 成熟管腔细胞中。这 激素受体信号转导对 FOXA1 的依赖性使其成为有吸引力的治疗靶点。虽然有 目前尚无已知的 FOXA1 抑制剂，其蛋白质结构使其难以靶向治疗，我们的 了解基本分子机制的能力与我们更好地发展的能力直接相关 治疗干预。定义 FOXA1 的监管方式成为这一努力的关键。