IncRNA BORG Mediates Alternative Splicing to Enhance Cellular Plasticity in TNBC

IncRNA BORG 介导选择性剪接以增强 TNBC 中的细胞可塑性

基本信息

批准号：
10153025
负责人：
Kimberly Parker
金额：
$ 3.72万
依托单位：
CASE WESTERN RESERVE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-06-01 至 2024-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10153025
关键词：
Address Alternative Splicing Apoptotic Automobile Driving Behavior Binding Biopsy Breast Cancer Patient Breast cancer metastasis Cancer Etiology Cell Cycle Progression Cell Survival Cell physiology Cells Cessation of life Chemoresistance Complex Data Disease Distal Down-Regulation ERBB2 gene Enhancers Epigenetic Process Estrogen Receptors Event FDA approved Frequencies GADD45A gene Gene Expression Gene Silencing Genes Growth Growth Factor Receptors Health Implant In Vitro Incidence Individual Knowledge Laboratories Ligase Location Mammospheres Measures Mediating Modification Molecular Neoplasm Metastasis Pathway interactions Patient-Focused Outcomes Phenotype Play Primary Neoplasm Process Progesterone Receptors Prognosis Proliferating RNA Interference RNA Splicing Recurrence Relapse Ribonucleoproteins Role SRSF2 gene Signal Transduction Site Spliced Genes Stem Cell Development Thromboplastin Transcript United States Untranslated RNA Variant Woman base cancer stem cell cancer subtypes cell motility differential expression epigenome epithelial to mesenchymal transition in vitro Assay in vivo innovation knock-down malignant breast neoplasm neoplastic neoplastic cell new therapeutic target novel programs response self-renewal stem cell biomarkers stem-like cell stemness targeted treatment transcriptomics triple-negative invasive breast carcinoma tumor growth tumorigenic

项目摘要

Project Summary/Abstract Breast cancer (BC) is the second leading cause of cancer-related deaths among women in the United States. A subset of BC called triple-negative breast cancer (TNBC) has the worst prognosis among BC subtypes, due to both the frequency and location of the resulting metastases. In TNBC, the underlying mechanisms that mediate metastatic outgrowth after disseminated tumor cells implant into distal sites is unknown. However, our laboratory recently identified the long noncoding RNA, BORG (BMP/OP-Response Gene), as a driver of TNBC metastasis. Indeed, BORG expression enhances neoplastic proliferation and chemoresistance, which are important cellular functions associated with metastatic phenotypes. Mechanistically, our group showed that BORG complexes with the E3 SUMO ligase TRIM28 in order to enhance neoplastic proliferation by repressing the expression of the growth arrest genes, p21 and gadd45a. Herein, I will show that the proliferative and cell survival pathways activated by BORG reflect breast cancer stem cell (BCSC) phenotypes. Importantly, I demonstrate that BORG enhances BCSC mammosphere formation and tumor growth both in vitro and in vivo, and that this phenotype relies in part on the formation of BORG:TRIM28 complexes. However, the mechanisms through which BORG and TRIM28 enhance BCSC plasticity are not yet understood. To this end, I find that BORG expression causes significant transcriptomic reprogramming, suggesting that BORG enhances cellular plasticity by mediating transcriptomic changes (e.g., alternative splicing) which broadly influences BCSC-like phenotypes. Accordingly, I showed that BORG expression plays a role in alternative splicing by upregulating 61 alternative splicing events (ASEs) and downregulating 83 ASEs, including a number of ASEs whose genes are involved in key metastatic pathways. Moreover, I determined that BORG downregulates the expression of 38 splicing factors, and up- regulates the expression of 6 splicing factors. Interestingly, the downregulation of 16 of these splicing factors relies upon BORG:TRIM28 complexes. Based on these preliminary data, I hypothesize that BORG:TRIM28 complexes drive BCSC plasticity and metastasis by regulating the epigenome and ASEs involved in metastatic phenotypes. To elucidate how BORG influences alternative splicing, I will (i) determine the mechanism(s) by which BORG:TRIM28 complexes regulate the expression and activity of splicing factors to drive variations in alternative splicing; and (ii) elucidate the consequences of BORG-induced ASEs on tumor cell plasticity and BCSC phenotypes. To our knowledge, my innovative analyses are the first to investigate the interaction between BORG and alternative splicing in promoting the metastatic features of TNBCs. By elucidating molecular mechanisms whereby BORG drives alternative splicing, we can better understand how lncRNAs elicit such drastic phenotypic changes to drive metastatic behaviors in TNBCs. Importantly, BORG-induced ASEs may provide new therapeu- tic targets to treat and alleviate metastatic TNBCs.

项目概要/摘要乳腺癌（BC）是美国女性癌症相关死亡的第二大原因。一个 BC 亚型称为三阴性乳腺癌 (TNBC)，其预后在 BC 亚型中最差，原因是由此产生的转移的频率和位置。在 TNBC 中，调解的基本机制播散性肿瘤细胞植入远端部位后的转移生长尚不清楚。然而，我们的实验室最近发现长非编码 RNA BORG（BMP/OP 响应基因）是 TNBC 转移的驱动因素。事实上，BORG 表达增强肿瘤增殖和化疗耐药性，这是重要的细胞与转移表型相关的功能。从机制上讲，我们的小组表明 BORG 复合体与 E3 SUMO 连接酶 TRIM28 一起通过抑制表达来增强肿瘤增殖生长停滞基因 p21 和 gadd45a。在这里，我将展示增殖和细胞存活途径 BORG 激活反映了乳腺癌干细胞 (BCSC) 表型。重要的是，我证明了 BORG 在体外和体内增强 BCSC 乳腺球的形成和肿瘤生长，并且这种表型部分依赖于 BORG:TRIM28 复合物的形成。然而，BORG 的机制 TRIM28增强BCSC可塑性尚不清楚。为此，我发现BORG表达式导致显着的转录组重编程，表明 BORG 通过介导转录组变化（例如选择性剪接）来增强细胞可塑性，从而广泛影响 BCSC 样表型。据此，我表明 BORG 表达通过上调 61 个选择性剪接事件在选择性剪接中发挥作用 (ASE) 并下调 83 个 ASE，其中包括一些基因参与关键转移的 ASE 途径。此外，我确定 BORG 下调 38 个剪接因子的表达，并上调调节6个剪接因子的表达。有趣的是，其中 16 个剪接因子的下调依赖于 BORG:TRIM28 复合物。根据这些初步数据，我假设 BORG:TRIM28 复合物通过调节参与转移的表观基因组和 ASE 来驱动 BCSC 可塑性和转移表型。为了阐明 BORG 如何影响选择性剪接，我将 (i) 通过以下方式确定机制：哪些 BORG:TRIM28 复合物调节剪接因子的表达和活性以驱动选择性剪接的变化； (ii) 阐明 BORG 诱导的 ASE 对肿瘤细胞可塑性和 BCSC 的影响表型。据我们所知，我的创新分析是第一个研究 BORG 之间相互作用的分析选择性剪接促进 TNBC 的转移特征。通过阐明分子机制通过 BORG 驱动选择性剪接，我们可以更好地理解 lncRNA 如何引发如此剧烈的表型驱动 TNBC 转移行为的变化。重要的是，BORG 诱导的 ASE 可能提供新的治疗方法 tic 目标是治疗和缓解转移性 TNBC。